Bio-swales offer a relatively simple solution to the challenge of increasing run-off from our city's paved surfaces. A well designed bio-swale will decrease the volume of water that heads to the waste water treatment plant, increase the percolation of water into the aquifer, provide habitat for insects and birds, decrease the amount of contamination flowing into Paradise Creek and Hog Creek, all while providing a more aesthetically pleasing environment for City residents. This is efficiency at its best.
Green roofs offer more opportunities for onsite storm water mitigation and also offers energy savings to the building's residents. According to the American Society of Landscape Architecture's building in Washington DC has compiled data on the performance of their green roof.
Green Roof Performance Data
- Roof produced a 10 percent decrease in building energy use over the winter months.
- The temperature on the green roof on the hottest summer days can be as much as 43.5 degrees cooler than conventional roofs on neighboring buildings.
- During a 10–month monitoring period, ASLA’s green roof prevented 27,500 gallons of stormwater — nearly 78 percent of all precipitation hitting the roof — from flowing into D.C.’s overburdened sewer and stormwater system.
- Water quality testing shows that the water runoff contains fewer pollutants than typical water runoff. Most significantly, the roof is reducing the amount of nitrogen entering the watershed.
- Except during repeated heavy rains, the roof only creates runoff during rainfalls of more than one inch.
A landscape architect can offer municipalities the opportunity to deal with storm water run-off onsite, reducing the costs of installing miles of pipe, repairing these pipes later down the road and upgrading expensive waste water treatment plants. Aside from all of these practical reasons residents will have the benefit of living in a beautiful community...which may be the best reason of all. Stay tuned for a future blog on the benefits of nature to human health and happiness.