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Scientific Investigations Report 2006-5002

In cooperation with the West Virginia Department of Environmental Protection, Division Of Water and Waste Management

Low-Flow Analysis and Selected Flow Statistics Representative of 1930–2002 for Streamflow-Gaging Stations In or Near West Virginia

By Jeffrey B. Wiley

The PDF for the report is 2,179 kb


Table of Contents

Abstract

Introduction

Patterns in Minimum Flows

Variability of Flow Statistics

Selected Flow Statistics Representative of 1930–2002

Summary

Acknowledgments

References Cited

Figures

Figure 1. U.S. Geological Survey streamflow-gaging stations in or ne...

Figure 2. Departure of the minimum flows from the record-period aver...

Figure 3. Departure of the unit minimum flows from the record-period...

Figure 4. Average standardized departures of the minimum flows from ...

Figure 5. Average standardized departures of the minimum flows from ...

Figure 6. Average standardized departures of the minimum flows from ...

Figure 7. Departure of the minimum flows from the record-period aver...

Figure 8. U.S. Geological Survey streamflow-gaging stations used to ...

Figure 9. Average standardized departures of the minimum flows from ...

Figure 10. Average standardized departures of the minimum flows from...

Figure 11. Average standardized departures of the minimum flows from...

Figure 12. Record periods for the Lower Appalachian Plateaus region ...

Figure 13. Record periods for the Upper Appalachian Plateaus region ...

Figure 14. Record periods for the Eastern Panhandle region for which...

Figure 15. Unit average minimum flows for the entire record period a...

Figure 16. Unit average minimum flows for the subset record period a...

Tables

Table 1. U.S. Geological Survey streamflow-gaging stations in or nea...

Table 2. Average differences between selected annual statistics comp...

Table 3. Differences between selected annual statistics computed for...

Table 4. Average differences between selected seasonal statistics co...

Table 5. Differences between selected seasonal statistics computed f...

Table 6.— Average annual and seasonal differences between the 1-day 1...

Table 7. Annual and seasonal differences between the 1-day 10-year h...

Table 8. Record periods for the Lower Appalachian Plateaus region fo...

Table 9. Record periods for the Upper Appalachian Plateaus region fo...

Table 10. Record periods for the Eastern Panhandle region for which ...

Table 11. Selected annual and seasonal statistics for 77 stations in...

Table 12. Selected annual and seasonal statistics for 40 stations in...

Table 13. Comparison between the average minimum flows computed for ...


Conversion Factors and Datums

Multiply By To obtain
Length
inch (in.) 2.54 centimeter (cm)
inch (in.) 25.4 millimeter (mm)
foot (ft) 0.3048 meter (m)
mile (mi) 1.609 kilometer (km)
Area
square foot (ft2) 0.0929 square meter (m2)
square mile (mi2) 2.590 square kilometer (km2)
Volume
cubic foot (ft3) 0.02832 cubic meter (m3)
Flow rate
cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Abstract

Five time periods between 1930 and 2002 are identified as having distinct patterns of annual minimum daily mean flows (minimum flows). Average minimum flows increased around 1970 at many streamflow-gaging stations in West Virginia. Before 1930, however, there might have been a period of minimum flows greater than any period identified between 1930 and 2002. The effects of climate variability are probably the principal causes of the differences among the five time periods.

Comparisons of selected streamflow statistics are made between values computed for the five identified time periods and values computed for the 1930–2002 interval for 15 streamflow-gaging stations. The average difference between statistics computed for the five time periods and the 1930–2002 interval decreases with increasing magnitude of the low-flow statistic. The greatest individual-station absolute difference was 582.5 percent greater for the 7-day 10-year low flow computed for 1970–1979 compared to the value computed for 1930–2002. The hydrologically based low flows indicate approximately equal or smaller absolute differences than biologically based low flows. The average 1-day 3-year biologically based low flow (1B3) and 4-day 3-year biologically based low flow (4B3) are less than the average 1-day 10-year hydrologically based low flow (1Q10) and 7-day 10-year hydrologic-based low flow (7Q10) respectively, and range between 28.5 percent less and 13.6 percent greater. Seasonally, the average difference between low-flow statistics computed for the five time periods and 1930–2002 is not consistent between magnitudes of low-flow statistics, and the greatest difference is for the summer (July 1–September 30) and fall (October 1–December 31) for the same time period as the greatest difference determined in the annual analysis. The greatest average difference between 1B3 and 4B3 compared to 1Q10 and 7Q10, respectively, is in the spring (April 1–June 30), ranging between 11.6 and 102.3 percent greater.

Statistics computed for the individual station's record period may not represent the statistics computed for the period 1930 to 2002 because (1) station records are available predominantly after about 1970 when minimum flows were greater than the average between 1930 and 2002 and (2) some short-term station records are mostly during dry periods, whereas others are mostly during wet periods. A criterion-based sampling of the individual station's record periods at stations was taken to reduce the effects of statistics computed for the entire record periods not representing the statistics computed for 1930–2002. The criterion used to sample the entire record periods is based on a comparison between the regional minimum flows and the minimum flows at the stations. Criterion-based sampling of the available record periods was superior to record-extension techniques for this study because more stations were selected and areal distribution of stations was more widespread. Principal component and correlation analyses of the minimum flows at 20 stations in or near West Virginia identify three regions of the State encompassing stations with similar patterns of minimum flows: the Lower Appalachian Plateaus, the Upper Appalachian Plateaus, and the Eastern Panhandle. All record periods of 10 years or greater between 1930 and 2002 where the average of the regional minimum flows are nearly equal to the average for 1930–2002 are determined as representative of 1930–2002. Selected statistics are presented for the longest representative record period that matches the record period for 77 stations in West Virginia and 40 stations near West Virginia. These statistics can be used to develop equations for estimating flow in ungaged stream locations.

Introduction

Information on the low-flow statistics of streams is essential for development and management of West Virginia's surface-water resources. Such information is useful for assessing the availability of water for municipal or industrial supplies, irrigation, recreation, aquatic life and wildlife conservation, and disposal of liquid wastes. Low-flow statistics also are useful as a basis for forecasting seasonal low flows, as indicators of the amount of ground-water inflow to streams, and as legal indexes for maintaining water-quality standards.

Low flows can be affected by mining (Hobba, 1981; Puente and Atkins, 1989; Borchers and others, 1991; Wiley and others, 2001); urbanization; land-use practices such as logging and farming; and construction of small detention reservoirs for flood control, recreation, and low-flow augmentation. Low flows that may be associated with climate change also have been observed (Karl and Knight, 1998; Lins and Slack, 1999; McCabe and Wolock, 2002).

The reliability of low-flow frequency curves is related to the record period, and confidence is increased if the record period includes a substantial drought; a record period representing long-term flow characteristics is desired (Riggs, 1972, p. 6). Arbitrarily using entire record periods at streamflow-gaging stations will result in statistics that, for some stations, represent wet or dry periods because all or most of the entire record period is significantly different from average conditions over a longer term. Low-flow statistics representative of average conditions expected over a defined time period that includes a substantial drought are better than arbitrary use of entire record periods from stations that may not represent long-term average conditions.

Previous Studies of National Trends in Streamflow Statistics

An increase in low flows in the eastern United States around 1970 was identified by McCabe and Wolock (2002). The annual maximum, median, and minimum daily mean flows for 400 streamflow-gaging stations across the entire United States were analyzed for 1941–99. A standardized departure at each station was computed by subtracting the average annual maximum, median, and minimum daily mean flows for 1941–99 from the respective daily flows at each station and then dividing by the respective standard deviation. The standardized departures were averaged for all 400 stations for each year. An abrupt change in the average standardized departures from a negative value to a positive value was apparent at about 1970, indicating an increase in flows. The increase was most evident in the minimum and median flows. The increase in flows around 1970 was coincident with increases in precipitation, particularly in the fall (September 1–November 30), in the eastern United States (Karl and Knight, 1998).

Lins and Slack (1999) studied 395 streamflow-gaging stations across the United States for changes in flow for 1944–93. By the use of the Mann-Kendall test, flows were evaluated at several flow percentiles between and including the annual minimum and annual maximum daily mean flows for six time periods between 1944 and 1993. The study indicated an increase in flow for the annual minimum to about the 50-percent flow percentile but no significant increase or decrease in annual maximum flow. Causes for the trends observed were associated with precipitation patterns, variations in ocean characteristics, and increasing atmospheric carbon dioxide in climate model simulations.

Purpose and Scope

This report, prepared in cooperation with the West Virginia Department of Environmental Protection, Division of Water and Waste Management, evaluates patterns in the annual minimum daily mean flows, referred to as "minimum flows" in this report, and low-flow statistics at U.S. Geological Survey streamflow-gaging stations in or near West Virginia (fig. 1). Five periods consisting of similar patterns in minimum flows are identified, and some flow statistics are computed for those periods. The flow statistics for the periods are compared to the statistics for the long-term period (1930–2002) to quantify the magnitude of statistical variability of low flows. A procedure is developed to select record periods at stations that are representative of streamflows for a long time period (relative to the length of available records) that can be used to develop estimating equations for flow at ungaged stream locations. Selected flow statistics are computed for stations in or near West Virginia. Statistics for stations in West Virginia supersede those published by Friel and others (1989). Statistics for stations in surrounding states can be used to assist in estimating flows for West Virginia but do not supersede the values determined for use in that state.


Map showing U.S. Geological Survey streamflow-gaging stations in or near West Virginia considered in this study.

Figure 1. U.S. Geological Survey streamflow-gaging stations in or near West Virginia considered in this study.


Selected Flow Statistics and Methods of Statistical Analysis

The following statistics were computed for this study: the annual-minimum daily-mean flow (minimum flow); the 1-day 2-year (1Q2), 1-day 5-year (1Q5), 1-day 10-year (1Q10), 3-day 2-year (3Q2), 3-day 5-year (3Q5), 3-day 10-year (3Q10), 7-day 2-year (7Q2), 7-day 5-year (7Q5), 7-day 10-year (7Q10), 14-day 2-year (14Q2), 14-day 5-year (14Q5), 14-day 10-year (14Q10), 30-day 2-year (30Q2), 30-day 5-year (30Q5), and 30-day 10-year (30Q10) hydrologically based low-flow frequencies; the 1-day 3-year (1B3) and 4-day 3-year (4B3) biologically based low-flow frequencies; the U.S. Environmental Protection Agency (EPA) harmonic-mean flows; the 5-, 10-, 15-, 20-, 25-, 30-, 35-, 40-, 45-, 50-, 55-, 60-, 65-, 70-, 75-, 80-, 85-, 90-, 95-, and 99-percent flow durations; and the variability index. The following statistical methods were used: the Mann-Kendall test for trend (Mann, 1945; Kendall 1975; Hirsch and others, 1982; Helsel and Hirsch, 2002), principal component analysis, and correlation (Helsel and Hirsch, 2002).

Hydrologically based low-flow frequencies were determined by use of methods described by Riggs (1972). The general approach is as follows. An annual series of the minimum n-day (number of consecutive days) daily mean low flows are fitted to a log-Pearson Type III probability curve. A plot of the probability curve and data are reviewed for fitness. Other probability distributions are considered, or a smooth curve is constructed through the data if the data do not fit the log-Pearson Type III probability curve. The frequency of the n day is computed from the fitted probability curve or read from the smooth curve constructed through the data. (All data fit the log-Pearson Type III probability curve in this study.) For example, The 7Q2 would be the streamflow at the 2-year recurrence interval taken from a frequency curve of annual values of the lowest mean streamflow for 7 consecutive days; the 7-day flow will be less than the 7Q2 at intervals averaging 2 years in length; or the probability is 1/2 that the 7-day low flow in any one year will be less than 7Q2.

Biologically based low-flow frequencies were determined by use of methods described by the U.S. Environmental Protection Agency (1986). For these statistics, a daily series of average n-day daily mean flows is computed for a streamflow record. Unlike the hydrologically based statistics, the biologically based statistics are computed by identification of "excursions" in the record. An excursion is a low-flow period that is determined to be hydrologically separate from other low-flow periods, typically by a measure of a minimum of 120 days between excursions. (The excursion concept relates to the biological concept of aquatic-life recovery after a period of stress.) The n-day series is evaluated for the desired frequency of occurrence of the excursions on the basis of number of years of record. For example, the 4B3 would be the streamflow at the 3-year recurrence interval of excursions of the lowest mean streamflow for 4 consecutive days; the 4-day flow will be less than the 4B3 at intervals averaging 3 years in length; or the probability is 1/3 that the 4-day low flow in any one year will be less than 4B3.

The EPA harmonic-mean flows were determined by use of methods described by Rossman (1990). The average of the reciprocals of the daily mean flows is computed for a station record. The harmonic-mean flow is the reciprocal of that average. The EPA harmonic-mean flow is the weighted average of the harmonic mean of the nonzero flows and the arithmetic mean of the zero flows; the harmonic mean of the nonzero flows is multiplied by the number of nonzero days and divided by the total number of days.

Flow durations were determined by use of methods described by Searcy (1959). A yearly record of daily mean flows is divided into 20–30 classes of average flows. Every complete year of record at a station is divided into the same classes. The number of days in each class is computed for the entire record period, and the percentage of the time a flow is in each class is determined. A particular flow duration is extrapolated from the class percentiles, and a log-probability plot of the class percentiles is a flow-duration curve. For example, the 5-percent-duration streamflow is equaled or exceeded 5 percent of the time.

The variability index was determined by use of methods described by Lane and Lei (1950). The variability index is a measure of the slope of the flow-duration curve. The variability index is the standard deviation of the logarithms of flow durations at 10-percent intervals between 5 and 95 percent. A variant of the method used to compute the variability index was necessary when the 95-percent flow duration was 0.00 ft3; the 95- and 5-percent flow durations were excluded from the computation, and the standard deviation was computed for the logarithms of flow durations at 10-percent intervals between 15 and 85 percent. The variability index increases as the slope of the flow-duration curve increases, indicating that as the variability Index increases, the permeability and storage capacity of the base-flow aquifer for a stream decrease. Flows in streams with higher variability indexes will reduce more rapidly during base-flow periods than flows in streams with lower variability indexes.

The statistics and statistical analyses were computed by use of the computer programs (1) SWSTAT, version 4.1 (Lumb and others, 1990; written commun., from USGS colleagues A.M. Lumb, W.O. Thomas, Jr., and K.M. Flynn, titled "Users manual for SWSTAT, a Computer Program for Interactive Computation of Surface-Water Statistics," June 15, 1995), (2) DFLOW, version 3.0 (Rossman, 1990), and (3) S-PLUS 2000 (MathSoft, Inc., 1999). SWSTAT was used to compute hydrologically based statistics and statistics for the Mann-Kendall test for trend; DFLOW was used to compute biologically based low-flow frequencies and the EPA harmonic-mean flow; and S-PLUS 2000 was used to compute statistics for the principal component and correlation analyses.

DFLOW has the capability to compute both hydrologically and biologically based frequencies. Hydrological frequencies determined with DFLOW were not equal to those determined using SWSTAT because SWSTAT applies an adjustment for zero values along with other computational differences. Hydrological frequencies determined with DFLOW were greater than those determined with SWSTAT if zero values were in the analysis. Hydrological frequencies determined with DFLOW were often greater than twice those determined with SWSTAT. Only the biological frequencies determined with DFLOW are presented in this report, and the hydrological frequencies presented herein were computed with SWSTAT.

Patterns in Minimum Flows

Patterns of minimum flows at streamflow-gaging stations in West Virginia were investigated by use of methods similar to those used by McCabe and Wolock (2002). The minimum flows for the climatic year were determined for 110 stations in West Virginia having a minimum of 10 years of unregulated low-flow record (table 1). Table 1 contains all stations in West Virginia with at least 10 years of record, although some stations do not have record periods meeting the criteria for analyses or publication of statistics (there are no dots in table 1 for some stations). The climatic year, as used in this study, is April 1 through March 31of the indicated ending year; for example, the 1970 climatic year is April 1, 1969, through March 31, 1970. Use of climatic years maintains a continuous minimum low-flow period within each year because low flows in March and April are higher than average.

Table 1. U.S. Geological Survey streamflow-gaging stations in or near West Virginia considered in this study.

[MD, Maryland; WV, West Virginia; VA, Virginia; PA, Pennsylvania; OH, Ohio; KY, Kentucky; *, indicates that station is included in the indicated criterion]

Station number Station name State Analysis Selected stream-flow statistics published in this report
Increase in minimum flows around 1970 Minimum flows from 1930 to 2002 Minimum flows from 1930 to 1969 Minimum flows from 1970 to 2002 Regional minimum flows from 1930 to 2002
01595000 North Branch Potomac River at Steyer MD           *
01595300 Abram Creek at Oakmont WV *         *
01596000 North Branch Potomac River at Bloomington MD           *
01596500 Savage River near Barton MD           *
01597000 Crabtree Creek near Swanton MD           *
01598000 Savage River at Bloomington MD           *
01599500 New Creek near Keyser WV           *
01600000 North Branch Potomac River at Pinto MD           *
01603000 North Branch Potomac River near Cumberland MD           *
01604500 Patterson Creek near Headsville WV *     *   *
01605500 South Branch Potomac River at Franklin WV *         *
01606000 North Fork South Branch Potomac River at Cabins WV           *
01606500 South Branch Potomac River near Petersburg WV * * * * * *
01607500 South Fork South Branch Potomac River at Brandywine WV *     *   *
01608000 South Fork South Branch Potomac River near Moorefield WV *     *   *
01608500 South Branch Potomac River near Springfield WV * * * * * *
01609800 Little Cacapon River near Levels WV            
01610500 Cacapon River at Yellow Spring WV           *
01611500 Cacapon River near Great Cacapon WV * * * * * *
01612500 Little Tonoloway Creek near Hancock MD           *
01613900 Hogue Creek near Hayfield VA           *
01614000 Back Creek near Jones Springs WV *         *
01615000 Opequon Creek near Berryville VA           *
01616500 Opequon Creek near Martinsburg WV *     *   *
01617000 Tuscarora Creek above Martinsburg WV *          
01620500 North River near Stokesville VA           *
01632000 North Fork Shenandoah River at Cootes Store VA         * *
01632900 Smith Creek near New Market VA           *
01634500 Cedar Creek near Winchester VA           *
01636500 Shenandoah River at Millville WV * * * * * *
01637000 Little Catoctin Creek at Harmony MD           *
01637500 Catoctin Creek near Middletown MD           *
01638480 Catoctin Creek at Taylorstown VA           *
01643700 Goose Creek near Middleburg VA           *
01644000 Goose Creek near Leesburg VA         * *
02013000 Dunlap Creek near Covington VA         *  
03050000 Tygart Valley River near Dailey WV *   *     *
03050500 Tygart Valley River near Elkins WV *     *   *
03051000 Tygart Valley River at Belington WV * * * * * *
03051500 Middle Fork River at Midvale WV            
03052000 Middle Fork River at Audra WV *         *
03052500 Sand Run near Buckhannon WV *     *   *
03053500 Buckhannon River at Hall WV * * * * * *
03054500 Tygart Valley River at Philippi WV *     *   *
03056250 Three Fork Creek near Grafton WV           *
03056500 Tygart Valley River at Fetterman WV            
03057500 Skin Creek near Brownsville WV           *
03058000 West Fork River below Stonewall Jackson Dam near Weston WV *         *
03058500 West Fork River at Butcherville WV *   *     *
03059000 West Fork River at Clarksburg WV *   *     *
03059500 Elk Creek at Quiet Dell WV            
03060500 Salem Creek at Salem WV            
03061000 West Fork River at Enterprise WV *         *
03061500 Buffalo Creek at Barrackville WV * *   * * *
03062400 Cobun Creek at Morgantown WV            
03062500 Deckers Creek at Morgantown WV            
03065000 Dry Fork at Hendricks WV *         *
03066000 Blackwater River at Davis WV * * * * * *
03069000 Shavers Fork at Parsons WV *         *
03069500 Cheat River near Parsons WV * * * * * *
03070000 Cheat River at Rowlesburg WV *   *     *
03070500 Big Sandy Creek at Rockville WV * * * * * *
03071000 Cheat River near Pisgah WV           *
03071500 Cheat River near Morgantown WV            
03072000 Dunkard Creek at Shannopin PA           *
03072590 Georges Creek at Smithfield PA           *
03075500 Youghiogheny River near Oakland MD           *
03076600 Bear Creek at Friendsville MD           *
03085500 Chartiers Creek at Carnegie PA           *
03108000 Raccoon Creek at Moffatts Mill PA           *
03109500 Little Beaver Creek near East Liverpool OH         * *
03110000 Yellow Creek near Hammondsville OH           *
03111500 Short Creak near Dillonvale OH           *
03112000 Wheeling Creek at Elm Grove WV

*

    *   *
03114000 Captina Creek at Armstrongs Mills OH           *
03114500 Middle Island Creek at Little WV

*

 

*

    *
03115400 Little Muskingum River at Bloomfield OH           *
03151400 Little Kanawha River near Wildcat WV            
03151500 Little Kanawha River near Burnsville WV            
03152000 Little Kanawha River at Glenville WV

*

 

*

    *
03152500 Leading Creek near Glenville WV            
03153000 Steer Creek near Grantsville WV

*

        *
03153500 Little Kanawha River at Grantsville WV

*

 

*

    *
03154000 West Fork Little Kanawha River at Rocksdale WV

*

        *
03154500 Reedy Creek near Reedy WV

*

        *
03155000 Little Kanawha River at Palestine WV

*

        *
03155200 South Fork Hughes River at Macfarlan WV            
03155500 Hughes River at Cisco WV

*

        *
03173000 Walker Creek at Bane VA           *
03175500 Wolf Creek near Narrows VA           *
03178500 Camp Creek near Camp Creek WV            
03179000 Bluestone River near Pipestem WV a*     *   *
03179500 Bluestone River at Lilly WV            
03180000 New River at Bluestone Dam WV            
03180500 Greenbrier River at Durbin WV

*

    *   *
03182000 Knapp Creek at Marlinton WV           *
03182500 Greenbrier River at Buckeye WV

*

* * * * *
03182700 Anthony Creek near Anthony WV            
03183000 Second Creek near Second Creek WV           *
03183500 Greenbrier River at Alderson WV

*

* * * * *
03184000 Greenbrier River at Hilldale WV

*

    *   *
03184500 New River at Hinton WV            
03185000 Piney Creek at Raleigh WV *         *
03185500 New River at Caperton WV            
03186000 New River at Fayette WV            
03186500 Williams River at Dyer WV * * * * * *
03187000 Gauley River at Camden On Gauley WV *   *     *
03187300 North Fork Cranberry River near Hillsboro WV            
03187500 Cranberry River near Richwood WV *     *   *
03189000 Cherry River at Fenwick WV     *     *
03189100 Gauley River near Craigsville WV           *
03189500 Gauley River near Summersville WV a*   a*     *
03189650 Collison Creek near Nallen WV           *
03190000 Meadow River at Nallen WV a*   *     *
03190400 Meadow River near Mount Lookout WV           *
03191500 Peters Creek near Lockwood WV *         *
03192000 Gauley River above Belva WV           *
03193000 Kanawha River at Kanawha Falls WV            
03194700 Elk River below Webster Springs WV a*     *   *
03195000 Elk River at Centralia WV           *
03195500 Elk River at Sutton WV           *
03197000 Elk River at Queen Shoals WV           *
03198500 Big Coal River at Ashford WV * * * * * *
03199000 Little Coal River at Danville WV *   *     *
03200500 Coal River at Tornado WV *     *   *
03201000 Pocatalico River at Sissonville WV *         *
03201410 Poplar Fork at Teays WV            
03202000 Raccoon Creek at Adamsville OH           *
03202400 Guyandotte River near Bailysville WV       *    
03202750 Clear Fork at Clear Fork WV            
03203000 Guyandotte River at Man WV a*   a*      
03203600 Guyandotte River at Logan WV           *
03204000 Guyandotte River at Branchland WV *   *     *
03204500 Mud River near Milton WV *         *
03206600 East Fork Twelvepole Creek near Dunlow WV       *    
03207000 Twelvepole Creek at Wayne WV            
03207020 Twelvepole Creek below Wayne WV            
03207500 Levisa Fork near Grundy VA           *
03208500 Russell Fork at Haysi VA         * *
03208950 Cranes Nest River near Clintwood VA           *
03210000 Johns Creek near Meta KY           *
03211500 Johns Creek near Van Lear KY           *
03212000 Paint Creek at Staffordsville KY           *
03212750 Tug Fork at Welch WV            
03212980 Dry Fork at Beartown WV            
03213000 Tug Fork at Litwar WV *   *     *
03213500 Panther Creek near Panther WV *         *
03213700 Tug Fork at Williamson WV *     *    
03214000 Tug Fork near Kermit WV a* a* a* a* a* *
03214500 Tug Fork at Kermit WV            
03215500 Blaine Creek at Yatesville KY           *

a Station record was lengthened using a nearby station for this analysis.

The minimum flows for some stations located on the same stream and with drainage areas within 25 percent of one another were combined to increase record lengths. The 25- percent criterion was determined as the maximum difference between combined stations—at the drainage areas considered—where the unit minimum flows were approximately equal. The values for the station having the shorter period of record were transferred to the station having the longer period of record. The minimum flows for the station having the shorter period of record were divided by the respective drainage area and multiplied by the drainage area of the station having the longer period of record. Values for the station having the longer period of record were used when the combination of records resulted in more than one value for a particular year. Minimum flows for the following stations in West Virginia were combined: Cheat River near Pisgah (station number, 03071000; drainage area, 1,354 mi2) was lengthened using near Morgantown (03071500, 1,380 mi2); Bluestone River near Pipestem (03179000, 395 mi2) was lengthened using at Lilly (03179500, 438 mi2); New River at Caperton (03185500, 6,826 mi2) was lengthened using at Fayette (03186000, 6,850 mi2); Gauley River near Summersville (03189500, 680 mi2) was lengthened using near Craigsville (03189100, 529 mi2) and; Meadow River at Nallen (03190000, 287 mi2) was lengthened using near Mount Lookout (03190400, 365 mi2); Elk River below Webster Springs (03194700, 266 mi2) was lengthened using at Centralia (03195000, 281 mi2); Guyandotte River at Man (03203000, 758 mi2) was lengthened using at Logan (03203600, 833 mi2); and Tug Fork near Kermit (03214000, 1,188 mi2) was lengthened using at Kermit (03214500, 1,280 mi2). Combined records were used for analyzing the minimum flows and were not used to compute other statistics.

The minimum flows were analyzed for the increase in minimum flows around 1970 identified by McCabe and Wolock (2002) and for having patterns of similar flows for different time periods.

Increase in Minimum Flows Around 1970

Stations in West Virginia having a minimum of 5 years of record before 1970 and 5 years after 1969 were investigated to determine whether there was an increase in minimum flows around 1970 as identified by McCabe and Wolock (2002) (table 1). Departures of the minimum flows from the average minimum flows for the period of record were plotted against time for each station and were visually inspected for the increase in minimum flows around 1970.

The visual patterns of the increase in minimum flows around 1970 in the station plots of departures are not uniform throughout the State. Well-defined increases in minimum flows around 1970 are apparent for many station plots statewide, but some station plots show no noticeable increase. Some station plots in the eastern panhandle of the State indicate a well-defined increase in minimum flows around 1972. The plot for Greenbrier River at Alderson (03183500, 1,364 mi2) does not show an increase in minimum flows (fig. 2) such as the one apparent in the plot for the nearby combined stations Bluestone River near Pipestem (03179000, record years 1952–2002, 395 mi2) and at Lilly (03179500, 1910–48, 438 mi2)(fig. 3). The average minimum flows before the 1970 increase were less than the average minimum flows after the 1970 increase at both Greenbrier River at Alderson and the combined Bluestone River near Pipestem and Bluestone River at Lilly, although the difference at Alderson of about 1 ft3 (about 1 percent of the average minimum flow) is insignificant.


Graph showing departure of the minimum flows from the record-period average for Greenbrier River at Alderson, West Virginia.

Figure 2. Departure of the minimum flows from the record-period average for Greenbrier River at Alderson, West Virginia (Vertical line between 1969 and 1970 separates periods described in text).


Graph showing departure of the minimum flows from the record-period average for the combined stations Bluestone River near Pipestem and at Lily, West Virginia.

Figure 3. Departure of the unit minimum flows from the record-period average for the combined stations Bluestone River near Pipestem and at Lilly, West Virginia (Vertical line between 1969 and 1970 separates periods described in text).


The principal cause of the minimum-flow patterns associated with this analysis is probably climate variability. Mining is probably the greatest land-use change affecting low flows in West Virginia. In small drainage basins (drainage areas less than 10 mi2) mining has transferred water between basins sometimes decreasing low flows and sometimes increasing low flows. The net result of underground mining was an increase in ground-water storage that would return to the surface at a lower elevation due to gravity or would return to the surface from mine pumpage. The water may return to the surface in a different drainage basin, thus in small drainage basins sometimes decreasing low flows and sometimes increasing low flows (Puente and Adkins, 1989; Borchers and others, 1991). In small drainage basins, the net result of valley fills from mountaintop mining was an increase in low flows (Wiley and others, 2001). At large drainage basins (drainage areas greater than 100 mi2) the net result from mining should show an increase in low flows because of ground-water storage returning to the surface at a lower elevation from underground mines and the increase in low flows from valley fills. A visual inspection of the pattern in plots of the minimum flows for large drainage basins affected by mining did not show a general increase through time corresponding to an increase in mining through time. The pattern in plots of the minimum flows probably did not show the changes associated with mining because these changes were indistinguishable from more significant affects, probably those associated with climate variability.

Minimum Flows From 1930 Through 2002

The stations used for the 1930–2002 analysis were limited to those in West Virginia with mostly complete records for the longest possible continuous time period. There were 14 stations with no more than a total of 4 years of missing record for the period from1930 through 2002. The 14 stations were equally distributed across the State except for a lack of coverage along the western border with Ohio and the south-west border with Kentucky. The combined record for station Tug Fork near Kermit (03214000) lengthened using at Kermit (03214500) was included to improve the areal distribution along the south-west border, but there are no data available to improve the distribution along the western border. Equally distributed station locations and minimizing use of combined stations are necessary for studying the variability of flow statistics and calculating a regional average of low flows discussed later in this report. The station set consisted of 15 stations with the combined records for Tug Fork near and at Kermit counted as 1 station (table 1). The standardized departure at each station was computed by subtracting the respective average minimum flow for 1930–2002 from the minimum flow at each station and then dividing by the respective standard deviation of the minimum flow. The standardized departures were averaged for all 15 stations for each year (fig. 4).


Grpag showing average standerdized departures of the minimum flows from the record-period average for 1930-2002 for 15 stations in West Virginia.

Figure 4. Average standardized departures of the minimum flows from the record-period average for 1930–2002 for 15 stations in West Virginia. (Vertical lines separate subperiods described in text.)


The change from the general negative departures to positive departures between the 1969 and 1970 climatic years is apparent in fig. 4. The period 1930–42 indicates mostly negative departure. The period 1943–62 indicates variation between positive and negative departures that average slightly less than the mean. The period 1963–69 indicates consistently negative departure and the most negative average of any of the time periods investigated. The period 1970–79 indicates largely positive departure and the most positive average of any of the time periods investigated. Finally, the period 1980–2002 indicates variation between positive and negative departures, with the positive departures that are the most positive of any of the periods investigated and an average positive departure slightly less than the average for 1970–79. The average departure for the years before 1970 is negative, and the average departure for the years after 1969 is positive.

A statistical trend analysis of the minimum flows for the 15 stations was done by use of the Mann-Kendall test for the record periods 1930–2002, 1930–63, 1930–69, 1930–42, 1943–62, 1943–69, 1963–69, 1963–79, 1970-2002, 1970–79, and 1980–2002. An alpha value of 0.0667 was selected so that 1 station out of the 15 would be expected to indicate a trend by chance. No stations indicated a trend for 1943–62, 1970–79, or 1980–2002. Only one station indicated a trend for 1930–69 and 1963–69 (a different station for each period). Only two stations indicated a trend for 1930–42, 1930–63, 1943–69, and 1970–2002 (only one station indicated a trend for two periods). One or two stations indicating a trend is close enough to the one station expected by chance that the conclusion of no trends was supported.

In contrast, statistically significant positive trends were found for all 15 stations for 1963–79 (14 stations at an alpha value of 0.05, and 6 stations at an alpha value of 0.01) and 6 stations for 1930–2002 (5 stations at an alpha value of 0.05, and 4 stations at an alpha value of 0.01). All 15 stations indicating a trend for 1963–79 is expected because the change from negative departures to positive departures around 1970 was visible in plots of departures for many stations across the State. The six stations indicating a positive trend for 1930–2002 were Cacapon River near Great Cacapon (station number 01611500), Shenandoah River at Milliville (01636500), Buffalo Creek at Barrackville (03061500), Big Sandy Creek at Rockville (03070500), Big Coal River at Ashford (03198500), and the combined stations Tug Fork near Kermit (03214000) and at Kermit (03214500). Two stations are located in the eastern panhandle (01611500 and 01636500), two are in the north-central area (03061500 and 03070500), and two are in the southwest area of the State (03198500 and combined stations 03214000 and 03214500). These six stations are distributed across the State, but none is near the east-central area of the State, which has the highest annual precipitation.

The Mann-Kendall test did not indicate a trend for 1970–2002, although the average departures of minimum flows for 1970–79 are greater than the average departures for 1980–2002. The annual variation of selected flow statistics discussed later in this report also indicates decreases in low flows between 1970–79 and 1980–2002. The Mann-Kendall test did not indicate a negative trend for the decrease in the minimum flows between the periods, probably because the trend was sudden and not gradual. The Mann-Kendall test is better suited for detecting monotonic trends.

Minimum Flows From 1930 Through 1969

The stations used in this analysis were limited to those in West Virginia with mostly complete records for the period 1930–69. There are 29 stations (the combined records for Tug Fork near and at Kermit counted as 1 station) with no more than a total of 2 years of missing record for the 1930–69 period (table 1). The standardized departures were computed for the 29 stations and averaged (fig. 5).

The same time periods (1930–42, 1943–62, and 1963–69) show similar patterns of departures as those determined by analyzing the characteristic from 1930 through 2002 (fig. 5). The average departure for 1963–69 is the most negative.


Graph showing average standardized departures of the minimum flows from the record-period average for 1930-1969 stations in West Virginia.

Figure 5. Average standardized departures of the minimum flows from the record-period average for 1930–1969 for 29 stations in West Virginia. (Vertical lines separate subperiods described in text.)


Minimum Flows From 1970 Through 2002

The stations used in this analysis were limited to those in West Virginia with mostly complete records for the period 1970–2002. There are 32 stations (or combined stations counted as 1 station) with no more than a total of 2 years of missing record for the 1970–2002 period (table 1). The standardized departures were computed for the 32 stations and averaged (fig. 6).


Graph showing average standardized departures of the minimum flows from the record-period average for 1970-2002 for 32 stations in West Virginia.

Figure 6. Average standardized departures of the minimum flows from the record-period average for 1970–2002 for 32 stations in West Virginia (Vertical line separate subperiods described in text).


The same time periods (1970–79 and 1980–2002) show similar patterns of departures as those determined by analyzing the characteristic from 1930 through 2002 (fig. 6). The average departure for 1970–79 is the most positive.

Minimum Flows Before 1930

Few West Virginia stations with long periods of records include the period before 1930. Shenandoah River at Millville (01636500) has record starting in 1896 and extending through 2002 (fig. 7) and indicates an increase in minimum flow between the 1971 and 1972 climatic years; however, record is missing from 1910 through 1929. The average positive departures for 1896–1909 are greater than the average departures for 1972–79 and 1972–2002. Greenbrier River at Alderson (03183500) has record from 1897 through 2002 and does not show an increase in minimum flow around 1970 (fig. 2). The average positive departures for 1896–1909 and 1896–1929 are greater than the average departures for the periods 1970–79 and 1970–2002. The analysis for these two stations indicates that there were probably periods in West Virginia between 1896 and 1930 when minimum flows were greater than during any periods between 1930 and 2002.


Graph showing departure of the minimum flows from the record-period average for Shenandoah River at Midville, West Virginia.

Figure 7. Departure of the minimum flows from the record-period average for Shenandoah River at Millville, West Virginia.


The Shenandoah River at Millville and Greenbrier River at Alderson are most likely representative of the regional pattern of minimum flows because the log10-transformed flow values are fairly well correlated with concurrent log10-transformed flow values at other stations. The correlation coefficient of minimum flows at Shenandoah River at Millville with minimum flows at Kanawha River at Kanawha Falls (03193000) is 0.75 for the record period 1878–1948, sharing 35 years of concurrent record. Correlation coefficients of 0.84 and 0.82, respectively, were found for minimum flows at Greenbrier River at Alderson and minimum flows at Cheat River near Parsons (03069500), record period 1914–2002 (89 years of concurrent record), and with minimum flows at Tygart Valley River at Belington (03051000), record period 1909–2002 (94 years of concurrent record).

Variability of Flow Statistics

Several streamflow statistics were computed for 15 stations (combined records for Tug Fork near and at Kermit counted as 1 station) to study the variability of determined values for 1930–2002. The 15 stations are the same as those used for the minimum-flow analysis for 1930–2002 (table 1). The annual and seasonal 1Q10, 7Q10, 30Q5, 1B3, 4B3, and the EPA harmonic-mean flows were computed for 1930–2002, 1930–42, 1943–62, 1963–69, 1970–79, and 1980–2002.

