Scientific Investigations Report 2006–5205
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5205
The methods used to estimate pumpage were predicated on the difficulty in gathering data or measuring pumpage; pumpage is the least known part of the basin’s water budget because of the lack of existing data. Few measured values are available from several pumpage categories because the wells either are not metered (owners do not know how much they use), a well system set-up does not allow direct measurement, information is considered proprietary, or in a few cases, the wells are no longer used. Therefore, various methods were used to estimate pumpage, including using hydrologic judgment based on existing information and previous work. Methods used vary based on the principal PRU of each category. Methods range from compiling and extrapolating compiled (provided) information to estimating that the full appropriated quantity is the best pumpage estimate for a category. For rights in a category that include certain additional PRUs, such as DM for workers, the Washington State Department of Health’s (DOH) Water System Design Manual (Washington State Department of Health, 2001a) was used as a guide for estimating additional pumpage for those PRUs.
The start date associated with pumpage is assumed to be the well completion date and that the well is then used for its designated PRU. When the well-completion date was unknown and the well had a water right, the start date was assumed to be the priority date of the water right. For example, if an irrigation well was drilled in 1920 and its associated right had a priority date of 1950, the 1920 date would be used as the start of irrigation pumpage. Examination of numerous drillers’ logs indicates that this is a reasonable assumption, especially for wells drilled prior to about 1970. Exceptions for defining the start date of public water supply pumpage and domestic pumpage are described below.
It is also assumed that the methods are applicable for any particular year. This implies that the same amount of water would be used by a particular user or users in any year. For example, the assumption is that a household uses the same amount of water each year. However, pumpage varies year-to-year for various reasons. It was beyond the scope of this study to attempt to estimate interannual variations that may occur for any particular category of pumpage due to changing water-use practices.
For this study, public water supply (PWS) withdrawals primarily included water systems that are part of the DOH’s Group A and Group B systems. Group A systems generally have 15 or more service connections and Group B systems generally have 2 to 14 service connections. For this study, Group A water systems serving incorporated areas, referred to as municipal systems, were considered separately from other Group A systems. The DOH database for the three-county area has 325 Group A systems that serve about 302,000 people and 1,285 Group B systems serving about 10,600 people. Group A systems principally serve both municipalities and residential developments. Not all these systems are in the basin boundaries. Water-right wells with a single PRU of DM (some also may have a second PRU of IR, but the IR part of the right is minimal compared to the DM part) that provide drinking water to households, but are not part of a Group A or B system also are included as part of the PWS category.
Twenty-four water purveyors in incorporated areas, generally representing the largest Group A systems (municipalities), were asked to provide existing records for pumpage from 1960 through 2000 and the corresponding populations served. All purveyors provided at least monthly records for some years for that period and population-served data for 2000. Several purveyors provided weekly or daily values, which were compiled into monthly values. Provided pumpage values represent PWS and include all water pumped by a municipality for distribution.
Population-served data were analyzed in conjunction with the State of Washington, Office of Financial Management census (from the U.S. Census Bureau [U.S. Census Bureau, 2004]) and intercensus (estimated annual population between 10-year U.S. Census Bureau surveys, by county, for incorporated and unincorporated areas) data (Washington State Office of Financial Management, 2002) to calculate a ratio of population served to census population for each year of available data for the municipalities. Calculated ratios were then multiplied by census or intercensus data from 1960 through 2000 to estimate an annual population served; the final population served estimates were for each system for years with no available population-served data.
Available pumpage and population-served data then were used to calculate an average annual per capita pumpage rate for each municipality for the period of available data. Average per capita rates varied from 38 to 554 gal/d with 75 percent less than 180 gal/d and 50 percent less than 129 gal/d. The per capita rate was then multiplied by estimated population served to obtain annual totals of pumpage for years without available data. Calculations resulted in a complete record of observed or estimated pumpage for the 24 systems for 1960 through 2000. Implicit in these calculations is that the non-drinking water part (commercial, industrial, and irrigation) of the total pumpage remained constant over time. This part is known to change with time because total industrial and commercial use of water is slowly declining (Dion and Lum, 1977). Data provided by larger systems indicated that the commercial and industrial part of total pumpage ranged from about 4 percent to as much as 60 percent; the larger values are for small municipalities that seasonally provide a large quantity of water to fruit and vegetable processing plants. Except for some older unused municipal wells, most wells have an identified latitude and longitude based on either site visits or global positioning coordinates provided by the municipality or DOH.
