Article by Larry Jock
DE Reef Program sinks 2.6 million year old rocks
When the U.S. Army Corps of Engineers struck rock bottom during deepening of the Delaware River navigational channel, the state’s artificial reef program struck a new partnership with the Corps of Engineers for creating new fish habitat. Since last December, DNREC’s Fisheries Section and the Corps have partnered on a beneficial reuse project for converting nearly a million tons of rock removed from the river bottom into enhanced habitat for marine life on two artificial reef sites in the lower Delaware Bay – and at no cost to the state.
During the Corps of Engineers’ deepening of the river’s navigational channel to 45-feet to accommodate larger ships coming into port, two types of rock were encountered between Wilmington and Philadelphia: bedrock and more abundant glacial rock that washed downstream during the most recent ice age that spanned some 2.6 million years. In some parts of the river, almost 5 feet of bedrock (amounting to 355,000 tons) was removed to ensure the navigation depth. That rock was transported by and deployed to Delaware Reef Site #4, south of Bowers Beach and north of Mispillion Inlet, expanding the reef’s structure to 50 percent of its planned development by the Division of Fish & Wildlife.
Glacial rock taken from the river bottom yielded even more extraordinary reefing material for DNREC. From December through March, more than 635,000 tons of glacial rock was moved by barge to the Brown Shoal Reef Site #6 and piled in mounds 15 to 20 feet high amidst bottom consisting mostly of mud and sand. The addition of glacial rock means that Reef Site #6 is fully developed, expanding recreational fishing opportunities for the increasing number of anglers who fish Delaware’s world-class artificial reef system each year.
