The
Delaware River is a major river on the
Atlantic coast of the
United States.
The Delaware was explored by
Adriaen Block as part of the
New Netherlands Colony, and was named the
South River to mark the southernmost reach of that colony.
The river meets tide-water at
Trenton, New Jersey. Its total length, from the head of the longest branch to
Cape May and
Cape Henlopen, is 410 miles (660 km), and above the head of the
Delaware Bay its length is 360 miles (579 km). The mean freshwater discharge of the Delaware River into the estuary is 11,550 cubic feet (330 m³) per second.
The Delaware River constitutes, in part, the boundary between
Pennsylvania and
New York, the entire boundary between
New Jersey and Pennsylvania, and most of the boundary between
Delaware and New Jersey. A historical oddity, the Delaware-New Jersey Border is actually at the eastern-most river shoreline within the
Twelve-Mile Circle of New Castle, rather than the usual mid river or mid channel borders, causing small portions of the New Jersey peninsula falling west of the shoreline to fall under the jurisdiction of Delaware. The rest of the borders follow a mid-channel approach.
Commerce was once important on the upper river, primarily prior to railway competition (1857).
The mean tides below
Philadelphia are about . The magnitude of the commerce of Philadelphia has made the improvements of the river below that port of great importance. Small improvements were attempted by
Pennsylvania as early as 1771.
In the "project of 1885" the United States government undertook systematically the formation of a 26 ft (8 m) channel 600 ft (180 m) wide from Philadelphia to deep water in
Delaware Bay. The River and Harbor Act of 1899 provided for a 30 foot (9 m) channel 600 feet (180 m) wide from Philadelphia to the deep water of the bay.
Course
The main,
west or Mohawk branch rises in
Schoharie County, New York, about 1886 feet (575 m) above the sea, near
Mount Jefferson, and flows tortuously through the plateau in a deep trough, impounded at one point to create the
Cannonsville Reservoir, and then becoming the state boundary at the
42nd parallel, until it emerges from the
Catskills. Similarly, the
East Branch begins from a small pond south of
Grand Gorge in the
town of
Roxbury in
Delaware County, flowing southward toward its impoundment by New York City to create the
Pepacton Reservoir, the largest reservoir in the
New York City water supply system. The
confluence is just south of
Hancock.
After leaving the mountains and plateau, the river flows down broad
Appalachian valleys, passing
Hawk's Nest overlook on the "Upper Delaware Scenic Byway". Below
Port Jervis, New York, the Wallpack Ridge deflects the Delaware into the Minisink Valley, where it follows the southwest
strike of the eroded
Marcellus Formation beds along the Pennsylvania–New Jersey state line for to the end of the ridge at Wallpack Bend in the
Delaware Water Gap National Recreation Area.
The Minisink is a
buried valley where the Delaware flows in a bed of
glacial till that buried the eroded bedrock during the
last glacial period. It then skirts the
Kittatinny ridge, which it crosses at the
Delaware Water Gap, between nearly vertical walls of
limestone, and passes through a quiet and charming country of farm and forest, diversified with plateaus and escarpments, until it crosses the Appalachian plain and enters the hills again at
Easton, Pennsylvania. From this point it is flanked at intervals by fine hills, and in places by cliffs, of which the finest are the Nockamixon Rocks, 3 miles (5 km) long and above 200 feet (60 m) high.
At Trenton there is a fall of 8 feet (2.4 m). Below Trenton the river flows between
Philadelphia and
New Jersey before becoming a broad, sluggish inlet of the sea, with many marshes along its side, widening steadily into its great estuary, Delaware Bay.
Tributaries
Its main
tributaries in New York are the
Mongaup and
Neversink rivers and
Callicoon Creek; from Pennsylvania, the
Lackawaxen,
Lehigh, and
Schuylkill rivers; and from New Jersey,
Rancocas Creek and the
Musconetcong and
Maurice rivers.
Oldmans and
Raccoon creeks are tributaries in New Jersey.
A 1655 Swedish nautical chart showing part of the Delaware River. The map is from when Delaware River was under the Swedish colony
New Sweden.
.
Flooding
The Delaware has experienced a number of serious flooding events as the result of snow melt and/or rain run-off from heavy rainstorms. Record flooding occurred in August 1955, in the aftermath of the passing of the remnants of two separate hurricanes over the area within less than a week: first
Hurricane Connie and then
Hurricane Diane, which was, and still is, the wettest tropical cyclone to have hit the northeastern United States. The river gauge at Riegelsville, PA recorded an all time record crest of 38.85 feet on August 19, 1955.
More recently, moderate to severe flooding has occurred along the river. The same gauge at Riegelsville recorded a peak of 30.95 feet on September 23, 2004, 34.07 feet on April 4, 2005, and 33.62 feet on June 28, 2006, all considerably higher than the flood stage of .
Since the upper Delaware basin has few population centers along its banks, flooding in this area mainly affects natural unpopulated flood plains. Residents in the middle part of the Delaware basin experience flooding, including three major floods in the three years (2004-2006) that have severely damaged their homes and land. The lower part of the Delaware basin from Philadelphia southward to the Delaware Bay is tidal and much wider than portions further north, and is not prone to river related flooding (although tidal surges can cause minor flooding in this area).
The
Delaware River Basin Commission, along with local governments, is working to try to address the issue of flooding along the river. As the past few years have seen a rise in catastrophic floods, most residents of the river basin feel that something must be done. However, due to insufficient federal funds, progress is slow.
New York City Water Supply
After
New York City had made 15 reservoirs (with more to come) for their water supply, and with a growing population, the city tried to gain permission to make five reservoirs along the Delaware River's tributaries. However, they were denied the permission to impound the Delaware's tributaries to make new reservoirs. So in 1928, New York City decided to draw water from the Delaware River to feed the population boom that had started during the beginning of the
Great Depression. There were, however, villages and towns across the river in
Pennsylvania that were already using the Delaware for their water supply. The two sides eventually took their case to the
U.S. Supreme Court, and in 1931, New York City was finally allowed to draw 440 million gallons of water a day from the Delaware and its upstream tributaries.
Crossings
The Delaware River is a major barrier to travel between
New Jersey and
Pennsylvania. Most of the larger bridges are tolled only westbound, and are owned by the
Delaware River and Bay Authority,
Delaware River Port Authority,
Burlington County Bridge Commission or
Delaware River Joint Toll Bridge Commission.
Washington's crossing of the Delaware
Perhaps the most famous “Delaware Crossing” involved the improvised boat crossing undertaken by
George Washington’s army during the
American Revolution on
Christmas Day, 1776. This led to a successful surprise attack on the
Hessian troops occupying
Trenton, New Jersey.
Major oil spills
A number of
oil spills have taken place in the Delaware over the years.
- 01-31-1975 — 11,000,000 gallons of crude oil spilled from the Corinthos tanker
- 09-28-1985 — 435,000 gallons of crude oil spilled from the Grand Eagle tanker after running aground on Marcus Hook Bar
- 06-24-1989 — 306,000 gallons of crude oil spilled from the Presidente Rivera tanker after running aground on Claymont Shoal
- 11-26-2004 — 265,000 gallons of crude oil spilled from the Athos 1 tanker; the tanker's hull had been punctured by a submerged, discarded anchor
See also