All other Group A and B water suppliers were asked if pumpage data were available. These non-municipal systems typically provide water to households and do not generally provide water for industrial and commercial purposes. Twenty‑three Group A systems and 40 Group B systems provided pumpage information. Population-served data for these systems were obtained from the DOH’s, Office of Drinking Water, web site (Washington State Department of Health, 2001b). Based on pumpage data and population served, a per capita rate was calculated for each system for each year that withdrawal data were available. If a per capita rate appeared too low or too high (a potential outlier), the system operator was contacted to obtain additional information or to verify the provided information. Rates for the systems ranged from 10 to 1,800 gal/d and 90 percent of the values were less than 600 gal/d. The resulting per capita values were then used to calculate a basin-wide average per capita rate of 251 gal/d, weighted by population served. However, the three highest rates (1,800, 1,040, and 935 gal/d) were not used in the calculations because the highest value appeared to be in error and the next two highest values, although not unreasonable based on reported values for eastern Washington (Washington State Department of Health, 2001a), appeared to be outliers for actual pumpage in the basin. A basin-wide average was calculated because data from individual systems displayed no spatial trends. Data for municipalities were not used in the calculations because their usage is not representative of smaller systems, which do not supply commercial and industrial water and generally do not supply high density, multi-residential properties such as apartment buildings. For systems in the surface-water irrigation districts (fig. 10), a reduced average rate of 109 gal/d was calculated based on the average of several larger systems in irrigation districts. The reduced rate was used because many households in these districts use surface water for lawn and garden watering.
The appropriate average rate then was multiplied by population served for all years for all systems with no available pumpage data. Although an average rate should capture the overall pumpage, estimates for some systems will be too small or too large. Locations for many of the Group A systems were identified using a Global Positioning System (Washington State Department of Health, written. commun., 2003); whereas, most of the Group B systems have locations at the center of a section, quarter section, or quarter‑quarter section. Estimated start year for a system is “effective source date” from DOH’s database; some systems probably were operating prior to the effective source date. About 150 systems did not have population served data and no estimates were made for these systems, which principally include campgrounds, small stores, churches, taverns, and a few commercial operations.
Pumpage for PWS varies greatly on a seasonal basis. To estimate month-to-month variation in pumpage, a percentage of annual pumpage for each month was calculated. This percentage was based on total pumpage for all systems that provided information for the most current year, usually 2000. In turn, pumpage for each month was totaled for all systems and then divided by the annual total. These calculations yielded an effective monthly percentage of annual pumpage for the basin. These values will be used for other components of this study to estimate monthly pumpage for the systems with no available data.
Domestic pumpage is composed of two parts: pumpage for ground-water rights and pumpage from exempt wells. Domestic pumpage is negligible for ground-water rights compared to exempt-well pumpage, but it is important to obtain an accurate estimate as possible for total water-right pumpage in the basin. Excluding some dairies, other allowable potential pumpage from exempt wells was not estimated as part of this study because of lack of information.
Ground-water right pumpage estimates were made for all wells with a PRU of DS as its principal use. Fifty‑nine associations were for wells with rights with a single PRU of DS and 4 rights had a second PRU of either HE or FP. For wells outside of irrigation district boundaries, 251 gal/d per capita was used to estimate a value for 2.3 persons per household, yielding a pumpage rate of 0.65 acre-ft per household. For wells in irrigation districts, 109 gal/d per capita, described previously, was used to estimate a value for 2.3 persons per household, yielding a pumpage rate of 0.28 acre-ft. One right had a small associated acreage for application of water; IR was not a PRU and this right was not included as part of the irrigation estimates (except for two rights, all pumpage associated with the irrigation estimates include a defined PRU of IR). Based on water requirements for a well-watered lawn, estimates are that 2.5 acre-ft/acre was pumped for lawn watering.
Two DS rights were for businesses. For a smaller business 250 gal/d (0.28 acre-ft) was assumed to be pumped and for a larger business 500 gal/d (0.56 acre-ft) was used as the pumpage estimate. Another right was for a nursing home, but notes from a field visit of the property’s well indicated that the well was used only for irrigating about 1 acre in summer, and 2.5 acre-ft was assigned to this right. One right was for a small Forest Service campground. Assuming 20 people per day used 20 gal/d during May through October resulted in a pumpage estimate of 0.22 acre-ft. One right had an additional PRU of HE for a domestic ground-water heat pump for which a value of 0.01 acre-ft was used; this quantity is returned through another well. Two rights in an irrigation district had an additional PRU of FP with 4–8 allowable acres. Frost protection pumpage for these two rights was assumed to be negligible.
Similar methods were used to estimate the domestic part of pumpage for other pumpage categories with principal PRUs of IR, FP, HE, CI, and (or) ST and a secondary PRU of DS. These latter pumpage estimates are not included as part of this category because pumpage for these other principal PRUs is much larger than for a single household; that is, the estimated pumpage is generally much larger for the above PRUs than for the DS part. In addition, to retain total pumpage associated with a right and a well, the estimates for the DS part are included in the total for the right under the other categories.
