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Stormwater_Control_Plan.pdfStorm Water Control -Plan Owner: Crosby Group ofWashington 2905 17(P',St SW Lynnwood, WA 98037 Site Location - 161. &'NafflLMe&dQm_iAafeM_)FAd E6onds, WA, 98026 P at -eel No. 00 5 13 1 OiOOO 5102 Prepared Greg Chandler (206) 650-0804 QEr, (I (10TVI U N"H This is a storm water control plan for a proposed 2630 sq ft single family residence located at 16120 N. Meadowdale Road Edmonds, WA 98026 The owner of this property is Crosby Group of Washington, located at 2905 170' ST SW Lynnwood, WA 98037. The contact for this project is Greg Chandler 425-745-0232 or 206-650-0804. This parcel is approximately 26,100 sgft and currently vacant. This lot slopes back to front as well as side to side. The slopes are not greater than 10% anywhere. It is covered with established grasses, small brush, and a few trees at the rear. The major portion of this lot is a documented wetland. It is delineated on all of the site plans as well as the 25' buffer from this wetland. The seasonal water from this wetland flows to the North and West into an established storm system established on 72nd St. There are no streams, swales or other drainage entering the buildable portion of this property that will affect the drainage of this lot. The proposed house plan for this lot is a 2630 sq ft split entry home. This project will create 2731 sq ft of new impervious surface with new roof, driveway, porch, patio and walkway. The majority of the storm water will be collected through a continuous 4" solid PVC drain line and first detained in a type 1L catch basin. It flows next into 61'of 18" pipe to allow sediment to settle. Finally into the control structure designed according to Edmonds standards for impervious surface to allow only the regulated amount of water into the existing storm system. (details on drainage plan provided ) A construction storm water plan has been designed that will reduce, eliminate, or prevent the discharge of storm water pollutants. The first step in the construction process will be to clearly flag or fence the clearing limits lines. This will be done by marking all of the silt fence, as delineated on the SWPPP, with orange flagging as clearing limits. The clearing limits as well as the silt fence will be installed just outside the 25' wetland buffer area. All areas that have or will be disturbed will be mulched or covered with black plastic. Every effort should be made to retain as much of the established grass as possible during the construction of the home. This will help disperse storm water. A construction access is the next step. Crushed rock will be placed on the lot at the driveway access point. This will help to avoid sediment being tracked onto the asphalt. All vehicles should be encouraged to remain on the asphalt to avoid sediment being tracked onto the road. Streets will also be swept regularly to prevent sediment transport offsite. Flow control is not required for this project. This storm water plan proposes to maintain the construction entrance and silt fencing or a brush barrier between the cleared areas and the wetland buffer area. Construction of these features will be completed before the clearing and grading of this site. Straw mulch will be used on exposed soils as necessary to limit erosion. This plan calls for stabilization of soils that remained un -worked for a certain time based on the time of year. Techniques for stabilization will include, but are not limited to mulching, plastic sheeting and/or hydro seeding. Notes are added to drainage plan regarding protection of the stockpile areas. Stock pile areas are identified on the plan and should be setback a minimum of 10' from any downhill property line. All disturbed slopes on site during construction are required to be protected with mulch or other means. No significant amounts of sheet flow will be directed to new cut or fill slopes during construction. Any drainage catch basins near this site that will need to be protected and maintained. There are no existing channels or outlets. The footing and downspouts will outlet to an onsite detention system. This system will be built using 2 type 1L catch basins and 6l'of 18" pipe between them. The outfall CB will have a control structure to regulate the amount of flow to the existing storm system. This system will be built using City of Edmonds standard details and approved tables. There are no outside chemicals expected to be used for the construction of this project. All vehicles working on this site will need to meet state requirements for emissions. De -watering is not expected for this project. The construction supervisor will be responsible for maintaining all BMP's during construction and working with the city to relocate BMP's as necessary as site conditions change. It will be the responsibility of the general contractor with the site supervisor to manage this project and coordinate with the city inspectors. Site inspection shall be done regularly by a person that is knowledgeable in the principles and practices of erosion and sediment control. This person must have skills to assess the site conditions and construction activities that could impact the quality of storm water, as well as effectiveness of erosion and sediment control measures to control the quality of storm water discharges. Whenever inspections and or monitoring reveals that the BMP's identified on the drainage plan are inadequate due to actual discharge or potential to discharge a significant amount of any pollutant, appropriate BMP's or design changes shall be implemented as soon as possible. The construction storm water plan shall be retained onsite or within reasonable access to the site. It shall be modified whenever there is change in the design, construction, operation or maintenance at the construction site that has or could have a significant effect on the discharge of pollutants to waters of the state. The storm water control plan shall be modified if during inspections conducted by the owner, or applicable local or state regulatory authority, it is determined that the plan is ineffective in eliminating or significantly minimizing pollutants in storm water discharges from the site. The plan shall be modified as necessary to include additional or modified BMP's designed to correct the problems identified. Revisions to the plan shall be completed within seven days following inspection. Installation and inspections of all utility trenches shall be scheduled and coordinated in such a manner as to minimize any open trenches, This project will be phased in to allow the areas where the grass is established to remain until such time required for final landscaping. This will help disperse some storm water during construction.