On a rainy Saturday in mid-May, People for Puget Sound’s Jamie Wine led the first of a series of tours of Eastside watersheds, along with co-host Preston Glidden of Sustainable Bellevue. Ponds, creeks, and wetlands as well as three lakes headlined the itinerary which focused on the latest in approaches to stormwater treatment.

The first stop was Kelsey Creek Shopping Center, where the old Kmart and its parking lot cover the flowing water below, visible through grates. Plans are in place to convert the building, and rather than “daylighting” the creek, which would require a 150-foot-wide green buffer zone, the developer has instead agreed to mitigate by improving the Larsen Lake wetland just to the south.

The tour explored the creek’s entrance to the wetland, which features a large blueberry farm, before making a detour over to the Lewis Creek watershed and the next stop, Lakemont Park.

The park is the site of an extensive and innovative stormwater treatment system for runoff from the recent developments on lower Cougar Mountain. The system includes sand pits for filtering the water, as well as a large retention pond for overflow. The combination creates an artificial wetland which hosts ducks, swallows and frogs, and cleanses the water as it joins Lewis Creek en route to Lake Sammamish.

The tour next headed back Kelsey Creek and the Wilburton Trestle to view the spawning grounds of Sustainable Bellevue’s unofficial mascot, the peamouth minnow. Hundreds of these trout-sized fish have returned several times this season to the lower reaches of Kelsey Creek. They swim up the fish ladder located just west of I-405 at Southeast Eighth at the entrance to the Mercer Slough, and Lake Washington, the final stop for the tour.

The tour wound up at the Mercer Slough Environmental Center, a state-of-the-art green facility, which provides a resource center for environmental issues as well as examples of green architecture and creative runoff treatment. These include permeable cement for sidewalks, and “gabions” (rocks enclosed in wire fencing to make permeable walls), to swales and rain gardens with native plants, all of which allow stormwater to filter elements such as lead and arsenic through the soil rather than pour them directly into the water table or streams.www.pacsci.org/slough/

More information is available at sustainablebellevue.ning.com