Average per capita pumpage rates (109 and 251 gal/d) calculated from data provided by water purveyors were used to estimate the pumpage by exempt wells (wells not requiring a water right, primarily used for self-supplied domestic use, and use less than 5,000 gal/d). To use the per capita rates, an estimate of population served by exempt wells was first made. The 2000 U.S. Census Bureau data for population in census blocks (U.S. Census Bureau, 2004) for the unincorporated part of the study area (fig. 11) were used in conjunction with population served information for all Group A and B systems to estimate the population using exempt wells.
The PWS population served was subtracted from the census block population to obtain a population estimate for exempt wells. The average per capita rate (251 gal/d) was then multiplied by the exempt population in each block to estimate exempt pumpage by block. For blocks in irrigation districts, the reduced per capita rate (109 gal/d) was used to estimate exempt pumpage. Using exempt population and households per block, an estimate also was made of the number of exempt wells in a block.
Based on estimated population using the 2000 census and the State of Washington Office of Financial Management intercensus data (Washington State Office of Financial Management, 2002), an estimate also was made for 1995. A ratio was calculated for intercensus 1995 population to 2000 population for unincorporated areas, by county. This ratio then was assumed to apply to all unincorporated blocks, and the 2000 population estimate in each block was multiplied by the ratio. Population served in 1995 for the PWS systems was then subtracted as above. The exempt pumpage calculations were then made using the same methods used to estimate pumpage for 2000. This process was used to estimate pumpage for 5-year increments to 1960. However, DOH’s information on PWS systems did not start until 1970. For this study, Group A and B systems operating in 1970 were assumed to be also operating in 1960 and 1965. Therefore, exempt pumpage was estimated for each unincorporated census block for 1960‑2000, but the actual location of pumpage in a census block is not known.
Irrigation pumpage estimates were made for most wells with irrigation rights and allowable acres in the WRTS database. A total of 2,226 rights had allowable acres for irrigation, and all but 2 rights had IR as a use. These latter two rights had a PRU of DM with large allowable acreage known to be associated with either pastures or orchards. Much of the pumpage for these two rights is associated with irrigation, and estimates are that the DM part of the appropriated right was for workers’ use. Seventeen rights with a single PRU of IR with a total annual quantity of about 4,220 acre-ft were for municipalities, and withdrawals for these 17 rights are included as part of the PWS estimates. Fifty-eight rights were associated with non-municipal PWS with a total allowable acreage of about 1,010 acres. Pumpage for these rights is included as part of the PWS pumpage because the irrigation part is assumed to be accounted for in the PWS estimate. One right with allowable acreage was for a PRU of DS and no PRU of IR; the estimate for this right is included in the domestic right estimates. As a result, 2,150 rights were analyzed for pumpage and these rights include about 123,400 acres of allowable irrigated lands.
Pumpage estimates were derived using allowable irrigated acres, annual acre-feet application rate (the water duty—appropriated annual rate divided by acres), crop type, and estimates of average crop-water use. For the lower part of the river basin that included parts of Yakima and Benton Counties, Pacific Power provided power consumption data for their irrigation pricing-schedule users aggregated by zip code due to the proprietary nature of the information (Pacific Power, written commun., 2001). The power information was used to obtain a coarse estimate of pumpage for this part of the basin based on generalized power consumption-pumpage equations. This estimate was used to help assess the reliability of the irrigation pumpage.
This study originally was designed to use a detailed power-consumption method to estimate pumpage for many larger users. This method relies on accurate readings of well discharge using an acoustic velocity flowmeter, accurate pipe thickness measurements, power records, transformer information, and well information. Visits to more than 300 wells resulted in only 18 reliable measurements because few well systems met the criteria for flowmeter use. For well-pumping systems where this method was used, calculated pumpage was used as the estimate and also to estimate the reliability of the crop-water use method.
To apply the crop-water use method, a crop-type GIS database was generated using several data sources. Reclamation provided (1) a GIS database for the basin that identified irrigated lands, but no crop type, and (2) GIS databases for crop types for several smaller areas (E. Young, Bureau of Reclamation, written commun., 2003). Kittitas Conservation District provided a crop-type distribution for most of Kittitas County (Kittitas Conservation District, written commun., 2003), and South Yakima Conservation District provided information for Roza and Sunnyside Valley Irrigation Districts (fig. 10) (South Yakima Conservation District, written commun., 2004). Land use/cover for the basin was obtained from the USGS’s national database (Homer and others, 2004), and a detailed crop-type coverage for a small subbasin near Granger was developed by the USGS as part of the National Water Quality Assessment Program. A field survey was conducted as part of this study for the Wapato Irrigation Project (fig. 10) to identify fields with orchards, vineyards, and hops. Additional field surveys were completed in selected areas identified as irrigated lands from either the Reclamation or the USGS data sets, but the crop types were not known. A 2004 geodatabase of fields with irrigated crops was obtained from Washington State Department of Agriculture (DOA), Pesticide Management Division (T. Maxwell, Washington State Department of Agriculture, written commun., 2005). This database contained information on field size, crop types, and irrigation methods, aggregated to the section level. However, determination could not be made where a field was in the section because information was at the section level, and the geodatabase was not used to develop the crop-type database. However, the geodatabase was used for other checks on crop type. Land-use/cover information for the basin was combined into a single spatial database, starting with the least detailed data and substituting in the more detailed data sets. The resulting database was assumed to represent all years for which irrigation pumpage was estimated.
