Stormwater Facility Maintenance Manual Public Works Department Surface and Stormwater Management This page intentionally left blank Table of Contents INTRODUCTION ............................................................................................................................ 1 BACKGROUND ............................................................................................................................................................... 1 PURPOSE ...................................................................................................................................................................... 1 OPERATIONS AND MAINTENANCE PROGRAM .............................................................................. 2 MAINTENANCE STANDARDS ............................................................................................................................................. 2 INSPECTION PROGRAM .................................................................................................................................................... 2 OPERATIONS AND MAINTENANCE (O&M) PROGRAM ........................................................................................................... 2 STAFF TRAINING............................................................................................................................................................. 3 STORMWATER STRUCTURES ......................................................................................................... 4 CATCH BASINS ............................................................................................................................................................... 4 Types of Catch Basins: their design & how they function ...................................................................................... 4 Common Maintenance Needs ............................................................................................................................... 5 CATCH BASIN INSERT ..................................................................................................................................................... 11 What is a Catch Basin Insert? .............................................................................................................................. 11 How does a Catch Basin Insert work? .................................................................................................................. 11 Typical Catch Basin Insert designs ...................................................................................................................... 11 YARD DRAIN & CLEANOUT ............................................................................................................................................. 15 What is a Yard Drain? ......................................................................................................................................... 15 How does a Yard Drain work? ............................................................................................................................. 15 Common Maintenance Needs ............................................................................................................................. 15 ENERGY DISSIPATER ...................................................................................................................................................... 19 What is an Energy Dissipater? ............................................................................................................................ 19 Types of Energy Dissipaters ................................................................................................................................. 19 Typical Energy Dissipater Design ........................................................................................................................ 19 Common Maintenance Needs ............................................................................................................................. 19 FLOW CONTROL STRUCTURE .......................................................................................................................................... 27 What is a Flow Control Structure? ...................................................................................................................... 27 Typical Flow Control Structure Design ................................................................................................................ 27 Location of Flow Control Structures .................................................................................................................... 27 Common Maintenance Needs ............................................................................................................................. 27 STORMWATER CONVEYANCE ..................................................................................................... 37 DRAINAGE PIPE ............................................................................................................................................................ 37 What is Drainage Pipe? ....................................................................................................................................... 37 Cleaning Drainage Pipe ....................................................................................................................................... 37 DEBRIS BARRIER (TRASH RACK)....................................................................................................................................... 41 What is a Debris Barrier? .................................................................................................................................... 41 Common Maintenance Needs ............................................................................................................................. 41 STORMWATER FACILITY DISCHARGE POINT (OUTFALL) ......................................................................................................... 47 What is a Stormwater Facility Discharge Point? ................................................................................................. 47 STORMWATER FACILITIES ........................................................................................................... 49 DETENTION POND ........................................................................................................................................................ 49 What is a Detention Pond? ................................................................................................................................. 49 How does a Detention Pond work? ..................................................................................................................... 49 Typical Detention Pond designs .......................................................................................................................... 49 City of Duvall – Stormwater Maintenance Manual Page i Common Maintenance Needs ............................................................................................................................. 49 DETENTION VAULT ........................................................................................................................................................ 56 What is a Detention Vault? ................................................................................................................................. 56 How does a Detention Vault work? ..................................................................................................................... 56 Typical Detention Vault designs .......................................................................................................................... 56 Common Maintenance Needs ............................................................................................................................. 56 DETENTION PIPE .......................................................................................................................................................... 59 What is a Detention Pipe? ................................................................................................................................... 59 How does a Detention Pipe system work? .......................................................................................................... 59 Typical Detention Pipe system designs ............................................................................................................... 59 Common Maintenance Needs ............................................................................................................................. 59 WET POND ................................................................................................................................................................. 68 What is a Wet Pond? ........................................................................................................................................... 68 How does a Wet Pond work? .............................................................................................................................. 68 Typical Wet Pond Design ..................................................................................................................................... 68 Common Maintenance Needs ............................................................................................................................