Report of the River Master of the Delaware River for the Period December 1, 2014–November 30, 2015
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Acknowledgments
The Office of the Delaware River Master’s (ODRM) daily operation records were prepared using hydrologic data collected daily. Data for these records were collected and computed by the ODRM or were provided by the following agencies and utilities. Data for streamflow of the Delaware River at Montague, New Jersey, and other locations and tributaries in this report were provided by the U.S. Geological Survey (USGS). Data for the Pepacton, Cannonsville, and Neversink Reservoirs were provided by the New York City Department of Environmental Protection. Data for Lake Wallenpaupack were provided by the PPL Corporation (transferred to Talen Energy as of June 1, 2015). Data for Rio Reservoir were provided by Eagle Creek Renewable Energy, LLC. The contributions from these organizations are greatly appreciated. The National Weather Service offices in Binghamton, New York, and State College, Pennsylvania, provided quantitative precipitation forecasts and some precipitation data. Marie Owens (Hynes), Margaret Philips, and Amy McHugh, all of the USGS, assisted with and contributed to this report by collecting, organizing, and reviewing data.
River Master Letter of Transmittal and Special Report
Office of the Delaware River Master
U.S. Geological Survey
415 National Center
Reston, VA 20192
April 11, 2024
The Honorable
John G. Roberts, Jr.
Chief Justice of the United States
The Honorable
John Carney
Governor of Delaware
The Honorable
Phil Murphy
Governor of New Jersey
The Honorable
Kathy Hochul
Governor of New York
The Honorable
Josh Shapiro
Governor of Pennsylvania
The Honorable
Eric Adams
Mayor of the City of New York
No. 5, Original—October Term, 1950
State of New Jersey, Complainant,
v.
State of New York and City of New York, Defendants,
Commonwealth of Pennsylvania and State of Delaware, Intervenors.
To the Chief Justice of the United States:
For the record, and in compliance with the provisions of the Amended Decree of the Supreme Court of the United States entered June 7, 1954, I hereby transmit the 62nd Annual Report of the River Master of the Delaware River for the 12-month period from December 1, 2014, to November 30, 2015. In this report, this period is referred to as the River Master “report year.”
During the 2015 River Master report year, monthly precipitation in the upper Delaware River Basin ranged from 49 percent of the long-term average in May 2015 to 184 percent of the long-term average in June 2015. Precipitation from December to May, when reservoirs typically refill, was 14.23 inches. Precipitation was below normal in December, January, February, March, April, May, August, and November and above normal in the other 4 months.
When the report year began on December 1, 2014, combined useable storage in the New York City reservoirs in the upper Delaware River Basin was 154.457 billion gallons or 57 percent of combined storage capacity. The reservoirs were at 94.9 percent of usable capacity on May 31, 2015. Combined storage remained high (above 80 percent combined capacity) through late August 2015. The combined usable storage was 193.239 billion gallons at the end of the report year on November 30, 2015. During the report year, operations in the basin were conducted as stipulated by the Decree and the Flexible Flow Management Program (FFMP).
On July 13, 2015, the Delaware River Master Advisory Committee (Advisory Committee) met at the U.S. Geological Survey (USGS) New Jersey Water Science Center in Lawrenceville, New Jersey, to discuss the issues related to water use in the Delaware River Basin, safe yield, and Excess Release Quantity. The meeting adjourned early due to an emergency at Cannonsville Reservoir (where a major leakage was reported). During the report year, the following individuals served as members of the Advisory Committee:
During the report year, the River Master and staff participated in many water-supply related meetings of the Delaware River Basin Commission (DRBC). The Deputy Delaware River Master met periodically with representatives of the Decree Parties as a member of the Decree Parties Work Group and the DRBC’s Regulated Flow Advisory Committee. In addition to the management of reservoir releases and streamflow in the upper Delaware River Basin, an issue of particular interest to the River Master was the impending expiration of the current FFMP on June 1, 2015.
River Master operations were executed through the USGS Office of the Delaware River Master (ODRM) located at Milford, Pennsylvania. Marie Owens (Hynes), Deputy Delaware River Master, continued in charge of the office, assisted by hydrologist Vincent DiFrenna.
During the report year, the ODRM continued the weekly distribution of a summary hydrologic report. These reports contain provisional data on precipitation in the upper Delaware River Basin, releases and spills from New York City reservoirs to the Delaware River, diversions to the New York City water supply system, reservoir contents, the daily segregation of the flow of the Delaware River at the USGS Montague, New Jersey, gaging station, and diversions by New Jersey. The reports were distributed to members of the Advisory Committee and other parties interested in Delaware River operations. A monthly summary of hydrologic conditions was also provided to Advisory Committee members. The weekly and monthly hydrologic reports are available through the ODRM website (https://webapps.usgs.gov/odrm/data/data.html).
The first section of this report documents Delaware River operations during the report year. New York City diverted 184.722 billion gallons from the Delaware River Basin and released 94.972 billion gallons from the Pepacton, Cannonsville, and Neversink Reservoirs to the Delaware River for conservation purposes during the report year. A total of 4.219 billion gallons was spilled from the Pepacton, Cannonsville, and Neversink Reservoirs. The ODRM directed releases from these reservoirs to the Delaware River that totaled 38.129 billion gallons. The second section of this report describes water quality at various monitoring sites on the Delaware River estuary. The section includes basic data on chemical properties and physical characteristics of the water and presents summary statistics.
Throughout the year, diversions to New York City’s water supply system and releases designed to maintain the flow of the Delaware River at Montague, New Jersey, were made as directed by the ODRM. Diversions by New York City from its reservoirs in the Delaware River Basin did not exceed the limit stipulated by the Decree. Diversions by New Jersey were also within stipulated limits.
The River Master and staff are grateful for the continued cooperation and support of the Decree Parties. Also, the contributions of the PPL Corporation, the Talen Energy Corporation, and Eagle Creek Renewable Energy, LLC, in informing the ODRM of plans for power generation and providing data on the reservoir releases and elevations are greatly appreciated.
Sincerely yours,
/Signed/
Kendra Russell, P.E.
Delaware River Master
Executive Summary
A Decree of the Supreme Court of the United States, entered June 7, 1954 (New Jersey v. New York, 347 U.S. 995), established the position of Delaware River Master within the U.S. Geological Survey. In addition, the Decree authorizes the diversion of water from the Delaware River Basin and requires compensating releases from specific reservoirs owned by New York City be made under the supervision and direction of the River Master. The Decree stipulates that the River Master provide reports to the Court, not less frequently than annually. This report is the 62nd annual report of the River Master of the Delaware River. This report covers the 2015 River Master report year, which is the period from December 1, 2014, to November 30, 2015.
During the report year, precipitation in the upper Delaware River Basin was 42.22 inches or 95 percent of the long-term average. The combined storage remained above 80 percent of the combined capacity until August 2015. The lowest combined storage of the report year was 57 percent of the total combined capacity on December 1, 2014. Delaware River Master operations during the year were conducted as stipulated by the Decree and the Flexible Flow Management Program.
Diversions from the Delaware River Basin by New York City and New Jersey fully complied with the Decree. The reservoir releases were made as directed by the River Master at rates designed to meet the flow objective for the Delaware River at Montague, New Jersey, on 72 days during the report year. Interim Excess Release Quantity and conservation releases, designed to relieve thermal stress and protect the fishery and aquatic habitat in the tailwaters of the reservoirs, were also made during the report year.
Water quality in the Delaware River estuary between the streamgages at Trenton, New Jersey, and Reedy Island Jetty, Delaware, was monitored at several locations. Data on water temperature, specific conductance, dissolved oxygen, and pH were collected continuously by electronic instruments at four sites.
Introduction
An amended Decree of the Supreme Court of the United States, entered June 7, 1954 (New Jersey v. New York, 347 U.S. 995; available at https://webapps.usgs.gov/odrm/about/decree), which superseded a 1931 Decree, authorizes diversion of water from the Delaware River Basin and provides for releases of water from three New York City reservoirs—Pepacton, Cannonsville, and Neversink—to the upper Delaware River. The Decree stipulates that these diversions and releases are to be made under the supervision and direction of the Office of the Delaware River Master (ODRM). The Decree also stipulates that reports on Delaware River operations be made to the Court not less frequently than annually. The reports can be accessed at https://webapps.usgs.gov/odrm/publications/publications.
This report documents operations from December 1, 2014, to November 30, 2015—the 2015 River Master report year—hereafter referred to as the “report year.” This report also presents information on the quality of water in the Delaware River estuary during the report year.
Since 2007, the Decree Parties (Delaware, New Jersey, New York, New York City, and Pennsylvania) have unanimously approved a series of Flexible Flow Management Program (FFMP) agreements (available at https://webapps.usgs.gov/odrm/ffmp/flexible-flow-management-program) to manage the shared waters of the Delaware River Basin (appendix 1). The 2014 FFMP and 2015 FFMP were in effect during the 2015 River Master report year: “The current FFMP is also an extension of the June 1, 2011, Agreement and incorporates the edits from the previous three extensions of the 2011 Agreement with no additional program modifications other than dates. This Agreement, the 2015 FFMP, shall be effective from June 1, 2015, to May 31, 2016.” (appendix 1; also available at https://webapps.usgs.gov/odrm/documents/ffmp/FFMP_2015_Agreement1.pdf).
