Tetra Tech Wins DC Water Green Infrastructure Challenge
Tetra Tech team receives Green Infrastructure Challenge Award from DC Water and Washington, D.C., Mayor Vincent Gray. Pictured: George Hawkins (General Manager, DC Water), Vincent Gray (Mayor, Washington, D.C.), John Craig (Tetra Tech), Russ Dudley (Tetra Tech), Emily Leckvarcik (Toole Design Group), Andrew Gregson (Hazen & Sawyer), and Mike Clar (Tetra Tech).
DC Water selected Tetra Tech as one of seven winners of the first phase of its inaugural Green Infrastructure Challenge. The design competition promotes use of innovative and sustainable stormwater management practices such as green roofs, bioretention, rain barrels, and permeable pavement throughout Washington, D.C.
Tetra Tech partnered with Toole Design Group, a woman-owned business with expertise in bike infrastructure, and Hazen & Sawyer, an experienced stormwater management and green infrastructure engineering firm. The team now has an opportunity to compete to be one of the projects DC Water implements in neighborhoods throughout the District.
Tetra Tech’s winning design proposal for Lamont Park in the Mount Pleasant Business District introduces dedicated bicycle lanes with pervious pavement and conversion of an existing roadside tree box to a bioretention planter containing a tree and native grasses and shrubs. Tetra Tech worked with the District Department of Transportation (DDOT) to identify an appropriate area slated for future bike lane improvements, focusing on a growing business district.
Lamont Park is a small, triangular park bordered by three streets. The park is a community transportation hub, with both a Bikeshare kiosk and a bus stop and turnaround. It is home to many community events in this up-and-coming neighborhood, including markets, movie nights, and performances. While the park’s hardscaping is in good condition, the roadways are showing considerable wear.
The park is an ideal candidate for the proposed design, providing the opportunity for using green infrastructure for additional stormwater management to reduce runoff into the combined sewer. The project would also provide the community benefits of improving bike safety, promoting bike use, and improving the park as an amenity for neighboring businesses and residents. The team designed the Lamont Park project so that it could be replicated in other neighborhoods. The design allows for cost-effective, widespread implementation of green infrastructure to support the District’s goals for combined sewer overflow (CSO) reduction.
An innovative aspect of Tetra Tech’s design approach is the application of the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN), which we developed for the U.S. Environmental Protection Agency to evaluate the effect of low-impact development practices on stormwater management in the urban ecosystem. The team used dynamic stormwater modeling and long-term simulation of conditions to appropriately size and design green infrastructure features given local conditions. Dynamic modeling, combined with the use of simulated runoff during an average precipitation year, allowed the team to better evaluate how the features would respond to expected local conditions. The traditional approach sizes facilities using a design storm event.
The green infrastructure features will manage 70 percent of the park’s stormwater runoff volume before it reaches the combined sewer system. The team predicted that the project will meet or exceed the CSO target of 1.2 inches, consistent with DC Water’s Long Term Control Plan. Installation and maintenance costs for the green infrastructure are low, and return on investment is high. The team projects that over a 20-year project life cycle the cost will be just $0.022 per gallon of water managed.
“DC Water has made a significant commitment to sustainable stormwater solutions, and Tetra Tech was happy to contribute to their green infrastructure design challenge,” said Russ Dudley, Tetra Tech’s lead for this effort. “Winning an award was great recognition for our team’s efforts.”
Congratulations to our team, whose innovative design demonstrated how green and bike infrastructure can be integrated into urban ecosystems with minimal disruption, maximum benefit, and low cost.