Comparison of Annual Statistics

The values of the selected annual statistics (climatic year) for the 15 stations were averaged and compared to values computed for 1930–2002 to assess variability (table 2). Differences of the average values for the period 1930–42 compared to the average values for the period 1943–62 mostly increase; differences include both increases and decreases between 1943–62 and 1963–69; differences all increase between 1963–69 and 1970–79, and all decrease between 1970–79 and 1980–2002. Generally, the relative differences in values between successive periods follow the trend of the departures of the minimum flows (fig. 4).

Table 2. Average differences between selected annual statistics computed for 1930–2002 and the statistics computed for the indicated record periods for 15 stations in West Virginia.

[Station numbers for the 15 stations are 01606500, 01608500, 01611500, 01636500, 03051000, 03053500, 03061500, 03066000, 03069500, 03070500, 03182500, 03183500, 03186500, 03198500, and combined stations 03214000 and 03214500; a negative value means the average for the indicated record period is less than the average for 1930–2002; a positive value means the average for the indicated record period is greater than the average for 1930–2002; EPA, U.S. Environmental Protection Agency]

Streamflow statistic Difference for the indicated period, in percent
1930–42 1943–62 1963–69 1970–79 1980–2002
1-day 10-year hydrologically based low flow (1Q10) -23.7 -11.2 5.4 187.0 52.3
7-day 10-year hydrologically based low flow (7Q10) -20.6 -13.6 2.4 182.8 47.7
30-day 5-year hydrologically based low flow (30Q5) -9.8 -12.7 -19.2 115.1 24.1
1-day 3-year biologically based low flow (1B3) -36.9 -10.7 9.2 200.7 67.4
4-day 3-year biologically based low flow (4B3) -32.1 -13.5 8.9 190.3 58.9
EPA harmonic mean flow -21.0 -7.1 -15.2 90.7 31.6

The increases and decreases between values for 1943–62 and 1963–69 are inconsistent with the trend of the departures of the minimum flows (fig. 4), where a marked decrease between the periods is apparent in the plot. The increases are for the values of lower flows (1Q10, 7Q10, 1B3, and 4B3), whereas the decreases are for higher flows (30Q5 and the EPA harmonic-mean flow).

No consistent trend was found between statistics for lower flows and those for higher flows. For 1930–42, the absolute differences of values for the lower flows are equal or greater than the absolute differences for higher flows. For 1943–62, the absolute differences are approximately equal. In contrast, for 1970–79 and 1980–2002, the differences of values for the lower flows are about twice the differences for the higher flows.

There is a consistent trend in the statistics for the hydrologically based flows 1Q10 and 7Q10 and the biologically based flows 1B3 and 4B3: absolute differences for hydrologically based flows are approximately equal to or smaller than those for biologically based flows for all periods.

The variability of the differences between annual statistics computed for each subperiod compared to the values computed for 1930–2002 decreases with increasing flows; the values in table 2 get closer to zero when comparing the values for 1Q10, 7Q10, 1B3, and 4B3 to the higher flow values for 30Q5 and the EPA harmonic-mean flow. The values for 1Q10, 7Q10, 1B3, and 4B3 range from -36.9 to 200.7 percent for the average of stations for each period from the values computed for 1930–2002, and the values for 30Q5 and the EPA harmonic-mean flow range from -21.0 to 115.1 percent (table 2). The values for 1Q10, 7Q10, 1B3, and 4B3 range from -93.9 to 582.5 percent for the individual stations for each period from the values computed for 1930–2002, and the values for 30Q5 and the EPA harmonic-mean flow range from -62.3 to 281.2 percent (table 3). Table 3 contains no values for the period 1930-42 for the combined station Tug Fork near Kermit (03214000) and at Kermit (03214500) because the combined station was only used for analyzing the minimum flows and was not used to compute other statistics, and because there were not sufficient years of record at either station to make an estimate representative of the period.

Table 3. Differences between selected annual statistics computed for 1930–2002 and the statistics computed for the indicated record periods for 15 stations in West Virginia.

[Station numbers for the 15 stations are 01606500, 01608500, 01611500, 01636500, 03051000, 03053500, 03061500, 03066000, 03069500, 03070500, 03182500, 03183500, 03186500, 03198500, and combined stations 03214000 and 03214500; a negative value means the average for the indicated record period is less than the average for 1930–2002; a positive value means the average for the indicated record period is greater than the average for 1930–2002]

Station number Difference for the indicated period, in percent
1930–42 1943–62 1963–69 1970–79 1980–2002
1-day 10-year hydrologically based low flow (1Q10)
01606500 -2.8 4.2 -17.7 26.5 4.4
01608500 -3.5 6.1 -28.2 62.0 10.8
01611500 -1.8 7.5 -31.4 19.9 18.3
01636500 -21.5 15.5 -19.0 23.6 10.8
03051000 -56.5 16.0 74.6 524.4 7.0
03053500 -56.8 -17.8 33.5 366.3 45.7
03061500 -66.7 -20.7 50.2 351.5 149.1
03066000 4.6 -32.0 7.8 98.1 14.4
03069500 -24.9 -18.9 -11.6 170.1 25.1
03070500 -7.2 -56.3 31.8 217.4 93.8
03182500 -35.4 7.3 -28.9 115.6 28.6
03183500 -13.3 -2.1 4.3 70.5 -1.9
03186500 -1.1 -30.4 23.3 312.8 -6.3
03198500 -45.3 -37.7 -28.2 339.7 250.0
a 03214000 and 03214500 No value b -8.6 b 20.5 b 107.0 c 134.3
7-day 10-year hydrologically based low flow (7Q10)
01606500 -2.1 2.6 -19.2 27.2 5.7
01608500 -5.5 5.7 -26.1 59.6 11.6
01611500 -2.2 5.1 -29.4 21.0 18.1
01636500 -7.1 14.0 -24.6 14.0 4.4
03051000 -53.9 -4.9 55.7 582.5 24.3
03053500 -56.3 -20.2 33.3 387.1 45.6
03061500 -59.0 -20.1 41.5 269.0 98.7
03066000 2.2 -26.6 -7.7 101.7 13.6
03069500 -25.2 -23.0 -4.4 182.3 30.6
03070500 -7.5 -56.2 30.5 213.9 98.5
03182500 -26.9 0.9 -26.9 117.2 19.0
03183500 -14.3 -4.5 3.4 63.1 3.1
03186500 12.0 -34.0 19.5 302.9 -3.2
03198500 -42.3 -36.2 -27.1 293.1 217.8
b 03214000 and 03214500 No value b -5.9 b 17.6 b 107.5 c 127.7
30-day 5-year hydrologically based low flow (30Q5)
01606500 -0.2 4.8 -19.0 25.7 2.8
01608500 -1.6 4.4 -25.2 39.3 4.7
01611500 -3.0 -0.4 -28.5 30.0 12.1
01636500 -1.5 6.9 -23.2 13.9 3.0
03051000 -21.6 -21.9 -18.0 281.2 9.2
03053500 -35.3 -23.8 -5.3 215.2 20.2
03061500 -50.6 -19.6 -8.0 220.6 58.1
03066000 7.6 -25.2 -16.6 93.6 11.2
03069500 2.3 -22.7 -14.4 115.3 11.6
03070500 -14.9 -35.4 -37.2 134.8 54.2
03182500 0.7 5.9 -37.1 65.5 2.1
03183500 2.2 2.3 -10.0 53.6 -2.1
03186500 11.1 -26.1 -20.8 188.7 0.9
03198500 -32.2 -34.4 -27.6 149.2 97.3
a 03214000 and 03214500 No value b -5.6 b 3.2 b 100.4 c 76.1
1-day 3-year biologically based low flow (1B3)
01606500 -6.3 5.7 -10.2 34.5 1.8
01608500 -8.2 4.9 -11.2 85.9 33.1
01611500 -3.0 2.4 -27.0 18.6 24.1
01636500 -21.1 21.4 -28.6 21.7 18.1
03051000 -93.9 -7.1 75.0 541.9 -20.6
03053500 -92.7 -11.0 32.2 265.7 12.7
03061500 -60.0 -10.9 60.0 480.0 223.6
03066000 -15.8 -26.3 12.5 101.8 21.8
03069500 -59.5 -29.4 -14.5 159.9 33.5
03070500 -43.8 -42.6 24.9 145.4 71.1
03182500 -42.3 0.0 -16.5 153.6 36.4
03183500 -38.0 -13.3 4.0 61.8 2.0
03186500 21.2 -25.6 34.6 384.0 39.1
03198500 -52.9 -26.5 -30.0 458.8 367.6
a 03214000 and 03214500 No value b -2.7 b 32.4 b 97.3 c 147.5
4-day 3-year biologically based low flow (4B3)
01606500 -8.5 6.3 -12.1 34.1 8.5
01608500 -4.3 6.8 -9.7 79.3 36.8
01611500 -0.5 3.4 -25.3 25.5 24.0
01636500 -13.4 17.2 -30.9 13.4 12.2
03051000 -83.4 -10.0 66.6 580.0 -20.0
03053500 -91.3 -17.7 15.3 360.0 20.7
03061500 -40.5 -12.7 51.9 350.6 155.7
03066000 -7.1 -23.5 7.9 114.0 22.2
03069500 -62.2 -38.7 8.9 164.6 23.8
03070500 -30.0 -52.3 33.6 105.5 52.6
03182500 -37.4 -6.7 -6.7 145.0 55.8
03183500 -39.5 -14.4 2.1 68.9 2.1
03186500 16.8 -30.2 34.2 326.7 23.3
03198500 -48.6 -30.4 -35.1 383.5 305.7
a 03214000 and 03214500 No value b -0.3 b 32.3 b 103.3 c 159.9
U.S. Environmental Protection Agency harmonic-mean flow
01606500 -5.6 0.9 -26.2 22.3 5.6
01608500 -7.4 0.0 -30.1 29.6 8.2
01611500 -10.7 -1.3 -24.5 35.8 6.3
01636500 -7.3 3.3 -27.1 23.6 4.1
03051000 -57.7 16.4 11.0 222.2 46.1
03053500 -62.3 7.8 30.4 244.3 97.2
03061500 -49.9 -11.9 -28.9 156.3 56.3
03066000 -7.2 -15.9 -17.2 49.1 15.1
03069500 -23.1 -9.0 -16.2 54.4 18.8
03070500 17.4 -45.4 -19.2 159.0 78.5
03182500 -18.8 2.8 -29.9 45.1 10.4
03183500 -14.7 1.6 -19.9 40.6 3.5
03186500 -7.0 -23.5 -8.5 121.4 10.4
03198500 -39.9 -21.5 -19.2 93.5 72.0
a 03214000 and 03214500 No value b -10.1 b -2.7 b 63.4 c 41.3

a 1930–2002 period estimated from record for 1936–85 at Tug Fork near Kermit (03214000).

b Computed from record for Tug Fork near Kermit (03214000).

c Estimated from record for 1986–2002 at Tug Fork at Kermit (03214500).

An increase in departures around 1970 is not obvious in the plot of departures for Greenbrier River at Alderson (03183500) (fig. 2), but values for the selected annual statistics indicate an increase between 1963–69 and 1970–79. The greatest difference was found for 1970–79, where the selected statistics are between 40.6 and 70.5 percent greater than those for 1930–2002 (table 3).

Comparison of Seasonal Statistics

Selected statistics were computed for January 1 through March 31 (winter), April 1 through June 30 (spring), July 1 through September 30 (summer), and October 1 through December 31 (fall). The average differences (table 4) and individual-station differences (table 5 at back of report) of the selected statistics were compared to values computed for 1930–2002 for the 15 stations to measure variability.

Table 4. Average differences between selected seasonal statistics computed for 1930–2002 and the statistics computed for the indicated record periods for 15 stations in West Virginia.

[Winter, January 1–March 31; spring, April 1–June 30; summer, July 1–September 30; fall, October 1–December 31; station numbers for the 15 stations are 01606500, 01608500, 01611500, 01636500, 03051000, 03053500, 03061500, 03066000, 03069500, 03070500, 03182500, 03183500, 03186500, 03198500, and combined stations 03214000 and 03214500; a negative value means the average for the indicated record period is less than the average for 1930–2002; a positive value means the average for the indicated record period is greater than the average for 1930–2002]

Season Difference for the indicated period, in percent
1930–42 1943–62 1963–69 1970–79 1980–2002
1-day 10-year hydrologically based low flow (1Q10)
Winter -9.7 6.0 -11.5 69.4 -2.6
Spring -12.5 35.7 -29.5 32.4 9.2
Summer -24.8 -6.5 -3.6 175.4 44.8
Fall -26.2 -18.8 6.3 167.2 62.2
7-day 10-year hydrologically based low flow (7Q10)
Winter -12.2 -4.4 -17.3 58.5 0.1
Spring -17.6 19.5 -29.2 27.1 3.4
Summer -21.8 -8.3 -6.0 176.2 39.2
Fall -25.6 -20.4 10.6 140.4 55.3
30-day 5-year hydrologically based low flow (30Q5)
Winter -19.2 2.3 -31.4 31.7 6.5
Spring -18.7 13.1 -34.3 5.1 6.8
Summer -12.5 -6.3 -29.2 85.4 20.0
Fall -25.6 -17.5 -16.5 104.6 22.9
1-day 3-year biologically based low flow (1B3)
Winter -11.4 -4.2 1.7 73.8 5.8
Spring -30.2 15.7 4.3 4.7 57.9
Summer -35.0 -5.4 0.8 170.2 50.8
Fall -35.7 -15.1 7.8 207.7 72.2
4-day 3-year biologically based low flow (4B3)
Winter -8.1 -4.4 -13.2 59.1 5.1
Spring -24.3 18.6 3.0 0.6 53.7
Summer -33.2 -5.8 -2.8 159.3 39.1
Fall -40.0 -20.3 7.3 170.2 54.1
U.S. Environmental Protection Agency harmonic-mean flow
Winter -5.7 5.5 -19.5 37.9 -1.9
Spring -25.3 4.0 -14.9 3.8 28.6
Summer -21.9 1.0 -27.9 86.3 31.8
Fall -18.3 -14.3 2.9 142.5 41.0

Generally, the relative average difference in values between successive fall periods (table 4) follows the trend of the departures of the minimum flows (fig. 4) because the minimum flows commonly take place in the fall. The average differences of values for all seasons for all statistics are negative for 1930–42 (table 4); differences for the individual stations range from -95.7 to 43.3 percent (table 5 at back of report). The average differences of values are mixed for 1943–62 and 1963–69; differences for the individual stations range from -86.9 to 231.2 percent. The average differences for values of 30Q5 are negative for all seasons, and those for 1B3 are positive for all seasons for 1963–69. The average differences of values for all seasons for all statistics are positive for 1970–79; differences for the individual stations range from -44.6 to 683.6 percent. The average differences of values for the summer and fall for 1970–79 are the greatest for all periods, ranging from 85.4 to 207.7 percent for all statistics. The average differences of values for the spring for 1970–79 vary between the biologically based flows (range, 0.6 to 4.7 percent) and hydrologically based flows (range, 5.1 to 32.4 percent). The average differences of values for all statistics are less for 1980–2002 than for 1970–79 except for spring values of 30Q5, biologically based flows, and the EPA harmonic-mean flow. The differences of values for all seasons for all statistics for the individual stations range from -45.5 to 603.4 percent for 1980–2002.

Karl and Knight (1998) found that the increases in low flows around 1970 coincide with increased rainfall, primarily in the fall (September 1–November 30) when the lowest streamflows typically occur. As table 4 indicates, the average differences for the period 1970–79 in the summer (July 1–September 30) and fall (October 1–December 31) are the greatest differences for any of the periods investigated. The results of this study are similar to the findings by Karl and Knight (1998).

Comparison Between Hydrologically Based and Biologically Based Low Flows

The 1Q10 and 1B3 were found to be nearly equal, on average, in an analysis of 60 streams across the United States by the U.S. Environmental Protection Agency (1986). The 7Q10 and 4B3 were also found to be nearly equal.

In this study, averaged-station comparisons (table 6) and individual-station comparisons (table 7) between 1Q10/1B3 and 7Q10/4B3 were made for 1930–2002 for the 15 stations. The 1B3 and 4B3 average 6.2- and 7.9-percent less than the 1Q10 and 7Q10 (table 6), respectively; differences for the individual stations range from 28.5 percent less to 13.6 percent greater (table 7). Generally, the biologically based flow was less than the hydrologically based flow in the winter and fall, greater in the spring, and varied among the individual stations during the summer.

Table 6.— Average annual and seasonal differences between the 1-day 10-year hydrologically based and 1-day 3-year biologically based low-flow frequencies and between the 7-day 10-year hydrologically based and 4-day 3-year biologically based low-flow frequencies computed for 1930–2002 for 15 stations in West Virginia.

[Winter, January 1–March 31; spring, April 1–June 30; summer, July 1–September 30; fall, October 1–December 31; 1Q10, 1-day 10-year hydrologically based low-flow frequency; 1B3, 1-day 3-year biologically based low-flow frequency; 7Q10, 7-day 10-year hydrologically based low-flow frequency; 4B3, 4-day 3-year biologically based low-flow frequency; negative numbers indicate the biologically based flow is less than the hydrologically based flow, and positive numbers indicated the biologically based flow is greater than the hydrologically based flow; station numbers for the 15 stations are 01606500, 01608500, 01611500, 01636500, 03051000, 03053500, 03061500, 03066000, 03069500, 03070500, 03182500, 03183500, 03186500, 03198500, and combined stations 03214000 and 03214500]

Compared streamflow statistics Average difference, in percent
Annual Seasonal
Winter Spring Summer Fall
1Q10 and 1B3 -6.2 -23.1 59.9 2.8 -23.9
7Q10 and 4B3 -7.9 -20.9 49.6 4.1 -21.9

Table 7. Annual and seasonal differences between the 1-day 10-year hydrologically based and 1-day 3-year biologically based low-flow frequencies and between the 7-day 10-year hydrologically based and 4-day 3-year biologically based low-flow frequencies computed for 1930–2002 for 15 stations in West Virginia.

[Winter, January 1–March 31; spring, April 1–June 30; summer, July 1–September 30; fall, October 1–December 31; 1Q10, 1-day 10-year hydrologically based low-flow frequency; 1B3, 1-day 3-year biologically based low-flow frequency; 7Q10, 7-day 10-year hydrologically based low-flow frequency; 4B3, 4-day 3-year biologically based low-flow frequency; negative numbers indicate the biologically based flow is less than the hydrologically based flow, and positive numbers indicated the biologically based flow is greater than the hydrologically based flow; station numbers for the 15 stations are 01606500, 01608500, 01611500, 01636500, 03051000, 03053500, 03061500, 03066000, 03069500, 03070500, 03182500, 03183500, 03186500, 03198500, and combined stations 03214000 and 03214500]

Station number Difference between annual statistics, in percent Difference between seasonal statistics, in percent
Winter Spring Summer Fall
1Q10 and 1B3 7Q10 and 4B3 1Q10 and 1B3 7Q10 and 4B3 1Q10 and 1B3 7Q10 and 4B3 1Q10 and 1B3 7Q10 and 4B3 1Q10 and 1B3 7Q10 and 4B3
01606500 -4.2 -6.2 -24.2 -27.8 31.7 34.2 -2.9 -3.3 -7.9 -7.8
01608500 -12.3 -12.0 -30.3 -32.1 37.3 38.4 -9.9 -7.5 -17.2 -11.4
01611500 -0.6 -2.0 -25.4 -19.5 30.9 28.1 -0.2 -1.8 -9.2 -6.3
01636500 0.4 -4.0 -16.9 -17.0 16.9 11.6 2.6 -4.4 7.4 -1.1
03051000 3.4 -8.0 -17.2 -11.5 99.0 73.5 40.7 32.9 -18.3 -34.2
03053500 7.9 9.2 -16.7 -11.3 83.5 66.5 -4.1 28.0 -34.1 -31.4
03061500 -14.5 -23.1 -31.9 -39.0 75.5 53.1 -5.8 -2.4 -20.9 -33.7
03066000 -8.6 -21.1 -14.4 -7.8 54.3 42.3 6.0 -7.0 -36.8 -36.3
03069500 -7.5 0.2 -1.4 -5.3 61.4 51.0 0.7 0.2 -17.6 -25.5
03070500 2.6 13.6 -17.0 -13.0 102.3 88.3 40.1 26.8 -31.7 -21.7
03182500 -11.7 -16.7 -23.3 -24.2 73.0 57.6 -7.8 -2.5 -37.6 -17.4
03183500 2.2 -0.1 -37.6 -32.0 71.9 56.4 2.4 1.1 -16.8 -5.7
03186500 -11.8 -8.6 -17.0 -9.6 70.1 65.4 2.1 4.5 -42.3 -41.7
03198500 -28.5 -28.2 -33.0 -27.6 73.2 64.0 -20.0 -7.6 -43.6 -28.6
a 03214000 and 03214500 -10.0 -11.8 -40.7 -35.2 17.3 12.9 -1.1 4.4 -31.3 -25.0

a 1930–2002 period estimated from record for 1936–85 at Tug Fork near Kermit (03214000).

The results of this study are consistent with the findings by the U.S. Environmental Protection Agency (1986) for the analysis of hydrologically and biologically based flows. There were no statistics computed seasonally in the study by the U.S. Environmental Protection Agency that could be compared to the results from this study.

Selected Flow Statistics Representative of 1930–2002

The sample of available streamflow records is not representative of the entire population of streamflow records over the time period encompassing the operation of all the stations. Therefore, estimating equations developed by using the entire sample of station records would not be representative of the overall period when stations were operating. Estimating equations should be developed by use of station records that are representative of streamflows during a particular period of interest. These representative station records could not be acquired by means of record-extension techniques; rather, they were acquired for this analysis by way of a purposeful sampling (criterion based for this application) of the available station records.

Record periods for unregulated stations throughout a state or other large area differ because of differing times that stations were operating at particular locations. The number of active stations in a given area changes through time because of budget constraints, interests in particular hydrologic investigations, and stream regulation. The number of stations in West Virginia was about 5 between 1900 and 1910, increased to about 20 between 1910 and 1920, increased to about 40 in the early 1930s, increased to about 95 in the late 1940s, was about 95 between 1950 and 1960, increased to about 110 around 1970, remained at 110 through the early 1980s, decreased to about 70 in the middle 1980s (Runner and others, 1989, fig.1), and decreased to about 60 in 2002. The greatest number of stations was operating after a sudden increase in minimum flows was observed around 1970, and many fewer stations were operating during the 1930s, during a significant drought. Therefore, the entire sample of station records is not random and does not represent the entire population; generally, the entire sample of station records has a positive bias over the period encompassing the operation of the stations.

Record periods in West Virginia can be divided into three general groups based on length: those near the length of the overall time period encompassing the operation of the stations, those near the median length of record periods for all stations, and those near the length of the 10-year minimum record period. Record periods near the length of the overall time period will be representative of the entire population. Record periods near the median length of record periods for all stations will be biased toward the period during the 1970s when minimum flows were much greater than average and biased away from the 1930s when there was a significant drought, if the record periods are equally distributed across the entire sample of station records. Bias in record periods near the 10-year minimum will be similar to those near the median length of record periods for all stations if they are equally distributed across the entire sample of station records. Some record periods near the 10-year minimum will be during consistently wet or dry periods and will be significantly different than the average of the entire population.

Log10-transformed minimum flows for the entire record period at the 15 stations with record during the period 1930–2002 (fig. 4) and five stations from outside the State were correlated with log10-transformed minimum flows for the entire record period at the remaining stations to study record-extension capabilities. Four stations were in Virginia: North Fork Shenandoah River at Cootes Store (01632000), Goose Creek near Leesburg (01644000), Dunlap Creek near Covington (02013000), and Russell Fork at Haysi (03208500). One station was in Ohio; Little Beaver Creek near East Liverpool (03109500). Correlation coefficients of 0.80 or greater were considered reliable for extending the station record at the remaining stations to the period 1930–2002. There were 47 stations in West Virginia with correlation coefficients of 0.80 or greater, but none of these stations were in the northern panhandle and only 4 stations were within 50 mi of the Ohio River along the western border of the State. Although records could be extended at the 47 stations, the areal distribution of stations was insufficient for developing estimating equations for ungaged-stream locations.

A criterion-based sampling (Goetz and LeCompte, 1984, p. 77) of the entire sample of station records can provide record periods representative of a defined time period. The criterion would reduce the influence caused particularly by the positive bias inherent in the entire sample of station records but also by the bias resulting when individual station records were collected only during a consistently wet or dry period. The longest time period with a sufficient number of active stations well distributed across the State was needed to develop a criterion for sampling. This period also should include a significant drought. The period 1930–2002 has record periods at 15 stations distributed across the State and includes the drought of the 1930s.

Correlation between the log10-transformed average minimum flow and the log10-transformed 1Q10, 7Q10, 30Q5, 1B3, and 4B3, and the EPA harmonic-mean flows for 110 stations (listed in table 1) having a minimum of 10 years of low-flow record in West Virginia resulted in correlation coefficients ranging from 0.987 to 0.998. The high correlation between the average minimum flow and the selected statistics indicates that the minimum flow can be used as a surrogate for statistical analysis. A sampling criterion based on record periods determined from analyzing the minimum flow will be applicable to low-flow statistics. A sampling criterion that the average minimum flow of the record period is nearly equal to the average minimum flow for 1930–2002 will provide representative record periods of the entire population for 1930–2002.

The standardized departures of the minimum flows for the 15 stations during 1930–2002 (fig. 4) were combined with the standardized departures of five stations outside the State (identified above) to determine regional subsets of record periods that could represent 1930–2002.

Principal component and correlation analyses were done on the standardized departures of the 20 stations. Three groups of stations representing three regions of the State were identified, and three stations were removed from consideration in the regional analysis. The three regions are identified in this report as the Lower Appalachian Plateaus, the Upper Appalachian Plateaus, and the Eastern Panhandle (fig. 8). The main stem of the Cheat, Monongahela, and Elk Rivers downstream from the boundary between the Lower Appalachian Plateaus and Upper Appalachian Plateaus are part of the Upper Appalachian Plateaus, but the tributaries to these Rivers downstream from the boundary are part of the Lower Appalachian Plateaus. Greenbrier River at Alderson (03183500) was removed from consideration in the Upper Appalachian Plateaus because it was on the same stream and highly correlated with Greenbrier River at Buckeye (03182500) (correlation coefficient of 0.92). South Branch Potomac River near Springfield (01608500) was removed from consideration in the Eastern Panhandle because it was on the same stream and highly correlated with South Branch Potomac River near Petersburg (01606500) (correlation coefficient of 0.95). Dunlap Creek near Covington, Va. (02013000) was removed from the analysis because it was grouped with the Eastern Panhandle, although it is closer to the Upper Appalachian Plateaus; moreover, its unusually high minimum flow for 1930, which is apparently accurate (D.C. Hayes, U.S. Geological Survey, oral commun., September 10, 2004), is inconsistent with concurrent minimum flows at other stations in the study area.


Map showing U.S. Geological Survey streamflow-gaging stations used to determine three regions of similar minimum flow patterns: Lower Appalachian Plateaus, Upper Appalachian Plateaus, and Eastern Panhandle.

Figure 8. U.S. Geological Survey streamflow-gaging stations used to determine three regions of similar mimimum flow patterns: Lower Appalachian Plateaus, Upper Appalachian Plateaus, and Eastern Panhandle.


Generally, the Lower Appalachian Plateaus has less annual precipitation—between about 40 and 50 in.—than the Upper Appalachian Plateaus, where the annual precipitation is between about 50 and 60 in. (U.S. Department of Agriculture, Natural Resources Conservation Service, 2004). The exception is the Greenbrier River in the Upper Appalachian Plateaus where annual total precipitation is about 42–48 in.

The standardized departures were averaged for the three regions, and plots of the departures (figs. 9–11) show the increase around 1970 is most apparent in the Lower Appalachian Plateaus. The increase in minimum flows around 1970 and the greater-than-average minimum flows for 1970–79 probably dissipated from west to east, as evidenced by the absence of strong correlation between stations in the Lower Appalachian Plateaus and the difference between patterns of the departures for the Lower and Upper Appalachian Plateaus (figs. 9 and 10). There was also probably a north-to-south difference in minimum flows within the Lower Appalachian Plateaus, as evidenced by the absence of strong correlation between stations in that region. The east-to-west and north-to-south variability in minimum flows in the Lower Appalachian Plateaus reduced the effectiveness of record-extension techniques. The seasonal increase in atmospheric moisture after about 1970 (Karl and Knight, 1998) could have resulted in storms having clouds with greater densities. Precipitation that previously did not fall until reaching the area of the State where mean annual precipitation is the greatest could have began falling sooner, resulting in greater relative increases in minimum flows in the Lower Appalachian Plateaus (fig. 9) and less or no relative increases in minimum flows in the Upper Appalachian Plateaus (fig. 10). This meteorological hypothesis could help explain why the plot of departures for the Greenbrier River at Alderson (03183500) did not show the increase in minimum flows around 1970 (fig. 2) evident in the plot of departures for the nearby combined stations Bluestone River near Pipestem (03179000) and Bluestone River at Lilly (03179500)(fig. 3). The Greenbrier River Basin receives annual precipitation of about 42–48 in. and is within a significant rain shadow caused by mountainous terrain (annual precipitation reaches about 60 in. on the windward side), whereas the Bluestone River Basin receives annual precipitation of about 38–40 in. and is not within as significant of a rain shadow (annual precipitation reaches only about 46 in. on the windward side). There is little or no increase in minimum flows for the Greenbrier River because the increased moisture was probably depleted from crossing the mountainous terrain before reaching the basin, unlike the situation for the Bluestone River. The Upper Appalachian Plateaus is significantly different from the other regions in that standardized departures for the period 1970–79 are much lower, close to the average for 1930–2002. Also, none of the stations indicating a trend for 1930–2002 by use of the Mann-Kendall test (discussed earlier in this report) are in the Upper Appalachian Plateaus Region.


Graph showing average standardized departures of the minimum flows from the record-period average for 1930-2002 for six stations in the Lower Appalachian Plateaus region.

Figure 9. Average standardized departures of the minimum flows from the record-period average for 1930–2002 for six stations in the Lower Appalachian Plateaus region.


Graph showing average standardized departures of the minimum flows from the record-period average for 1930-2002 for six stations in the Upper Appalachian Plateaus region.

Figure 10. Average standardized departures of the minimum flows from the record-period average for 1930–2002 for six stations in the Upper Appalachian Plateaus region.


Graph showing average standardized departures of the minimum flows from the record-period average for 1930-2002 for five stations in the Eastern Panhandle region.

Figure 11. Average standardized departures of the minimum flows from the record-period average for 1930–2002 for five stations in the Eastern Panhandle region.


The sampling criterion was based on determining where the average minimum flow of a record period is nearly equal to that for 1930–2002 in each region. The standardized departures for every 10-year or greater record period between 1930 and 2002 were averaged and compared to the standard deviation of the standardized departures for 1930–2002 for the three regions. The subset of record periods with average departures within 5 percent of the standard deviation of the departures were determined to be representative of 1930–2002 for the three regions (figs. 12–14). The subset of record periods may account for changes in low flow associated with climate variability, but changes in land use—particularly associated with mining—probably remain.

The Lower Appalachian Plateaus, with six stations, has the most restrictive subset of record periods (fig. 12) compared to the other regions (figs. 13–14). There are no 10-year or greater record periods beginning after 1965 or ending before 1974. The record periods for the Lower Appalachian Plateaus are roughly balanced around about 1970 when there was an increase from negative to positive departures (fig. 9). The Upper Appalachian Plateaus has the least restrictive subset of record periods (fig. 13), with the subset of record periods that include the maximum possible beginning year, 1993. The Eastern Panhandle does not have any subset of record periods beginning after 1980.


Plot showing record periods for the Lower Appalachian Plateaus region for which the average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930-2002. (Six stations in West Virginia, Ohio, and Virginia; open circle indicates negative departure; solid trianagle indicates positive departure.

Figure 12. Record periods for the Lower Appalachian Plateaus region for which the average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930–2002 (Six stations in West Virginia, Ohio, and Virginia; open circle indicates negative departure; solid triangle indicates positive departure).


Plots showing record periods for the Upper Appalachian Plateaus region for which the average departures was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930-2002.

Figure 13. Record periods for the Upper Appalachian Plateaus region for which the average departure was within 5 percent of the standard deviation of the standardized departures of the mimimum flows for 1930–2002 (Six stations in West Virginia; open circle indicates negative departure; solid triangle indicates positive departure.


Plot showing record periods for the Eastern Panhandle region for which the average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930–2002.

Figure 14. Record periods for the Eastern Panhandle region for which the average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930–2002 (Five stations in West Virginia; open circle indicates negative departure; solid triangle indicates positive departure).


The subsets of record periods for the three regions were used to determine subset record periods for all stations in West Virginia. Subset record periods for all stations were selected from the subset of record periods determined by the maximum record length with the minimum departure for the appropriate region (figs. 12–14; tables 8–10, near the end of this report). The dark shaded areas in tables 8–10 indicate 10-year record periods not feasible through 2002, and the light shaded area in table 8 is for the first example presented below.

The subset record period for a particular station can be determined by means of the appropriate regional table. For example, if a station is in the Lower Appalachian Plateaus and the station has a record length of 26 years beginning in climatic year 1949, all record periods of 10 years or more between 1949 and 1974 are feasible. The feasible record periods can be found in table 8 by locating the table entry where the first year is 1949 and the years of record are 26. The field defined by every table entry to the left and increasing by one entry down with each entry to the left indicates the feasible record periods, and these entries are lightly shaded in table 8 for this example. The record period representing 1930–2002 is either the period with the maximum number of record years or the period with the tabled average departure nearest to zero when more than one period is available for the maximum number of years. This example indicates that the maximum number of years is 19 beginning in 1956, or a subset record period of 1956–74, because the near-zero value of -0.034 is tabulated as the feasible record period having the maximum number of record years.

There is no subset record for Leading Creek near Glenville (03152500). There are 13 years of record 1939–51, and the station is located in the Lower Appalachian Plateaus (figs. 1 and 8). The feasible record periods can be found in table 8 by locating the table entry where the first year is 1939 and the years of record are 13; there are no values in the field defined by every table entry to the left and increasing by one entry down with each entry to the left. There is no subset record period because there are no values in the feasible-record field.

Selected statistics were computed for all stations where all or some part of the record period was included in the subset of record periods. Only continuous record periods were considered; therefore, a break in the record period could result in more than one selected record period for a station. The longest selected record period was used if more than one selected record period was considered for a station, or the selected record period with the closest departure to zero was used if the record periods were equal. For example, South Branch Potomac River at Franklin (01605500) is located in the Eastern Panhandle with record periods 1942–69 and 1978–2002. The feasible record periods for 1942–69 can be found in table 10 by locating the table entry where the first year is 1942 and the years of record are 28; the feasible records are in the field defined by every table entry to the left and increasing by one entry down with each entry to the left. There are 2 record periods with the maximum number of record years, 12 years beginning in 1943 with the table value of -0.040 and 12 years beginning in 1946 with the table value of -0.011. The feasible record period for 1942–69 is 1946–57 with the tabled value of -0.011 because the tabled average departure is nearest to zero. The feasible record periods for 1978–2002 can be found in table 10 by locating the table entry where the first year is 1978 and the years of record are 25; the feasible records are in the field defined by every table entry to the left and increasing by one entry down with each entry to the left. The feasible record period for 1978–2002 is the 12 years 1978–89 with the tabled value of 0.039 because this is the period with the maximum number of record years. Finally, the subset record period is 1946–57 with the tabled value of -0.011 because the feasible records determined for the station record periods 1942–69 and 1978–2002 both have record lengths of 12 years and the feasible record period is the tabled value nearest zero.

Table 1 lists stations where streamflow statistics are published in this report; 77 of the 110 stations with a minimum of 10 years of record in West Virginia have a period of record that was included in the subset of record periods. The stations are areally distributed across the State, including the northern panhandle and the area along the Ohio River. Table 11, near the end of this report, lists the selected statistics that are representative of 1930–2002, and these values supersede those published by Friel and others (1989).

Record periods for 40 stations near but outside West Virginia were selected from the subset of record periods for the appropriate region, and the streamflow statistics computed from these record periods (table 12, at the end of this report) are representative of 1930–2002. These statistics can be used to assist in determining flows for West Virginia, but they do not supersede the values determined for use by the particular state.

Criterion-based sampling of the available record periods was superior to record-extension techniques for this study because more stations were selected and areal distribution of stations was more widespread. Climate variability is likely the primary cause of the regional patterns in the standardized departures of minimum flows. Comparisons of minimum flows between stations considered for record extension could have different slopes for different time periods (Riggs, 1972). For example, one station could be in the Lower Appalachian Plateaus and the other station in the Upper Appalachian Plateaus with record periods 1963–69 and 1963–79, respectively. Stations in both regions have much less than average minimum flows for 1963–69, but the minimum flows for the Lower Appalachian Plateaus are much greater than those for the Upper Appalachian Plateaus for 1970–79 (figs. 9 and 10). These stations could be in the same basin, and the correlation between the stations could be 0.80 or greater, but the extension of the station in the Lower Appalachian Plateaus for the period 1970–79 would reflect the lower flow of the station in the Upper Appalachian Plateaus. Station statistics computed with this type of error from record-extension techniques can make it more difficult to determine significant independent variables when developing estimating equations for ungaged stations. Criterion-based sampling of the available record is not prone to this error. Also, the criterion-based sampling allows for computation of medium-flow statistics, such as 50-percent flow duration and EPA harmonic-mean flow, whereas record-extension techniques are limited to computation of only low-flow statistics; medium flows are also affected by climate variability (Lins and Slack, 1999; McCabe and Wolock, 2002).

