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Home My WebLink AboutBLD2021-00452-05- Stormwater or Approved StormwaterAug 10 2021 Aug 10 2021 Aug 10 2021 Start HERE! A guide to using stormwater forms Use the quantities reported in this worksheet to determine which minimum requirements apply to your project and what forms will be required using the “Flow Chart for Determining Minimum Requirements.” Step 1 Yes no All projects must read and complete the Stormwater Calculation Worksheet. Small Projects may submit the Worksheet S Small Project Certification sheet. Applicants who are able to sign the certification may STOP HERE. Submit the Stormwater Calculation Worksheet and Worksheet “S” with your appli- cation. No additional submittal is necessary. Step 2 Step 2.1 Step 2.1 Medium Projects must complete worksheets A1, B1, and C or equivalent. Large Projects refer to Worksheet L to determine applicable worksheets are required or if a state -licensed engineer must prepare the submittal. A Note on Engineered Stormwater Submittal: -Many applicants complete stormwater submittal forms independently without professional expertise. For example, full dispersion, if feasible on the site (See Worksheet C), is typically easiest to implement for many different surface types suc h as roof, driveway, patio etc. -Applicants may opt to submit an engineered stormwater plan even if it isn’t required. This option may be attractive to those who are unsure how some of the requirements will be achieved on the site.In some instances, engineering will be required. Certain Large projects must be engineered (See Worksheet L). Gathering information on infiltration feasibility may need an engineer ’s expertise. Or, sites with greater than 15% slopes may require applicants hire a geologist to recommend if a drainage method i s appropriate. Discharging directly to a marine water via tightline must be engineered. If you cannot do full dispersion on par cels larger than 5 acres, engineering is required. In other instances, site constraints will require an engineered design. -Jefferson County staff may assist by providing and/or explaining Department of Ecology Stormwater Management Manual The project requires or the applicant elects to submit an engineered stormwater plan. The plan is attached hereto with minimum requirement narrative, drawings, calculation, modeling output, construction pollution prevention plan, and site plan. Circle one: Step 3 If you answered YES above, STOP, no further submittal is required. Otherwise, proceed with the following steps. Complete Worksheet A1 Medium/Large Project Report and Stormwater Site Plan or equivalent. Step 3.1 Complete Worksheet C to determine which BMPs are possible and appropriate for your site. Circle the first BMP that is feasible (i.e. none of the infeasibility criteria is checked) for each surface type. Circle the corresponding BMP on Worksheet A1. Step 4 Complete Worksheet B1 Medium/Large Project Construction Pollution Prevention Plan and Worksheet B2 Construction Site Plan or equivalent. A Note on Commercial Projects: • Jefferson County Public Works (JCPW) reviews commercial projects and charges a review fee. JCPW may charge additional fees for any required inspections. • Any commercial projects proposing infiltration facilities may complete Worksheet E —Infiltration Test. Grain size analysis may be used instead of PIT. Commercial projects may elect to use BMP T5.10A and would not need a PIT, just a soil evaluation. • Any development for cottage industries may require a commercial public works review if full dispersion is infeasible. 5IJTJTBMBSHFQSPKFDU -BSHFQSPKFDUTSFGFSUP 8PSLTIFFU-GPSTVCNJUUBM SFRVJSFNFOUT"UB NJOJNVN BMMMBSHF1SPKFDU NVTUTVCNJU8PSLTIFFU " # BOE$PS FRVJWBMFOU 5IJTJTBNFEJVN QSPKFDU4VCNJU 8PSLTIFFU" # BOE$PS FRVJWBMFOU $PNQMFUF4NBMM1SPKFDU$FSUJGJDBUJPO8PSLTIFFU 1SPKFDUNVTUGPMMPX$POTUSVDUJPO1PMMVUJPO1SFWFOUJPO'BDU4IFFU 'JHVSF'MPX$IBSUGPS/FX%FWFMPQNFOU 5IJTJTBMBSHFQSPKFDU-BSHFQSPKFDUTSFGFSUP8PSLTIFFU-GPS TVCNJUUBMSFRVJSFNFOUT"UBNJOJNVN BMMMBSHF1SPKFDUNVTUTVCNJU 8PSLTIFFU" # BOE$PSFRVJWBMFOU 'JHVSF'MPX$IBSUGPS3FEFWFMPQNFOU construction Pollution Prevention Page 1 of 3 5/31/2019 DEPARTMENT OF COMMUNITY DEVELOPMENT 621 Sheridan Street, Port Townsend, WA 98368 Tel: 360.379.4450 | Fax: 360.379.4451 Web: www.co.jefferson.wa.us/communitydevelopment E-mail: dcd@co.jefferson.wa.us