Something that has always annoyed me as I drive through deserts and other arid lands is the canals and reservoirs in which water is evaporating as transported and held for use. Why not cover them to prevent evaporation and contamination? The District of Columbia is not dry, but DC Water covers its reservoirs and has covered its Fort Reno reservoir with a nearly-one-acre green roof.
The roof serves not only an environmental purpose but also an educational one. A summer program, called Growing Futures, teaches students the skills necessary for becoming employed in the green economy.
The green roof is 42,390 square feet installed over the existing drinking water reservoir at DC Water's Fort Reno Reservoir.
“To reduce stormwater runoff from the Fort Reno facility, DC Water converted the 1 acre traditional impervious roof on the Reservoir into a green roof,” DC Water says.
Constructed in layers, the roof system is made up of “plants, lightweight soil, and drainage and waterproofing layers that acts as a natural filter by reducing and cooling stormwater runoff through absorption and evaporation. Green roofs create additional green space, reduce the urban heat island effect, provide habitat for birds and pollinators, and help to insulate buildings,” DC Water says.
Here is a video that explains some of the benefits of green roofs.