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Maintenance Report 2022.10.07 TAHOMA TERRA RESIDENTIAL 21-041 Maintenance & Source Control Manual Yelm Project # MU 2021.0024 Prepared for: Copper Ridge, LLC PO Box 73790 Puyallup, WA 98373 (253) 820-7853 evan@soundbuilthomes.com Report Date: October 7, 2022 Prepared by: Jared Greisz, EIT Reviewed by: Chloe McIntyre, PE HATTON GODAT PANTIER 3910 Martin Way E., Suite B Olympia, WA 98506 (360) 943-1599 Project No: 21-041 Project Name: TAHOMA TERRA RESIDENTIAL RESIDENTIAL H:\Office\JOBS\2021\21-041 Tahoma Terra 7-8\PERMIT\Drainage\Maintenance Report 2022.07.06.docx TABLE OF CONTENTS Introduction ................................................................................................................... 1 What Is Stormwater Runoff? ............................................................................................................ 1 What Is a Storm Drain System and How Does It Work? ................................................................. 1 What Does Stormwater Runoff Have to Do With Water Quality? .................................................... 1 Section 1 – Project Description ................................................................................... 1 Section 2 – Maintenance Importance and Intent ........................................................ 2 Section 3 – Responsible Parties .................................................................................. 2 Section 4 – Facilities Requiring Maintenance ............................................................. 3 Section 5 – Maintenance Instructions ......................................................................... 3 How to Use the Stormwater Facility Maintenance Guide ................................................................ 3 Included in This Guide ..................................................................................................................... 4 Facility Key ....................................................................................................................................... 4 Site Plan ........................................................................................................................................... 5 Quick List ....................................................................................................................................... 10 Resource Listing ............................................................................................................................ 11 Section 6 – Vegetation Management ......................................................................... 12 Landscape Design and Maintenance ............................................................................................. 12 Pest Control ................................................................................................................................... 15 Pesticide Management................................................................................................................... 15 Section 7 – Pollution Source Control Measures ....................................................... 17 Purpose .......................................................................................................................................... 17 Materials Used and Wastes Generated ......................................................................................... 17 General Principals of Pollution Prevention..................................................................................... 17 Appendix A – Maintenance Checklists ...................................................................... 21 Log Sheet ....................................................................................................................................... 21 TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 1 Introduction What Is Stormwater Runoff? When urban and suburban development covers the land with buildings, streets and parking lots, much of the native topsoil, duff, trees, shrubs and grass are replaced by asphalt and concrete. Rainfall that would have soaked directly into the ground instead stays on the surface as stormwater runoff making its way into storm drains (including man-made pipes, ditches or swale networks), stormwater ponds, surface and groundwater and, eventually, to Puget Sound. What Is a Storm Drain System and How Does It Work? The storm drain system for most developments includes measures to carry, store, cleanse and release the stormwater. Components work together to reduce the impacts of development on the environment. Impacts can include flooding that results in property damage and blocked emergency routes, erosion that can cause damage to salmon spawning habitat and pollution that harms fish and/or drinking water supplies. The storm drain system provides a safe method to carry stormwater to the treatment and storage area. Filter Strips and ponds filter pollutants from the stormwater by physically settling out particles, chemically binding pollutants to pond sediments and biologically converting pollutants to less harmful compounds. Ponds also store treated water, releasing it gradually to a nearby stream or to groundwater. What Does Stormwater Runoff Have to Do With Water Quality? Stormwater runoff must be treated because it carries litter, oil, gasoline, fertilizers, pesticides, pet wastes, sediments and anything else that can float, dissolve or be swept along by moving water. Left untreated, polluted stormwater can reach nearby waterways where it can harm and even kill aquatic life. It can also pollute groundwater to the extent that it requires treatment before it is suitable for drinking. Nationally, stormwater is recognized as a major threat to water quality. Remember to keep everything out of stormwater systems except the rainwater they are designed to collect. Section 1 – Project Description The Tahoma Terra Residential project is located south of the intersection with Tahoma Blvd and Dotson St in the City of Yelm. The site is located in Section 24, Township 17, Range 1E, W.M. on tax parcel numbers 78640000015, 78640000016, 78640000017, and 78640000018. The Tahoma Terra Residential project proposes to construct 234 new single-family homes over 40.81 acres, 334,105 square feet of frontage improvements, and required drainage, landscaping, sewer and water improvements. Stormwater mitigation for this project will include runoff collection from the new impervious surfaces via catch basins and then conveyance in storm piping to three new stormwater facilities: A wet pond and detention pond in the southwest corner, bioretention cell and retention pond in the north, and another bioretention cell and retention pond in the southeast. Additionally, an existing TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 2 bioretention cell and detention pond built for the multifamily homes project north of the eastern portion of the site, will also be used. Section 2 – Maintenance Importance and Intent The importance of maintenance for the proper functioning of stormwater control facilities cannot be over-emphasized. A substantial portion of failures (clogging of filters, resuspension of sediments, loss of storage capacity, etc.) are due to inadequate maintenance. Stormwater BMP maintenance is essential to ensure that BMPs function as intended throughout their full life cycle. The fundamental goals of maintenance activities are to ensure the entire flow regime and treatment facilities designed for this site continue to fully function. For this site these include: • Maintain designed stormwater detention/retention volume • Maintain ability of storm facility to attenuate flow rates • Maintain ability to safely convey design stormwater flows • Maintain ability to treat stormwater runoff quality • Preserve soil and plant health, as well as stormwater flow contact with plant and soil systems • Clearly identify systems so they can be protected • Keep maintenance costs low • Prevent large-scale or expensive stormwater system failures • Prevent water quality violations or damage to downstream properties The intent of this section and manual is to pass on to the responsible party(s) all the information critical to understand the design of the system, risks and considerations for proper use, suggestions for maintenance frequencies, and cost so that realistic budgets can be established. Section 3 – Responsible Parties All property owners within this subdivision are members of the Homeowners’ Association (HOA). The HOA is responsible for many of the mitigation measures discussed herein. However, most of the responsibility for protection of our water resources lies with each individual property owner. The common areas within the subdivision will be managed by the HOA and they may hire outside contractors where needed. This Maintenance and Source Control Plan is recorded against the title for all properties within the subdivision. Enforcement of the recommendations lies with the underlying jurisdictions, and the property owners and HOA should strive to incorporate them in their daily activities. All parties below shall read the Maintenance and Source Control Plan: TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 3 Specific Responsibilities Landscape Maintenance Developer / HOA and Maintenance Contractors / Homeowners Common Facilities Developer / HOA and Maintenance Contractors / Homeowners Stormwater Facilities Developer / HOA and Maintenance Contractors Household activities Homeowners (proper landscape maintenance & disposal of products) Section 4 – Facilities Requiring Maintenance This Maintenance and Source Control Manual was designed to explain how stormwater facilities work and provide user-friendly, straightforward guidance on facility maintenance. Stormwater facilities on this site include roof drains, cleanouts, catch basins, storm piping, bioretention facilities, retention ponds, a wet pond, detention ponds with control structures and energy