MHFD and SEMSWA initiated the stream stabilization design for a reach of Willow Creek, with the goal of water quality improvements incorporating storm sewer outfall treatment. Through collaboration with CH2M, Valerian developed final designs for four stormwater outfall structures to provide water quality treatment via multi-stage filtering, nutrient uptake and infiltration of stormwater runoff from the surrounding parking lots and development.
The project features a boulder water quality rundown that captures and partially treats a portion of the nearby parking lot’s drainage. The innovative tiered cell design includes placement of engineered water quality growing media and strategic plantings to slow runoff flows and encourage infiltration before entering Willow Creek. The rundown aesthetically fits into the natural channel design and provides an amenity for the surrounding neighborhood.