The Salt Water Barrier was a proposed project on the estuary of the
Delaware River
The Delaware River is a major river in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. From the meeting of its branches in Hancock (village), New York, Hancock, New York, the river flows for along the borders of N ...
, which was projected in the late 1950s to convert the lower reaches of the Delaware into a freshwater lake. The barrier was proposed as a high dam near
New Castle, Delaware, long, equipped with locks for the passage of shipping to Wilmington and Philadelphia. A study for the project was authorized by Congress in 1958, with engineering evaluations and public hearings by the
U.S. Army Corps of Engineers. The prime purpose of the project was to develop the lower river as a source of drinking water for communities along the lower river. Objections to the barrier included concerns about the oyster industry, shipping constraints, increased shoaling, ice formation, and most importantly, the possibility of trapping pollutants above the barrier. The project was found to be technically feasible, but not economically practical. It was not included in the final ''Delaware River Basin Report'' of 1962, which proposed reservoirs higher in the Delaware River basin, and no further action was taken.
Description
The location of the impoundment was set by the presence of the eastern terminus of the
Chesapeake and Delaware Canal
The Chesapeake & Delaware Canal (C&D Canal) is a -long, -wide and -deep ship canal that connects the Delaware River with the Chesapeake Bay in the states of Delaware and Maryland in the United States.
In the mid‑17th century, mapmaker Augus ...
south of New Castle, which was to remain a sea-level canal. Studies examined problems of ship passage, which would necessitate a system to flush the locks with pumped water to prevent salt water contamination. The study indicated that in the absence of regular tidal flushing there would be a buildup of pollutants in the impoundment that would render the fresh water reservoir unusable.
The barrier itself was proposed as a low dike built using hydraulic fill, armored against storms with concrete paving. An overflow spillway was to be set in a section of concrete structure, adjacent to four navigation locks that could accommodate vessels of more than draft.
A diameter tunnel was proposed to carry water from an intake structure near New Castle at a depth of about for in populated areas, or in a cut-and-cover trench in rural areas over to Hoopes Reservoir above Wilmington. Costs were projected in 1960 to be about $345,000,000 for the barrier, and between $35,000,000 and $45,000,000 for water tunnels. Costs for an alternative intake from the reservoir behind the existing
Conowingo Dam on the
Susquehanna River
The Susquehanna River (; Lenape: Siskëwahane) is a major river located in the Mid-Atlantic region of the United States, overlapping between the lower Northeast and the Upland South. At long, it is the longest river on the East Coast of the ...
were estimated to be between $140,000,000 and $170,000,000. Annual costs were estimated in the same proportion as the differences between the projects.
See also
*
Reber Plan
The Reber Plan was a late 1940s plan to fill in parts of the San Francisco Bay. It was designed and advocated by John Reber—an actor, theatrical producer, and schoolteacher.
San Francisco Bay Project
Under the plan, which was also known as the ...
, a similar proposal for San Francisco Bay
References
{{Coord, 39, 38, 53, N, 75, 33, 26, W, display=title
Delaware River
United States Army Corps of Engineers proposed dams