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Delaware Deepening (Dormant, but expected to return when the Corps wants to go to 50 ft)

Editor’s note: This issue is currently dormant. We will continue monitoring the situation and may take up the issue in the future.


For over 20 years the Delaware Riverkeeper Network battled against the U.S. Army Corps of Engineers proposal to deepen the Delaware River’s main navigation channel from 40 to 45 feet.   After grassroots organizing, advocacy and litigation the Army Corps finally got all of the approvals and funding it needed to start the project in 2010.  In 2019 the deepening work is still ongoing, with blasting taking place in the River in areas critical for our federal endangered sturgeon.

The deepening will have long term and enduring environmental and economic impacts on our River and region.

Economically Deepening is a Big Loser…

Three times the Government Accountability Office  questioned and/or challenged the claims of economic benefit made by the Army Corps of Engineers for its proposed Delaware River Deepening Project.  In May 2011 the Army Corps, without any public awareness or announcement, completed its 8th economic review of the project in which it once again concluded the project was cost beneficial.  Having secured a copy of this report as the result of a Freedom of Information Act the Delaware Riverkeeper Network secured an independent review which found basic and fundamental flaws in the analysis done by the Army Corps and which proves their positive economic claims for the project are over-inflated and misrepresent reality. In short, merely correcting for a fundamental and basic economic analysis flaw identified the benefit-cost ratio for the project falls to a mere 1.1 to 1, i.e. at best one can claim 10 cents of net taxpayer benefit for every $1 invested in the Delaware River deepening project.  When additional errors are taken into consideration, this figure falls even further, supporting a conclusion that when accurately assessed the Delaware Deepening project yields less than $1 of benefit for taxpayers for every $1 they invest – i.e. it is a net loss for the taxpayers and therefore cannot warrant the nearly $300 million it requires for construction.  The new analysis also showed that the ports will continue to get traffic without a deepened channel and that the Army Corps knows this.

Environmentally Deepening is a Big Loser…

When it comes to the environmental and community harms, for years, agencies and environmental experts relying on sound scientific principles have documented the depth and breadth of the threats that deepening the River poses.  Those questioning the project include: the U.S. Fish and Wildlife Service, the National Marine Fisheries Service, the Delaware River Basin Commission, the Delaware Department of Natural Resources and Environmental Control, the New Jersey Department of Environmental Protection, the University of Delaware’s Sea Grant Program, and more.

Environmentally, deepening the channel changes the movement and balance of fresh and salt water in a way that will move the salt line up river, threatening drinking water supplies and economically important oyster populations.  A multitude of species rely on the Delaware River for spawning; a changing salt line could diminish available freshwater spawning grounds that put at risk species like the Atlantic and shortnose sturgeon already in jeopardy of extinction. A changing salt line also risks the transformation of freshwater marshes, damaging the food and habitat they provide to a variety of fish and wildlife species important both ecologically and economically to the region.

A moving salt line is also a major threat to the oyster populations of the Delaware Estuary. The shifting salt line threatens significant changes, including the reintroduction of parasites and disease to the River’s oysters that in the past decimated these populations.  Oysters are vital to the ecology of the Delaware.  Oysters act as a vital food source for many of the River’s creatures and are important filters for pollution found in Estuary waters. Delaware Estuary oysters represent an important source of commercial value to the Delaware Estuary and Bay region. The annual harvest of oysters from the Delaware Estuary generates up to $80 million of annual economic benefit for the region, much of this in some of the region’s poorest communities that could not tolerate the loss of jobs, revenue and benefit if oyster populations decline.

Home to the largest spawning population of horseshoe crabs in the world

The Delaware Bay is home to the largest spawning population of horseshoe crabs in the world.  Every season, migratory shorebirds descend on Delaware Bay to feast on the eggs of the horseshoe crabs. The deepening project directly threatens the horseshoe crabs and their ability to successfully spawn in key areas in Delaware and, as a result, poses unacceptable threats to migratory birds already in decline because of a lack of needed horseshoe crab eggs. Horseshoe crabs and the migratory birds dependent on them bring a $34 million boost to the region’s ecotourism industry every year. Nationally, horseshoe crabs represent a substantial benefit to the biomedical industry, to which one pint of Horseshoe Crab blood is worth $15,000 for required testing on medical devices, vaccines and intravenous drugs, representing $150 million of annual revenue and social welfare value.

According to experts, the deepening project and associated spoil disposal will introduce heavy metals, pesticides, and other toxins into the River, reintroducing them into the environment and food chain, and putting at risk drinking water aquifers important to communities in New Jersey and Delaware.

Deepening would change water patterns in such a way that it will exacerbate erosion of wetlands. Wetlands are important ecologically, aesthetically and provide important protection during catastrophic storm events. The list of harms goes on.

Already we are hearing noises about deepening the River to 50 feet — so this is a battle that may be dormant for now but is likely to return.


Litigation: Delaware Riverkeeper, et. al. v. US Army Corps of Engineers



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