Delaware’s Center for the Inland Bays and the Department of Health and Social Services' Stockley Center are working to reduce stormwater runoff into Cow Bridge Branch.
Cow Bridge Branch is a stream that runs through Doe Bridge Nature Preserve, and drains into the Indian River. Nearby sits the DHSS’ Stockley Center campus, which has a hard surface that generates a lot of stormwater runoff. Delaware Center for the Inland Bays Director Chris Bason said when stormwater runoff moves, it picks up pollutants from the streets and carries them into the water.
“If the runoff is not treated, it can directly enter into streams where it can deposit that pollution,” Bason said. “The excess energy that it picks up can erode the streams and tear up the streams.”
Bason said his group and the Stockley Center are working to reduce stormwater runoff by slowing its flow and filtering it before it enters Cow Bridge. They’re putting plants near the water to absorb and naturally filter nitrogen and phosphorous from it, which could help restore natural habitat and water quality.
And finding ways to reduce that pollution would have a number of benefits, including an increase in the freshwater mussel population in Cow Bridge, Bason said.
“Pollution over time and also impediments to fish passage and migration into those streams have limited those populations,” Bason said. “But they still are there, and that’s actually an indicator of the quality of the stream there.”
The Center for the Inland Bays and the Stockley Center previously partnered in 2014 to restore a headwater channel of Cow Bridge. That project also slowed the flow of water and filtered runoff before it reached the stream.
They received a grant last July to address the runoff issue by turning a failed stormwater pond at Stockley into an area with native plants that can filter rainwater.