dissipators, trash racks, fencing, and access roads. All stormwater facilities located in the public right-of-way are maintained by City of Yelm. This includes catch basins and storm piping. The HOA and individual property owners are responsible for roof drains, cleanouts, catch basins, storm piping, bioretention facilities, retention ponds, a wet pond, detention ponds with control structures and energy dissipators, trash racks, fencing, and access roads. Runoff from roof areas is collected in gutters and conveyed to roof drain lines. Cleanouts provide access for maintenance to the roof drain lines. Roof drain lines convey runoff from the buildings to catch basins located through the site. Catch basins collect stormwater runoff from on-site paved areas and stormwater piping will convey stormwater to one of four onsite stormwater facilities. See the Drainage Report submitted as part of the Drainage Control Plan for a more detailed explanation of the onsite stormwater facility design and operation. Section 5 – Maintenance Instructions The stormwater system owner(s) must review and apply the maintenance requirements contained in the Stormwater Maintenance Agreement. The owner shall inspect all stormwater facilities annually and maintain them at their own expense. The owner shall complete and file an inspection and maintenance form with the city following inspection and maintenance. When inspections indicate a maintenance need, the owner shall complete all maintenance within one year for typical maintenance of facilities, within six months for catch basins, and within two years for maintenance that requires capital construction of greater than $25,000. How to Use the Stormwater Facility Maintenance Guide This Maintenance & Source Control Manual includes a Site Plan specific to your development and a Facility Key that identifies the private stormwater facilities you are responsible for maintaining. A TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 4 “Quick List” of maintenance activities has also been included to help you identify the more routine needs of your facility. Included in This Guide • Comprehensive Maintenance Checklists that provide specific details on required maintenance located in Appendix B • Pollution Prevention Tips that list ways to protect water quality and keep storm drain systems functioning smoothly • Resources to provide more information and technical assistance Facility Key The stormwater facilities in your neighborhood are comprised of the following elements: Type of Feature and Checklist Name Location on Site Plan Wet Pond 1 Trash Rack 2 Catch Basins 3 Storm Piping 4 Bioretention Cell 5 Detention Pond 6 Retention Pond 7 Energy Dissipator 8 Control Structure 9 Dispersion Trench 10 Fencing 11 TAHOMA TERRA PHASE 2 - DIVISION 7 & 8 TAHOMA BLVD SE, YELM, WA 98597 SEE ENLARGED MAINTENANCE MAINTENANCE MAINTENANCE MAINTENANCE FACILITY MAP - B FACILITY MAP - C FACILITY MAP - D FACILITY MAP - A MAINTENANCE FACILITY KEY TAHOMA TERRA PHASE 2 - DIVISION 7 & 8 TAHOMA BLVD SE, YELM, WA 98597 1110 T] A T ENLARGED MAINTENANCE FACILITY MAP - A TAHOMA TERRA PHASE 2. - DIVISION 7 & 8 TA WnM A RI Vn QF' VPI M WA QQr%"Q7 It Mil TAHOMA TERRA PHASE 2. - DIVISION 7 & 8 � F�lM f i i A i Z 1 T\ i t 1T\ I►T� � �Tr i i� t >< i >< A A r� A �i ENLARGED MAINTENANCE FACILITY MAP - C: TAHOMA TERRA PHASE II - DN. S MF 14301 TAHOMA BLVD SE, YELM, WA 98597 , sE � ,- s A gL�N.T.S. 2 ENLARGED MAINTENANCE FACI U MAP - D TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 10 Quick List The following is an abbreviated checklist of the most common types of maintenance required. Please go over this checklist after heavy rains. The list represents minimum maintenance to be performed and should be completed in conjunction with the other checklists for an effective maintenance program. More comprehensive maintenance checklists specific to each onsite stormwater facility are included in Appendix B.  Inspect catch basin grates to see that they are not clogged or broken. Remove twigs, leaves or other blockages. Contact the local jurisdiction to replace the grate if it is broken.  Inspect inlet and outlet pipes for blockages. Clear all blockages.  Inspect filter strip, swale and pond walls for erosion or caved in areas.  Inspect riprap (rocks) at the inlets and outlets of culverts and other pipes. If they are silted in or eroded away, replace them. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 11 Resource Listing If you suspect a problem exists, please contact your local jurisdiction at one of the numbers below and ask for Technical Assistance. CONTACT NUMBERS City of Yelm Public Works (360) 458-8406 City of Yelm Spill Reporting Hotline (360) 458-8406 Thurston County Environmental Health – Hazardous Waste Disposal (360) 754-4111 Thurston County Environmental Health – Solid Waste Disposal (360) 789-5136 WSU Thurston Co. Extension (360) 786-5445 DEVELOPER INFORMATION Copper Ridge, LLC PO Box 73790, Puyallup, WA 98373 (253) 820-7853 ENGINEER’S INFORMATION Hatton Godat Pantier 3910 Martin Way E., Suite B Olympia, WA 98506 (360) 943-1599 TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 12 Section 6 – Vegetation Management The homeowners, HOA, and Landscape Maintenance Contractor are responsible for applying integrated pest management control techniques to maintain landscaped areas. This includes pest control, pesticide management, and watering. Reference the construction drawings in the Drainage Control Plan for detailed information on landscaping throughout the site. Landscape Design and Maintenance The following techniques shall be applied: 1. Native Plants: One of the best methods of reducing impacts to water resources is by using landscaping materials that do not require extensive care. Native plants have adapted themselves to our region, particularly their root structure and water needs. These plants have also built tolerances over the centuries to local pests and disease. By using native plants in the landscape, we are less likely to need fertilizers, herbicides, and pesticides. Native plants are also more tolerant of drought conditions and typically require less water. The Developer shall install the native plant materials called out on the Landscape Plan. Additional plantings may be installed by individual homeowners/property owners. Native plants come in all shapes and sizes so there is probably one that will fit into your landscape plans. There are deciduous and evergreen varieties of trees, shrubs and groundcovers. Some suggested species of native plants are listed below. Contact your local garden supply store for more ideas on use of native plants in your garden. Evergreen Plants: Trees: Western red cedar, Douglas-fir, Western hemlock Shrubs: rhododendron, evergreen huckleberry, tall Oregon-grape Ferns: lady fern, sword fern, dear fern Groundcover: manzanita, kinnikinnik, common juniper Deciduous Plants: Trees: big leaf maple, Pacific dogwood, bitter cherry Shrubs: western azalea, Nootka rose, red huckleberry 2. Grasses for Lawns: Both the developer and individual homeowners/property owners will install lawns. The lawn is a major component of the landscape. Selection of a grass well suited to our area is an important step in reducing the impact to water resources. The National Turfgrass Evaluation studies various types of grasses for their resistance to insects, drought tolerance, seasonal appearance, density, the strength of their sod and leaf texture. Based upon these characteristics, specific grass types are recommended for specific areas throughout the country. Fescue and perennial rye grass are recommended for this area. 3. Mulching: Use of native plants will greatly reduce the need for fertilizer. Use of mulch may eliminate the need altogether. Mulch acts as a physical barrier to weeds and is an excellent alternative to herbicides. Mulch can be compost, bark or wood chips, or leaves and grass clippings. It should be spread around the base of plants and within flowerbeds. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 13 The recommended depth of mulch varies between plant varieties but should typically be 2- to 4 inches. 4. Use of Fertilizers: Proper use of fertilizers yields better plants and reduces negative impacts to our water resources. Fertilizers typically contain high levels of nitrogen and phosphorus, both of which can damage ground and surface waters. The following are a few tips to optimize the use of fertilizers in your garden. 5. Soil Testing: The first step in fixing a problem is to know what that problem is. Therefore, before applying any fertilizer, test your soil. Existing soil conditions, particularly nitrogen, phosphorus, potassium and pH levels, can be easily determined by using kits available at garden stores or from the WSU Cooperative Extension. Applying fertilizer before knowing the components of the soil could lead to over loading certain areas that may impact our water resources. 6. Proper Fertilization: Proper fertilization is important in maintaining a healthy lawn that resists environmental stress, including competition with weeds and moss and drought stress. Because Spring and Fall are periods of optimal growth, these are the most important times to fertilize. The use of slow release fertilizers is recommended. Natural organic and synthetic organic fertilizers (such as IBDU, sulfur or polymer coated urea, or methylene urea) behave similarly once they are applied to the soil. Although some people feel that natural organic fertilizers provide added benefits to soil health, research has not shown this to be true as a general rule. The natural organic nutrient sources in these products are often supplemented with synthetic plant nutrients anyway. The most important thing to remember is to use a slow release fertilizer. Extensive research around the country has shown that when these materials are applied properly there is very little risk of surface or groundwater contamination, and they provide an even feeding, which is better for your lawn. Remember to sweep granules off pavement to prevent washing into storm drains. Many soils can benefit from the use of organic fertilizers such as compost or peat. These substances add nutrients to soil and increase the porosity of the soil as well as its ability to hold water. For lots with additional restrictions regarding phosphorus contamination to stormwater runoff, phosphorus-free fertilizers must be used for all lawn and landscaping activities. 