Bioretention systems are very effective in mitigating the adverse effects of stormwater, especially its effects on salmon species living in downstream waters. However, bioretention systems have some chronic challenges that the LID program seeks to understand further and find solutions to. We are working on improving the types of mixes, design features and amendments used in bioretention systems.

Rain gardens at WSU Puyallup

16 experimental bioretention cells, located at WSU’s Puyallup Research and Extension Center, were refurbished and four replicates each were topped with three different types of mulch–arborist chips, medium bark mulch, nugget mulch, and no mulch (study control).

Flooded mesocosm with 4 plants

Study is intended to compare the side-by-side pollutant removal and hydraulic performance of media controlled bioretention mesocosms to outlet controlled bioretention mesocosms.

column study in greenhouse

Column study that evaluated the treatment of highway stormwater runoff in terms of the removal of Polycyclic Aromatic Hydrocarbons (PAHs) and Fecal Indicator Bacteria (FIB).