Routine HOA maintenance, like mowing and debris removal, is vital to the proper operation of the detention pond, and needs to be done on a frequent basis. Non-routine HOA maintenance, like slope stabilization and sediment removal, will probably be more on an annual basis. Every pond is different in the size, type and characteristics of the tributary area that contributes runoff to the pond, as well as the location of the pond within the development. A pond serving a large commercial district will likely require more maintenance than one serving an established neighborhood, and a pond in a prominent location in the development will require more frequent collection of trash. Maintenance considerations for a wet pond will need to focus on floating litter, scum and algal blooms, shoreline erosion, possible unpleasant odors and mosquitoes, as well as more difficult sediment removal. Maintenance considerations for a dry pond will concentrate more on mowing to control the vegetation and frequent removal of the trash, debris and clippings that may clog the outlet/trash rack. Maintenance will always be needed; if maintenance is not done, or not done frequently enough, or properly, a false sense of security exists for the pond’s temporary storage abilities during a large storm event, and its pollutant removal abilities during a typical runoff event. Routine maintenance includes:
- Inspections: Periodic scheduled inspections with a specified checklist, and inspections after major rainfall events, to check for obstructions/damage & to remove debris/ trash.
- Vegetation Management: Mowing on a regular basis to prevent erosion or aesthetic problems. Limited use of fertilizers and pesticides in and around the ponds to minimize entry into pond and subsequent downstream waters.
- Trash, debris and grass clippings Removal: Removal of any trash causing obstructions at the inlet, outlet, orifice or trash rack.
- Mechanical Equipment: Inspection & repair of any valves, pumps, fence gates, locks or mechanical components.
- Structural Component: Inspection of the outlet, inlet, orifice, trash rack & trickle cannel.
Non-routine maintenance includes:
- Bank erosion/stabilization: It is critical to keep effective ground cover on all vegetated areas. All areas not vegetated should be re-vegetated and stabilized immediately
- Sediment removal: Every year, the accumulated sediment should be removed from the bottom of the outlet structure and the pond depths checked at several points. If the depth of the accumulated sediment is greater than 25% of the original design depth, sediment should be removed.
- Structural Repair/Replacement: Eventually the outlet structure or other structural components like the trickle channel or trash rack will need repair or replacement.
- Spill Clean-up: Removal of contaminated soil.