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2021.0028 MU O&M Manual (Accepted) 10.19.2021 Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Stormwater Operation and Maintenance Plan PREPARED FOR: Mr. Jerry Schuur Schuur Brothers Construction PO Box 597 Puyallup, WA 98371 PROJECT: Tahoma Boulevard Apartments Site Development Yelm, Washington 2210016.10 PREPARED BY: Michael Lesmeister, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager DATE: June 2021 Stormwater Operation and Maintenance Plan PREPARED FOR: Mr. Jerry Schuur Schuur Brothers Construction PO Box 597 Puyallup, WA 98371 PROJECT: Tahoma Boulevard Apartments Site Development Yelm, Washington 2210016.10 PREPARED BY: Michael Lesmeister, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager DATE: June 2021 I hereby state that this Stormwater Operation and Maintenance Plan for the Tahoma Boulevard Apartments project has been prepared by me or under my supervision and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that City of Yelm does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. 06/30/2021 Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 2210016.10 Table of Contents Section Page 1.0 Overall Project Summary .............................................................................................................. 1 2.0 Owner Information ......................................................................................................................... 1 3.0 Description of the Drainage System and Facilities Serving the Site ........................................ 1 4.0 Schedule ......................................................................................................................................... 1 5.0 Cost ................................................................................................................................................. 2 6.0 Site and Facility Management ....................................................................................................... 2 6.1 Pollution Source Control Plan ............................................................................................. 2 6.2 Vegetation Management Plan ............................................................................................. 2 7.0 Instructions for Person Maintaining Stormwater System .......................................................... 2 Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 2210016.10 Appendices Appendix A Exhibits A-1 .................... Vicinity Map A-2 .................... Developed Conditions Map Appendix B Maintenance Checklist Appendix C Source Control BMPs Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 1 2210016.10 1.0 Overall Project Summary This Operations and Maintenance Manual accompanies the civil engineering plans submitted for the Tahoma Boulevard Apartments project. The project is located at 15035 Berry Valley Road SE, Yelm, Washington (Parcel No. 21724420200). The project property is approximately 4.99 acres. Refer to Appendix A-1 for a Vicinity Map. This report presents a maintenance program that meets the requirements of the 201 9 Department of Ecology Stormwater Management Manual for Western Washington (SMMWW), as adopted by City of Yelm. It is vitally important that these facilities be maintained in a timely and conscientious manner to ensure the facilities operate as intended. If the treatment and infiltration facilities are not adequately inspected and maintained periodically, it could lead to local flooding and i ncreased erosion potential. Siltation, debris, or lack of general maintenance can reduce the performance capabilities of the facilities. 2.0 Owner Information All maintenance and operations of onsite stormwater facilities shall be the responsibility of City of Yelm. A brief annual Inspection and Maintenance Report should be conducted by August 31 of each calendar year, include the following: • Name, address, and telephone number of the businesses, persons, or firms responsible for plan implementation, and the person completing the report. • Time period covered by the report, generally the previous calendar year. • A chronological summary of activities conducted to implement the Operation and Maintenance Plan. A photocopy of the log sheet and applicable checklists (with any additional explanation needed) should normally suffice. For any activities conducted by paid parties, include a description of tasks, name of service provider and costs, or include copies of the invoices for services. • An outline of planned activities for the coming year. 3.0 Description of the Drainage System and Facilities Serving the Site The site stormwater system consists of stormwater treatment vaults and an infiltration gallery. Conveyance pipe and catch basins are located through the development. Refer to Appendix A-2 for a Developed Conditions Map. 4.0 Schedule Maintenance of the stormwater facility shall follow the schedule specified in the 201 9 SMMWW maintenance guidelines. Additional maintenance may be required to respond to unusual storm events or reduced performance of the treatment or detention system. A copy of the recommended maintenance schedule is included as Appendix B and may be photocopied and used as inspection records. Inspection reports should be completed annually. Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 2 2210016.10 Routine inspection and maintenance applies to the following systems that are considered an integral part of the onsite stormwater and pollution prevention facilities: • Stormwater Treatment Filters • Infiltration Gallery • Catch Basins • Conveyance Pipe 5.0 Cost The following is an estimate of the average annual cost of maintenance for the stormwater control facilities within the scope of this project: Filter Maintenance @ $175/unit x 7 units $1,225 Personnel @ $25/hour x 80 hours $2,000 Vactor Truck @ $125/hour x 4 hours $500 Dumping Fees @ $45/ton x 10 tons $450 Total Estimated Annual Cost $4,175 6.0 Site and Facility Management 6.1 Pollution Source Control Plan Pollution source control is the application of pollution prevention practices on a developed site to reduce contamination of stormwater runoff at its source. Site specific Best Management Practices (BMPs) have been incorporated into the site plan to reduce the amount of contaminants used or discharged to the environment. Appendix C is a collection of source control BMPs that outline potential pollution point sources and the proposed BMPs used to reduce contamination. 6.2 Vegetation Management Plan The attached maintenance schedule provides guidance on vegetation control and management within the right-of-way. Irrigation and other maintenance, as necessary, shall be provided by the City to ensure that vegetation remains viable and that a hardy root structure forms in the first year. 7.0 Instructions for Person Maintaining Stormwater System Appendix B contains a stormwater facility maintenance schedule. Plan to complete a checklist for all system components per the following schedule: 1. Monthly from November through April; 2. Once in late summer (preferably September); and 3. After any major storm event (items marked “S” only). Using photocopies of the attached pages, check off the problems that are noted each time the item is inspected. Document comments on problems found and the corrective action taken. The Inspection Checklist sheets should be kept on file and used to prepare the annual report. Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 3 2210016.10 This analysis is based on data and records either supplied to or obtained by AHBL. These documents are referenced within the text of the analysis. The analysis has been prepared using procedures and practices within the standard accepted practices of the industry. We conclude that this project, as proposed, will not create any new problems within the existing downstream drainage system. This project will not noticeably aggravate any existing downstream problems due to either water quality or quantity. AHBL, Inc. Michael Lesmeister, EIT Project Engineer ML/lsk June 2021 Q:\2021\2210016\WORDPROC\Reports\20210630 Rpt (O&M) 2210016.10.docx Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 2210016.10 Appendix A Exhibits A-1 .................... Vicinity Map A-2 .................... Developed Conditions Map 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: TAHOMA BLVD APARTMENTS VICINITY MAP A-1 2210016.10 5/19/2021 1ST S T S VICINITY MAP SCALE: 1" = 1/4 MILE (1,320') SITE TAHOMA BLVD SE BERRY VALLEY RD SE E Y E L M A V E C O A T E S A V E NW LONGMIRE ST SECULLENS RD SE93RD AVE SE CRYSTAL SPRINGS ST NWTORNADO ALLEY TAHOMA BOULEVARD SECivil EngineersStructural EngineersLandscape ArchitectsCommunity PlannersLand SurveyorsNeighborsTAHOMA BLVD. APARTMENTS2210016.10NGRAPHIC SCALE0601201" = 60 FEET30BLDG. ABLDG. BBLDG. CBLDG. DROAD ATAHOMA BLVD NESITE DATASITE AREA: 4.99 ACSITE COVER:ROOF: 0.79 ACSIDEWALK:0.26 ACPAVEMENT: 1.89 ACLANDSCAPE:2.05 ACRUN-ON BASIN:PASTURE:1.20 ACPARCEL #: 21724420200ADDRESS: 15035 BERRY VALLEY RD SEONSITE BASINRUN-ON BASININFILTRATION GALLERY2,500 SF FOOTPRINT(125' X 20' X 4')12" PVC PERF10' O.C.12" PVC MANIFOLD STORMFILTERVAULTMAINTENANCEACCESSMANHOLE Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 2210016.10 Appendix B Maintenance Checklist PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL A-6 Volume I – Minimum Technical