The average minimum flows were computed for the entire record period and the subset record period for stations in West Virginia (table 13 at back of report) to quantify some of the effects resulting from criterion-based sampling. The entire record periods for 13 stations were included in the feasible record periods (figs. 12–14 and tables 8–10) making the entire record period equal to the subset record period. There were no subset record periods for 33 stations. The average minimum flows were divided by the respective drainage areas for the stations and plotted for the entire record period (fig. 15) and the subset record period (fig. 16) for comparison.

Two stations have much greater minimum flows than all other stations with respect to drainage area (identified as No. 1 in fig. 15): Tuscarora Creek above Martinsburg (01617000) and North Fork Cranberry River near Hillsboro (03187300). Tuscarora Creek is in a limestone area of karst topography, and its contributing drainage area probably is greater than the drainage area determined from topography. Tuscarora Creek would not be considered for developing estimating equations even if a subset record period had been determined because of insufficient information for streams in karst areas of the State. The record period for North Fork Cranberry River, 1970–82 (table 13), was a consistently wet period of high standardized departures without a subset record period.

Figures 15 and 16 identify stations within the Potomac River Basin as dark-shaded circles. Two stations are identified as outliers from this plot (No. 2 in fig. 15): Tuscarora Creek above Martinsburg (01617000) and Little Cacapon River near Levels (016098000). Tuscarora Creek is a high outlier as discussed above, and Little Cacapon River has lower minimum flows than the rest of the Potomic River Basin. The record period for Little Cacapon River, 1968–77 (table 13), incorporates the period when minimum flows increased suddenly around 1970. Neither of these stations has subset record periods.


Plot showing unit average minimum flows for the entire record period at 110 stations in West Virginia (Open circle indicates station outside the Potomac River Basin and 50 miles or greater from the Ohio River; solid square indicates station within the Potomac River basin; solid triangle indicates station within 50 miles of the Ohio River; generally, points below the dashed line represent stations within 50 miles of the Ohio River; the numbered stations correspond to numbered discussions in text).,

Figure 15. Unit average minimum flows for the entire record period at 110 stations in West Virginia (Open circle indicates station outside the Potomac River Basin and 50 miles or greater from the Ohio River; solid square indicates station within the Potomac River basin; solid triangle indicates station within 50 miles of the Ohio River; generally, points below the dashed line represent stations within 50 miles of the Ohio River; the numbered stations correspond to numbered discussions in text).,


Plot showing unit average minimum flows for the subset record period at 77 stations in West Virginia (Open circle indicates station outside the Potomac River Basin and 50 miles or greater from the Ohio River; solid square indicates station within the Potomac River Basin; solid triangle indicates station within 50 miles of the Ohio River; generally, points below dashed line represent stations within 50 miles of the Ohio River).

Figure 16. Unit average minimum flows for the subset record period at 77 stations in West Virginia (Open circle indicates station outside the Potomac River Basin and 50 miles or greater from the Ohio River; solid square indicates station within the Potomac River Basin; solid triangle indicates station within 50 miles of the Ohio River; generally, points below dashed line represent stations within 50 miles of the Ohio River).


East Fork Twelvepole Creek near Dunlow (03206600) is a minor stream flowing directly into the Ohio River with a record period of 1966–2002 (No. 3 in fig. 15). The record period was a consistently wet period of high standardized departures without a subset record period. East Fork Twelvepole Creek has a minimum flow higher than other streams within 50 mi of the Ohio River with respect to drainage area (note dashed line in figs. 15 and 16).

Guyandotte River near Bailysville (03202400) and Tug Fork at Welch (03212750) had different record periods between 1970 and 2002 during a consistently wet period of high standardized departures (No. 4 in fig. 15). The minimum flows were in the high range compared with other stations and there are no subset record periods for either station.

New River at Bluestone Dam (0318000), New River at Hinton (031845000), New River at Caperton (03185500), and Kanawha River at Kanawha Falls (03193000) are the stations with the greatest drainage areas, and their record periods ended in 1948 because of regulation (No. 5 in fig. 15). These stations had record periods during a consistently dry period of low standardized departures without subset record periods.

Cobun Creek at Morgantown (03062400), Camp Creek near Camp Creek (03178500), Leading Creek near Glenville (03152500), Bluestone River at Lilly (03179500), and Tygart Valley River at Fetterman (03056500) are all stations near the line below which minor streams flowing directly to the Ohio River plotted (No. 6 in fig. 15). Record periods for these stations spanned either the sudden increase in minimum flows around 1970 or a consistently dry period of low standardized departures, and there are no subset record periods.

The plot of subset record periods (fig. 16) identifies two subpopulations— stations within 50 mi of the Ohio River and stations in the remainder of the State—that are not easily discerned from the plot of the entire record periods (fig. 15). The purpose sampling of the entire record periods eliminates outliers that are not included in the subpopulation of records that represent 1930–2002.

Summary

The U.S. Geological Survey, in cooperation with the West Virginia Department of Environmental Protection, Division of Water and Waste Management, evaluated the low-flow patterns and statistics at U.S. Geological Survey streamflow-gaging stations in or near West Virginia. The effects of climate variability were probably the principal causes of the low-flow patterns observed at stations across the State.

Five time periods were identified between 1930 and 2002 with similar low-flow patterns, and average minimum flows for 15 stations were computed for the 5 time periods and the period 1930–2002. Average minimum flows for 1930–42, 1943–62, and 1963–69 were less than the average minimum flows for 1930–2002, and average minimum flows for 1970–79 and 1980–2002 were greater than the average minimum flows for 1930–2002. An abrupt change from a period of less-than-average to greater-than-average minimum flows was noted around 1970. The period of lowest minimum flows was 1963–69, and the period of greatest minimum flows was 1970–79; however, there was probably a period before 1930 with minimum flows greater than during 1970–79.

Variability of selected low-flow statistics for the 5 time periods identified between 1930 and 2002 at 15 stations, was analyzed both annually and seasonally. The selected low-flow statistics were the 1Q10, 7Q10, 7Q30, 1B3, 4B3, and the EPA harmonic-mean flow. Annually, the magnitude of the variability decreases with increasing magnitudes of the flow statistic. The values for 1Q10, 7Q10, 1B3, and 4B3 range from -93.9 to 582.5 percent for the individual stations for each selected time period from the values computed for 1930–2002, and the values for 30Q5 and the EPA harmonic-mean flow range from -62.3 to 281.2 percent. The maximum variation for an individual station is 582.5 percent greater for 7Q10 for the period 1970–79. A consistent trend was noted in the variability between the hydrologically based flows 1Q10 and 7Q10 and the biologically based flows 1B3 and 4B3. Hydrologically based flows indicate approximately equal or smaller absolute differences than biologically based flows for all selected time periods. Seasonally, there is no consistent trend between lower and higher low flows, and the average differences for 15 stations for 1970–79 in the summer (July 1–September 30) and fall (October 1–December 31) are the greatest average differences for any of the periods investigated. The selected statistics range from -95.7 to 683.6 percent for the individual stations for the selected time periods.

Comparisons between the 1Q10 and 1B3 and the 7Q10 and 4B3 were made for 15 stations. Annually, the 1B3 and 4B3 average less than the 1Q10 and 7Q10, respectively, and range from 28.5 percent less to 13.6 percent greater. Seasonally, the biologically based flow was less than the hydrologically based flow in the winter (January 1–March 31) and fall, greater in the spring (April 1–June 30), and varied among the individual stations during the summer.

Station records are available predominantly after about 1970, when minimum flows are greater than the 1930–2002 average. Some short-term station records are mostly during dry periods, whereas others are mostly during wet periods.

Record extension of stations as a means of deriving data representative of 1930–2002 was not feasible because no stations in the northern panhandle and only 4 stations within 50 mi of the Ohio River could be extended to 1930–2002. The areal distribution of stations was insufficient for developing estimating equations for ungaged stream locations. Instead, a criterion-based sampling of the entire record periods at stations was taken to reduce the effects of the entire record periods not representing those between 1930 and 2002. The sampling criterion reduced the inherent bias of entire record periods towards the higher-than-average minimum flows after about 1970 and was based on a comparison between regional minimum flows and station minimum flows. The regional minimum flows were determined from an analysis of 15 stations in West Virginia and 5 stations from surrounding states.

Principal component and correlation analyses on the 20 stations reduced the number of stations to 17 and identified three regions of the State: the Lower Appalachian Plateaus, the Upper Appalachian Plateaus, and the Eastern Panhandle. Generally, the Lower Appalachian Plateaus had less annual precipitation (about 40 to 50 in.) compared to the Upper Appalachian Plateaus (about 50 to 60 in.). The Greenbrier River Basin was included in the Upper Appalachian Plateaus with an annual precipitation of about 42–48 in. because of rain-shadow effects.

The difference in standardized departures of the minimum flows between the Lower and Upper Appalachian Plateaus regions may be a result of increased storm-cloud densities in the summer and fall after about 1970. Precipitation that typically did not fall until reaching the central mountainous area of the State (where mean annual precipitation is the greatest) could have started falling sooner, resulting in greater relative increases in low flows in the Lower Appalachian Plateaus and lesser or no relative increases in low flows in the Upper Appalachian Plateaus.

Record periods of 10 years or greater between 1930 and 2002 were determined for stations in or near West Virginia on the basis of sampling criterion. The samples of station records are representative of the population for 1930–2002. The record periods for 77 stations in West Virginia and 40 stations near West Virginia, and selected statistics for these record periods are presented. These statistics can be used to develop equations to estimate flow at ungaged stream locations.

Acknowledgments

The author thanks William H. Kirby for assistance in developing technical discussions, particularly those for criterion-based sampling. Thanks also to William P. Bartlett for help adding clarity to the report with additional discussions and revisions to presentations.

References Cited

Borchers, J.W., Ehlke, T.A., Mathes, M.V. Jr., and Downs, S.C., 1991, The effects of coal mining on the hydrologic environment of selected stream basins in southern West Virginia: U.S. Geological Survey Water-Resources Investigations Report 84–4300, 119 p.

Friel, E.A., Embree, W.N., Jack, A.R., and Atkins, J.T. Jr., 1989, Low-flow characteristics of streams in West Virginia: U.S. Geological Survey Water-Resources Investigations Report 88–4072, 34 p.

Goetz, J. P., and LeCompte, M. D., 1984, Ethnography and qualitative design in educational research: Academic Press, Orlando, Fla., 292 p.

Helsel, D.R., and Hirsch, R.M., 2002, Statistical methods in water resources: U.S. Geological Survey Techniques of Water-Resources Investigations, book 4, chap. A3, 510 p.

Hirsch, R. M., Slack, J.R., and Smith, R.A., 1982, Techniques of trend analysis for monthly water quality data: Water Resources Research, v. 18, no. 1, p. 107–121.

Hobba, W.A., Jr., 1981, Effects of underground mining and mine collapse on the hydrology of selected basins in West Virginia: West Virginia Geologic and Economic Survey Report of Investigations RI–33, 77 p.

Karl, T.R., and Knight, W.R., 1998, Secular trends of precipitation amount, frequency, and intensity in the USA: Bulletin of the American Meteorological Society, v. 79, p. 231–241.

Kendall, M.G., 1975, Rank correlation methods (4th ed.): London, Charles Griffin, 202 p.

Lane, E.W., and Lei, Kai, 1950, Stream flow variability: American Society of Civil Engineers, Transactions, v. 115, p. 1084–1134.

Lins, H.F., and Slack, J.R., 1999, Streamflow trends in the United States: Geophysical Research Letters, v. 26, p. 227–230.

Mann, H.B., 1945, Non-parametric test against trend: Econometrica, v. 13, p. 245–259.

MathSoft, 1999, S-PLUS 2000 guide to statistics: Seattle, Washington, volumes I, II, and III [variously paged].

McCabe, G.J., and Wolock, D.M., 2002, A step increase in streamflow in the conterminous United States: Geophysical Research Letters, v. 29, no. 24, 2185, doi:1029/200GL015999.

Puente, C., and Atkins, J.T., 1989, Simulation of rainfall-runoff response in mined and unmined watersheds in coal areas of West Virginia: U.S. Geological Survey Water-Supply Paper 2298, 48 p.

Riggs, H.C., 1972, Low-flow investigations: U.S. Geological Survey Techniques of Water-Resources Investigations, book 4, chap. B1, 18 p.

Rossman, L.A., 1990, DFLOW user's manual: U.S. Environmental Protection Agency, 26 p.

Runner, G.S., Bragg, R.L., and Atkins, J.T., Jr., 1989, Cost effectiveness of the stream-gaging program in West Virginia: U.S. Geological Survey Water-Resources Investigations Report 87–4089, 57 p.

Searcy, J.K., 1959, Flow-duration curves; manual of hydrology, part 2, Low-flow techniques: U.S. Geological Survey Water-Supply Paper 1542–A, 33 p.

U.S. Department of Agriculture, Natural Resources Conservation Service, 2004, West Virginia precipitation data/maps, accessed September 13, 2004, at URL http://www.ncgc.nrcs.usda.gov/branch/gdb/products/climate/data/precipitation-state/wv.html

U.S. Environmental Protection Agency, 1986, Technical guidance manual for performing wasteload allocations— Book VI, design conditions, chapter 1, stream design flow for steady-state modeling: Washington, D.C., U.S. Environmental Protection Agency, Office of Water, EPA 440/4–86–014 [variously paged].

Wiley, J.B., Evaldi, R.D., Eychaner, J.H., and Chambers, D.B., 2001, Reconnaissance of stream geomorphology, low streamflow, and stream temperature in the mountaintop coal-mining region, southern West Virginia, 1999–2000: U.S. Geological Survey Water-Resources Investigations Report 01–4092, 34 p.

Table 5. Differences between selected seasonal statistics computed for 1930–2002 and the statistics computed for the indicated record periods for 15 stations in West Virginia.

[Winter, January 1–March 31; spring, April 1–June 30; summer, July 1–September 30; fall, October 1–December 31; station numbers for the 15 stations are 01606500, 01608500, 01611500, 01636500, 03051000, 03053500, 03061500, 03066000, 03069500, 03070500, 03182500, 03183500, 03186500, 03198500, and combined stations 03214000 and 03214500; a negative value means the average for the indicated record period is less than the average for 1930–2002; a positive value means the average for the indicated record period is greater than the average for 1930–2002]

Station number Difference for the indicated period, in percent
1930–42 1943–62 1963–69 1970–79 1980–2002
1-day 10-year hydrologically based low flow (1Q10) for winter
01606500 -8.5 -2.2 -16.8 60.2 -3.7
01608500 1.5 -6.7 -25.3 58.5 -2.3
01611500 -8.6 -8.6 -16.7 95.5 1.5
01636500 -22.4 3.6 -23.6 78.0 3.4
03051000 12.3 15.1 -17.5 50.6 -20.3
03053500 -6.7 24.0 -17.7 36.7 -14.1
03061500 -20.2 -0.4 -39.8 83.6 27.6
03066000 -7.5 14.0 1.2 20.9 -13.0
03069500 -13.4 18.9 3.9 29.6 -13.0
03070500 -13.2 -6.3 14.1 40.4 -0.2
03182500 5.8 2.4 18.2 55.3 -21.1
03183500 -6.0 12.0 -9.5 50.0 -16.9
03186500 -10.5 25.5 30.0 45.1 -20.9
03198500 -38.7 -1.9 -37.7 156.1 20.2
a 03214000 and 03214500 No value b 0.1 b -35.5 b 181.1 c 33.5
1-day 10-year hydrologically based low flow (1Q10) for spring
01606500 4.0 28.6 -26.8 -6.5 -1.2
01608500 -0.8 32.6 -28.7 -0.1 -2.8
01611500 1.8 15.3 -22.8 -7.9 6.8
01636500 -13.7 19.0 -15.5 8.9 1.6
03051000 -1.2 52.4 -44.6 9.6 -6.3
03053500 -14.5 74.2 -43.0 -10.8 -0.1
03061500 -67.3 9.8 -1.6 135.3 36.7
03066000 -3.3 18.7 -32.1 7.2 -4.1
03069500 -3.5 46.9 -34.8 9.7 -9.3
03070500 8.5 1.8 -51.4 101.0 4.3
03182500 -0.2 55.5 -35.5 16.3 -9.5
03183500 -0.9 59.4 -37.6 22.5 -12.3
03186500 -21.2 80.1 -45.4 70.4 -10.5
03198500 -63.3 39.1 -31.6 66.0 86.9
a 03214000 and 03214500 No value b 1.9 b 8.7 b 63.8 c 57.7
1-day 10-year hydrologically based low flow (1Q10) for summer
01606500 -3.6 6.1 -18.3 28.0 5.0
01608500 -2.5 6.6 -29.7 61.5 11.7
01611500 -1.6 8.3 -33.0 22.2 17.8
01636500 -17.8 14.5 -23.4 22.4 10.6
03051000 -62.2 19.7 58.5 557.4 13.4
03053500 -52.6 3.7 15.9 288.4 15.7
03061500 -66.5 -23.6 23.2 301.0 141.6
03066000 3.2 -27.3 -1.4 84.9 10.8
03069500 -28.9 -12.0 -16.3 159.3 21.0
03070500 1.5 -43.6 6.3 146.2 60.9
03182500 -38.8 8.4 -31.7 109.7 31.8
03183500 -17.1 2.3 0.2 64.5 -0.1
03186500 -11.3 -15.7 9.8 267.5 -13.2
03198500 -49.1 -33.9 -30.6 396.9 218.9
a 03214000 and 03214500 No value b -10.8 b 16.2 b 121.5 c 126.6
1-day 10-year hydrologically based low flow (1Q10) for fall
01606500 -7.9 0.0 -17.9 25.8 6.0
01608500 -14.6 1.2 -25.7 47.6 12.3
01611500 -13.4 0.4 -16.4 12.8 9.3
01636500 -26.0 6.6 -5.7 31.6 12.4
03051000 -48.2 -12.8 -2.5 385.1 23.9
03053500 -68.2 -34.4 -2.8 493.3 124.4
03061500 -52.0 -28.9 21.8 437.3 146.1
03066000 -9.4 -40.0 39.7 164.6 41.8
03069500 -22.7 -33.0 5.6 153.6 40.6
03070500 -16.5 -54.8 33.6 241.6 99.6
03182500 -21.5 -2.0 -33.7 56.5 23.5
03183500 -14.0 -9.3 -6.0 43.7 10.0
03186500 -9.6 -45.3 43.2 158.0 36.9
03198500 -43.3 -31.6 35.6 168.3 210.6
a 03214000 and 03214500 No value b 1.1 b 25.3 b 88.9 c 135.2
7-day 10-year hydrologically based low flow (7Q10) for winter
01606500 2.0 -8.1 -16.1 63.7 -4.9
01608500 9.1 -11.2 -26.0 69.5 -1.1
01611500 -10.0 -9.0 -22.8 113.8 4.0
01636500 -17.8 2.6 -19.8 73.7 -0.8
03051000 11.3 13.9 -25.2 41.1 -17.1
03053500 -1.4 17.9 -25.8 26.8 -11.4
03061500 -25.3 -3.2 -38.8 58.1 30.3
03066000 16.5 3.0 -17.2 4.1 -6.7
03069500 -1.5 12.4 -11.1 12.8 -10.3
03070500 5.9 -10.1 -3.6 18.0 -0.2
03182500 11.1 -1.4 5.9 39.4 -17.6
03183500 -9.2 7.4 -6.8 23.6 -12.6
03186500 -79.9 -52.5 11.5 26.9 -10.0
03198500 -81.1 -28.8 -34.7 143.4 26.3
a 03214000 and 03214500 No value b 1.4 b -29.8 b 162.3 c 33.0
7-day 10-year hydrologically based low flow (7Q10) for spring
01606500 3.3 42.5 -25.1 -8.4 -6.5
01608500 -0.4 39.8 -26.9 -5.7 -6.0
01611500 3.2 17.9 -24.9 -9.0 3.9
01636500 3.6 23.2 -21.0 -3.9 -4.0
03051000 -5.7 58.8 -40.9 16.3 -15.2
03053500 -17.7 86.7 -47.3 -10.4 -3.2
03061500 -61.0 2.5 -2.1 128.2 29.8
03066000 -6.1 22.5 -34.1 15.1 -5.6
03069500 -3.7 53.9 -34.6 6.8 -13.1
03070500 6.5 -2.4 -54.4 108.4 5.3
03182500 6.2 60.4 -27.3 10.2 -16.4
03183500 -1.0 53.1 -28.8 11.2 -14.4
03186500 -84.5 -86.9 -44.6 52.0 -14.8
03198500 -89.3 -86.9 -29.2 45.1 68.8
a 03214000 and 03214500 No value b 8.1 b 3.6 b 49.9 c 42.4
7-day 10-year hydrologically based low flow (7Q10) for summer
01606500 -3.0 5.3 -19.6 30.7 6.6
01608500 -5.4 6.9 -27.7 59.5 12.5
01611500 -1.2 5.8 -31.3 22.7 17.2
01636500 1.3 12.1 -28.4 12.1 3.9
03051000 -61.9 -0.9 40.3 649.3 30.7
03053500 -53.7 0.1 30.4 298.1 16.9
03061500 -60.1 -16.7 22.1 230.8 98.7
03066000 5.4 -22.0 -16.9 84.0 8.8
03069500 -24.8 -17.1 -14.5 175.3 23.8
03070500 -4.9 -39.4 2.0 129.2 59.9
03182500 -30.4 2.1 -30.0 116.6 20.7
03183500 -17.7 1.9 -2.5 60.5 2.0
03186500 -3.5 -18.1 2.3 279.2 -12.7
03198500 -46.0 -34.1 -29.8 380.0 182.7
a 03214000 and 03214500 No value b -9.8 b 12.9 b 115.8 c 115.9
7-day 10-year hydrologically based low flow (7Q10) for fall
01606500 -6.1 0.9 -17.1 18.3 6.5
01608500 -13.0 3.5 -25.9 37.2 11.0
01611500 -11.2 3.2 -17.1 14.9 12.4
01636500 -12.1 8.2 -14.4 16.2 4.0
03051000 -51.4 -22.9 34.0 270.4 24.6
03053500 -70.5 -33.4 2.4 428.6 114.1
03061500 -48.0 -30.7 39.7 369.1 94.9
03066000 -5.1 -39.8 35.5 138.5 32.7
03069500 -25.1 -34.6 23.7 121.4 37.4
03070500 -20.8 -58.7 15.2 260.6 112.1
03182500 -25.7 -6.2 -23.0 37.6 24.0
03183500 -18.0 -11.3 0.4 33.4 14.5
03186500 -13.6 -50.0 66.7 146.3 45.5
03198500 -38.0 -33.1 15.1 128.0 172.7
a 03214000 and 03214500 No value b -0.8 b 23.8 b 85.8 c 123.5
30-day 5-year hydrologically based low flow (30Q5) for winter
01606500 -9.6 3.9 -30.2 57.8 -2.1
01608500 -10.8 1.2 -29.6 61.4 -0.4
01611500 -18.2 3.5 -23.3 111.6 -8.4
01636500 -18.0 -3.0 -4.4 57.2 -2.0
03051000 -9.1 16.1 -35.6 5.1 8.0
03053500 -12.3 25.9 -39.8 -0.7 8.7
03061500 -14.9 30.1 -65.4 13.1 25.4
03066000 -5.7 6.2 -28.2 4.2 13.9
03069500 -8.0 10.9 -35.4 7.1 12.2
03070500 8.8 5.3 -24.4 0.2 5.4
03182500 -1.2 5.9 -25.2 18.8 0.5
03183500 -17.3 13.3 -24.8 13.4 7.7
03186500 -33.0 49.3 63.4 175.7 152.9
03198500 -46.1 10.8 52.9 294.6 208.6
a 03214000 and 03214500 No value b 13.1 b -28.2 b 66.6 c 10.7
30-day 5-year hydrologically based low flow (30Q5) for spring
01606500 -7.9 38.8 -28.9 -17.5 -1.1
01608500 -7.5 35.8 -32.0 -17.0 2.3
01611500 -7.7 26.2 -17.7 -4.2 -0.8
01636500 -2.7 21.0 -26.7 -8.0 4.4
03051000 3.0 23.2 -36.0 12.9 -10.5
03053500 -16.0 45.7 -46.5 9.8 -3.6
03061500 -20.9 5.0 -44.1 51.5 10.8
03066000 -14.1 26.2 -38.2 6.8 1.2
03069500 -5.8 47.9 -40.3 -4.0 -8.8
03070500 -4.3 5.9 -48.1 38.9 9.4
03182500 -6.3 57.2 -39.3 -11.9 -9.5
03183500 -11.7 37.6 -30.0 -8.6 -2.5
03186500 12.5 -14.6 231.2 486.7 520.4
03198500 -10.3 -39.2 188.5 355.0 603.4
a 03214000 and 03214500 No value b -2.6 b -10.1 b 22.9 c 43.0
30-day 5-year hydrologically based low flow (30Q5) for summer
01606500 -1.2 8.7 -24.3 29.8 3.3
01608500 -2.6 6.6 -30.4 43.3 5.3
01611500 -1.9 -0.3 -33.4 31.0 10.2
01636500 3.9 4.4 -28.3 17.1 3.7
03051000 -39.8 -9.0 -30.9 193.9 15.7
03053500 -42.6 -3.7 -25.7 128.7 25.4
03061500 -54.8 -10.0 -29.9 148.0 46.0
03066000 -1.8 -13.8 -29.5 69.5 7.2
03069500 -19.5 -8.1 -29.1 86.2 12.6
03070500 -3.4 -31.9 -38.2 81.5 56.9
03182500 -4.8 16.6 -45.9 60.2 1.6
03183500 -9.4 17.8 -23.7 46.0 -2.7
03186500 12.5 -14.6 -32.6 129.3 -4.6
03198500 -10.3 -39.2 -32.0 137.8 62.4
a 03214000 and 03214500 No value b -17.6 b -4.2 b 78.2 c 56.8
30-day 5-year hydrologically based low flow (30Q5) for fall
01606500 -12.4 -3.6 -20.0 38.4 3.9
01608500 -12.7 -2.7 -22.7 44.7 2.8
01611500 -12.4 -4.4 -16.7 49.9 -8.5
01636500 -9.6 9.5 -22.6 23.8 0.3
03051000 -37.2 -25.9 -17.9 152.0 21.9
03053500 -43.3 -39.3 -32.3 192.6 34.4
03061500 -45.0 -10.5 -40.0 210.9 37.8
03066000 0.8 -40.7 7.0 101.1 19.3
03069500 -16.5 -33.4 -2.7 96.6 21.7
03070500 -25.7 -30.7 -52.8 132.4 40.5
03182500 -36.8 -5.7 -15.6 73.6 14.2
03183500 -27.7 -9.8 -0.8 68.7 5.7
03186500 -31.0 -35.5 7.3 170.9 21.9
03198500 -49.3 -25.0 -12.7 104.4 67.9
a 03214000 and 03214500 No value b -5.1 b -5.6 b 109.0 c 60.4
1-day 3-year biologically based low flow (1B3) for winter
01606500 7.6 -4.8 -2.5 68.7 3.4
01608500 20.0 -6.4 -8.6 60.7 -0.7
01611500 16.4 -8.3 -9.8 100.3 3.2
01636500 -16.8 13.6 -17.1 75.1 -2.0
03051000 -22.3 14.4 -22.2 94.4 -7.0
03053500 0.0 21.0 -12.6 62.7 -0.1
03061500 -15.6 -33.6 -8.6 22.4 42.9
03066000 4.4 0.4 20.1 40.2 -15.7
03069500 -21.7 -0.4 -0.4 30.0 -19.6
03070500 -13.8 -29.9 30.1 31.9 24.0
03182500 3.5 -15.0 34.1 58.5 -24.6
03183500 -14.3 8.6 42.1 56.4 -12.9
03186500 -41.8 16.8 51.4 77.1 -13.8
03198500 -65.6 -19.8 -48.7 243.8 40.1
a 03214000 and 03214500 No value b -20.2 b -21.6 b 84.0 c 69.3
1-day 3-year biologically based low flow (1B3) for spring
01606500 -22.2 37.5 -2.1 -14.6 35.4
01608500 -32.1 27.8 -3.6 -27.0 40.9
01611500 -19.7 14.6 12.5 -36.2 15.6
01636500 -14.6 13.6 15.8 -2.2 -3.7
03051000 -34.7 13.3 -24.9 0.0 51.6
03053500 -6.6 21.1 0.0 -44.6 79.6
03061500 -56.2 -5.3 48.2 127.1 127.1
03066000 -14.8 4.3 -4.8 4.8 51.9
03069500 -35.3 9.6 0.0 -20.9 26.2
03070500 -21.1 -3.6 -14.0 14.7 90.0
03182500 -43.5 26.2 -14.0 -10.8 29.5
03183500 -18.9 17.2 1.6 -16.8 26.2
03186500 -34.2 36.8 -5.3 21.1 57.4
03198500 -68.8 8.7 0.0 26.7 104.2
a 03214000 and 03214500 No value b 14.4 b 55.5 b 49.3 c 137.0
1-day 3-year biologically based low flow (1B3) for summer
01606500 -6.0 4.0 -12.2 31.8 -0.2
01608500 -12.2 6.4 -15.4 77.1 27.0
01611500 -2.9 15.5 -26.3 15.8 21.1
01636500 -18.4 18.7 -34.4 11.8 19.9
03051000 -95.7 10.5 17.8 330.5 -9.1
03053500 -87.9 -3.5 54.0 211.1 10.4
03061500 -62.7 -13.4 47.8 407.5 179.1
03066000 -9.3 -14.4 0.0 64.3 0.0
03069500 -51.8 -19.1 -25.6 126.2 19.7
03070500 -3.0 -63.0 -26.5 85.8 17.7
03182500 -38.9 17.6 0.8 134.5 42.9
03183500 -40.3 -6.2 2.3 55.4 -1.9
03186500 0.5 -14.6 39.2 331.2 8.5
03198500 -61.7 -28.9 -29.2 543.5 306.7
a 03214000 and 03214500 No value b 9.8 b 19.7 b 127.1 c 120.6
1-day 3-year biologically based low flow (1B3) for fall
01606500 -17.9 3.8 -21.5 21.6 9.1
01608500 -13.3 9.5 -15.8 68.7 25.4
01611500 -12.2 2.0 -14.6 19.0 19.0
01636500 -32.0 7.9 -10.6 11.1 6.0
03051000 -84.0 -8.5 27.7 469.8 -45.5
03053500 -93.3 -3.4 20.9 683.6 30.2
03061500 -35.1 -23.4 55.8 416.9 193.5
03066000 -14.3 -31.7 -1.1 217.5 105.0
03069500 -69.4 -44.4 13.6 158.1 21.9
03070500 -49.3 -46.4 61.2 123.9 54.3
03182500 -41.4 -7.6 -22.8 135.3 101.7
03183500 -41.5 -16.7 2.3 67.0 24.6
03186500 16.8 -47.3 -0.9 244.5 40.0
03198500 -13.4 -34.6 -32.9 347.1 276.5
a 03214000 and 03214500 No value b 14.2 b 55.4 b 131.1 c 221.5
4-day 3-year biologically based low flow (4B3) for winter
01606500 19.1 -4.6 -3.9 57.2 -0.2
01608500 43.3 -5.7 -17.8 54.1 0.0
01611500 5.9 -14.3 -21.5 120.3 3.3
01636500 -14.0 11.3 -26.4 74.3 -3.6
03051000 -20.8 2.7 -36.2 66.7 -1.8
03053500 -1.4 12.7 -24.0 48.2 -4.3
03061500 17.3 -8.2 -10.4 74.5 83.6
03066000 10.8 11.7 -8.4 10.8 -13.2
03069500 -6.8 0.0 -12.5 16.6 -0.8
03070500 -9.1 -24.3 10.1 8.8 4.0
03182500 -5.7 -16.3 20.4 32.4 -27.2
03183500 -33.0 -0.5 13.0 46.5 -10.3
03186500 -46.4 19.5 24.8 44.8 -13.8
03198500 -72.5 -26.3 -62.7 154.2 21.3
a 03214000 and 03214500 No value b -22.9 b -43.1 b 76.3 c 39.5
4-day 3-year biologically based low flow (4B3) for spring
01606500 -17.6 40.0 -9.4 -23.5 31.8
01608500 -22.9 26.3 -9.6 -29.0 31.7
01611500 -18.3 22.2 16.7 -32.5 27.8
01636500 -8.5 13.3 7.2 -7.1 -3.4
03051000 -23.6 10.9 -10.1 -1.5 33.1
03053500 -15.1 23.8 -14.1 -43.0 73.5
03061500 -61.2 -18.6 37.0 99.4 102.2
03066000 -14.6 15.8 -10.7 -1.2 49.0
03069500 -15.9 19.9 -4.0 -19.9 23.9
03070500 -26.6 -5.3 -11.9 13.3 69.5
03182500 -18.9 26.6 -12.8 -15.5 37.6
03183500 -13.4 26.5 -1.1 -8.6 46.3
03186500 -26.8 49.8 18.8 -4.2 66.3
03198500 -56.7 9.9 3.3 17.4 95.6
a 03214000 and 03214500 No value b 17.8 b 45.6 b 64.5 c 120.7
4-day 3-year biologically based low flow (4B3) for summer
01606500 -5.7 7.2 -12.7 33.7 4.2
01608500 -9.1 17.0 -16.1 66.7 27.3
01611500 -2.8 16.5 -24.8 34.7 22.8
01636500 -12.4 19.6 -34.3 7.7 16.9
03051000 -88.3 -4.3 6.0 347.3 -1.6
03053500 -87.1 -7.4 10.8 289.8 -0.4
03061500 -57.4 -36.1 11.1 300.0 87.0
03066000 -7.8 -9.4 11.9 69.8 -3.4
03069500 -51.3 -14.8 -1.6 139.0 24.5
03070500 -1.9 -64.2 -10.1 100.8 26.3
03182500 -41.0 3.4 -15.4 118.8 28.9
03183500 -39.2 11.5 0.8 66.6 -1.6
03186500 -2.3 -22.3 16.2 300.0 8.3
03198500 -59.2 -5.1 -27.0 405.7 245.3
a 03214000 and 03214500 No value b 1.2 b 43.3 b 109.6 c 101.6
4-day 3-year biologically based low flow (4B3) for fall
01606500 -22.0 1.4 -20.3 16.9 6.9
01608500 -15.1 5.1 -21.5 52.0 15.2
01611500 -5.5 -1.1 -16.3 16.6 16.6
01636500 -20.9 5.0 -13.3 9.5 4.5
03051000 -84.8 -15.2 41.9 455.3 -43.1
03053500 -92.6 -22.3 -4.9 509.9 35.7
03061500 -40.2 -26.5 46.1 395.1 154.9
03066000 -28.4 -33.8 29.0 166.0 72.8
03069500 -65.0 -28.8 16.0 142.9 26.4
03070500 -42.1 -50.8 15.2 135.8 39.8
03182500 -49.9 -34.3 -37.6 68.5 41.6
03183500 -49.2 -21.8 0.9 41.5 11.2
03186500 -4.6 -43.9 5.4 223.2 42.1
03198500 -39.7 -46.0 13.4 206.0 200.0
a 03214000 and 03214500 No value b 8.2 b 55.1 b 114.3 c 186.6
U.S. Environmental Protection Agency harmonic-mean flow for winter
01606500 -0.2 -0.2 -18.2 40.4 -5.1
01608500 0.5 -1.9 -19.8 42.3 -3.9
01611500 -8.5 -1.1 -22.1 78.3 -3.6
01636500 -11.7 3.5 -16.4 48.5 -4.7
03051000 -1.5 9.6 -19.6 24.3 -7.3
03053500 -7.3 13.7 -20.1 15.6 -4.1
03061500 -2.6 5.9 -39.9 45.6 3.0
03066000 -6.7 6.0 -12.7 7.5 -0.7
03069500 -6.5 10.2 -17.3 11.1 -1.9
03070500 -0.7 -1.4 -12.9 16.4 0.4
03182500 7.9 1.0 -9.6 27.3 -9.6
03183500 -4.6 6.4 -12.5 28.4 -6.4
03186500 -4.1 8.1 -13.1 15.3 -5.9
03198500 -33.5 11.4 -33.5 82.4 12.9
a 03214000 and 03214500 No value b 11.7 b -25.3 b 85.6 c 8.9
U.S. Environmental Protection Agency harmonic-mean flow for spring
01606500 -16.6 8.1 -15.1 -7.4 16.0
01608500 -17.2 7.6 -15.4 -10.3 19.0
01611500 -17.9 7.5 -12.1 -3.1 14.0
01636500 -11.8 6.1 -18.4 1.3 9.6
03051000 -22.5 4.0 -19.4 1.2 25.1
03053500 -25.8 11.1 -24.7 -8.5 34.7
03061500 -46.6 -7.1 -13.9 42.6 48.7
03066000 -21.8 -1.6 -12.2 -2.4 27.6
03069500 -19.3 6.3 -14.9 -9.0 22.5
03070500 -25.4 -4.0 -17.9 16.1 30.8
03182500 -24.8 8.0 -13.1 -8.0 24.1
03183500 -25.0 6.4 -13.6 -6.4 28.0
03186500 -36.6 9.7 -11.4 4.6 31.4
03198500 -43.0 0.7 -15.0 14.3 53.8
a 03214000 and 03214500 No value b -2.6 b -5.9 b 32.4 c 43.7
U.S. Environmental Protection Agency harmonic-mean flow for summer
01606500 -4.0 3.3 -36.5 16.7 12.0
01608500 -7.1 2.5 -41.1 27.4 17.0
01611500 -10.6 0.0 -33.1 32.0 11.7
01636500 0.4 2.7 -37.0 16.2 9.6
03051000 -64.6 49.2 5.0 263.6 71.8
03053500 -56.0 29.7 -8.9 139.2 42.4
03061500 -54.8 -3.4 -33.0 169.3 61.3
03066000 -8.2 -9.4 -27.7 49.6 13.3
03069500 -25.3 1.8 -30.2 59.6 17.3
03070500 5.4 -25.8 -45.4 120.8 41.2
03182500 -18.8 9.4 -42.6 55.9 13.4
03183500 -13.4 6.7 -35.7 50.4 5.8
03186500 -13.6 -12.3 -24.3 141.3 6.0
03198500 -35.9 -26.5 -28.2 98.1 93.4
a 03214000 and 03214500 No value b -12.5 b 0.0 b 53.7 c 61.1
U.S. Environmental Protection Agency harmonic-mean flow for fall
01606500 -6.6 -2.0 -18.5 33.8 1.3
01608500 -7.1 -2.9 -21.6 42.3 2.9
01611500 -9.4 -3.8 -17.0 42.5 3.8
01636500 -8.4 2.5 -22.7 31.0 1.8
03051000 -50.3 -5.6 26.7 284.8 31.2
03053500 -66.9 -2.3 90.4 589.3 177.4
03061500 -46.4 -21.0 -24.0 196.6 61.5
03066000 -1.6 -28.8 -2.9 89.0 18.8
03069500 -23.8 -22.5 6.5 92.6 25.5
03070500 36.5 -56.0 20.8 273.6 143.3
03182500 -20.9 -4.0 -16.1 52.3 9.1
03183500 -15.0 -4.2 0.5 46.0 0.5
03186500 7.1 -35.4 16.8 163.7 14.6
03198500 -43.3 -22.9 -7.3 110.8 72.0
a 03214000 and 03214500 No value b -5.4 b 12.2 b 89.9 c 50.7

a 1930–2002 period estimated from record for 1936–85 at Tug Fork near Kermit (03214000).

b Computed from record for Tug Fork near Kermit (03214000).

c Estimated from record for 1986–2002 at Tug Fork at Kermit (03214500).

