9424 18TH AVE W 2018-01-02 MF Import

SECTION X- Maintenance & Operations Requirements The improvements p�oposed for treatment and attenuation of runoff are intended to be ultimately free of extraordinary maintenance needs. Rain Gardens The rain gardens integrate into the front-yard landscaping for the homes, and as such will be maintained by the homeowners. Typical maintenance would involve raking of accumulated leaves, removal of litter, replacement of dead plants and remaving clogs from the overflow grate. Compost material in the rain gardens will require total replacement after approximately 10 years. This ensures that permeability and water quality benefits are maintained throughout the life of the system. A detailed description of the importance and function of these facilities along with recommended maintenance will be provided to the homeowner's association. Compost filter berms The compost filter berms, which provide additional water quality treatment and flow attenuation, are designed to become part of the natural environment of the wetland buffer. The compost filter berms mimic the un-even, hummocky ground of a mature forest floor. The berms may experience post-construction settlement as the compost-amended soiis reach equilibrium density. Posts placed within the core of the berm provide an indicato� of the design elevation of the berm. Additional compost may need to be added in the first years to maintain the design elevation — after that, accumulation of naturally occurring decaying vegetation (leaves, needles, etc.) will maintain the berms. The overflow weirs will be constructed as lightly armored low points in the berms. As the ground cover on the berms develops, the risk of erosion during any overtopping that may occur diminishes. Rodent holes and/or digging from dogs pursuing said rodents is the greatest threat to the berms. Placernent of plastic webbing below the top layer of compost and seed while allowing rodents to pas� will prevent dogs from digging (see detail on plans). Bubble-up Distribution Basin The bubbie-up basins that disperse runoff from groundwater, roof and footing drains require periodic inspection of the armoring and removaf of sediment from the sump of HEARTHSTONE LANE 17 DRAINAGE REPORT APRIL 2006