Reducing stormwater is an essential step toward increasing the health of the creek and the plants and animals who inhabit it.

The Stormwater Committee works on projects that slow down and clean stormwater runoff before it reaches our Creek. We educate the community about the effects of uncontrolled stormwater on Sligo Creek, how to capture it, and what people can do to reduce it in order to improve the creek’s health. We advocate for effective and sustainable stormwater management on the municipal, county, and state levels.

What is stormwater runoff?

Uncontrolled stormwater causes flooding, erosion, and carries pollution into Sligo Creek. Rain that falls on natural, grassy, or planted areas soaks into the ground. Rain that falls on hard surfaces like roads, roofs, and parking lots becomes stormwater runoff that carries litter, sediment, pet waste, motor oil, antifreeze and other chemicals and pollutants into the stream. Stormwater runoff causes flooding and erosion to the creek and surrounding areas.

Sligo Creek Parkway playground at Kennebec St

Above: Sligo Creek Parkway at Piney Branch July 2020 (video, at left) and the playground at Kennebec Street (at right)

What can we do about stormwater?

Slowing down and reducing stormwater can be done using various techniques and materials, depending on the size and nature of the problem, the location and the budget. Take a look at the Stormwater Resources page for some of the many steps you can take in your residential neighborhood, and at the Larger Stormwater Projects page for examples of projects around Sligo Creek that FOSC has been involved with. FOSC is currently active the Wheaton Branch Flood Mitigation project planned by DEP and DOT.

  • The Stormwater Resources page shows many steps you can take in your yard and neighborhood to increase permeability and reduce runoff.

Neighborhood Project: A Rain Garden on Hancock Avenue

A local neighborhood rain garden project featuring a great design, native plantings, and neighborhood cooperation. A simple and inspiring example for other neighborhoods seeking to manage stormwater and preserve the Creek.

Watershed Projects: Sligo Tree Boxes

People walk by the tree boxes in the Sligo Creek watershed all the time, oblivious to the tree boxes they are walking right by. A clever combination of concrete structures and natural processes, these boxes are a part of the County’s green streets program. What are they, how do they work, and why are they important?

Major Public Project: Wheaton Branch Flood Mitigation

Montgomery Parks, DOT and DEP are working to slow down stormwater along Sligo Creek through a collaborative project along the Wheaton Branch of Sligo Creek, the Wheaton Branch stormwater mitigation project.

The Wheaton Branch stormwater management pond, at the bottom right of the map below, collects stormwater from a highly developed 770-acre area of Wheaton.

Map of Wheaton Branch Flood Mitigation Project - issues

Highly developed land affects Wheaton stormwater runoff management

Wheaton Branch 100 year Existing Flood Plain courtesy of the Department of Environmental Protection, Montgomery County, MD
Wheaton Branch 100 year Proposed Flood Plain courtesy of the Department of Environmental Protection, Montgomery County, MD

Flood Plain Maps courtesy of DOT and DEP, Montgomery County, MD

During storms, water flowing into Wheaton Branch backs up as it reaches the undersized Dennis Avenue bridge, just north of the Wheaton Branch stormwater ponds. The result is significant flooding for residents in the area north of the bridge.

The existing 100 year floodplain map shows the flooding that affects residential properties and roadways for several blocks. Through an extensive re-engineering project, the proposed 100 year flood plain would be lowered and widened to direct floodwater away from homes along Glenhaven Drive and other nearby streets.

Ed Murtagh, longtime FOSC member and social media creator, created these videos 1) demonstrating how stormwater ponds function using the University Boulevard Stormwater ponds as an example, and 2) the components of the planned flood mitigation project at Wheaton Branch.

FOSC Suggestions made to DEP/DOT

During the public feedback period in January 2021, the FOSC Stormwater Committee sent a letter to DOT and DEP requesting clarification and suggesting project changes to enhance the flood mitigation project to further the County’s environmental goals.

  • Strategically place green infrastructure upstream of the current project and within the lowered flood plain to compliment existing engineered solutions.
  • Conduct an environmental impact statement (EIS) that considers the long term impact of the project as planned, and alternative designs for the project.

  • Expand the current project to include replacement of the lengthy concrete channel along Bucknell Drive with green infrastructure. This would slow runoff from this significant, sloped channel. 

  • Stabilize the stream banks along the upstream channels, with significantly greater riparian zones.

  • Address sediment/dredge material toxicity risks with testing for priority pollutants, and develop plans for disposal.
  • Provide water metrics and projections to residents near the earthen dams surrounding the stormwater ponds, including water volume pre-and-post project, water speed, and outflow from the riser in pond cell 3.

  • Quantify and share the projected change in outflow from the cell 3 and the risk of ecological and residential impact on the downstream area.

Lower Sligo in downpour, July 2020

Video courtesy of Kit Gage, Advocacy Committee Chair

The Dennis Ave Bridge during rain, Sept 2020

Video courtesy of Susan Morelli, FOSC Steward

Focus on: Wheaton Branch Flood Mitigation Project

Jan 27, 2021: DEP responded to the Stormwater Committee’s comments.

Jan 15, 2021 Update: FOSC Stormwater Committee submitted comments to DOT and DEP on Wheaton floodwater mitigations.

December 16, 2020 Update: DEP and DOT held a public informational meeting via Zoom for the Dennis Avenue Bridge Replacement and Wheaton Branch Flood Mitigation. The MoCo DEP major projects page has details.

December 2020 Update: FOSC Social media and Steward coordinator Ed Murtagh produced a video (see above and the FOSC Youtube channel) explaining the proposed Wheaton Branch Flood Mitigation Project.

October 2020 Update: FOSC submitted a letter to DEP requesting habitat improvements to the Wheaton Branch stormwater ponds.

September 2020 Update: FOSC Steward Susan Morelli recorded videos of high stormwater at the Dennis Ave. bridge.

You can read about other DEP projects on the Major Projects page, and about other Parks projects at Parks’ Stream Stormwater Management and Stream Restoration websites.

Other Stormwater Efforts

We are one of many groups in the Stormwater Partners Network working together for clean water in Montgomery County.

Join the Stormwater Committee

FOSC Stormwater Committee volunteers work around the Sligo watershed to help schools, neighborhoods and parks manage their stormwater more effectively. We teach communities and politicians about stormwater issues and promote more effective stormwater policies. The Committee meets about once a quarter via online conference.

To volunteer with the Stormwater committee, get in touch through the Contact form or, if you plan to join FOSC, through the Join FOSC form.