1304 80TH ST SW EVERETT SCHOOL DISTRICT 2018-01-02 MF Import

I Everett School District— Bus Facility �� March 24, 2006 — Storm Drainage Report Page 2 II. PRELIMINARY CONDITIONS SUMMARY Existing Conditions Existing site conditions used for storm system design calculations were taken from the topographic survey, visual inspection through visits of the site, and design calculation,' completed during the original development of the two parcels in 1980 and 1983. The original design calculations for each property were completed by Kegel & Associates, Inc. and Lovell-Sauerland & Associates, Inc. and are located in Appendices D and E, respectively. The project site is bordered by Commercial property to the west, north, and east of the project site. To the south of the project site is State Route 526 right-of-way. Two commercial driveways provide access at the north side of the property from 80u' Street SW. Existing conditions used for storm system design calculations will be taken prior to the original development in 1980. The site conditions listed below are for the currently developed site. The east half of the project site was originally developed in 1980 and previously operated as a fishing supply store. There is currently an existing metal structure with a footprint area of approximately 3,400 square feet located on the northern half of the property. The existing building is surrounded by concrete sidewalks and asphalt concrete pavement used as parking for the fishing supply store. The south two-thirds of this half of the site is gravel surfacing used as overflow storage for various fishing items. An existing wetland is located at the southwest comer of the site, which receives minimal amounts of stormwater from the project site. The west half of the project site was originally developed in 1980 and previously operated as a metal fabrication shop. There is currently an existing metal structure with a footprint area of approximately 16,000 square feet located on the northern half of the property. The existing building is surrounded by concrete sidewalks and asphalt concrete pavement used as parking for the metal fabrication shop. There is a metal shop building with a footprint area of approximately 5,300 square feet located south of the main metal structure. The south one-half of this half of the site is gravel surfacing used as overflow storage and parking for the metal fabrication shop. There is approximately 400 feet of 36"and 48"CMP detention pipe located east and south of the main structure, which detains and controls stormwater runoff from the western half of the project site. The natural discharge location for the project site is at the northeast corner into an existing wetland located on neighboring property The stormwater from the existing wetland exits through a culvert crossing 80`^ Street SW toward the north. See Section III for offsite drainage system description.