Requirements and Site Planning December 2015 #2 – Maintenance Checklist for Infiltration Basins and Trenches: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Trash and Debris Any trash and debris which exceed five cubic feet per 1,000 square feet. If less than threshold, all trash and debris will be removed as part of next scheduled maintenance. Trash and debris cleared from site. General Poisonous Vegetation and Noxious W eeds Any poisonous or nuisance vegetation which may constitute a hazard to maintenance personnel or the public. Any evidence of noxious weeds as defined in the Pierce County Noxious Weeds List. (Apply requirements of adopted integrated pest management policies for the use of herbicides.) No danger of poisonous vegetation where maintenance personnel or the public might normally be. (Coordinate with Tacoma-Pierce County Health Department) Complete eradication of noxious weeds may not be possible. Compliance with state or local eradication policies required. General Contaminants and Pollution Any evidence of oil, gasoline, contaminants or other pollutants. No contaminants or pollutants present. (Coordinate removal/cleanup with Pierce County Surface Water Management 253-798-2725 and/or Dept. of Ecology Spill Response 800- 424-8802.) General Rodent Holes If the facility is constructed with a dam or berm, look for rodent holes or any evidence of water piping through the dam or berm. Rodents removed and dam or berm repaired. (Coordinate with Tacoma- Pierce County Health Department; coordinate with Ecology Dam Safety Office if pond exceeds 10 acre-feet.) General Beaver Dams Beaver dam results in an adverse change in the functioning of the facility. Facility returned to design function. (Contact WDFW Region 6 to identify the appropriate Nuisance Wildlife Control Operator) General Insects When insects such as wasps and hornets interfere with maintenance activities. Insects destroyed or removed from site. Apply insecticides in compliance with adopted integrated pest management policies. General Performance Check crest gauge against design expectations (see Maintenance and Source Control Manual). Crest gauge results reflect design performance expectations. Reading recorded. County notified if not meeting design performance. Crest Gauge Crest Gauge Missing/ Broken Crest gauge is not functioning properly, has been vandalized, or is missing. Crest gauge present and functioning. Repair/replace crest gauge if missing or broken. Storage Area Water Not Infiltrating Water ponding in infiltration basin after rainfall ceases and appropriate time allowed for infiltration. Treatment basins should infiltrate Water Quality Design Storm Volume within 48 hours, and empty within 24 hours after cessation of most rain events. (A percolation test pit or test of facility indicates facility is only working at 90 percent of its designed capabilities. If 2 inches or more sediment is present, remove). Facility infiltrates as designed. Sediment is removed and/or facility is cleaned so that infiltration system works according to design. PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL December 2015 Volume I – Minimum Technical Requirements and Site Planning A-7 #2 – Maintenance Checklist for Infiltration Basins and Trenches: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Filter Bags (if applicable) Filled with Sediment and Debris Sediment and debris fill bag more than one-half full. Filter bag less than one-half full. Filter bag is replaced or system is redesigned. Rock Filters Sediment and Debris By visual inspection, little or no water flows through filter during heavy rain storms. Water flows through filter. Replace gravel in rock filter if needed. Trenches Observation Well (Use Surface of Trench if W ell is Not Present) Water ponds at surface during storm events. Less than 90 percent of design infiltration rate. Remove and replace/clean rock and geomembrane. Ponds Vegetation Exceeds 18 inches. Grass or groundcover mowed to a height no greater than 6 inches. Ponds Vegetation Bare spots. No bare spots. Revegetate and stabilize immediately. Side Slopes of Pond Erosion Erosion damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Slopes stabilized using appropriate erosion control measure(s); e.g., rock reinforcement, planting of grass, compaction. If erosion is occurring on compacted slope, a professional engineer should be consulted to resolve source of erosion. Pond Berms (Dikes) Settlements Any part of berm which has settled 4 inches lower than the design elevation. If settlement is apparent, measure berm to determine amount of settlement. Settling can be an indication of more severe problems with the berm or outlet works. Dike is built back to the design elevation. If settlement is significant, a professional engineer should be consulted to determine the cause of the settlement. Pond Berms (Dikes) Piping Discernable water flow through pond berm. Ongoing erosion with potential for erosion to continue. No water flow through pond berm. Piping eliminated. Erosion potential eliminated. Recommend a geotechnical engineer be called in to inspect and evaluate condition and recommend repair of condition. General Hazard Trees If dead, diseased, or dying trees are identified. Hazard trees removed. (Use a certified Arborist to determine health of tree or removal requirements). General Tree Growth and Dense Vegetation Tree growth and dense vegetation which impedes inspection, maintenance access or interferes with maintenance activity (i.e., slope mowing, silt removal, vactoring, or equipment movements). Trees and vegetation do not hinder inspection or maintenance activities. Harvested trees should be recycled into mulch or other beneficial uses (e.g., alders for firewood). PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL A-8 Volume I – Minimum Technical Requirements and Site Planning December 2015 #2 – Maintenance Checklist for Infiltration Basins and Trenches: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Pond Berms (Dikes) Tree Growth Tree growth on berms over 4 feet in height may lead to piping through the berm which could lead to failure of the berm. Trees on berms removed. If root system is small (base less than 4 inches) the root system may be left in place. Otherwise the roots should be removed and the berm restored. A professional engineer should be consulted for proper berm/spillway restoration. Emergency Overflow/ Spillway Tree Growth Tree growth on emergency spillways creates blockage problems and may cause failure of the berm due to uncontrolled overtopping. Trees on emergency spillways removed. If root system is small (base less than 4 inches) the root system may be left in place. Otherwise the roots should be removed and the berm restored. A professional engineer should be consulted for proper berm/spillway restoration. Emergency Overflow/ Spillway Rock Missing Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rocks and pad depth restored to design standards. (Riprap on inside slopes need not be replaced.) Emergency Overflow/ Spillway Erosion Erosion damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted berm embankment. Slopes stabilized using appropriate erosion control measure(s); e.g., rock reinforcement, planting of grass, compaction. If erosion is occurring on compacted berms a professional engineer should be consulted to resolve source of erosion. Presettling Ponds and Vaults Facility or sump filled with Sediment and/or Debris 6 inches or designed sediment trap depth of sediment. No sediment present in presettling pond or vault. Sediment is removed. Drain Rock Water Ponding If water enters the facility from the surface, inspect to see if water is ponding at the surface during storm events. If buried drain rock, observe drawdown through observation port or cleanout. No water ponding on surface during storm events. Clear piping through facility when ponding occurs. Replace rock material/sand reservoirs as necessary. Tilling of subgrade below reservoir may be necessary (for trenches) prior to backfill. If you are unsure whether a problem exists, contact a professional engineer. Volume V – Runoff Treatment BMPs – December 2014 4-38 No. 5 – Catch Basins Maintenance Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is performed General Trash & Debris Trash or debris which is located immediately in front of the catch basin opening or is blocking inletting capacity of the basin by more than 10%. No Trash or debris located immediately in front of catch basin or on grate opening. Trash or debris (in the basin) that exceeds 60 percent of the sump depth as measured from the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. No trash or debris in the catch basin. Trash or debris in any inlet or outlet pipe blocking more than 1/3 of its height. Inlet and outlet pipes free of trash or debris. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within the catch basin. Sediment Sediment (in the basin) that exceeds 60 percent of the sump depth as measured from the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. No sediment in the catch basin Structure Damage to Frame and/or Top Slab Top slab has holes larger than 2 square inches or cracks wider than 1/4 inch (Intent is to make sure no material is running into basin). Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than 3/4 inch of the frame from the top slab. Frame not securely attached Frame is sitting flush on the riser rings or top slab and firmly attached. Fractures or Cracks in Basin Walls/ Bottom Maintenance person judges that structure is unsound. Basin replaced or repaired to design standards. Grout fillet has separated or cracked wider than 1/2 inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. Pipe is regrouted and secure at basin wall. Settlement/ Misalignment If failure of basin has created a safety, function, or design problem. Basin replaced or repaired to design standards. Vegetation Vegetation growing across and blocking more than 10% of the basin opening. No vegetation blocking opening to basin. Vegetation growing in inlet/outlet pipe joints that is more than six inches tall and less than six inches apart. No vegetation or root growth present. Contamination and Pollution See "Detention Ponds" (No. 1). No pollution present. Volume V – Runoff Treatment BMPs – December 2014 4-39 No. 5 – Catch Basins Maintenance Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is performed Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Any open catch basin requires maintenance. Catch basin cover is closed Locking Mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts into frame have less than 1/2 inch of thread. Mechanism opens with proper tools. Cover Difficult to Remove One maintenance person cannot remove lid after applying normal lifting pressure. (Intent is keep cover from sealing off access to maintenance.) Cover can be removed by one maintenance person. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, not securely attached to basin wall, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. Metal Grates (If Applicable) Grate opening Unsafe Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and Debris Trash and debris that is blocking more than 20% of grate surface inletting capacity. Grate free of trash and debris. Damaged or Missing. Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. No. 6 – Debris Barriers (e.g., Trash Racks) Maintenance Components Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed General Trash and Debris Trash or debris that is plugging more than 20% of the openings in the barrier. Barrier cleared to design flow capacity. Metal Damaged/ Missing Bars. Bars are bent out of shape more than 3 inches. Bars in place with no bends more than 3/4 inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50% deterioration to any part of barrier. Barrier replaced or repaired to design standards. Inlet/Outlet Pipe Debris barrier missing or not attached to pipe Barrier firmly attached to pipe PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL December 2015 Volume I – Minimum Technical Requirements and Site Planning A-25 #15 – Maintenance Checklist for Manufactured Media Filters. Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Media filter vault Sediment Accumulation on Top of Filter Cartridges Sediment accumulation exceeds 0.25 inches on top of cartridges. No sediment deposits on top of cartridges. Sediment on cartridges likely indicates that cartridges are plugged and require maintenance. Media filter vault Sediment Accumulation in Vault Sediment accumulation in vault exceeds 6 inches. Look for other indicators of clogged cartridges or overflow. No sediment accumulation in vault. Sediment in vault should be removed. Cartridges should be checked and replaced or serviced as needed. Media filter vault Trash and Floatable Debris Accumulation Trash and floatable debris accumulation in vault. No trash or other floatable debris in filter vault. Media filter vault Filter Cartridges Submerged Filter vault does not drain within 24 hours following storm. Look for evidence of submergence due to backwater or excessive hydrocarbon loading. Filter media checked and replaced if needed. If cartridges are plugged with oil additional treatment or source control BMP may be needed. Forebay Sediment Accumulation Sediment accumulation exceeds 6 inches or one-third of the available sump. Sediment accumulation less than 6 inches. Forebay Trash and Floatable Debris Accumulation Trash and/or floatable debris accumulation. No trash or other floatable debris accumulation in forebay. Trash and/or floatable debris should be removed during inspections. Significant oil accumulation may indicate the need for additional treatment or source control. Drain Pipes/ Cleanouts Sediment in Drain Pipes/Cleanouts Accumulated sediment that exceeds 20 percent of the diameter. No sediment or debris in drainpipes or cleanouts. Sediment and debris removed. Below ground vault Access cover Damaged/ Not working One maintenance person cannot remove lid after applying 80 pounds of lift, corrosion of deformation of cover. Cover repaired to proper working specifications or replaced. Below ground vault Damaged Pipes Any part of the pipes are crushed or damaged due to corrosion and/or settlement. Pipe repaired or replaced. Below ground vault Vault Structure Has Cracks in Wall, Bottom, and Damage to Frame and/or Top Slab. Cracks wider than one-half inch or evidence of soil particles entering the structure through the cracks, or maintenance/inspection personnel determine that the vault is not structurally sound. Vault repaired or replaced so that vaults meets design specifications and is structurally sound. Below ground vault Vault Structure has Cracks in Wall, Bottom, and Damage to Frame and/or Top Slab. Cracks wider than 0.5 inch at the joint of any inlet/outlet pipe or evidence of soil particles entering through the cracks. Vault repaired so that no cracks exist wider than 0.25 inch at the joint of inlet/outlet pipe. Below ground vault Baffles Baffles corroding, cracking, warping, and/or showing signs of failure as determined by maintenance/inspection person. Baffles repaired or replaced to design specifications. PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL A-26 Volume I – Minimum Technical Requirements and Site Planning December 2015 #15 – Maintenance Checklist for Manufactured Media Filters. Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Below ground vault Ladder Rungs Unsafe Maintenance person judges that ladder is unsafe due to missing rungs, misalignment, rust, or cracks. Ladder must be fixed or secured immediately. Ladder meets design standards and allows maintenance persons safe access. Below Ground Cartridge Type Media Drawdown of water through the media takes longer than 1 hour, and/or overflow occurs frequently. Media cartridges replaced. Below Ground Cartridge Type Short Circuiting Flows do not properly enter filter cartridges. Filter cartridges replaced. Also check Department of Ecology website and manufacturer guidelines for updates to O&M requirements. If you are unsure whether a problem exists, contact a professional engineer. A vault is a confined space. Visual inspections should be performed aboveground. If entry is required, it should be performed by qualified personnel. PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL December 2015 Volume I – Minimum Technical Requirements and Site Planning A-33 #20 – Maintenance Checklist for Grounds (Landscaping): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Weeds (nonpoisonous) Weeds growing in more than 20 percent of the landscaped area (trees and shrubs only). See also Pierce County Noxious weeds list at: piercecountyweedboard.wsu.edu/weedli st.html Weeds present in less than five percent of the landscaped area. General Insect Hazard Any presence of poison ivy or other poisonous vegetation or insect nests. No poisonous vegetation or insect nests present in landscaped area. General Trash or Litter See Detention Ponds (Checklist #1). See Detention Ponds (Checklist #1). General Erosion of Ground Surface Noticeable rills are seen in landscaped areas. Causes of erosion are identified and steps taken to slow down/spread out the water. Eroded areas are filled, contoured, and seeded. Trees and shrubs Damage Limbs or parts of trees or shrubs that are split or broken which affect more than 25 percent of the total foliage of the tree or shrub. Trim trees/shrubs to restore shape. Replace trees/shrubs with severe damage. Trees and shrubs Damage Trees or shrubs that have been blown down or knocked over. Tree replanted, inspected for injury to stem or roots. Replace if severely damaged. Trees and shrubs Damage Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Stakes and rubber-coated ties placed around young trees/shrubs for support. StormFilter Inspection and Maintenance Procedures ENGINEERED SOLUTIONS In addition to these two activities, it is important to check the condition of the StormFilter unit after major storms for potential damage caused by high flows and for high sediment accumulation that may be caused by localized erosion in the drainage area. It may be necessary to adjust the inspection/ maintenance schedule depending on the actual operating conditions encountered by the system. In general, inspection activities can be conducted at any time, and maintenance should occur, if warranted, during dryer months in late summer to early fall. Maintenance Frequency The primary factor for determining frequency of maintenance for the StormFilter is sediment loading. A properly functioning system will remove solids from water by trapping particulates in the porous structure of the filter media inside the cartridges. The flow through the system will naturally decrease as more and more particulates are trapped. Eventually the flow through the cartridges will be low enough to require replacement. It may be possible to extend the usable span of the cartridges by removing sediment from upstream trapping devices on a routine as-needed basis, in order to prevent material from being re-suspended and discharged to the StormFilter treatment system. The average maintenance lifecycle is approximately 1-5 years. Site conditions greatly influence maintenance requirements. StormFilter units located in areas with erosion or active construction may need to be inspected and maintained more often than those with fully stabilized surface conditions. Regulatory requirements or a chemical spill can shift maintenance timing as well. The maintenance frequency may be adjusted as additional monitoring information becomes available during the inspection program. Areas that develop known problems should be inspected more frequently than areas that demonstrate no problems, particularly after major storms. Ultimately, inspection and maintenance activities should be scheduled based on the historic records and characteristics of an individual StormFilter system or site. It is recommended that the site owner develop a database to properly manage StormFilter inspection and maintenance programs.. 