6/22/2023 0 Comments Green roofs seattle![]() In doing so, it cuts down on the amount of flooding and reduces the polluted runoff that reaches sewers, streams, rivers, lakes, and oceans. Green infrastructure encompasses a variety of water management practices, such as vegetated rooftops, roadside plantings, absorbent gardens, and other measures that capture, filter, and reduce stormwater. Here’s a look at what green infrastructure is, what it does, and why we should invest so much green paper in it. As an alternative to traditional water management systems, green infrastructure offers a cost-effective solution to many of our water woes, including how to handle flooding and stormwater pollution. The country’s urgent infrastructure needs also present a major opportunity. Environmental Protection Agency (EPA) estimates that upgrading our stormwater and other public wastewater systems will require at least $150 billion in investments over the next two decades. Not surprisingly, in 2021, the American Society of Civil Engineers bestowed a lowly D letter grade on U.S. In many urban and suburban areas, this runoff causes significant flooding as well. waterways from city sewer systems every year, polluting the environment and drinking water supplies. An estimated 10 trillion gallons of untreated stormwater runoff, containing everything from raw sewage to trash to toxins, enters U.S. The critical systems we rely on nationwide endure chronic overuse and underinvestment, including our stormwater management systems. The period included several extreme dry and wet periods.From highways to bridges to airports, America’s infrastructure is in dire need of a face-lift. The weather during the 18-month data collection period July 2005 to January 2007 recorded 55.4 inches of cumulative rainfall, which was around average for Seattle. The test plot planting media they used were sedums and sempervivums. The engineers also found that the drainage layer was very important, and that while cellular drainage mats are often used, aggregate drainage layers can perform better and may be cheaper. For Seattle’s wet climate, they found that four to six inches was the best thickness for the vegetation. But even in the wet climate of Seattle, the roofs were able to rebound between events and absorb the rainfall. Therefore, every gallon of rainfall eliminated at the building site by a green roof is a gallon that does not require treatment with chemicals, processing, etc.”ĭespite absorbing so much rain run-off, the green roofs were not able to reduce it enough to eliminate the need for detention tanks. cities), much of this system is a combined sewer, which sends rainfall combined with sewage to wastewater treatment plants. described the environmental advantages of reducing the volume of run-off in combined sewer systems: “Every inch of rain (or gallon of runoff) eliminated by a green roof is runoff that does not enter the municipal storm drainage collection system. In an interview in the company’s newsletter, Drew A. The results showed that the green roofs reduced the rainfall runoff by between 65% to 94% - much more than had been modeled. The final report by Magnusson Kelmencic Associates is the result of over 1.5 million measurements of data gathered from five green roof test plots around Seattle’s downtown area. ![]() ![]() Engineers in Seattle have completed an 18-month evaluation of green roofs to see how well they actually perform. ![]()
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