By Sara Sayed, DRBC Water Resource Scientist
The Delaware River Basin is a powerhouse of culture, economy and history. Our Basin is also notable for its large size-to-service ratio, meaning the Delaware River Basin drains only 0.4% of land in the contiguous United States, but approximately four percent of the U.S. population relies on its waters for drinking, agricultural and industrial use.
Managing the Delaware River Basin’s interstate resources is no small feat. In 1961, the formation of the Delaware River Basin Commission (DRBC) brought together four states – Delaware, New York, New Jersey, and Pennsylvania – and the federal government to manage our shared waters without regard to political boundaries. Since then, the DRBC has made strides in managing water shortages, water quality and other water resources challenges.
Population Served by the Delaware River Basin. Credit: DRBC.
The Commission is responsible for ensuring adequate water supply for the Basin, including long-term water supply planning. To project long-term water needs, we need to understand how and where water is currently being used. Armed with more recent census data and fresh information about out-of-basin water use, DRBC has just updated the population served—now estimated at 14.2 million.
Who lives in the basin?
The DRBC’s last Population Served estimate was from July 2018 based on census year 2016 information. At that time, the total population served by the Basin’s water was estimated at 13.3 million, while the actual population in the Basin was estimated at 8.34 million.
The estimated population in the Basin has increased to 8.63 million, an increase of 0.29 million over the last census data. Pennsylvania and New Jersey saw the largest increases, with 187,000 and 52,000 more residents, respectively. There was also a small decline in New York state’s in-basin population.
Who else uses Delaware River Basin water?
DRBC staff working on the Delaware River. Credit: DRBC.
Nearly 6.4 billion gallons of water are withdrawn from the Basin each day, supporting the water needs of two of the nation's largest cities - Philadelphia and New York City - as well as approximately one million people in northern New Jersey. The latter are in the form of out-of-basin diversions to New York and New Jersey, which means water is withdrawn in the Basin but not returned to it.
Though not in the Delaware Basin, roughly half of New York City’s water supply as well as supply to communities along the transmission route, is provided from the Basin’s Cannonsville, Pepacton and Neversink Reservoirs by New York City Department of Environmental Protection.
In central New Jersey, water from the Delaware River is diverted through the Delaware & Raritan Canal to serve communities along its route, a transmission process owned by the State of New Jersey and operated by the New Jersey Water Supply Authority.
And finally, the Chester Water Authority in Chester County, Pennsylvania, is an example of a straddled system, serving an area partially within and partially outside of the Delaware River Basin.
For the latest update, DRBC worked with our partners at New York City Department of Environmental Protection, New Jersey Department of Environmental Protection, and the Chester Water Authority to obtain up-to-date water use figures.
DRBC process to update Population Served. Credit: DRBC.
Why does this number matter?
A complete Population Served figure enables the DRBC to track water demand. The data provide DRBC with critical information on real-life needs of individuals, communities, and industries to balance with flow, ecosystem and other considerations. In assessing these trends, the DRBC ensures that the data inform the Commission’s water management and future water availability.
Population Served can also be a useful tool for partners who educate, inform and support our work. This may mean supporting narratives about water availability and resiliency, to connecting with policymakers whose districts benefit from Basin water, and even educating communities on how they are connected to the resources of the Basin.
With a current picture of who is connected to the Basin, the DRBC has a strong roadmap to guide water resource management. Data tells stories, and stories are powerful connectors, bringing the size-to-service concept to life. The story of the Delaware Basin is a story of shared resources for the benefit of over 14 million people.
For more information on this project, visit: https://www.nj.gov/drbc/library/documents/sayed_DRB_PopulationServed_CDRWwebinar061423.pdf.