Each water-right well then was assigned to the crop type at the well. The resulting crop types at wells were compared with DOA data, allowable acres, and PRU to: (1) determine their reasonableness and (2) estimate a crop type for wells associated with irrigated lands having unknown crop types. For each right, the allowable annual application rate (the water duty) was compared to a crop water-use rate, and the smaller value was multiplied by the allowable acreage to estimate annual pumpage. The crop water-use rate was an average for each crop based on 50 years of daily calculations of potential crop evapotranspiration, which does not account for off-season precipitation or soil moisture. An irrigation-efficiency factor was not applied to the rate because the crop rate could be high, the rates varied by as much as 3–4 in. over the 50-year period, and precipitation was not accounted for. Overall, using such an average rate without an efficiency factor should capture the average pumpage. This method of applying crop water-use rates was used by Cline and Collins (1992) and Van Metre and Seevers (1991) to estimate pumpage in the central Columbia Plateau and proved to be reliable.
Power consumption methods for estimating pumpage are well documented and were previously used to estimate pumpage in the central Columbia Plateau (Collins, 1987; Cline and Knadle, 1990; Van Metre and Seevers, 1991; Cline and Collins, 1992). In one method, an effective total operating head value would be needed for each zip code area with the aggregated power data. Obtaining such a value would be difficult if not impractical because of large variations in well construction and depth in a zip code area.
Another power consumption method relates a known pumping rate to power consumption to derive a power‑consumption coefficient (PCC), which is energy consumed per acre-ft of water pumped in units of kilowatt hours per acre-ft (kWh/acre-ft). The 18 PCC values calculated in this study ranged from 418 to 3,563 kWh/acre-ft, with a median of 970 kWh/acre-ft. Based on numerous measurements from previous studies, the PCC generally ranges from about 400-500 kWh/acre-ft for pressure systems (Hurr and Litke, 1989).
Collins (1987) used flowmeter and power consumption data for the Columbia Plateau, Oregon, to develop two equations relating annual power consumption to annual pumpage:
Q = 0.000865 * K + 39.09 (1)
Q = 0.00193 * K + 66.88 (2)
where
| Q | is annual pumpage, and |
| K | is annual power consumption. |
Equation 1 was for basalt wells and equation 2 for the sedimentary material overlying the basalts.
For each zip code area in the lower basin with power consumption data, pumpage was estimated based on the 400 and 970 kWh/acre-ft PCC values and equations 1 and 2. Together, the four calculated values of pumpage provided a range in potential pumpage. To differentiate between surface- and ground-water power consumption for irrigation in a zip code area, total irrigated area in a zip code area was estimated from the land-use/cover data. The percentage of irrigated lands in a surface-water irrigation district was then calculated. The remaining percentage was multiplied by the power consumption to estimate ground-water power consumption in an area, which was used with the PCC values and equations 1 and 2 to estimate a potential range in pumpage. This method assumes that power consumption for surface- and ground‑water systems is the same.
Eight hundred eighty-one rights had an additional PRU of DS. For these rights, 0.40 acre-ft (about 154 gal/d per capita) was added to estimated irrigation pumpage, under the assumption that a well served a household, but lawn and garden watering and other uses are accounted for with the irrigation pumpage. Average per capita pumpage for November–February is 154 gal/d for the non-municipal PWS systems that provided data. If the right also had FP or FR listed as a PRU, the 0.4 acre-ft also was assumed to account for these uses.
For rights with an additional PRU of ST (232 rights), the irrigation part of pumpage was previously estimated. A few of these rights appear to be only for stock-water use, but the majority has a reasonable amount of allowable irrigated acres, suggesting that most of the pumpage is for irrigation. Therefore, the irrigation pumpage estimate was assumed to be a base-level estimate for all rights with an associated ST use. Excluding rights with a PRU of ST, the irrigation pumpage estimate averaged about 69 percent of the appropriated right and had a standard deviation of 21 percent, whereas the rights with ST averaged 61 percent. Under the assumption that all ST rights use water for livestock, the base-level estimate was increased to 69 percent of the appropriated water.
One-hundred and forty-four rights had an additional PRU of DM, DG or MU. Pumpage for these rights greater than the base-level irrigation pumpage was estimated in two ways because these rights generally are in two categories. The first category is for water supplied to workers and the second category is water supply for households. The second category also included some rights that appear to supply public water, but they are not part of the Group A or B systems. The category for a right was estimated based on ownership, information from the drillers’ log, and information on the appropriated values associated with the right.
