Problem

Many roofs contribute massive amounts of stormwater runoff to the creek because the downspouts are sent directly to the street. In a 1- inch rainfall, a 3,000 square-foot roof can shed 1,800 gallons of stormwater. Across a city, thousands of rooftops create millions of gallons of stormwater runoff that fill the creeks in an unnatural and harmful way. This runoff also carries with it any pollutants from the roof itself, such as animal droppings or grit from roof shingles.

Stormwater flowing into storm drain

Stormwater flowing into storm drain
Image source: Wikipedia, Robert Lawton

Solution

Catch and treat the runoff where it falls by adding a green roof to your house or garage. Green roofs are the gold standard for urban stormwater management, consisting of a layer of vegetation and soil installed on top of an impermeable layer on an existing roof. In addition to reducing stormwater runoff and pollutants, green roofs may also: reduce roofing maintenance, improve energy efficiency, reduce the urban heat island effect, provide habitat for wildlife, and improve air quality. While green roofs have been used for centuries in Europe, modern versions are engineered to be used on existing rooftops. However, green roofs usually require professional engineering to ensure that the integrity of the roof is not compromised by the weight of the material and retained water.

Green Roof in Durham, NC

Green Roof in Durham, NC
Image source: Xeroflor America