Stormwater is runoff water from rain that flows off rooftops, paved areas, bare soil, and lawns, gathering from puddles, to ditches, to streams, and flowing into our lakes and rivers. Along the way, stormwater picks up pollutants – including automobile fluids (such as oil, gasoline, and antifreeze), pesticides, fertilizers, sediment, pet waste, and litter – and deposits them into the rivers and lakes that supply our drinking water. Fertilizers contain nitrogen and phosphorous, which promote algae growth. Excess algae combined with sediment and toxic chemicals severely damage water quality, killing aquatic life and making the water unfit to drink. Not only are we drinking and swimming in stormwater runoff, but we pay the price of additional chemicals and treatments necessary to make our water safe to drink.
New development increases stormwater runoff into the lakes and rivers that supply our water. The more impervious surfaces – including sidewalks, streets, and rooftops – that exist, the more stormwater runoff results. In addition to picking up and carrying more sediments and pollutants, this increased velocity of stormwater erodes stream banks, further contributing to water degradation. Moreover, allowances for developers to emit more than the annual state-permitted amount of nitrogen into the watershed degrades our water supplies even more. Drinking water treatments and stream restorations are costly (and usually paid for with taxpayer money) and could be prevented by better stormwater management.
To protect existing and future drinking water supplies, we must enact stricter stormwater regulations, create incentives to capture and reuse stormwater, and increase land conservation and stream restoration. Considering the concurrent problems of water quantity and quality, improving stormwater practices can help us address both issues at once. Reducing stormwater pollution improves water quality; using stormwater for irrigation and other non-potable purposes extends our limited groundwater supply; and increasing infiltration of stormwater enlarges our water supply. With appropriate stormwater management and land development practices, stormwater can be an asset rather than a liability.