Bioretention Studies

Reports on Biorention from the City of Redmond

Analysis of Bioretention Soil Media for Improved Nitrogen, Phosphorus, and Copper Retention

Monitoring data from several studies conducted in the western Washington region (Herrera2014a, 2015) indicate that some pollutants are exported from bioretention systems using the default bioretention soil media (BSM), most notably nitrogen (N), phosphorus (P), and copper (Cu). To address this concern, Herrera Environmental Consultants (Herrera) implemented a study in partnership with Kitsap County to improve BSM performance for the capture and retention of these pollutants. This study was funded by the Washington State Department of Ecology (Ecology) through the Municipal Stormwater Grants of Statewide and Regional Significance program (2013–2015 biennium)...

City of Redmond Six Swale Biroretention Monitoring

This study occurred in parallel to the Kitsap Column Study. It included six different full scale bioretention swales designed for the area that drain to them. Flow weighted composite sampling (TAPE style sample collection).

185th Avenue NE Bioretention Stormwater Treatment System Performance Monitoring
This was the first TAPE study of bioretention that exposed some concerns about the 60/40 mix and the constructability of bioretention with (at the time) current design guidance. Many design issues have been addressed with the current 2012 SWMMWW.