5404 S 3RD AVE 2024-03-29 - Laserfiche WebLink

Geotechnical Engineering Evaluation and Engineering Geologic Assessment - REVISED NGA File No. 1300621 Sharp Residential Remodel October 12, 2021 Everett, Washington Page 5 CONCLUSIONS AND RECOMMENDATIONS General Based on our evaluation of property, it is our opinion that the site does not contain erosion or landslide hazards. Under current conditions, the site appears to be relatively stable with respect to deep-seated movement. The potential of nearby slopes impact on the site should be considered low, as the site is located several hundred feet from the top of the most critical steep slope in the vicinity of the property. It is our opinion that the site itself contains no geologic hazards as regulated by the City of Everett, and the potential for deep seated landslides should be considered low. Erosion Control The erosion hazard for the on -site soils is interpreted to be slight for the soils on -site, but actual erosion potential will be dependent on how the site is graded and how water is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed during construction should be protected from erosion. Erosion control measures may include diverting surface water away from the stripped or disturbed areas. Silt fences and/or straw wattles should be erected to prevent muddy water from leaving the site. Disturbed areas should be planted as soon as practical and the vegetation should be maintained until it is established. The erosion potential of areas not stripped of vegetation should be low. Site Drainage Surface Drainage: The finished ground surface should be graded such that stormwater is directed to an appropriate stormwater collection system. Final site grades should allow for drainage away from the structures. We suggest that the finished ground be sloped at a minimum downward gradient of three percent, for a distance of at least 10 feet away from the proposed structures. Subsurface Drainage: If groundwater is encountered during construction, we recommend that the contractor slope the bottom of the excavation and collect the water into ditches and small sump pits where the water can be pumped out and routed into a permanent storm drain while excavations are open. NELSON GEOTECHNICAL ASSOCIATES, INC.