Evergreen State College, The
OP-23: Stormwater Management

The Evergreen State College is located on the Cooper Point Peninsula, with extensive waterfront on Eld Inlet. The college minimizes its impact on the inlet by maintaining a largely undeveloped, heavily forested campus. The undeveloped portion has been set aside as reserves—Ecoforest/Ecoagriculture area, Old Forest Area, Geoduck Beach and Grass Lake wetland area—which are key to the health of the campus watershed. The campus core is the location of the highest number of impervious surfaces on TESC property. Green strips, small gardens, green roofs on the Library and Seminar II buildings, pervious paving, bioswales and native trees mitigate the effects of impervious surfaces. Similarly, storm water detention tanks at Seminar II and the College Activities Building mitigates the high runoff from significant storms. Other impervious surfaces include campus parking lots. Joint oil-water separators release storm water into a Red Alder grove before entering Eld Inlet. Another oil-water separator releases into a drainage ditch that runs into Snyder Creek. Snyder Creek receives a large volume of campus storm water runoff, as does the Red Alder grove, but illicit discharge to that system is reduced through the use of pervious pavement, oil-water separators, bio-swales and dense vegetation. These measures serve to filter many of the potential pollutants out before they reach the Eld Inlet, and in this way TESC works constantly to preserve water quality in the Puget Sound.

The Seminar II (LEED Gold) and Library buildings have multiple vegetated roofs. (http://www.evergreen.edu/news/archive/2005/07/greenroof.htm)

Porous paving was installed during a parking lot expansion (required by local code during the construction of the new Seminar II building) in 2004.

Though wetland areas exist on campus, there are no natural ponds or lakes, the campus sits on and drains into Puget Sound. Evergreen uses stormwater retention tanks rather than retention ponds.

The Seminar II building has stone swales in the central court and various sides to mitigate rainwater runoff.

Vegetated swales have been installed around the residence halls and the newly renovated College Activities Building to mitigate storm water runoff.

Evergreen has two stormwater retention tanks/cisterns with metered release. The Seminar II building tank is 18,000 cubic feet (135,000 gallons) and another has a 35,000 gallon capacity under the College Activities Building.