For rights categorized as supplying drinking water for workers, 300 gal/d or 0.34 acre-ft was estimated as additional pumpage. The 300 gal/d is assumed to account for farm uses such as equipment cleaning. For the rights estimated to supply drinking water to multiple households, the average water duty was calculated for rights with a single PRU of IR. The amount of appropriated water greater than this average water duty (3.7 acre-ft/acre) was calculated. Based on a typical value of 1 acre-ft of appropriated water for a household, it was assumed that the remaining appropriated water greater than the average water duty represented the number of households. For example, 10 acre-ft remaining after applying the average water duty would represent 10 households. The estimated part of pumpage for drinking water supply for the right was then estimated as acre-ft available multiplied by the 0.4 acre-ft used for the DS estimates.
For rights with an additional PRU of HE and (or) CI, 50 percent of the appropriated quantity remaining after the irrigation, livestock, and domestic pumpage were subtracted was added as additional pumpage. For a single right with a PRU of DY, 80 percent of the remaining appropriated quantity was added. This right was associated with both irrigated crops and dairy operations. For the five rights with a PRU of EN and the two rights with a secondary PRU of RE, pumpage for these uses was assumed to be accounted for in the IR part.
A few but unknown number of standby/reserve rights may be supplemental for use in any year when the allowable withdrawal is met for the surface-water right. In addition, the lack of information about the allowable duty, on which rights are usable in any proratable year in contrast to drought/emergency rights, on the different levels of prorating, and on the actual use of standby/reserve water makes it difficult to estimate the actual pumpage for the standby/reserve irrigation rights. Thus, standby/reserve pumpage was estimated using the same methods used for estimating primary pumpage. However, the estimated pumpage would be valid only during extreme prorating years (all rights are available and needed), and the estimated value would change by some factor depending on the prorating level. How the estimated standby/reserve pumpage may change in prorating years is described in a following section that presents the estimates for the irrigation category.
Distribution of pumpage from any well over the irrigation season primarily depends on the particular crop or crops grown. In addition, soil moisture, pumping lift, and irrigation method also affect the temporal distribution of pumpage. To obtain a general understanding of the temporal distribution of irrigation pumpage, a simplified method was developed. Using this method, potential water needs of a crop type for each day in April through October, regardless of soil moisture content, were calculated for a 50-year period for 13 most commonly irrigated crops in the basin. For each crop type, the average percentage of total seasonal potential use for each month was then calculated. The 13 values were averaged for each month to derive an average percentage of total curve. The resulting average monthly percentages were then multiplied by total annual pumpage for 2000; pumpage was also separated by primary and standby/reserve rights. No weighting was done based on prevalence of a particular crop type in the basin. This distribution would be different for each crop type because of different plant water needs at different growth stages and the total amount of water pumped varies for a particular crop in the basin. For example, more apples are irrigated with ground water than beans, and the water needs and growing season differences between these two crop types are more than 1 acre-ft/acre. In addition, the curve does not represent pumpage in November for selected wine grapes. The distribution would also vary spatially for each year due to climatic factors, soil properties, and changing crop patterns. Thus, these curves represent a generalized or an effective distribution.
Frost protection is instituted to protect fruit trees from frost damage during early emergence through budding. Frost protection was listed as a use for 209 water rights. Of these, 184 also had a PRU of IR. Of the remaining 25 water rights, 21 had FP as the only PRU and 4 had an additional PRU of either DS or DM. Frost protection accounts for only a small part of annual pumpage compared to irrigation pumpage for the rights with these PRUs; most of these rights have allowable irrigated acres typical of farms in the basin. Therefore, pumpage estimates for frost protection for the 184 rights were assumed to be accounted for in the irrigation estimates.
The 21 water rights with FP as the only PRU were associated with wells in an irrigation district, have a post‑1976 priority date, or have a small annual appropriated value. Many of these wells also have a second right with a PRU of IR. The actual pumpage associated with FP from these wells that are either used only for frost protection or have a second right would be small compared to the other categories of uses, especially due to the fact that frost protection is not instituted very often; the average number of frost free days in the lower part of the basin, where most of the orchards are, is on the order of 180–200 days. Therefore, pumpage for these 21 rights, which total 356 acre-ft, was not estimated and is assumed to be either negligible or included in irrigation estimates for wells with a second right with a PRU of IR. These 21 rights account for less than one-tenth of 1 percent of the total appropriated annual quantity in the basin.
For the four rights with an additional PRU of either DS or DM, one was associated with a right for the same well with PRUs of IR and DS; therefore, the DS part was included as part of the right associated with irrigation use. Pumpage for the two rights with a PRU of DM, are included under the PWS estimates. The remaining right had a PRU of DS and the associated DS pumpage is included in the domestic right pumpage.