CONSTRUCTION STORMWATER POLLUTION PREVENTION Best Management Practices (BMPs) Fact Sheet For “small” projects (as determined through the Stormwater Calculation Worksheet), submit Worksheet “S” Small Project Certification. Additionally, the applicant shall consider the twelve Construction Stormwater Pollution Prevention elements and implement applicable BMPs. A set of useful BMPs for typical rural residential construction is attached. There is no additional submittal required as part of the permit application. For “medium” and “large” projects, applicants must submit a Construction Stormwater Pollution Prevention Plan (SWPPP) and a Stormwater Site Plan (applicants may use Worksheet B1 or equivalent). The following twelve elements must be considered for Construction Stormwater Pollution Prevention before and during the construction phase of the project: 1. Mark Clearing Limits 7. Protect Drain Inlets 2. Establish Construction Access 8. Stabilize Channels and Outlets 3. Control Flow Rates 9. Control Pollutants 4. Install Sediment Controls 10. Control De-Watering 5. Stabilize Soils 11. Maintain Best Management Practices 6. Protect Slopes 12. Manage The Project Each of the twelve elements is described in more detail below: 1. Mark Clearing Limits By minimizing the limits of clearing on the site, a builder can minimize stormwater runoff and provide effective control of pollution. 2. Establish Construction Access Much of the sediment that leaves a construction site does so on the wheels of delivery and construction vehicles that drive off a project site. Construction access must be limited to a single location and a properly constructed Stabilized Construction Entrance (BMP C105) should be included on the site. 3. Control Flow Rates Stormwater that leaves a project site unimpeded may exceed the capacity of the existing stormwater control facilities downstream and may contain sediment that may be deposited as the velocity of the runoff decreases. Stormwater protection on a construction site should include measures to control the flow rate of runoff from the site. This can be done by installing a Sediment Trap (BMP C240) or other measure that will impede the flow of water off a construction site. 4. Install Sediment Controls In addition to limiting the rate of stormwater flow off a construction site, measures should be put in place to treat the runoff and remove sediment. Limiting of the cleared area (Element 1) will assist in this effort, but there will be exposed soils that may move with the runoff. Suggested BMPs for controlling sediment include Straw Wattles (BMPC235), Brush Barrier (BMP C231), Gravel Filter Berm (BMP C232), and Silt Fence (BMP C233). Installation of a Sediment Trap (Element 3) is an additional sediment control feature. construction Pollution Prevention Page 2 of 3 5/31/2019 5. Stabilize Soils An additional measure that can minimize sediment transport in runoff is to stabilize soils on the site with mulch or some other covering. This will limit the amount of soil that is exposed to rainfall, thus limiting the sediment that could potentially leave the site. BMPs that could be used for this include Mulching (BMP C121), Nets and Blankets (BMP C122), and Plastic Covering (BMP C123). During periods of dry weather dust can become a problem and sediment could be transported from the site in high winds. BMP C140 Dust Control should be followed to limit loss of soils in windy conditions. 6. Protect Slopes If the cleared area includes slopes of 3:1 (Horizontal: Vertical) or steeper, the slopes should be protected to limit runoff. If the slopes are not protected, rills and gullies may form, transporting sediment to the lower elevations and potentially off the construction site. The slopes sh ould be graded to minimize erosion and runoff at the downstream end of the slopes, and runoff should be collected and treated. The following BMPs could be used Surface Roughening (BMP C130), Interceptor Dike and Swale (BMP C200), and Pipe Slope Drains (BMP C204). 7. Protect Drain Inlets Runoff from urban construction sites often discharges into existing stormwater collection systems. Water enters the collection system through drain inlets. If there are drain inlets downstream of a construction site, they should be protected using BMP C220 Storm Drain Inlet Protection. 