Redmond Bioretention Monitoring

Filtration media in bioretention facilities is critically important to their treatment effectiveness. Our media development and monitoring work leads to improved media mixes and increases pollutant quantities removed from stormwater. We helped the City of Redmond obtain funding and monitor effectiveness of one of the first Redmond facilities, constructed as part of the 185th Ave NE extension. We developed a scientifically defensible automated sampling and quality plan; installed automated sampling equipment, weirs, pressure sensors, and cellular telemetry; and custom programmed dataloggers. We learned that the media was exporting copper and nutrients in addition to treating other pollutants.  This surprising result led to improved bioretention media specifications, and improved protection of Puget Sound water quality.