There are 273 rights with a PRU of ST associated with them, which account for about 305 POWs. There were three classes, accounting for 68 POWs, of livestock rights for which ST was a principal PRU. The first is for the rights with a single PRU of ST, typically associated with dairy, ranching, and packing operations. Two other classes have an additional PRU of DM, DS, or CI/EN. The above three classes were assumed to have primary rights, even if the right is in an irrigation district because they do not have a PRU of IR. For these rights, the appropriated acre-ft right, typically 20–40 percent of the maximum instantaneous rate (in gal/min), was estimated as the pumpage. No additional pumpage was added for the other purposes because the full right was assumed to be used.
All remaining ST rights also have a PRU of IR with previously estimated irrigation pumpage. A few of these rights appear to be only for stock-water use, but most have a reasonable amount of allowable irrigated acres, suggesting that most of the pumpage is for irrigation. Pumpage estimates for these rights are not included as part of this category in order to retain the total estimated pumpage associated with a well and right. Additional pumpage for livestock use greater than the base-level irrigation estimate is included with a right associated with irrigation use. One ST right had an associated PRU of IR, but no allowable acreage; the pumpage estimate for this right was set to the appropriated value.
Also included under livestock pumpage is pumpage for rights associated with dairy operations. Fifteen rights had a PRU of DY, 10 of which also have a PRU of DS or DM. Dairies typically use their entire appropriated quantity (J. Kirk, Washington State Department of Ecology, written commun., 2005). Estimated pumpage for these rights also was set to the appropriated value. In addition, at least 19 smaller dairies currently operate using an exempt well. For these dairies, pumpage was estimated as the maximum allowed, 5,000 gal/d or 5.6 acre-ft. An approximate location for wells associated with these 19 dairies was estimated based on a dairy’s address. Operations for most smaller dairies started in the late 1980s, which is consistent with the water-right priority dates for most dairies.
Pumpage estimates for this category principally are for 151 rights with a PRU of CI and (or) HE. Ten rights are without these PRUs, 6 have a principal PRU of RW, 2 have a PRU of FR (fire protection for 2 food processing plants), and 2 have a PRU of EN associated with industrial operations.
Pumpage was estimated for two subcategories using similar methods. The main subcategory includes all rights containing a PRU of CI, 3 rights with PRUs of HE and DM or DS, and the 10 rights described above. This subcategory has 118 rights with 143 POWs. Total maximum instantaneous rate for these rights is 29,429 gal/min and the annual quantity is 24,604 acre-ft. Six rights did not have an appropriated annual quantity in WRTS, which is needed to estimate pumpage. Based on the average ratio of instantaneous values to annual values for rights with similar instantaneous values, these 6 rights were estimated to account for an additional 784 acre‑ft. The instantaneous rates for this subcategory ranged from 5 to 2,250 gal/min and averaged 251 gal/min, and the annual quantity ranged from 2 to 2,024 acre-ft and averaged about 217 acre-ft.
Rights with a single PRU of CI account for 64 of the 118 rights in the first subcategory. In addition, 15 rights have an additional PRU of HE and 17 rights have an additional PRU of DG, DM, or DS. The remaining rights have various mixtures of PRUs. Two rights with smaller appropriated quantities also had a PRU of IR, but no allowable listed acreage; therefore, they are included as part of commercial and industrial pumpage.
The second subcategory contains rights with a single PRU of HE. Thirty-three rights had a single PRU of HE represented by 40 POWs. Rights with a PRU of HE are generally associated with heat pump use and (or) refrigeration and are considered commercial and industrial pumpage. The total maximum instantaneous rate for these rights is 6,682 gal/min and the annual quantity is 6,219 acre-ft. Similar to the other subcategory, 7 rights had no listed annual quantity; to estimate an annual quantity an average ratio was calculated for the other 26 rights. Based on this ratio (0.94), these rights have an estimated annual quantity of about 720 acre-ft, and account for about 12 percent of the above total; note that one of the 7 rights had the same instantaneous value and use (heating and cooling of about the same size building) as another right and thus the ratio was not used to estimate the annual quantity but the annual value for the other right was assumed to be the best estimate for its right. The instantaneous rates for this subcategory ranged from 7 to 700 gal/min and averaged 202 gal/min; the annual quantity ranged from 1 to 960 acre-ft and averaged about 189 acre-ft.
Withdrawal information for this pumpage category was limited, with information available for only 13 rights. This lack of information was due to several factors, including one or some combination of: (1) owner did not know how much was withdrawn and no metering; (2) wells were no longer used for a component of the operations, such as heat exchange, resulting in unavailability of historical withdrawal information; (3) building was under new ownership or demolished and the right is no longer used; (4) owners were unaware of a well on the property and if there was a well, did not know when it was last used; and (5) owner-property-well could not be found (the well may no longer be in existence, but the end of use date is unknown).