During this period, an additional agreement was signed to temporarily modify storage calculations related to a drought watch. As part of that agreement, one-half of the snow-water-equivalent was added to the actual combined storage in the New York City reservoirs to determine when storage conditions were assessed to enter zone L3 from March 13 through April 15, 2015 (appendix 2; also available at https://webapps.usgs.gov/odrm/documents/ffmp/2015_Temporary_Modification.pdf).
Some hydrologic data presented in this report are streamflow and water quality records for U.S. Geological Survey (USGS) water-quality streamgages. The USGS collected and computed these records in cooperation with the States of New York and New Jersey, the Commonwealth of Pennsylvania, and the City of New York. The locations of major streams and reservoirs, and selected USGS streamgages in the Delaware River Basin, are shown in figure 1.
Map showing Delaware River Basin upstream from Wilmington, Delaware. The Delaware River Basin boundary is shown along with “key gaging stations” and “index gaging stations;” refer to the “Glossary” section for definitions.
Method to Determine Directed Releases From New York City Reservoirs
The data and computations of the streamflow components form the basic operational record used by the ODRM to carry out specific responsibilities related to the Montague flow objective. The operational record has two parts: (1) segregating the streamflow components of the current daily mean discharge at the USGS streamgage on the Delaware River at Montague, New Jersey (N.J.) (site number 01438500), to compute the uncontrolled runoff; and (2) forecasting the uncontrolled runoff and using forecasted information from other sources to predict the flow at the Montague site with adequate advance time to direct releases. The forecasting process is used to determine whether the ODRM directs New York City reservoirs to release water to maintain, at a minimum, the Montague flow objective at the USGS streamgage at Montague, N.J., which is defined in table 1 of appendix 1.
Segregating Streamflow Components—Delaware River at Montague, New Jersey
The segregation of streamflow at the Montague site involves determining the flow components, including releases from the New York City reservoirs, releases from Lake Wallenpaupack and Rio Reservoir for generation of hydroelectric power, and uncontrolled runoff. For the segregation of components of daily mean flow at the Montague site, the following data are used:
-
1. controlled releases from the Pepacton, Cannonsville, and Neversink Reservoirs of New York City;
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2. controlled releases from Lake Wallenpaupack on Wallenpaupack Creek to produce hydroelectric power; and
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3. controlled releases from Rio Reservoir on the Mongaup River to produce hydroelectric power.
To determine the contributions of each of these releases, the amount of time it takes the water to travel from the release point to the Montague site is required. The various traveltimes are used to determine the appropriate time-delayed flow contributions from the previously noted sources. The time-adjusted controlled flows of the above sources are subtracted from the total streamflow measured at the Montague site to determine the uncontrolled runoff (including reservoir spills and groundwater) from the drainage area upstream from the Montague site.
Traveltimes were computed from reservoir and powerplant operations data and historical streamflow records. The traveltimes are adequate for ODRM operations. Occasionally, however, significant exceptions are observed. For example, during a large increase in a directed release from the Cannonsville Reservoir, the arrival time of the water at the Montague site can be delayed as long as 1.5 days because a substantial amount of water must fill the channel before a steady flow arrives at the Montague site. During winter, ice formation and lower streamflow gradually increase the resistance to water flow, resulting in increased traveltimes. Because ice-affected traveltimes increase gradually over several days and releases were not directed to meet the Montague flow objective during periods of ice, no adjustments were made to compensate for increased traveltimes during these periods of the report year. The following list gives the average times for the effective travel of water from the various sources of controlled supply to the Montague site. These traveltimes, in hours, were used for flow routing during the 2015 report year: Pepacton Reservoir, 60; Cannonsville Reservoir, 48; Neversink Reservoir, 33; Lake Wallenpaupack, 16; and Rio Reservoir, 8.
Forecasting Streamflow—Delaware River at Montague, New Jersey
The releases from New York City’s reservoirs necessary to meet the Montague flow objective were computed based on the forecasted streamflow at the Montague site, exclusive of releases from New York City’s Delaware River Basin reservoirs. The flow must be forecast 3 days in advance to account for the longest traveltime needed for the flow to reach the Montague site from the New York City reservoirs.
The electric utilities PPL Corporation and Eagle Creek Renewable Energy, LLC, provided daily forecasts of power generation and releases to the Delaware River from Lake Wallenpaupack and Rio Reservoir, respectively, to the ODRM. Because the hydroelectric powerplants were primarily used for meeting rapidly varying peak-power demands, the forecasts were subject to various modifying factors, including the vagaries of weather on electricity demand. In addition, because the power companies are members of regional transmission organizations, demand for power outside the local service area can unexpectedly affect generation schedules. Consequently, at times, the actual use of water for power generation differs considerably from the forecasts used in the design of reservoir releases.
For computational purposes during periods of low flow, estimates of uncontrolled runoff at the Montague site were treated as having two components: (1) current runoff and (2) forecasted runoff from precipitation.
An estimate of uncontrolled runoff was computed using a recession procedure. A recession curve of uncontrolled inputs was developed using the discharge at the Montague site and was used to forecast the uncontrolled portion of flow at Montague, N.J., 3 days in advance.
Forecasted runoff was determined from data provided by the National Weather Service office in Binghamton, New York (N.Y.), which included quantitative forecasts of average precipitation and air temperatures for the 3,480-square-mile (mi2) drainage basin upstream from Montague, N.J. During winter, runoff was estimated based on the status of snow and ice, along with forecasted precipitation and temperature. During other periods, forecasted precipitation was used to estimate runoff.
The forecasted flow at the Montague site, exclusive of releases from New York City’s Delaware River Basin reservoirs, is computed as the sum of forecast releases from hydroelectric powerplant reservoirs, estimated uncontrolled runoff—including conservation releases from Rio Reservoir—and estimated runoff from predicted rainfall. Each of these inputs is adjusted for traveltime. If the computed total flow is less than the Montague flow objective, the deficiency is made up by using releases from New York City’s reservoirs, as directed by the ODRM.
Based on the previous day’s provisional data, a balancing adjustment is applied to the following day’s release design. The balancing adjustment is computed as 10 percent of the difference between the cumulative directed release and the cumulative directed release required for exact forecasting and is limited to a maximum of 50 cubic feet per second (ft3/s) magnitude. The balancing adjustment calls for more water to be released when previous directed releases (or lack of releases) were insufficient to meet the Montague flow objective. The adjustment calls for less water to be released when previous directed releases were higher than required to meet the Montague flow objective.
When updated forecasts of precipitation or powerplant releases showed appreciable changes after a release was directed, the release required from New York City’s reservoirs was recomputed based on the updated forecasts. Commonly, this procedure resulted in a reduced release requirement for New York City reservoirs on that day. Only final values for releases from New York City reservoirs are presented in this report.
Hydrologic Conditions
Precipitation
The sum of average monthly precipitation in the Delaware River Basin upstream from Montague, N.J., was 42.22 inches (in.) during the 2015 report year and was 95 percent of the long-term (74-year) average (table 1, in back of report). Monthly precipitation ranged from 49 percent of the long-term average in May 2015 to 184 percent of the long-term average in June 2015 (table 1). Precipitation data for the 2015 report year were computed from records from 10 geographically distributed stations operated by the National Weather Service, the New York City Department of Environmental Protection’s (NYCDEP) Bureau of Water Supply, and the ODRM.
The seasonal period from December to May is typically when surface-water and groundwater reservoirs refill. During this period in 2014–15, total precipitation was 14.23 in., which is about 69 percent of the 74-year long-term average. During the June–November period, total precipitation was 27.99 in., which is 117 percent of the 74-year long-term average.
Reservoir Storage
Table 2 summarizes the “point of maximum depletion” and other pertinent levels and the contents of the Pepacton, Cannonsville, and Neversink Reservoirs. The NYCDEP provided this information.
Daily storage in the Pepacton, Cannonsville, and Neversink Reservoirs above the point of maximum depletion, or minimum full-operating level, is given in tables 3, 4, and 5 (all in back of report), respectively, and the combined storage during the report year is shown in figure 2. On December 1, 2014, combined useable storage in the three reservoirs was 154.457 billion gallons or 57 percent of combined capacity. From December to May, the inflow to the New York City reservoirs typically exceeds the outflow, and, consequently, storage increases. Combined storage increased during the report year, and the reservoirs were at about 94.9 percent of usable capacity on May 31, 2015. Combined storage remained high (above 80 percent of combined capacity) until August 2015. The lowest combined storage was 154.457 billion gallons (57 percent) on December 1, 2014.
The three reservoirs spilled a total of 4.219 billion gallons when reservoirs reached maximum capacity during the year. The Pepacton Reservoir spilled from June 30, 2015, to July 3, 2015. The Cannonsville Reservoir spilled during the following periods: April 24–May 2, 2015, and July 1–7, 2015. The Neversink Reservoir spilled from June 27 to July 3, 2015. Combined storage reached a maximum for the report year on July 3, 2015, at 273.215 billion gallons. The reservoirs’ storage decreased from this point and the combined storage was 193.239 billion gallons or 71.3 percent of combined capacity on November 30, 2015.
Table 2.
