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HomeMy WebLinkAbout05- Stormwater Revised Whipple Stormwater WorksheetsSON Start HERE! A guide to using stormwater forms Step 1 All projects must read and complete the stormwater Calculation Worksheet, Step 2 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 2,1 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 2.1 Medium Projects must complete worksheets Al, 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 such 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 Q. 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 is appropriate. Discharging directly to a marine water via tightline must be engineered. If you cannot do full dispersion on parcels 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 Circle one: 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 Yes no plan, and site plan. If you answered YES above, STOP, no further submittal is required. Otherwise, proceed with the following steps. Step 3 Complete Worksheet Al Medium/Large Project Report and Stormwater Site Plan or equivalent. Step 3.1 Complete Worksheet C to determine which SMPs 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 Al. 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 TS.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. STORMWATER CALCULATIONS - IMPERVIOUS SURFACE impervious surface is a hard surface that either prevents or slows the entry of water into the soil as under natural conditions prior to development. A hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include, but are not limited to roof tops, walkways, patios, driveways, parking lots or storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled, macadam or other surfaces which similarly impede the natural infiltration of stormwater. NEW Structures (all roof area) o,549 sg/ft Sidewalks Patios Solid Decks (without infiltration below) Driveway, parking, roads, Other sq/ft sq/ft sq/ft etc sq/ff sglft Total New I 8 `C sglft TOTAL NEW + TOTAL EXISTING* 1 q V 2' r sglft EXISTING Structures (all roof area) Sidewalks Patios Solid Decks (without infiltration below) 1 aD sglft sq/ft sq/ft Driveway, parking, roads, etc I, toO sq/ft Other sq/ft Total Existing 12 9 SD sglfi *This amount will be used to check total lot coverage. DEVELOPMENT v. REDEVELOPMENT Divide the total existinq ..bo.Does the site have > 35% or more ,� no impervious surface above by the existing impervious surface? size of the parcel and convert to a percentage. 6.5 % The proposal is considered new development. Answer yes questions in Figure 2.4.1 Flow Chart for New Development to determine project size (next page). The proposal is considered redevelopment Answer questions in Figure 2.4.2. Flow Chart for Redevelopment to determine project size (next page). - Applicants for "small' projects must comply only with Minimum Requirement #2 Construction Stormwater Pollution Prevention. Please submit the Small Project Certification (Worksheet "s). The proponent is responsible for employing the 12 Elements to control erosion and prevent sediment and other pollutants from leaving the site during the construction phase of the project. Pick up the Construction Stormwater Pollution Prevention (SWPPP) Best Management Practices (BMPs) Fact Sheet. Applicants for "medium" projects —those that must meet only Minimum Requirements #1 through 45 must submit Worksheet Al and 131, a stormwater site plan and a construction stormwater pollution prevention site plan (See Reference A1A and B1A for guidance).). " "Large" projects —those that must meet all 9 Minimum Requirements-- must submit Worksheet Al and 61, a stormwater site plan and a construction stormwater pollution prevention site plan (See Reference A1A and B1A for guidance). Large projects also may require engineering. See Worksheet L to determine additional large project requirements. APPLICANT SIGNATURE By signing the -Stormwater Calculation Worksheet, I as the applicant/owner attest that the information provided herein is true and correct to the best of my knowledge. I also certify that this application is being made with the full knowledge and consent of all owners of the affected property. (LANDOWNER OR AUTHORIZED REPRESENTATIVE SIGNATURE) (DATE) stormwater talc Worksheet 4R cede— REV. 5f3t12019 page 2 of 2 DEPARTMENT OF COMMUNITY DEVELOPMENT 621 Shcridan Strect, Port Townsend, WA 98369 Tel; 360.379.4450 1 Fax: 360.379.4451 WAY: vAv«.co.jeffersoli.Nva.us/coinmuniWde-,,clol2i-ntiit E-mail: dccl a)co Jcffc.rson.wa.us - d� STORMWATER CALCULATION WORKSHEET Scan the QR code to access the digital form PARCEL# G 1 -j �DCp PRcjEcr/APPLICANT NAME: - } j p p1 ��es ��U ►�� DETERMINING STORMWATER MANAGEMENT REQUIREMENTS: This stormwater calculation worksheet should be completed first to classify the proposal as "small," "medium," or "large." The size determines whether a stormwater Site Plan is required in conjunction with a stand-alone stormwater management permit