Table 8. Record periods for the Lower Appalachian Plateaus region for which the indicated average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930–2002 (six stations in West Virginia, Ohio, and Virginia).

[No value indicates the average departure was greater than 5 percent; light shading is for example presented in text; station numbers for the six stations are 03061500, 03070500, 03109500, 03198500, 03208500, and combined stations 03214000 and 03214500]

First year Years of record
10 11 12 13 14 15 16 17 18 19 20
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                      
1939                      
1940                      
1941                      
1942                      
1943                      
1944                      
1945                      
1946                      
1947                      
1948                      
1949                      
1950                      
1951                      
1952                      
1953                      
1954                      
1955                      
1956                   -0.034 0.012
1957                 0.008    
1958                   0.008 0.024
1959               0.008      
1960               0.000 0.018    
1961           -0.010          
1962         -0.007            
1963       -0.016              
1964     0.024                
1965 0.013                    
21 22 23 24 25 26 27 28 29 30 31
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                      
1939                      
1940                      
1941                      
1942                      
1943                      
1944                      
1945                      
1946                      
1947                      
1948                 -0.035 -0.023 0.015
1949               -0.029 -0.016 0.022  
1950             -0.031 -0.018 0.021    
1951           -0.021 -0.008 0.032      
1952           -0.032 0.011        
1953       -0.024 -0.010 0.033          
1954     -0.011 0.003              
1955 -0.010 0.033                  
1956                      
1957                      
1958                      
1959                      
1960                      
1961                      
1962                      
1963                      
1964                      
1965                      
32 33 34 35 36 37 38 39 40 41 42
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                      
1939                     -0.028
1940                   -0.014 0.013
1941               -0.039 0.010 0.037  
1942             -0.027 0.023      
1943         -0.037 -0.013 0.038        
1944         -0.032 0.021          
1945     -0.033 -0.009              
1946   -0.013 0.012                
1947 -0.007 0.019                  
1948                      
1949                      
1950                      
1951                      
1952                      
1953                      
1954                      
1955                      
1956                      
1957                      
1958                      
1959                      
1960                      
1961                      
1962                      
1963                      
1964                      
1965                      
43 44 45 46 47 48 49 50 51 52 53
1930                      
1931                      
1932                      
1933                      
1934                 -0.039 -0.021 -0.024
1935             -0.030 -0.028 -0.009 -0.013 -0.011
1936         -0.032 -0.017 -0.015 0.004 -0.001 0.002 -0.003
1937     -0.029 -0.020 -0.004 -0.003 0.016 0.011 0.013 0.008 -0.004
1938 -0.033 -0.007 0.001 0.017 0.018 0.037 0.031 0.033 0.027 0.014  
1939 -0.001 0.007 0.023 0.024   0.038 0.039 0.033 0.020    
1940 0.021 0.037 0.038         0.032      
1941                      
1942                      
1943                      
1944                      
1945                      
1946                      
1947                      
1948                      
1949                      
1950                      
1951                      
1952                      
1953                      
1954                      
1955                      
1956                      
1957                      
1958                      
1959                      
1960                      
54 55 56 57 58 59 60 61 62 63 64
1930                 -0.035   -0.027
1931               -0.030 -0.037 -0.022 -0.025
1932           -0.033 -0.011 -0.018 -0.003 -0.006 0.008
1933         -0.025 -0.003 -0.010 0.005 0.002 0.016 0.012
1934 -0.022 -0.026 -0.037 -0.006 0.016 0.008 0.024 0.020 0.034 0.029  
1935 -0.015 -0.027 0.004 0.027 0.019 0.035 0.030   0.039    
1936 -0.015 0.016 0.039 0.031              
1937 0.028                    
1938                      
1939                      
1940                      
1941                      
1942                      
1943                      
1944                      
1945                      
1946                      
1947                      
1948                      
1949                      
65 66 67 68 69 70 71 72 73    
1930 -0.030 -0.016 -0.019 0.009 0.010 0.009 0.002 0.014 0.015    
1931 -0.011 -0.014 0.014 0.015 0.015 0.007 0.019 0.020      
1932 0.003 0.033 0.033 0.032 0.024 0.036 0.037        
1933       0.032              
1934                      
1935                      
1936                      
1937                      
1938                      

Table 9. Record periods for the Upper Appalachian Plateaus region for which the indicated average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930–2002 (six stations in West Virginia).

[No value indicates the average departure was greater than 5 percent; station numbers for the six stations are 03051000, 03053500, 03066000, 03069500, 03182500, and 03186500]

First year Years of record
10 11 12 13 14 15 16 17 18 19 20
1930                      
1931                      
1932                     0.021
1933                   -0.024  
1934                 0.024 -0.016  
1935               -0.015      
1936             0.024 -0.020      
1937           -0.001 -0.046        
1938           -0.003         -0.024
1939         0.007         -0.018  
1940   -0.018   0.036 -0.028       0.002 -0.046 -0.032
1941 0.043     0.019   -0.017   0.040 -0.013 0.000  
1942     0.025   -0.015   0.046 -0.011 0.003   -0.041
1943     -0.025 0.023 -0.029   0.020 0.033 -0.024 -0.016 0.020
1944         -0.005   -0.046        
1945   -0.028     -0.021 -0.003     -0.012    
1946 0.037 -0.031   0.030 0.045 -0.025 -0.015 0.027 -0.016 -0.045  
1947     -0.013 0.007     -0.005        
1948       0.002 0.012   0.007 -0.027      
1949     0.040     0.037 -0.001        
1950 -0.002     -0.015              
1951                      
1952                      
1953                      
1954                      
1955                      
1956                      
1957                      
1958                      
1959                      
1960                      
1961                      
1962                      
1963                 0.029 0.032 0.019
1964                      
1965                      
1966       -0.042 -0.042            
1967 0.022 -0.022 0.028 0.023              
1968 0.033                    
1969                      
1970                      
1971                      
1972                      
1973                      
1974                      
1975                      
1976                      
1977                      
1978                      
1979                      
1980                      
1981             0.021        
1982           0.015          
1983         0.033            
1984       -0.017       0.025      
1985     0.038                
1986   0.004       0.046          
1987                      
1988       0.020              
1989                      
1990                      
1991   0.032 0.012                
1992 -0.036                    
1993 -0.015                    
21 22 23 24 25 26 27 28 29 30 31
1930                      
1931 -0.036                    
1932 -0.015         -0.029          
1933                      
1934       -0.030              
1935                      
1936   -0.035                  
1937                      
1938                      
1939                      
1940     -0.035                
1941 -0.041 -0.008 -0.040                
1942 -0.006 -0.039                  
1943 -0.017 -0.042                  
1944                      
1945                      
1946                      
1947                      
1948                      
1949                      
1950                     0.010
1951                   -0.003 0.000
1952                      
1953               -0.027 -0.023 -0.030 -0.007
1954             0.004 0.007 -0.001 0.022 -0.001
1955               0.038   0.036  
1956         0.024 0.027 0.017 0.041 0.016 0.030 0.013
1957           0.045   0.042   0.037  
1958     -0.014 -0.010 -0.019 0.008 -0.017 -0.002 -0.018 0.013 -0.018
1959   0.026 0.029 0.018 0.045 0.017 0.032 0.013 0.045 0.012 -0.016
1960 0.016 0.020 0.009 0.037 0.008 0.024 0.005 0.038 0.004 -0.024  
1961           0.044   0.040 0.009    
1962         0.040   0.037 0.005      
1963   0.017 0.035 0.013   0.012 -0.021        
1964     0.046   0.042 0.007          
1965         0.030            
1966                      
1967                      
1968                      
1969                      
1970                      
1971                      
1972                      
1973                      
1974                      
1975                      
1976                      
1977                      
1978                      
1979                      
1980                      
1981                      
1982                      
32 33 34 35 36 37 38 39 40 41 42
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                      
1939                     -0.016
1940                   -0.007 -0.005
1941                 0.008 0.011 0.005
1942               0.010 0.012 0.006 0.023
1943             0.024 0.026 0.019 0.036 0.018
1944           -0.011 -0.008 -0.014 0.004 -0.013 -0.003
1945         0.008 0.010 0.004 0.022 0.004 0.014 0.002
1946       0.028 0.030 0.023 0.040 0.022 0.031 0.019 0.040
1947     0.013 0.015 0.008 0.026 0.008 0.018 0.006 0.028 0.005
1948   0.042 0.043 0.035   0.034 0.044 0.030   0.028 0.007
1949             0.043   0.040 0.018  
1950 0.013 0.006 0.026 0.005 0.017 0.003 0.027 0.003 -0.019    
1951 -0.007 0.014 -0.007 0.006 -0.008 0.017 -0.008 -0.030      
1952 -0.029   -0.035   -0.021 -0.046   0.019 0.036 0.025 0.020
1953 -0.028 -0.014 -0.028 -0.001 -0.027   0.039   0.044 0.038 0.017
1954 0.012 -0.003 0.024 -0.003 -0.027         0.038 0.030
1955 0.031   0.029 0.004             0.036
1956 0.041 0.012 -0.014           0.044 0.023  
1957 0.034 0.007             0.041    
1958 -0.044         0.031 0.022 0.000   0.040 0.036
1959             0.024       0.037
1960         0.042 0.018       0.032  
1961                      
1962       0.044              
1963     0.025       0.039        
1964                      
1965                      
1966                      
1967                      
1968                      
1969                      
1970                      
1971                      
43 44 45 46 47 48 49 50 51 52 53
1930                      
1931               -0.045 -0.042 -0.046 -0.032
1932             -0.022 -0.020 -0.024 -0.010 -0.023
1933           -0.040 -0.038 -0.042 -0.027 -0.040 -0.031
1934         -0.023 -0.020 -0.024 -0.010 -0.023 -0.015 -0.024
1935       -0.038 -0.035 -0.039 -0.024 -0.038 -0.029 -0.037 -0.019
1936     -0.025 -0.022 -0.026 -0.012 -0.025 -0.016 -0.026 -0.007 -0.025
1937   -0.034 -0.031 -0.036 -0.020 -0.034 -0.025 -0.034 -0.015 -0.033  
1938 -0.019 -0.016 -0.021 -0.006 -0.020 -0.011 -0.021 -0.002 -0.020 -0.036 0.027
1939 -0.013 -0.018 -0.003 -0.017 -0.008 -0.018 0.001 -0.018 -0.034 0.030 0.043
1940 -0.010 0.006 -0.009 0.000 -0.010 0.009 -0.010 -0.027 0.038   0.042
1941 0.021 0.005 0.014 0.003 0.023 0.003 -0.015        
1942 0.006 0.016 0.004 0.024 0.004 -0.014         0.035
1943 0.028 0.016 0.036 0.015 -0.004         0.046 0.039
1944 -0.014 0.007 -0.014 -0.032 0.039   0.043 0.039 0.021 0.015 -0.001
1945 0.023 0.002 -0.017         0.035 0.029 0.012  
1946 0.018 -0.002           0.043 0.025    
1947 -0.015         0.040 0.033 0.015   0.046 0.043
1948             0.035       0.044
1949           0.045          
1950     0.040 0.033 0.014     0.044 0.025    
1951   0.032 0.024 0.005 0.045 0.039 0.036 0.018   0.044  
1952 0.000 -0.007 -0.026 0.015 0.010 0.008 -0.011 0.022 0.017    
1953 0.010 -0.010 0.032 0.026 0.023 0.004 0.037 0.032      
1954 0.010   0.046 0.042 0.023            
1955                      
1956     0.035                
1957                      
1958 0.015   0.045                
1959                      
1960                      
54 55 56 57 58 59 60 61 62 63 64
1930 -0.045       -0.039     -0.012 0.000 -0.007 -0.010
1931 -0.044 -0.036 -0.044 -0.027 -0.042   0.000 0.011 0.004 0.001 -0.012
1932 -0.015 -0.023 -0.006 -0.023 -0.037 0.019 0.031 0.024 0.020 0.006 0.002
1933 -0.040 -0.022 -0.038   0.005 0.017 0.010 0.007 -0.007 -0.012 -0.025
1934 -0.006 -0.023 -0.038 0.020 0.032 0.025 0.021 0.007 0.002 -0.012 0.018
1935 -0.036   0.009 0.021 0.013 0.010 -0.004 -0.009 -0.023 0.007 0.003
1936 -0.040 0.020 0.033 0.025 0.021 0.006 0.001 -0.013 0.018 0.014 0.012
1937 0.013 0.026 0.018 0.015 0.000 -0.006 -0.020 0.011 0.007 0.006 -0.008
1938 0.039 0.031 0.027 0.012 0.006 -0.008 0.023 0.019 0.017 0.003 0.028
1939 0.034 0.030 0.015 0.009 -0.006 0.026 0.022 0.020 0.005 0.030 0.027
1940 0.038 0.022 0.016 0.001 0.033 0.028 0.026 0.011 0.037 0.033  
1941 0.034 0.028 0.012 0.045 0.040 0.037 0.022   0.044    
1942 0.029 0.013   0.041 0.039 0.023   0.045      
1943 0.023       0.032            
1944 0.033 0.028 0.026 0.010 0.038 0.033          
1945 0.042 0.039 0.023   0.046            
1946   0.035                  
1947 0.026                    
1948                      
1949                      
65 66 67 68 69 70 71 72 73    
1930 -0.023 -0.027 -0.039 -0.011 -0.014 -0.016 -0.028 -0.005 -0.008    
1931 -0.016 -0.029 -0.001 -0.004 -0.006 -0.018 0.005 0.002      
1932 -0.012 0.017 0.013 0.011 -0.001 0.021 0.018        
1933 0.004 0.000 -0.001 -0.014 0.009 0.006          
1934 0.014 0.012 -0.001 0.022 0.019            
1935 0.002 -0.012 0.013 0.009              
1936 -0.002 0.022 0.019                
1937 0.017 0.013                  
1938 0.024                    

Table 10. Record periods for the Eastern Panhandle region for which the indicated average departure was within 5 percent of the standard deviation of the standardized departures of the minimum flows for 1930–2002 (five stations in West Virginia and Virginia).

[No value indicates the average departure was greater than 5 percent; station numbers for the five stations are 01606500, 01611500, 01632000, 01636500, and 01644000]

First year Years of record
10 11 12 13 14 15 16 17 18 19 20
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938         -0.034 -0.041 -0.033        
1939       -0.033 -0.041 -0.032          
1940   -0.024 -0.009 -0.019 -0.012            
1941 0.005 0.018 0.005 0.011 -0.030            
1942                      
1943 0.000 0.007 -0.040                
1944 -0.007                    
1945 0.001                    
1946 -0.004 -0.029 -0.011                
1947                      
1948 0.007                    
1949 -0.035                    
1950                      
1951                      
1952                      
1953                      
1954                      
1955                      
1956                      
1957                      
1958                      
1959                      
1960                      
1961                     0.037
1962                     0.042
1963                     0.023
1964       -0.032     -0.029        
1965     0.040 0.018 -0.014 0.029          
1966 -0.013                    
1967                      
1968                      
1969                      
1970                      
1971                      
1972                      
1973                      
1974                      
1975                      
1976                      
1977       0.017              
1978     0.039                
1979                      
1980 0.027                    
21 22 23 24 25 26 27 28 29 30 31
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                      
1939                      
1940                      
1941                      
1942                      
1943                      
1944                      
1945                      
1946                      
1947                      
1948                      
1949                      
1950                     -0.043
1951                      
1952                      
1953                      
1954                      
1955                      
1956                      
1957                      
1958                      
1959   -0.016 -0.019 -0.040 -0.033   -0.042        
1960 -0.005 -0.009 -0.031 -0.024 -0.043 -0.034 -0.042        
1961 0.032 0.007 0.013 -0.009 -0.001 -0.010 -0.019 -0.023 -0.035    
1962 0.015 0.021 -0.002 0.006 -0.004 -0.013 -0.018 -0.030      
1963 0.028 0.004 0.011 0.001 -0.009 -0.013 -0.027        
1964 0.029 0.036 0.025 0.014 0.008 -0.007          
1965         0.028            
1966                      
1967                      
1968                      
1969                      
1970                      
1971                      
1972                      
1973                      
1974                      
1975                      
1976                      
1977                      
1978                      
1979                      
1980                      
32 33 34 35 36 37 38 39 40 41 42
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                      
1939                      
1940                      
1941                      
1942                      
1943                      
1944                      
1945                      
1946       -0.043 -0.044            
1947                      
1948   -0.039 -0.040                
1949 -0.022 -0.024 -0.038 -0.033   -0.040         0.022
1950 -0.044                 0.007 0.014
1951                 -0.024 -0.016 -0.020
1952               -0.028 -0.020 -0.024 -0.013
1953             -0.025 -0.017 -0.021 -0.009 -0.013
1954           -0.028 -0.020 -0.023 -0.012 -0.016 0.004
1955         -0.013 -0.005 -0.009 0.002 -0.002 0.018 0.011
1956       0.005 0.013 0.008 0.020 0.015 0.035 0.027  
1957     0.013 0.021 0.016 0.028 0.022 0.042 0.034    
1958   0.008 0.016 0.011 0.023 0.018 0.039 0.031      
1959 0.039   0.041                
1960                      
1961                      
1962                      
1963                      
1964                      
1965                      
1966                      
1967                      
1968                      
1969                      
1970                      
1971                      
43 44 45 46 47 48 49 50 51 52 53
1930                      
1931                      
1932                      
1933                      
1934                      
1935                      
1936                      
1937                      
1938                     -0.030
1939                   -0.029 -0.023
1940                 -0.024 -0.018 -0.020
1941               -0.018 -0.012 -0.015 -0.006
1942             -0.033 -0.026 -0.029 -0.020 -0.023
1943           -0.020 -0.014 -0.017 -0.008 -0.011 0.005
1944         -0.024 -0.017 -0.020 -0.011 -0.014 0.002 -0.004
1945       -0.010 -0.004 -0.007 0.002 -0.002 0.014 0.009  
1946     0.003 0.009 0.005 0.015 0.011 0.027 0.021    
1947   -0.007 0.000 -0.004 0.006 0.002 0.018 0.012      
1948 0.008 0.014 0.010 0.020 0.016 0.032 0.026        
1949 0.028 0.024 0.033 0.028   0.038          
1950 0.010 0.020 0.015 0.033 0.026            
1951 -0.009 -0.013 0.006 0.000              
1952 -0.016 0.002 -0.004                
1953 0.006 -0.001                  
1954 -0.003                    
1955                      
1956                      
1957                      
1958                      
1959                      
1960                      
54 55 56 57 58 59 60 61 62 63 64
1930                      
1931                      
1932                      
1933                   -0.042  
1934         -0.043   -0.037 -0.039 -0.025 -0.029 0.032
1935       -0.042 -0.044 -0.036 -0.038 -0.024 -0.028 0.034 0.043
1936   -0.036 -0.030 -0.032 -0.024 -0.027 -0.013 -0.017      
1937 -0.038 -0.032 -0.035 -0.026 -0.029 -0.015 -0.019       0.042
1938 -0.024 -0.026 -0.018 -0.021 -0.006 -0.011          
1939 -0.026 -0.017 -0.020 -0.006 -0.010            
1940 -0.012 -0.015 0.000 -0.005              
1941 -0.009 0.006 0.001                
1942 -0.007 -0.012                  
1943 -0.001                    
1944                      
1945                      
1946                      
1947                      
1948                      
1949                      
65 66 67 68 69 70 71 72 73    
1930       -0.024 -0.014 -0.011 -0.023 -0.014 -0.016    
1931     -0.014 -0.005 -0.002 -0.015 -0.006 -0.007      
1932   0.003 0.012 0.016 0.002 0.011 0.009        
1933 0.016 0.025 0.028 0.014 0.023 0.021          
1934 0.041 0.044 0.030 0.039 0.036            
1935   0.032 0.041 0.038              
1936 0.043                    
1937                      
1938                      

Table 11. Selected annual and seasonal statistics for 77 stations in West Virginia representative of 1930–2002.

[Winter, January 1–March 31; spring, April 1–June 30; summer, July 1–September 30; fall, October 1–December 31; streamflow statistics are in cubic feet per second, except for variability index, which is dimensionless; the record period is in climatic years, April 1 through March 31of the indicated ending year; EPA, U.S. Environmental Protection Agency]

