If you have heard the term green stormwater infrastructure and wondered what exactly it is, a visit to our new YMCA/Sammamish Community and Aquatic Center will give you some examples. Green stormwater infrastructure (also called Low Impact Development or LID), addresses the problem of runoff by using vegetation and soil to infiltrate and cleanse rainwater where it falls as opposed to grey infrastructure, man-made, engineered components of a system that can include gutters, storm sewers, tunnels, culverts, detention basins, pipes and mechanical devices used collectively in a system to capture and convey runoff.
Notice the green roof that will absorb storm water:
A rain harvesting system consists of rain chains that are used in place of gutters and downspouts. The trench drains between the 2 gardens collect and transport the water down the runnel alongside the stairs to the storm water channel on the side of the building. The rain water is stored in the vault under the parking lot in the back of the building. A portion of the water from the storm water vault is used to flush the toilets.
Storm water channel to convey water to the vault.
Notice the bird bath. Between this and the plantings in the back of the building, this looks like the next candidate for certification as a public space wildlife habitat with the National Wildlife Federation!
Notice more rain chains directing water off the roof covering the parking structure steps and into the storm water detention area. Water filters through a fairly deep section of soil and rock and ultimately any excess water goes through a storm water drain to the same vault in the back of the building
Pervious pavement was also used for both the sidewalks and some of the outdoor parking area. It allows storm water to flow through it.
Another way chosen to help deal with storm water runoff is afforestation, the establishment of a forest or stand of trees in an area where there was no forest. Behind the building many native trees and shrubs have been planted down the hillside where it connects to the existing forest of the Lower Commons.
Another example of afforestation in this project is the area below the building in the Lower Commons where for 2 winters, Elby Jones, the city’s volunteer coordinator aided by several native plant stewards and many community volunteers have planted many native trees and shrubs as wetland mitigation for the center and once again assisting with storm water runoff.
Another example of green stormwater infrastructure, rain gardens, are found by the Community Garden in the Lower Commons. This was installed several years ago at the time the parking lot was completed to help deal with stormwater runoff. The plants have filled in nicely over the years!
Not only is green stormwater infrastructure a practical and more natural way of handling stormwater, it is very attractive and creates wildlife habitat.