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Rain Gardens —160 FTE Labor Hours required; 2 FTEs required Low Priority. Typical maintenance <br />activities include, pruning (spring/fall), replacing plants, adding mulch, pulling weeds, removing <br />sediment, removing trash and inspection. Per the Municipal Separate Storm Sewer System (MS4) <br />Permit, inspection of rain gardens should occur annually. Public Works needs to develop an updated rain <br />garden location map and create a plan for future maintenance. Current maintenance is ordered "as <br />needed", addressed with the Street Maintenance Plan areas or at rain gardens in highly visible areas. <br />Surface Water Ponds —160 FTE Labor Hours required; 2 FTEs required Medium Priority. Maintenance <br />activities include removal of excessive vegetation, removal of trash/debris and removal of <br />sedimentation or dredging. Adequate access must be provided for inspection, maintenance, and <br />landscaping upkeep, including appropriate access needs for equipment and vehicles for when more <br />extensive repairs are required. Primary issues we look for during inspections is clogging of the inlets and <br />outlet, weir structure condition, erosion and gulley formation, sedimentation build up and undercut of <br />adjacent roadways or trails. Per the MS4 Permit, inspection of surface water ponds should occur once <br />with each permit cycle which is typically 5 years. Public Works needs to develop an updated surface <br />water pond map and create a plan for future maintenance and rehabilitation projects. Currently, pond <br />maintenance and rehabilitation is included in the City's PMP projects. Pond elevation control points <br />were installed at ponds dredged during the 2024 PMP. <br />Outfall condition Inspection — 80 FTE Labor Hours required; 1 FTEs required High Priority Following the <br />MS4 Permit, the City is required to inspect every municipal outfall (outlet/inlet) once with each permit <br />cycle which is typically 5 years. Arden Hills currently has 439 outfalls inventoried so we will inspect <br />roughly 90 structures each year. Through inspection, a report is created to address condition, repairs <br />needed, odor detection or inflow & infiltration concerns. <br />Grit Chambers —180 FTE Labor Hours required; 3 FTEs required High Priority. Public Works inspects and <br />cleans every grit chamber annually. Grit chambers can be in the form of a baffled structure, separated <br />tanks or a simple sump style. It is important to clean these structures more frequently as they are an <br />important factor in promoting water quality by separating sediment and other debris before reaching <br />our water bodies. These are also typically installed directly upstream from ponds to help reduce prolong <br />the time needed for costly dredging activities. Public Works is currently updating inventory of existing <br />grit chamber structures. <br />Open Ditches & infiltration basins 120 FTE Labor Hours required; 3 FTEs required High Priority. follow <br />the same maintenance activities. Inspection for repairs or erosion issues, remove debris and vegetation <br />removal. <br />Catch Basins — 240 FTE Labor Hours required; 3 FTEs required High Priority. Public Works conducts full <br />structure inspections every 5 years to address any repair needs. Issues to look for are inflow & <br />infiltration, settling of surrounding pavement or curb, cracking of interior structure concrete, drain tile <br />cleaning and any blockage with flow. <br />Storm sewer mainlines —120 FTE Labor Hours required; 2 FTEs required High Priority. Inspection via <br />televising camera is conducted on an as -needed basis. Full inspections are completed prior to Pavement <br />Management Program (PMP) projects to identify any structural repairs needed. Ajurisdictional map <br />needs to be created that identifies City/County/MnDOT/Private ownership of storm sewer. <br />W <br />