Protecting shellfish at Wychmere Harbor, Harwich

Construction crews install a stormwater treatment system near Wychmere Harbor, Harwich.

by Lindsay Cook, Conservation Intern, Cape Cod Conservation District

The Cape Cod Water Resources Restoration Project recently completed another step in improving the water quality of our local shellfish beds. Before October 2011, there was a troubling situation at Wychmere Harbor in Harwich. Stormwater was flowing over 21,000 square feet of impermeable surface, picking up debris and environmental contaminants, before draining, untreated, into the harbor.

The town was concerned about this situation because Wychmere Harbor supports a valuable population of quahogs and is one of the few places Harwich residents can shellfish. To correct the situation, 55 flow diffusers, seven catch basins, and two leaching chambers were installed to catch and treat runoff coming from the Wychmere Harbor parking lot and the adjoining section of Harbor Road. 

“That's nice,” you might be saying to yourself... “But what does that all mean?”

First and foremost, it means that 14 acres of shellfish beds will benefit from the filtering of stormwater that previously ran untreated into the bay. During the treatment process, contaminants found in stormwater, such as fertilizers, metals, and fecal coliform bacteria are removed from the water, as well as the majority of its suspended solids.

This is good news for shellfishers because in order for shellfish beds to be harvested, the waters overlying the beds must meet rigorous water quality standards. To determine the water quality overlying the shellfish beds, researchers collect water samples and test for the presence of fecal coliform bacteria. In areas where there are high levels of fecal coliforms the shellfish beds are shut down.

Thanks to the stormwater treatment at Wychmere Harbor, local shellfishers should be able to harvest these valuable shellfish populations for years to come.