Stormwater Quality Design Manual (May 2007) - City of Sacramento ...

Runoff Treatment Control Measure Fact SheetWater Quality Detention BasinsLong-Term MaintenanceRegional detention basins usually will be maintained by the local agency. A long-term maintenance plan(i.e., adaptive management plan) shall be prepared by the developer/owner and approved by the localagency prior to acceptance of the basin.If the basin will be privately maintained, the local agencies will require execution of a maintenanceagreement with the property owner prior to final acceptance of a private development project, includingacceptance of the water quality basin. Check with the local permitting agency about the timing forexecution of the agreement. The maintenance agreement will typically include requirements such as thosein Table DB-5. The property owner or his/her designee will be responsible for compliance. See AppendixB for additional information about maintenance requirements and sample agreement language.Table DB-5.Inspection and Maintenance Recommendations for Water Quality Detention BasinsActivityInspect the facility for needed maintenance.Remove trash and debris.Remove sediment, debris and litter that accumulates in thesediment forebay (To clean the sediment-collection area for a wetbasin, it may be necessary to drain, pump or partially drawdown thepond area.)Remove sediment that accumulates in the concrete low flowchannel.Control weeds and invasive plant species.. Carefully weed areas toavoid removing the native species .Use integrated pest management (IPM)Irrigate plantsReplant any bare areas. Investigate why the die-off occurred andtake remedial action to correct the problemHarvest vegetation around the perimeter of permanent ponds sothat mosquito fish are not impeded by thick vegetation.Harvest vegetation in channelsWhere permitted by the Department of Fish and Game or otheragency regulations, stock wet ponds with mosquito fish (Gambusiaspp.) to enhance natural mosquito and midge control.Control any erosion by redirecting or dissipating the water source. Ifnecessary, recontour, mulch, and/or reseed.Reconstruct or replace the control measure when it is no longerfunctioning properly.ScheduleTwice a year.At least twice a year.Every 3 to 5 years or when 6 to 12 inches haveaccumulated, whichever comes first.AnnuallyRegularly during the first 2 years and then asneededAs neededAs needed during the establishment period(see construction considerations) and duringperiods of droughtIn the event of extensive die-offEach summer. More frequently if required bylocal vector control agencies.As neededAs neededWhen there are signs of erosion, includinggullies, rills and evidence of sheet erosion.See projected lifespan in Appendix B forinformational purposes.Stormwater Quality Design Manual for the Sacramento and South Placer RegionsDB-12 May 2007