− | Pre-treatment structures are most cost effective when they slow down incoming flows, collect sediment for easy clean out, and slowly release water to the bioretention facility mitigating erosion. [[Pretreatment]] structures/strategies can include [[curb cuts]], [[Aggregates]], proprietary devices like filters or hydrodynamic separators, vegetation, concrete sumps, membrane filters, overland flow sumps, etc. | + | Pre-treatment structures are most cost effective when they slow down incoming flows, collect sediment for easy clean out, and slowly release water to the bioretention facility mitigating erosion. [[Pretreatment]] structures/strategies can include [[curb cuts]], [[Aggregates]], proprietary devices like filters or [[Oil and Grit Separator|hydrodynamic separators]], [[vegetation]], [[Flow through riser|concrete sumps]], [[Pretreatment#Concentrated underground flow|membrane filters]], [[Pretreatment#Concentrated overland flow|overland flow sumps]], etc. |