Recessed planter beds are sunken planting areas with inlets to divert storm water into the submerged trenches. Good for parking lot retrofit.
Benefits & Problems Addressed
Stormwater runoff reduction: Recessed beds handle rainwater that otherwise would drain untreated into curbs & gutters into local waterways.
Aesthetics: new landscaping improves the appearance of otherwise flat parkign lots.
Water for landscaping: water naturally flows into landscaping, lessening the need for irrigation and potentially enhancing growing conditions.
Tips & Techniques
Install curb inlets: install inflow cut-outs in planter areas (new and retrofit) locared in parking lots and sidewalk planters
Landscape design considerations: landscaping needs to be sunken rather than the conventional metod of mounding soil up. Install rocks or gravel at the inlet location to slow the erosive effects of water. Soil amendments can be used to increase soil permeability if necessary.
Hot Buttons: Increasing vegetated aras can reduce number of parking spaces. Trash and weed removal, as well as other maintenance needed. In cases of extreme rainfall, sunken beds may not handle the total volume of water.
San Mateo County Sustainable Green Street adn Parking Lots Guidebook (2009)
Green Parking Lot Resource Guide, USEPA