2 3 Maintenance Guidelines The primary purpose of the Stormwater Management StormFilter® is to filter and prevent pollutants from entering our waterways. Like any effective filtration system, periodically these pollutants must be removed to restore the StormFilter to its full efficiency and effectiveness. Maintenance requirements and frequency are dependent on the pollutant load characteristics of each site. Maintenance activities may be required in the event of a chemical spill or due to excessive sediment loading from site erosion or extreme storms. It is a good practice to inspect the system after major storm events. Maintenance Procedures Although there are many effective maintenance options, we believe the following procedure to be efficient, using common equipment and existing maintenance protocols. The following two-step procedure is recommended:: 1. Inspection • Inspection of the vault interior to determine the need for maintenance. 2. Maintenance • Cartridge replacement • Sediment removal Inspection and Maintenance Timing At least one scheduled inspection should take place per year with maintenance following as warranted. First, an inspection should be done before the winter season. During the inspection the need for maintenance should be determined and, if disposal during maintenance will be required, samples of the accumulated sediments and media should be obtained. Second, if warranted, a maintenance (replacement of the filter cartridges and removal of accumulated sediments) should be performed during periods of dry weather. 2 3 Inspection Procedures The primary goal of an inspection is to assess the condition of the cartridges relative to the level of visual sediment loading as it relates to decreased treatment capacity. It may be desirable to conduct this inspection during a storm to observe the relative flow through the filter cartridges. If the submerged cartridges are severely plugged, then typically large amounts of sediments will be present and very little flow will be discharged from the drainage pipes. If this is the case, then maintenance is warranted and the cartridges need to be replaced. Warning: In the case of a spill, the worker should abort inspection activities until the proper guidance is obtained. Notify the local hazard control agency and Contech Engineered Solutions immediately. To conduct an inspection: Important: Inspection should be performed by a person who is familiar with the operation and configuration of the StormFilter treatment unit. 1. If applicable, set up safety equipment to protect and notify surrounding vehicle and pedestrian traffic. 2. Visually inspect the external condition of the unit and take notes concerning defects/problems. 3. Open the access portals to the vault and allow the system vent. 4. Without entering the vault, visually inspect the inside of the unit, and note accumulations of liquids and solids. 5. Be sure to record the level of sediment build-up on the floor of the vault, in the forebay, and on top of the cartridges. If flow is occurring, note the flow of water per drainage pipe. Record all observations. Digital pictures are valuable for historical documentation. 6. Close and fasten the access portals. 7. Remove safety equipment. 8. If appropriate, make notes about the local drainage area relative to ongoing construction, erosion problems, or high loading of other materials to the system. 9. Discuss conditions that suggest maintenance and make decision as to weather or not maintenance is needed. Maintenance Decision Tree The need for maintenance is typically based on results of the inspection. The following Maintenance Decision Tree should be used as a general guide. (Other factors, such as Regulatory Requirements, may need to be considered) 1. Sediment loading on the vault floor. a. If >4” of accumulated sediment, maintenance is required. 2. Sediment loading on top of the cartridge. a. If >1/4” of accumulation, maintenance is required. 3. Submerged cartridges. a. If >4” of static water above cartridge bottom for more than 24 hours after end of rain event, maintenance is required. (Catch basins have standing water in the cartridge bay.) 4. Plugged media. a. If pore space between media granules is absent, maintenance is required. 5. Bypass condition. a. If inspection is conducted during an average rain fall event and StormFilter remains in bypass condition (water over the internal outlet baffle wall or submerged cartridges), maintenance is required. 6. Hazardous material release. a. If hazardous material release (automotive fluids or other) is reported, maintenance is required. 7. Pronounced scum line. a. If pronounced scum line (say ≥ 1/4” thick) is present above top cap, maintenance is required. Important: Care must be used to avoid damaging the cartridges during removal and installation. The cost of repairing components damaged during maintenance will be the responsibility of the owner. C. Set the used cartridge aside or load onto the hauling truck. D. Continue steps a through c until all cartridges have been removed. Method 2: A. This activity will require that maintenance personnel enter the vault to remove the cartridges from the under drain manifold and place them under the vault opening for lifting (removal). Disconnect each filter cartridge from the underdrain connector by rotating counterclockwise 1/4 of a turn. Roll the loose cartridge, on edge, to a convenient spot beneath the vault access. B. Unscrew the cartridge cap. C. Remove the cartridge hood and float. D. At location under structure access, tip the cartridge on its side. E. Empty the cartridge onto the vault floor. Reassemble the empty cartridge. F. Set the empty, used cartridge aside or load onto the hauling truck. G. Continue steps a through e until all cartridges have been removed. 4 5 Maintenance Depending on the configuration of the particular system, maintenance personnel will be required to enter the vault to perform the maintenance. Important: If vault entry is required, OSHA rules for confined space entry must be followed. Filter cartridge replacement should occur during dry weather. It may be necessary to plug the filter inlet pipe if base flows is occurring. Replacement cartridges can be delivered to the site or customers facility. Information concerning how to obtain the replacement cartridges is available from Contech Engineered Solutions. Warning: In the case of a spill, the maintenance personnel should abort maintenance activities until the proper guidance is obtained. Notify the local hazard control agency and Contech Engineered Solutions immediately. To conduct cartridge replacement and sediment removal maintenance: 1. If applicable, set up safety equipment to protect maintenance personnel and pedestrians from site hazards. 2. Visually inspect the external condition of the unit and take notes concerning defects/problems. 3. Open the doors (access portals) to the vault and allow the system to vent. 4. Without entering the vault, give the inside of the unit, including components, a general condition inspection. 5. Make notes about the external and internal condition of the vault. Give particular attention to recording the level of sediment build-up on the floor of the vault, in the forebay, and on top of the internal components. 6. Using appropriate equipment offload the replacement cartridges (up to 150 lbs. each) and set aside. 7. Remove used cartridges from the vault using one of the following methods: Method 1: A. This activity will require that maintenance personnel enter the vault to remove the cartridges from the under drain manifold and place them under the vault opening for lifting (removal). Disconnect each filter cartridge from the underdrain connector by rotating counterclockwise 1/4 of a turn. Roll the loose cartridge, on edge, to a convenient spot beneath the vault access. Using appropriate hoisting equipment, attach a cable from the boom, crane, or tripod to the loose cartridge. Contact Contech Engineered Solutions for suggested attachment devices. B. Remove the used cartridges (up to 250 lbs. each) from the vault. 