10200 19TH AVE SE COSTCO FUEL STATION 2016-01-01 MF Import

GEOTFCHNICAL ENGINEERING STUDY Costco Wholesale c/o Barghausen Consulting Engineers E-8556 January 13, 1999 Page 2 SITE CONDITIONS Surface The site is located on the northeast corner of the Costco property at 102�J0 — 19"' Avenue Southeast, Everett, Washington (see Vicinity Map, Plate 11. At the time of our exploration, the proposed development area consisted of asphalt pavement and landscaping islands. The properties to the north and south of the site are commercial developments. Additional pavement areas and the Costco warehouse are located west of the site. Subsurface The site was explored by drilling four borings at the approximate locations shown on Plate 2. Please refer to the Boring Logs, Plates A2 through A7, for a more detailed description of the conditions encountered at each location explored. F, description of the field exploration methods is included in Appendix A. The following is a generalized description of the subsurface conditions encountered. Fill soil consisting of inedium dense silty sand with gravel was encountere,� to a depth of one and one-half to three and one-half feet at the boring locations. Below the ;�II, dense to very dense silty sand with gravel was encountered to the maximum explored depth of twenty-five (25) feet below the existing grades. As part of our study, ECI reviewed a previous geotechnical engineering study for the existing development. The subsurface conditions encountered at our exploration sites were generally consistent with conditions described in the previous study. Groundwater Groundwater seepage was not observed at the boring locations. We do not anticipate seepage wiil present major problems for the proposed excavations; however, seepage may be encountered in excavations.. Groundwater seepage levels and the rate of seepage are not static, therefore, fluctuations in the level and rates can be expected depending on the season, amount of rainfall, surface water runoff, and other factors. Generally, the level and rate of seepage is higher in the �vetter winter months (typically October throiigh May. Eann Consulmnis, Inc. O