Elevation and capacities of structures of the Pepacton, Cannonsville, and Neversink Reservoirs.[ft, foot; Mgal, million gallons; NA, not available; —, not applicable]
Graph showing rule curves and actual contents for three New York City reservoirs—Cannonsville, Neversink, and Pepacton—in the Delaware River Basin from December 1, 2014, to November 30, 2015. The full capacity usable-storage line and the five conservation release rate zones (L1–5) are shown. The conservation release rate zones are defined in the “conservation releases” definition in the “Glossary” section.
Operations
Operations for December 1, 2014–November 30, 2015, were conducted as described in the FFMP (revised, effective June 1, 2014, and continued for a second year, effective June 1, 2015). The allowable diversion to New York City was 800 million gallons per day (Mgal/d) throughout the year. The Montague flow objective was 1,750 ft3/s. The allowable diversion to New Jersey was 100 Mgal/d.
Conservation releases from the New York City reservoirs were made at the rates shown in 2014 FFMP tables 4a–g (https://webapps.usgs.gov/odrm/ffmp/FFMP_2014_Agreement.pdf) and the June 1, 2015, FFMP (appendix 1), including table 4e of both FFMPs in December, table 4d in mid-January, table 4a in late January, table 4f in mid-February, table 4g in late February, table 4a in early March–May, table 4b in early June, table 4e in mid-June, tables 4f and 4g in late June–August, table 4g in September, and tables 4f and 4g in October–November 2015 (see “Archived OST [Operational Support Tool] Summary Data” at https://webapps.usgs.gov/odrm/data/data.html).
Diversions to New York City Water Supply
The 1954 amended Decree authorizes New York City to divert water from the Delaware River Basin at a rate not to exceed the equivalent of 800 Mgal/d. The Decree specifies that the diversion rate shall be computed as the aggregate total diversion beginning June 1 of each year divided by the total number of days elapsed since the preceding May 31.
Records of daily diversions through the East Delaware, West Delaware, and Neversink Tunnels (fig. 1) were provided to the ODRM by the NYCDEP. These records were obtained from the City’s calibrated instruments, which are connected to Venturi meters installed in the tunnel conduits. The measured flows were transmitted electronically on a 15-second interval to New York City computers, and 5-minute interval release and diversion quantities for the preceding 5-minute period were computed using the instantaneous rate-of-flow data from each instrument. These 5-minute quantities were then summed to compute daily total flows, which were reported daily to the ODRM. Each week, the computed diversion values were checked against the flow-meter totalizer readings by the NYCDEP and corrected when necessary.
Daily diversions during the report year from the Pepacton, Cannonsville, and Neversink Reservoirs to the New York City water supply system (Rondout Reservoir) are given in table 6 (in back of report). A running account of the average rates of combined diversions from the three reservoirs beginning June 1, 2014, computed as stipulated by the Decree, is also shown in table 6. A total of 184.722 billion gallons of water were diverted to the New York City water supply system during the report year with an average of 506 Mgal/d, which is below the maximum diversion rate. The maximum daily diversion from a single reservoir was 501 million gallons (Mgal) on June 27 and 28, 2015, from the Pepacton Reservoir through the East Delaware Tunnel. The maximum daily combined diversion from all three reservoirs was 978 Mgal on January 26, 2015. Diversions by New York City did not exceed the limits stipulated by the Decree and the FFMP. Data on water consumption by New York City, for each calendar year since 1950, from all sources of supply, are presented in table 7 (in back of report).
The East Delaware Tunnel is used to divert water from Pepacton Reservoir to Rondout Reservoir. The hydroelectric powerplant at the downstream end of the East Delaware Tunnel operated for most days of the report year. When the powerplant was not in operation, water leaked through the wicket gates that was not recorded by the totalizer. A current-meter measurement made in 1989 showed that the (assumed constant) rate of leakage is about 12.4 ft3/s (8.0 Mgal/d). Because the powerplant was not in operation for the equivalent of 98 days during the 2015 report year, the estimated quantity of unmeasured leakage (diverted but not recorded) was about 0.8 billion gallons.
The West Delaware Tunnel is used to divert water from the Cannonsville Reservoir to Rondout Reservoir. Inspections of the channel below the outlet, when the valves were closed, revealed negligible leakage. A hydroelectric powerplant uses water diverted through the West Delaware Tunnel, but the plant operates only when diversions are less than 300 Mgal/d. When the powerplant is not operating, the valves on the pipelines to the plant are closed, and there is no leakage through the system.
The Neversink Tunnel is used to divert water from Neversink Reservoir to Rondout Reservoir. A hydroelectric powerplant uses water diverted through the Neversink Tunnel. When the powerplant is not operating and the main valve on the diversion tunnel is open, leakage develops that is not recorded by the Venturi instruments. One current-meter measurement made in 1999 showed a leakage rate of 16.2 ft3/s (10.5 Mgal/d). The leakage is included in the recorded flow when the powerplant is operating. No leakage occurs when the main valve on the tunnel is closed. During the 2015 report year, the powerplant operated part of the day on most days and was not operated for the equivalent of 225 days. About 2.4 billion gallons of water were diverted but not recorded, according to the leakage rate noted previously (16.2 ft3/s [10.5 Mgal/d]) and powerplant records.
Diversions by New Jersey
The Decree authorizes New Jersey to divert water from the Delaware River and its tributaries in New Jersey to areas outside of the Delaware River Basin without compensating releases. Under the FFMP, New Jersey diversions shall not exceed 100 Mgal/d as a monthly average, and the daily mean diversion shall not exceed 120 Mgal/d. When the lower part of the Delaware River Basin is in a drought warning period, diversions shall not exceed 85 Mgal/d as a running average.
The USGS streamgage on the Delaware and Raritan Canal at Port Mercer, N.J. (USGS site number 01460440; fig. 1), is used as the official control point for measuring these diversions by New Jersey. Based on data collected by the USGS at this site, the maximum average monthly diversion was 97 Mgal/d during November 2015 (table 8, in back of report) (USGS, 2019e). The maximum daily mean diversion was 111 Mgal/d on January 24, 2015 (table 8). Diversions by New Jersey did not exceed the limits stipulated by the FFMP.
Montague Flow Objective
The components of forecasted flow at the Montague site during low flow (forecasted releases from power reservoirs, estimated uncontrolled runoff including conservation releases from the Rio Reservoir, and forecasted increase in runoff from precipitation) and the sums of flows exclusive of releases from New York City’s reservoirs are given in table 9 (in back of report). If the computed sum of the components is less than the flow objective at the Montague site, then the deficiency is made up by using releases from New York City’s reservoirs, as directed by the ODRM. Table 10 (in back of report) presents the ODRM daily operations record of reservoir releases and the segregation of the various components contributing to the flow of the Delaware River at the Montague site.
The forecasted flow of the Delaware River at the Montague site, based on provisional data and exclusive of water released from the New York City reservoirs, was greater than the flow objective on all days from December 1, 2014, to May 12, 2015, and no releases were directed. The observed daily mean discharge at the Montague site was greater than the applicable flow objective (1,750 ft3/s) on all days except for 1 day in May, 8 days in September, and 3 days in October (table 11, in back of report) (USGS, 2019d).
The forecasted flow at the Montague site, exclusive of water released from the New York City reservoirs, was less than the flow objective on 73 days between May 13, 2015, and October 30, 2015, and directed releases were required (table 9). For 11 days, from May 15, 2015, to October 24, 2015, the observed flow at the Montague site was less than the flow objective (table 11). Of those observed daily flows, 10 were within 10 percent of the flow objective, whereas the daily mean flow on September 12, 2015, was 1,546 ft3/s, which is 88.3 percent of the flow objective (table 11).
The components of total flow observed at the Montague site from May 15 to 30, 2015, and from July 28 to October 27, 2015, are shown in figure 3. The flow is segregated into the portion derived from the New York City reservoirs, the portion contributed by the power reservoirs, and the uncontrolled runoff from the drainage area below the reservoirs. As described previously, the uncontrolled runoff was computed as the residual of observed flow minus releases and was subject to errors in observations, transit times, and routings of the flow components. The conservation release from Rio Reservoir is included in the uncontrolled runoff component. The effect of these uncertainties is incorporated into the computation of uncontrolled runoff.
Graphs showing flow components—uncontrolled runoff, powerplant reservoirs, and New York City reservoirs—for the Delaware River at Montague, New Jersey (A) from May 15 to 30, 2015, and (B) from July 28 to October 31, 2015. The Montague flow objective is also shown.
Excess Release Quantity and Interim Excess Release Quantity
Per sections 4b and c of the 2015 FFMP (appendix 1), the Excess Release Quantity supports the Interim Excess Release Quantity (IERQ). The IERQ is 10.0 billion gallons (15,468 cubic feet per second accumulated daily ([ft3/s]-d).1 The 2015 FFMP specifies that 3.91 billion gallons (6,045 [ft3/s]-d) of the IERQ is incorporated into the releases tables to enhance base releases from New York City’s Delaware River Basin reservoirs. The remaining IERQ balance of 6.09 billion gallons (9,423 [ft3/s]-d) is reserved and may be used for additional releases to meet the Trenton equivalent flow objective or establish an Extraordinary Needs Bank as provided for in section 4d of the 2015 FFMP (appendix 1). Per section 4c of the 2015 FFMP, upon request by the “Lower Basin States" or the Delaware River Basin Commission (DRBC), New York City is required to release water in sufficient quantities from the remaining IERQ balance to maintain a flow in the Delaware River at Trenton, N.J. (USGS site number 01463500), of 3,000 ft3/s during basinwide normal conditions from June 15 through March 15 (known as the seasonal period). The maximum amount of water required for release from the remaining IERQ in any seasonal period is 70 billion gallons. New York City is required to make releases from the IERQ until May 31, 2016, or until the aggregate quantity of the IERQ is exhausted, whichever occurs first.