4 5 8. Remove accumulated sediment from the floor of the vault and from the forebay. This can most effectively be accomplished by use of a vacuum truck. 9. Once the sediments are removed, assess the condition of the vault and the condition of the connectors. 10. Using the vacuum truck boom, crane, or tripod, lower and install the new cartridges. Once again, take care not to damage connections. 11. Close and fasten the door. 12. Remove safety equipment. 13. Finally, dispose of the accumulated materials in accordance with applicable regulations. Make arrangements to return the used empty cartridges to Contech Engineered Solutions. Related Maintenance Activities - Performed on an as-needed basis StormFilter units are often just one of many structures in a more comprehensive stormwater drainage and treatment system. In order for maintenance of the StormFilter to be successful, it is imperative that all other components be properly maintained. The maintenance/repair of upstream facilities should be carried out prior to StormFilter maintenance activities. In addition to considering upstream facilities, it is also important to correct any problems identified in the drainage area. Drainage area concerns may include: erosion problems, heavy oil loading, and discharges of inappropriate materials. Material Disposal The accumulated sediment found in stormwater treatment and conveyance systems must be handled and disposed of in accordance with regulatory protocols. It is possible for sediments to contain measurable concentrations of heavy metals and organic chemicals (such as pesticides and petroleum products). Areas with the greatest potential for high pollutant loading include industrial areas and heavily traveled roads. Sediments and water must be disposed of in accordance with all applicable waste disposal regulations. When scheduling maintenance, consideration must be made for the disposal of solid and liquid wastes. This typically requires coordination with a local landfill for solid waste disposal. For liquid waste disposal a number of options are available including a municipal vacuum truck decant facility, local waste water treatment plant or on-site treatment and discharge. Inspection Report Date: Personnel: Location: ————————————System Size: ——————————————————————————————————— System Type: Vault Cast-In-Place Linear Catch Basin Manhole Other Sediment Thickness in Forebay: ——————————————————————————————————————————— Sediment Depth on Vault Floor: ——————————————————————————————————————————— Structural Damage: ———————————————————————————————————————————————— Estimated Flow from Drainage Pipes (if available): ———————————————————————————————————— Cartridges Submerged: Yes No Depth of Standing Water: —————————————————————— StormFilter Maintenance Activities (check off if done and give description) Trash and Debris Removal: ——————————————————————————————————————————— Minor Structural Repairs: ———————————————————————————————————————————— Drainage Area Report ————————————————————————————————————————————— Excessive Oil Loading: Yes No Source: ——————————————————————— Sediment Accumulation on Pavement: Yes No Source: ——————————————————————— Erosion of Landscaped Areas: Yes No Source: ——————————————————————— Items Needing Further Work: ———————————————————————————————————————————— Owners should contact the local public works department and inquire about how the department disposes of their street waste residuals. Other Comments: ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— Review the condition reports from the previous inspection visits. Date: StormFilter Maintenance Report Date: —————————————Personnel: ———————————————————————————————————— Location: ————————————System Size: ——————————————————————————————————— System Type: Vault Cast-In-Place Linear Catch Basin Manhole Other List Safety Procedures and Equipment Used: —————————————————————————————————————— ————————————————————————————————————————————————————————— ————————————————————————————————————————————————————————— System Observations Months in Service: Oil in Forebay (if present): Yes No Sediment Depth in Forebay (if present): ———————————————————————————————————————— Sediment Depth on Vault Floor: ——————————————————————————————————————————— Structural Damage: ———————————————————————————————————————————————— Drainage Area Report Excessive Oil Loading: Yes No Source: ————————————————————————— Sediment Accumulation on Pavement: Yes No Source: ————————————————————————— Erosion of Landscaped Areas: Yes No Source: ————————————————————————— StormFilter Cartridge Replacement Maintenance Activities Remove Trash and Debris: Yes No Details: —————————————————————————— Replace Cartridges: Yes No Details: —————————————————————————— Sediment Removed: Yes No Details: —————————————————————————— Quantity of Sediment Removed (estimate?): Minor Structural Repairs: Yes No Details: ————————————————————————— Residuals (debris, sediment) Disposal Methods: —————————————————————————————————————— Notes: —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— 800.338.1122 www.conteches.com NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANT Y OR AN IMPLIED WARRANT Y OF MERCHANTABILITY OR FITNESS FOR AN Y PARTICULAR PURPOSE . SEE THE CONTECH STANDARD CONDITIONS OF SALE (VIEWABLE AT WWW.CONTECHES.COM /COS ) FOR MORE INFORMATION . Contech Engineered Solutions LLC provides site solutions for the civil engineering industry. Contech’s portfolio includes bridges, drainage, sanitary sewer, stormwater and earth stabilization products. For information on other Contech division offerings, visit contech-cpi.com or call 800.338.1122. Support • Drawings and specifications are available at www.conteches.com. • Site-specific design support is available from our engineers. ENGINEERED SOLUTIONS ©2016 CONTECH ENGINEERED SOLUTIONS LLC. 800-338-1122 www.ContechES.com All Rights Reserved. Printed in the USA. StormFilter Inspection and Maintenance Procedures 8/2016 PIERCE COUNTY STORMWATER and SITE DEVELOPMENT MANUAL December 2015 Volume I – Minimum Technical Requirements and Site Planning A-35 #22 – Maintenance Checklist for Conveyance Systems (Pipes and Ditches): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Pipes Sediment & Debris Accumulated sediment that exceeds 20 percent of the diameter of the pipe. Pipe cleaned of all sediment and debris. Pipes Vegetation Vegetation that reduces free movement of water though pipes. Vegetation does not impeded free movement of water through pipes. Prohibit use of sand and sealant application and protect from construction runoff. Pipes Damaged (Rusted, Bent or Crushed) Protective coating is damaged: rust is causing more than 50 percent deterioration to any part of pipe. Pipe repaired or replaced. Pipes Damaged (Rusted, Bent or Crushed) Any dent that significantly impedes flow (i.e. decreases the cross section area of pipe by more than 20 percent). Pipe repaired or replaced. Pipes Damaged (Rusted, Bent or Crushed) Pipe has major cracks or tears allowing groundwater leakage. Pipe repaired or replaced. Open Ditches Trash & Debris Dumping of yard wastes such as grass clippings and branches. Unsightly accumulation of non-degradable materials such as glass, plastic, metal, foam, and coated paper. No trash or debris present. Trash and debris removed and disposed of as prescribed by the County. Open Ditches Sediment Buildup Accumulated sediment that exceeds 20 percent of the design depth. Ditch cleaned of all sediment and debris so that it matches design. Open Ditches Vegetation Vegetation (e.g. weedy shrubs or saplings) that reduces free movements of water through ditches. Water flows freely though ditches. Grassy vegetation should be left alone. Open Ditches Erosion Damage to Slopes Erosion damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. No erosion damage present. Slopes stabilized using appropriate erosion control measure(s); e.g., rock reinforcement, planting of grass, compaction. Open Ditches Erosion Damage to Slopes Any erosion observed on a compacted berm embankment. If erosion is occurring on compacted berms a professional engineer should be consulted to resolve source of erosion. Open Ditches Rock Lining Out of Place or Missing (If Applicable) Native soil is exposed beneath the rock lining. Rocks replaced to design standards. If you are unsure whether a problem exists, contact a professional engineer. Stormwater Operation and Maintenance Plan Tahoma Boulevard Apartments Site Development 2210016.10 Appendix C Source Control BMPs Volume IV - Source Control BMPs – December 2014 2-20 of the mixture. Stormwater could be conveyed to a sanitary sewer system if it is determined not to be explosive. • Transfer the fuel from the delivery tank trucks to the fuel storage tank in impervious contained areas and ensure that appropriate overflow protection is used. Alternatively, cover nearby storm drains during the filling process and use drip pans under all hose connections. Additional BMP for Vehicles 10 feet in height or greater A roof or canopy may not be feasible at fueling stations that regularly fuel vehicles that are 10 feet in height or greater, particularly at industrial or WSDOT sites. At those types of fueling facilities, the following BMPs apply, as well as the applicable BMPs and fire prevention (UFC requirements) of this BMP for fueling stations: • If a roof or canopy is impractical, the concrete fueling pad must be equipped with emergency spill control including a shutoff valve for drainage