7. Fertilizing the Lawn: Turf fertilization practices for the entire year are built around what is done in the fall. Apply fertilizer in early to mid-September to promote regrowth from summer stress. Another application in November is important in keeping the grass competitive with moss through the winter. If you fertilize in November, you probably don't need an early spring fertilization. If not, your lawn will probably be ready for fertilizer in the spring. Again, use a slow release fertilizer so that you don't promote a big flush of growth. Fertilize again in early June so that the grass has the nutrients it needs to grow at a moderate rate through the summer stress period. If you want to maintain a lawn of moderate quality, a minimum of three fertilizations through the year is needed. Additional light fertilizations can be added if you are looking for a higher quality lawn. In general, you should apply no more than one pound of actual TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 14 fertilizer nitrogen per 1000 square feet at a time, although this rate can be increased to 1.5 pounds in the fall when using slow release products. (If the fertilizer analysis is 24-4-12, for example, it contains 24% nitrogen. To apply 1 pound of Nitrogen per 1,000 square feet, apply 4.2 pounds of fertilizer: 1 ÷ 0.24 = 4.2). Return clippings (grasscycle) when you mow to recycle nutrients into the lawn. Use mulching mowers to return grass clippings directly to the lawn. Essential nutrients from the decomposed grass can then be retained in the soil thereby reducing the need for fertilizer. 8. Water Before Fertilizing: Water plants and lawns before fertilizing. Water enough to dampen the ground thoroughly, but not enough to cause surface runoff. Dampening the soil prevents fertilizer from being washed from the surface of dry soil in the first rain or watering after application. 9. Proper Watering: Proper watering can help build strong plants resistant to drought, pests and disease. Water infrequently but enough to dampen soil down to 10 inches. Be careful not to water so rapidly that water runs off the surface. Infrequent watering promotes shallow root depths making the plants susceptible to damage during periods of drought. Unhealthy plants are easy targets for pests and disease. Also, water during early morning hours rather than during the day or at night. Irrigating during the day loses a sizable amount of water to the atmosphere through evaporation. Watering at night can lead to mold and fungi growth on plants left damp over a cool night. The irrigation system should be programmed to provide about 1” of water per week during the growing season. This includes normal precipitation. The system shall be provided with rain sensors which can suspend watering, and soil moisture sensors which can automatically adjust watering intervals and run times (e.g. Cycle-Soak). 10. Weed Control: Use of mechanical means for weed control is typically less attractive due to the cost. However, non-chemical controls for transient and invasive weed problems shall be emphasized in the IPM program in efforts to reduce overall environmental impacts. The quick establishment of a thick, healthy, native or ornamental groundcover planting will reduce the need for weed control. Implement measures to reduce this establishment time by increasing plant spacing, adding/replacing groundcovers, and using groundcover species that are spreading or widely-mounding. Reduce compaction to mulch to encourage groundcover establishment and cover-rate. The initial establishment of groundcovers may require more weed control. When the need for chemical treatment is necessary over woody groundcovers, carefully determine the target broadleaf or grass species, and choose a selective herbicide that specifically labeled for application over the type of planting. Use labeled rates and ensure proper training for applicators and handlers for proper coverage. Reduce the need for selective broadleaf herbicide treatments in lawn areas by using clean soil amendment and turf seed, proper installation, and appropriate nutrient applications for the lawn area. Use selective mechanical measures to remove broadleaf weeds in newly seeded lawn areas. Proper watering and mowing height will increase vigor and reduce broadleaf pressure in lawn areas established with turf. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 15 Pest Control Some of the tactics that can be used to decrease or eliminate the use of pesticides include: 1. Use of Natural Predators or Pathogens: Because chemical sprays generally kill many beneficial insects instead of just the target pest, it may be necessary to introduce natural predators back into the garden. Ladybugs, lacewings, predatory wasps and nematodes are all commercially available. Garter snakes and toads are also predators and should not be eliminated from the garden. There are some bacteria, viruses and insect parasites that are specific to pests and will not harm other insects or animals. A commonly used bacterium in the Puget Sound area is Bacillus thuringiensis (Bt), which is intended to control infestations of tent caterpillars. 2. Habitat Changes: Many times a change of habitat can control pest infestations. Removal of any item that will pond water, like buckets or tires, can cut down on the mosquito population by removing a convenient location for them to breed in. Removing last year’s leaves from under rose bushes can cut down on the incidence of mildew and blackspot, as these fungi overwinter in dead leaves. 3. Timing: Crops that can overwinter (such as leeks or carrots) should be planted in the fall. This gives them time to become established before pests arrive in the spring. 4. Mechanical: Many eggs, larvae, cocoons and adult insects can be removed by hand. Be sure that the insect is properly identified prior to removing it so those beneficial insects are not destroyed in error. Drowning insects in plain water or spraying them with soapy water are alternatives to squashing them. 5. Resistant Plants: Plants that are native to this area are often more resistant to pests and tolerant of the climate than are introduced plants. Many plant cultivars have been developed which are resistant to such diseases as verticilium wilt and peach leaf curl. Grass seed mixes are also available for lawns that need much less watering, mowing and chemical use. 6. Growing Conditions: Plants, such as hostas, that require some shade are more susceptible to pests when they are growing in the sun. Improperly fertilized or watered plants are less vigorous in growth and tend to attract pests. Plants that prefer an acid soil, such as azaleas, will perform better and be less susceptible to pests when they are grown in soil with the proper pH. 7. Chemicals: Chemicals are a small part of the IPM plan and should be applied only as needed after reviewing all other alternatives. Avoid the use of broad-spectrum pesticides which may kill beneficial insects. Pesticide Management When use of a chemical is the best or only option, follow the basic guidelines below. Maintenance Contractors shall be licensed commercial applicators and shall always follow the Pesticide Label. 1. Know your target pest before spraying. Use the pesticide according to the manufacturer's instructions and buy only the needed quantity. Many pesticides have a limited shelf life TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 16 and may be useless or degrade into even more toxic compounds if stored for extended periods of time. 2. Do not apply more than the specified amount. Overuse can be dangerous to your health as well as the health of wildlife and the environment. If more than one chemical can be used to control the pest, choose the least toxic. The word “caution” on the label means that the chemical is less toxic than one that is labeled “warning”. 3. Do not spray on windy days, in the morning of what will be a very hot day or when rain is likely. Herbicides can drift and injure valuable ornamental plants. Do not water heavily after application. Plants should be lightly watered before application to prevent burning of the foliage and to help evenly spread the chemical. 4. Never apply pesticides near streams, ponds or wetlands (exception: approved applications for aquatic weeds). Do not apply pesticides to bare eroded ground. Many pesticides bind to soil particles and can be easily carried into a stream or storm drain. 5. Pesticides should be stored well away from living areas. Ideally, the storage area should have a cement floor and be insulated from temperature extremes. Always keep pesticides in their original containers with labels intact. Labels often corrode and become illegible in this climate and may have to be taped onto the container. 6. Federal law now requires that all pesticides be labeled with the appropriate disposal method. Leftovers should never be dumped anywhere, including a landfill. Take unwanted pesticides to Hazo House located at the former landfill at 2420 Hogum Bay Road NE, Lacey. Call the Thurston County Hazardous Waste Section at (360) 867-2664 for more information. 7. Empty pesticide containers should be triple rinsed, and the rinse water used in the same manner as the product. Once containers are rinsed, they can be disposed of as regular garbage. 8. If a pesticide is spilled onto pavement, it can be absorbed using kitty litter or sawdust. The contaminated absorbent should be bagged, labeled and taken to Hazo House. 9. If the pesticide is spilled onto dirt, dig up the dirt, place it in a plastic bag and take it to Hazo House. 