2201 EVERETT AVE SEPA 018 - 008 O&M Manual 2025-04-15

OPERATION & MAINTENANCE MANUAL CONVEYANCE SYSTEMS (PIPES, DITCHES & SWALES) Maintenance Defect Conditions When Maintenance is Desired Conditions Component Needed Pipes Sediment&Debris Accumulated sediment that exceeds 20%of Pipe cleaned of all sediment& the pipe. debris. Vegetation Vegetation that reduces free movement of All vegetation removed so water water through pipes. flows freely through pipe. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of the pipe. Any dent that decreases the cross sectional Pipe repaired or replaced. area of the pipe by more than 20%. Open Ditches Trash&Debris Trash&debris exceeds 1 ft3 per 1,000 ft of Trash and debris cleared from ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of Ditch cleaned/flushed of all the design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of Water flow freely through water through ditches. ditches. Erosion Damage to Erosion of the ditch's side slopes and/or Slopes should be stabilized by Slopes scouring of the ditch bottom that exceeds 6", using proper erosion control or where continued erosion is prevalent. measures,and repair methods. Rock Lining out of Place Maintenance person can see native soil Replace rocks to design or Missing(if Applicable) beneath the rock lining. standards. Swales Trash&Debris See above for ditches See above for ditches. Sediment buildup See above for ditches Vegetation may need to be replanted after cleaning. Catch Basins See"Catch Basins"standard. See"Catch Basins"standard. Debris Barriers Sediment&Debris Accumulated sediment/debris that exceeds Debris barrier is free of sediment (e.g.Trash Rack) 20%the inlet opening. &debris. Vegetation Vegetation obstructs more than 20%of the Debris barrier is free of inlet opening. obstructing vegetation. 4