1410 GRAND AVE 2018-01-02 MF Import

i GeoTest Services,Inc. � May 6,2011 � 1410 Grand Avenue,Everatt,WA Job No.11-0183 Slope Stability Due to the dense nature of the underlying glacial till deposits, a deep-seated rotational type failure affecting the site of the proposed improvements is unlikely to occur. Rotational failures can extend down into the subsurface to substantial depths. These failures typically leave geomorphic evidence of their existence on the slope. Typical indicators are head scarps, tension cracks, sag ponds, seepage zones, hummocky ground surface and slump biocks. Obvious visual indications of slope instability, such as those referenced above, or signs of excessive soil creep, as indicated by excessive numbers or curvatures of pistol-butted tree trunks, were not observed within the subject slope. Please keep in mind that the Pacific Northwest is seismically active and it is difficult to predict how the slopes at the site may behave during a large earthquake. Constructability Potential of Property GeoTest Services was asked to evaluate the constructability potential of the property. In our opinion, the flat, upper portion of the propeRy can be built upon utilizing standard, shallow concrete foundations with potential grade beams incorporated into the foundation design as the structure approaches the top of the slope. For the slope face itself, a deep foundation system such as auger cast piles or driven piers would be required to support a structure. The exact embedment depth for the foundations elements of structures on the slope face is beyond the scope of this letter and would require a full geotechnical evaluation. In our opinion, from strictly a geotechnical point of view, construction is feasible on 100 percent of the property. General Site Practices With respect to general site practices, which will help to maintain or increase the levels of stability on subject slope, we make the following recommendations: • Establishing and maintaining the healthy vegetation cover on the slope will best control long term erosion. We recommend maintaining the existing vegetation, and/or the introduction of additional native plant species to, if necessary, ta provide long-term erosion protection and to increase near surface slope stability. • If trees are to be removed, that may pose a fall hazard to the existing residence or proposed new garage, we recommend cutting the trees at the base and leaving the stump and root system in place. The root structure will continue to provide soil support for many years, until new seedlings in the vicinity replace the decaying materials. In our opinion, if the trees are removed as described above, the stability of the slope in the areas of removal should not be adversely affected. • Yard waste, excess soil fill, or other deleterious material should not be placed on or over the slopes. Such material smothers vegetation, retains water, and acts to destabilize the slope. Page 3 of 4