10. Many pest control companies and licensed applicators have access to pesticides that are more toxic than those available to the consumer. Check with the company before they spray indoors or outdoors to find out what spray they will be using and what precautions, if any, are necessary after the operator leaves. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 17 Section 7 – Pollution Source Control Measures Purpose Pollution source controls are actions taken by a person or business to reduce the contamination of stormwater runoff at its source. Controls, also called “best management practices” (BMPs) include: • Altering the activity (e.g., substitute non-toxic products, recycle used oil, route floor drains to sanitary sewer rather than storm sewer) • Enclosing or covering the activity (e.g., building a roof) • Segregating the activity (e.g., diverting runoff away from an area that is contaminated) • Routing runoff from the activity to a treatment alternative (e.g., a wastewater treatment facility, sanitary sewer, or stormwater treatment area) A Stormwater Pollution Source Control Checklist and Worksheet has been completed and is included in Appendix C of this Maintenance & Source Control Manual. The Stormwater Pollution Source Control Checklist and Worksheet identifies all of the activities that will occur at the project site as well as the source control BMPs which will be implemented to manage source contamination. Materials Used and Wastes Generated Generally, drives and parking areas are of particular concern. Because of heavy vehicle usage, the concentration of oil and grease in stormwater may exceed the Ecology guidelines of 10 mg/L. Although there are no local data to confirm this view, limited research in the San Francisco Bay area found the mean concentration of oil and grease in stormwater to exceed 10 mg/L. General Principals of Pollution Prevention This section describes the basic pollution prevention principles that every business and homeowner must consider. Most of these are common sense “housekeeping” types of solutions. With collective action by individuals and businesses throughout the region in implementing each of these principles, the improvement in water quality could be substantial. Although most of these principles are aimed at commercial or industrial activities, many items apply to individual residents as well. AVOID THE ACTIVITY OR REDUCE ITS OCCURRENCE If possible, avoid the activity or do it less frequently. Is there a substitute process or a different material available to get the job done? Can a larger run of a process be performed at one time, thus reducing the number of times per week or month it needs to be repeated? For instance, raw materials could be delivered close to the time of use instead of being stockpiled and exposed to the weather. Perhaps the site could avoid one solvent-washing step altogether. Apply lawn care chemicals following directions and only as needed. Many lawns are excessively fertilized. Do not apply herbicides right before it rains. Ecology or the Thurston County Department of Public Health and Social Services can provide pollution prevention assistance. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 18 MOVE ACTIVITIES UNDER SHELTER Sometimes it is fairly easy to move an activity indoors out of the weather. The benefits of this are twofold; preventing runoff contamination, and providing for easier, more controlled cleanup if a spill occurs. An example would be unloading and storing barrels of chemicals inside a garage area instead of doing it outside. Please be aware that moving storage areas indoors may require installation of fire suppression equipment or other building modifications as required by the International Building Code (IBC), the International Fire Code or local ordinances. CLEAN UP SPILLS QUICKLY Promptly contain and clean up solid and liquid pollutant leaks and spills on any exposed soil, vegetation, or paved area. Commercial spill kits are available, but readily available absorbents such as kitty litter also work well in many cases. Promptly repair or replace all leaking connections, pipes, hoses, valves, etc., which can contaminate stormwater. USE LESS MATERIAL Don’t buy or use more material than you really need. This not only helps keep potential disposal, storage, and pollution problems to a minimum, but will probably save money, too. USE THE LEAST TOXIC MATERIALS AVAILABLE Investigate the use of materials that are less toxic than what is used now. Perhaps a caustic-type detergent or a solvent could be replaced with a more environmentally friendly product. Such a change might allow the site to discharge process water to the sanitary sewer instead of paying for expensive disposal (contact the City of Yelm Wastewater Utility to find out about allowable sanitary sewer discharges and pretreatment permits). Remember that even if using a biodegradable product, nothing but uncontaminated water is allowed to enter the stormwater drainage system. CREATE AND MAINTAIN VEGETATED AREAS NEAR ACTIVITY LOCATIONS Vegetation of various kinds can help filter pollutants out of stormwater, so it is advisable to route stormwater through vegetated areas located near the activity. For instance, many parking lots contain grassy islands, typically formed in a “hump.” By creating those islands as depressions instead of humps, they can be used to treat runoff from the parking lot or roof. Also, don’t forget the erosion control benefits of vegetation at a site. LOCATE ACTIVITIES AS FAR AS POSSIBLE FROM SURFACE DRAINAGE PATHS Activities located as far as possible from known drainage paths, ditches, streams, other water bodies, and storm drains will be less likely to pollute, since it will take longer for material to reach the drainage feature. This gives more time to react to a spill, or if it is a “housekeeping” issue, may protect the local waters long enough for you to clean up the area around the activity. Don’t forget that groundwater protection is important throughout the region, no matter where the activity is located, so the actions taken on your site on a day-to-day basis are always important, even in dry weather. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 19 MAINTAIN STORMWATER DRAINAGE SYSTEMS Pollutants can concentrate over time in storm drainage structures such as catch basins, ditches, and storm drains. When a large storm event occurs, it can mobilize these pollutants and carry them to receiving waters. Develop and implement maintenance practices, inspections, and schedules for treatment facilities (e.g., detention ponds, oil/water separators, vegetated swales). Clean oils, debris, sludge, etc., from all BMP systems regularly, including catch basins, settling/detention basins, oil/water separators, boomed areas, and conveyance systems, to prevent the contamination of stormwater. Promptly repair or replace all substantially cracked or otherwise damaged paved secondary containment, high-intensity parking, and any other drainage areas that are subjected to pollutant material leaks or spills. Also repair or replace all leaking connections, pipes, hoses, valves, etc., which can contaminate stormwater. Requirements for cleaning stormwater facilities are discussed in Volume IV of the 2014 Ecology Manual, specifically BMP S417. Maintenance standards can be found in Chapter 3, Appendix 3B. REDUCE, REUSE, AND RECYCLE AS MUCH AS POSSIBLE Always look for ways to recycle instead of just disposing. This can save money as well as keep both hazardous and non-hazardous materials out of the landfills. Learn more about other businesses that have made process changes allowing recycling of chemicals by calling Ecology at 1-800-RECYCLE and requesting publications No. 92-45 and No. 90-22. Another unique recycling opportunity for businesses is available through the Industrial Materials Exchange. This free service acts as a waste or surplus “matchmaker,” helping one company’s waste become another company’s asset. For instance, waste vegetable oil can become biofuel for another business. Call Industrial Materials Exchange at (206) 625- 6232 to list potentially usable solid or chemical waste in their publication. BE AN ADVOCATE FOR STORMWATER POLLUTION PREVENTION Help friends, neighbors, and business associates find ways to reduce stormwater pollution in their activities. Most people want clean water and do not pollute intentionally. Share your ideas and the BMPs in this chapter to get them thinking about how their everyday activities effect water quality. REPORT PROBLEMS We all must do our part to protect water, fish, wildlife, and our own health by implementing proper BMPs, and reporting water quality problems that we observe. In the City of Yelm, call the Department of Public Works at (360) 458-8406 to report dumping to sewers and to report spills and other incidents involving storm drains or ditches. Also contact Ecology’s Southwest Regional Office at (360) 407-6300. PROVIDE OVERSIGHT AND TRAINING Assign one or more individuals at your place of business to be responsible for stormwater pollution control. Hold regular meetings to review the overall operation of BMPs. Establish TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 20 responsibilities for inspections, operation and maintenance (O&M), documentation, and availability for emergency situations. Train all team members in the operation, maintenance, and inspection of BMPs and reporting procedures. DUST CONTROL Sweep paved material handling and storage areas regularly as needed, to collect and dispose of dust and debris that could contaminate stormwater. Do not hose down pollutants from any area to the ground, storm drain, conveyance ditch, or receiving water. ELIMINATE ILLICIT CONNECTIONS An illicit connection is formally defined in the city’s NPDES Municipal Stormwater Permit, but generally includes any connection to the city stormwater system that is not intended, permitted, or used for collecting and conveying stormwater. A common problem with the stormwater drainage system for most communities is the existence