Streamflow statistic Annual Season
Winter Spring Summer Fall
01595300 Abram Creek at Oakmont, WV, 1959 –1982
1-day 2-year hydrologically based flow 2.20 26.0 9.92 2.30 4.82
1-day 5-year hydrologically based flow 0.77 12.6 4.86 0.78 2.06
1-day 10-year hydrologically based flow 0.41 7.61 3.24 0.41 1.35
3-day 2-year hydrologically based flow 2.37 25.0 11.1 2.52 5.22
3-day 5-year hydrologically based flow 0.83 14.7 5.48 0.85 2.29
3-day 10-year hydrologically based flow 0.44 11.0 3.66 0.45 1.51
7-day 2-year hydrologically based flow 2.72 28.2 13.6 2.96 6.04
7-day 5-year hydrologically based flow 0.95 16.1 6.73 0.98 2.64
7-day 10-year hydrologically based flow 0.50 11.8 4.51 0.51 1.75
14-day 2-year hydrologically based flow 3.25 32.3 18.1 3.70 7.14
14-day 5-year hydrologically based flow 1.18 18.2 9.32 1.26 3.14
14-day 10-year hydrologically based flow 0.64 13.3 6.48 0.66 2.08
30-day 2-year hydrologically based flow 4.56 46.1 29.2 5.73 12.2
30-day 5-year hydrologically based flow 1.97 27.0 14.9 2.29 5.12
30-day 10-year hydrologically based flow 1.23 20.3 10.3 1.34 3.22
1-day 3-year biologically based flow 0.17 4.99 7.50 0.29 0.19
4-day 3-year biologically based flow 0.37 5.89 10.4 0.44 0.94
EPA harmonic-mean flow 9.11 37.1 52.4 4.55 5.80
5-percent-duration flow 251 374 260 74.7 166
10-percent-duration flow 168 264 195 45.6 111
15-percent-duration flow 127 210 158 32.7 83.9
20-percent-duration flow 104 173 131 25.4 68.2
25-percent-duration flow 85.8 146 112 21.0 57.3
30-percent-duration flow 71.3 126 95.4 17.8 48.7
35-percent-duration flow 60.7 112 84.5 15.0 42.2
40-percent-duration flow 51.4 99.9 74.7 13.1 36.6
45-percent-duration flow 43.6 89.0 65.6 11.3 31.6
50-percent-duration flow 36.9 78.8 58.0 9.5 26.5
55-percent-duration flow 30.7 71.0 51.4 8.1 21.9
60-percent-duration flow 25.2 63.3 45.4 6.8 17.5
65-percent-duration flow 20.1 55.7 40.4 5.8 13.4
70-percent-duration flow 15.7 49.3 34.8 4.8 10.2
75-percent-duration flow 12.1 43.5 29.3 3.9 7.8
80-percent-duration flow 8.7 36.5 24.0 3.1 6.3
85-percent-duration flow 6.3 31.0 18.8 2.2 5.1
90-percent-duration flow 4.3 25.6 14.0 1.6 3.9
95-percent-duration flow 2.3 18.3 9.3 1.0 2.5
99-percent-duration flow 0.9 11.1 3.9 0.3 1.5
Variability index 0.62 0.39 0.44 0.56 0.57
01599500 New Creek near Keyser, WV, 1949 –1958
1-day 2-year hydrologically based flow 2.17 14.5 8.72 2.23 2.78
1-day 5-year hydrologically based flow 1.49 6.67 6.71 1.47 1.73
1-day 10-year hydrologically based flow 1.24 4.18 5.82 1.21 1.37
3-day 2-year hydrologically based flow 2.24 15.1 9.55 2.33 2.91
3-day 5-year hydrologically based flow 1.50 6.91 7.18 1.51 1.80
3-day 10-year hydrologically based flow 1.23 4.33 6.14 1.23 1.41
7-day 2-year hydrologically based flow 2.43 16.8 11.5 2.53 3.58
7-day 5-year hydrologically based flow 1.61 7.45 8.67 1.62 2.25
7-day 10-year hydrologically based flow 1.31 4.72 7.31 1.31 1.75
14-day 2-year hydrologically based flow 2.68 24.8 13.5 2.92 4.04
14-day 5-year hydrologically based flow 1.74 10.1 10.2 1.82 2.43
14-day 10-year hydrologically based flow 1.40 5.82 8.71 1.44 1.90
30-day 2-year hydrologically based flow 3.15 34.9 21.5 3.46 6.10
30-day 5-year hydrologically based flow 2.05 15.9 16.6 2.16 3.35
30-day 10-year hydrologically based flow 1.67 9.98 14.7 1.73 2.40
1-day 3-year biologically based flow 1.09 2.97 6.70 1.05 1.39
4-day 3-year biologically based flow 1.30 3.40 7.80 1.35 1.66
EPA harmonic-mean flow 8.40 22.1 34.3 5.03 4.95
5-percent-duration flow 168 245 192 37.9 90.2
10-percent-duration flow 115 170 122 18.1 51.5
15-percent-duration flow 87.0 146 98.0 13.7 37.7
20-percent-duration flow 69.8 127 82.2 10.9 28.0
25-percent-duration flow 57.6 111 69.9 9.2 21.8
30-percent-duration flow 47.4 98.6 60.6 8.2 16.4
35-percent-duration flow 37.8 88.2 53.8 7.3 13.4
40-percent-duration flow 30.3 80.4 47.8 6.7 11.4
45-percent-duration flow 24.4 72.6 42.3 6.1 9.5
50-percent-duration flow 19.3 64.9 37.5 5.5 8.2
55-percent-duration flow 15.0 58.4 33.7 5.0 7.3
60-percent-duration flow 11.8 52.4 30.0 4.4 6.4
65-percent-duration flow 9.2 47.0 26.3 3.9 5.5
70-percent-duration flow 7.3 39.9 23.1 3.4 4.9
75-percent-duration flow 6.0 32.9 20.5 3.0 4.3
80-percent-duration flow 4.9 27.6 17.8 2.7 3.6
85-percent-duration flow 3.9 21.6 15.4 2.4 2.9
90-percent-duration flow 2.9 12.5 13.7 2.2 2.6
95-percent-duration flow 2.3 5.1 10.8 1.8 2.2
99-percent-duration flow 1.6 3.5 6.5 1.4 1.9
Variability index 0.61 0.48 0.38 0.39 0.51
01604500 Patterson Creek near Headsville, WV, 1940–1996
1-day 2-year hydrologically based flow 6.03 39.0 22.3 6.29 9.65
1-day 5-year hydrologically based flow 3.31 20.8 12.7 3.43 5.45
1-day 10-year hydrologically based flow 2.40 14.7 8.97 2.48 4.12
3-day 2-year hydrologically based flow 6.29 41.8 24.1 6.56 10.3
3-day 5-year hydrologically based flow 3.53 22.1 13.8 3.64 5.89
3-day 10-year hydrologically based flow 2.60 15.5 9.80 2.67 4.51
7-day 2-year hydrologically based flow 6.76 48.1 28.2 7.12 11.5
7-day 5-year hydrologically based flow 3.88 24.6 16.4 4.04 6.69
7-day 10-year hydrologically based flow 2.91 16.9 11.6 3.01 5.15
14-day 2-year hydrologically based flow 7.56 59.6 34.0 8.17 13.0
14-day 5-year hydrologically based flow 4.39 29.1 19.6 4.64 7.52
14-day 10-year hydrologically based flow 3.35 19.5 14.0 3.51 5.82
30-day 2-year hydrologically based flow 9.76 95.1 53.8 11.1 20.1
30-day 5-year hydrologically based flow 5.88 46.9 31.2 6.47 10.1
30-day 10-year hydrologically based flow 4.62 31.8 23.0 5.02 7.10
1-day 3-year biologically based flow 1.96 9.98 15.9 2.13 3.10
4-day 3-year biologically based flow 2.40 11.4 19.1 2.87 4.51
EPA harmonic-mean flow 25.4 72.0 90.0 14.6 15.8
5-percent-duration flow 694 1,100 789 191 434
10-percent-duration flow 436 737 520 91.1 248
15-percent-duration flow 308 566 380 58.3 166
20-percent-duration flow 226 456 294 44.1 119
25-percent-duration flow 175 379 234 36.6 93.3
30-percent-duration flow 139 314 189 30.7 74.3
35-percent-duration flow 111 261 156 26.1 59.8
40-percent-duration flow 90.5 221 132 22.9 47.7
45-percent-duration flow 73.8 191 114 20.1 38.5
50-percent-duration flow 60.0 167 97.6 17.8 31.6
55-percent-duration flow 48.7 147 85.9 15.7 26.3
60-percent-duration flow 38.8 129 75.0 14.0 22.7
65-percent-duration flow 31.5 113 65.8 12.3 19.5
70-percent-duration flow 25.4 97.0 57.7 10.7 17.1
75-percent-duration flow 20.4 80.7 50.3 9.2 15.1
80-percent-duration flow 16.3 65.9 42.3 8.1 13.4
85-percent-duration flow 13.1 52.8 34.9 7.0 11.6
90-percent-duration flow 9.9 40.8 28.2 5.9 9.5
95-percent-duration flow 7.1 26.7 21.1 4.6 7.3
99-percent-duration flow 3.5 12.5 10.2 2.6 3.3
Variability index 0.63 0.49 0.48 0.48 0.55
01605500 South Branch Potomac River at Franklin, WV, 1946–1957
1-day 2-year hydrologically based flow 29.3 60.0 51.0 30.9 32.7
1-day 5-year hydrologically based flow 25.2 36.4 41.6 26.7 26.4
1-day 10-year hydrologically based flow 23.5 27.7 37.8 25.4 24.1
3-day 2-year hydrologically based flow 29.9 64.9 52.9 31.6 33.4
3-day 5-year hydrologically based flow 26.2 40.2 43.3 27.1 27.0
3-day 10-year hydrologically based flow 24.9 31.0 39.7 25.6 24.8
7-day 2-year hydrologically based flow 30.7 73.0 59.7 32.9 34.5
7-day 5-year hydrologically based flow 26.9 43.5 48.4 27.9 27.9
7-day 10-year hydrologically based flow 25.6 32.7 43.9 26.2 25.6
14-day 2-year hydrologically based flow 31.9 87.6 68.9 34.3 35.9
14-day 5-year hydrologically based flow 27.7 48.8 56.9 28.7 29.1
14-day 10-year hydrologically based flow 26.2 34.8 52.4 26.8 26.8
30-day 2-year hydrologically based flow 33.7 132 92.2 39.0 42.2
30-day 5-year hydrologically based flow 28.9 73.2 72.0 31.2 31.6
30-day 10-year hydrologically based flow 27.1 51.4 64.8 28.6 28.4
1-day 3-year biologically based flow 24.3 25.0 52.9 26.0 24.9
4-day 3-year biologically based flow 25.8 27.8 61.0 26.0 26.2
EPA harmonic-mean flow 73.7 119 148 52.2 50.4
5-percent-duration flow 527 740 524 221 385
10-percent-duration flow 366 539 357 138 222
15-percent-duration flow 289 448 282 108 163
20-percent-duration flow 237 390 241 87.4 128
25-percent-duration flow 200 349 211 74.6 108
30-percent-duration flow 173 316 188 65.8 93.1
35-percent-duration flow 149 292 174 59.9 81.7
40-percent-duration flow 128 268 161 55.2 73.2
45-percent-duration flow 112 245 149 51.6 66.2
50-percent-duration flow 96.6 224 138 48.1 59.5
55-percent-duration flow 83.2 205 128 45.8 53.6
60-percent-duration flow 72.2 190 118 43.5 47.4
65-percent-duration flow 63.3 173 109 41.4 42.2
70-percent-duration flow 55.2 152 101 39.4 38.9
75-percent-duration flow 48.0 128 92.7 37.5 36.4
80-percent-duration flow 42.1 107 84.1 35.5 34.1
85-percent-duration flow 38.0 79.7 75.5 33.5 32.2
90-percent-duration flow 34.3 58.4 66.8 31.4 30.6
95-percent-duration flow 30.7 42.6 56.9 28.7 28.9
99-percent-duration flow 26.7 29.2 43.7 25.1 25.8
Variability index 0.40 0.36 0.28 0.27 0.35
01606000 North Fork South Branch Potomac River at Cabins, WV, 1941–1954
1-day 2-year hydrologically based flow 15.2 114 74.7 16.0 24.5
1-day 5-year hydrologically based flow 8.75 65.9 58.1 9.31 10.8
1-day 10-year hydrologically based flow 6.49 47.8 51.9 6.89 7.06
3-day 2-year hydrologically based flow 15.7 121 83.3 16.7 25.2
3-day 5-year hydrologically based flow 9.04 68.3 64.0 9.74 11.1
3-day 10-year hydrologically based flow 6.67 48.8 56.3 7.20 7.25
7-day 2-year hydrologically based flow 17.4 140 96.6 19.0 26.4
7-day 5-year hydrologically based flow 9.61 74.6 72.1 10.7 11.5
7-day 10-year hydrologically based flow 6.97 51.5 62.2 7.78 7.41
14-day 2-year hydrologically based flow 19.7 175 127 23.9 29.5
14-day 5-year hydrologically based flow 10.5 87.0 92.3 12.9 12.3
14-day 10-year hydrologically based flow 7.39 58.6 77.5 9.00 7.88
30-day 2-year hydrologically based flow 23.4 270 200 36.4 40.4
30-day 5-year hydrologically based flow 11.8 166 151 17.7 15.7
30-day 10-year hydrologically based flow 8.22 130 131 11.5 9.86
1-day 3-year biologically based flow 4.98 25.9 65.0 6.16 4.97
4-day 3-year biologically based flow 5.49 33.5 76.7 6.78 5.50
EPA harmonic-mean flow 65.7 230 300 42.9 33.6
5-percent-duration flow 1,370 1,970 1,500 460 872
10-percent-duration flow 942 1,430 1,050 258 495
15-percent-duration flow 703 1,150 844 181 366
20-percent-duration flow 560 969 681 145 296
25-percent-duration flow 459 840 562 116 244
30-percent-duration flow 385 733 505 96.3 206
35-percent-duration flow 325 649 447 82.1 179
40-percent-duration flow 274 580 397 72.4 155
45-percent-duration flow 228 520 357 64.0 129
50-percent-duration flow 193 462 322 57.9 104
55-percent-duration flow 162 410 289 51.8 83.7
60-percent-duration flow 132 367 258 45.4 61.8
65-percent-duration flow 105 330 228 39.4 49.2
70-percent-duration flow 84.0 293 203 33.9 40.9
75-percent-duration flow 65.4 257 180 29.2 31.8
80-percent-duration flow 49.0 210 160 25.2 23.7
85-percent-duration flow 36.1 164 138 20.9 19.2
90-percent-duration flow 24.6 123 112 15.9 14.8
95-percent-duration flow 15.4 90.9 85.6 10.3 11.8
99-percent-duration flow 7.1 46.9 64.3 6.3 5.8
Variability index 0.60 0.40 0.37 0.48 0.59
01606500 South Branch Potomac River near Petersburg, WV, 1930–2002
1-day 2-year hydrologically based flow 72.6 239 175 76.7 90.3
1-day 5-year hydrologically based flow 56.9 152 129 58.4 67.9
1-day 10-year hydrologically based flow 51.2 117 109 51.5 60.7
3-day 2-year hydrologically based flow 74.1 253 187 78.4 93.9
3-day 5-year hydrologically based flow 57.9 161 137 59.5 69.9
3-day 10-year hydrologically based flow 52.0 125 115 52.4 62.1
7-day 2-year hydrologically based flow 76.2 284 211 82.2 101
7-day 5-year hydrologically based flow 59.6 178 152 61.9 72.9
7-day 10-year hydrologically based flow 53.8 138 127 54.4 64.1
14-day 2-year hydrologically based flow 79.8 336 259 88.7 110
14-day 5-year hydrologically based flow 62.3 201 182 65.7 76.7
14-day 10-year hydrologically based flow 56.7 154 149 57.6 66.0
30-day 2-year hydrologically based flow 88.1 498 374 102 152
30-day 5-year hydrologically based flow 68.3 295 246 73.8 92.3
30-day 10-year hydrologically based flow 62.3 223 194 65.5 72.9
1-day 3-year biologically based flow 49.0 88.9 144 50.0 55.9
4-day 3-year biologically based flow 50.5 99.9 170 52.6 59.1
EPA harmonic-mean flow 233 455 608 150 151
5-percent-duration flow 2,510 3,820 2,840 840 1,610
10-percent-duration flow 1,660 2,590 1,990 489 1,030
15-percent-duration flow 1,280 2,050 1,540 355 782
20-percent-duration flow 1,030 1,710 1,250 288 623
25-percent-duration flow 847 1,470 1,070 248 522
30-percent-duration flow 709 1,300 930 217 443
35-percent-duration flow 593 1,150 820 192 380
40-percent-duration flow 509 1,020 726 174 328
45-percent-duration flow 437 911 644 158 283
50-percent-duration flow 375 813 579 146 242
55-percent-duration flow 320 724 521 134 205
60-percent-duration flow 271 640 472 124 173
65-percent-duration flow 228 564 429 114 150
70-percent-duration flow 190 497 388 106 132
75-percent-duration flow 160 433 345 98.3 116
80-percent-duration flow 134 371 303 90.4 104
85-percent-duration flow 113 311 262 81.4 93.8
90-percent-duration flow 95.1 255 220 71.7 84.9
95-percent-duration flow 78.3 190 173 60.7 72.8
99-percent-duration flow 56.1 115 113 49.2 56.8
Variability index 0.48 0.39 0.37 0.34 0.43
01607500 South Fork South Branch Potomac River at Brandywine, WV, 1945–1996
1-day 2-year hydrologically based flow 5.02 23.5 13.4 5.22 8.15
1-day 5-year hydrologically based flow 3.08 12.9 8.64 3.16 5.14
1-day 10-year hydrologically based flow 2.36 8.91 6.80 2.41 4.11
3-day 2-year hydrologically based flow 5.20 25.7 14.4 5.44 8.41
3-day 5-year hydrologically based flow 3.21 14.1 9.20 3.29 5.25
3-day 10-year hydrologically based flow 2.49 9.90 7.20 2.53 4.19
7-day 2-year hydrologically based flow 5.47 30.3 16.5 5.86 9.01
7-day 5-year hydrologically based flow 3.40 16.2 10.6 3.52 5.59
7-day 10-year hydrologically based flow 2.64 11.1 8.25 2.69 4.47
14-day 2-year hydrologically based flow 6.02 35.2 20.3 6.48 10.0
14-day 5-year hydrologically based flow 3.77 17.9 12.8 3.87 6.11
14-day 10-year hydrologically based flow 2.97 12.1 9.97 3.01 4.86
30-day 2-year hydrologically based flow 7.03 54.1 34.2 8.15 15.5
30-day 5-year hydrologically based flow 4.53 27.0 19.5 4.88 8.31
30-day 10-year hydrologically based flow 3.69 17.9 14.6 3.85 6.17
1-day 3-year biologically based flow 1.98 5.74 10.9 1.91 3.39
4-day 3-year biologically based flow 2.08 6.52 13.7 2.07 4.00
EPA harmonic-mean flow 19.1 41.5 58.2 10.6 13.6
5-percent-duration flow 383 588 417 118 315
10-percent-duration flow 221 345 250 63.9 167
15-percent-duration flow 159 255 184 44.2 114
20-percent-duration flow 123 207 144 33.0 86.4
25-percent-duration flow 99.4 174 119 25.3 68.1
30-percent-duration flow 81.3 148 100 21.2 55.6
35-percent-duration flow 68.0 131 85.6 17.9 46.5
40-percent-duration flow 57.3 115 75.4 15.6 38.9
45-percent-duration flow 48.1 103 65.9 14.0 32.4
50-percent-duration flow 40.7 91.3 58.7 12.7 27.9
55-percent-duration flow 33.7 80.9 52.0 11.4 23.5
60-percent-duration flow 27.4 71.4 46.4 10.0 19.3
65-percent-duration flow 22.2 62.5 41.2 8.8 15.8
70-percent-duration flow 17.8 55.1 36.6 7.9 13.6
75-percent-duration flow 14.5 47.9 31.9 7.1 11.4
80-percent-duration flow 11.7 40.2 26.9 6.3 9.5
85-percent-duration flow 9.3 31.7 21.8 5.6 8.4
90-percent-duration flow 7.4 24.4 17.4 4.7 7.2
95-percent-duration flow 5.6 16.1 13.2 3.6 6.0
99-percent-duration flow 3.1 7.3 7.8 2.0 4.4
Variability index 0.57 0.45 0.45 0.45 0.54
01608000 South Fork South Branch Potomac River near Moorefield, WV, 1940–1996
1-day 2-year hydrologically based flow 15.7 58.7 41.5 17.2 21.8
1-day 5-year hydrologically based flow 10.4 33.9 28.6 11.2 14.1
1-day 10-year hydrologically based flow 8.29 24.7 23.3 8.73 11.5
3-day 2-year hydrologically based flow 16.1 62.1 44.0 17.7 22.7
3-day 5-year hydrologically based flow 10.7 35.8 30.3 11.5 14.7
3-day 10-year hydrologically based flow 8.55 26.0 24.6 8.99 12.0
7-day 2-year hydrologically based flow 16.8 71.7 49.3 18.4 24.1
7-day 5-year hydrologically based flow 11.2 40.2 33.8 12.0 15.5
7-day 10-year hydrologically based flow 9.09 28.6 27.5 9.46 12.7
14-day 2-year hydrologically based flow 17.8 81.8 59.2 19.8 26.7
14-day 5-year hydrologically based flow 12.2 43.6 40.0 12.9 17.0
14-day 10-year hydrologically based flow 10.1 30.6 32.2 10.4 13.9
30-day 2-year hydrologically based flow 20.4 120 95.2 23.8 38.0
30-day 5-year hydrologically based flow 14.1 62.4 58.5 15.4 21.4
30-day 10-year hydrologically based flow 11.9 43.2 44.8 12.7 16.4
1-day 3-year biologically based flow 7.80 14.9 33.0 7.86 11.0
4-day 3-year biologically based flow 8.44 18.4 40.7 8.82 11.4
EPA harmonic-mean flow 54.2 101 153 33.8 36.1
5-percent-duration flow 840 1,270 998 291 623
10-percent-duration flow 513 777 640 163 351
15-percent-duration flow 374 584 478 112 239
20-percent-duration flow 290 472 378 84.2 181
25-percent-duration flow 233 394 309 69.0 145
30-percent-duration flow 191 338 258 58.6 119
35-percent-duration flow 161 295 223 50.6 99.4
40-percent-duration flow 136 261 195 45.5 85.0
45-percent-duration flow 115 232 170 40.6 72.3
50-percent-duration flow 97.9 204 152 36.6 61.1
55-percent-duration flow 82.3 179 134 32.7 51.0
60-percent-duration flow 68.0 159 121 29.6 43.9
65-percent-duration flow 55.6 141 108 26.7 38.0
70-percent-duration flow 47.0 126 96.6 24.3 33.4
75-percent-duration flow 39.2 109 85.0 22.0 29.5
80-percent-duration flow 32.5 90.7 73.4 19.9 25.9
85-percent-duration flow 26.6 72.5 61.8 17.8 22.9
90-percent-duration flow 22.0 52.5 51.8 15.4 20.1
95-percent-duration flow 17.2 36.9 39.7 12.5 17.0
99-percent-duration flow 11.2 22.1 25.1 8.1 13.2
Variability index 0.53 0.45 0.42 0.41 0.49
01608500 South Branch Potomac River near Springfield, WV, 1930–2002
1-day 2-year hydrologically based flow 115 431 310 122 146
1-day 5-year hydrologically based flow 82.2 267 221 85.4 104
1-day 10-year hydrologically based flow 69.4 201 184 70.8 90.2
3-day 2-year hydrologically based flow 118 458 329 125 151
3-day 5-year hydrologically based flow 83.9 282 233 87.4 106
3-day 10-year hydrologically based flow 70.7 212 193 72.3 91.8
7-day 2-year hydrologically based flow 121 510 372 131 161
7-day 5-year hydrologically based flow 86.7 307 259 90.9 111
7-day 10-year hydrologically based flow 73.5 231 212 75.3 95.1
14-day 2-year hydrologically based flow 127 602 454 141 177
14-day 5-year hydrologically based flow 91.1 352 310 96.6 118
14-day 10-year hydrologically based flow 78.2 263 249 80.2 100
30-day 2-year hydrologically based flow 141 885 655 169 246
30-day 5-year hydrologically based flow 102 507 426 113 143
30-day 10-year hydrologically based flow 90.5 373 332 94.8 111
1-day 3-year biologically based flow 61.0 140 253 64.0 74.8
4-day 3-year biologically based flow 64.7 157 292 69.7 84.2
EPA harmonic-mean flow 378 767 1,040 241 241
5-percent-duration flow 4,750 7,030 5,310 1,640 3,010
10-percent-duration flow 3,090 4,770 3,620 920 1,860
15-percent-duration flow 2,300 3,700 2,820 663 1,350
20-percent-duration flow 1,820 3,070 2,290 528 1,070
25-percent-duration flow 1,490 2,640 1,920 443 888
30-percent-duration flow 1,240 2,300 1,650 381 750
35-percent-duration flow 1,040 2,010 1,430 335 637
40-percent-duration flow 893 1,780 1,270 302 542
45-percent-duration flow 767 1,590 1,130 271 465
50-percent-duration flow 654 1,410 1,010 247 393
55-percent-duration flow 554 1,250 914 223 331
60-percent-duration flow 467 1,110 826 204 280
65-percent-duration flow 389 987 752 186 244
70-percent-duration flow 321 871 679 170 214
75-percent-duration flow 265 758 607 156 188
80-percent-duration flow 221 649 530 141 169
85-percent-duration flow 183 541 452 127 152
90-percent-duration flow 152 428 378 110 134
95-percent-duration flow 121 310 295 88.6 114
99-percent-duration flow 80.0 193 188 64.6 85.8
Variability index 0.50 0.40 0.38 0.37 0.45
01610500 Cacapon River at Yellow Spring, WV, 1941–1951
1-day 2-year hydrologically based flow 25.2 77.7 51.7 25.5 34.0
1-day 5-year hydrologically based flow 21.3 45.5 43.5 21.8 25.9
1-day 10-year hydrologically based flow 19.8 33.8 39.8 20.5 22.2
3-day 2-year hydrologically based flow 26.2 81.4 55.6 26.4 35.0
3-day 5-year hydrologically based flow 22.2 48.5 46.5 22.4 26.8
3-day 10-year hydrologically based flow 20.5 36.4 42.5 20.9 23.0
7-day 2-year hydrologically based flow 27.3 89.5 65.3 27.4 37.0
7-day 5-year hydrologically based flow 23.0 51.5 53.0 23.0 26.9
7-day 10-year hydrologically based flow 21.2 38.6 47.8 21.4 23.3
14-day 2-year hydrologically based flow 29.3 102 77.3 30.1 42.7
14-day 5-year hydrologically based flow 23.9 59.1 61.7 24.4 27.8
14-day 10-year hydrologically based flow 21.6 44.1 56.0 22.2 23.3
30-day 2-year hydrologically based flow 32.9 151 128 36.7 49.7
30-day 5-year hydrologically based flow 25.6 83.1 92.1 27.6 30.2
30-day 10-year hydrologically based flow 22.6 59.3 77.6 24.2 24.7
1-day 3-year biologically based flow 20.9 30.0 45.9 21.0 23.0
4-day 3-year biologically based flow 21.0 35.5 51.3 21.0 23.0
EPA harmonic-mean flow 80.4 144 183 52.1 55.6
5-percent-duration flow 867 1,110 1,020 389 706
10-percent-duration flow 572 793 641 238 438
15-percent-duration flow 439 645 472 154 306
20-percent-duration flow 351 544 398 113 225
25-percent-duration flow 286 484 341 91.7 182
30-percent-duration flow 237 424 299 79.0 150
35-percent-duration flow 200 370 266 69.4 122
40-percent-duration flow 174 323 237 62.2 97.8
45-percent-duration flow 148 278 212 56.8 80.2
50-percent-duration flow 123 247 190 52.0 70.3
55-percent-duration flow 101 218 174 47.7 61.4
60-percent-duration flow 84.3 195 157 44.1 54.3
65-percent-duration flow 71.8 176 139 40.5 49.9
70-percent-duration flow 61.6 160 123 36.9 45.5
75-percent-duration flow 53.7 135 111 33.6 41.9
80-percent-duration flow 46.6 110 96.9 30.9 38.2
85-percent-duration flow 39.9 83.4 84.1 28.8 34.3
90-percent-duration flow 33.3 68.5 71.9 27.0 30.4
95-percent-duration flow 27.8 52.1 58.8 24.4 26.6
99-percent-duration flow 23.1 40.1 46.8 20.8 22.2
Variability index 0.48 0.41 0.37 0.37 0.45
01611500 Cacapon River near Great Cacapon, WV, 1933–1995
1-day 2-year hydrologically based flow 54.1 178 116 56.6 62.0
1-day 5-year hydrologically based flow 42.1 112 87.0 43.3 49.1
1-day 10-year hydrologically based flow 37.2 86.2 74.8 37.8 45.6
3-day 2-year hydrologically based flow 55.1 187 122 57.4 63.4
3-day 5-year hydrologically based flow 42.9 117 91.4 44.0 49.9
3-day 10-year hydrologically based flow 38.0 88.8 78.4 38.5 46.1
7-day 2-year hydrologically based flow 56.8 207 137 59.8 68.8
7-day 5-year hydrologically based flow 44.2 125 101 45.7 52.0
7-day 10-year hydrologically based flow 39.2 93.3 86.0 39.9 47.2
14-day 2-year hydrologically based flow 59.5 236 164 64.4 75.6
14-day 5-year hydrologically based flow 46.1 137 116 48.3 54.5
14-day 10-year hydrologically based flow 40.9 101 98.1 41.9 48.0
30-day 2-year hydrologically based flow 66.1 338 253 76.5 99.6
30-day 5-year hydrologically based flow 50.3 185 164 55.8 62.9
30-day 10-year hydrologically based flow 44.6 131 131 47.7 51.9
1-day 3-year biologically based flow 36.8 59.9 101 37.8 42.0
4-day 3-year biologically based flow 38.5 70.0 112 39.9 43.4
EPA harmonic-mean flow 159 301 424 103 108
5-percent-duration flow 2,170 3,190 2,620 609 1,480
10-percent-duration flow 1,380 2,100 1,760 334 851
15-percent-duration flow 992 1,600 1,330 238 580
20-percent-duration flow 765 1,280 1,080 191 443
25-percent-duration flow 609 1,070 888 163 350
30-percent-duration flow 502 914 743 142 287
35-percent-duration flow 419 790 632 128 242
40-percent-duration flow 352 688 547 116 202
45-percent-duration flow 296 612 477 107 170
50-percent-duration flow 249 542 417 97.9 146
55-percent-duration flow 207 479 372 91.1 126
60-percent-duration flow 173 427 331 84.3 112
65-percent-duration flow 146 382 297 78.6 99.9
70-percent-duration flow 123 341 265 73.5 90.9
75-percent-duration flow 106 295 234 68.5 82.5
80-percent-duration flow 91.2 248 203 63.6 75.8
85-percent-duration flow 78.5 199 173 58.8 69.2
90-percent-duration flow 67.8 159 144 53.4 62.5
95-percent-duration flow 56.6 122 115 47.2 54.7
99-percent-duration flow 42.8 68.2 81.7 35.6 43.5
Variability index 0.51 0.43 0.42 0.33 0.45
01614000 Back Creek near Jones Springs, WV, 1940–1953
1-day 2-year hydrologically based flow 7.90 55.1 25.2 8.04 13.9
1-day 5-year hydrologically based flow 5.08 32.5 19.3 5.21 7.89
1-day 10-year hydrologically based flow 4.07 24.4 16.8 4.22 5.78
3-day 2-year hydrologically based flow 8.35 59.5 27.5 8.49 14.5
3-day 5-year hydrologically based flow 5.36 35.2 21.0 5.45 8.34
3-day 10-year hydrologically based flow 4.28 26.5 18.2 4.39 6.17
7-day 2-year hydrologically based flow 9.02 66.4 33.3 9.21 16.8
7-day 5-year hydrologically based flow 5.85 38.4 25.0 5.95 9.16
7-day 10-year hydrologically based flow 4.73 28.8 21.3 4.83 6.65
14-day 2-year hydrologically based flow 10.4 78.9 42.2 11.0 20.3
14-day 5-year hydrologically based flow 6.44 44.9 32.0 6.75 9.92
14-day 10-year hydrologically based flow 5.07 33.3 27.4 5.30 6.98
30-day 2-year hydrologically based flow 14.1 118 75.4 17.0 29.8
30-day 5-year hydrologically based flow 8.25 66.7 54.1 10.6 13.1
30-day 10-year hydrologically based flow 6.22 49.0 45.2 8.24 8.88
1-day 3-year biologically based flow 3.88 14.0 19.9 3.88 4.76
4-day 3-year biologically based flow 4.55 22.5 23.7 4.91 5.32
EPA harmonic-mean flow 37.6 116 106 21.5 24.2
5-percent-duration flow 801 1,090 828 276 654
10-percent-duration flow 494 760 519 133 358
15-percent-duration flow 356 614 385 85.6 249
20-percent-duration flow 275 494 304 65.6 188
25-percent-duration flow 222 411 252 51.7 152
30-percent-duration flow 184 355 214 42.2 122
35-percent-duration flow 151 310 185 35.6 98.2
40-percent-duration flow 124 267 159 31.3 81.1
45-percent-duration flow 102 242 136 27.6 65.0
50-percent-duration flow 83.8 218 117 24.6 52.1
55-percent-duration flow 69.2 195 103 22.0 42.5
60-percent-duration flow 56.3 172 90.6 19.5 35.2
65-percent-duration flow 45.2 148 80.7 17.6 30.0
70-percent-duration flow 36.4 130 72.3 15.7 25.9
75-percent-duration flow 29.9 114 63.9 14.0 22.3
80-percent-duration flow 24.2 98.9 55.2 12.5 19.5
85-percent-duration flow 19.3 78.1 47.0 10.2 16.5
90-percent-duration flow 14.8 54.7 39.1 8.5 13.2
95-percent-duration flow 9.9 37.7 30.2 6.9 9.1
99-percent-duration flow 5.8 27.5 20.9 4.8 5.9
Variability index 0.59 0.43 0.44 0.47 0.57
01616500 Opequon Creek near Martinsburg, WV, 1949–1996
1-day 2-year hydrologically based flow 50.6 98.6 104 59.8 52.8
1-day 5-year hydrologically based flow 38.4 62.7 76.5 44.7 39.9
1-day 10-year hydrologically based flow 33.5 48.9 64.4 38.2 35.6
3-day 2-year hydrologically based flow 51.7 103 106 61.1 54.0
3-day 5-year hydrologically based flow 39.4 65.0 78.4 45.8 40.8
3-day 10-year hydrologically based flow 34.5 50.6 66.3 39.3 36.3
7-day 2-year hydrologically based flow 53.6 113 111 63.0 57.1
7-day 5-year hydrologically based flow 40.8 70.5 82.7 47.4 42.5
7-day 10-year hydrologically based flow 35.8 54.0 70.5 40.9 37.5
14-day 2-year hydrologically based flow 55.9 133 121 66.1 61.2
14-day 5-year hydrologically based flow 42.4 81.1 90.1 49.9 44.0
14-day 10-year hydrologically based flow 37.1 60.7 76.8 43.3 38.3
30-day 2-year hydrologically based flow 61.1 169 144 73.4 74.6
30-day 5-year hydrologically based flow 46.0 101 106 54.9 50.1
30-day 10-year hydrologically based flow 40.0 74.4 89.8 47.3 41.9
1-day 3-year biologically based flow 32.0 44.0 75.8 42.0 35.0
4-day 3-year biologically based flow 33.9 45.6 79.4 44.9 35.4
EPA harmonic-mean flow 115 152 201 95.1 79.0
5-percent-duration flow 700 1,030 773 273 547
10-percent-duration flow 468 696 514 195 360
15-percent-duration flow 362 548 410 161 281
20-percent-duration flow 300 461 345 142 228
25-percent-duration flow 256 399 302 129 190
30-percent-duration flow 224 351 269 119 161
35-percent-duration flow 198 314 245 111 135
40-percent-duration flow 176 282 224 104 112
45-percent-duration flow 157 258 206 96.7 98.1
50-percent-duration flow 140 236 190 91.5 89.1
55-percent-duration flow 125 216 176 86.4 81.0
60-percent-duration flow 113 196 163 81.3 74.5
65-percent-duration flow 101 180 151 76.9 69.1
70-percent-duration flow 91.2 164 140 72.4 65.0
75-percent-duration flow 82.4 146 129 67.9 60.8
80-percent-duration flow 73.9 127 118 63.2 56.7
85-percent-duration flow 65.5 108 109 58.5 52.6
90-percent-duration flow 57.5 87.7 97.8 52.9 48.1
95-percent-duration flow 49.0 65.7 84.2 46.4 43.0
99-percent-duration flow 37.5 44.2 62.5 36.5 33.8
Variability index 0.35 0.35 0.29 0.23 0.35
01636500 Shenandoah River at Millville, WV, 1930–2002
1-day 2-year hydrologically based flow 478 1,160 980 522 573
1-day 5-year hydrologically based flow 354 721 700 381 405
1-day 10-year hydrologically based flow 303 550 578 323 344
3-day 2-year hydrologically based flow 513 1,210 1,030 557 605
3-day 5-year hydrologically based flow 387 770 754 412 439
3-day 10-year hydrologically based flow 335 596 633 352 380
7-day 2-year hydrologically based flow 541 1,290 1,110 590 638
7-day 5-year hydrologically based flow 410 824 822 440 462
7-day 10-year hydrologically based flow 357 639 693 379 402
14-day 2-year hydrologically based flow 568 1,430 1,250 628 681
14-day 5-year hydrologically based flow 432 889 918 465 484
14-day 10-year hydrologically based flow 378 692 771 398 419
30-day 2-year hydrologically based flow 615 1,770 1,580 712 822
30-day 5-year hydrologically based flow 466 1,060 1,130 520 545
30-day 10-year hydrologically based flow 409 804 934 446 455
1-day 3-year biologically based flow 304 457 676 331 369
4-day 3-year biologically based flow 343 530 773 362 398
EPA harmonic-mean flow 1,230 1,710 2,280 912 878
5-percent-duration flow 8,040 11,400 8,970 3,730 6,510
10-percent-duration flow 5,480 7,670 6,310 2,440 4,180
15-percent-duration flow 4,300 6,120 4,990 1,870 3,140
20-percent-duration flow 3,530 5,200 4,170 1,600 2,510
25-percent-duration flow 2,980 4,520 3,610 1,410 2,140
30-percent-duration flow 2,570 4,030 3,190 1,260 1,840
35-percent-duration flow 2,270 3,610 2,850 1,150 1,590
40-percent-duration flow 2,000 3,220 2,600 1,050 1,380
45-percent-duration flow 1,770 2,920 2,370 977 1,190
50-percent-duration flow 1,590 2,640 2,190 900 1,070
55-percent-duration flow 1,410 2,410 2,020 842 955
60-percent-duration flow 1,250 2,190 1,870 792 872
65-percent-duration flow 1,100 1,980 1,720 741 790
70-percent-duration flow 970 1,770 1,600 691 732
75-percent-duration flow 863 1,570 1,470 641 677
80-percent-duration flow 764 1,390 1,340 590 620
85-percent-duration flow 678 1,160 1,210 538 563
90-percent-duration flow 585 908 1,060 482 502
95-percent-duration flow 482 707 872 416 436
99-percent-duration flow 367 488 629 324 361
Variability index 0.38 0.36 0.30 0.28 0.36
03050000 Tygart Valley River near Dailey, WV, 1932–1957
1-day 2-year hydrologically based flow 6.27 97.9 37.8 7.68 8.94
1-day 5-year hydrologically based flow 1.89 62.6 22.7 2.26 3.02
1-day 10-year hydrologically based flow 0.83 47.6 17.2 0.95 1.48
3-day 2-year hydrologically based flow 6.79 105 43.1 9.38 10.1
3-day 5-year hydrologically based flow 2.02 65.4 25.7 2.17 3.52
3-day 10-year hydrologically based flow 0.89 49.1 19.4 0.76 1.77
7-day 2-year hydrologically based flow 7.87 122 55.5 10.9 13.2
7-day 5-year hydrologically based flow 2.38 73.7 33.2 2.64 4.45
7-day 10-year hydrologically based flow 1.07 54.1 24.8 1.01 2.22
14-day 2-year hydrologically based flow 10.1 164 78.4 15.2 16.9
14-day 5-year hydrologically based flow 3.04 93.7 45.7 3.66 5.52
14-day 10-year hydrologically based flow 1.40 67.8 34.0 1.45 2.74
30-day 2-year hydrologically based flow 14.8 282 148 28.2 37.2
30-day 5-year hydrologically based flow 5.08 178 83.3 7.80 12.0
30-day 10-year hydrologically based flow 2.61 135 61.0 3.36 5.87
1-day 3-year biologically based flow 0.51 35.0 23.0 1.19 0.58
4-day 3-year biologically based flow 0.81 41.1 30.2 1.87 0.86
EPA harmonic-mean flow 21.5 230 171 15.9 8.78
5-percent-duration flow 1,260 1,920 1,200 560 812
10-percent-duration flow 818 1,300 812 285 515
15-percent-duration flow 606 999 646 191 374
20-percent-duration flow 471 822 533 147 286