8. Stabilize Channels and Outlets Any temporary on-site channels or ditches that are used to control runoff should be stabilized to prevent erosion in the channel. BMP C202 Channel Lining and BMP C209 Outlet Protection should be used. 9. Control Pollutants The best way to control pollution is to limit the source of pollution. Construction debris should be maintained in a safe location. Vehicle maintenance on the construction site should be minimized and any spill should be promptly cleaned up. Concrete spillage should be kept to a minimum and cleaning of the concrete trucks after they have unloaded should be done in an area that will not drain off site (see BMP C151 Concrete Handling). 10. Control Dewatering In some cases, excavation for the foundation or below ground structures will encounter ground water. This water must be removed (dewatered) from the excavation. Discharge of this ground water must be treated in a manner that will not cause damage downstream due to flow rates or added pollution. There are no specific BMP identified for this activity, but the water should be handled with care to assure that soils or other pollutants are not added to this flow. 11. Maintain BMPs Installation of the appropriate BMPs is not adequate to completely control stormwater runoff. The BMPs that have been installed on the project must be inspected and maintained during the duration of the construction project. In addition, the temporary controls that were installed for construction should be removed within 30 days of completion of the work. Typically, once construction has been completed, the temporary facilities are not maintained, and by removing the facilities, it will ensure that these won’t f ail and discharge water or sediment that had been previously trapped or contained. 12. Manage the Project Management of a project has four aspects: 1. Phasing construction to prevent transportation of runoff and sediment, 2. Limiting the work during seasons where large amounts of rainfall could be anticipated, 3. Coordination with Utilities and other Contractors, and 4. Inspection and Monitoring. All of these for aspects are important and must be followed to ensure a project that will have minimal impact on the environment. Volume II of the Manual contains additional BMPs that could be used on-site. The applicant is encouraged to review the Manual to see if other BMPs may be applicable to, or more useful on, a particular site. construction Pollution Prevention Page 3 of 3 5/31/2019 Best Management Practices from 2014 Ecology Stormwater Management Manual The following BMPs for Construction Stormwater Pollution Prevention are sediment and erosion control measures for the construction phase of typical rural residential development. Some projects may not require implementation of all of these BMPs; others may require additional measures not listed here. Click on the BMP to learn more about each BMP’s purpose and design: II-4.1 Source Control BMPs BMP C101: Preserving Natural Vegetation BMP C102: Buffer Zones BMP C103: High Visibility Fence BMP C105: Stabilized Construction Entrance / Exit BMP C106: Wheel Wash BMP C107: Construction Road/Parking Area Stabilization BMP C120: Temporary and Permanent Seeding BMP C121: Mulching BMP C122: Nets and Blankets BMP C123: Plastic Covering BMP C124: Sodding BMP C125: Topsoiling / Composting BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection BMP C130: Surface Roughening BMP C131: Gradient Terraces BMP C140: Dust Control BMP C150: Materials on Hand BMP C151: Concrete Handling BMP C152: Sawcutting and Surfacing Pollution Prevention BMP C153: Material Delivery, Storage and Containment BMP C154: Concrete Washout Area BMP C160: Certified Erosion and Sediment Control Lead BMP C162: Scheduling II-4.2 Runoff Conveyance and Treatment BMPs BMP C200: Interceptor Dike and Swale BMP C201: Grass-Lined Channels BMP C202: Channel Lining BMP C203: Water Bars BMP C204: Pipe Slope Drains BMP C205: Subsurface Drains BMP C206: Level Spreader BMP C207: Check Dams BMP C208: Triangular Silt Dike (TSD) (Geotextile-Encased Check Dam) BMP C209: Outlet Protection BMP C220: Storm Drain Inlet Protection BMP C231: Brush Barrier BMP C232: Gravel Filter Berm BMP C233: Silt Fence BMP C234: Vegetated Strip BMP C235: Wattles BMP C236: Vegetative Filtration BMP C240: Sediment Trap BMP C241: Temporary Sediment Pond BMP C251: Construction Stormwater Filtration