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Basin Information
Illustration of the Delaware River Basin. 

The Delaware River:

Before we talk about the basin, let's talk about the river.

The Delaware is the longest un-dammed river in the United States east of the Mississippi, extending 330 miles from the confluence of its East and West branches at Hancock, N.Y. to the mouth of the Delaware Bay where it meets the Atlantic Ocean.

The river is fed by more than 2,000 tributaries, including 216 major ones, the largest being the Schuylkill and Lehigh rivers in Pennsylvania.

It is an interstate river its entire length; whenever you are standing on one of its banks, you are always looking across at another state.

From Trenton, N.J., 200 miles north to its headwaters in N.Y., the river is non-tidal and is characterized by clean, high quality waters. In fact, three-quarters of this section of the Delaware River is included in the National Wild and Scenic Rivers System.

From Trenton to the Delaware Bay, the river is tidal. This portion of the river is also known as the Delaware Estuary, where the river's freshwater mixes with the saltwater of the ocean.

In the Delaware Bay, the tidal change is about six feet, but in Trenton, it is about ten feet. 

While the entire tidal Delaware River is considered estuarine, salinity levels do change, from saltwater in the bay to mostly freshwater at Trenton, N.J. The river is considered brackish around Wilmington, Del.

The Delaware Estuary is part of the National Estuary Program, a project set up to protect estuarine systems of national significance.    

The Delaware has come a long way from its polluted past in the late 1800s to mid 1900s, and its clean-up is hailed as one of the world's top water quality success stories.

Today, the river supports a world-class trout fishery and year-round fish populations, as well as those returning to their natal waters to spawn, for example, the American shad, Striped bass, and the endangered Shortnose and Atlantic sturgeon

Bald eagles, which depend on fish as their primary food source, reside and nest throughout the basin from the river's New York headwaters to the Delaware Bay.

More horseshoe crabs breed on the shores of the Delaware Bay than anywhere else in the world.

Now that the river is cleaner, people are flocking back to its banks to live, work, and play.

River-based recreation, including boating and fishing, is one of the region's top economic sources. Pleasure craft marinas line waterfronts once visited only by commercial vessels. The river and many of its tributaries are flanked by attractive greenways, trails, and parks.

Officially designated water trails exist for the non-tidal and a portion of the tidal Delaware River, as well as Pennsylvania's Lehigh and Schuylkill rivers, the two largest tributaries to the Delaware.

The Delaware is also a working river, a huge economic engine for the region.

The Delaware River Port Complex (including docking facilities in Pennsylvania, New Jersey, and Delaware) is the largest freshwater port in the world. In 2018, the Maritime Exchange for the Delaware River and Bay issued a news release describing the results of a 2017 Delaware River Port Study that showed over 90 million tons of cargo moved through the regional ports, supporting over 190,000 jobs and over $85 billion in total economic activity.

Examples of products moved through the tri-state port complex include petroleum and petrochemical products, container cargo, forest products, and automobiles. It is the largest North American port for steel, paper, and meat imports as well as the largest importer of cocoa beans and fruit on the east coast. Over 65% of Chilean and other South American fruits imported into the United States arrive at terminal facilities in the tri-state port complex. Wilmington, Delaware is home to the largest U.S. banana importing port, handling over one million tons of this cargo annually from Central America.

Delaware River named the 2020 River of the Year by American Rivers

The Delaware River Basin:

The words watershed and basin are essentially synonymous, although, technically, a basin is a large watershed made up of smaller sub-watersheds. A watershed can be simply described as the area of land draining to a particular stream. When it rains, the rain will run-off the land into that local waterway, which then makes its way into larger bodies of water. The body of water and the surrounding land both make up the watershed. All of the watersheds that eventually drain to the Delaware River make up the Delaware River Basin.

There are 10 main sub-watersheds of the Delaware River Basin. The basin also includes portions of five physiographic regions: the Appalachian Plateau; Ridge and Valley; New England; Piedmont; and the Atlantic Coastal Plain.

The Delaware River Basin includes four states, 42 counties, and 868 municipalities. In all, it contains 13,539 square miles, including the 782 square-mile Delaware Bay. 

The basin drains only four-tenths of one percent of the total continental U.S. land area, including parts of:

 Pennsylvania (6,422 square miles or 50.3 percent of the basin's total land area);

 New Jersey (2,969 square miles, or 23.3%);

 New York (2,362 square miles, 18.5%); and

 Delaware (1,004 square miles, 7.9%)

DRB County and Municipality Information

Land cover varies from mostly tree canopy in the northern portion of the basin to more urbanized and farmland in the southern section. As expected, more impervious surface occurs in the more developed/urbanized sections of the basin. 

Just over 13 million people (about four percent of the nation's population) rely on the waters of the Delaware River Basin for drinking, agricultural, and industrial use, including those in Philadelphia and New York City. The 13.3 million figure includes about 5 million people in New York City and northern New Jersey who live outside the basin. New York City gets roughly half its water supply from three large reservoirs located on tributaries to the Delaware.

Nearly 6.6 billion gallons of water (pdf) are withdrawn from the basin each day; this includes ground and surface water withdrawals for a variety of uses, the main three being thermoelectric power generation, public water supply, and industry. While most water used within the basin is eventually returned to the basin, nearly one billion gallons a day is used consumptively, meaning it's withdrawn but not directly returned. The biggest consumptive users are out of basin diversions for NYC and northern N.J., which total almost 2/3 of all water in the basin that is used consumptively.

The Delaware River Basin supports a water-based economy of over $21 billion dollars annually, from recreation, water quality, water supply, hunting/fishing, ecotourism, forest, agriculture, open space and port benefits, and supports 600,000 jobs.

The non-tidal Delaware is not the only river stretch that includes sections Congressionally-protected by the National Wild and Scenic Rivers System. The White Clay Creek, draining parts of Pa. and Del., is included in the system, the only river in th country to be protected in its entirety. Sections of the Maurice River in New Jersey (a Delaware Bay tributary) and the Musconetcong River in New Jersey (a Delaware River tributary) are also part of the national system. According to the National Park Service's web site, the U.S. has 3.5 million miles of rivers, but only 12,734 river miles (~0.35%) are included in the National Wild and Scenic Rivers System.

Learn more Fun Facts about the Delaware River Basin

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