from the fueling area. Maintain the valve in the closed position in the event of a spill. An electronically actuated valve is preferred to minimize the time lapse between spill and containment. Clean up spills and dispose of materials off-site in accordance with S406 BMPs for Spills of Oil and Hazardous Substances. • The valve may be opened to convey contaminated stormwater to a sanitary sewer, if approved by the sewer authority, or to oil removal treatment such as an API or CP oil/water separator, catchbasin insert, or equivalent treatment, and then to a basic treatment BMP. Discharges from treatment systems to storm sewer or surface water or to the ground must not display ongoing or recurring visible sheen and must not contain greater than a significant amount of oil and grease. S410 BMPs for Illicit Connections to Storm Drains Description of Pollutant Sources: Illicit connections are unpermitted sanitary or process wastewater discharges to a storm sewer or to surface water, rather than to a sanitary sewer, industrial process wastewater, or other appropriate treatment. They can also include swimming pool water, filter backwash, cleaning solutions/washwaters, cooling water, etc. Experience has shown that illicit connections are common, particularly in older buildings. Pollutant Control Approach: Identify and eliminate unpermitted discharges or obtain an NPDES permit, where necessary, particularly at industrial and commercial facilities. Volume IV - Source Control BMPs – December 2014 2-21 Applicable Operational BMPs: • Eliminate unpermitted wastewater discharges to storm sewer, ground water, or surface water. • Convey unpermitted discharges to a sanitary sewer if allowed by the local sewer authority, or to other approved treatment. • Obtain appropriate state and local permits for these discharges. Recommended Additional Operational BMPs: At commercial and industrial facilities, conduct a survey of wastewater discharge connections to storm drains and to surface water as follows: • Conduct a field survey of buildings, particularly older buildings, and other industrial areas to locate storm drains from buildings and paved surfaces. Note where these join the public storm drain(s). • During non-stormwater conditions inspect each storm drain for non- stormwater discharges. Record the locations of all non-stormwater discharges. Include all permitted discharges. • If useful, prepare a map of each area. Show on the map the known location of storm sewers, sanitary sewers, and permitted and unpermitted discharges. Aerial photos may be useful. Check records such as piping schematics to identify known side sewer connections and show these on the map. Consider using smoke, dye, or chemical analysis tests to detect connections between two conveyance systems (e.g., process water and stormwater). If desirable, conduct TV inspections of the storm drains and record the footage on videotape. • Compare the observed locations of connections with the information on the map and revise the map accordingly. Note suspect connections that are inconsistent with the field survey. • Identify all connections to storm sewers or to surface water and take the actions specified above as applicable BMPs. S411 BMPs for Landscaping and Lawn/ Vegetation Management Description of Pollutant Sources: Landscaping can include grading, soil transfer, vegetation removal, pesticide and fertilizer applications, and watering. Stormwater contaminants include toxic organic compounds, heavy metals, oils, total suspended solids, coliform bacteria, fertilizers, and pesticides. Lawn and vegetation management can include control of objectionable weeds, insects, mold, bacteria, and other pests with pesticides. Examples include weed control on golf course lawns, access roads, and utility corridors and during landscaping; sap stain and insect control on lumber and logs; rooftop moss removal; killing nuisance rodents; fungicide application to patio decks, and residential lawn/plant care. It is possible to Volume IV - Source Control BMPs – December 2014 2-22 release toxic pesticides such as pentachlorophenol, carbamates, and organometallics to the environment by leaching and dripping from treated parts, container leaks, product misuse, and outside storage of pesticide contaminated materials and equipment. Poor management of the vegetation and poor application of pesticides or fertilizers can cause appreciable stormwater contamination. Pollutant Control Approach: Control of fertilizer and pesticide applications, soil erosion, and site debris to prevent contamination of stormwater. Develop and implement an Integrated Pest Management Plan (IPM) and use pesticides only as a last resort. Carefully apply pesticides/ herbicides, in accordance with label instructions. Maintain appropriate vegetation, with proper fertilizer application where practicable, to control erosion and the discharge of stormwater pollutants. Where practicable grow plant species appropriate for the site, or adjust the soil properties of the subject site to grow desired plant species. Applicable Operational BMPs for Landscaping: • Install engineered soil/landscape systems to improve the infiltration and regulation of stormwater in landscaped areas. • Do not dispose of collected vegetation into waterways or storm sewer systems. Recommended Additional Operational BMPs for Landscaping: • Conduct mulch-mowing whenever practicable • Dispose of grass clippings, leaves, sticks, or other collected vegetation, by composting, if feasible. • Use mulch or other erosion control measures on soils exposed for more than one week during the dry season or two days during the rainy season. • Store and maintain appropriate oil and chemical spill cleanup materials in readily accessible locations when using oil or other chemicals. Ensure that employees are familiar with proper spill cleanup procedures. • Till fertilizers into the soil rather than dumping or broadcasting onto the surface. Determine the proper fertilizer application rate for the types of soil and vegetation encountered. • Till a topsoil mix or composted organic material into the soil to create a well-mixed transition layer that encourages deeper root systems and drought-resistant plants. • Use manual and/or mechanical methods of vegetation removal rather than applying herbicides, where practical. Volume IV - Source Control BMPs – December 2014 2-23 Applicable Operational BMPs for the Use of Pesticides: • Develop and implement an IPM (See section on IPM in Applicable Operational BMPs for Vegetation Management) and use pesticides only as a last resort. • Implement a pesticide-use plan and include at a minimum: a list of selected pesticides and their specific uses; brands, formulations, application methods and quantities to be used; equipment use and maintenance procedures; safety, storage, and disposal methods; and monitoring, record keeping, and public notice procedures. All procedures shall conform to the requirements of Chapter 17.21 RCW and Chapter 16-228 WAC (Appendix IV-D R.7). • Choose the least toxic pesticide available that is capable of reducing the infestation to acceptable levels. The pesticide should readily degrade in the environment and/or have properties that strongly bind it to the soil. Conduct any pest control activity at the life stage when the pest is most vulnerable. For example, if it is necessary to use a Bacillus thuringiens application to control tent caterpillars, apply it to the material before the caterpillars cocoon or it will be ineffective. Any method used should be site-specific and not used wholesale over a wide area. • Apply the pesticide according to label directions. Do not apply pesticides in quantities that exceed manufacturer’s instructions. • Mix the pesticides and clean the application equipment in an area where accidental spills will not enter surface or ground waters, and will not contaminate the soil. • Store pesticides in enclosed areas or in covered impervious containment. Do not discharge pesticide contaminated stormwater or spills/leaks of pesticides to storm sewers. Do not hose down the paved areas to a storm sewer or conveyance ditch. Store and maintain appropriate spill cleanup materials in a location known to all near the storage area. • Clean up any spilled pesticides. Keep pesticide contaminated waste materials in designated covered and contained areas. • The pesticide application equipment must be capable of immediate shutoff in the event of an emergency. • Spraying pesticides within 100 feet of open waters including wetlands, ponds, and rivers, streams, creeks, sloughs and any drainage ditch or channel that leads to open water may have additional regulatory requirements beyond just following the pesticide product label. Additional requirements may include: • Obtaining a discharge permit from Ecology. • Obtaining a permit from the local jurisdiction. • Using an aquatic labeled pesticide. Volume IV - Source Control BMPs – December 2014 2-24 • Flag all sensitive areas including wells, creeks, and wetlands prior to spraying. • Post notices and delineate the spray area prior to the application, as required by the local jurisdiction or by Ecology. • Conduct spray applications during weather conditions as specified in the label direction and applicable local and state regulations. Do not apply during rain or immediately before expected rain. Recommended Additional Operational BMPs for the