of illicit connections of wastewater to the storm drainage system. Wastewater other than stormwater runoff, such as wash water, must be discharged to a wastewater collection system, and may not be discharged to a storm drainage system (the storm drainage system does not drain to a wastewater treatment plant). Many businesses and residences have internal building drains, sump overflows, process wastewater discharges, and even sanitary sewer and septic system pipes that were connected to the nearby storm drainage system in the past as a matter of course. All businesses and residences must examine their plumbing systems to determine if illicit connections exist. Any time it is found that toilets, sinks, appliances, showers and bathtubs, floor drains, industrial process waters, and/or other indoor activities are connected to the stormwater drainage system, these connections must be immediately rerouted to the sanitary or septic system, holding tanks, or a process treatment system. DISPOSE OF WASTE PROPERLY Every business and residence in the city must dispose of solid and liquid wastes and contaminated stormwater properly. There are generally four options for disposal depending on the type of materials. These options include: • Sanitary sewer and septic systems • Recycling facilities • Municipal solid waste disposal facilities • Hazardous waste treatment, storage, and disposal facilities TAHOMA TERRA RESIDENTIAL1B 09.23.2022 PAGE 21 Appendix A – Maintenance Checklists The Maintenance Checklists in this packet are for your use when inspecting the stormwater facilities on your property. This packet has been customized so that only the checklists for your facilities are included. If you feel you are missing a checklist, or you have additional facilities not identified or addressed in this packet, please contact your local jurisdiction. The checklists are in tabular format for ease of use. Each describes the area to inspect, inspection frequency, what to look for and what action to take. A log sheet is included after the appropriate maintenance checklists to help you track maintenance of your storm drainage system. Although it is not intended for the maintenance survey to involve anything too difficult or strenuous, there are a few tools that will make the job easier and safer including: • A flashlight • A long pole or broom handle • Some kind of pry bar or lifting tool for pulling manhole and grate covers • Gloves A resource list is included on page 11 of this Maintenance & Source Control Manual. There you will find the phone numbers of the agencies referenced in the tables, as well as the contractors and consultants who designed and constructed your facilities. SAFETY WARNING: In keeping with OSHA regulations, you should never stick your head or any part of your body into a manhole or other type of confined space. When looking into a manhole or catch basin, stand above it and use the flashlight to help you see. Use a long pole or broom handle to check sediment depths in confined spaces. NO PART OF YOUR BODY SHOULD BREAK THE PLANE OF THE OPEN HOLE.  ! December 2016 Volume V – Stormwater BMPs C-2 #1 – Maintenance Checklist for Detention Ponds: 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 Weeds 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 Thurston 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. Noxious and nuisance vegetation removed according to applicable regulations. (Coordinate with Thurston County.) Complete eradication of noxious weeds may not be possible. Compliance with state or local eradication policies required. General Contaminants and Pollution Any evidence of contaminants such as oil, gasoline, concrete slurries, or paint. No contaminants or pollutants present. (Coordinate source control, removal, and/or cleanup with Thurston County Water Resources 360-754-4681 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 Thurston County; 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 is 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 Tree Growth and Dense Vegetation Tree growth and dense vegetation 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. General Hazard Trees If dead, diseased, or dying trees are identified (Use a certified Arborist to determine health of tree or removal requirements). Hazard trees removed. General Performance Check crest gauge against design expectations (see Maintenance and Source Control Manual). 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. Repair/replace. December 2016 Volume V – Stormwater BMPs C-3 #1 – Maintenance Checklist for Detention Ponds: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed 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. Side Slopes of Pond 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. Storage Area Sediment Accumulated sediment that exceeds 10 percent of the designed pond depth unless otherwise specified or affects facility inlets or outlets. Sediment cleaned out to designed pond shape and depth; pond reseeded if necessary to control erosion. (If sediment contamination is a potential problem, sediment should be tested regularly to determine leaching potential prior to disposal.) Storage Area Liner (If Applicable) Liner is visible and has more than three one-fourth inch holes in it. Liner repaired or replaced. Liner is fully covered. Pond Berms (Dikes) Settlements Any part of berm which has settled 4 inches lower than the design elevation. 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 Over 4 ft in height (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. Pond Berms (Dikes) Piping Discernable water flow through pond berm. Ongoing erosion with potential for erosion to continue. Piping eliminated. Erosion potential eliminated.Recommend a geotechnical engineer be called in to inspect and evaluate condition and recommend repair of condition. 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 spillway 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. December 2016 Volume V – Stormwater BMPs C-4 #1 – Maintenance Checklist for Detention Ponds: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed 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 outflow 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. If you are unsure whether a problem exists, contact a professional engineer. December 2016 Volume V – Stormwater BMPs C-5 #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 Weeds 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 Thurston County Noxious Weeds List. (Apply requirements of adopted integrated pest management policies for the use f h bi id ) 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 Thurston County Water Resources 360-754-4681 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 Thurston County; 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. December 2016 Volume V – Stormwater BMPs C-6 #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 Well 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). December 2016 Volume V – Stormwater BMPs C-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 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. December 2016 Volume V – Stormwater BMPs C-9 #4 – Maintenance Checklist for Control Structure/Flow Restrictor: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Trash and Debris (Includes Sediment) Material exceeds 25 percent of sump depth or 1 foot below orifice plate. No trash and debris blocking or potentially blocking control structure orifice. General Structural Damage Structure is not securely attached to manhole wall. Structure securely attached to wall and outlet pipe. General Structural Damage Structure is not in upright position (allow up to 10 percent from plumb). Structure in correct position. General Structural Damage Connections to outlet pipe are not watertight and show signs of rust. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. General Structural Damage Any holes–other than designed holes–in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Cleanout Gate Damaged or Missing 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. Cleanout Gate Damaged or Missing Gate is rusted over 50 percent of its surface area. Gate is repaired or replaced to meet design standards. Orifice Plate Damaged or Missing Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Orifice Plate 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 overflow pipe. Pipe is free of all obstructions and works as designed. Manhole Cover Not in Place Cover is missing or only partially in place. Any open manhole requires maintenance. Manhole access cover/ lid is in place and secure. Manhole Locking Mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts into frame have less than one-half inch of thread (may not apply to self- locking lids). Mechanism opens with proper tools. Manhole Cover Difficult to Remove One maintenance person cannot remove lid after applying normal lifting pressure. Intent is to keep cover from sealing off access to maintenance. Cover can be removed and reinstalled by one maintenance person. Manhole 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 maintenance person safe access. If you are unsure whether a problem exists, contact a professional engineer. Control structures are usually considered a confined space. Visual inspections should be performed aboveground. If entry is required, it should be performed by qualified personnel. December 2016 Volume V – Stormwater BMPs C-10 #5 – Maintenance Checklist for Catch Basins: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General “Dump no pollutants” (or similar) stencil or stamp not visible Stencil or stamp should be visible and easily read. Warning signs (e.g., “Dump No Waste- Drains to Stream” or “Only rain down the drain”/ “Puget Sound starts here”) painted or embossed on or adjacent to all storm drain inlets. General Trash and Debris Trash or debris which is located immediately in front of the catch basin opening or is blocking inlet capacity by more than 10 percent. No trash or debris located immediately in front