Envirotech proposes dredging at Lake Gerar

The firm managing Lake Gerar in Rehoboth Beach says the lake should be dredged.

The proposal by Envirotech President Todd Fritchman came after Envirotech spent close to a year analyzing the buildup of sediment in part of the lake near Olive and Lake avenues. Fritchman’s analysis was presented to the city commissioners Nov. 6.

Envirotech’s $50,000 plan has two phases. First, remove peat and associated vegetation. Fritchman said removing peat facilitates dredging, as it reduces the risk that dredges will become clogged.

The second phase calls for dredging a 6,100-square-foot area part of the lake, with the spoils placed in a dewatering bag nearby, Fritchman said. All told, Envirotech’s plan calls for removing 800 cubic yards of sediment. By comparison, when Henlopen Acres dredged its marina in 2013, the project removed 4,000 cubic yards of material at a cost of $198,000.

Fritchman said he could not estimate the costs of removing the dewatered spoils because it depends on where they are taken. Using a dewatering bag, he said, reduces the volume of the spoils by 50 percent or more. Fritchman said the job can be done in three to four weeks and should take place during the late fall or winter months to avoid beach traffic.

Envirotech restored Lake Gerar in 2005, installing sediment controls, aerators and vegetative buffers. The firm has maintained the lake ever since, but Fritchman told the commissioners in February that runoff and yard waste were reducing water depth near the Garden of the Navigators. Fritchman said Lake Gerar is one of only a few naturally occurring lakes in the state.

Fritchman said problems include vegetation spreading into the lake, stormwater runoff, and composted material being dumped into the lake by nearby property owners. These discharges into the lake turn into organic material and form peat bogs, he said.

“An island is forming, in essence,” he said.

The buildup of peat and muck in the lake chokes off the oxygen supply to fish, Fritchman said.

He said as far as he knows, Lake Gerar has not been dredged in 50 years.

To fund the dredging, Fritchman suggested a community water quality grant from the state Water Infrastructure Advisory Council. He said Dewey Beach got a similar grant for retrofitting stormwater pipes to ease flooding.

Fritchman said the Rehoboth commissioners would have to lead the way in seeking the grant. The commissioners did not commit to any specific action.