A window into the restoration of a stream and pond system: the Bedfordshire Project
Did you know that the Department of Environmental Protection restores streams and creeks throughout Montgomery County? The Restoration Team at DEP has been working on a project to restore a stream and retrofit a stormwater pond in the Bedfordshire neighborhood, to help reverse the effects of decades of largely uncontrolled runoff in the Kilgour Branch Stream Valley Park.
Located in Potomac on a tributary to Watts Branch, over 1,000 feet of stream were restored in this project and a stormwater management pond at the end of the stream was completely rebuilt.
Why did we choose Kilgour Branch for this project?
As is the case in many streams in Montgomery County, the Bedfordshire stream was actively eroding prior to this project, leading to three- to four-foot vertical eroded banks, sedimentation, and poor habitat for aquatic life. The stormwater management pond lacked modern design features for improving water quality, controlling small and large storm flows, and ensuring dam safety.
The changes we made:
The restored stream now features a series of pools and cobble weirs that carry small flows, while allowing large flows to spread out on the floodplain within the park. By reconnecting the stream to its floodplain, we are working to protect downstream waters by reducing the energy and velocity of the flow. More nutrients and sediment are retained in the floodplain, recreating natural processes, instead of sending them downstream.
The eroded channel is now stable, with enhanced habitat for fish and amphibians. It also improves stream health by replenishing groundwater and increasing “baseflow,” which is the normal stream flow in between storms. Native trees and other vegetation have been planted to add habitat and ecological diversity.
The restored stream flows into the stormwater pond, which provides water quality treatment in a newly-created “wet pool.” The wet pool is a permanent area of ponded water, several feet deep, that retains water in between storms. The rebuilt pond also has re-graded slopes and a safety bench to increase public safety, a fully rebuilt dam embankment, and a new riser (flow control structure) and outflow pipe. In addition to removing pollutants from runoff, the pond now controls the outflow rate from small, frequently-occurring storms for the first time, helping to protect Kilgour Branch from further erosion.
Now substantially complete after construction in 2016 and 2017, the stream and pond treat runoff from 265 acres (0.4 square miles). The drainage area includes neighborhoods south of Glen Road, west of Falls Road, and northwest of the Falls Road Golf Course, and includes 70 acres of impervious surfaces such as roads, driveways, roofs, and parking lots. By restoring natural functions and improving stormwater management, the Bedfordshire project helps to ensure clean, healthy streams in the local community and downstream to the Potomac River and Chesapeake Bay.
To learn more about this restoration project, please visit the Bedfordshire Stormwater Pond and Stream Restoration page on the DEP website. To learn more about other projects throughout the County, take a look at the Watershed Restoration page on DEP’s website, and to learn more about projects you can do on your own property, please visit the RainScapes page.
We invite you to scroll through the photos below to see more images of the construction process and restoration progress!