of catch basin or on grate opening. General Trash and Debris Trash or debris (in the basin) that exceeds 1/3 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 debris surface to the invert of the lowest pipe. No trash or debris in the catch basin. General Trash and Debris Trash or debris in any inlet or outlet pipe blocking more than one-third of its height. Inlet and outlet pipes free of trash or debris. General Trash and 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. General Sediment Sediment (in the basin) that exceeds 1/3 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. General Structure Damage to Frame and/or Top Slab Top slab has holes larger than 2 square inches or cracks wider than one-fourth inch. No holes and cracks in the top slab allowing material to run into the basin. General Structure Damage to Frame and/or Top Slab Frame not sitting flush on top slab, i.e., separation of more than three-fourth 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. General Fractures or Cracks in Basin Walls/ Bottom Maintenance person judges that structure is unsound. Basin replaced or repaired to design standards. General Fractures or Cracks in Basin Walls/ Bottom Grout fillet has separated or cracked wider than one-half-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. General Settlement/ Misalignment If failure of basin has created a safety, function, or design problem. Basin replaced or repaired to design standards. General Vegetation Vegetation growing across and blocking more than 10 percent of the basin opening. No vegetation blocking opening to basin. December 2016 Volume V – Stormwater BMPs C-11 #5 – Maintenance Checklist for Catch Basins: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Vegetation Vegetation growing in inlet/outlet pipe joints that is more than 6 inches tall and less than 6 inches apart. No vegetation or root growth present. General Contamination and Pollution Any evidence of oil, gasoline, contaminants or other pollutants. No contaminants or pollutants present. (Coordinate removal/cleanup with Thurston County Water Resources 360-754-4681 and/or Dept. of Ecology Spill Response 800- 424-8802.) 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 in place and secured. Catch Basin Cover Locking Mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts into frame have less than one-half- inch of thread. Mechanism opens with proper tools. Catch Basin Cover 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. Grates Grate Opening Unsafe Grate with opening wider than seven- eighths of an inch. Grate opening meets design standards. Grates Trash and Debris Trash and debris that is blocking more than 20 percent of grate surface inletting capacity. Grate free of trash and debris. Grates Damaged or Missing Grate missing or broken member(s) of the grate. Grateisinplaceandmeetsdesign standards. If you are unsure whether a problem exists, contact a professional engineer. December 2016 Volume V – Stormwater BMPs C-12 #6 – Maintenance Checklist for Debris Barriers (e.g., Trash Racks): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Trash and Debris Trash or debris that is plugging more than 20 percent of the openings in the barrier. Barrier cleared to receive design flow capacity. General Damaged/Missing Bars Bars are bent out of shape more than 3 inches. Bars in place with no bends more than three-fourth inch. General Damaged/Missing Bars Bars are missing or entire barrier missing. Bars in place according to design. General Damaged/Missing Bars Bars are loose and rust is causing 50 percent deterioration to any part of barrier. Barrier replaced or repaired to design standards. General Inlet/Outlet Pipe Debris barrier missing or not attached to pipe. Barrier firmly attached to pipe. If you are unsure whether a problem exists, contact a professional engineer. December 2016 Volume V – Stormwater BMPs C-13 #7 – Maintenance Checklist for Energy Dissipaters: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed External: Rock Pad Missing or Moved Rock Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil. Rock pad replaced to design standards. Rock Pad Erosion Soil erosion in or adjacent to rock pad. Rock pad replaced to design standards. Dispersion Trench Pipe Plugged with Sediment Accumulated sediment that exceeds 20 percent of the design depth. Pipe cleaned/flushed so that it matches design. Dispersion Trench Not Discharging Water Properly Visual evidence of water discharging at concentrated points along trench (normal condition is a “sheet flow” of water along trench). Intent is to prevent erosion damage. Water discharges from feature by sheet flow. Trench redesigned or rebuilt to standards. Dispersion Trench Perforations Plugged Over one-half of perforations in pipe are plugged with debris and sediment. Perforations freely discharge flow. Perforated pipe cleaned or replaced. Dispersion Trench Water Flows Out Top of “Distributor” Catch Basin Water flows out of distributor catch basin during any storm less than the design storm or is causing or appears likely to cause damage. No flow discharges from distributor catch basin. Facility rebuilt or redesigned to standards. Dispersion Trench Receiving Area Over-Saturated Water in receiving area is causing or has potential of causing landslide problems. No danger of landslides. Internal: Manhole/ Chamber Worn or Damaged Post, Baffles, Side of Chamber Structure dissipating flow deteriorates to one-half of original size or any concentrated worn spot exceeding 1 square foot which would make structure unsound. Structure in no danger of failing. Structure replaced to design standards if needed. Manhole/ Chamber Trash and Debris Trash or debris (in the basin) that exceeds 1/3 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 debris surface to the invert of the lowest pipe. No trash or debris in the catch basin. Manhole/ Chamber Trash and Debris Trash or debris in any inlet or outlet pipe blocking more than one-third of its height. Inlet and outlet pipes free of trash or debris. Manhole/ Chamber Trash and 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. Manhole/ Chamber 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. December 2016 Volume V – Stormwater BMPs C-14 #7 – Maintenance Checklist for Energy Dissipaters: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Manhole/ Chamber Structure Damage to Frame and/or Top Slab Top slab has holes larger than 2 square inches or cracks wider than one-fourth inch. No holes and cracks in top slab allowing material to run into the basin. Manhole/ Chamber Structure Damage to Frame and/or Top Slab Frame not sitting flush on top slab, i.e., separation of more than three-fourth 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. Manhole/ Chamber Fractures or Cracks in Basin Walls/ Bottom Maintenance person judges that structure is unsound. Basin replaced or repaired to design standards. Manhole/ Chamber Fractures or Cracks in Basin Walls/ Bottom Grout fillet has separated or cracked wider than one-half-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. Manhole/ Chamber Settlement/ Misalignment If failure of basin has created a safety, function, or design problem. Basin replaced or repaired to design standards. Manhole/ Chamber Contamination and Pollution Any evidence of oil, gasoline, contaminants or other pollutants. No contaminants or pollutants present. (Coordinate removal/cleanup with Thurston County Water Resources 360-754-4681 and/or Dept. of Ecology Spill Response 800- 424-8802.) 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. Catch Basin Cover Locking Mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts into frame have less than one-half- inch of thread. Mechanism opens with proper tools. Catch Basin Cover 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. If you are unsure whether a problem exists, contact a professional engineer. December 2016 Volume V – Stormwater BMPs C-19 #11 – Maintenance Checklist for Wet Ponds: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Water level First cell is empty, does not hold water. Water retained in first cell for most of the year. Line the first cell to maintain at least 4 feet of water. Although the second cell may drain, the first cell must remain full to control turbulence of the incoming flow and reduce sediment resuspension. Trash and Debris Accumulation that exceeds one cubic foot per 1,000 square feet of pond area. No trash or debris on site. Any trash and debris removed from pond. Inlet/Outlet Pipe Inlet/Outlet pipe clogged with sediment and/or debris material. No clogging or blockage in the inlet and outlet piping. Sediment Accumulation in Pond Bottom Sediment accumulations in pond bottom that exceeds the depth of sediment zone plus 6 inches, usually in the first cell. Sediment removed from pond bottom. (If sediment contamination is a potential problem, sediment should be tested regularly to determine leaching potential prior to disposal.) Oil Sheen on Water Prevalent and visible oil sheen. Oil removed from water using oil- absorbent pads or vactor truck. Source of oil located and corrected. If chronic low levels of oil persist, plant wetland plants such as Juncus effusus (soft rush) which can uptake small concentrations of oil. Erosion Erosion of the pond’s side slopes and/or scouring of the pond bottom that exceeds 6 inches, or where continued erosion is prevalent. Slopes stabilized using proper erosion control measures and repair methods. Settlement of Pond Dike/Berm Any part of these components that has settled 4 inches or lower than the design elevation, or inspector determines dike/berm is unsound. Dike/berm is repaired to specifications. Internal Berm Berm dividing cells should be level. Berm surface is leveled so that water flows evenly over entire length of berm. Overflow Spillway Rock is missing and soil is exposed at top of spillway or outside slope. Rocks replaced to specifications. If you are unsure whether a problem exists, contact a professional engineer. December 2016 Volume V – Stormwater