DGS04-8 Summary of Flows in the Delaware River at Trenton and Montague with Major Upstream Diversions, 1913-2002

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Abstract

This product is an Excel workbook (called ‘DelQ.xls’) which documents annual, seasonal, and monthly flows in the Delaware River at the Trenton and Montague streamflow gages, along with annual and monthly withdrawals by major upstream intakes. Only surface-water intakes that export water from the Delaware River watershed upstream of the Trenton gage are included. This is defined as ‘depletive’ water use. Surface-water and ground-water withdrawals for use in the basin upstream of Trenton are not included. Changes in storage in reservoirs may also affect streamflows but these changes are not documented here.

There are four major depletive users upstream of the Trenton gage. They are, in order from upstream to downstream:

1) New York City has been diverting water from the Delaware watershed to the Hudson watershed since 1954. Diversions are made from the Cannonsville Reservoir on the        West Branch Delaware River, the Pepacton Reservoir on the East Branch Delaware River, and the Neversink Reservoir on the Neversink River.

2) The Delaware and Raritan Canal withdraws water from the Delaware River near Raven Rock in Hunterdon County, New Jersey. The canal was completed in 1834. It has      been utilized as a water supply since 1948. Water is diverted primarily to the Raritan watershed.

3) The Point Pleasant pump station removes water from the Delaware River near Point Pleasant in Bucks County, Pennsylvania. It has supplied water to the Philadelphia      Electric Company, the North Wales Water Authority, and the North Penn Water Authority since 1989. The water is returned to the Delaware River via the Schuylkill River,            after some consumptive loss, below the streamflow gage at Trenton.

4) Trenton City has withdrawn water from the Delaware River in Mercer County, New Jersey, since at least 1925. The water is withdrawn upstream of the Trenton streamflow gage and returned to the Delaware River, after some consumptive loss, below the gage.

In 2002 New York City exported 182 billion gallons of water out of the Delaware basin and the Delaware and Raritan Canal 29 billion gallons. Withdrawals in 2002 by the Point Pleasant pump station (13 billion gallons) and Trenton City (7.6 billion gallons) were returned to the Delaware River, after some consumptive loss, below the Trenton streamflow gage.

‘Consumptive’ water use is defined as evaporative use in the watershed. Water that is withdrawn, used, and then returned to the same watershed is subject to some consumptive loss. The percentage consumptive loss depends on the specific use the water is put to and the season. In the New Jersey portion of the watershed above the Trenton gage the consumptive water loss is estimated to have been 4.4 billion gallons in 1999 based on unpublished data on file with the N.J. Geological Survey. Based on relative estimates of population, consumptive water use in the Pennsylvania and New York portions of the watershed above the Trenton gage may have been about twice as much. Total consumptive water loss in the Delaware watershed upstream of Trenton is thus roughly estimated to have been on the order of 15 billion gallons in 1999.

This workbook (DelQ.xls) includes a number of data tables, analysis tables, and graphs. The purpose of this workbook is to provide these data in a consistent and usable format to interested parties.