Fisher Creek Campus

ELS worked with project engineers to design and permit a wetland mitigation project that incorporated stormwater treatment in accordance with the Stormwater Management Manual for Western Washington for the new Corporate Campus of Fisher Investments, located in the Grass Valley area of Camas, Washington.  Several elements combining wetland and habitat mitigation were integrated with stormwater treatment and detention.  First, existing wetland swales were avoided where possible among the proposed parking areas, allowing treated runoff to flow through these wetlands for additional natural treatment.  Second, rain gardens were incorporated into the landscape areas of the parking lots to facilitate drainage and treatment.  The rain gardens were planted with native wetland and riparian species, capable of handling “flashy” storm runoff events.  Third, a large down slope wetland complex with existing road crossings was utilized to enhance the detention capacity of wetland, without sacrificing its wetland function.  This was accomplished through designed structures placed at the previous road crossings to detain larger storm event flows.  ELS analyzed the existing wetland for potential impacts of longer duration flooding.  As a general rule, the existing wetland was dominated by native species such as Oregon ash, black cottonwood and spiraea, species which can withstand prolonged flooding.  We also specified additional native plantings in areas to reduce coverage by the invasive reed canary grass.  This approach of combining wetland enhancement with stormwater treatment was reviewed and approved by biologists from the Washington Department of Ecology, who were supportive of this innovation.  All permits were acquired for this project, including Section 404 (Corps), Water Quality Certification (Ecology), and a Critical Areas permit from the City of Camas.