25-percent-duration flow 392 694 437 119 227
30-percent-duration flow 323 604 378 96.0 189
35-percent-duration flow 268 539 327 80.7 159
40-percent-duration flow 225 483 277 68.1 132
45-percent-duration flow 189 431 243 58.3 111
50-percent-duration flow 159 383 214 49.3 90.9
55-percent-duration flow 132 345 189 42.1 74.5
60-percent-duration flow 109 310 167 35.5 61.1
65-percent-duration flow 87.7 278 147 29.8 49.4
70-percent-duration flow 69.0 248 129 24.4 39.1
75-percent-duration flow 53.5 219 113 19.3 30.3
80-percent-duration flow 40.0 189 96.4 15.0 21.9
85-percent-duration flow 27.8 155 76.7 10.7 15.5
90-percent-duration flow 17.3 125 59.5 6.8 8.8
95-percent-duration flow 7.4 91.2 40.8 3.6 3.5
99-percent-duration flow 0.9 44.7 22.4 0.5 0.2
Variability index 0.66 0.39 0.44 0.63 0.70
03050500 Tygart Valley River near Elkins, WV, 1946–2000
1-day 2-year hydrologically based flow 6.45 142 39.8 8.15 16.4
1-day 5-year hydrologically based flow 1.79 90.5 17.0 2.26 4.94
1-day 10-year hydrologically based flow 0.85 67.0 10.2 1.04 2.46
3-day 2-year hydrologically based flow 8.11 153 49.0 11.1 19.9
3-day 5-year hydrologically based flow 2.34 98.7 23.1 3.14 6.38
3-day 10-year hydrologically based flow 1.13 75.2 14.8 1.44 3.31
7-day 2-year hydrologically based flow 12.2 173 64.3 16.5 27.3
7-day 5-year hydrologically based flow 3.66 107 31.7 4.84 9.45
7-day 10-year hydrologically based flow 1.75 82.1 21.2 2.20 5.14
14-day 2-year hydrologically based flow 14.9 239 92.3 21.6 37.8
14-day 5-year hydrologically based flow 5.22 137 46.0 7.30 12.5
14-day 10-year hydrologically based flow 2.97 102 30.9 3.90 6.51
30-day 2-year hydrologically based flow 23.7 439 179 37.4 86.9
30-day 5-year hydrologically based flow 8.31 272 91.9 12.2 26.9
30-day 10-year hydrologically based flow 4.67 204 62.6 6.39 13.1
1-day 3-year biologically based flow 1.08 62.0 28.0 1.78 1.13
4-day 3-year biologically based flow 1.38 70.9 42.2 2.54 2.11
EPA harmonic-mean flow 36.5 333 270 25.8 15.6
5-percent-duration flow 1,960 2,930 1,990 773 1,600
10-percent-duration flow 1,270 1,980 1,280 425 1,000
15-percent-duration flow 939 1,500 977 286 739
20-percent-duration flow 753 1,230 810 220 575
25-percent-duration flow 617 1,060 685 174 458
30-percent-duration flow 506 921 581 143 372
35-percent-duration flow 426 808 499 119 315
40-percent-duration flow 352 711 429 98.8 262
45-percent-duration flow 298 638 371 82.8 223
50-percent-duration flow 247 569 324 68.3 186
55-percent-duration flow 209 507 283 57.4 159
60-percent-duration flow 172 452 246 47.2 132
65-percent-duration flow 141 400 210 40.1 106
70-percent-duration flow 111 352 180 32.9 83.5
75-percent-duration flow 83.4 310 151 26.3 65.1
80-percent-duration flow 61.6 267 124 20.0 49.4
85-percent-duration flow 42.4 222 98.2 14.4 33.6
90-percent-duration flow 26.1 183 70.9 8.4 19.2
95-percent-duration flow 11.7 135 42.8 4.2 8.5
99-percent-duration flow 2.8 81.8 18.0 1.6 2.3
Variability index 0.66 0.40 0.49 0.66 0.67
03051000 Tygart Valley River at Belington, WV, 1930–2002
1-day 2-year hydrologically based flow 16.6 227 71.9 19.8 28.3
1-day 5-year hydrologically based flow 5.69 145 37.5 6.47 9.86
1-day 10-year hydrologically based flow 2.86 109 26.1 3.12 5.35
3-day 2-year hydrologically based flow 17.8 244 83.0 21.7 32.1
3-day 5-year hydrologically based flow 6.28 153 43.4 7.28 11.1
3-day 10-year hydrologically based flow 3.31 114 30.1 3.65 6.06
7-day 2-year hydrologically based flow 21.6 277 109 27.7 42.2
7-day 5-year hydrologically based flow 7.41 167 57.0 8.97 14.4
7-day 10-year hydrologically based flow 3.81 125 39.5 4.36 7.69
14-day 2-year hydrologically based flow 26.8 375 158 37.2 57.5
14-day 5-year hydrologically based flow 9.28 223 81.0 12.1 18.8
14-day 10-year hydrologically based flow 4.95 169 55.4 6.00 9.66
30-day 2-year hydrologically based flow 41.7 677 290 67.6 133
30-day 5-year hydrologically based flow 14.2 434 155 21.1 41.6
30-day 10-year hydrologically based flow 7.51 336 109 10.3 20.1
1-day 3-year biologically based flow 2.96 90.0 51.9 4.39 4.37
4-day 3-year biologically based flow 3.50 111 68.5 5.79 5.06
EPA harmonic-mean flow 62.7 531 423 31.9 35.6
5-percent-duration flow 3,010 4,390 3,080 1,300 2,420
10-percent-duration flow 2,000 2,970 2,090 713 1,590
15-percent-duration flow 1,500 2,330 1,610 471 1,150
20-percent-duration flow 1,210 1,940 1,310 350 885
25-percent-duration flow 971 1,650 1,110 275 701
30-percent-duration flow 810 1,440 946 220 581
35-percent-duration flow 667 1,270 806 186 481
40-percent-duration flow 564 1,110 687 153 408
45-percent-duration flow 468 992 600 131 346
50-percent-duration flow 397 884 522 110 292
55-percent-duration flow 327 788 453 93.5 246
60-percent-duration flow 273 703 395 77.6 202
65-percent-duration flow 221 622 341 65.7 161
70-percent-duration flow 175 547 293 54.2 126
75-percent-duration flow 135 482 247 43.9 96.2
80-percent-duration flow 98.1 420 205 33.4 69.9
85-percent-duration flow 67.6 354 164 23.6 48.1
90-percent-duration flow 42.5 289 120 15.0 28.7
95-percent-duration flow 19.6 218 77.0 8.2 14.6
99-percent-duration flow 5.2 128 34.0 2.5 3.7
Variability index 0.65 0.39 0.48 0.64 0.66
03052000 Middle Fork River at Audra, WV, 1943–1964
1-day 2-year hydrologically based flow 4.05 112 33.3 5.15 9.56
1-day 5-year hydrologically based flow 1.04 79.0 19.1 1.43 2.36
1-day 10-year hydrologically based flow 0.49 65.7 14.3 0.69 1.05
3-day 2-year hydrologically based flow 4.46 121 39.2 5.76 10.8
3-day 5-year hydrologically based flow 1.14 83.8 22.0 1.60 2.54
3-day 10-year hydrologically based flow 0.53 69.1 16.3 0.77 1.09
7-day 2-year hydrologically based flow 5.65 140 52.1 7.50 13.9
7-day 5-year hydrologically based flow 1.37 92.9 29.8 2.02 3.02
7-day 10-year hydrologically based flow 0.62 74.9 22.3 0.96 1.24
14-day 2-year hydrologically based flow 7.61 193 70.3 11.0 19.4
14-day 5-year hydrologically based flow 1.75 120 40.0 2.82 3.98
14-day 10-year hydrologically based flow 0.77 92.3 29.9 1.30 1.53
30-day 2-year hydrologically based flow 12.4 315 136 20.8 43.9
30-day 5-year hydrologically based flow 3.09 240 73.5 5.77 9.24
30-day 10-year hydrologically based flow 1.41 208 53.1 2.72 3.49
1-day 3-year biologically based flow 0.42 49.9 22.0 0.55 0.55
4-day 3-year biologically based flow 0.54 64.7 33.7 0.72 1.22
EPA harmonic-mean flow 18.5 281 188 13.2 7.61
5-percent-duration flow 1,250 1,800 1,140 490 1,010
10-percent-duration flow 821 1,300 813 296 665
15-percent-duration flow 647 1,040 667 193 491
20-percent-duration flow 529 858 567 142 386
25-percent-duration flow 435 740 483 112 315
30-percent-duration flow 369 650 416 89.8 253
35-percent-duration flow 311 582 358 73.9 207
40-percent-duration flow 261 522 310 60.1 172
45-percent-duration flow 218 469 269 48.2 148
50-percent-duration flow 180 426 234 38.8 127
55-percent-duration flow 152 388 203 32.6 109
60-percent-duration flow 126 353 180 27.1 90.9
65-percent-duration flow 102 319 161 22.6 73.9
70-percent-duration flow 78.9 287 142 18.0 57.6
75-percent-duration flow 57.3 252 123 14.4 41.3
80-percent-duration flow 38.4 219 103 10.9 25.0
85-percent-duration flow 24.9 188 79.5 7.8 14.2
90-percent-duration flow 14.1 154 57.8 4.8 6.6
95-percent-duration flow 5.3 120 36.8 2.1 2.5
99-percent-duration flow 1.1 68.9 19.3 0.7 0.5
Variability index 0.71 0.35 0.45 0.69 0.77
03052500 Sand Run near Buckhannon, WV, 1948–2000
1-day 2-year hydrologically based flow 0.22 7.62 1.12 0.25 1.05
1-day 5-year hydrologically based flow 0.01 5.07 0.44 0.02 0.27
1-day 10-year hydrologically based flow 0.00 3.96 0.25 0.00 0.10
3-day 2-year hydrologically based flow 0.24 8.28 1.65 0.30 1.18
3-day 5-year hydrologically based flow 0.03 5.45 0.51 0.03 0.31
3-day 10-year hydrologically based flow 0.00 4.27 0.21 0.00 0.11
7-day 2-year hydrologically based flow 0.33 9.95 2.03 0.43 1.54
7-day 5-year hydrologically based flow 0.06 6.28 0.70 0.07 0.49
7-day 10-year hydrologically based flow 0.02 4.89 0.35 0.02 0.23
14-day 2-year hydrologically based flow 0.51 13.6 2.93 0.81 2.04
14-day 5-year hydrologically based flow 0.11 8.25 1.15 0.12 0.69
14-day 10-year hydrologically based flow 0.04 6.34 0.65 0.03 0.34
30-day 2-year hydrologically based flow 0.96 24.4 5.91 1.59 5.55
30-day 5-year hydrologically based flow 0.28 16.1 2.60 0.42 1.52
30-day 10-year hydrologically based flow 0.13 12.5 1.67 0.19 0.59
1-day 3-year biologically based flow 0.00 3.48 0.79 0.00 0.00
4-day 3-year biologically based flow 0.00 4.23 1.23 0.00 0.00
EPA harmonic-mean flow 1.15 19.4 9.81 0.50 0.74
5-percent-duration flow 101 156 103 39.6 91.6
10-percent-duration flow 65.8 99.4 65.4 21.9 56.7
15-percent-duration flow 48.9 74.9 49.8 14.5 42.4
20-percent-duration flow 39.8 61.3 40.9 10.4 34.3
25-percent-duration flow 32.5 53.2 33.3 7.7 27.7
30-percent-duration flow 27.4 46.5 28.5 6.2 23.3
35-percent-duration flow 23.0 41.0 23.8 5.0 19.2
40-percent-duration flow 19.3 36.9 20.6 4.0 16.0
45-percent-duration flow 16.0 33.4 17.3 3.3 13.1
50-percent-duration flow 13.2 30.3 15.1 2.8 10.7
55-percent-duration flow 10.7 27.5 12.9 2.3 8.9
60-percent-duration flow 8.3 25.1 10.8 2.0 7.3
65-percent-duration flow 6.6 22.7 8.8 1.6 5.8
70-percent-duration flow 4.9 20.4 7.3 1.3 4.5
75-percent-duration flow 3.6 18.0 5.8 0.9 3.5
80-percent-duration flow 2.6 15.6 4.3 0.6 2.6
85-percent-duration flow 1.8 13.2 3.1 0.4 1.8
90-percent-duration flow 1.0 10.7 2.1 0.2 1.2
95-percent-duration flow 0.4 8.0 1.2 0.1 0.5
99-percent-duration flow 0.0 4.7 0.4 0.0 0.0
Variability index 0.72 0.38 0.58 0.76 0.68
03053500 Buckhannon River at Hall, WV, 1930–2002
1-day 2-year hydrologically based flow 12.3 171 49.5 14.3 30.2
1-day 5-year hydrologically based flow 4.28 118 23.8 5.33 8.94
1-day 10-year hydrologically based flow 2.27 95.9 15.7 3.01 4.07
3-day 2-year hydrologically based flow 13.3 186 56.2 15.9 33.1
3-day 5-year hydrologically based flow 4.64 126 27.0 5.82 9.66
3-day 10-year hydrologically based flow 2.44 101 17.7 3.24 4.37
7-day 2-year hydrologically based flow 15.5 216 70.8 19.3 41.2
7-day 5-year hydrologically based flow 5.29 140 33.8 6.80 11.9
7-day 10-year hydrologically based flow 2.75 111 22.2 3.69 5.31
14-day 2-year hydrologically based flow 20.3 293 96.1 26.9 54.1
14-day 5-year hydrologically based flow 6.77 182 47.5 9.09 15.5
14-day 10-year hydrologically based flow 3.47 143 32.0 4.80 6.85
30-day 2-year hydrologically based flow 34.0 510 180 53.2 129
30-day 5-year hydrologically based flow 11.2 333 90.6 17.6 36.5
30-day 10-year hydrologically based flow 5.52 260 62.3 8.91 14.8
1-day 3-year biologically based flow 2.45 79.9 28.9 2.89 2.68
4-day 3-year biologically based flow 3.00 98.5 37.0 4.72 3.64
EPA harmonic-mean flow 42.4 437 271 31.6 17.7
5-percent-duration flow 2,150 3,030 2,090 940 1,880
10-percent-duration flow 1,450 2,120 1,430 551 1,190
15-percent-duration flow 1,100 1,640 1,120 387 901
20-percent-duration flow 866 1,370 918 288 722
25-percent-duration flow 736 1,190 768 220 595
30-percent-duration flow 610 1,050 649 177 499
35-percent-duration flow 522 934 556 147 410
40-percent-duration flow 435 832 480 121 352
45-percent-duration flow 370 753 412 103 294
50-percent-duration flow 307 682 355 86.9 251
55-percent-duration flow 257 623 310 73.9 209
60-percent-duration flow 211 563 268 61.9 175
65-percent-duration flow 172 504 232 51.2 143
70-percent-duration flow 137 449 198 42.3 113
75-percent-duration flow 105 395 166 33.9 88.9
80-percent-duration flow 77.2 340 135 26.1 66.6
85-percent-duration flow 53.9 285 106 19.4 45.5
90-percent-duration flow 34.0 229 77.6 13.1 27.8
95-percent-duration flow 16.4 178 47.4 7.3 11.7
99-percent-duration flow 3.9 107 19.5 2.7 0.8
Variability index 0.64 0.37 0.49 0.62 0.65
03054500 Tygart Valley River at Philippi, WV, 1941–2000
1-day 2-year hydrologically based flow 39.3 544 178 47.8 91.3
1-day 5-year hydrologically based flow 15.6 377 91.8 18.3 33.3
1-day 10-year hydrologically based flow 9.37 310 63.0 10.6 18.5
3-day 2-year hydrologically based flow 42.5 587 201 52.3 101
3-day 5-year hydrologically based flow 16.8 399 103 19.9 36.6
3-day 10-year hydrologically based flow 10.0 324 70.7 11.4 20.3
7-day 2-year hydrologically based flow 49.7 684 256 62.9 119
7-day 5-year hydrologically based flow 19.3 442 128 23.6 42.5
7-day 10-year hydrologically based flow 11.5 354 86.2 13.5 23.7
14-day 2-year hydrologically based flow 63.4 944 354 86.6 160
14-day 5-year hydrologically based flow 24.3 563 173 31.7 55.9
14-day 10-year hydrologically based flow 14.4 429 116 18.0 30.1
30-day 2-year hydrologically based flow 103 1,670 634 158 360
30-day 5-year hydrologically based flow 38.4 1,070 329 57.5 120
30-day 10-year hydrologically based flow 22.4 822 230 32.5 60.8
1-day 3-year biologically based flow 8.20 260 121 11.0 10.0
4-day 3-year biologically based flow 10.5 302 161 14.7 12.3
EPA harmonic-mean flow 224 1,400 1,030 131 118
5-percent-duration flow 6,800 9,770 6,720 2,930 5,940
10-percent-duration flow 4,580 6,720 4,700 1,740 3,930
15-percent-duration flow 3,490 5,270 3,610 1,230 2,850
20-percent-duration flow 2,810 4,450 2,980 902 2,290
25-percent-duration flow 2,370 3,850 2,530 692 1,940
30-percent-duration flow 2,000 3,400 2,180 550 1,630
35-percent-duration flow 1,720 3,020 1,910 449 1,370
40-percent-duration flow 1,470 2,690 1,670 371 1,170
45-percent-duration flow 1,250 2,430 1,460 310 981
50-percent-duration flow 1,040 2,210 1,280 265 819
55-percent-duration flow 851 2,020 1,110 225 688
60-percent-duration flow 699 1,840 958 189 570
65-percent-duration flow 557 1,670 828 159 455
70-percent-duration flow 438 1,470 706 132 362
75-percent-duration flow 332 1,300 581 109 281
80-percent-duration flow 246 1,120 463 85.4 208
85-percent-duration flow 173 917 365 62.8 152
90-percent-duration flow 111 726 265 40.3 89.6
95-percent-duration flow 54.8 548 176 24.5 46.6
99-percent-duration flow 16.1 339 75.6 11.2 12.6
Variability index 0.63 0.37 0.48 0.62 0.63
03056250 Three Fork Creek near Grafton, WV, 1986–2000
1-day 2-year hydrologically based flow 2.58 47.2 10.6 2.61 7.75
1-day 5-year hydrologically based flow 1.11 31.1 5.26 1.11 3.49
1-day 10-year hydrologically based flow 0.68 24.2 3.51 0.68 2.24
3-day 2-year hydrologically based flow 2.83 55.3 12.2 2.86 8.30
3-day 5-year hydrologically based flow 1.19 36.2 5.92 1.19 3.84
3-day 10-year hydrologically based flow 0.73 28.1 3.85 0.73 2.51
7-day 2-year hydrologically based flow 3.45 63.9 16.2 3.53 9.84
7-day 5-year hydrologically based flow 1.39 40.1 7.68 1.39 4.81
7-day 10-year hydrologically based flow 0.83 30.9 4.94 0.82 3.29
14-day 2-year hydrologically based flow 4.58 90.6 21.1 4.83 11.8
14-day 5-year hydrologically based flow 1.86 51.0 9.72 1.88 5.76
14-day 10-year hydrologically based flow 1.11 37.7 6.33 1.10 4.02
30-day 2-year hydrologically based flow 7.37 170 40.7 8.83 20.6
30-day 5-year hydrologically based flow 3.11 104 18.1 3.27 9.33
30-day 10-year hydrologically based flow 1.87 79.8 11.4 1.93 6.56
1-day 3-year biologically based flow 0.56 17.0 13.3 0.52 1.16
4-day 3-year biologically based flow 0.69 21.6 17.3 0.81 1.14
EPA harmonic-mean flow 15.0 116 93.6 6.86 9.85
5-percent-duration flow 692 1,030 640 211 608
10-percent-duration flow 432 688 402 114 371
15-percent-duration flow 325 540 310 74.6 272
20-percent-duration flow 254 440 242 55.0 215
25-percent-duration flow 202 378 201 42.0 175
30-percent-duration flow 169 331 173 31.9 146
35-percent-duration flow 142 293 150 25.6 121
40-percent-duration flow 121 254 131 21.1 97.9
45-percent-duration flow 101 225 116 17.8 80.1
50-percent-duration flow 82.7 201 101 15.2 66.7
55-percent-duration flow 67.1 180 87.3 12.7 54.3
60-percent-duration flow 52.2 159 74.2 10.1 41.2
65-percent-duration flow 38.8 141 61.7 8.1 30.8
70-percent-duration flow 28.1 127 50.8 6.5 24.6
75-percent-duration flow 20.8 113 41.0 5.1 18.1
80-percent-duration flow 14.9 99.4 30.8 3.9 13.5
85-percent-duration flow 10.1 85.0 23.0 2.9 10.5
90-percent-duration flow 6.6 70.3 17.0 2.0 8.1
95-percent-duration flow 3.2 53.4 10.0 1.3 5.8
99-percent-duration flow 1.1 30.2 3.6 0.7 2.4
Variability index 0.71 0.39 0.54 0.67 0.64
03057500 Skin Creek near Brownsville, WV, 1948–1960
1-day 2-year hydrologically based flow 0.18 9.04 0.96 0.20 0.45
1-day 5-year hydrologically based flow 0.00 5.20 0.44 0.00 0.00
1-day 10-year hydrologically based flow 0.00 3.75 0.30 0.00 0.00
3-day 2-year hydrologically based flow 0.25 9.84 1.13 0.27 0.44
3-day 5-year hydrologically based flow 0.00 5.48 0.53 0.00 0.00
3-day 10-year hydrologically based flow 0.00 3.91 0.37 0.00 0.00
7-day 2-year hydrologically based flow 0.34 12.4 1.79 0.15 1.29
7-day 5-year hydrologically based flow 0.00 6.82 0.81 0.00 0.00
7-day 10-year hydrologically based flow 0.00 4.72 0.54 0.00 0.00
14-day 2-year hydrologically based flow 0.21 22.5 2.41 0.42 3.04
14-day 5-year hydrologically based flow 0.00 11.6 1.21 0.00 0.05
14-day 10-year hydrologically based flow 0.00 7.63 0.88 0.00 0.00
30-day 2-year hydrologically based flow 0.49 40.9 6.76 1.11 4.79
30-day 5-year hydrologically based flow 0.01 30.3 2.86 0.07 0.19
30-day 10-year hydrologically based flow 0.00 25.1 1.87 0.00 0.00
1-day 3-year biologically based flow 0.00 2.53 0.39 0.00 0.00
4-day 3-year biologically based flow 0.00 3.09 0.50 0.00 0.00
EPA harmonic-mean flow 0.96 21.2 6.84 0.52 0.44
5-percent-duration flow 185 330 159 67.3 142
10-percent-duration flow 105 196 95.7 30.3 74.2
15-percent-duration flow 67.8 140 62.0 16.5 49.7
20-percent-duration flow 51.8 107 46.9 10.9 36.5
25-percent-duration flow 40.4 85.4 36.4 7.9 28.0
30-percent-duration flow 31.7 68.9 28.9 5.8 20.9
35-percent-duration flow 25.8 59.3 23.8 4.5 16.8
40-percent-duration flow 20.9 51.9 19.8 3.6 13.5
45-percent-duration flow 16.7 45.4 16.5 2.8 11.2
50-percent-duration flow 13.4 40.2 14.1 2.2 9.4
55-percent-duration flow 10.5 36.1 12.3 1.6 8.0
60-percent-duration flow 7.9 32.2 10.4 1.2 6.7
65-percent-duration flow 6.1 29.1 8.5 0.9 5.4
70-percent-duration flow 4.5 26.0 6.8 0.6 4.3
75-percent-duration flow 3.2 23.1 5.1 0.4 3.2
80-percent-duration flow 2.0 20.2 3.9 0.2 2.2
85-percent-duration flow 1.1 17.0 2.8 0.1 0.6
90-percent-duration flow 0.3 13.7 1.9 0.0 0.0
95-percent-duration flow 0.0 9.4 1.0 0.0 0.0
99-percent-duration flow 0.0 4.0 0.4 0.0 0.0
Variability index 0.59 0.45 0.65 0.72 0.60
03058000 WEST Fork River below Stonewall Jackson Dam near Weston, WV, 1948–1978
1-day 2-year hydrologically based flow 1.03 33.3 4.61 1.51 4.38
1-day 5-year hydrologically based flow 0.10 19.6 1.72 0.25 0.78
1-day 10-year hydrologically based flow 0.00 14.3 0.92 0.01 0.03
3-day 2-year hydrologically based flow 1.26 35.6 5.31 1.77 4.76
3-day 5-year hydrologically based flow 0.22 21.2 2.03 0.42 0.86
3-day 10-year hydrologically based flow 0.00 15.8 1.12 0.14 0.04
7-day 2-year hydrologically based flow 1.64 46.6 7.19 2.15 5.50
7-day 5-year hydrologically based flow 0.40 25.7 3.10 0.54 1.08
7-day 10-year hydrologically based flow 0.13 18.1 1.98 0.22 0.35
14-day 2-year hydrologically based flow 2.34 73.8 10.6 3.05 8.83
14-day 5-year hydrologically based flow 0.57 36.6 4.94 0.80 1.79
14-day 10-year hydrologically based flow 0.23 24.0 3.33 0.38 0.56
30-day 2-year hydrologically based flow 4.39 139 24.3 6.32 19.7
30-day 5-year hydrologically based flow 1.21 74.8 10.1 1.91 3.87
30-day 10-year hydrologically based flow 0.58 48.4 6.42 0.96 1.35
1-day 3-year biologically based flow 0.00 13.9 1.86 0.09 0.00
4-day 3-year biologically based flow 0.00 14.9 3.89 0.19 0.00
EPA harmonic-mean flow 5.51 71.6 35.6 2.94 2.90
5-percent-duration flow 710 1,110 697 225 575
10-percent-duration flow 419 712 403 106 332
15-percent-duration flow 286 535 268 62.4 229
20-percent-duration flow 211 409 199 44.0 163
25-percent-duration flow 163 330 155 33.2 126
30-percent-duration flow 128 281 125 25.9 100
35-percent-duration flow 104 241 102 20.5 80.7
40-percent-duration flow 84.2 208 83.4 15.9 67.2
45-percent-duration flow 67.2 180 71.9 13.3 54.7
50-percent-duration flow 55.0 158 61.3 10.9 44.0
55-percent-duration flow 43.8 140 52.0 8.9 36.5
60-percent-duration flow 34.1 124 43.2 7.4 29.8
65-percent-duration flow 26.7 110 35.3 6.0 24.7
70-percent-duration flow 19.8 95.6 28.8 4.7 19.3
75-percent-duration flow 14.4 81.9 22.6 3.5 14.6
80-percent-duration flow 9.5 68.3 16.2 2.6 10.1
85-percent-duration flow 6.1 54.7 11.7 1.7 4.7
90-percent-duration flow 3.4 43.3 7.8 0.8 2.3
95-percent-duration flow 1.1 31.6 4.7 0.4 0.6
99-percent-duration flow 0.2 14.1 1.7 0.1 0.1
Variability index 0.83 0.46 0.65 0.79 0.86
03058500 West Fork River at Butcherville, WV, 1934–1989
1-day 2-year hydrologically based flow 3.13 61.9 11.1 3.62 7.80
1-day 5-year hydrologically based flow 1.14 37.1 4.73 1.25 2.42
1-day 10-year hydrologically based flow 0.66 26.9 2.86 0.70 1.23
3-day 2-year hydrologically based flow 3.56 66.4 12.9 4.16 8.96
3-day 5-year hydrologically based flow 1.28 40.0 5.47 1.42 2.72
3-day 10-year hydrologically based flow 0.73 29.5 3.29 0.79 1.37
7-day 2-year hydrologically based flow 4.43 82.2 17.6 5.49 12.0
7-day 5-year hydrologically based flow 1.57 47.8 7.28 1.82 3.65
7-day 10-year hydrologically based flow 0.88 34.9 4.33 1.00 1.82
14-day 2-year hydrologically based flow 6.47 123 25.5 8.60 16.9
14-day 5-year hydrologically based flow 2.13 67.7 10.9 2.75 4.94
14-day 10-year hydrologically based flow 1.14 47.4 6.67 1.44 2.36
30-day 2-year hydrologically based flow 12.4 244 60.3 20.5 44.8
30-day 5-year hydrologically based flow 3.88 140 25.0 6.30 11.8
30-day 10-year hydrologically based flow 1.94 96.3 15.1 3.14 4.91
1-day 3-year biologically based flow 0.59 22.0 3.36 0.69 0.88
4-day 3-year biologically based flow 0.75 25.1 5.89 0.92 1.08
EPA harmonic-mean flow 16.8 151 64.1 9.24 9.27
5-percent-duration flow 1,270 1,830 1,240 544 1,040
10-percent-duration flow 738 1,210 728 248 598
15-percent-duration flow 511 911 505 143 412
20-percent-duration flow 383 717 380 99.9 311
25-percent-duration flow 307 582 302 76.0 246
30-percent-duration flow 248 489 243 60.8 198
35-percent-duration flow 201 420 195 51.5 162
40-percent-duration flow 163 366 158 43.6 132
45-percent-duration flow 131 321 133 37.0 108
50-percent-duration flow 106 280 112 31.2 89.0
55-percent-duration flow 85.8 250 93.9 26.0 72.3
60-percent-duration flow 69.0 222 80.9 21.3 58.6
65-percent-duration flow 55.2 199 68.3 17.4 47.9
70-percent-duration flow 44.1 174 56.7 13.9 38.4
75-percent-duration flow 33.9 148 46.3 10.3 30.0
80-percent-duration flow 24.7 124 36.5 7.1 22.0
85-percent-duration flow 16.6 103 26.9 4.7 13.9
90-percent-duration flow 9.4 81.0 18.6 2.9 7.2
95-percent-duration flow 3.7 58.4 10.7 1.6 2.7
99-percent-duration flow 1.1 29.1 3.3 0.8 0.6
Variability index 0.75 0.45 0.61 0.73 0.75
03059000 West Fork River at Clarksburg, WV, 1935–1983
1-day 2-year hydrologically based flow 2.22 138 16.4 3.13 10.7
1-day 5-year hydrologically based flow 0.00 77.4 3.85 0.00 0.00
1-day 10-year hydrologically based flow 0.00 52.2 1.49 0.00 0.00
3-day 2-year hydrologically based flow 2.87 147 20.3 3.85 12.8
3-day 5-year hydrologically based flow 0.00 82.4 4.93 0.00 0.26
3-day 10-year hydrologically based flow 0.00 57.7 1.95 0.00 0.00
7-day 2-year hydrologically based flow 4.21 182 31.6 5.79 20.8
7-day 5-year hydrologically based flow 0.00 96.0 8.47 0.23 1.19
7-day 10-year hydrologically based flow 0.00 65.1 3.56 0.00 0.00
14-day 2-year hydrologically based flow 7.56 255 51.4 10.5 29.5
14-day 5-year hydrologically based flow 0.57 128 16.1 1.14 2.34
14-day 10-year hydrologically based flow 0.00 84.6 7.74 0.00 0.00
30-day 2-year hydrologically based flow 20.3 495 122 31.2 75.5
30-day 5-year hydrologically based flow 2.22 271 43.5 6.38 17.3
30-day 10-year hydrologically based flow 0.00 180 22.9 1.96 3.39
1-day 3-year biologically based flow 0.00 40.0 1.78 0.00 0.00
4-day 3-year biologically based flow 0.00 49.6 4.31 0.00 0.00
EPA harmonic-mean flow 17.3 291 51.0 7.35 13.3
5-percent-duration flow 2,410 3,720 2,300 1,020 1,990
10-percent-duration flow 1,500 2,470 1,490 506 1,120
15-percent-duration flow 1,050 1,830 1,060 320 750
20-percent-duration flow 786 1,470 789 222 582
25-percent-duration flow 618 1,220 605 164 457
30-percent-duration flow 502 1,030 495 126 359
35-percent-duration flow 401 875 402 100 297
40-percent-duration flow 331 765 331 82.2 239
45-percent-duration flow 267 674 279 67.2 196
50-percent-duration flow 217 592 235 55.4 161
55-percent-duration flow 174 531 201 44.8 134
60-percent-duration flow 137 471 171 36.5 109
65-percent-duration flow 109 417 144 28.5 85.8
70-percent-duration flow 83.4 364 120 21.1 65.8
75-percent-duration flow 61.8 314 96.1 14.5 50.2
80-percent-duration flow 43.2 264 73.4 8.2 34.2
85-percent-duration flow 26.7 218 53.4 3.1 19.2
90-percent-duration flow 12.1 173 33.6 1.5 6.8
95-percent-duration flow 1.9 118 13.3 0.1 0.1
99-percent-duration flow 0.0 49.7 1.5 0.0 0.0
Variability index 0.89 0.45 0.65 1.13 1.19
03061000 West Fork River at Enterprise, WV, 1935–1983
1-day 2-year hydrologically based flow 39.7 316 115 41.7 58.4
1-day 5-year hydrologically based flow 18.9 186 59.2 20.5 27.8
1-day 10-year hydrologically based flow 12.0 134 38.7 13.4 18.0
3-day 2-year hydrologically based flow 42.1 336 124 44.2 63.0
3-day 5-year hydrologically based flow 20.5 199 64.3 22.3 29.9
3-day 10-year hydrologically based flow 13.2 146 42.5 14.9 19.5
7-day 2-year hydrologically based flow 47.0 400 152 51.1 76.5
7-day 5-year hydrologically based flow 23.6 222 77.2 26.5 35.7
7-day 10-year hydrologically based flow 15.6 159 50.9 18.2 22.9
14-day 2-year hydrologically based flow 57.5 535 193 67.6 92.6
14-day 5-year hydrologically based flow 30.6 290 98.6 35.7 43.3
14-day 10-year hydrologically based flow 21.5 206 66.3 24.8 28.2
30-day 2-year hydrologically based flow 82.5 982 330 111 170
30-day 5-year hydrologically based flow 44.3 564 165 57.7 73.1
30-day 10-year hydrologically based flow 31.3 397 111 39.7 45.3
1-day 3-year biologically based flow 9.51 89.7 69.9 9.98 15.0
4-day 3-year biologically based flow 15.9 142 65.7 19.0 19.9
EPA harmonic-mean flow 176 697 407 104 109
5-percent-duration flow 4,420 6,880 4,490 1,850 3,500
10-percent-duration flow 2,840 4,560 2,900 1,000 2,090
15-percent-duration flow 2,090 3,500 2,170 665 1,490
20-percent-duration flow 1,610 2,840 1,660 480 1,110
25-percent-duration flow 1,300 2,410 1,340 367 881
30-percent-duration flow 1,060 2,090 1,110 296 723
35-percent-duration flow 868 1,830 930 245 595
40-percent-duration flow 721 1,610 782 205 487
45-percent-duration flow 591 1,430 668 180 401
50-percent-duration flow 480 1,290 572 157 329
55-percent-duration flow 391 1,150 494 138 273
60-percent-duration flow 317 1,030 426 120 229
65-percent-duration flow 260 916 363 104 192
70-percent-duration flow 211 807 308 90.3 159
75-percent-duration flow 168 699 265 77.7 130
80-percent-duration flow 132 587 224 66.0 105
85-percent-duration flow 101 474 179 53.5 76.3
90-percent-duration flow 72.6 375 138 40.9 51.3
95-percent-duration flow 43.0 264 96.7 28.6 33.2
99-percent-duration flow 20.9 120 40.3 13.8 19.1
Variability index 0.62 0.42 0.51 0.54 0.61
03061500 Buffalo Creek at Barrackville, WV, 1934–1996
1-day 2-year hydrologically based flow 2.57 36.4 10.5 2.91 4.40
1-day 5-year hydrologically based flow 1.02 20.6 4.88 1.14 1.61
1-day 10-year hydrologically based flow 0.60 14.7 3.07 0.66 0.93
3-day 2-year hydrologically based flow 2.92 39.7 11.9 3.22 4.97
3-day 5-year hydrologically based flow 1.21 22.2 5.57 1.31 1.91
3-day 10-year hydrologically based flow 0.72 15.8 3.52 0.79 1.14
7-day 2-year hydrologically based flow 3.49 46.5 15.0 3.86 6.19
7-day 5-year hydrologically based flow 1.55 25.4 7.09 1.66 2.46
7-day 10-year hydrologically based flow 0.98 18.1 4.53 1.04 1.50
14-day 2-year hydrologically based flow 4.33 60.8 20.8 4.99 7.78
14-day 5-year hydrologically based flow 1.94 31.1 9.66 2.14 3.08
14-day 10-year hydrologically based flow 1.24 21.5 6.29 1.35 1.88
30-day 2-year hydrologically based flow 6.26 127 40.1 8.23 15.9
30-day 5-year hydrologically based flow 2.70 65.5 18.0 3.45 5.97
30-day 10-year hydrologically based flow 1.72 44.0 11.6 2.20 3.51
1-day 3-year biologically based flow 0.57 10.0 5.50 0.66 0.70
4-day 3-year biologically based flow 0.69 11.2 6.86 0.84 0.92
EPA harmonic-mean flow 13.1 81.4 55.4 6.83 7.86
5-percent-duration flow 711 1,160 744 236 485
10-percent-duration flow 415 715 451 106 271
15-percent-duration flow 285 533 311 62.8 186
20-percent-duration flow 213 419 232 45.4 137
25-percent-duration flow 168 341 183 35.2 109
30-percent-duration flow 134 286 154 28.4 88.6
35-percent-duration flow 110 243 129 23.1 72.2
40-percent-duration flow 90.5 213 110 19.0 60.4
45-percent-duration flow 73.2 186 94.3 16.1 49.5
50-percent-duration flow 60.0 164 80.5 13.5 39.7
55-percent-duration flow 47.7 144 69.2 11.3 32.4
60-percent-duration flow 37.0 127 58.3 9.2 25.7
65-percent-duration flow 28.7 112 49.1 7.8 19.8
70-percent-duration flow 21.9 98.4 40.8 6.5 15.2
75-percent-duration flow 16.6 85.2 33.2 5.5 11.9
80-percent-duration flow 12.0 72.6 26.1 4.5 9.1
85-percent-duration flow 8.3 59.7 20.2 3.5 6.7
90-percent-duration flow 5.4 46.4 15.1 2.7 4.4
95-percent-duration flow 3.1 30.0 9.6 1.8 2.7
99-percent-duration flow 1.1 14.6 3.7 0.7 0.9
Variability index 0.72 0.47 0.56 0.63 0.69
03065000 Dry Fork at Hendricks, WV, 1944–1993
1-day 2-year hydrologically based flow 26.3 203 96.7 28.6 55.7
1-day 5-year hydrologically based flow 13.5 149 56.9 14.4 25.5
1-day 10-year hydrologically based flow 9.29 127 42.7 9.76 16.4
3-day 2-year hydrologically based flow 27.9 213 111 31.1 62.0
3-day 5-year hydrologically based flow 14.3 154 64.3 15.5 27.1
3-day 10-year hydrologically based flow 9.87 131 47.6 10.5 17.0
7-day 2-year hydrologically based flow 32.3 241 146 37.3 76.2
7-day 5-year hydrologically based flow 16.3 166 81.9 18.3 32.7
7-day 10-year hydrologically based flow 11.2 139 58.8 12.3 20.2
14-day 2-year hydrologically based flow 39.4 314 199 48.8 98.5
14-day 5-year hydrologically based flow 19.7 195 107 23.4 40.7
14-day 10-year hydrologically based flow 13.6 154 75.0 15.6 24.6
30-day 2-year hydrologically based flow 59.2 533 345 83.4 201
30-day 5-year hydrologically based flow 28.1 326 188 39.7 79.3
30-day 10-year hydrologically based flow 18.7 246 132 25.6 44.8
1-day 3-year biologically based flow 7.09 117 68.8 8.00 12.0
4-day 3-year biologically based flow 9.13 132 87.8 10.7 13.4
EPA harmonic-mean flow 148 503 494 82.6 92.6
5-percent-duration flow 2,740 4,000 2,680 1,100 2,280
10-percent-duration flow 1,800 2,750 1,930 675 1,500
15-percent-duration flow 1,380 2,170 1,520 487 1,150
20-percent-duration flow 1,140 1,770 1,270 379 918
25-percent-duration flow 945 1,490 1,100 302 760
30-percent-duration flow 789 1,300 959 250 641
35-percent-duration flow 673 1,150 837 211 552
40-percent-duration flow 576 1,020 744 179 484
45-percent-duration flow 493 906 655 155 426
50-percent-duration flow 424 806 574 134 373
55-percent-duration flow 360 718 511 115 322
60-percent-duration flow 304 637 448 99.6 277
65-percent-duration flow 254 562 389 85.7 236
70-percent-duration flow 209 494 339 73.3 197
75-percent-duration flow 169 431 290 61.9 160
80-percent-duration flow 130 369 243 50.4 122
85-percent-duration flow 96.0 307 198 39.2 86.3
90-percent-duration flow 64.3 251 149 28.5 54.1
95-percent-duration flow 35.7 185 99.3 19.6 32.0
99-percent-duration flow 14.2 137 47.8 9.9 12.9
Variability index 0.56 0.40 0.43 0.52 0.55
03066000 Blackwater River at Davis, WV, 1930–2002
1-day 2-year hydrologically based flow 9.08 54.4 28.0 9.60 17.3
1-day 5-year hydrologically based flow 5.08 36.5 17.6 5.33 8.78
1-day 10-year hydrologically based flow 3.66 29.1 13.6 3.86 5.98
3-day 2-year hydrologically based flow 9.64 57.8 31.5 10.2 19.6
3-day 5-year hydrologically based flow 5.50 39.9 19.5 5.84 9.74
3-day 10-year hydrologically based flow 4.05 32.5 14.9 4.35 6.50
7-day 2-year hydrologically based flow 11.0 65.7 38.7 12.0 23.9
7-day 5-year hydrologically based flow 6.39 44.5 23.5 6.88 11.8
7-day 10-year hydrologically based flow 4.79 36.1 17.8 5.13 7.85
14-day 2-year hydrologically based flow 13.2 84.6 51.0 15.2 30.6
