Located at the base of Capitol Hill, the United State Botanic Garden (USBG) includes the Conservatory and surrounding landscapes, the National Garden, and Bartholdi Park. Its mission is demonstrating the aesthetic, cultural, economic, therapeutic, and ecological importance of plants to human beings. To reduce its pollutant contributions to the Potomac, to re-use stormwater, and to reduce its water bill, the USBG is reducing and eliminating stormwater flow to the sanitary sewer system and providing examples to the public of sustainable design strategies utilizing stormwater as a resource and promoting green infrastructure in urban settings. Since the Botanic Garden is visited each year by 750,000 people, it lends itself as an excellent demonstration, education, and outreach site.
As part of an Entech Engineering team, NTM Engineering aided the USBG and the U.S. Environmental Protection Agency Office of Wetlands, Oceans and Watersheds (OWOW) by proposing innovative vegetation uses in our built environment. NTM proposed a series of best management practices (BMPs) for collecting, storing, and re-using rainwater and suggested BMPs for green infrastructure, such as green roofs, water re-use, bioretention and rain gardens, and infiltration facilities.
Entech and NTM identified 16 “green” projects for the USBG. These projects will save water and sewage discharge to the combined sewer overflow (CSO) systems, along with an estimated water/sewer savings of 2.9 million gallons, and reducing 138 energy recovery units (ERUs) and 138,000 square feet of impervious surfaces. Again, these green solutions present opportunities to educate the public.
Highlights of Entech and NTM’s services include:
- Identifying USBG ground sites where stormwater capture, reuse, and infiltration opportunities exist
- Identifying BMPs applicable to the site, including bioretention areas, roadside bioretention areas, amended soils, cisterns, porous pavement (porous concrete, permeable interconnected concrete paver, porous concrete grids, plastic grid cells), infiltration trenches, green roofs, etc.
- Calculating the site’s water budget along with roof area capture zones
- Conducting a series of charrettes to educate all parties on the BMPs and their applications, to show the project’s progress, and to obtain input from interested parties.