Spokane River Watershed Strategies for Point and Nonpoint Source Management to Meet the Most Restrictive TMDL in the Nation

Recognizing the water quality management challenges presented by a sensitive receiving waterbody and the need for a comprehensive watershed approach, the Spokane County Division of Utilities is taking a leadership position in implementing advanced point source wastewater treatment technology and managing a Washington/Idaho bi-state nonpoint source phosphorus management program for the Spokane River. Spokane County plans to manage approximately 8 mgd of wastewater for residential, commercial and industrial customers in the Spokane Valley of Washington with a low effluent phosphorus water reclamation facilities discharging to a receiving water with one of the most restrictive total maximum daily loads (TMDL) in the nation. The Spokane River dissolved oxygen TMDL will require very low effluent CBOD (4.2 mg/l), ammonia nitrogen (0.21 mg/l), and total phosphorus (0.042 mg/l). A new state-of-the-art reclamation facility will produce the highest quality reclaimed water for surface water discharge and for reuse in urban/suburban irrigation of parks, groundwater recharge, wetland restoration, and potentially industrial applications. The reclamation facilities will be coupled with nonpoint source management efforts designed to reduce phosphorus loadings throughout the watershed.