New urban stormwater policies treat rainwater as a resource

U.S. cities are revamping how they handle stormwater to reduce flooding and capture rainfall and recharge aquifers.

New policies reflect a change in mindset from treating stormwater as a nuisance to be quickly diverted away to capturing it as a resource. U.S. urban areas generate an estimated 59.5 million acre-feet of stormwater runoff per year on average, equal to 53 billion gallons a day. That much water is equal to 93% of the country’s total municipal and industrial water use.

In Los Angeles, the nonprofit Trust for Public Land has been removing impervious surfaces in alleys and school grounds and replacing asphalt with natural infrastructure, including trees and pervious surfaces.

In the eastern part of the country where rainfall is more plentiful, cities including New York and Pittsburgh are installing green solutions such as rain gardens and bioswales. Cities are also instituting stormwater fees, charging landowners based on the area of impervious surfaces on a property. More cities are also using permeable pavers for sidewalks and parking lots.

Recharging aquifers via more permeable surface areas not only makes more groundwater available, but it also helps prevent land subsidence that can cause buildings to slowly sink.

New ideas in design and constructability are radically changing how metal systems are used as roofing for commercial and institutional buildings. Behind the investment in these new kinds of expressions and construction approaches is a growing interest in improved performance and reduced environmental impact. Metal roofing systems can cut cooling and heating loads significantly, according to the EPA.