1601 FLORIDA DR Geotech Report 2022-10-25

P.O.Box 82243 Cobalt Kenmore,Washington 98028 Geosciences (206)3314097 February 13,2018 Mr.Paul Bustard Bustard Custom Construction PO Box 1243 Marysville,WA 98270 RE: Stormwater Management Recommendations Proposed 5-Lot Short Plat 1601 Florida Drive Everett,Washington Dear Mr.Hardt, In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to present our stormwater management recommendations for the proposed 5-lot short plat at the referenced location. In preparation of this report, we have reviewed a geotechnical report prepared by Liu and Associates dated September 10,2017. Site and Project Description The site is located at 1601 Florida Drive in Everett, Washington. The site consists of one irregularly shaped parcel(No.00393900701800) with a total area of about 0.63 acres. The south portion of the site is developed with a single-family residence and driveway. The remainder of the property is vegetated with grasses, ferns, blackberry vines, and small diameter trees. The site slopes downward toward the east and southeast at magnitudes of less than 10 percent and topographic relief of about 8 feet. The site is bordered to the northeast and southwest by single-family residences,to the northwest by a paved trail,and to the southeast by Florida Drive. The project includes construction of 5 new single-family residences within the property. We anticipate that the new residences will be multi-story, wood-framed, and have crawlspace areas. A new permeable pavement access road will extend onto to the site along the northeast property line. Stormwater management systems will include local infiltration trenches, permeable pavements, and connection to City infrastructure. Area Geology The Geologic Map of the Everett Quadrangle, indicates that the site is underlain by Vashon Glacial Till. Vashon Glacial Till is typically characterized by an unsorted, non-stratified mixture of clay, silt, sand,gravel, cobbles and boulders in variable quantities. These materials are typically dense and relatively impermeable. The poor sorting reflects the mixing of the materials as these sediments were overridden and incorporated by the glacial ice.