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No.5—Catch Basins <br /> Maintenance Defect Conditions When Maintenance is Needed Results Expected When <br /> Component V Maintenance is performed <br /> General Sediment& Sediment,trash,and/or other debris material is No sediment or debris is <br /> Debris located immediately in front of the catch basin located immediately in front <br /> opening or is blocking inletting capacity of the of catch basin or on grate <br /> basin by more than 10%. opening. <br /> Sediment,trash,and/or other debris material No sediment or debris is in <br /> (located in the catch basin)exceeds 60 percent of the catch basin. <br /> the sump depth as measured from the bottom of <br /> basin to invert of the lowest pipe into or out of the <br /> basin,but in no case less than a minimum of six <br /> inches clearance from the debris surface to the <br /> invert of the lowest pipe. <br /> Sediment,trash,and/or other debris material Inlet and outlet pipes are free <br /> located in any inlet or outlet pipe is blocking more of sediment and debris. <br /> than 1/3 of its height. <br /> Dead animals or vegetation that impair catch basin No dead animals or <br /> function or that could generate odors that could vegetation are present within <br /> cause complaints or dangerous gases(e.g., the catch basin. <br /> methane). <br /> Structure Top slab has holes larger than 2 square inches or Top slab is free of holes and <br /> Damage to cracks wider than 1/4 inch cracks. <br /> Frame and/or (Intent is to make sure no material is seeping into No water and/or soil is <br /> Top Slab the catch basin). seeping into the catch basin <br /> Frame not sitting flush on top slab,i.e.,separation Frame is sitting flush on the <br /> of more than 3/4 inch of the frame from the top riser rings or top slab and <br /> slab.Frame not securely attached firmly attached. <br /> Fractures or Cracks wider than 1/2 inch or evidence of soil Catch basin is replaced or <br /> Cracks in Basin particles entering the structure through the cracks, repaired to design standards. <br /> Walls/Bottom or qualified maintenance or inspection personnel <br /> determine that the vault is not structurally sound. <br /> Grout fillet has separated or cracked wider than Pipe is regrouted and secure <br /> 1/2 inch and longer than 1 foot at the joint of any at basin wall. <br /> inlet/outlet pipe or any evidence of soil particles <br /> • entering catch basin through cracks. V <br /> Settlement/ Settlement of misalignment of the catch basin Catch basin is replaced or <br /> Misalignment causes a safety,function,or design problem. repaired to design standards. <br /> Contaminants Any evidence of oil,gasoline,contaminants or Contaminants or pollutants <br /> and Pollution other pollutants are removed. <br /> Note:Coordinate removal/cleanup with local <br /> and/or state water quality response agency. <br /> Access Hole Cover Cover Not in Cover is missing or only partially in place.Any Catch basin cover is fully in <br /> Place open catch basin requires maintenance. place <br /> Locking Locking mechanism cannot be opened or lock Mechanism or lock bolts <br /> Mechanism Not bolts cannot be removed by one maintenance open with proper hand tools. <br /> Working person with proper hand tools. <br /> Cover Difficult One maintenance person cannot remove lid after Cover can be removed and <br /> to Remove applying normal lifting pressure with proper hand reinstalled by one <br /> tools.Intent is keep cover from sealing off access maintenance person with <br /> to maintenance, proper hand tools. <br /> January 2016 Snohomish County Drainage Manual Volume V-Runoff Treatment BMPs 31 <br />