use of pesticides: • Consider alternatives to the use of pesticides such as covering or harvesting weeds, substitute vegetative growth, and manual weed control/moss removal. • Consider the use of soil amendments, such as compost, that are known to control some common diseases in plants, such as Pythium root rot, ashy stem blight, and parasitic nematodes. The following are three possible mechanisms for disease control by compost addition (USEPA Publication 530-F-9-044): 1. Successful competition for nutrients by antibiotic production; 2. Successful predation against pathogens by beneficial microorganism; and 3. Activation of disease-resistant genes in plants by composts. Installing an amended soil/landscape system can preserve both the plant system and the soil system more effectively. This type of approach provides a soil/landscape system with adequate depth, permeability, and organic matter to sustain itself and continue working as an effective stormwater infiltration system and a sustainable nutrient cycle. • Once a pesticide is applied, evaluate its effectiveness for possible improvement. Records should be kept showing the effectiveness of the pesticides considered. • Develop an annual evaluation procedure including a review of the effectiveness of pesticide applications, impact on buffers and sensitive areas (including potable wells), public concerns, and recent toxicological information on pesticides used/proposed for use. If individual or public potable wells are located in the proximity of commercial pesticide applications, contact the regional Ecology hydrogeologist to determine if additional pesticide application control measures are necessary. • Rinseate from equipment cleaning and/or triple-rinsing of pesticide containers should be used as product or recycled into product. For more information, contact the Washington State University (WSU) Extension Home-Assist Program, (253) 445-4556, or Bio-Integral Resource Center (BIRC), P.O. Box 7414, Berkeley, CA.94707, or EPA to Volume IV - Source Control BMPs – December 2014 2-25 obtain a publication entitled “Suspended, Canceled, and Restricted Pesticides” which lists all restricted pesticides and the specific uses that are allowed. Applicable Operational BMPs for Vegetation Management: • Use at least an eight-inch "topsoil" layer with at least 8 percent organic matter to provide a sufficient vegetation-growing medium. Amending existing landscapes and turf systems by increasing the percent organic matter and depth of topsoil can substantially improve the permeability of the soil, the disease and drought resistance of the vegetation, and reduce fertilizer demand. This reduces the demand for fertilizers, herbicides, and pesticides. Organic matter is the least water-soluble form of nutrients that can be added to the soil. Composted organic matter generally releases only between 2 and 10 percent of its total nitrogen annually, and this release corresponds closely to the plant growth cycle. Return natural plant debris and mulch to the soil, to continue recycling nutrients indefinitely. • Select the appropriate turfgrass mixture for the climate and soil type. Certain tall fescues and rye grasses resist insect attack because the symbiotic endophytic fungi found naturally in their tissues repel or kill common leaf and stem-eating lawn insects. However, they do not, repel root-feeding lawn pests such as Crane Fly larvae, and are toxic to ruminants such as cattle and sheep. The fungus causes no known adverse effects to the host plant or to humans. Endophytic grasses are commercially available; use them in areas such as parks or golf courses where grazing does not occur. Local agricultural or gardening resources such as Washington State University Extension office can offer advice on which types of grass are best suited to the area and soil type. • Use the following seeding and planting BMPs, or equivalent BMPs to obtain information on grass mixtures, temporary and permanent seeding procedures, maintenance of a recently planted area, and fertilizer application rates: Temporary and Permanent Seeding, Mulching, Plastic Covering, and Sodding as described in Volume II. • Adjusting the soil properties of the subject site can assist in selection of desired plant species. For example, design a constructed wetland to resist the invasion of reed canary grass by layering specific strata of organic matters (e.g., composted forest product residuals) and creating a mildly acidic pH and carbon-rich soil medium. Consult a soil restoration specialist for site-specific conditions. • Aerate lawns regularly in areas of heavy use where the soil tends to become compacted. Conduct aeration while the grasses in the lawn are growing most vigorously. Remove layers of thatch greater than ¾-inch deep. Volume IV - Source Control BMPs – December 2014 2-26 • Mowing is a stress-creating activity for turfgrass. Grass decreases its productivity when mown too short and there is less growth of roots and rhizomes. The turf becomes less tolerant of environmental stresses, more disease prone and more reliant on outside means such as pesticides, fertilizers, and irrigation to remain healthy. Set the mowing height at the highest acceptable level and mow at times and intervals designed to minimize stress on the turf. Generally mowing only 1/3 of the grass blade height will prevent stressing the turf. Irrigation: • The depth from which a plant normally extracts water depends on the rooting depth of the plant. Appropriately irrigated lawn grasses normally root in the top 6 to 12 inches of soil; lawns irrigated on a daily basis often root only in the top 1 inch of soil. Improper irrigation can encourage pest problems, leach nutrients, and make a lawn completely dependent on artificial watering. The amount of water applied depends on the normal rooting depth of the turfgrass species used, the available water holding capacity of the soil, and the efficiency of the irrigation system. Consult with the local water utility, Conservation District, or Cooperative Extension office to help determine optimum irrigation practices. Fertilizer Management: • Turfgrass is most responsive to nitrogen fertilization, followed by potassium and phosphorus. Fertilization needs vary by site depending on plant, soil, and climatic conditions. Evaluation of soil nutrient levels through regular testing ensures the best possible efficiency and economy of fertilization. For details on soils testing, contact the local Conservation District, a soils testing professional, or a Washington State University Extension office. • Apply fertilizers in amounts appropriate for the target vegetation and at the time of year that minimizes losses to surface and ground waters. Do not fertilize when the soil is dry. Alternatively, do not apply fertilizers within three days prior to predicted rainfall. The longer the period between fertilizer application and either rainfall or irrigation, the less fertilizer runoff occurs. • Use slow release fertilizers such as methylene urea, IDBU, or resin coated fertilizers when appropriate, generally in the spring. Use of slow release fertilizers is especially important in areas with sandy or gravelly soils. • Time the fertilizer application to periods of maximum plant uptake. Ecology generally recommends application in the fall and spring, although Washington State University turf specialists recommend four fertilizer applications per year. Volume IV - Source Control BMPs – December 2014 2-27 • Properly trained persons should apply all fertilizers. Apply no fertilizer at commercial and industrial facilities, to grass swales, filter strips, or buffer areas that drain to sensitive water bodies unless approved by the local jurisdiction. Integrated Pest Management An IPM program might consist of the following steps: Step 1: Correctly identify problem pests and understand their life cycle Step 2: Establish tolerance thresholds for pests. Step 3: Monitor to detect and prevent pest problems. Step 4: Modify the maintenance program to promote healthy plants and discourage pests. Step 5: Use cultural, physical, mechanical or biological controls first if pests exceed the tolerance thresholds. Step 6: Evaluate and record the effectiveness of the control and modify maintenance practices to support lawn or landscape recovery and prevent recurrence. For an elaboration of these steps, refer to Appendix IV-F. S412 BMPs for Loading and Unloading Areas for Liquid or Solid Material Description of Pollutant Sources: Operators typically conduct loading/unloading of liquid and solid materials at industrial and commercial facilities at shipping and receiving, outside storage, fueling areas, etc. Materials transferred can include products, raw materials, intermediate products, waste materials, fuels, scrap metals, etc. Leaks and spills of fuels, oils, powders, organics, heavy metals, salts, acids, alkalis, etc. during transfer may cause stormwater contamination. Spills from hydraulic line breaks are a common problem at loading docks. Pollutant Control Approach: Cover and contain the loading/unloading area where necessary to prevent run-on of stormwater and runoff of contaminated stormwater. Applicable Operational BMPs: At All Loading/ Unloading Areas: • A significant amount of debris can accumulate at outside, uncovered loading/unloading areas. Sweep these surfaces frequently to remove loose material that could contaminate