This Seattle-based cement manufacturer discharges industrial stormwater to the Duwamish East Waterway, a source control area identified as part of the overall cleanup process for the Lower Duwamish Superfund Site. Clear Water was called to design and install a permanent chemically enhanced sand filtration (CESF) system to treat turbidity and high pH below surface waterbody benchmarks. Since system installation, the client has drastically reduced illicit discharge for both high pH and turbidity. In addition to the required monitoring for pH and turbidity, analytical samples are regularly taken to determine oil and grease content as well as arsenic, copper, mercury, and zinc levels in accordance with the Industrial Stormwater General Permit (ISGP). To date, the site complies with the ISGP, discharging effluent water below all benchmarks.