Stormwater management - Southwest Washington

Infiltration bsin

The infiltration basin above still has water more than three days after the rain storm. This could indicate a problem that slows infiltration.

Detention pond

This detention pond is overgrown with vegetation.






Detention pond, infiltration basin, treatment wetland, and wetpond

Maintenance is needed if you see these signs
Bare, exposed soil
• Slopes that are deteriorating
• Sediment that restricts flow or clogs inlet and outlet pipes
• Sediment buildup; the facility is not draining or conveying runoff
• Unhealthy or dead vegetation
• Blackberries or other problem weeds
• Overgrown vegetation
• Holes in berms or slopes
• Leaves, trash and other debris
• Water surface is discolored or has a sheen
• Water stands in infiltration basins or detention ponds longer than 72 hours after rain stops
• Bottoms of slopes show signs of seepage and leaking
• Trees, often alders, growing on the slopes

Checklists for maintenance and recognizing and fixing problems (PDF files)
Detention pond
Infiltration basin
Treatment wetland

Field inlet
Flow control structure/flow restrictor
Debris and access barrier
Access road
Fence, gates, signs