In this report, the descriptor “cubic feet per second accumulated daily” is used to explain the measure [(ft3/s)-d]. See the “Supplemental Information” section for clarification.
As described in section 4d of the 2015 FFMP (appendix 1), the DRBC and the ODRM may at any time review extraordinary water needs to support such research, aquatic life, or other water-use activity as may be approved by the DRBC. Upon unanimous agreement, the Decree Parties may bank all or a portion of the IERQ remaining in an IERQ Extraordinary Needs Bank that can provide for such extraordinary water needs. Banked quantities are deducted from the IERQ, and unused Extraordinary Needs Bank water is returned to the IERQ.
In 2015, 100 (ft3/s)-d of IERQ water was requested on September 17, to be released for September 20; and on September 18, to be released for September 21, to maintain flows at the Trenton site (table 10). The request for September 21was cancelled, and that water was not released. The unused portion of the IERQ Extraordinary Needs Bank was restored to the annual IERQ balance to maintain the flow target at the Trenton site.
Tailwaters Habitat Protection and Discharge Mitigation Program
The FFMP established a Tailwaters Habitat Protection and Discharge Mitigation Program, which consists of (1) conservation releases designed to protect the ecology in the tailwaters below the New York City reservoirs and (2) discharge mitigation releases designed to help mitigate the effects of water spilling from the full Delaware River Basin reservoirs. Controlled releases were made from the New York City Delaware River Basin reservoirs. From December 1, 2014, to November 30, 2015, 94.972 billion gallons was released from the New York City Delaware River Basin reservoirs under the Tailwaters Habitat Protection and Discharge Mitigation Program.
Comparison of River Master Operations Data With Other Records
ODRM operations are conducted on a daily basis and, by necessity, use preliminary streamflow data. This section compares records used in ODRM operations with final data published for selected USGS streamgages. Data on releases were reported in million gallons per day and converted to cubic feet per second for comparisons.
Analysis of Forecasts
Forecasts of streamflow at the Montague site, based on anticipated contributions from the flow components described previously but excluding releases from the New York City reservoirs, differed from the observed flow on most days. Occasionally, variations in the components were partially compensating, and observed flows compared favorably with forecasted flows.
The forecasted flow of the Delaware River at Montague, N.J., exclusive of releases from the New York City reservoirs, was less than the flow objective on 7 days in the second half of May and on most days from late July through late October 2015 (table 9), as indicated by directed releases being made. Table 12 compares forecasted and actual flow from hydroelectric powerplant releases and uncontrolled runoff from May 13 to 31 and from July 28 to October 31, 2015.
Table 12.
Cumulative forecasted and actual release volumes from Lake Wallenpaupack, Rio Reservoir, and uncontrolled runoff from May 13 to 31, 2015, and from July 28 to October 31, 2015.[(ft3/s)-d, cubic foot per second accumulated by daily]
For the May 13–31, and July 28–October 31, 2015, periods shown in table 12, actual releases from Lake Wallenpaupack and Rio Reservoir averaged 7.1 and 64 percent more than the forecasted releases, respectively. Powerplant forecasted volumes were calculated using columns 1 and 2 in table 9; powerplant actual releases were calculated using columns 5 and 6 in table 10. Observed runoff (column 10 of table 10) from the uncontrolled area was about 10 percent more than forecasted runoff (columns 3 + 4 in table 9).
Forecasted and actual releases from Lake Wallenpaupack and Rio Reservoir can differ considerably on any given day. The differences between actual and forecasted daily releases from May 13 to 31, 2015, and July 28 to October 31, 2015, are as follows: daily releases at Lake Wallenpaupack varied by 230 ft3/s less than forecasted releases to 292 ft3/s greater than forecasted releases, and daily releases at Rio Reservoir varied by 124 ft3/s less than forecasted releases to 230 ft3/s greater than forecasted releases. Based on measured streamflow at the Montague site, total directed releases from the New York City reservoirs during the report year (column 9 of table 9) were about 6.0 percent more than required for exact forecasting (column 11 of table 9).
A comparison of forecasted and computed runoff hydrographs from the uncontrolled area (fig. 4) indicate that the forecasts were suitable for use in designing releases from the New York City Delaware River Basin reservoirs. Numerical adjustments to the designs were made when needed to compensate for forecasting errors. However, because of traveltimes, the effects of the adjustments on flows at the Montague site were not evident until several days after the design date.
Hydrographs of computed and forecasted uncontrolled runoff components, Delaware River at Montague, New Jersey, from July 7 to October 31, 2015. Discharge is shown in cubic feet per second.
Releases From New York City Reservoirs
The ODRM operations data on controlled releases from the Pepacton, Cannonsville, and Neversink Reservoirs to the Delaware River were provided by the NYCDEP for the ODRM. These data were collected from calibrated instruments connected to Venturi meters installed in the outlet conduits of the reservoirs.
The USGS streamgage on the East Branch Delaware River at Downsville, N.Y. (USGS site number 01417000; fig. 1), is 0.5 miles (mi) downstream from Downsville Dam. Discharge measured at this site includes releases from the Pepacton Reservoir and a small amount of seepage and any runoff that enters the channel between the dam and the site. The drainage area is 371 mi2 at the dam and 372 mi2 at the site. The streamgage records are rated “good,” which means that about 95 percent of the measured daily mean discharges are within 10 percent of the actual discharge.
Figure 5A shows the measured flow from Pepacton Reservoir, including spillway, conservation, and directed releases, as reported by New York City, compared with the records for the USGS streamgage on East Branch Delaware River at Downsville, N.Y. (table 13, in back of report), from December 1, 2014, to November 30, 2015 (USGS, 2019a). The average difference is 5.9 percent, and 95 percent of the daily differences between the streamgage readings and New York City records are less than 14 percent. Greater differences rarely occur and can be due to rainfall. The instruments connected to the Venturi meters were recalibrated periodically by New York City to improve the accuracy of the recorded flow data.
The USGS streamgage on the West Branch Delaware River at Stilesville, N.Y. (USGS site number 01425000; fig. 1), is 1.4 mi downstream from the Cannonsville Dam. Discharge measured at this site includes releases from the Cannonsville Reservoir and runoff from the 2 mi2 of drainage area between the dam and the site. The drainage area is 454 mi2 at the dam and 456 mi2 at the site. The streamgage records are rated “fair,” which means that about 95 percent of the daily mean discharges are within 15 percent of the actual discharge. The records include runoff from the area between the dam and the site and seepage near the base of the dam.
Figure 5B shows releases from Cannonsville Reservoir (including spillway, conservation, and directed releases) reported by New York City compared with records for the USGS streamgage on the West Branch Delaware River at Stilesville, N.Y. (site number 01425000) (table 14, in back of report), from December 1, 2014, to November 30, 2015 (USGS, 2019b). The mean difference is 10.3 percent; 95 percent of the daily differences between the streamgage readings and New York City records are less than 31.4 percent. The greatest differences between the measured flows are primarily at lower flow rates.
The USGS streamgage on Neversink River at Neversink, N.Y. (site number 01436000), is 1,650 feet (ft) downstream from Neversink Dam (fig. 1). Discharge measured at this site includes releases from the Neversink Reservoir and, during storms, a small amount of runoff that originates between the dam and the site. The drainage area is 92.5 mi2 at the dam and 92.6 mi2 at the site. The streamgage records are rated “good,” which means that about 95 percent of the measured daily mean discharges are within 10 percent of the actual discharge.
Figure 5C shows releases from Neversink Reservoir, including spillway, conservation, and directed releases, as reported by New York City, compared with the records for the USGS streamgage on the Neversink River at Neversink, N.Y. (table 15, in back of report), from December 1, 2014, to November 30, 2015 (USGS, 2019c). The mean difference between the released flow and measured flow is 2.9 percent, and 95 percent of the daily differences between the streamgage readings and New York City records are less than 7 percent.
Delaware River at Montague, New Jersey
The ODRM’s operations record for the Delaware River at Montague, N.J., site (table 10) showed 2 percent more discharge for the report year than the published USGS record for the streamgage (table 11). Daily values for the two records agreed closely, except during ice-affected periods and the summer vegetation growth season.
Conformance of Operations Under the Amended Decree of the Supreme Court of the United States Entered June 7, 1954
From December 1, 2014, to November 30, 2015, operations of the ODRM were conducted as stipulated by the Decree and the FFMP. Diversions from the Delaware River Basin to the New York City water supply system did not exceed those authorized by the Decree and the FFMP. New York City released water from its reservoirs at rates directed by the ODRM to meet the applicable Montague flow objective. During the report year, New York City complied fully with all directives and requests of the ODRM. Diversions from the Delaware River Basin by New Jersey were within the limits stipulated by the Decree. New Jersey complied fully with all directives and requests of the ODRM. The IERQ was used in accordance with the FFMP and agreements completed throughout the report year.
