Improving the Physical & Biological Condition of Urban Stream in the City of Baltimore

In the early 1900s the stormwater or urban runoff is often conveyed by concrete infrastructure to prevent surface flooding or stormwater ponding in front of vertical or horizontal infrastructure in the Urban cities. It has caused many existing natural streams to be buried or replaced with stormwater pipe and concrete channel that has significantly impact the water quality, aquatic ecosystem, flooding, and existing nature in the urban cities. Currently, the existing stream in urban cities are deeply incised, channel bank vertical exposed and utilities (sanitary sewer lines, gas and water line), flows rarely extend to the floodplains, and no base flow to protect aquatic habitats. This unstable condition will continue to degrade without restoration. The City of Baltimore implemented urban stream restoration projects that has improved water quality, aquatic ecosystem and protect the existing utilities infrastructure to meet National Pollution Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permit under the federal Clean Water Act requirements. Using natural stream restoration approach by removing the concrete channel, daylighting stormwater pipe, reconnecting the floodplain, use of boulder types of structures to stabilizes the stream banks and reduce the energy of the stream system. This natural stream restoration design provided a stable stream system of supporting a biologically divers aquatic and riparian ecosystem, as well as provide a beautiful amenity to the communities. In addition, the stream restoration projects would provide the nitrogen, phosphorus, and sediment reduction into nearest watershed and meeting the Chesapeake Bay Total Maximum Daily Load goal.