Putting a “LID” on Harmful Stormwater Runoff

You may not think of parking lots and suburban lawns as sources of pollution, but when it rains, they might as well be Superfund sites: petrochemicals, heavy metals, and toxic levels of nitrogen and phosphorous from fertilizer can enter nearby waterways at high concentrations, harming local ecosystems. During heavy storms, runoff from roofs, impervious pavement, and compacted soil can also cause erosion and flash floods and can sweep dangerous levels of silt—or even human waste and concomitant pathogens—into waterways.

Green infrastructure and other strategies related to low-impact development (LID) aim to prevent all these detrimental effects of runoff, whether during a light rain or a heavy storm. Integrated into landscape architecture to mimic natural hydrology, green infrastructure decreases runoff quantity and improves rainwater quality by performing several interrelated functions.