14-day 5-year hydrologically based flow 7.51 53.7 30.9 8.22 14.5
14-day 10-year hydrologically based flow 5.55 42.5 23.5 5.95 9.27
30-day 2-year hydrologically based flow 18.6 144 82.9 23.3 55.2
30-day 5-year hydrologically based flow 9.87 89.8 50.0 11.9 24.3
30-day 10-year hydrologically based flow 7.11 68.9 37.7 8.50 14.6
1-day 3-year biologically based flow 3.35 24.9 21.0 4.09 3.78
4-day 3-year biologically based flow 3.78 33.3 25.3 4.77 5.00
EPA harmonic-mean flow 45.8 134 123 25.6 30.9
5-percent-duration flow 718 1,040 684 361 577
10-percent-duration flow 479 740 492 212 376
15-percent-duration flow 361 574 388 150 284
20-percent-duration flow 289 465 319 111 229
25-percent-duration flow 239 393 270 87.4 193
30-percent-duration flow 204 340 233 71.2 165
35-percent-duration flow 174 296 203 59.2 145
40-percent-duration flow 149 260 177 51.2 125
45-percent-duration flow 129 234 158 43.8 109
50-percent-duration flow 110 210 140 37.5 94.7
55-percent-duration flow 95.1 189 123 32.5 82.2
60-percent-duration flow 80.8 169 109 27.9 71.6
65-percent-duration flow 67.5 151 96.4 23.9 61.4
70-percent-duration flow 56.4 132 84.3 20.4 51.6
75-percent-duration flow 45.9 116 72.4 17.3 42.9
80-percent-duration flow 36.1 101 61.7 14.8 34.0
85-percent-duration flow 26.9 85.9 51.6 12.2 24.8
90-percent-duration flow 18.3 67.0 40.5 9.3 17.5
95-percent-duration flow 11.9 51.0 29.0 6.8 12.1
99-percent-duration flow 5.4 34.1 15.6 4.2 4.6
Variability index 0.54 0.39 0.41 0.52 0.50
03069000 Shavers Fork at Parsons, WV, 1944–1993
1-day 2-year hydrologically based flow 28.9 138 94.3 32.4 57.7
1-day 5-year hydrologically based flow 13.8 98.1 55.7 15.6 25.4
1-day 10-year hydrologically based flow 9.02 82.2 41.5 10.2 15.4
3-day 2-year hydrologically based flow 30.7 148 104 35.2 64.4
3-day 5-year hydrologically based flow 14.6 103 60.7 16.8 28.0
3-day 10-year hydrologically based flow 9.52 85.4 44.8 11.0 16.8
7-day 2-year hydrologically based flow 35.9 169 129 42.8 76.1
7-day 5-year hydrologically based flow 16.8 113 73.8 20.1 32.7
7-day 10-year hydrologically based flow 10.8 92.7 53.7 12.9 19.4
14-day 2-year hydrologically based flow 44.1 219 164 55.0 97.8
14-day 5-year hydrologically based flow 20.5 133 95.5 25.9 40.9
14-day 10-year hydrologically based flow 13.1 103 70.0 16.7 23.7
30-day 2-year hydrologically based flow 65.3 364 268 90.1 188
30-day 5-year hydrologically based flow 30.1 221 165 43.9 77.0
30-day 10-year hydrologically based flow 19.2 166 125 28.7 42.2
1-day 3-year biologically based flow 7.00 75.0 63.0 10.9 13.0
4-day 3-year biologically based flow 10.0 91.1 83.4 13.4 14.1
EPA harmonic-mean flow 142 340 387 90.1 86.3
5-percent-duration flow 1,850 2,620 1,910 868 1,590
10-percent-duration flow 1,260 1,790 1,330 551 1,060
15-percent-duration flow 962 1,430 1,040 415 781
20-percent-duration flow 779 1,170 875 336 630
25-percent-duration flow 649 1,000 763 283 528
30-percent-duration flow 555 870 672 240 455
35-percent-duration flow 481 760 593 209 398
40-percent-duration flow 415 675 524 183 354
45-percent-duration flow 364 605 470 162 313
50-percent-duration flow 317 542 419 142 281
55-percent-duration flow 279 483 374 125 252
60-percent-duration flow 243 431 335 109 225
65-percent-duration flow 210 385 298 93.1 199
70-percent-duration flow 181 336 265 79.3 172
75-percent-duration flow 153 292 234 68.2 144
80-percent-duration flow 124 252 204 56.6 117
85-percent-duration flow 97.9 207 173 45.0 88.4
90-percent-duration flow 69.0 169 136 34.0 56.8
95-percent-duration flow 39.3 127 96.0 22.2 31.7
99-percent-duration flow 15.6 86.5 48.0 10.6 14.0
Variability index 0.49 0.40 0.38 0.47 0.48
03069500 Cheat River near Parsons, WV, 1930–2002
1-day 2-year hydrologically based flow 75.5 418 246 82.0 138
1-day 5-year hydrologically based flow 41.1 285 151 43.9 67.2
1-day 10-year hydrologically based flow 29.1 233 116 30.7 43.7
3-day 2-year hydrologically based flow 79.7 451 278 87.8 155
3-day 5-year hydrologically based flow 43.0 307 168 46.7 72.7
3-day 10-year hydrologically based flow 30.4 251 127 32.6 46.5
7-day 2-year hydrologically based flow 90.6 519 351 103 190
7-day 5-year hydrologically based flow 47.9 345 203 53.4 87.0
7-day 10-year hydrologically based flow 33.5 280 150 37.1 54.5
14-day 2-year hydrologically based flow 112 685 463 133 243
14-day 5-year hydrologically based flow 57.5 426 265 67.4 107
14-day 10-year hydrologically based flow 39.5 336 193 46.3 64.8
30-day 2-year hydrologically based flow 163 1,200 772 220 468
30-day 5-year hydrologically based flow 79.3 752 457 105 191
30-day 10-year hydrologically based flow 53.0 575 339 70.2 108
1-day 3-year biologically based flow 26.9 230 187 30.9 36.0
4-day 3-year biologically based flow 33.6 265 226 37.2 40.6
EPA harmonic-mean flow 377 1,080 1,110 225 231
5-percent-duration flow 5,880 8,370 5,890 2,960 4,800
10-percent-duration flow 3,980 5,900 4,210 1,790 3,170
15-percent-duration flow 3,060 4,600 3,340 1,310 2,390
20-percent-duration flow 2,480 3,780 2,810 994 1,950
25-percent-duration flow 2,090 3,230 2,450 786 1,640
30-percent-duration flow 1,780 2,840 2,140 650 1,380
35-percent-duration flow 1,520 2,510 1,890 545 1,200
40-percent-duration flow 1,310 2,210 1,660 460 1,040
45-percent-duration flow 1,120 1,990 1,470 400 899
50-percent-duration flow 961 1,780 1,300 347 785
55-percent-duration flow 818 1,600 1,150 302 680
60-percent-duration flow 692 1,430 1,010 260 590
65-percent-duration flow 585 1,260 882 223 504
70-percent-duration flow 486 1,100 769 193 427
75-percent-duration flow 398 953 664 163 351
80-percent-duration flow 316 819 564 134 278
85-percent-duration flow 237 680 464 106 206
90-percent-duration flow 167 530 358 79.0 137
95-percent-duration flow 96.1 398 248 56.1 82.8
99-percent-duration flow 39.9 273 129 28.7 30.5
Variability index 0.54 0.40 0.41 0.52 0.52
03070000 Cheat River at Rowlesburg, WV, 1930–1996
1-day 2-year hydrologically based flow 93.1 612 325 99.6 169
1-day 5-year hydrologically based flow 49.6 415 202 54.3 78.6
1-day 10-year hydrologically based flow 34.2 337 156 38.4 49.5
3-day 2-year hydrologically based flow 97.0 660 361 105 186
3-day 5-year hydrologically based flow 51.5 447 219 57.2 83.8
3-day 10-year hydrologically based flow 35.5 364 167 40.5 52.2
7-day 2-year hydrologically based flow 109 757 451 123 226
7-day 5-year hydrologically based flow 56.3 509 263 64.9 98.5
7-day 10-year hydrologically based flow 38.4 415 195 45.4 59.8
14-day 2-year hydrologically based flow 135 996 596 162 293
14-day 5-year hydrologically based flow 68.0 619 339 83.3 121
14-day 10-year hydrologically based flow 45.8 486 248 57.6 70.9
30-day 2-year hydrologically based flow 201 1,700 1,010 276 605
30-day 5-year hydrologically based flow 96.7 1,060 591 133 235
30-day 10-year hydrologically based flow 63.6 809 437 87.3 127
1-day 3-year biologically based flow 35.0 309 229 40.9 41.9
4-day 3-year biologically based flow 39.6 380 280 50.6 47.8
EPA harmonic-mean flow 471 1,550 1,470 283 276
5-percent-duration flow 8,030 11,400 7,860 3,690 6,590
10-percent-duration flow 5,430 7,950 5,690 2,260 4,450
15-percent-duration flow 4,160 6,290 4,540 1,660 3,370
20-percent-duration flow 3,380 5,210 3,770 1,270 2,710
25-percent-duration flow 2,810 4,450 3,240 1,020 2,230
30-percent-duration flow 2,390 3,880 2,830 834 1,920
35-percent-duration flow 2,060 3,410 2,490 699 1,660
40-percent-duration flow 1,760 3,050 2,210 592 1,440
45-percent-duration flow 1,530 2,730 1,960 504 1,250
50-percent-duration flow 1,300 2,440 1,740 433 1,070
55-percent-duration flow 1,120 2,200 1,530 379 932
60-percent-duration flow 942 1,970 1,340 329 798
65-percent-duration flow 783 1,750 1,190 283 677
70-percent-duration flow 648 1,560 1,030 242 571
75-percent-duration flow 522 1,370 888 203 467
80-percent-duration flow 408 1,180 752 166 357
85-percent-duration flow 305 981 616 130 258
90-percent-duration flow 208 768 472 97.4 168
95-percent-duration flow 116 573 313 68.3 97.1
99-percent-duration flow 49.0 395 180 36.2 31.0
Variability index 0.55 0.39 0.42 0.52 0.54
03070500 Big Sandy Creek at Rockville, WV, 1930–2002
1-day 2-year hydrologically based flow 10.6 112 38.1 9.89 23.5
1-day 5-year hydrologically based flow 4.48 75.3 19.8 4.74 8.27
1-day 10-year hydrologically based flow 2.43 60.1 13.8 3.07 4.04
3-day 2-year hydrologically based flow 11.4 121 43.8 10.7 25.9
3-day 5-year hydrologically based flow 4.79 81.6 22.4 5.14 8.79
3-day 10-year hydrologically based flow 2.58 65.6 15.4 3.37 4.23
7-day 2-year hydrologically based flow 13.5 138 55.9 12.8 31.6
7-day 5-year hydrologically based flow 5.48 91.7 28.3 5.94 10.7
7-day 10-year hydrologically based flow 2.88 74.1 19.2 3.83 5.04
14-day 2-year hydrologically based flow 16.8 178 75.3 16.8 39.6
14-day 5-year hydrologically based flow 6.74 111 38.2 7.49 13.2
14-day 10-year hydrologically based flow 3.59 87.7 26.0 4.73 6.24
30-day 2-year hydrologically based flow 23.5 306 136 27.5 75.8
30-day 5-year hydrologically based flow 9.90 195 71.7 11.9 24.2
30-day 10-year hydrologically based flow 5.54 151 50.3 7.39 11.4
1-day 3-year biologically based flow 2.49 49.9 27.9 4.30 2.76
4-day 3-year biologically based flow 3.27 64.5 36.1 4.86 3.94
EPA harmonic-mean flow 39.0 280 224 26.0 17.8
5-percent-duration flow 1,500 2,170 1,480 555 1,230
10-percent-duration flow 957 1,500 1,030 315 805
15-percent-duration flow 755 1,170 819 212 609
20-percent-duration flow 610 965 679 156 483
25-percent-duration flow 506 820 571 120 407
30-percent-duration flow 427 713 491 95.3 336
35-percent-duration flow 360 636 431 78.9 286
40-percent-duration flow 303 571 376 65.3 237
45-percent-duration flow 253 514 331 53.9 202
50-percent-duration flow 210 462 289 45.8 168
55-percent-duration flow 172 414 251 38.7 142
60-percent-duration flow 140 369 215 33.0 116
65-percent-duration flow 111 326 183 27.8 93.8
70-percent-duration flow 86.4 286 155 22.9 72.6
75-percent-duration flow 64.6 248 130 18.9 54.3
80-percent-duration flow 46.5 214 106 15.2 40.2
85-percent-duration flow 32.4 177 82.3 12.0 29.5
90-percent-duration flow 20.7 144 60.9 9.2 19.7
95-percent-duration flow 11.6 109 38.4 6.4 11.4
99-percent-duration flow 4.7 68.2 15.6 2.8 2.4
Variability index 0.65 0.39 0.48 0.59 0.62
03071000 Cheat River near Pisgah, WV, 1932–1957
1-day 2-year hydrologically based flow 130 886 551 132 192
1-day 5-year hydrologically based flow 64.9 605 320 72.0 85.7
1-day 10-year hydrologically based flow 42.6 497 235 51.9 52.3
3-day 2-year hydrologically based flow 137 948 609 141 205
3-day 5-year hydrologically based flow 68.0 644 350 75.8 89.9
3-day 10-year hydrologically based flow 44.4 529 254 54.4 54.7
7-day 2-year hydrologically based flow 154 1,080 726 164 252
7-day 5-year hydrologically based flow 73.3 720 419 84.9 101
7-day 10-year hydrologically based flow 46.9 585 304 60.0 59.2
14-day 2-year hydrologically based flow 189 1,450 911 213 317
14-day 5-year hydrologically based flow 85.7 895 547 107 120
14-day 10-year hydrologically based flow 53.6 697 410 74.7 67.6
30-day 2-year hydrologically based flow 273 2,330 1,510 378 609
30-day 5-year hydrologically based flow 120 1,620 919 177 220
30-day 10-year hydrologically based flow 72.4 1,330 693 115 114
1-day 3-year biologically based flow 41.0 399 299 46.8 40.9
4-day 3-year biologically based flow 49.6 484 357 65.4 68.7
EPA harmonic-mean flow 597 2,280 1,910 415 301
5-percent-duration flow 10,000 15,800 9,440 5,100 7,140
10-percent-duration flow 6,900 11,200 7,020 3,140 4,560
15-percent-duration flow 5,380 8,310 5,660 2,340 3,720
20-percent-duration flow 4,440 7,100 4,820 1,830 3,030
25-percent-duration flow 3,770 6,040 4,220 1,440 2,510
30-percent-duration flow 3,260 5,360 3,740 1,160 2,120
35-percent-duration flow 2,780 4,870 3,330 988 1,860
40-percent-duration flow 2,400 4,420 3,000 845 1,610
45-percent-duration flow 2,070 4,010 2,690 723 1,410
50-percent-duration flow 1,790 3,610 2,420 634 1,210
55-percent-duration flow 1,510 3,250 2,170 549 1,060
60-percent-duration flow 1,260 2,960 1,920 470 904
65-percent-duration flow 1,060 2,700 1,690 406 759
70-percent-duration flow 882 2,430 1,470 341 635
75-percent-duration flow 712 2,080 1,290 278 512
80-percent-duration flow 553 1,810 1,120 226 365
85-percent-duration flow 401 1,500 949 183 252
90-percent-duration flow 260 1,160 766 138 170
95-percent-duration flow 148 842 499 97.1 101
99-percent-duration flow 63.3 504 286 50.3 23.1
Variability index 0.55 0.37 0.38 0.52 0.55
03112000 Wheeling Creek at Elm Grove, WV, 1942–1980
1-day 2-year hydrologically based flow 2.25 80.9 29.4 2.53 6.52
1-day 5-year hydrologically based flow 0.68 35.9 13.5 0.74 1.64
1-day 10-year hydrologically based flow 0.36 21.1 8.01 0.37 0.78
3-day 2-year hydrologically based flow 2.64 86.1 34.0 2.90 7.64
3-day 5-year hydrologically based flow 0.82 38.0 15.5 0.89 1.95
3-day 10-year hydrologically based flow 0.43 22.8 9.21 0.46 0.91
7-day 2-year hydrologically based flow 3.29 96.7 43.1 3.66 9.43
7-day 5-year hydrologically based flow 1.09 46.2 20.2 1.23 2.42
7-day 10-year hydrologically based flow 0.60 30.2 12.2 0.68 1.12
14-day 2-year hydrologically based flow 5.10 129 59.1 5.85 13.7
14-day 5-year hydrologically based flow 1.69 59.8 28.8 1.99 3.47
14-day 10-year hydrologically based flow 0.91 38.8 18.2 1.11 1.53
30-day 2-year hydrologically based flow 8.77 234 104 11.5 28.0
30-day 5-year hydrologically based flow 2.81 110 51.0 3.82 6.83
30-day 10-year hydrologically based flow 1.47 70.2 34.0 2.05 2.88
1-day 3-year biologically based flow 0.30 11.0 21.0 0.55 0.35
4-day 3-year biologically based flow 0.37 16.7 28.0 0.84 0.46
EPA harmonic-mean flow 13.9 131 165 8.96 6.13
5-percent-duration flow 1,320 2,030 1,420 423 820
10-percent-duration flow 858 1,400 922 213 507
15-percent-duration flow 621 1,080 701 134 350
20-percent-duration flow 472 883 544 95.2 261
25-percent-duration flow 374 744 441 73.2 200
30-percent-duration flow 302 637 371 57.9 155
35-percent-duration flow 241 556 318 45.8 126
40-percent-duration flow 196 488 274 36.8 102
45-percent-duration flow 157 435 235 30.0 82.1
50-percent-duration flow 126 387 202 24.3 68.4
55-percent-duration flow 99.4 339 175 19.6 57.2
60-percent-duration flow 77.4 292 152 15.7 48.1
65-percent-duration flow 60.5 255 130 12.7 39.1
70-percent-duration flow 46.8 219 111 10.0 30.2
75-percent-duration flow 34.3 186 94.3 7.8 22.2
80-percent-duration flow 23.4 154 78.0 5.8 16.2
85-percent-duration flow 14.7 112 60.6 3.9 8.7
90-percent-duration flow 7.8 76.5 44.3 2.6 4.3
95-percent-duration flow 3.1 53.6 27.8 1.5 1.9
99-percent-duration flow 0.9 21.4 10.9 0.5 0.6
Variability index 0.79 0.47 0.51 0.73 0.78
03114500 Middle Island Creek at Little, WV, 1930–1995
1-day 2-year hydrologically based flow 3.08 138 28.4 4.48 7.14
1-day 5-year hydrologically based flow 0.68 65.3 9.65 1.01 1.69
1-day 10-year hydrologically based flow 0.27 34.0 4.57 0.39 0.70
3-day 2-year hydrologically based flow 3.46 149 30.1 4.97 7.78
3-day 5-year hydrologically based flow 0.79 67.8 10.7 1.10 1.93
3-day 10-year hydrologically based flow 0.32 35.2 5.49 0.42 0.84
7-day 2-year hydrologically based flow 4.14 174 39.7 6.05 9.58
7-day 5-year hydrologically based flow 0.97 74.2 13.6 1.38 2.41
7-day 10-year hydrologically based flow 0.40 39.0 6.88 0.55 1.05
14-day 2-year hydrologically based flow 5.79 214 55.8 8.96 14.5
14-day 5-year hydrologically based flow 1.45 91.0 20.4 2.09 3.99
14-day 10-year hydrologically based flow 0.63 53.5 11.3 0.85 1.83
30-day 2-year hydrologically based flow 11.6 521 125 22.6 43.8
30-day 5-year hydrologically based flow 3.14 230 46.9 6.08 11.0
30-day 10-year hydrologically based flow 1.43 129 26.6 2.67 4.64
1-day 3-year biologically based flow 0.17 27.9 11.9 0.19 0.27
4-day 3-year biologically based flow 0.23 40.0 15.9 0.56 0.46
EPA harmonic-mean flow 12.8 127 139 7.11 6.40
5-percent-duration flow 2,940 4,820 2,880 912 2,070
10-percent-duration flow 1,560 2,950 1,750 424 1,120
15-percent-duration flow 1,070 2,120 1,190 260 757
20-percent-duration flow 807 1,570 873 178 543
25-percent-duration flow 625 1,250 676 128 405
30-percent-duration flow 485 1,060 550 98.2 311
35-percent-duration flow 388 887 443 78.0 252
40-percent-duration flow 313 776 375 61.5 202
45-percent-duration flow 249 664 312 49.7 160
50-percent-duration flow 201 589 266 39.8 128
55-percent-duration flow 156 515 221 31.3 99.6
60-percent-duration flow 119 450 186 26.0 76.7
65-percent-duration flow 89.5 390 152 21.0 58.2
70-percent-duration flow 65.5 335 127 16.9 43.2
75-percent-duration flow 46.6 285 101 13.2 30.9
80-percent-duration flow 31.6 237 75.9 9.9 21.2
85-percent-duration flow 20.5 189 54.9 6.8 13.8
90-percent-duration flow 11.8 134 36.5 4.0 6.1
95-percent-duration flow 4.4 85.2 20.6 1.5 2.3
99-percent-duration flow 0.4 32.9 6.9 0.2 0.2
Variability index 0.84 0.51 0.64 0.80 0.87
03152000 Little Kanawha River at Glenville, WV, 1943–1978
1-day 2-year hydrologically based flow 5.89 153 30.8 7.40 15.7
1-day 5-year hydrologically based flow 1.36 88.7 15.6 1.81 4.15
1-day 10-year hydrologically based flow 0.55 63.2 10.8 0.74 1.80
3-day 2-year hydrologically based flow 6.51 170 35.0 8.15 18.1
3-day 5-year hydrologically based flow 1.59 97.9 17.3 2.11 4.89
3-day 10-year hydrologically based flow 0.68 69.5 11.7 0.91 2.16
7-day 2-year hydrologically based flow 7.68 212 44.3 9.56 23.3
7-day 5-year hydrologically based flow 2.00 116 21.2 2.67 6.29
7-day 10-year hydrologically based flow 0.90 79.8 14.0 1.25 2.76
14-day 2-year hydrologically based flow 10.4 300 65.6 13.6 35.9
14-day 5-year hydrologically based flow 2.57 156 30.0 3.62 9.24
14-day 10-year hydrologically based flow 1.13 104 19.2 1.65 3.80
30-day 2-year hydrologically based flow 19.0 531 149 28.9 83.0
30-day 5-year hydrologically based flow 5.00 304 64.7 8.29 18.4
30-day 10-year hydrologically based flow 2.24 207 39.9 3.92 6.68
1-day 3-year biologically based flow 0.27 43.9 17.9 0.70 0.57
4-day 3-year biologically based flow 0.37 52.2 20.9 0.88 1.25
EPA harmonic-mean flow 22.0 334 192 12.3 10.8
5-percent-duration flow 2,600 3,690 2,480 927 2,100
10-percent-duration flow 1,520 2,570 1,530 449 1,200
15-percent-duration flow 1,100 1,940 1,090 286 840
20-percent-duration flow 848 1,540 817 194 646
25-percent-duration flow 670 1,300 643 141 508
30-percent-duration flow 540 1,100 522 108 402
35-percent-duration flow 446 940 432 89.6 334
40-percent-duration flow 361 823 367 73.6 272
45-percent-duration flow 296 733 314 61.4 219
50-percent-duration flow 237 651 268 50.6 180
55-percent-duration flow 191 580 231 41.9 146
60-percent-duration flow 152 523 200 34.7 117
65-percent-duration flow 118 470 172 28.6 92.3
70-percent-duration flow 88.8 416 146 23.6 71.1
75-percent-duration flow 64.8 361 122 18.9 53.2
80-percent-duration flow 45.7 307 96.4 14.8 38.3
85-percent-duration flow 29.9 253 72.8 10.2 24.7
90-percent-duration flow 18.7 195 49.4 6.6 13.3
95-percent-duration flow 8.1 141 26.7 3.1 4.1
99-percent-duration flow 1.2 69.0 12.5 0.6 0.6
Variability index 0.75 0.42 0.58 0.72 0.79
03153000 Steer Creek near Grantsville, WV, 1956–1974
1-day 2-year hydrologically based flow 0.55 37.3 4.55 0.67 1.72
1-day 5-year hydrologically based flow 0.00 15.4 1.36 0.00 0.46
1-day 10-year hydrologically based flow 0.00 8.53 0.61 0.00 0.21
3-day 2-year hydrologically based flow 0.63 39.8 5.24 0.77 2.11
3-day 5-year hydrologically based flow 0.00 18.2 1.53 0.00 0.57
3-day 10-year hydrologically based flow 0.00 11.4 0.66 0.00 0.26
7-day 2-year hydrologically based flow 0.63 53.7 7.19 0.87 3.19
7-day 5-year hydrologically based flow 0.03 23.1 2.23 0.03 0.88
7-day 10-year hydrologically based flow 0.00 13.7 1.03 0.00 0.39
14-day 2-year hydrologically based flow 0.79 82.8 11.5 1.11 5.81
14-day 5-year hydrologically based flow 0.06 34.7 3.70 0.08 1.50
14-day 10-year hydrologically based flow 0.01 19.5 1.78 0.01 0.62
30-day 2-year hydrologically based flow 1.95 183 20.0 3.84 18.3
30-day 5-year hydrologically based flow 0.22 80.7 9.23 0.39 3.88
30-day 10-year hydrologically based flow 0.06 44.1 6.34 0.09 1.38
1-day 3-year biologically based flow 0.00 8.20 3.30 0.00 0.00
4-day 3-year biologically based flow 0.00 8.84 4.53 0.00 0.06
EPA harmonic-mean flow 1.32 57.3 42.1 0.41 1.76
5-percent-duration flow 957 1,580 949 291 665
10-percent-duration flow 529 953 571 136 353
15-percent-duration flow 360 706 367 70.7 224
20-percent-duration flow 275 557 273 44.7 158
25-percent-duration flow 208 448 209 31.1 118
30-percent-duration flow 158 378 163 22.5 91.6
35-percent-duration flow 125 326 128 16.6 71.9
40-percent-duration flow 95.8 283 104 12.3 57.8
45-percent-duration flow 72.9 248 83.4 9.1 44.9
50-percent-duration flow 55.5 216 68.2 7.0 34.4
55-percent-duration flow 41.3 190 55.8 5.7 27.2
60-percent-duration flow 30.9 165 45.0 4.5 22.2
65-percent-duration flow 22.7 145 36.8 3.4 18.0
70-percent-duration flow 16.0 126 29.2 2.6 13.6
75-percent-duration flow 10.6 107 22.5 1.8 9.8
80-percent-duration flow 6.9 85.9 16.4 1.1 6.7
85-percent-duration flow 4.3 64.5 11.2 0.5 3.8
90-percent-duration flow 2.1 45.5 7.5 0.2 2.1
95-percent-duration flow 0.6 29.7 4.6 0.0 0.9
99-percent-duration flow 0.0 6.9 0.6 0.0 0.2
Variability index 0.96 0.50 0.70 0.69 0.85
03153500 Little Kanawha River at Grantsville, WV, 1943–1978
1-day 2-year hydrologically based flow 14.7 313 67.7 20.6 37.1
1-day 5-year hydrologically based flow 2.31 174 32.7 3.66 8.48
1-day 10-year hydrologically based flow 0.63 121 21.5 1.04 2.93
3-day 2-year hydrologically based flow 15.0 347 75.4 20.6 40.5
3-day 5-year hydrologically based flow 2.60 187 36.0 4.06 8.99
3-day 10-year hydrologically based flow 0.80 127 23.6 1.32 3.09
7-day 2-year hydrologically based flow 17.3 433 92.2 23.9 49.3
7-day 5-year hydrologically based flow 3.12 221 43.5 4.99 10.6
7-day 10-year hydrologically based flow 1.00 145 28.2 1.75 3.55
14-day 2-year hydrologically based flow 22.8 605 136 31.9 73.7
14-day 5-year hydrologically based flow 4.42 306 60.0 7.48 15.1
14-day 10-year hydrologically based flow 1.52 203 37.5 3.02 4.77
30-day 2-year hydrologically based flow 42.0 1,130 304 65.2 181
30-day 5-year hydrologically based flow 9.09 607 134 17.5 34.0
30-day 10-year hydrologically based flow 3.26 402 82.6 7.67 9.75
1-day 3-year biologically based flow 0.78 79.9 36.9 2.20 1.00
4-day 3-year biologically based flow 0.90 91.1 45.3 2.55 1.66
EPA harmonic-mean flow 16.6 645 393 10.4 7.10
5-percent-duration flow 6,130 9,000 5,610 2,040 4,630
10-percent-duration flow 3,590 6,040 3,440 1,010 2,590
15-percent-duration flow 2,500 4,510 2,430 590 1,760
20-percent-duration flow 1,830 3,550 1,810 406 1,300
25-percent-duration flow 1,450 2,930 1,420 321 999
30-percent-duration flow 1,140 2,480 1,150 247 803
35-percent-duration flow 940 2,100 940 202 650
40-percent-duration flow 750 1,840 777 159 521
45-percent-duration flow 612 1,610 652 134 425
50-percent-duration flow 482 1,430 558 109 337
55-percent-duration flow 391 1,270 477 91.8 277
60-percent-duration flow 305 1,130 412 76.4 220
65-percent-duration flow 239 992 350 62.9 175
70-percent-duration flow 181 872 292 52.4 136
75-percent-duration flow 132 757 238 42.1 101
80-percent-duration flow 94.7 638 193 33.1 72.1
85-percent-duration flow 64.5 514 145 23.7 46.3
90-percent-duration flow 40.3 390 96.4 14.0 22.4
95-percent-duration flow 16.2 278 57.0 5.6 8.5
99-percent-duration flow 1.9 114 25.9 1.2 0.2
Variability index 0.77 0.45 0.59 0.73 0.80
03154000 West Fork Little Kanawha River at Rocksdale, WV, 1955–1975
1-day 2-year hydrologically based flow 0.90 45.9 5.38 1.15 2.68
1-day 5-year hydrologically based flow 0.10 20.8 1.86 0.12 0.64
1-day 10-year hydrologically based flow 0.00 12.7 1.00 0.00 0.23
3-day 2-year hydrologically based flow 1.00 51.3 6.20 1.29 3.30
3-day 5-year hydrologically based flow 0.11 22.4 2.09 0.12 0.76
3-day 10-year hydrologically based flow 0.00 13.4 1.10 0.00 0.25
7-day 2-year hydrologically based flow 1.20 68.3 8.50 1.66 4.89
7-day 5-year hydrologically based flow 0.16 28.4 2.88 0.19 1.44
7-day 10-year hydrologically based flow 0.01 16.3 1.50 0.01 0.60
14-day 2-year hydrologically based flow 1.67 106 13.2 2.44 7.23
14-day 5-year hydrologically based flow 0.24 46.0 4.50 0.28 1.90
14-day 10-year hydrologically based flow 0.01 26.2 2.34 0.01 0.73
30-day 2-year hydrologically based flow 3.52 229 26.0 5.11 21.6
30-day 5-year hydrologically based flow 0.44 103 10.9 0.82 5.78
30-day 10-year hydrologically based flow 0.11 57.7 6.90 0.28 2.58
1-day 3-year biologically based flow 0.00 6.58 4.57 0.00 0.00
4-day 3-year biologically based flow 0.00 11.4 6.00 0.00 0.36
EPA harmonic-mean flow 3.90 72.7 50.2 1.98 2.03
5-percent-duration flow 1,170 1,970 1,150 319 863
10-percent-duration flow 669 1,190 634 148 452
15-percent-duration flow 445 886 434 84.1 293
20-percent-duration flow 328 696 319 53.7 209
25-percent-duration flow 254 567 242 40.4 157
30-percent-duration flow 194 478 188 31.1 121
35-percent-duration flow 154 409 151 24.2 96.1
40-percent-duration flow 120 357 120 19.7 74.5
45-percent-duration flow 91.2 311 96.6 15.7 57.3
50-percent-duration flow 69.6 272 78.4 12.5 44.2
55-percent-duration flow 52.0 237 64.4 9.7 34.5
60-percent-duration flow 38.3 206 53.4 7.3 26.6
65-percent-duration flow 28.7 180 43.6 5.5 20.6
70-percent-duration flow 21.0 156 34.4 3.8 15.8
75-percent-duration flow 14.7 133 26.2 2.7 11.8
80-percent-duration flow 9.7 111 19.8 2.0 8.1
85-percent-duration flow 6.1 87.2 13.5 1.2 5.6
90-percent-duration flow 3.1 62.5 8.5 0.6 3.2
95-percent-duration flow 1.1 36.7 4.7 0.2 1.5
99-percent-duration flow 0.1 8.2 1.0 0.0 0.1
Variability index 0.91 0.50 0.72 0.93 0.83
03154500 Reedy Creek near Reedy, WV, 1953–1978
1-day 2-year hydrologically based flow 0.22 11.3 1.24 0.34 0.64
1-day 5-year hydrologically based flow 0.05 5.17 0.41 0.08 0.13
1-day 10-year hydrologically based flow 0.00 3.23 0.21 0.00 0.05
3-day 2-year hydrologically based flow 0.26 12.0 1.41 0.36 0.73
3-day 5-year hydrologically based flow 0.06 5.48 0.50 0.10 0.17
3-day 10-year hydrologically based flow 0.00 3.46 0.28 0.00 0.07
7-day 2-year hydrologically based flow 0.32 15.6 1.92 0.45 1.09
7-day 5-year hydrologically based flow 0.08 7.19 0.72 0.12 0.26
7-day 10-year hydrologically based flow 0.00 4.64 0.41 0.00 0.10
14-day 2-year hydrologically based flow 0.44 26.7 3.19 0.76 1.61
14-day 5-year hydrologically based flow 0.11 11.5 1.18 0.18 0.37
14-day 10-year hydrologically based flow 0.00 7.03 0.66 0.00 0.15
30-day 2-year hydrologically based flow 0.95 62.6 9.08 2.34 5.32
30-day 5-year hydrologically based flow 0.13 26.3 3.21 0.37 1.12
30-day 10-year hydrologically based flow 0.03 15.1 1.75 0.10 0.44
1-day 3-year biologically based flow 0.00 1.15 0.80 0.00 0.00
4-day 3-year biologically based flow 0.00 1.59 1.07 0.00 0.00
EPA harmonic-mean flow 1.65 22.1 11.4 0.90 0.83
5-percent-duration flow 434 762 428 116 297
10-percent-duration flow 220 433 211 50.3 143
15-percent-duration flow 141 298 137 25.8 92.1
20-percent-duration flow 103 228 98.1 16.8 64.9
25-percent-duration flow 76.6 181 71.7 11.8 48.2
30-percent-duration flow 57.7 148 54.2 8.3 37.1
35-percent-duration flow 43.7 121 42.7 6.2 28.9
40-percent-duration flow 34.0 104 34.7 4.9 22.5
45-percent-duration flow 25.8 90.6 28.3 3.9 17.5
50-percent-duration flow 19.5 79.1 22.9 3.2 13.6
55-percent-duration flow 14.8 68.7 18.2 2.5 9.8
60-percent-duration flow 10.5 58.9 14.9 2.1 7.1
65-percent-duration flow 7.3 50.0 11.6 1.6 5.1
70-percent-duration flow 5.0 42.2 8.8 1.2 3.6
75-percent-duration flow 3.5 34.7 6.5 0.9 2.4
80-percent-duration flow 2.3 26.7 4.6 0.6 1.6
85-percent-duration flow 1.4 20.5 3.3 0.4 1.0
90-percent-duration flow 0.8 15.5 2.0 0.2 0.5
95-percent-duration flow 0.3 8.7 1.0 0.1 0.2
99-percent-duration flow 0.0 2.8 0.3 0.0 0.1
Variability index 0.96 0.57 0.78 0.89 0.95
03155000 Little Kanawha River at Palestine, WV, 1943–1978
1-day 2-year hydrologically based flow 29.2 524 152 38.4 62.8
1-day 5-year hydrologically based flow 7.63 289 65.9 10.7 17.6
1-day 10-year hydrologically based flow 3.30 198 36.7 4.70 8.03
3-day 2-year hydrologically based flow 30.8 563 169 40.8 67.8
3-day 5-year hydrologically based flow 8.05 306 72.3 11.5 18.6
3-day 10-year hydrologically based flow 3.49 211 39.6 5.06 8.37
7-day 2-year hydrologically based flow 34.3 674 203 46.8 76.8
7-day 5-year hydrologically based flow 8.86 351 86.0 12.9 20.4
7-day 10-year hydrologically based flow 3.86 237 47.6 5.71 9.02
14-day 2-year hydrologically based flow 40.8 947 274 62.5 105
14-day 5-year hydrologically based flow 10.7 471 118 17.2 26.8
14-day 10-year hydrologically based flow 4.83 307 68.1 7.79 11.4
30-day 2-year hydrologically based flow 64.5 1,740 524 116 225
30-day 5-year hydrologically based flow 17.0 912 245 36.5 54.4
30-day 10-year hydrologically based flow 7.74 603 154 17.6 21.4
1-day 3-year biologically based flow 1.65 120 74.9 2.40 3.29
4-day 3-year biologically based flow 2.05 151 92.7 3.42 4.76
EPA harmonic-mean flow 93.0 1,030 714 54.8 44.8
5-percent-duration flow 9,000 14,100 8,670 2,790 7,050
10-percent-duration flow 5,740 9,660 5,600 1,480 3,960
15-percent-duration flow 4,010 7,440 3,980 962 2,620
20-percent-duration flow 2,940 6,020 2,960 712 1,930
25-percent-duration flow 2,260 5,020 2,280 545 1,490
30-percent-duration flow 1,790 4,230 1,840 440 1,190
35-percent-duration flow 1,460 3,590 1,520 358 957
40-percent-duration flow 1,170 3,110 1,270 293 805
45-percent-duration flow 955 2,680 1,080 248 666
50-percent-duration flow 786 2,330 919 208 548
55-percent-duration flow 636 2,050 802 175 448
60-percent-duration flow 513 1,810 695 147 355
65-percent-duration flow 406 1,590 606 121 275
70-percent-duration flow 313 1,390 517 100 215
75-percent-duration flow 235 1,200 429 80.5 162
80-percent-duration flow 169 1,010 347 62.8 122
85-percent-duration flow 118 800 273 47.3 77.7
90-percent-duration flow 74.3 621 191 28.2 33.3
95-percent-duration flow 29.3 430 116 11.9 12.6
99-percent-duration flow 4.40 177 53.2 2.7 2.6
Variability index 0.74 0.46 0.56 0.68 0.79
03155500 Hughes River at Cisco, WV, 1940–1989
1-day 2-year hydrologically based flow 3.75 92.0 20.9 4.94 6.67
1-day 5-year hydrologically based flow 1.24 47.0 9.41 1.74 2.06
1-day 10-year hydrologically based flow 0.64 31.7 5.85 0.91 1.08
3-day 2-year hydrologically based flow 4.06 99.9 23.6 5.41 7.29
3-day 5-year hydrologically based flow 1.31 49.8 10.3 1.87 2.20
3-day 10-year hydrologically based flow 0.66 33.3 6.31 0.97 1.13
7-day 2-year hydrologically based flow 4.66 122 30.0 6.51 8.72
7-day 5-year hydrologically based flow 1.45 59.0 12.7 2.19 2.57
7-day 10-year hydrologically based flow 0.73 39.0 7.73 1.12 1.29
14-day 2-year hydrologically based flow 5.83 176 45.1 8.57 11.8
14-day 5-year hydrologically based flow 1.83 80.7 18.6 2.84 3.44
14-day 10-year hydrologically based flow 0.94 51.7 11.4 1.48 1.69
30-day 2-year hydrologically based flow 9.45 419 105 18.9 39.6
30-day 5-year hydrologically based flow 2.97 208 44.5 6.41 10.5
30-day 10-year hydrologically based flow 1.55 133 27.5 3.41 4.75
1-day 3-year biologically based flow 0.37 19.0 15.0 0.89 0.43
4-day 3-year biologically based flow 0.48 23.0 19.4 1.33 0.77
EPA harmonic-mean flow 18.5 208 151 10.9 8.87
5-percent-duration flow 2,620 3,940 2,670 777 1,980
10-percent-duration flow 1,480 2,570 1,570 354 1,010
15-percent-duration flow 976 1,920 1,030 223 674
20-percent-duration flow 707 1,440 758 156 487
25-percent-duration flow 546 1,130 597 114 365
30-percent-duration flow 434 930 483 87.1 281
35-percent-duration flow 341 787 392 69.1 224
40-percent-duration flow 275 677 323 54.9 178
45-percent-duration flow 220 588 274 43.8 139
50-percent-duration flow 174 517 232 35.9 107
55-percent-duration flow 137 451 197 29.1 80.8
60-percent-duration flow 104 395 163 24.2 59.1
65-percent-duration flow 77.4 345 135 19.8 43.3
70-percent-duration flow 55.6 298 111 16.2 31.7
75-percent-duration flow 38.6 252 88.7 12.8 24.3
80-percent-duration flow 27.3 208 69.4 9.6 17.8
85-percent-duration flow 19.0 164 48.1 7.0 11.7
90-percent-duration flow 11.6 119 32.3 4.4 6.4
95-percent-duration flow 4.9 75.2 20.2 2.4 2.4
99-percent-duration flow 1.1 29.1 6.9 0.8 0.6
Variability index 0.82 0.51 0.63 0.74 0.87