Graphs showing New York City-measured mean flow compared with computed mean flow records of U.S. Geological Survey (USGS) gaging stations downstream from their respective reservoirs: (A) East Branch Delaware River at Downsville, New York (N.Y.) (USGS site number 01417000), downstream from Pepacton Reservoir (data from USGS, 2019a); (B) West Branch Delaware River at Stilesville, N.Y. (USGS site number 01425000), downstream from Cannonsville Reservoir (data from USGS, 2019b); and (C) Neversink River at Neversink, N.Y. (USGS site number 01436000), downstream from Neversink Reservoir, December 1, 2014–November 30, 2015 (data from USGS, 2019c).
Quality of Water in the Delaware River Estuary
This section describes water-quality monitoring programs for the Delaware River estuary during the 2015 report year. Selected data are presented, and water-quality conditions are summarized.
Water-Quality Monitoring Programs
U.S. Geological Survey Continuous Water-Quality Monitoring Program
As part of a long-term program, in cooperation with the DRBC, the USGS operates continuous water-quality monitors at four locations in the Delaware River estuary between the streamgages at Trenton, N.J., and Reedy Island Jetty, Delaware (Del.) (fig. 6).
Continuous water temperature, specific conductance, dissolved oxygen, and pH data were collected at four sites: Delaware River at Trenton, N.J. (USGS site number 01463500); Delaware River at Benjamin Franklin Bridge at Philadelphia, Pennsylvania (Pa.) (USGS site number 01467200); Delaware River at Chester, Pa. (USGS site number 01477050); and Delaware River at Reedy Island Jetty, Del. (USGS site number 01482800). Continuous turbidity data were also collected at the Trenton and Reedy Island Jetty sites. The DRBC and others use these data to assess water-quality conditions and track the “salt front” movement in the Delaware River estuary. Continuous-monitor data are processed and stored in the USGS National Water Information System database (NWIS; https://waterdata.usgs.gov/nwis). Selected monitoring data from the 2015 report year are included in this section of the report.
For this report, USGS site number 01467200 is referred to as “Delaware River at Benjamin Franklin Bridge at Philadelphia, Pa.” because that was the gage name during the report period from December 1, 2014, to November 30, 2015. The gage was moved 150 ft upstream and renamed “Delaware River at Penns Landing, Philadelphia, Pa.” in January 2020. The updated name is used in the “References Cited” section to refer to the data as listed on NWIS web at the time of publication.
Delaware River Estuary Boat Run Monitoring Program
Each year, the DBRC contracts with the Delaware Department of Natural Resources and Environmental Control to collect water samples at 22 sites on the Delaware River estuary (fig. 6; sites A–N, P–W) (DRBC, 2022). Samples are collected once a month from April to October. The goals of this program are to provide accurate, precise, and defensible estimates of the surface-water quality of the Delaware River estuary and allow for an assessment of compliance with water-quality criteria. Sample analysis includes routine and bacterial parameters, nutrients, heavy metals, chlorophyll-a, dissolved silica, and volatile organics. Water-quality data for these DBRC sampling sites are not presented in this report but are accessible from the DRBC Delaware Estuary Water Quality (Boat Run) Explorer (https://www.nj.gov/drbc/programs/quality/boat-run_explorer-app.html).
Water Quality During the 2015 Report Year
Streamflow
Streamflow has a major effect on the water quality of the Delaware River estuary. Large freshwater inflows commonly result in improved water quality by limiting the upstream movement of seawater and reducing the concentration of dissolved substances. High inflows help maintain lower water temperatures during warm weather and support higher concentrations of dissolved oxygen. Under certain conditions, however, high streamflows can transport large quantities of nutrients to the estuary, which can result in excessive algae levels.
Streamflow from the Delaware River Basin upstream from the Trenton, N.J., site is the primary source of freshwater inflow to the Delaware River estuary. During the report year, monthly average streamflow measured at the Delaware River at Trenton, N.J., streamgage (USGS site number 01463500) was highest during April 2015 (19,563 ft3/s) and lowest during September 2015 (4,152 ft3/s; table 16, in back of report). Long-term monthly mean streamflow was computed for October 1912 through November 2014 (USGS, 2019f). Monthly mean streamflows were less than the long-term mean monthly streamflows from December 2014 through May 2015 and from August through November 2015. The greatest percentage of flow deficiency was in February 2015, when the monthly mean streamflow was 31 percent of the long-term mean monthly flow. The highest daily mean streamflow during the report year was 39,800 ft3/s on July 2, 2015, and the lowest was 3,090 ft3/s on October 25, 2015 (table 16).
Map showing location of Delaware River Basin Commission (DRBC) water-quality monitoring sites on the Delaware River estuary. Modified from DRBC (2022). U.S. Geological Survey streamgaging sites (1–4) and DRBC sampling sites (A–N, P–W) are listed.
Water Temperature
Water temperature has an important influence on water quality, as it affects various physical, chemical, and biological properties of water (USGS, 2020c). Generally, increases in water temperature have detrimental effects on water quality by decreasing the saturation level of dissolved oxygen and increasing the biological activity of aquatic organisms. Although the primary factors that affect water temperature in the Delaware River estuary are climatic, various kinds of water-use, especially powerplant cooling, can also have substantial effects.
Water temperature monitoring data for the Benjamin Franklin Bridge, Philadelphia, Pa. (USGS site number 01467200), were collected almost continuously from April to November 2015. The procedures used to create figure 7 in this report were started with the 2011 report (DiFrenna and others, 2020) and are described here. The available long-term average daily temperature data were retrieved from the USGS NWIS database for April–November; the average value was computed for each month. Long-term average water temperatures were computed using data from 1964 to 2015 (fig. 7). In May, June, August, September, and November 2015, the monthly average temperatures were greater than the long-term mean monthly temperature (fig. 7). Monthly average temperatures were less than the respective long-term average in April, July, and October 2015 (fig. 7). The maximum daily mean water temperature of 27.3 degrees Celsius was recorded on July 31, and on August 1 and 2, 2015 (USGS, 2020d).
Specific Conductance and Chloride
Specific conductance is a measure of the capacity of water to conduct an electrical current and is a function of the types and quantities of dissolved substances in water (U.S. Environmental Protection Agency, 2016). As concentrations of dissolved ions increase, the specific conductance of the water also increases. Specific conductance measurements are good indicators of dissolved solids content and total ion concentrations, including chloride. Seawater and some artificial constituents can cause the specific conductance of estuary water to increase. Dilution associated with high freshwater inflows results in decreased levels of dissolved solids and lower specific conductance, whereas low inflows have the opposite effect.
The upstream movement of seawater and the accompanying increase in chloride concentrations are essential concerns for water supplies obtained from the Delaware River estuary (Kauffman and others, 2009). Water with chloride concentrations greater than 250 milligrams per liter (mg/L) is considered undesirable for domestic use, and water with concentrations exceeding 50 mg/L is unsatisfactory for chemically sensitive consumers and some industrial processes. Chloride concentrations in the estuary increase in a downstream direction with proximity to the Atlantic Ocean.
Specific conductance, not chloride concentration, was measured by the USGS at the streamgage at Reedy Island Jetty, Del. (USGS site number 01482800). Chloride concentrations at Chester, Pa. (USGS site number 01477050), were measured by Kimberly-Clark Chester Operations. The Delaware River Basin Commission provided those data, which are not derived from specific conductance data.
At the Reedy Island Jetty site, the greatest daily maximum specific conductance was 25,200 microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C) on February 18, 2015 (table 17, in back of report) (USGS, 2020h). The daily maximum specific conductance during the report year exceeded 3,780 µS/cm at 25 °C on approximately 99 percent of the 365 days with measured specific conductance values in the 2015 report year. The lowest daily minimum specific conductance was 721 µS/cm at 25 °C on April 24, 2015. The daily minimum specific conductance exceeded 3,780 µS/cm at 25 °C on 79 percent of the 365 days with measured specific conductance values in the 2015 report year.
The data measured by Kimberly-Clark Chester Operations at Chester, Pa., indicates the greatest daily maximum chloride concentration was 322 mg/L on October 28, 2015 (table 18, in back of report). During the report year, daily maximum concentrations exceeded 50 mg/L on about 79 percent of the 364 days on which measurements were taken. The lowest daily minimum chloride concentration was 36 mg/L on July 16 and 17, 2015. Daily minimum concentrations exceeded 50 mg/L on about 66 percent of the reported days, including from December 1 to 15, 2014, from mid-January to early April 2015, from mid-May to mid-June 2015, and from late August through the end of November 2015 (table 18).
Bar chart showing monthly average water temperatures in 2015 and long-term mean monthly water temperatures from 1964 to 2015, for April through November, in the Delaware River at Benjamin Franklin Bridge at Philadelphia, Pennsylvania (U.S. Geological Survey [USGS] site number 01467200; data from USGS, 2020d). Water temperatures are given in degrees Celsius.
Graphs showing the daily mean and minimum daily mean dissolved-oxygen concentrations, in milligrams per liter, averaged for July–September, annually, at two sites on the Delaware River estuary, 1965–2015, at (A) Delaware River at Benjamin Franklin Bridge at Philadelphia, Pennsylvania (Pa.) (U.S. Geological Survey [USGS] site number 01457200; data from USGS, 2020d); and (B) Delaware River at Chester, Pa. (USGS site number 01477050; data from USGS, 2020f).
