FROM DROUGHTS TO FLOODS?
Impervious surfaces – such as roofs, roads, and parking lots – generate between 5 and 16 times the stormwater runoff of that generated in natural/unpaved areas. That’s a lot of water. In the Puget Sound region of the Pacific Northwest, for example, for every 1 acre of paved surface, 1 million gallons (133, 681 cubic feet) of stormwater runoff enters the Sound every year. With millions of miles of concrete and metal and asphalt pipes, ditches, roadways, parking lots, and roofs in every city across the country…hundreds of millions of gallons of polluted stormwater flow through our sewer systems – in many cases far exceeding capacity – and enter our waterways annually. Which explains why, when so many places seem to have so little water, they flood when the storms come. And because the water is traveling across impervious surfaces, it heads straight to the nearest lake or river instead of recharging our groundwater supplies, which exacerbates future drought conditions, diminishes the quality of available fresh water, and increases costs for treatment and against industries that depend on clean water to survive. Implementing low-impact design and green infrastructure captures millions of gallons of stormwater annually, saving cities and property owners an awful lot of money in property damage and flood control.