881 OLYMPIC BLVD Geotech Report 2023-12-29

COBALT c bdtCwmen� , = �rl�lGEOSC IE NC Es P.O'BOX axM Kenmore, WeaM1Mgloa 98oxa July24,2023 II"ECEO V ED Jonathan Witham Ilu(r,�1U/ jpwitham[ahotmail.co JUL 28 2023 REu Geotechnical Evaluation Onpermifted vegetation Removal CITY OF EVERETT 881 Olympic Boulevard Permit Services Everett,Washington In accordance with your authorization, Cobalt Geosuences, ULC has prepared this letter to discuss the results of our gemechnical evaluation of steep slope areas near the above -referenced location. Site Description The site is located at 881 Olympic Boulevard in Everett, Washington. The site consists of one bregularlyshaped parcel (No. 00464700004002) with a total area of 1.02 acres. The southeastern portion of the property is developed with a single-family residence, detached structure, driveway, local wags, and patio areas. The areas near the residence are vegetated with grasses, bushes, and sparse hoes. This portion of the property slopes downward from east to west at magnitudes of 5to 20 percent and relief of about 30 feet. There is a shallow undulating ravine feature just west of the residence that was formerly overgrown with underm ry, invasive vegetation, and trees. The ravine has a northerly slope of 5 M 15 percent with no to 5o percent magnitude side slopes extending downward to the east and westintothefeature. Thesideslopereliefisabout2oto25feet. There are steep slopes located northwest of this feature that extend downward to the northwest at magnitudes of about 8o to over i2o percent and relief of about rho feet. This slope is heavily vegetated with trees and undemtory. The site is bordered to the northeast by a residential property, to the south by Olympic Boulevard, to the east by N. Park Drive, and to the northwest and west by undeveloped land. Recent work at the site included local removal of undershery and invasive plants from the shallow ravine feature and nearby areas west of the residence. Future work could include additions and new asphalt near the residence. Based on our site visit and photographs, not all vegetation was removed from than area and no vegetation was disturbed from the steeper slopes further west. Area Geology The Geologic May of the Bverett Gandranele, indicates that the site is near the contacts between Vashou Glacial TID, Vashon Advance Outwash, Transitional Beds, and Whidbey Formation. Vashon Glacial Till includes relatively dense mixtures of silt, sand, gravel, and clay in a consorted matrix or dlamict. These deposits are typically impermeable and often overlie Vashon Advance Outmeh. www.cobaltaeo.com (206) 331-1097