Graphs showing percent distribution of quarter-hourly dissolved-oxygen concentrations, in milligrams per liter, at two sites on the Delaware River estuary, from July to September 2015 at (A) Delaware River at Benjamin Franklin Bridge at Philadelphia, Pennsylvania (Pa.) (U.S. Geological Survey [USGS] site number 01467200; data from USGS, 2020e); and (B) Delaware River at Chester, Pa. (USGS site number 01477050; data from USGS, 2020g).
Dissolved Oxygen
Dissolved oxygen in water is necessary for the respiratory processes of aquatic organisms and chemical reactions in aquatic environments (USGS, 2020a). The primary source of dissolved oxygen in the Delaware River estuary is diffusion from the atmosphere and, to a lesser extent, the photosynthetic activity of aquatic plants. The principal factors that affect dissolved-oxygen concentrations in the estuary are water temperature, biochemical oxygen demand, freshwater inflow, phytoplankton, turbidity, salinity, and tidal and wind-driven mixing.
Concentrations of dissolved oxygen at several sites on the Delaware River estuary have been measured since 1961 by the USGS. Two of these sites—the Delaware River at Benjamin Franklin Bridge at Philadelphia, Pa., and the Delaware River at Chester, Pa.—have nearly continuous records and are in the reach of the estuary most affected by effluent discharges, which can lead to reduced dissolved-oxygen concentrations because of increasing biological oxygen demand by aerobic bacteria in the water. For these sites, the daily mean and minimum daily mean dissolved-oxygen concentrations for the period of July–September during the 1965–2015 report years are shown in figure 8.
Although dissolved-oxygen concentrations increased considerably over this 51-year period, mean concentrations can vary from year to year. Due to technological changes and other factors, the process used to calculate mean dissolved-oxygen concentrations and the associated data values has changed over time. The procedures used to create figure 8 of this report were started for the 2009–10 Delaware River Master report (Russell and others, 2019). The available mean and minimum daily dissolved-oxygen concentration data were downloaded from the USGS NWIS database for July, August, and September, and the average mean and average minimum dissolved-oxygen concentrations of the daily values were computed over that 3-month period for each report year.
Dissolved-oxygen concentrations in the Delaware River estuary are usually highest near the Trenton site and decrease in a downstream direction. Concentrations commonly reach minimum levels in an area just downstream from the Benjamin Franklin Bridge site. During the report year, the lowest recorded daily mean concentration was 4.5 mg/L on September 13, 2015 (table 19, in back of report) (USGS, 2020d). Daily mean dissolved-oxygen concentrations were consistently 6.0 mg/L or greater from April 1 through June 1, 2015, and from October 1 through November 30, 2015. At the Chester site, the lowest recorded daily mean dissolved-oxygen concentration was 4.7 mg/L on July 22, 2015 (table 20, in back of report) (USGS, 2020f).
Histograms of quarter-hourly dissolved-oxygen concentrations during the critical summer period (from July 1 through September 30, 2015) at the Benjamin Franklin Bridge and Chester sites are presented in figure 9. During the 2015 critical summer period, quarter-hourly dissolved-oxygen concentrations were as low as 4.0 mg/L on 3 days (3.0 percent of measured days) at the Benjamin Franklin Bridge site and on 0 days (0 percent) at the Chester site (USGS, 2020e, g).
Hydrogen-Ion Activity (pH)
The pH of a solution is a measure of the effective concentration (activity) of dissolved hydrogen ions. Solutions with a pH less than 7 are acidic, whereas solutions with a pH greater than 7 are basic or alkaline. The pH of uncontaminated surface water typically ranges from 6.5 to 8.5. Major factors affecting the pH of surface water include the geologic composition of the drainage basin and human inputs, including effluent discharges. In addition, photosynthetic activity and dissolved gases, including carbon dioxide, hydrogen sulfide, and ammonia, can affect pH. The pH of water determines the solubility (the amount that can be dissolved in the water) and biological availability (the amount that can be used by aquatic life) of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (for example, lead, copper, and cadmium) (USGS, 2020b).
During the report year, pH was measured seasonally (April–November) at the Benjamin Franklin Bridge and Chester sites and continuously at the Reedy Island Jetty site. During these periods, the ranges of daily median pH measured at these sites are as follows: Benjamin Franklin Bridge, 6.7–7.6; Chester, 6.9–7.5; and Reedy Island Jetty, 7.2–7.8 (USGS, 2020d, f, h). The pH of water in the Delaware River estuary is usually lowest near the Trenton site and increases (water becomes more alkaline) in a downstream direction. The pH of water in the Delaware River estuary between the Benjamin Franklin Bridge site and the Reedy Island Jetty site was not a limiting factor for aquatic health or other beneficial water-uses during the report year.
Tables 1, 3–11, and 13–20
Table 1.
Precipitation in the Delaware River Basin upstream of Montague, New Jersey.[Data are from the National Weather Service, the New York City Department of Environmental Protection, and the Office of the Delaware River Master. in., inch; —, not applicable]
Table 3.
Storage in Pepacton Reservoir, New York, for report year ending November 30, 2015.[Delaware River Master daily operations record; gage reading at 0800 hours. Data provided by New York City, Department of Environmental Protection, Bureau of Water Supply. Storage is given in millions of gallons above the elevation of 1,152.00 feet. Add 7,711 million gallons for total contents above the sill of the outlet tunnel at the elevation of 1,126.50 feet. Storage at the spillway level is 140,190 million gallons. —, not applicable; Mgal/d, million gallons per day; ft3/s, cubic foot per second]
Change is calculated as the storage on the last day of each month minus the storage on the first day of each month. Net change for the year is +10,819.0 million gallons; minimum and maximum storage for December through May are 86,451 and 137,893 million gallons, respectively. Minimum and maximum storage for June through November are 96,810 and 140,394 million gallons, respectively.
Table 4.
Storage in Cannonsville Reservoir, New York, for report year ending November 30, 2015.[Delaware River Master daily operations record; gage reading at 0800 hours. Data provided by New York City, Department of Environmental Protection, Bureau of Water Supply. Storage is given in millions of gallons above the elevation of 1,040.00 feet. Add 2,584 million gallons for total contents above the sill of the outlet tunnel at the elevation of 1,020.50 feet. Storage at spillway level is 95,706 million gallons. —, not applicable; Mgal/d, million gallons per day; ft3/s, cubic foot per second]
Change is calculated as the storage on the last day of each month minus the storage on the first day of each month. Net change for the year is +18,351.0 million gallons; minimum and maximum storage for December–May are 44,255 and 96,253 million gallons, respectively. Minimum and maximum storage for June–November is 44,956 and 97,943, respectively.
Table 5.
Storage in Neversink Reservoir, New York, for report year ending November 30, 2015.[Delaware River Master daily operations record; gage reading at 0800 hours. Data provided by New York City, Department of Environmental Protection, Bureau of Water Supply. Storage is given in millions of gallons above the elevation of 1,319.00 feet. Add 525 million gallons for total contents above the sill of the outlet tunnel at the elevation of 1,314.00 feet. Storage at spillway level is 34,941 million gallons. —, not applicable; Mgal/d, million gallons per day; ft3/s, cubic foot per second]
Change is calculated as the storage on the last day of each month minus the storage on the first day of each month. Net change for the year is more than +9,612.0 million gallons; minimum and maximum storage for December–May are 21,919 and 34,513 million gallons, respectively. Minimum and maximum storage for June–November is 26,064 and 35,160 million gallons, respectively.
Table 6.
Diversions to New York City water supply system for report year ending November 30, 2015.[Delaware River Master daily operations record. Diversions in million gallons per day; data provided by New York City, Department of Environmental Protection, Bureau of Water Supply. —, not applicable. For December 1–May 31, the average is computed from June 1, 2013, to the given date. For June 1–November 30, the average is computed from June 1, 2014, to the given date. The diversion calculation is computed as authorized within the Decree]
Table 7.
Consumption of water by New York City from 1950 to 2015.[Data provided by New York City Department of Environmental Protection, Bureau of Water Supply. Mgal/d, million gallons per day]
Table 8.
Diversions by New Jersey, daily mean discharge, Delaware and Raritan Canal at Port Mercer, New Jersey (U.S. Geological Survey site number 01460440) for the report year ending November 30, 2015.[Data from U.S. Geological Survey, 2019e. All values except total are in million gallons per day (Mgal/d); total in million gallons (Mgal). e, estimated; —, not applicable]
Table 9.
New York City reservoir release design data from December 1, 2014, to October 31, 2015.[Delaware River Master daily operations record. The Montague design rate was 1,750 cubic feet per second (ft3/s). Column (col.) 1 data provided by electric utilities PPL Corporation and Talen Energy; col. 2 data provided by Eagle Creek Renewable Energy, LLC; col. 3 computed from index stations; col. 4 computed increase in runoff based on quantitative precipitation forecasts; col. 5 = col. 1 + col. 2 + col. 3 + col. 4; col. 6 = design rate − col. 5, when positive, otherwise col. 6 = 0; col. 7 = col. 14 (4 days earlier); col. 8, directed release amount from the Office of the Delaware River Master = col. 6 + col. 7, when positive, otherwise col. 8 =0; col. 9 = col. 7 from table 10; col. 10 = summation of col. 9; col. 11 = flow objective − (col. 9 + col. 10 from table 10) when positive, otherwise col. 11 = 0; col. 12 = summation of col. 11; col. 13 = col. 10 − col. 12; col. 14 = col. 13 divided by −10, limited to ±50 ft3/s; cols. 10, 12, 13, and 14 are accumulated from the previous water year starting June 1, 2014, with these values being reset on June 1, 2015; (ft3/s)-d, cubic foot per second accumulated daily]
Table 10.