BMPs C-31 #19 – Maintenance Checklist for Fencing/Shrubbery Screen/Other Landscaping: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Missing or Broken Parts/Dead Shrubbery Any defect in the fence or screen that permits easy entry to a facility. Fence is mended or shrubs replaced to form a solid barrier to entry. General Erosion Erosion has resulted in an opening under a fence that allows entry by people or pets. Soil under fence replaced so that no opening exceeds 4 inches in height. General Unruly Vegetation Shrubbery is growing out of control or is infested with weeds. See also Thurston County Noxious weeds list. Shrubbery is trimmed and weeded to provide appealing aesthetics. Do not use chemicals to control weeds. Fences Damaged Parts Posts out of plumb more than 6 inches. Posts plumb to within 1.5 inches of plumb. Fences Damaged Parts Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Fences Damaged Parts Any part of fence (including posts, top rails, and fabric) more than 1 foot out of design alignment. Fence is aligned and meets design standards. Fences Damaged Parts Missing or loose tension wire. Tension wire in place and holding fabric. Fences Damaged Parts Missing or loose barbed wire that is sagging more than 2.5 inches between posts. Barbed wire in place with less than three-fourth inch sag between posts. Fences Damaged Parts Extension arm missing, broken, or bent out of shape more than 1.5 inches. Extension arm in place with no bends larger than three-fourth inch. Fences Deteriorated Paint or Protective Coating Part or parts that have a rusting or scaling condition that has affected structural adequacy. Structurally adequate posts or parts with a uniform protective coating. Fences Openings in Fabric Openings in fabric are such that an 8- inch diameter ball could fit through. No openings in fabric. December 2016 Volume V – Stormwater BMPs C-34 #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. December 2016 Volume V – Stormwater BMPs C-43 #29 – Maintenance Checklist for Bioretention (Cells, Swales, and Planter Boxes): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed General Trash Trash and debris present. No trash and debris present. Concrete Sidewalls Cracks or Failure in Concrete Planter Reservoir Cracks wider than 0.5 inch or maintenance/inspection personnel determine that the planter is not structurally sound. Concrete repaired or replaced. Rockery Sidewalls Instable Rockery Rock walls are insecure. Rockery sidewalls are stable (may require consultation with professional engineer, particularly for walls 4 feet or greater in height). Earthen Side Slopes and Berms Failure in Earthen Reservoir (Embankments, Dikes, Berms, and Side Slopes) Erosion (gullies/rills) greater than 2 inches around inlets, outlet, and along side slopes. Source of erosion eliminated and damaged area stabilized (regrade, rock, vegetation, erosion control blanket). For deep channels or cuts (over 3 inches in ponding depth), temporary erosion control measures are in place until permanent repairs can be made. Earthen Side Slopes and Berms Failure in Earthen Reservoir (Embankments, Dikes, Berms, and Side Slopes) Erosion of sides causes slope to become a hazard. The hazard is eliminated and slopes are stabilized. Earthen Side Slopes and Berms Failure in Earthen Reservoir Embankments, Dikes, Berms, and Side Slopes) Settlement greater than 3 inches (relative to undisturbed sections of berm). The design height is restored with additional mulch. Earthen Side Slopes and Berms Failure in Earthen Reservoir (Embankments, Dikes, Berms, and Side Slopes) Downstream face of berm or embankment wet, seeps or leaks evident. Holes are plugged and berm is compacted. May require consultation with professional engineer, particularly for larger berms. Earthen Side Slopes and Berms Failure in Earthen Reservoir (Embankments, Dikes, Berms, and Side Slopes) Any evidence of rodent holes or water piping around holes if facility acts as dam or berm. Rodents (see “Pests: Insects/Rodents”) removed or destroyed and berm repaired/ compacted. Ponding Area Sediment or Debris Accumulation Accumulation of sediment or debris to extent that infiltration rate is reduced (see “Ponded water”) or surface storage capacity significantly impacted. Sediment cleaned out to restore facility shape and depth. Damaged vegetation is replaced and mulched. Source of sediment identified and controlled (if feasible). Ponding Area Leaf Accumulation Accumulated leaves in facility. No leaves clogging outlet structure or impeding water flow. Ponding Area Basin Inlet via Surface Flow Soil is exposed or signs of erosion are visible. Erosion sources repaired and controlled. Curb Cut Inlet Sediment or Debris Accumulation Sediment, vegetation, or debris partially or fully blocking inlet structure. Curb cut is clear of debris. Source of the blockage is identified and action is taken to prevent future blockages. December 2016 Volume V – Stormwater BMPs C-44 #29 – Maintenance Checklist for Bioretention (Cells, Swales, and Planter Boxes): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Splash Block Inlet Water Not Properly Directed to Facility Water is not being directed properly to the facility and away from the inlet structure. Blocks are reconfigured to direct water to facility and away from structure. Splash Block Inlet Erosion Water disrupts soil media. Splash block is reconfigure/repaired. Inlet/outlet pipe Damaged Pipe Pipe is damaged. Pipe is repaired/replaced. No cracks more than 0.25 inched wide at the joint of inlet/outlet pipes exist. Inlet/outlet pipe Clogged Pipe Pipe is clogged. Pipe is clear of roots or debris. Source of the blockage is identified and action is taken to prevent future blockages. Inlets/outlet and access pathways Blocked Access Maintain access for inspections. Vegetation is cleared within 1 foot of inlets and outlets. Access pathways are maintained. Ponding Area Erosion Water disrupts soil media. No eroded or scoured areas in bioretention area. Cause of erosion or scour addressed. A cover of rock or cobbles or other erosion protection measure maintained (e.g., matting) to protect the ground where concentrated water enters or exits the facility (e.g., a pipe, curb cut or swale). Trash Rack Trash or Debris Accumulation Trash or debris present on trash rack. No trash or debris on trash rack. Clean and dispose trash. Trash Rack Damaged Trash Rack Bar screen damaged or missing. Barrier repaired or replaced to design standards. Check Dams and Weirs Sediment or Debris Accumulation Sediment, vegetation, or debris accumulated at or blocking (or having the potential to block) check dam, weir, or orifice. Blockage is cleared. Identify the source of the blockage and take actions to prevent future blockages. Check Dams and Weirs Erosion Erosion and/or undercutting is present. No eroded or undercut areas in bioretention area. Cause of erosion or undercutting addressed. Check dam or weir is repaired. Check Dams and Weirs Unlevel Top of Weir Grade board or top of weir damaged or not level. Weir restored to level position. Flow Spreader Sediment Accumulation Sediment blocks 35 percent or more of ports/notches or, sediment fills 35 percent or more of sediment trap. Sediment removed and disposed of. Flow Spreader Damaged or Unlevel Grade Board/Baffle Grade board/baffle damaged or not level. Board/baffle removed and reinstalled to level position. Overflow/ emergency spillway Sediment or Debris Accumulation Overflow spillway is partially or fully plugged with sediment or debris. No sediment or debris in overflow. Overflow/ emergency spillway Erosion Native soil is exposed or other signs of erosion damage are present. Erosion repaired and surface of spillway stabilized. December 2016 Volume V – Stormwater BMPs C-45 #29 – Maintenance Checklist for Bioretention (Cells, Swales, and Planter Boxes): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Overflow/ emergency spillway Missing Spillway Armament Spillway armament is missing. Armament replaced. Underdrain Blocked Underdrain Plant roots, sediment or debris reducing capacity of underdrain. Prolonged surface ponding (see “Bioretention Soil”). Underdrains and orifice are free of sediment and debris. Bioretention soil Ponded Water Excessive ponding water: Water overflows during storms smaller than the design event or ponded water remains in the basin 48 hours or longer after the end of a storm. Cause of ponded water is identified and addressed: 1. Leaf or debris buildup is removed 2. Underdrain is clear 3. Other water inputs (e.g., groundwater, illicit connections) investigated 4. Contributing area verified If steps #1-4 do not solve the problem, imported bioretention soil is replaced and replanted. Bioretention soil Protection of Soil Maintenance requiring entrance into the facility footprint. Maintenance is performed without compacting bioretention soil media. Vegetation Bottom Swale and Upland Slope Vegetation Less than 75 percent of swale bottom is covered with healthy/ surviving vegetation. Plants are healthy and pest free. Cause of poor vegetation growth addressed. Bioretention area is replanted as necessary to obtain 75 percent survival rate or greater. Plant selection is appropriate for site growing conditions. Trees and shrubs Causing Problems for Operation of Facility Large trees and shrubs interfere with operation of the basin or access for maintenance. Trees and shrubs do not hinder facility performance or maintenance activities. Prune or remove large trees and shrubs. Trees and shrubs Dead Trees and Shrubs Standing dead vegetation is present. Trees and shrubs do not hinder facility performance or maintenance activities. Dead vegetation is removed and cause of dead vegetation is addressed. Specific plants with high mortality rate are replaced with more appropriate species. Trees and shrubs adjacent to vehicle travel areas (or areas where visibility needs to be maintained) Safety Issues Vegetation causes some visibility (line of sight) or driver safety issues. Appropriate height for sight clearance is maintained. Regular pruning maintains visual sight lines for safety or clearance along a walk or drive. Tree or shrub is removed or transplanted if presenting a continual safety hazard. Emergent Vegetation Conveyance Blocked Vegetation compromises conveyance. Sedges and rushes are clear of dead foliage. Mulch Lack of Mulch Bare spots (without much cover) are present or mulch covers less than 2 inches. Facility has a maximum 3-inch layer of an appropriate type of mulch and mulch is kept away from woody stems. Vegetation Accumulation of Clippings Grass or other vegetation clippings accumulate to 2 inches or greater in depth. Clippings removed. December 2016 Volume V – Stormwater BMPs C-46 #29 – Maintenance Checklist for Bioretention (Cells, Swales, and Planter Boxes): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Noxious Weeds Presence of Noxious Weeds Listed noxious vegetation is present. See Thurston County noxious weed list. