Report: Environmental protections successful at Urban Planned Developments in King County

12-year-long monitoring program of numerous environmental conditions shows stormwater management systems effective in mitigating housing developments

A long-term monitoring program of two Urban Planned Developments (UPDs) in unincorporated King County shows that measures taken to protect water quality, fish and wildlife, and other environmental features have been successful.

The report was issued by the County’s Water and Land Resources Division. Available at http://your.kingcounty.gov/dnrp/library/2011/kcr2162_2008.pdf, the report notes that stormwater management actions required as mitigation for the Trilogy and Redmond Ridge UPDs worked as designed.

Monitoring was done in coordination with the University of Washington, the King County Department of Development and Environmental Services and UPD developer, the Quadrant Corporation.

The collected data related to numerous environmental factors, including rainfall, water quality, stream channel stability, stream and wetland hydrology, wetland vegetation, groundwater quantity and quality, and evaluation of fish, amphibian and aquatic insect community composition.

The Trilogy and Redmond Ridge UPDs cover 2,126 acres on Novelty Hill between Redmond and Duvall in eastern King County.

To minimize changes to streams, wetlands, and groundwater, these UPDs maintained natural buffers around streams and wetlands that average 200 feet wide, and also constructed more than 50 stormwater management facilities that assist in controlling both stormwater quality and volumes. Learn more about the UPDs at http://www.kingcounty.gov/property/permits/info/SpecialInterest/UPDRR.aspx.

Related information

Stormwater services and information

King County Water and Land Resources