Controlled releases from reservoirs in the upper Delaware River Basin and segregation of flow of Delaware River at Montague, New Jersey, for report year ending November 30, 2015.[Delaware River Master daily operations record. All provided measurements are the mean discharge in cubic foot per second for 24 hours.. Column (col.) 1 = directed release ordered by the Office of the Delaware River Master; col. 2 = 24 hours beginning 1200 of date shown; col. 3 = 24 hours ending 2400 one day later; col. 4 = 24 hours beginning 1500 one day later; col. 5 = 24 hours beginning 0800 of date shown; col. 6 = 24 hours beginning 1600 of date shown; col. 7 = col. 2 + col. 3 + col. 4 in response to direction (col. 1); col. 8 = col. 2 + col. 3 + col. 4 − col. 7; col. 9 = col. 5 + col. 6; col. 10 = col. 11 − col. 7 − col. 8 − col. 9; col. 11 = 24 hours of calendar day shown; col. 12 = Interim Excess Release Quantity (IERQ) Bank releases; —, not applicable]
Table 11.
Daily mean discharge, Delaware River at Montague, New Jersey (U.S. Geological Survey site number 01438500), for report year ending November 30, 2015.[Data from U.S. Geological Survey, 2019d. All values except the year’s total discharge volume are in cubic foot per second (ft3/s). The total volume discharged is given in cubic foot per second accumulated daily (ft3/s)-d. e, estimated; —, not applicable]
Table 13.
Daily mean discharge, East Branch Delaware River at Downsville, New York (U.S. Geological Survey site number 01417000), for report year ending November 30, 2015.[Data from U.S. Geological Survey, 2019a. All values except the year’s total discharge volume are in cubic foot per second (ft3/s). The total volume discharge is given in cubic foot per second accumulated daily ([ft3/s]-d). —, not applicable]
Table 14.
Daily mean discharge, West Branch Delaware River at Stilesville, New York (U.S. Geological Survey site number 01425000), for report year ending November 30, 2015.[Data from U.S. Geological Survey, 2019b. All values except the year’s total discharge volume are in cubic foot per second (ft3/s). The total volume discharge is given in cubic foot per second accumulated daily ([ft3/s]-d). —, not applicable]
Table 15.
Daily mean discharge, Neversink River at Neversink, New York (USGS site number 01436000) for report year ending November 30, 2012.[Data from U.S. Geological Survey, 2019c. All values except the year’s total discharge volume are in cubic foot per second (ft3/s). The total volume discharge is given in cubic foot per second accumulated daily ([ft3/s]-d). —, not applicable]
Table 16.
Daily mean discharge, Delaware River at Trenton, New Jersey (U.S. Geological Survey site number 01463500), for report year ending November 30, 2015.[Data from U.S. Geological Survey, 2019f. All values except the year’s total discharge volume are in cubic foot per second (ft3/s). The total volume discharge is given in cubic foot per second accumulated daily ([ft3/s]-d). e, estimated; —, not applicable]
Table 17.
Daily maximum and minimum specific conductance, Delaware River at Reedy Island Jetty, Delaware (U.S. Geological Survey site number 01482800), for report year ending November 30, 2015.[Data from U.S. Geological Survey, 2020h. Specific conductance measurements are in microsiemens per centimeter at 25 degrees Celsius. max, maximum; min, minimum; —, not applicable]
Table 18.
Daily maximum and minimum chloride concentrations, Delaware River at Chester, Pennsylvania (U.S. Geological Survey site number 01477050), for report year ending November 30, 2015.[Record provided by Kimberly-Clark Chester Operations. Concentrations are in milligrams per liter. max, maximum; min, minimum; *, missing data; —, not applicable]
Table 19.
Daily mean dissolved-oxygen concentrations, Delaware River at Benjamin Franklin Bridge at Philadelphia, Pennsylvania (U.S. Geological Survey site number 01467200), from April 1 to November 30, 2015.[Data from U.S. Geological Survey [USGS], 2020d. Concentrations are in milligrams per liter. As of January 20, 2020, USGS site number 01467200 is located at the Delaware River at Penn's Landing, Philadelphia, Pennsylvania. —, not applicable]
Table 20.
Daily mean dissolved-oxygen concentration, Delaware River at Chester, Pennsylvania (U.S. Geological Survey site number 01477050), from April 1 to November 30, 2015.[Data from U.S. Geological Survey, 2020f. Concentrations are in milligrams per liter. *, Missing data; —, not applicable]
References Cited
Delaware River Basin Commission [DRBC], 2022, Delaware Estuary Water Quality Monitoring Program: DRBC web page, accessed July 5, 2022, at https://www.nj.gov/drbc/programs/quality/boat-run.html.
DiFrenna, V.J., Andrews, W.J., Russell, K.L., Norris, J.M., and Mason, R.R., Jr., 2020, Report of the River Master of the Delaware River for the period December 1, 2010–November 30, 2011: U.S. Geological Survey Open-File Report 2020–1020, 127 p., accessed April 15, 2021, at https://doi.org/10.3133/ofr20201020.
Kauffman, G., Belden, A., and Homsey, A., 2009, Technical summary—State of the Delaware Basin report—A report on the health of the 13,539-square-mile Delaware River Basin in Delaware, New Jersey, New York, and Pennsylvania: West Trenton, N.J., and Wilmington, Del., Delaware River Basin Commission and Partnership for the Delaware Estuary, prepared by University of Delaware, 195 p., accessed March 11, 2019, at https://www.wrc.udel.edu/wp-content/uploads/2020/10/State-of-the-Delaware-Basin-Report-2008.pdf.
Russell, K.L., Ockerman, D., Krejmas, B.E., Paulachok, G.N., and Mason, R.R., Jr., 2019, Report of the River Master of the Delaware River for the period December 1, 2009–November 30, 2010: U.S. Geological Survey Open-File Report 2019–1093, 128 p. [Also available at https://doi.org/10.3133/ofr20191093.]
U.S. Environmental Protection Agency [EPA], 2016, Indicators—Conductivity: EPA web page, accessed August 7, 2018, at https://www.epa.gov/national-aquatic-resource-surveys/indicators-conductivity.
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Glossary
The following definitions apply to various terms and procedures used in the operations documented in this report.
- Balancing adjustment
An operating procedure used by the Office of the Delaware River Master to correct for inaccuracies inherent to the design of releases from the New York City reservoirs to meet the Montague flow objective at Montague, New Jersey. The balancing adjustment calls for more water to be released when previous directed releases (or a lack of releases) were insufficient to meet the Montague flow objective. This adjustment calls for less water to be released when previous directed releases were higher than required to meet the Montague flow objective. The balancing adjustment, based on provisional data, is computed as 10 percent of the difference between the cumulative adjusted directed release and the cumulative directed release required for exact forecasting. The balancing adjustment is applied to the following day’s release design. The maximum daily balancing adjustment is intentionally limited to preclude unacceptably large variations in the adjusted flow objective.
- Capacity
Total useable volume in a reservoir between the point of maximum depletion and the elevation of the lower crest of the spillway.
- Conservation releases
Controlled releases from the Pepacton, Cannonsville, and Neversink Reservoirs in New York designed to maintain specified minimum flows in stream channels immediately below the reservoirs (tailwaters). The following conservation release rate zones are defined in the June 1, 2015, Flexible Flow Management Program (appendix 1):
• L1—Spill mitigation when New York City combined reservoir storage is in the spill mitigation (L1) storage zone.
• L2—Conservation releases when New York City combined reservoir storage is in the normal (L2) storage zone.
• L3—Conservation releases when New York City combined reservoir storage is in the drought watch (L3) storage zone.
• L4—Conservation releases when New York City combined reservoir storage is in the drought warning (L4) storage zone.
• L5—Conservation releases when New York City combined reservoir storage is in the drought (L5) storage zone (also referred to as “Drought Emergency”).
- Directed releases
Controlled releases from New York City reservoirs in the upper Delaware River Basin, designed by the Office of the Delaware River Master to meet the Montague flow objective.
- Discharge mitigation release
These are releases designed to help mitigate the effects of spilling immediately below the Delaware River Basin reservoirs. The 2015 Flexible Flow Management Program details the releases in section 7 (appendix 1).
- Diversions
The out-of-basin transfer of water by New York City from the Pepacton, Cannonsville, and Neversink Reservoirs of New York State in the upper Delaware River Basin through the East Delaware, West Delaware, and Neversink Tunnels, respectively, to New York City’s water supply system. This includes the out-of-basin transfer of water by New Jersey from the Delaware River through the Delaware and Raritan Canals.
