Dispersion Areas

Dispersion Areas are vegetated areas designated to receive stormwater runoff from impervious surfaces such as rooftops, walkways, and driveways.

Stormwater runoff is directed from these surfaces by a downspout with a splash block, or a flow spreader, which distributes the stormwater runoff into a Dispersion Area.

Once in the Dispersion Area, the runoff flows through the vegetation and soil which is known as infiltration. During infiltration, the runoff is filtered preventing pollutants from entering the storm drain.
 

Benefits

Dispersion Areas may offer the following benefits:

  • Reduces runoff volume and peak flows 
  • Remove pollutants from stormwater 

 

What does your Dispersion Area look like?

Typical Dispersion Areas configuration can include:
 

  1. Inlet: The entry point for water flow into the Dispersion Area.
  2. Impervious Surface: Hard surfaces like rooftops, driveways, or walkways that generate stormwater runoff.
  3. Flow spreader: A device or feature that evenly distributes stormwater runoff across the Dispersion Area.
  4. Vegetated area: Designated to receive stormwater runoff from impervious.
  5. Native soil or amended soils: Soil that supports infiltration.
     

Target Pollutants

  • Trash
  • Debris
     

Inspection & Maintenance Activities

Activity Suggested frequency/schedule
Inspect for accumulation of sediment, litter, or debris Montlhy
Inspect for poor vegetation establishment, dead or diseased vegetation or overgrown vegetation Monthly
Inspect for proper drainage and erosion After significant rain events
Check for signs of mosquito breeding Monthly and after significant rain events


BMP Fact Sheets in PDF format

Structural BMP Outreach Flyers (Educational Resources Page)
 

Contact

  (858) 495-5323

  BMP.Program@sdcounty.ca.gov

 

 

Maintaining My Structural BMP Home Page