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

Technical RequirementsInfiltration BasinLong-Term MaintenanceThe local permitting agencies in the Sacramento and South Placer areas require execution of amaintenance agreement or permit with the property owner for projects including an infiltration basin.Check with the local permitting agency about the timing for execution of the agreement. Such agreementswill typically include requirements such as those outlined in Table IB-2. The property owner or his/herdesignee will be responsible for compliance. See Appendix B for additional information aboutmaintenance requirements and sample agreement language.Table IB-2. Inspection and Maintenance Recommendations for Infiltration BasinsActivityMonitor infiltration rate in basin after storm events by recording thedrop in water depth versus time using a calibrated rod or staff gauge.If drawdown time is observed to have increased significantly over thedesign drawdown time, clean, re-grade, and till basin bottom torestore infiltrative capacity. This maintenance activity is expensiveand the need for it can be minimized by preventing upstream erosion.Inspect basin to identify potential problems such as erosion of thebasin side slopes and invert, standing water, trash and debris, andsediment accumulation.If erosion is occurring within the basin, stabilize with erosion controlmulch or mat and seed or re-vegetate immediately.Monitor health of vegetation and replace as needed.Trim vegetation to prevent the establishment of woody vegetation andfor aesthetic and vector control reasons.Remove litter and debris from infiltration basin area.Remove accumulated sediment and re-grade when the accumulatedsediment volume exceeds ten (10) percent of the basin volume. Note:scarification or other activities creating disturbance should only beperformed when there are actual signs of clogging, rather than on aroutine basis.Reconstruct or replace the control measure when it is no longerfunctioning properly.ScheduleSeveral times during first year. Thereafter atthe beginning and end of the wet season.Additional monitoring after periods of heavyrunoff is recommended.As neededAt beginning and end of the wet season.Additional inspections after periods of heavyrunoff are desirable.As neededRoutinely monitor vegetationAt the beginning and end of the wet seasonAs neededAs required for both forebay and basinSee projected lifespan in Appendix B forinformational purposes.Stormwater Quality Design Manual for the Sacramento and South Placer RegionsIB-6 May 2007