- Excess quantity
As defined by the Decree, the excess quantity of water is “equal to 83 per cent [sic] of the amount by which the estimated consumption during such year is less than the City’s estimate of the continuous safe yield during such year of all its sources obtainable without pumping.” The excess quantity shall not exceed 70 billion gallons, and the seasonal period for release of the excess quantity begins on June 15 and concludes on the following March 15.
- Flexible Flow Management Program (FFMP)
A set of rules for the management of storage, diversions, releases, and flow targets relating to the apportioning of water from the Delaware River Basin under the 1954 Decree of the Supreme Court of the United States and unanimously agreed to by the Decree Parties (Delaware, New Jersey, New York, New York City, and Pennsylvania). Refer to appendix 1.
- Index gaging stations
Specific sites on tributaries of the upper Delaware River where systematic observations of gage height and discharge are made. These stations are primarily used during the directed-releases season to help estimate inflows of surface water to the upper Delaware River.
- Interim Excess Release Quantity
An Interim Excess Release Quantity (IERQ) was defined in the Flexible Flow Management Program (appendix 1) and made available for interim periods from June 1, 2014, to May 31, 2015, and from June 1, 2015, to May 31, 2016. The IERQ is computed as 83 percent of the difference between the highest year’s consumption of the New York City water supply system during the period 2002–2006 (1,257 million gallons per day) and New York City’s current estimate of continuous safe yield of the New York City water supply system of 1,290 million gallons per day, obtainable without pumping. During the 2015 report year, the IERQ available for release was 15,468 cubic feet per second accumulated daily. 6,045 cubic feet per second accumulated daily of the IERQ is incorporated into the releases tables to enhance base releases from the New York City Delaware River Basin reservoirs.
- Interim Excess Release Quantity Extraordinary Needs Bank
From the 2015 Flexible Flow Management Program (appendix 1)—“In addition to the hydrologic criteria described in Section 2.5.6.A. [sic] of the Water Code and subject to other provisional uses of the IERQ as provided herein, the Decree Parties [Delaware, New Jersey, New York State, New York City, and Pennsylvania], the DRBC and the River Master may at any time review extraordinary water needs to support such research, aquatic-life, or other water-use activity as may be approved by the DRBC. Upon unanimous agreement, the Decree Parties may bank all or a portion of the IERQ remaining at such time, and such portion shall be placed in an IERQ Extraordinary Needs Bank and used to provide for such extraordinary water needs. Such quantity as may be so banked shall be deducted from the IERQ. Any unused Extraordinary Needs Bank water shall be returned to IERQ.”
- Key gaging stations
Specific sites on the East Branch Delaware River, West Branch Delaware River, Neversink River, Delaware and Raritan Canal, and mainstem Delaware River where continuous, systematic observations of gage height and discharge are made. These stations are used year-round in Office of the Delaware River Master operations.
- Maximum reservoir depletion
The minimum water-surface level or elevation below which a reservoir ceases to continue making delivery of quantities of water for all purposes for which the reservoir was designed. This is also referred to as the minimum full-operating level.
- Montague flow objective
In section 3a of the June 1, 2015, Flexible Flow Management Program (appendix 1), “Except with respect to limitations provided herein in Section 5, releases from the City Delaware Basin Reservoirs shall be in quantities designed to maintain, during Normal storage conditions, a minimum basic rate of flow at the gaging station of the U.S. Geological Survey at Montague, N. J. of 1,750 cubic feet per second (cfs), as directed by the River Master in accordance with Section VII. [sic] of the Decree. During Basinwide Drought Watch, Drought Warning, and Drought Emergency, in accordance with Section 5 of this Agreement and Section 2.5.3.B. [sic] and Tables 1 and 2 of the Delaware River Basin Water Code, the Montague flow objective shall vary based upon the time of year and location of the salt front, and minimum compensating releases shall be made by the City of New York from its reservoirs in the upper Delaware Basin.”
- Rate of flow
Mean discharge for a specified 24-hour period, measured in cubic feet per second (ft3/s) or million gallons per day (Mgal/d).
- Rate of flow at Montague
Daily mean discharge of the Delaware River at Montague, New Jersey, computed on a calendar-day basis.
- Reservoir-controlled releases
Controlled releases from reservoirs passed through outlet valves in the dams or turbines in powerplants. These releases do not include spillway overflow at the reservoirs.
- Salt front
The salt front is the 250 parts per million isochlor, or line of equal chloride concentration, in the Delaware River estuary. One part per million is one part of solute (in this case, chloride) per one million parts of solvent (river water). The 7-day average location of the salt front is used as an indicator of salinity intrusion in the Delaware River estuary and a factor affecting the Montague and Trenton flow objectives during drought emergencies.
- Storage or contents
Usable volume of water in a reservoir. Unless otherwise indicated, volume is computed based on the level of pool above the point of maximum depletion.
- Time of day
Time of day is expressed in 24-hour Eastern Standard Time, which, during the report year, included a 23-hour day on March 11 and a 25-hour day on November 4.
- Trenton flow objective
In section 3b of the June 1, 2015, Flexible Flow Management Program (appendix 1), “Section 2.5.3 of the Water Code establishes a set of equivalent flow objectives at Trenton, N.J. to control salinity intrusion in the Delaware Estuary. During Basinwide Drought Watch, Drought Warning, and Drought Emergency, in accordance with Section 5 of this Agreement and Section 2.5.3.B. [sic] and Tables 1 and 2 of the Water Code, the Trenton Equivalent Flow Objective shall vary based upon the time of year and location of the salt front, and minimum compensating releases shall be made by the City of New York from its reservoirs in the upper Delaware Basin.” The Delaware River Basin Water Code regulations are found in the Code of Federal Regulations (18 CFR part 410).
- Uncontrolled runoff at Montague
Runoff from the 3,480-square-mile drainage area above Montague, New Jersey, excluding the drainage area above the Pepacton, Cannonsville, and Neversink Reservoirs; Lake Wallenpaupack; and Rio Reservoir, but including spillway overflow at these dams.
Appendix 1. Agreement of the Parties to the 1954 Decree of the Supreme Court of the United States, Effective June 1, 2015
Full text of the Agreement consented to by the following Decree Parties: the State of Delaware, the State of New Jersey, the State of New York, the Commonwealth of Pennsylvania, and the City of New York.
Appendix 2. Temporary Modification to the Drought Entry Criteria Under the Flexible Flow Management Program
Full text of the agreement for a temporary modification to the 2014 Flexible Flow Management Program consented to by the following Decree Parties: the State of Delaware, the State of New Jersey, the State of New York, the Commonwealth of Pennsylvania, and the City of New York.
Conversion Factors
U.S. customary units to International System of Units
Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: °F = (1.8 × °C) + 32.
Datums
Vertical coordinate information is referenced to the Bureau of Water Supply datum, which was established by the New York City Department of Environmental Protection, Bureau of Water Supply.
Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).
Elevation, as used in this report, refers to distance above the vertical datum.
Supplemental Information
The term “cubic feet per second accumulated daily” is used as the descriptor for the volume measurement ([ft3/s]-d). Previous reports used the descriptor “cubic feet per second day” and “cubic feet per second for a day.” The units of measure are the same; the descriptor was changed to clarify that the measurement is one of volume rather than flow rate.
Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C).
Concentrations of chemical constituents in water are given in milligrams per liter (mg/L).
Abbreviations
Del.
Delaware
DRBC
Delaware River Basin Commission
FFMP
Flexible Flow Management Program
ft
foot
ft3/s
cubic foot per second
(ft3/s)-d
cubic foot per second accumulated daily
IERQ
Interim Excess Release Quantity
in.
inch
Mgal
million gallons
Mgal/d
million gallons per day
mg/L
milligram per liter
mi
mile
mi2
square mile
NAD 83
North American Datum of 1983
N.J.
New Jersey
N.Y.
New York
NYCDEP
New York City Department of Environmental Protection
NWIS
National Water Information System
ODRM
Office of the Delaware River Master
OST
Operational Support Tool
Pa.
Pennsylvania
USGS
U.S. Geological Survey
µS/cm at 25 °C
microsiemens per centimeter at 25 degrees Celsius
For more information about this report, contact:
Delaware River Master, Office of the Delaware River Master, U.S. Geological Survey.
Visit our website at:
https://webapps.usgs.gov/odrm/
Publishing support provided by the Reston Publishing Service Center
Disclaimers
Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.
Suggested Citation
Russell, K.L., Andrews, W.J., DiFrenna, V.J., Norris, J.M., and Mason, R.R., Jr., 2024, Report of the River Master of the Delaware River for the period December 1, 2014–November 30, 2015: U.S. Geological Survey Open-File Report 2024–1010, 96 p., https://doi.org/10.3133/ofr20241010.
ISSN: 2331-1258 (online)
ISSN: 0196-1497 (print)
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Report of the River Master of the Delaware River for the period December 1, 2014–November 30, 2015 |
| Series title | Open-File Report |
| Series number | 2024-1010 |
| ISBN | 978-1-4113-4550-8 |
| DOI | 10.3133/ofr20241010 |
| Publication Date | May 07, 2024 |
| Year Published | 2024 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Contributing office(s) | Office of the Associate Director for Water |
| Description | xi, 96 p. |
| Country | United States |
| State | Delaware, New Jersey New York, Pennsylvania |
| Other Geospatial | Delaware River |
| Online Only (Y/N) | N |
| Additional Online Files (Y/N) | N |