Values provided ranged from about 0.2 to 137 percent of the right. Excluding the high value, the other values can be grouped into two categories: (1) a lower percentage category averaging about 4 percent and (2) an upper category averaging about 25 percent. The smallest ratio (0.2) is anomalous because its withdrawal is primarily representative of the second PRU of DG. This well serves a complex of non-industrial buildings and the PRU of CI could be related to older uses. In addition, a deep well on the property has a right to irrigate 500 acres and may provide water to any CI operations. The largest value (137) is for heat exchange of a large multi-story building and is atypical because the requirements of the building were not accounted for when obtaining the right; the withdrawals for this right are returned back to the ground-water system through an injection well. Values averaging 4 percent are related to either smaller operations or the right is primarily used for heating and cooling buildings. The lower values primarily are related to HE uses and the 25 percent value applies to rights that include large-scale operations, including manufacturing and fruit and vegetable storage and processing. In addition, a value of 14 percent was obtained for an HE use that includes refrigeration for cold storage, and would be appropriately applied to such HE rights.
To estimate pumpage for the rights with no available information, a ratio (percentage of appropriated quantity) was assigned to each right and was then multiplied by the appropriated annual quantity. It was assumed that no water was withdrawn for fire protection for the 2 rights with a single PRU of FR. The types of operations and use of water for the 13 values described above, allowed for a reasonable assessment of which ratio to apply to which right.
For rights with a second PRU of DS, 0.40 acre-ft additional pumpage was added; the same value used for the irrigation category. For rights categorized as supplying drinking water for workers (PRU of DM or DG), 300 gal/d or 0.34 acre-ft was estimated as additional pumpage for the right.
Pumpage estimates for this category are for all 151 rights. A few of these rights are no longer used and withdrawals for additional rights may have also stopped. For these cases, the end date of use is not known. The authors chose to conservatively estimate that all wells were withdrawing water as of 2000 because during the entire estimated pumpage period (1960-2000) it was only towards the end that a few wells were no longer used.
Pumpage associated with fish and wildlife propagation principally is related to fish propagation, and in particular, for hatchery operations that account for most of the appropriated quantity and pumpage. Ten rights had PRUs of WL and FS, and data were available for 7 of the rights. Appropriated quantities for two remaining rights were smaller compared to the other rights; the larger rights have annual appropriated quantities on the order of 600 to 8,000 acre-ft. Based on the provided information, 90 percent of the appropriated quantity was used as the estimate for one of the rights without data that had a reasonable quantity associated with it. The other right is associated with a PRU of WL and serves a household, barn, and some fields that were obtained for wildlife. For this right, 3 acre-ft was presumed to be used based on property usage described by Washington State Fish and Wildlife (oral commun., 2005). One hatchery right was for supplemental use to surface-water sources, and according to Washington State Fish and Wildlife personnel, the well is no longer being used. No estimate was made for this right because it was unknown when it was used for supplemental supply and it has not been used for a reasonable period of time.
Pumpage values provided ranged from detailed values, from the start of use, to a daily and (or) annual value. For cases where only a daily value or annual value was provided, the value was assumed to be used for every year from the start of use.
In addition, information was available about the quantity pumped from two wells also used for hatchery operations. Although these wells do not have a right, they are accounted for under these categories because the wells are used for fish propagation and account for a reasonable amount of total pumpage for this category.
A water-right claim is a document declaring a claim for water use and may be valid if it describes a ground-water use before July 1945. Most claims were filed during an open filing period authorized by the 1967 Water Right Claims Registration Act or the 1998 reopening of the Act. Currently, a claim can be validated only through judicial processes involving filing applications, obtaining permits, and field inspections of the well in question. A favorable ruling results in the granting of a water right.
In 2005, about 16,605 ground-water claims were in effect in the Yakima River Basin (R. Dixon, Washington State Department of Ecology, written commun., 2004). Some of these claims were filed by well-owners who already have a right to use ground water. Other claims are for wells that do not require them. These wells may be covered under exempt status because they use 5,000 gal/d or less for stock watering, single or group domestic use, industrial use, or for lawns and commercial gardens of less than one-half acre. The basis of the analysis of claims was to estimate pumpage for claims that may not have been estimated in another pumpage category, and not to determine the validity of a claim.
WaDOE reduced the number of claims for which pumpage was estimated for this study through an office review of claims on file (J. Kirk, Washington State Department of Ecology, written commun., 2005). WaDOE first eliminated “short forms,” using the reasonable assumption that the short form was most likely filed for wells that qualified as exempt wells and would be accounted for in the other pumpage estimates. This step reduced the number of claims to about 7,800.
Next, claims with a PRU of DG were eliminated. The same assumption was made for this step as used in the first. About 4,100 claims had a PRU of DG, yielding about 3,700 remaining claims.
