6700 HARDESON RD BASE FILE 2018-01-01 MF Import

� Intracorp July 16, 1998 : ;: •il: c� E-3E92-6T0 Pap� 4 As part of this study, we conducted a reconnaissance of the west alope. The purpose of our reconnaissance was to look for indications of recent or pa �t instability. Our reconnaissance indicates the presence of three debris flow acarpa on tha west slope above the subject aite. Debris flows occur when the surficial loose aoil layer becomes saturated during heavy rains and fails, flowing downslope. They may ba caused by h�avy precipitation, groundwater seepaga and uncontrolled surface water at the top of the slope. The debris flow scarps observed on the west slope appear to be relatively old features and pre-date the construction of Seaway Tract 1 at the top of the slope which is directlnp surface water away from the siope. Several trees on the Iower portion of the slope are curved, indicatiny downslope creep of the surficial soii layer. The creep appears to be occurring the relatively loose colluvium, slope wash and old fill deposits an the lower portion of the slope. Tha apptoximately forry (40) feet of fill which was placed at the toe of the slope in 1996 should buttreas the toe af the slope and mitigate the creep potential. During ourTeconnaissance, we did not nbserve indications of recent slope instability on the west slope. Construction Saffiacks The City of Everett Environmentally Sensiti•�e Areas regulations requires a twenty five (25) foot setback buffer from the toe of slopes with gradients of 40 percant or steeper. This would include the west slope. Howeve�, in our opinion, with tne improved drainapa conditions at the top of the west slope and the buttressing of the toe of the slope by the structural fill the buffer can be reduced. In our opinion, it should be feasible to extend pavements to the toe of the slope. Buildings should maintain a setback of twenty-five (25) feet. Erm CarWcann. Ine. �