Purpose: Restore a 1,600 foot stream that had been eroded from increased stormwater runoff after the construction of the weigh station on Highway 301, resulting in 30 ft deep cuts in what once was a natural stream.
Project: A series of rock stepped pools, followed by regenerative bioretention beds slow and infiltrate storm flow, thereby reducing the erosive energy as it moves downstream. This creates a cleaner and more docile stream entering the Sassafras. Additionally, eroded outer meander bends of the stream that had become sharp hairpin turns due to the increased flow of strormwater were relocated and stabilized. Cross veins and veins were constructed along the stream to redirect flow to the natural channel in areas where the stream had been cutting into the surrounding banks and to maximize riffle, run and pool habitat and biodiversity.
Bioretention measures will also be installed upstream of the restoration in order to filter and infiltrate excessive stormwater originating from the highway and weigh station. Runoff source control measures including concrete swale removal, bioswales with stepping check dams, rock step pools, and regenerative bioretention conveyances are proposed along Route 301 in the median and right of way, and at the tributary headwater areas.
Cost: $880,000 funded by Maryland DNR, Maryland State Highway Administration, and the Natural Resource Conservation Service
Pollution Reductions: 35 lbs of nitrogen, 465 lbs of phosphorus, and 105 tons of sediment annually.