July 11, 2022

Completed Green Streets Project Captures Stormwater at the Source, Reduces Pollution and Erosion in Montgomery County, MD.

The Green Streets project reduces stormwater pollution flowing into Joseph’s Branch, a tributary to Rock Creek in Montgomery County, MD.

Community leaders recently joined dozens of residents to celebrate the completion of the Glenmont Forest and Wheaton Hills Green Streets Project in Montgomery County, MD.

The project reduces stormwater pollution flowing into Joseph’s Branch, a tributary to Rock Creek. RK&K identified environmental site design (ESD) and low-impact design restoration opportunities within the public right-of-way for the 237-acre study area within the watershed. Our Environmental Water Resources team evaluated water quality improvement options and alternatives and designed various types of best management practices (BMP) stormwater solutions, including rain gardens, bioretention facilities, and Filterra tree boxes, in order to help the county implement the ESD to the maximum extent practicable for the neighborhoods.

“The project was in an area of Montgomery County that was built in the 1950s without any stormwater quality or quantity management, and with minimal storm drain system infrastructure,” said Senior Project Engineer Kristianne Sandoval, PE. “The design includes facilities at 58 locations within the public right-of-way between the existing curb and sidewalk, or curb and private property line. A few facilities are located with-in curb extensions that provide traffic calming benefits in addition to the stormwater treatment benefit,” Kristianne added.

The project, which started in 2013, was completed by the Montgomery County Department of Environmental Protection to help meet the County’s MS4 permit and TMDL requirements. It captures stormwater at its source, reducing the amount and velocity of water hitting neighborhood streams, which reduces erosion and pollution.

The project faced several design constraints, but innovative solutions helped the team preserve natural resources and maximize the environmental benefit to the community.

“The retrofit facilities were implemented within the existing built environment to provide treatment of the stormwater runoff from adjacent roadways, driveways, and houses for downstream water quality improvement,” Kristianne said. “The best management practices facilities, which allow for onsite infiltration of runoff and groundwater recharge, use natural processes to filter out sediment and other pollutants. The plants in the facilities provide essential ecosystem benefits via nutrient uptake and habitat creation, as well as enhancement of neighborhood aesthetics.”

County leaders say the ongoing dialogue between RK&K, the county, and the community in the form of workshops and public meetings (both virtual and in-person) helped make the project a success.

“This project is unique in the sense that the project was requested by the community. Something we have not really seen before,” said Ryan Zerbe, Watershed Outreach Planner for Montgomery County. “ The community really understood the ‘why’ it was being done and were happy they were involved in “doing the right thing.”

Ryan noted how impressed residents are by the look and feel of the project.

“We have received many compliments about the look of the projects, often times from residents just driving down the street,” he said. “I think the residents will appreciate the beauty of the gardens and seeing the pollinators and colors as they walk throughout the neighborhood. Having a little less water on the streets is certainly a bonus too.”

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