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County personnel or the public might normally be. It is strongly encouraged that herbicides and pesticides not be used in order to protect water quality. Vegetation Weeds Weeds are present (unless on edge and providing erosion control). Weed material removed and disposed of. It is strongly encouraged that herbicides and pesticides not be used in order to protect water quality. Excessive Vegetation Adjacent Facilities Compromised Low-lying vegetation growing beyond facility edge onto sidewalks, paths, or street edge poses pedestrian safety hazard or may clog adjacent permeable pavement surfaces due to associated leaf litter, mulch, and soil. Vegetation does not impede function of adjacent facilities or pose as safety hazard. Groundcovers and shrubs trimmed at facility edge. Excessive leaf litter is removed. Excessive Vegetation Causes Facility to Not Function Properly Excessive vegetation density inhibits stormwater flow beyond design ponding or becomes a hazard for pedestrian and vehicular circulation and safety. Pruning and/or thinning vegetation maintains proper plant density and aesthetics. Plants that are weak, broken, or not true to form are removed or replaced in-kind. Appropriate plants are present. Irrigation (if any) NA Irrigation system present. Manufacturer’s instructions for O&M are met. Plant watering Plant Establishment Plant establishment period (1-3 years). Plants are watered as necessary during periods of no rain to ensure plant establishment. Summer Watering (after establishment) Drought Period Longer term period (3+ years). Plants are watered as necessary during drought conditions and trees are watered up to five years after planting. Spill Prevention and Response Spill Prevention Storage or use of potential contaminants in the vicinity of facility. Spill prevention measures are implemented whenever handling or storing potential contaminants. Spill Prevention and Response Spill Response Any evidence of contaminants such as oil, gasoline, concrete slurries, paint, etc. Spills are cleaned up as soon as possible to prevent contamination of stormwater. No contaminants or pollutants present. (Coordinate source control, removal, and/or cleanup with Thurston County Water Resources 360-754-4681 and/or Dept. of Ecology Spill Response 800- 424-8802.) Safety Safety (Slopes) Erosion of sides causes slope to exceed 1:3 or otherwise becomes a hazard. Actions taken to eliminate the hazard. Safety Safety (Hydraulic Structures) Hydraulic structures (pipes, culverts, vaults, etc.) become a hazard to children playing in and around the facility. Actions taken to eliminate the hazard (such as covering and securing any openings). December 2016 Volume V – Stormwater BMPs C-47 #29 – Maintenance Checklist for Bioretention (Cells, Swales, and Planter Boxes): Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Aesthetics Aesthetics Damage/vandalism/debris accumulation. Facility restored to original aesthetic conditions. Aesthetics Edging Grass is starting to encroach on swale. Edging repaired. Pest Control Pests: Insects/Rodents Pest of concern is present and impacting facility function. Pests removed or destroyed and facility returned to original functionality. Do not use pesticides or Bacillus thuringiensis israelensis (Bti). Pest Control Mosquitoes Standing water remains in the basin for more than three days following storms. All inlets, overflows and other openings are protected with mosquito screens. No mosquito infestation present. If you are unsure whether a problem exists, contact a professional engineer. December 2016 Volume V – Stormwater BMPs C-55 #33 – Maintenance Checklist for Downspout, Sheet Flow, and Concentrated Dispersion Systems: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Splash block Water Directed Toward Building Water is being directed towards building structure. Water directed away from building structure. Splash block Water Causing Erosion Water disrupts soil media. Blocks are reconfigured/ repaired and media is restored. Transition zone Erosion Adjacent soil erosion; uneven surface creating concentrated flow discharge; or less than 2 foot of width. No eroded or scoured areas. Cause of erosion or scour is addressed. Dispersion trench Concentrated Flow Visual evidence of water discharging at concentrated points along trench (normal condition is a “sheet flow” from edge of trench; intent is to prevent erosion damage). No debris on trench surface. Notched grade board or other distributor type is aligned to prevent erosion. Trench is rebuilt to standards, if necessary. Surface of trench Accumulated Debris Accumulated trash, debris, or sediment on drain rock surface impedes sheet flow from facility. Trash or debris is removed/disposed in accordance with local solid waste requirements. Surface of trench Vegetation Impeding Flow Vegetation/moss present on drain rock surface impedes sheet flow from facility. Freely draining drain rock surface. Pipe(s) to trench Accumulated Debris in Drains Accumulation of trash, debris, or sediment in roof drains, gutters, driveway drains, area drains, etc. No trash or debris in roof drains, gutters, driveway drains, or area drains. Pipe(s) to trench Accumulated Debris in Inlet Pipe Pipe from sump to trench or drywell has accumulated sediment or is plugged. No sediment or debris in inlet/outlet pipe screen or inlet/outlet pipe. Pipe(s) to trench Damaged Pipes Cracked, collapsed, broken, or misaligned drain pipes. No cracks more than 0.25-inch wide at the joint of the inlet/outlet pipe. Sump Accumulated Sediment Sediment in the sump. Sump contains no sediment. Access lid Hard to Open Cannot be easily opened. Access lid is repaired or replaced. Access lid Buried Buried. Access lid functions as designed (refer to record drawings for design intent). Access lid Missing Cover Cover missing. Cover is replaced. Rock pad Inadequate Rock Cover Only one layer of rock exists above native soil in area 6 square feet or larger, or any exposure of native soil. Rock pad is repaired/replaced to meet design standards. Rock pad Erosion Soil erosion in or adjacent to rock pad. Rock pad is repaired/replaced to meet design standards. Dispersal Area Erosion Erosion (gullies/ rills) greater than 2 inches deep in dispersal area. No eroded or scoured areas. Cause of erosion or scour is addressed. Dispersal Area Accumulated Sediment Accumulated sediment or debris to extent that blocks or channelizes flow path. No excess sediment or debris in dispersal area. Sediment source is addressed (if feasible). December 2016 Volume V – Stormwater BMPs C-56 #33 – Maintenance Checklist for Downspout, Sheet Flow, and Concentrated Dispersion Systems: Drainage System Feature Defect or Problem Condition When Maintenance Is Needed Results Expected When Maintenance Is Performed Ponded water Ponded Water Standing surface water in dispersion area remains for more than 3 days after the end of a storm event. System freely drains and there is no standing water in dispersion area between storms. The cause of the standing water (e.g., grade depressions, compacted soil) is addressed. Vegetation Plant Survival Dispersal area vegetation in establishment period (1-2 years, or additional 3rd year) during extreme dry weather). Vegetation is healthy and watered weekly during periods of no rain to ensure plant establishment. Vegetation Lack of Vegetation Allowing Erosion Poor vegetation cover such that erosion is occurring. Vegetation is healthy and watered. No eroded or scoured areas are present. Cause of erosion or scour is addressed. Plant species are appropriate for the soil and moisture conditions. Vegetation Vegetation Blocking Flow Vegetation inhibits dispersed flow along flow path. Vegetation is trimmed, weeded, or replanted to restore dispersed flow path. Vegetation Presence of Noxious Weeds Any noxious or nuisance vegetation which may constitute a hazard to county personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where county personnel or the public might normally be. Pest Control Mosquito Infestation Standing water remains for more than three days following storms. All inlets, overflows and other openings are protected with mosquito screens. No mosquito infestation present. Rodents Presence of Rodents Rodent holes or mounds disturb dispersion flow paths. Rodents removed or destroyed, holes are filled, and flow path is revegetated. If you are unsure whether a problem exists, contact a professional engineer. TAHOMA TERRA RESIDENTIAL RESIDENTIAL1B 10.07.2022 PAGE 21 Log Sheet Use log sheets to track maintenance checks and what items, if any, are repaired or altered. Make copies of this page; use a fresh copy for each inspection. The completed sheets will serve as a record of maintenance activity and will provide valuable information about how your facilities are operating. Log sheets should be kept in a dry, readily accessible place. INSPECTION DATE: PERFORMED BY: PHONE NUMBER: ADDRESS: POSITION ON HOA: CITY, ST, ZIP: PART OF FACILITY INSPECTED OBSERVATIONS (LIST REQUIRED MAINTENANCE ACTIVITIES) ACTION TAKEN DATE OF ACTION