7800 EVERGREEN WAY HYUNDAI Drainage Report 2025-04-28

Table V-A.3: Maintenance Standards - Closed Detention Systems (Tanks/Vaults) (continued) Maintenance Per- Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Component formed Cover Not in Place Cover is missing or only partially in place. Any open manhole requires maintenance. Manhole is closed. Manhole Mechanism cannot be opened by one maintenance person with proper tools. Bolts into frame have less than 1/2 inch of Locking Mechanism Not Working thread(may not apply to self-locking lids). Mechanism opens with proper tools. Cover Difficult to Remove One maintenance person cannot remove lid after applying normal lifting pressure. Intent is to keep cover from sealing off Cover can be removed and reinstalled by one access to maintenance. maintenance person. Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, misalignment, not securely attached to structure wall, rust, or cracks. Ladder meets design standards. Allows main- tenance person safe access. Catch Basins See Table V-A.5: Maintenance Standards-Catch See Table V-A.5: Maintenance Standards- See Table V A.5: Maintenance Standards Catch Basins Basins Catch Basins Table V-A.4: Maintenance Standards - Control Structure/Flow Restrictor Maintenance Corn- Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed ponent Trash and Debris(Includes Sediment) Material exceeds 25%of sump depth or 1 foot below orifice plate. Control structure orifice is not blocked.All trash and debris removed. Structure is not securely attached to manhole wall. Structure securely attached to wall and outlet pipe. General ° Structure in correct position. Structure is not in upright position(allow up to 10%from plumb). Structural Damage Connections to outlet pipe are water tight; structure repaired or replaced and Connections to outlet pipe are not watertight and show signs of rust. works as designed. Any holes other than designed holes in the structure. Structure has no holes other than designed holes. Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Cleanout Gate Damaged or Missing Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Gate is rusted over 50%of its surface area. Gate is repaired or replaced to meet design standards. Control device is not working properly due to missing, out of place, or Orifice Plate Damaged or Missing bent orifice plate. Plate is in place and works as designed. Obstructions Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions Any trash or debris blocking(or having the potential of blocking)the Pipe is free of all obstructions and works as designed. overflow pipe. Manhole See Table V-A.3: Maintenance Standards-Closed Detention Systems See Table V-A.3: Maintenance Standards-Closed Detention Systems See Table V-A.3: Maintenance Standards-Closed Detention Systems (Tank- (Tanks/Vaults) (Tanks/Vaults) s/Vaults) Catch Basin See Table V-A.5: Maintenance Standards-Catch Basins See Table V-A.5: Maintenance Standards-Catch Basins See Table V-A.5: Maintenance Standards-Catch Basins 2019 Stormwater Management Manual for Western Washington Volume V-Appendix A-Page 1008