application, building permit application, or other land use approval application that involves stormwater review. The basic information will also be helpful for completing a Stormwater Site Plan, if required. PARCEL SIZEME., SITE Size of parcel 3 I q q acres An acre contains 43,560 square feet. Multiply the acreage by this figure. Size of parcel in square feet) 5 & I~ 0S sglft Land -disturbing activity is any activity that results in movement of earth, or a change in the existing soil cover (both vegetative and non -vegetative) and/or the existing soil topography. Land disturbing activities include, but are not limited to clearing, grading, filling, excavation, and compaction associated with stabilization of structures and road construction. Native vegetation is vegetation comprised of plant species, other than noxious weeds, which reasonably could have been expected to naturally occur on the site. Examples include species such as Douglas fir, western hemlock, western red cedar, alder, big -leaf maple, and vine maple; shrubs such as willow, elderberry, salmonberry, and salal; herbaceous plants such as sword fern, foam fiower, and fireweed. LAND DISTURBING ACTIVITY, CONVERSION OF NATIVE VEGETATION, AND VOLUME OF CUTIFILL Calculate the total area to be cleared, graded, filled, excavated, and/or compacted far proposed development project. Include in this calculation the area to be cleared for: Construction site for structures o7 q sq/ft Drainfield, septic tank, etc. n /A sq/ft Well, utilities, etc. n1n sq/ft Driveway, parking, roads, etc. SOy Lawn, landscaping, etc. Other compacted surface, etc. Temporary construction area sq/ft sq/ft sglft sq/ft Total Land Disturbance �, 5�7 sqlft Answer the following two questions related to conversion of native vegetation: Does the project convert 3/4 acres or more of native vegetation to lawn or landscaped areas? Circle: Yes No Does the project convert 2'/z acres or more of native vegetation to pasture? Circle: Yes No Indicate Total Volumes of Proposed: (includes BMP T5.13 Fill Volume) Cut Fill (culyd) stormwater talc worksheet OR code - REV. 513112119 page 1 of 2 Figure 2.4.1 Flow Chart for New Development Star Here Does the site have 35% or more of existing impervious coverage? No Does the project result in 5,000 square feet, or greater, of new plus replaced hard surface area? Yes All Minimum .Requirements apply to the new and replaced hard surfaces and converted vegetation areas. This is a "large" project. Large projects refer to Worksheet L for submittal requirements. At a minimum, all large Project must submit Worksheet Al, BI,and Cor equivalent. See Redevelopment — - T Yes —_-► Minimum Requirements and Flow Chart Does the project convert (Figure 3.3) % acres or more of vegetation to lawn or landscaped areas, or No convert 2.5 acres or more of native vegetation to pasture? Does the project Yes f No result in 2,000 square feet, or greater, of new plus replaced hard surface area? Yes No Minimum Requirements #1 through #5 apply to the new and replaced hard surfaces and the Iand disturbed. Does the project have land disturbing activities of 7,000 Yes square feet or greater? No Minimum Requirement #2 applies. Complete "Smallr�-oject Certi-icatioo'4Vot Project must follow Construction Pollution Figure 2.4.1 -- Flow Chart for Determining Requirements for New Development Volume I —Minimum Technical Requirements —August 2012 2-10 Fact Sheet Worksheet S Small Project Certification This certification may only be used if you answer yes to all of the questions below (circle yes or no) . Otherwise, a submittal prepared by a licensed engineer may be required. Permanent and temporary drainage on site is designed to divert Stormwater away from my onsite septic system or any neighboring onsite septic system. If located in a Seawater Intrusion Protection Zone (SIPZ), I am able to infiltrate stormwater onsite using a dry - well or other method (full dispersion, downspout dispersion). My project will not discharge stormwater runoff into a critical area (including but not limited to: geohazard area or its 30-foot buffer, wetland or Fish and Wildlife Habitat Conservation Area) My proposal is a small project, which means it will create less than 2,000 square feet of new, replaced, or new plus replaced impervious surface area, and has less than 7,000 square feet of land disturbing activities as defined on the Stormwater Calculation Worksheet. I understand that my project must comply with Minimum Requirement #2 in the Department of Ecology Stormwater Management Manual as amended. I have read the Construction Stormwater Pollution Prevention Fact Sheet and will implement Best Manage- ment Practices (BMP's) as applicable to my project. Applicant Signature By signing the small project certification, I as the applicant/owner attest that the information provided herein is true and correct to the best of my knowledge. (LANDOWNER OR AUTHORIZED REPRESENTATIVE SIGNATURE) (DATE)