It seems that when it comes to green building activities, environmental landscaping is slowly and surely gaining traction as a notable talking point… And for good reason. With all the unpredictable weather we’ve been having, it’s never too soon to start thinking, or learning, about stormwater management.


When a big rainstorm happens, rainwater hits the streets and gravity takes it on the path of least resistance, which is our ever increasing number of storm drains. What happens along the way is that the water picks up pollutants and solids including gasoline, oil, trash… even human and pet waste. From there the storm drains take the polluted water to the nearest body of water, stream or ocean.

To help bring it forward even more and prioritize it in your next conversation with stakeholders of your LEED design, here are ten startling facts that will stick with you.Credit: Grand Canyon NPS

  1. 64% of assessed lake acres and 44% of assessed stream miles are not clean enough to support uses such as fishing and swimming.
  2. The impervious surface of a city block can generate five times more runoff than a wooded area of the same size.
  3. In a comparison of two Maine watersheds, phosphorous export – a dangerous element for biodiversity when in high concentration – was 10 times greater in a developed watershed than a forested watershed.
  4. Agricultural runoff is one of the leading sources of water impairment for rivers, streams, estuaries and lakes.
  5. Annually, the U.S. Army Corps of Engineers dredges 83 million cubic yards of sediment linked to pollution sources at a cost of $180 million.
  6. In 2008, the Gulf of Mexico dead zone was estimated to be the same size as New Jersey.
  7. More than one-third of the threatened and endangered species in the US live only in wetlands (one of the most highly impacted areas of poor stormwater management).
  8. Only 15% of rainwater is absorbed by impervious surface, as compared to 50% by natural ground.
  9. 60% of Americans are very worried about “pollution of drinking water,” while 53% are very worried about “pollution of soil and water by toxic waste.”
  10. When impervious space reaches 25% of landmass, a flood that would otherwise be expected only once every 100 years could occur once every 5 years.

With data like this readily available, it’s a wonder that stormwater management isn’t taking center stage more often. So go ahead – make eco-friendly landscaping a stronghold of your future LEED designs and, if ever asked why, just send them here. Shouldn’t be difficult to convert them to believers!


David M. Pratt

David M. Pratt, P.E., CEM, LEED AP is an Energy Management Consultant for Sustainable Climate and Energy Solutions group of MWH Americas, Inc. MWH is the global leader of the wet infrastructure sector. The MWH organization is driving the wet infrastructure sector globally, and we are leading the world in results-oriented management, technical engineering and construction services to build a better world.

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