222 W CASINO RD Geotech Report 2022-10-25

GeoTest Services, Inc. May 3, 2019 Mukilteo School District 19-0194 Xa PURPOSE AND SCOPE OF SERVICES The purpose of this evaluation is to establish general subsurface conditions beneath the site from which conclusions and recommendations pertaining to project design can be formulated. Our scope of services includes the following tasks: • Exploration of soil and groundwater conditions underlying the site by advancing 4 test pits within the vicinity of the proposed portable building to evaluate subsurface conditions. • Laboratory testing on representative samples to classify and evaluate the engineering characteristics of the soils encountered. • Provide a written report containing a description of subsurface conditions, exploration logs, findings and recommendations pertaining to site preparation and grading activities, a discussion of site seismic considerations, foundation support of the allowable bearing pressures, bearing elevations, frost penetration and depth, general foundation recommendations and stormwater infiltration potential. PROJECT DESCRIPTION It is our understanding that a new, double portable building with a footprint of approximately 1,773 square feet will be constructed near the east property line, east of the existing portables. The new portable will be supported by a conventional concrete foundation and will incorporate a crawlspace under the portable. SITE CONDITIONS This section includes a description of the general surface and subsurface conditions observed at the project site during the time of our field investigation. Interpretations of site conditions are based on the results and review of available information, site reconnaissance, subsurface explorations, laboratory testing, and previous experience in the project vicinity. Surface Conditions The irregularly shaped, roughly 19-acre subject property is occupied in its more northern and eastern portions by the existing school building, asphalt parking areas, access drives and playfield/sports fields. Six existing portable units exist to the south of the existing school building. The subject property is bounded to the north by West Casino Road and to the south, east and west by previously developed, single and multi-family type residential construction. To the east of the subject area (planned portable location) a grade break of approximately 10 vertical feet separates site grades from the existing, private access roadways to the east. In general, the majority of the subject property is relatively flat (Image 1), but a slight rise in elevation was noted towards its southwestern extent. In general,the western portion of the property is generally vegetated with large,mature trees and other low-lying vegetation.Landscaped grasses and small trees occupy much of the otherwise undeveloped space in an around the existing parking lot and school facilities. Other than a limited presence of ponded surface water, associated with 1