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