WaDOE then eliminated claims with two PRUs of DG and ST and (or) a single PRU of ST. The same assumption was used, as well as assuming that larger claims are accounted for in other pumpage (principally water-right) categories. Following this step, about 2,800 claims remained.
Last, WaDOE used the listed water source on the claim as a criterion for elimination. Some claims list tile drains, springs, creeks, sumps, lakes, and other surface-waters as sources. These were mistakenly filed as ground-water claims or were not considered surface-water sources during the on-going adjudication process. Eliminating these claims reduced the number to 2,540 for analysis by USGS.
Project staff then analyzed each remaining claim based on location (TRS), PRU, annual claimed quantity, and the name associated with the claim. For each claim, the WRTS database was searched to determine if there was a matching right (PRU, quantity, and name) for the claim. If a matching right was found, the claim was eliminated under the assumption that the owner made an unnecessary claim for a valid right. If a match could not be found in WRTS, the digital well information files developed during this study and WaDOE’s on-line database were searched by name and TRS for a well that could be associated with the claim. When a match was found and the well was relatively new or in some cases only post-1945, the claim was eliminated under the assumption that the claim was made on a ground-water use that was post-1945. These processes reduced the number of claims to 2,018.
Next, 532 claims were eliminated because although they may have a listed PRU, there was no listing for the claimed quantity or acres irrigated. Without examining each original claim form, estimating pumpage for such a claim was impossible. Next, there were 451 claims that included a PRU of IR with listed allowable acres of 1 acre or less. Three-hundred and fifty of these claims had 2 PRUs of DG and IR or 3 PRUs of DG, IR, and ST. The remaining 101 had a single PRU of IR. Based on the assumption that these claims may meet exempt status and would be accounted for in other pumpage categories, they also were eliminated. If these 451 claims did not meet exempt status, there might be on the order of 900 to 1,200 acre-ft of additional pumpage not accounted for by treating these claims as covered under the domestic exempt well category. Last, 2 claims were for a municipality whose pumpage is already accounted for under the PWS estimates, and these claims were eliminated. These processes reduced the number of claims to 1,033.
The next step was to plot the well locations, which was supplied by WaDOE (J. Kirk, Washington State Department of Ecology, written commun., 2005), for the remaining claims because prior to 1945, construction of water wells was primarily concentrated in certain areas. Plotting the location of the claims based on their PRU and acres irrigated thus allowed the project staff to estimate if additional claims could be eliminated. The resulting plot showed that the distribution of the remaining 1,033 claims was throughout the basin, indicating that it would be problematic to eliminate claims solely based on where they were located. A decision was made to examine claims with larger claimed irrigated acreage and a PRU of IR. For this final step, irrigated acres from the DOA’s geodatabase in the TRS of the claim were compared to the claimed irrigated acreage to determine if the number of acres in the same section could account for the claimed acreage. If the claimed acreage was greater than the geodatabase acreage by some reasonable amount, then the claim was eliminated. For example, if the claimed acreage in a TRS was 160 acres and the geodatabase had identified only 1 field of 10 acres in the TRS, then the claim was eliminated. In contrast, if the geodatabase identified 2 fields, 1 of 70 acres and 1 of 60 acres, project staff assumed that together the acres approximated the claim and the claim was not eliminated. This last step assumes that the TRS for the claim is correct and that the geodatabase of irrigated fields is accurate. Based on this final step, the number of claims analyzed for pumpage was reduced to 924. Nine-hundred and sixteen of the remaining claims are principally for irrigation and stock use and the remaining 8 claims are principally for commercial and industrial uses. About 200 claims account for 75 percent of the total claimed irrigated acreage and only 80 claims account for about 50 percent of the total claimed acreage. No information exists on which well is associated with a particular claim because many wells usually are in the TRS of a claim. Therefore, the pumpage location is based on the center of the section identified in WRTS.
Pumpage was estimated for claims with irrigated acreage using the same methods used for estimating pumpage for the irrigation category. However, only 12 claims with irrigated acres listed the annual quantity. Water duty assigned to each claim was based on a crop type; therefore, unlike the irrigation category, the crop-water duty could be compared only to the claimed water-duty for the 12 claims to determine the smaller of the 2 water-duty values. Pumpage for 8 claims for commercial and industrial uses was estimated using the same method as used for the commercial and industrial category. Pumpage for the commercial and industrial part of these 8 claims was estimated as 25 percent of the annual quantity. For the 543 claims that also had a PRU of DG, it was assumed that this PRU was for supplying drinking water to workers, and about 300 gal/d or 0.34 acre-ft was estimated as additional pumpage. Not enough information was available to estimate the livestock use part of pumpage for the 249 irrigation claims that also had a PRU of ST because there was no claimed annual quantity.
U.S.
Department of the Interior | U.S. Geological
Survey
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