03179000 Bluestone River near Pipestem, WV, 1952–1978
1-day 2-year hydrologically based flow 21.6 131 72.4 23.1 31.7
1-day 5-year hydrologically based flow 14.0 63.8 47.6 14.7 17.7
1-day 10-year hydrologically based flow 11.1 40.5 37.5 11.5 13.5
3-day 2-year hydrologically based flow 22.4 144 80.3 24.5 32.9
3-day 5-year hydrologically based flow 14.6 69.3 51.9 15.5 18.3
3-day 10-year hydrologically based flow 11.6 44.0 40.4 12.1 14.0
7-day 2-year hydrologically based flow 24.1 183 95.0 26.8 36.5
7-day 5-year hydrologically based flow 15.7 84.5 61.4 16.9 19.5
7-day 10-year hydrologically based flow 12.6 51.2 48.0 13.2 14.7
14-day 2-year hydrologically based flow 26.9 243 118 32.5 42.8
14-day 5-year hydrologically based flow 17.4 108 74.3 20.4 22.1
14-day 10-year hydrologically based flow 14.0 63.8 58.9 15.8 16.4
30-day 2-year hydrologically based flow 35.6 389 179 43.9 68.8
30-day 5-year hydrologically based flow 22.7 188 108 29.1 30.2
30-day 10-year hydrologically based flow 17.9 116 84.0 23.3 19.9
1-day 3-year biologically based flow 12.0 24.9 63.9 13.0 12.0
4-day 3-year biologically based flow 12.5 28.0 75.2 17.1 13.1
EPA harmonic-mean flow 90.3 222 304 59.1 51.3
5-percent-duration flow 1,790 3,080 1,870 327 1,300
10-percent-duration flow 1,110 1,960 1,210 211 784
15-percent-duration flow 824 1,490 889 163 556
20-percent-duration flow 652 1,210 738 133 420
25-percent-duration flow 531 1,010 625 114 326
30-percent-duration flow 438 880 535 99.9 253
35-percent-duration flow 365 779 470 88.3 203
40-percent-duration flow 299 684 412 79.2 169
45-percent-duration flow 244 608 361 71.4 136
50-percent-duration flow 198 555 318 64.3 112
55-percent-duration flow 160 501 281 58.0 95.0
60-percent-duration flow 130 448 248 51.9 80.7
65-percent-duration flow 106 400 217 47.1 67.2
70-percent-duration flow 87.6 356 185 42.2 55.4
75-percent-duration flow 70.8 304 160 37.2 45.1
80-percent-duration flow 56.5 253 137 32.6 37.3
85-percent-duration flow 43.9 205 116 28.4 31.1
90-percent-duration flow 33.4 152 96.7 24.3 26.4
95-percent-duration flow 24.7 92.2 73.0 19.4 18.9
99-percent-duration flow 15.2 26.5 43.9 13.2 14.3
Variability index 0.59 0.44 0.42 0.37 0.58
03180500 Greenbrier River at Durbin, WV, 1944–2002
1-day 2-year hydrologically based flow 7.76 69.5 31.4 8.40 16.5
1-day 5-year hydrologically based flow 3.07 45.8 18.8 3.37 6.38
1-day 10-year hydrologically based flow 1.71 36.4 14.0 1.90 3.59
3-day 2-year hydrologically based flow 8.33 75.0 34.8 9.13 17.7
3-day 5-year hydrologically based flow 3.37 48.7 20.7 3.72 6.90
3-day 10-year hydrologically based flow 1.91 38.5 15.4 2.11 3.92
7-day 2-year hydrologically based flow 9.57 86.0 42.1 10.7 20.1
7-day 5-year hydrologically based flow 3.94 54.9 25.3 4.36 8.30
7-day 10-year hydrologically based flow 2.27 42.9 19.2 2.49 5.08
14-day 2-year hydrologically based flow 11.7 113 56.8 13.9 24.4
14-day 5-year hydrologically based flow 4.80 68.2 34.0 5.57 9.91
14-day 10-year hydrologically based flow 2.82 52.1 25.6 3.18 6.05
30-day 2-year hydrologically based flow 16.2 202 108 21.0 45.4
30-day 5-year hydrologically based flow 7.36 121 63.4 9.29 17.2
30-day 10-year hydrologically based flow 4.67 88.7 45.9 5.93 9.91
1-day 3-year biologically based flow 1.58 30.0 28.0 1.64 1.96
4-day 3-year biologically based flow 1.79 36.2 35.7 2.09 3.78
EPA harmonic-mean flow 36.4 166 180 20.5 20.3
5-percent-duration flow 955 1,450 953 310 757
10-percent-duration flow 615 966 653 183 480
15-percent-duration flow 472 756 509 131 362
20-percent-duration flow 381 622 419 101 287
25-percent-duration flow 311 531 357 80.3 240
30-percent-duration flow 264 464 310 65.5 200
35-percent-duration flow 222 415 276 54.8 173
40-percent-duration flow 191 370 244 46.7 148
45-percent-duration flow 162 329 215 40.0 127
50-percent-duration flow 138 295 192 34.7 106
55-percent-duration flow 114 264 170 29.7 86.6
60-percent-duration flow 92.6 235 150 25.7 70.9
65-percent-duration flow 74.8 210 131 22.0 57.3
70-percent-duration flow 59.2 185 113 18.9 45.5
75-percent-duration flow 45.8 161 97.5 16.0 36.2
80-percent-duration flow 34.3 140 80.4 13.5 27.7
85-percent-duration flow 24.8 118 64.3 10.4 18.9
90-percent-duration flow 16.5 92.6 49.0 7.5 13.3
95-percent-duration flow 9.9 67.8 33.6 4.9 8.9
99-percent-duration flow 3.5 38.3 17.5 1.6 4.3
Variability index 0.60 0.39 0.43 0.53 0.59
03182000 Knapp Creek at Marlinton, WV, 1947–1958
1-day 2-year hydrologically based flow 8.94 40.3 20.4 9.28 11.2
1-day 5-year hydrologically based flow 5.32 22.7 16.2 5.35 7.78
1-day 10-year hydrologically based flow 3.77 15.4 14.3 3.75 6.59
3-day 2-year hydrologically based flow 9.36 44.7 22.0 9.81 11.5
3-day 5-year hydrologically based flow 5.48 25.3 17.5 5.55 7.92
3-day 10-year hydrologically based flow 3.85 17.0 15.4 3.84 6.71
7-day 2-year hydrologically based flow 10.0 53.3 25.5 10.5 12.5
7-day 5-year hydrologically based flow 5.81 28.1 19.7 5.91 8.39
7-day 10-year hydrologically based flow 4.10 18.5 17.3 4.11 6.90
14-day 2-year hydrologically based flow 11.5 74.6 33.1 12.0 15.8
14-day 5-year hydrologically based flow 6.51 36.1 25.0 6.63 10.1
14-day 10-year hydrologically based flow 4.59 22.2 21.8 4.61 7.88
30-day 2-year hydrologically based flow 13.2 114 55.9 14.3 24.0
30-day 5-year hydrologically based flow 8.11 58.4 41.3 8.49 12.2
30-day 10-year hydrologically based flow 6.40 37.2 35.9 6.52 8.45
1-day 3-year biologically based flow 2.14 8.40 20.0 2.08 3.38
4-day 3-year biologically based flow 3.62 9.05 22.7 5.56 6.99
EPA harmonic-mean flow 30.6 82.0 85.1 17.7 20.1
5-percent-duration flow 579 895 507 126 455
10-percent-duration flow 344 594 336 72.1 239
15-percent-duration flow 251 469 247 52.1 175
20-percent-duration flow 195 374 198 42.2 134
25-percent-duration flow 160 314 166 35.7 102
30-percent-duration flow 133 275 143 30.2 82.8
35-percent-duration flow 109 242 124 26.3 69.3
40-percent-duration flow 90.4 209 110 23.3 57.7
45-percent-duration flow 74.8 189 97.3 21.3 46.6
50-percent-duration flow 62.9 170 87.3 19.4 39.5
55-percent-duration flow 52.9 154 79.5 17.5 31.7
60-percent-duration flow 44.0 139 71.2 15.9 26.7
65-percent-duration flow 34.4 126 63.8 14.5 22.2
70-percent-duration flow 27.5 110 57.4 13.3 18.8
75-percent-duration flow 22.2 93.1 51.4 12.2 16.0
80-percent-duration flow 17.9 78.8 45.2 11.0 13.7
85-percent-duration flow 14.5 65.4 37.6 9.8 12.3
90-percent-duration flow 11.9 50.2 30.0 8.5 10.7
95-percent-duration flow 9.0 35.1 24.1 7.1 8.5
99-percent-duration flow 6.4 9.5 17.4 3.0 7.1
Variability index 0.57 0.41 0.39 0.37 0.55
03182500 Greenbrier River at Buckeye, WV, 1931–2002
1-day 2-year hydrologically based flow 29.7 234 108 32.4 49.2
1-day 5-year hydrologically based flow 17.0 143 68.5 18.0 26.4
1-day 10-year hydrologically based flow 12.6 107 53.1 12.9 19.2
3-day 2-year hydrologically based flow 30.7 254 120 33.8 51.7
3-day 5-year hydrologically based flow 17.9 155 75.5 18.9 27.5
3-day 10-year hydrologically based flow 13.3 116 58.2 13.8 20.0
7-day 2-year hydrologically based flow 33.4 299 143 37.7 58.6
7-day 5-year hydrologically based flow 19.3 178 89.9 21.0 30.2
7-day 10-year hydrologically based flow 14.5 132 69.2 15.3 21.7
14-day 2-year hydrologically based flow 38.4 392 192 45.7 69.9
14-day 5-year hydrologically based flow 21.7 220 116 24.5 34.4
14-day 10-year hydrologically based flow 16.3 159 88.0 17.7 24.1
30-day 2-year hydrologically based flow 50.8 696 341 68.3 129
30-day 5-year hydrologically based flow 28.4 389 196 34.7 53.8
30-day 10-year hydrologically based flow 21.4 272 141 24.9 33.9
1-day 3-year biologically based flow 11.0 82.0 91.9 11.9 11.9
4-day 3-year biologically based flow 15.4 115 112 17.1 17.4
EPA harmonic-mean flow 144 521 540 82.1 84.7
5-percent-duration flow 3,310 5,020 3,250 1,020 2,580
10-percent-duration flow 2,100 3,440 2,160 588 1,520
15-percent-duration flow 1,550 2,640 1,660 406 1,100
20-percent-duration flow 1,240 2,170 1,350 310 855
25-percent-duration flow 1,010 1,840 1,150 252 684
30-percent-duration flow 836 1,610 993 209 571
35-percent-duration flow 689 1,420 860 176 481
40-percent-duration flow 586 1,250 748 149 406
45-percent-duration flow 492 1,110 653 129 336
50-percent-duration flow 414 990 576 112 277
55-percent-duration flow 341 877 515 96.8 227
60-percent-duration flow 277 781 458 84.9 183
65-percent-duration flow 223 691 401 73.5 149
70-percent-duration flow 175 605 348 63.0 119
75-percent-duration flow 136 524 299 53.3 95.1
80-percent-duration flow 103 453 251 44.6 75.0
85-percent-duration flow 76.7 371 201 37.3 58.5
90-percent-duration flow 53.8 296 155 30.2 43.6
95-percent-duration flow 34.7 207 112 21.8 31.7
99-percent-duration flow 16.9 101 60.1 12.1 16.8
Variability index 0.61 0.41 0.44 0.50 0.59
03183000 Second Creek near Second Creek, WV, 1948–1964
1-day 2-year hydrologically based flow 4.18 20.7 12.1 4.51 5.36
1-day 5-year hydrologically based flow 3.04 9.25 8.26 3.40 3.46
1-day 10-year hydrologically based flow 2.58 5.65 6.77 2.98 2.73
3-day 2-year hydrologically based flow 4.71 23.9 13.2 5.01 6.06
3-day 5-year hydrologically based flow 3.58 11.1 9.03 3.83 4.07
3-day 10-year hydrologically based flow 3.15 6.95 7.37 3.37 3.31
7-day 2-year hydrologically based flow 5.22 29.6 15.4 5.51 6.76
7-day 5-year hydrologically based flow 3.99 14.0 10.7 4.19 4.65
7-day 10-year hydrologically based flow 3.51 8.92 8.86 3.67 3.82
14-day 2-year hydrologically based flow 5.72 43.1 19.6 6.07 7.61
14-day 5-year hydrologically based flow 4.29 19.6 13.6 4.51 5.01
14-day 10-year hydrologically based flow 3.74 12.0 11.2 3.97 4.08
30-day 2-year hydrologically based flow 6.58 64.5 28.5 7.28 11.1
30-day 5-year hydrologically based flow 4.87 33.7 19.5 5.69 5.94
30-day 10-year hydrologically based flow 4.19 22.5 15.7 5.14 4.33
1-day 3-year biologically based flow 2.68 4.09 10.9 3.39 2.66
4-day 3-year biologically based flow 3.22 4.95 12.2 4.26 3.23
EPA harmonic-mean flow 16.4 37.8 48.9 10.4 10.0
5-percent-duration flow 297 548 292 55.4 200
10-percent-duration flow 183 332 193 32.7 106
15-percent-duration flow 135 246 143 24.6 72.6
20-percent-duration flow 106 201 114 20.5 54.6
25-percent-duration flow 86.7 175 97.1 17.6 44.6
30-percent-duration flow 70.4 154 84.4 15.4 36.3
35-percent-duration flow 57.6 136 73.1 13.8 29.0
40-percent-duration flow 47.4 123 63.9 12.4 23.5
45-percent-duration flow 39.0 110 56.6 11.2 19.6
50-percent-duration flow 31.7 99.2 50.4 9.9 16.6
55-percent-duration flow 25.5 88.3 45.3 9.1 14.1
60-percent-duration flow 20.3 79.8 40.5 8.4 12.2
65-percent-duration flow 16.7 71.3 35.8 7.7 10.2
70-percent-duration flow 13.7 63.2 31.3 7.1 8.6
75-percent-duration flow 11.4 54.9 27.4 6.7 7.7
80-percent-duration flow 8.9 46.4 23.2 6.2 6.8
85-percent-duration flow 7.5 37.6 19.8 5.8 6.0
90-percent-duration flow 6.3 27.9 16.3 5.2 5.3
95-percent-duration flow 5.1 16.4 12.5 4.5 4.4
99-percent-duration flow 3.6 5.5 8.6 3.4 3.2
Variability index 0.57 0.43 0.41 0.33 0.52
03183500 Greenbrier River at Alderson, WV, 1930–2002
1-day 2-year hydrologically based flow 84.1 540 281 92.8 126
1-day 5-year hydrologically based flow 54.9 313 180 58.5 74.8
1-day 10-year hydrologically based flow 44.0 224 142 45.8 57.6
3-day 2-year hydrologically based flow 86.7 577 302 96.2 130
3-day 5-year hydrologically based flow 57.0 336 193 61.1 76.5
3-day 10-year hydrologically based flow 46.0 241 152 48.2 59.2
7-day 2-year hydrologically based flow 91.1 683 346 103 140
7-day 5-year hydrologically based flow 59.3 384 218 64.8 80.1
7-day 10-year hydrologically based flow 48.0 272 171 50.9 61.4
14-day 2-year hydrologically based flow 101 879 446 120 163
14-day 5-year hydrologically based flow 64.4 465 277 73.2 88.2
14-day 10-year hydrologically based flow 52.1 321 216 56.9 65.5
30-day 2-year hydrologically based flow 125 1,560 756 167 272
30-day 5-year hydrologically based flow 77.5 836 447 94.1 124
30-day 10-year hydrologically based flow 62.0 568 334 72.3 82.6
1-day 3-year biologically based flow 45.0 140 244 46.9 47.9
4-day 3-year biologically based flow 47.9 185 268 51.5 57.9
EPA harmonic-mean flow 367 1,090 1,250 224 213
5-percent-duration flow 7,110 11,400 7,090 2,190 5,340
10-percent-duration flow 4,600 7,620 4,770 1,250 3,140
15-percent-duration flow 3,420 6,020 3,660 872 2,290
20-percent-duration flow 2,700 4,950 2,980 680 1,800
25-percent-duration flow 2,190 4,170 2,530 555 1,460
30-percent-duration flow 1,840 3,600 2,190 466 1,200
35-percent-duration flow 1,540 3,170 1,910 401 978
40-percent-duration flow 1,290 2,810 1,680 347 795
45-percent-duration flow 1,080 2,490 1,490 301 668
50-percent-duration flow 895 2,230 1,320 264 549
55-percent-duration flow 739 1,980 1,170 233 444
60-percent-duration flow 603 1,770 1,040 206 359
65-percent-duration flow 483 1,560 918 183 293
70-percent-duration flow 382 1,370 804 161 241
75-percent-duration flow 301 1,180 692 141 198
80-percent-duration flow 235 989 588 121 165
85-percent-duration flow 182 821 479 102 132
90-percent-duration flow 135 654 376 84.1 106
95-percent-duration flow 92.6 444 274 66.3 81.1
99-percent-duration flow 54.7 193 161 44.2 50.1
Variability index 0.59 0.42 0.42 0.45 0.57
03184000 Greenbrier River at Hilldale, WV, 1938–2002
1-day 2-year hydrologically based flow 91.1 622 329 101 132
1-day 5-year hydrologically based flow 59.6 349 210 64.3 78.1
1-day 10-year hydrologically based flow 48.2 245 165 50.8 61.4
3-day 2-year hydrologically based flow 93.4 667 352 105 137
3-day 5-year hydrologically based flow 60.7 375 223 66.1 80.1
3-day 10-year hydrologically based flow 49.0 262 175 52.0 62.8
7-day 2-year hydrologically based flow 97.9 796 400 113 148
7-day 5-year hydrologically based flow 63.4 437 252 70.6 83.6
7-day 10-year hydrologically based flow 51.5 303 197 55.6 64.6
14-day 2-year hydrologically based flow 108 1,050 518 132 171
14-day 5-year hydrologically based flow 68.2 528 319 79.5 91.0
14-day 10-year hydrologically based flow 55.2 354 246 61.9 68.0
30-day 2-year hydrologically based flow 136 1,870 913 186 288
30-day 5-year hydrologically based flow 82.6 995 530 106 128
30-day 10-year hydrologically based flow 65.9 670 391 80.7 85.7
1-day 3-year biologically based flow 45.9 170 293 49.9 48.0
4-day 3-year biologically based flow 49.9 203 337 57.8 58.3
EPA harmonic-mean flow 413 1,250 1,530 261 229
5-percent-duration flow 8,300 13,200 8,560 2,460 6,110
10-percent-duration flow 5,510 8,720 5,670 1,420 3,750
15-percent-duration flow 4,140 7,030 4,440 1,000 2,740
20-percent-duration flow 3,270 5,920 3,600 774 2,100
25-percent-duration flow 2,670 5,050 3,030 629 1,680
30-percent-duration flow 2,220 4,400 2,610 525 1,380
35-percent-duration flow 1,840 3,890 2,280 451 1,110
40-percent-duration flow 1,530 3,460 2,020 390 908
45-percent-duration flow 1,270 3,090 1,790 339 753
50-percent-duration flow 1,050 2,760 1,590 299 625
55-percent-duration flow 864 2,450 1,420 265 507
60-percent-duration flow 696 2,170 1,250 234 406
65-percent-duration flow 555 1,910 1,100 207 329
70-percent-duration flow 434 1,670 962 182 265
75-percent-duration flow 342 1,430 831 159 216
80-percent-duration flow 265 1,180 700 136 178
85-percent-duration flow 202 981 563 114 142
90-percent-duration flow 148 764 437 93.6 108
95-percent-duration flow 99.1 496 324 73.7 84.7
99-percent-duration flow 61.7 205 177 51.3 56.8
Variability index 0.60 0.42 0.43 0.46 0.59
03185000 Piney Creek at Raleigh, WV, 1953–1978
1-day 2-year hydrologically based flow 1.85 19.3 9.95 2.40 2.69
1-day 5-year hydrologically based flow 0.86 7.91 5.39 1.12 1.16
1-day 10-year hydrologically based flow 0.56 4.22 3.55 0.70 0.78
3-day 2-year hydrologically based flow 1.99 20.9 11.3 2.58 2.96
3-day 5-year hydrologically based flow 0.93 8.47 6.16 1.19 1.31
3-day 10-year hydrologically based flow 0.61 4.48 4.04 0.74 0.90
7-day 2-year hydrologically based flow 2.19 26.3 13.7 2.99 3.30
7-day 5-year hydrologically based flow 1.00 10.4 7.74 1.36 1.43
7-day 10-year hydrologically based flow 0.64 5.28 5.26 0.82 0.96
14-day 2-year hydrologically based flow 2.60 34.7 17.0 3.85 3.77
14-day 5-year hydrologically based flow 1.16 13.6 9.77 1.71 1.61
14-day 10-year hydrologically based flow 0.73 6.68 6.91 1.00 1.09
30-day 2-year hydrologically based flow 3.74 55.8 26.0 6.30 7.28
30-day 5-year hydrologically based flow 1.73 26.1 14.5 2.91 2.76
30-day 10-year hydrologically based flow 1.10 14.7 10.3 1.71 1.64
1-day 3-year biologically based flow 0.54 3.08 6.88 0.77 0.66
4-day 3-year biologically based flow 0.63 3.88 8.43 0.87 0.80
EPA harmonic-mean flow 8.41 19.5 39.7 5.80 4.43
5-percent-duration flow 217 384 210 66.4 157
10-percent-duration flow 143 244 148 39.4 103
15-percent-duration flow 110 182 116 28.0 75.9
20-percent-duration flow 88.2 149 95.5 22.9 57.8
25-percent-duration flow 71.7 129 82.0 18.9 45.9
30-percent-duration flow 60.3 114 71.0 16.0 36.7
35-percent-duration flow 50.5 101 62.5 13.6 30.0
40-percent-duration flow 41.9 90.8 54.9 11.7 25.0
45-percent-duration flow 35.2 81.6 48.0 10.0 19.6
50-percent-duration flow 29.2 73.3 42.6 8.5 14.8
55-percent-duration flow 24.2 66.2 37.5 7.7 11.4
60-percent-duration flow 19.4 59.2 33.3 6.8 8.9
65-percent-duration flow 15.4 53.1 29.5 6.2 7.3
70-percent-duration flow 11.9 47.0 26.3 5.5 5.9
75-percent-duration flow 8.9 41.5 23.2 4.7 4.8
80-percent-duration flow 6.9 35.9 20.1 4.0 3.9
85-percent-duration flow 5.3 30.4 16.4 3.2 3.0
90-percent-duration flow 3.7 20.7 13.3 2.4 2.2
95-percent-duration flow 2.2 13.2 9.1 1.5 1.3
99-percent-duration flow 0.8 1.7 4.9 0.4 0.8
Variability index 0.62 0.41 0.41 0.48 0.65
03186500 Williams River at Dyer, WV, 1931–2002
1-day 2-year hydrologically based flow 7.15 94.3 30.9 7.78 18.1
1-day 5-year hydrologically based flow 2.91 64.8 16.2 3.18 6.72
1-day 10-year hydrologically based flow 1.77 51.6 11.2 1.95 3.81
3-day 2-year hydrologically based flow 7.69 102 35.3 8.52 19.5
3-day 5-year hydrologically based flow 3.13 70.0 18.3 3.47 7.15
3-day 10-year hydrologically based flow 1.91 55.6 12.5 2.13 4.02
7-day 2-year hydrologically based flow 9.04 117 46.4 10.5 24.8
7-day 5-year hydrologically based flow 3.63 78.0 23.5 4.18 8.84
7-day 10-year hydrologically based flow 2.21 61.9 15.8 2.54 4.81
14-day 2-year hydrologically based flow 11.9 150 67.6 14.9 33.7
14-day 5-year hydrologically based flow 4.71 93.6 34.5 5.78 11.6
14-day 10-year hydrologically based flow 2.81 73.1 23.4 3.42 6.18
30-day 2-year hydrologically based flow 20.1 258 128 31.6 77.2
30-day 5-year hydrologically based flow 8.12 164 67.2 11.8 25.1
30-day 10-year hydrologically based flow 5.00 126 45.4 6.81 12.5
1-day 3-year biologically based flow 1.56 42.8 19.0 1.99 2.20
4-day 3-year biologically based flow 2.02 56.0 26.1 2.65 2.80
EPA harmonic-mean flow 41.2 222 175 23.5 22.6
5-percent-duration flow 1,190 1,740 1,090 580 1,020
10-percent-duration flow 776 1,180 776 340 656
15-percent-duration flow 588 910 614 244 491
20-percent-duration flow 478 750 510 184 388
25-percent-duration flow 401 641 434 142 327
30-percent-duration flow 335 557 374 114 277
35-percent-duration flow 290 494 330 93.3 235
40-percent-duration flow 246 440 289 77.6 205
45-percent-duration flow 212 392 254 64.1 178
50-percent-duration flow 180 354 224 53.5 154
55-percent-duration flow 153 317 196 44.4 131
60-percent-duration flow 129 282 173 36.5 113
65-percent-duration flow 107 250 150 30.0 96.4
70-percent-duration flow 87.1 220 129 24.3 79.4
75-percent-duration flow 68.2 192 108 19.3 61.2
80-percent-duration flow 49.7 165 88.5 15.0 42.7
85-percent-duration flow 32.8 139 69.9 10.7 26.7
90-percent-duration flow 19.8 118 51.1 7.1 15.9
95-percent-duration flow 9.5 91.9 32.1 4.3 8.8
99-percent-duration flow 3.1 59.3 12.1 2.1 2.9
Variability index 0.62 0.39 0.46 0.64 0.61
03187000 Gauley River at Camden On Gauley, WV, 1932–1957
1-day 2-year hydrologically based flow 16.4 173 63.5 16.7 25.9
1-day 5-year hydrologically based flow 5.30 112 37.8 6.74 7.85
1-day 10-year hydrologically based flow 2.57 87.1 28.7 4.04 3.57
3-day 2-year hydrologically based flow 17.6 196 72.7 18.3 28.4
3-day 5-year hydrologically based flow 5.56 127 43.1 7.25 8.53
3-day 10-year hydrologically based flow 2.66 97.6 32.5 4.28 3.80
7-day 2-year hydrologically based flow 20.4 226 94.2 22.6 35.9
7-day 5-year hydrologically based flow 6.31 140 56.0 8.80 10.3
7-day 10-year hydrologically based flow 3.01 105 41.9 5.12 4.44
14-day 2-year hydrologically based flow 26.7 302 140 33.2 45.7
14-day 5-year hydrologically based flow 8.21 173 78.1 12.6 12.8
14-day 10-year hydrologically based flow 3.92 125 56.3 7.13 5.50
30-day 2-year hydrologically based flow 39.1 519 235 67.8 98.5
30-day 5-year hydrologically based flow 12.6 324 136 24.9 27.3
30-day 10-year hydrologically based flow 6.30 241 98.7 13.7 11.9
1-day 3-year biologically based flow 3.45 80.0 29.9 4.18 4.35
4-day 3-year biologically based flow 4.15 95.8 50.7 5.39 4.95
EPA harmonic-mean flow 57.8 430 292 49.7 23.1
5-percent-duration flow 2,040 3,070 1,820 1,100 1,510
10-percent-duration flow 1,370 2,140 1,290 668 958
15-percent-duration flow 1,050 1,650 1,020 483 720
20-percent-duration flow 859 1,400 859 367 595
25-percent-duration flow 724 1,210 742 291 488
30-percent-duration flow 607 1,060 642 236 405
35-percent-duration flow 523 960 560 192 348
40-percent-duration flow 446 869 497 159 302
45-percent-duration flow 383 789 443 132 259
50-percent-duration flow 326 714 394 109 219
55-percent-duration flow 275 643 352 91.0 187
60-percent-duration flow 229 579 311 75.4 160
65-percent-duration flow 189 521 272 61.4 133
70-percent-duration flow 151 468 238 49.2 105
75-percent-duration flow 117 411 199 39.6 73.8
80-percent-duration flow 86.5 351 163 30.4 47.6
85-percent-duration flow 57.1 293 133 22.1 31.4
90-percent-duration flow 35.2 233 100 15.1 21.0
95-percent-duration flow 17.9 169 70.6 9.5 12.2
99-percent-duration flow 5.4 68.6 35.0 3.8 1.4
Variability index 0.62 0.37 0.42 0.63 0.63
03187500 Cranberry River near Richwood, WV, 1966–1979
1-day 2-year hydrologically based flow 6.44 68.0 22.2 6.82 27.8
1-day 5-year hydrologically based flow 3.82 44.6 10.1 3.89 12.7
1-day 10-year hydrologically based flow 2.86 35.7 5.96 2.87 7.82
3-day 2-year hydrologically based flow 7.13 70.8 25.9 7.65 31.1
3-day 5-year hydrologically based flow 4.13 45.7 11.4 4.21 13.9
3-day 10-year hydrologically based flow 3.03 36.1 6.64 3.03 8.48
7-day 2-year hydrologically based flow 8.64 77.4 30.8 9.58 38.3
7-day 5-year hydrologically based flow 4.86 47.0 13.0 5.49 18.0
7-day 10-year hydrologically based flow 3.47 36.4 7.69 4.14 11.7
14-day 2-year hydrologically based flow 12.1 93.2 41.5 14.3 48.9
14-day 5-year hydrologically based flow 6.66 52.7 17.9 8.06 22.0
14-day 10-year hydrologically based flow 4.72 39.1 11.1 6.02 13.8
30-day 2-year hydrologically based flow 21.0 150 75.7 26.7 113
30-day 5-year hydrologically based flow 12.6 74.8 35.9 17.2 59.8
30-day 10-year hydrologically based flow 9.25 49.7 23.2 14.0 37.1
1-day 3-year biologically based flow 2.07 32.0 14.9 2.09 4.49
4-day 3-year biologically based flow 3.31 34.9 16.6 3.31 5.26
EPA harmonic-mean flow 52.4 139 124 26.1 44.2
5-percent-duration flow 818 1,140 775 409 783
10-percent-duration flow 564 803 568 258 541
15-percent-duration flow 433 635 460 191 411
20-percent-duration flow 359 514 383 150 342
25-percent-duration flow 303 437 325 122 282
30-percent-duration flow 257 384 285 98.2 246
35-percent-duration flow 221 343 250 81.0 215
40-percent-duration flow 189 309 218 67.8 188
45-percent-duration flow 161 279 188 57.7 167
50-percent-duration flow 140 249 163 49.6 149
55-percent-duration flow 120 216 140 42.6 135
60-percent-duration flow 101 191 119 36.6 120
65-percent-duration flow 83.7 167 100 31.2 105
70-percent-duration flow 68.7 142 83.5 26.0 88.8
75-percent-duration flow 56.0 118 69.1 21.3 76.0
80-percent-duration flow 45.0 97.0 56.9 17.4 65.0
85-percent-duration flow 34.6 78.1 44.2 13.7 53.0
90-percent-duration flow 23.6 56.6 31.9 9.7 37.1
95-percent-duration flow 12.9 43.5 19.5 6.8 19.1
99-percent-duration flow 5.5 34.3 6.5 3.8 8.1
Variability index 0.54 0.43 0.49 0.54 0.46
03189000 Cherry River at Fenwick, WV, 1932–1957
1-day 2-year hydrologically based flow 4.44 107 29.8 5.56 8.03
1-day 5-year hydrologically based flow 1.49 67.8 14.1 2.13 2.22
1-day 10-year hydrologically based flow 0.82 52.0 9.34 1.27 1.12
3-day 2-year hydrologically based flow 5.32 124 37.1 6.32 8.77
3-day 5-year hydrologically based flow 2.03 75.9 18.0 2.48 2.86
3-day 10-year hydrologically based flow 1.23 56.4 12.1 1.50 1.64
7-day 2-year hydrologically based flow 6.55 154 55.0 8.22 12.0
7-day 5-year hydrologically based flow 2.46 87.1 26.4 3.29 3.74
7-day 10-year hydrologically based flow 1.48 62.0 17.0 2.03 2.01
14-day 2-year hydrologically based flow 8.71 200 95.2 11.9 19.8
14-day 5-year hydrologically based flow 3.20 113 43.5 4.59 5.53
14-day 10-year hydrologically based flow 1.87 82.1 26.1 2.71 2.72
30-day 2-year hydrologically based flow 14.6 358 161 29.9 46.1
30-day 5-year hydrologically based flow 5.02 209 76.4 10.5 12.1
30-day 10-year hydrologically based flow 2.82 152 47.1 5.67 5.62
1-day 3-year biologically based flow 1.00 44.9 11.0 1.48 1.18
4-day 3-year biologically based flow 1.18 54.8 19.2 2.10 1.42
EPA harmonic-mean flow 29.3 286 166 19.7 13.1
5-percent-duration flow 1,450 2,280 1,380 757 1,130
10-percent-duration flow 1,020 1,590 970 448 740
15-percent-duration flow 779 1,230 787 312 556
20-percent-duration flow 648 1,060 664 224 438
25-percent-duration flow 535 900 566 164 351
30-percent-duration flow 451 808 488 125 291
35-percent-duration flow 379 724 425 98.3 245
40-percent-duration flow 317 650 373 78.0 209
45-percent-duration flow 267 591 326 62.0 177
50-percent-duration flow 221 534 288 49.4 147
55-percent-duration flow 181 479 254 40.6 119
60-percent-duration flow 146 428 224 33.1 95.7
65-percent-duration flow 114 381 195 26.8 74.0
70-percent-duration flow 86.1 341 166 21.1 53.8
75-percent-duration flow 62.1 297 139 16.0 35.7
80-percent-duration flow 41.2 241 109 12.3 19.6
85-percent-duration flow 25.5 188 80.7 8.5 12.7
90-percent-duration flow 14.0 144 56.6 5.6 8.4
95-percent-duration flow 6.6 102 34.4 3.4 4.5
99-percent-duration flow 2.0 52.9 12.6 1.6 0.7
Variability index 0.71 0.40 0.48 0.72 0.75
03189100 Gauley River near Craigsville, WV, 1966–1979
1-day 2-year hydrologically based flow 45.4 433 141 50.8 153
1-day 5-year hydrologically based flow 26.4 334 74.4 27.9 69.6
1-day 10-year hydrologically based flow 19.5 295 49.9 19.9 43.5
3-day 2-year hydrologically based flow 48.9 457 159 55.1 168
3-day 5-year hydrologically based flow 29.1 345 83.8 30.4 73.6
3-day 10-year hydrologically based flow 21.7 299 56.3 21.9 45.8
7-day 2-year hydrologically based flow 57.2 510 182 68.4 197
7-day 5-year hydrologically based flow 33.3 353 91.9 36.6 90.5
7-day 10-year hydrologically based flow 24.5 298 61.9 25.8 59.2
14-day 2-year hydrologically based flow 79.6 630 250 100 254
14-day 5-year hydrologically based flow 45.5 400 124 53.4 113
14-day 10-year hydrologically based flow 32.6 318 85.1 37.2 72.0
30-day 2-year hydrologically based flow 129 1,020 462 162 599
30-day 5-year hydrologically based flow 81.6 588 241 105 307
30-day 10-year hydrologically based flow 63.1 429 165 85.7 194
1-day 3-year biologically based flow 17.0 249 97.7 22.9 17.0
4-day 3-year biologically based flow 23.9 261 122 27.7 30.8
EPA harmonic-mean flow 340 981 788 182 253
5-percent-duration flow 4,870 6,730 4,590 2,470 4,620
10-percent-duration flow 3,340 4,820 3,410 1,370 3,140
15-percent-duration flow 2,610 3,670 2,700 998 2,470
20-percent-duration flow 2,140 3,130 2,270 743 2,060
25-percent-duration flow 1,820 2,650 1,950 615 1,750
30-percent-duration flow 1,560 2,370 1,680 520 1,520
35-percent-duration flow 1,320 2,100 1,470 440 1,310
40-percent-duration flow 1,130 1,890 1,270 373 1,120
45-percent-duration flow 966 1,700 1,100 326 1,000
50-percent-duration flow 820 1,520 960 289 893
55-percent-duration flow 692 1,350 825 257 802
60-percent-duration flow 590 1,210 706 222 709
65-percent-duration flow 503 1,080 604 190 616
70-percent-duration flow 426 939 517 161 513
75-percent-duration flow 356 781 440 137 427
80-percent-duration flow 278 636 363 112 352
85-percent-duration flow 211 534 278 89.4 279
90-percent-duration flow 145 469 199 68.5 200
95-percent-duration flow 83.4 404 131 48.8 96.1
99-percent-duration flow 39.4 293 57.4 22.9 50.6
Variability index 0.53 0.38 0.47 0.51 0.49
03189500 Gauley River near Summersville, WV, 1932–1957
1-day 2-year hydrologically based flow 34.0 536 189 37.7 53.5
1-day 5-year hydrologically based flow 10.5 343 102 13.5 15.3
1-day 10-year hydrologically based flow 5.19 259 70.4 7.56 7.11
3-day 2-year hydrologically based flow 37.7 585 221 42.4 61.1
3-day 5-year hydrologically based flow 11.3 368 119 14.9 17.2
3-day 10-year hydrologically based flow 5.49 273 79.8 8.32 7.84
7-day 2-year hydrologically based flow 46.1 663 295 53.1 80.4
7-day 5-year hydrologically based flow 13.4 396 161 18.6 21.4
7-day 10-year hydrologically based flow 6.30 287 105 10.3 9.11
14-day 2-year hydrologically based flow 61.5 863 417 77.4 108
14-day 5-year hydrologically based flow 17.3 485 213 26.7 27.5
14-day 10-year hydrologically based flow 7.85 340 136 14.4 11.3
30-day 2-year hydrologically based flow 91.2 1,410 646 165 235
30-day 5-year hydrologically based flow 26.5 882 348 56.1 56.4
30-day 10-year hydrologically based flow 12.3 659 237 29.1 22.1
1-day 3-year biologically based flow 6.43 229 105 6.72 8.99
4-day 3-year biologically based flow 9.21 260 129 12.2 9.84
EPA harmonic-mean flow 114 1,180 786 113 41.6
5-percent-duration flow 5,500 8,410 5,020 2,810 4,070
10-percent-duration flow 3,710 5,780 3,540 1,670 2,630
15-percent-duration flow 2,880 4,530 2,830 1,220 2,010
20-percent-duration flow 2,360 3,830 2,390 931 1,590
25-percent-duration flow 1,990 3,310 2,060 752 1,280
30-percent-duration flow 1,660 2,950 1,810 605 1,090
35-percent-duration flow 1,420 2,670 1,580 503 915
40-percent-duration flow 1,190 2,420 1,370 420 792
45-percent-duration flow 1,030 2,190 1,210 359 669
50-percent-duration flow 869 2,010 1,070 301 572
55-percent-duration flow 736 1,820 958 249 478
60-percent-duration flow 607 1,630 850 209 403
65-percent-duration flow 500 1,460 746 172 329
70-percent-duration flow 403 1,300 644 137 254
75-percent-duration flow 316 1,150 543 104 177
80-percent-duration flow 231 983 449 78.4 113
85-percent-duration flow 153 809 365 51.0 69.3
90-percent-duration flow 85.1 653 286 31.7 45.1
95-percent-duration flow 36.8 485 190 18.0 25.4
99-percent-duration flow 10.8 165 90.2 8.6 2.0
Variability index 0.64 0.36 0.43 0.66 0.67
03189650 Collison Creek near Nallen, WV, 1968–1977
1-day 2-year hydrologically based flow 0.04 0.85 0.18 0.04 0.06
1-day 5-year hydrologically based flow 0.01 0.19 0.07 0.01 0.03
1-day 10-year hydrologically based flow 0.00 0.07 0.04 0.00 0.02
3-day 2-year hydrologically based flow 0.04 0.97 0.23 0.05 0.08
3-day 5-year hydrologically based flow 0.02 0.22 0.08 0.02 0.03
3-day 10-year hydrologically based flow 0.00 0.08 0.04 0.00 0.02
7-day 2-year hydrologically based flow 0.05 1.15 0.33 0.06 0.12
7-day 5-year hydrologically based flow 0.02 0.26 0.13 0.03 0.04
7-day 10-year hydrologically based flow 0.00 0.09 0.07 0.00 0.02
14-day 2-year hydrologically based flow 0.10 2.24 0.52 0.13 0.18
14-day 5-year hydrologically based flow 0.02 0.69 0.19 0.03 0.06
14-day 10-year hydrologically based flow 0.01 0.27 0.10 0.01 0.04
30-day 2-year hydrologically based flow 0.16 3.60 1.37 0.23 0.68
30-day 5-year hydrologically based flow 0.08 1.71 0.61 0.10 0.25
30-day 10-year hydrologically based flow 0.05 0.99 0.36 0.06 0.14
1-day 3-year biologically based flow 0.04 0.00 0.00 0.03 0.05
4-day 3-year biologically based flow 0.04 0.00 0.00 0.03 0.05
EPA harmonic-mean flow 0.28 0.61 0.87 0.16 0.19
5-percent-duration flow 17.8 25.1 15.6 8.8 19.3
10-percent-duration flow 11.1 16.0 10.0 3.9 11.5
15-percent-duration flow 8.2 12.5 8.0 2.4 7.8
20-percent-duration flow 6.5 10.1 6.6 1.8 6.3
25-percent-duration flow 5.3 8.4 5.5 1.4 5.2
30-percent-duration flow 4.3 7.3 4.5 1.0 4.3
35-percent-duration flow 3.7 6.4 3.8 0.8 3.7