stormwater. Sweep areas temporarily covered after removal of the containers, logs, or other material covering the ground. • Place drip pans, or other appropriate temporary containment device, at locations where leaks or spills may occur such as hose connections, hose reels and filler nozzles. Always use drip pans when making and Volume IV - Source Control BMPs – December 2014 2-37 Recommended Treatment BMPs: Install biofiltration swales and filter strips – (See Chapter 9, Volume V) to treat roadside runoff wherever practicable and use engineered topsoils wherever necessary to maintain adequate vegetation. These systems can improve infiltration and stormwater pollutant control upstream of roadside ditches. S417 BMPs for Maintenance of Stormwater Drainage and Treatment Systems Description of Pollutant Sources: Facilities include roadside catch basins on arterials and within residential areas, conveyance systems, detention facilities such as ponds and vaults, oil/water separators, biofilters, settling basins, infiltration systems, and all other types of stormwater treatment systems presented in Volume V. Oil and grease, hydrocarbons, debris, heavy metals, sediments and contaminated water are found in catch basins, oil and water separators, settling basins, etc. Pollutant Control Approach: Provide maintenance and cleaning of debris, sediments, and oil from stormwater collection, conveyance, and treatment systems to obtain proper operation. Applicable Operational BMPs: Maintain stormwater treatment facilities per the operations and maintenance (O&M) procedures presented in Section 4.6 of Volume V in addition to the following BMPs: • Inspect and clean treatment BMPs, conveyance systems, and catch basins as needed, and determine necessary O&M improvements. • Promptly repair any deterioration threatening the structural integrity of stormwater facilities. These include replacement of clean-out gates, catch basin lids, and rock in emergency spillways. • Ensure adequacy of storm sewer capacities and prevent heavy sediment discharges to the sewer system. • Regularly remove debris and sludge from BMPs used for peak-rate control, treatment, etc. and discharge to a sanitary sewer if approved by the sewer authority, or truck to an appropriate local or state government approved disposal site. • Clean catch basins when the depth of deposits reaches 60 percent of the sump depth as measured from the bottom of basin to the invert of the lowest pipe into or out of the basin. However, in no case should there be less than six inches clearance from the debris surface to the invert of the lowest pipe. Some catch basins (for example, WSDOT Type 1L basins) may have as little as 12 inches sediment storage below the invert. These catch basins need frequent inspection and cleaning to prevent scouring. Where these catch basins are part of a stormwater collection and treatment system, the system Volume IV - Source Control BMPs – December 2014 2-38 owner/operator may choose to concentrate maintenance efforts on downstream control devices as part of a systems approach. • Clean woody debris in a catch basin as frequently as needed to ensure proper operation of the catchbasin. • Post warning signs; “Dump No Waste - Drains to Ground Water,” “Streams,” “Lakes,” or emboss on or adjacent to all storm drain inlets where possible. • Disposal of sediments and liquids from the catch basins must comply with “Recommendations for Management of Street Wastes” described in Appendix IV-G of this volume. Additional Applicable BMPs: Select additional applicable BMPs from this chapter depending on the pollutant sources and activities conducted at the facility. Those BMPs include: • S425 BMPs for Soil Erosion and Sediment Control at Industrial Sites • S427 BMPs for Storage of Liquid, Food Waste, or Dangerous Waste Containers • S406 BMPs for Spills of Oil and Hazardous Substances • S410 BMPs for Illicit Connections to Storm Drains • S430 BMPs for Urban Streets S418 BMPs for Manufacturing Activities - Outside Description of Pollutant Sources: Manufacturing pollutant sources include outside process areas, stack emissions, and areas where manufacturing activity has taken place in the past and significant exposed pollutant materials remain. Pollution Control Approach: Cover and contain outside manufacturing and prevent stormwater run-on and contamination, where feasible. Applicable Operational BMP: • Sweep paved areas regularly, as needed, to prevent contamination of stormwater. • Alter the activity by eliminating or minimizing the contamination of stormwater. • Applicable Structural Source Control BMPs: Enclose the activity (see Figure 2.2.6): If possible, enclose the manufacturing activity in a building. • Cover the activity and connect floor drains to a sanitary sewer, if approved by the local sewer authority. Berm or slope the floor as needed to prevent drainage of pollutants to outside areas. (Figure 2.2.7) Volume IV - Source Control BMPs – December 2014 2-57 • Stock cleanup materials, such as brooms, dustpans, and vacuum sweepers near the storage area. S430 BMPs for Urban Streets Description of Pollutant Sources: Urban streets can be the source of vegetative debris, paper, fine dust, vehicle liquids, tire and brake wear residues, heavy metals (lead and zinc), soil particles, ice control salts, domestic wastes, lawn chemicals, and vehicle combustion products. Street surface contaminants contain significant concentrations of particle sizes less than 250 microns (Sartor and Boyd, 1972). Pollutant Control Approach: Conduct efficient street sweeping where and when appropriate to minimize the contamination of stormwater. Do not wash street debris into storm drains. Facilities not covered under the Industrial Stormwater General Permit may consider a minimum amount of water washing of streets. All facilities must comply with their local stormwater requirements for discharging to storm sewers. Municipal NPDES permittees are required to limit street wash water discharges and may have special conditions or treatment requirements. Recommended BMPs: • For maximum stormwater pollutant reductions on curbed streets and high volume parking lots, use efficient vacuum sweepers. Note: High-efficiency street sweepers utilize strong vacuums and the mechanical action of main and gutter brooms combined with an air filtration system that only returns clean air to the atmosphere (i.e., filters very fine particulates). They sweep dry and use no water since they do not emit any dust. High-efficiency vacuum sweepers have the capability of removing, 80 percent or more of the accumulated street dirt particles whose diameters are less than 250 microns (Sutherland, 1998). This assumes pavements under good condition and reasonably expected accumulation conditions. • For moderate stormwater pollutant reductions on curbed streets use regenerative air sweepers or tandem sweeping operations. Note: A tandem sweeping operation involves a single pass of a mechanical sweeper followed immediately by a single pass of a vacuum sweeper or regenerative air sweeper. − A regenerative air sweeper blows air down on the pavement to entrain particles and uses a return vacuum to transport the material to the hopper. Volume IV - Source Control BMPs – December 2014 2-58 − These operations usually use water to control dust. This reduces their ability to pick up fine particulates. These types of sweepers have the capability of removing approximately 25 to 50 percent of the accumulated street dirt particles whose diameters are less than 250 microns. (Sutherland, 1998). This assumes pavements under good conditions and typical accumulation conditions. • For minimal stormwater pollutant reductions on curbed streets use mechanical sweepers. − Note: The industry refers to mechanical sweepers as broom sweepers and uses the mechanical action of main and gutter brooms to throw material on a conveyor belt that transports it to the hopper. − These sweepers usually use water to control dust. This reduces their ability to pick up fine particulates. Mechanical sweepers have the capability of removing only 10 to 20 percent of the accumulated street dirt particles whose diameters are less than 250 microns (Sutherland, 1998). This assumes pavements under good condition and the most favorable accumulation conditions. • Conduct vacuum sweeping at optimal frequencies. Optimal frequencies are those scheduled sweeping intervals that produce the most cost-effective annual reduction of pollutants normally found in stormwater and can vary depending on land use, traffic volume and rainfall patterns. • Train operators in those factors that result in optimal pollutant removal. These factors include sweeper speed, brush adjustment and rotation rate, sweeping pattern, maneuvering around parked vehicles, and interim storage and disposal methods. • Consider the use of periodic parking restrictions in low to medium density single-family residential areas to ensure the sweeper’s ability to sweep along the curb. • Establish programs for prompt vacuum sweeping, removal, and disposal of debris from special events that will generate higher than normal loadings. • Disposal of street sweeping solids must comply with “Recommendations for Management of Street Wastes” described in Appendix IV-G of this volume. • Inform citizens about eliminating yard debris, oil and other wastes in street gutters to reduce street pollutant sources.