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Pocock Racing Shells September 15, 2016 JN 16391 Page 2 short slope that declines to an existing paved parking/drive area for the adjoining commercial facility. This slope has a height of approximately 10 feet and was created by excavation for the development of that property. To the east of the Pocock property the ground slopes down to Hardeson Road. This slope is taller than 10 feet and was also created by legal grading associated with the street. The slopes to the west, north, and east of the site are manmade. We observed no indications of recent instability on these slopes during our visit to the property. While on site, three test pits were conducted to explore the subsurface conditions in the planned development area. The approximate locations of these test pits are shown on the attached Site Exploration Plan. Test Pit 1 was conducted at the northeast corner of the existing slab to assess the conditions beneath the current foundation that surrounds the existing slab. This test pit showed the footing to be bottomed at a depth of approximately 2 feet, and it bears directly on very dense, glacially -compressed, gravelly, silty sand. The remaining two test pits found fill extending to a depth of 3 to 4 feet. Beneath this fill was dense, gravelly, silty sand that extended to the maximum 8-foot depth of the test pits. The dense to very dense soils encountered in the test pits are typical for the conditions we have found on developments in the surrounding area. Slight seepage was observed at a depth of one foot in Test Pit 2. This represents subsurface water that is perched on top of the less permeable fill. After extended wet weather, it is relatively common to find subsurface water perched on top of the dense to very dense, native soil, which is essentially impervious. CONCLUSIONS AND RECOMMENDATIONS We recommend that the new foundations for the addition be supported on the dense to very dense native soils. The existing foundations surrounding the western slab were found to bear on dense, native soils and are suitable to support the western portion of the planned construction. We have reviewed the criteria for a Landslide Hazard Area under Title 19, Section 37.080 of the Everett Municipal Code (EMC). The site and surrounding lots do not exhibit indications of historic landslides. There are no springs or seepage on the slope, and we observed no indications of stream incision or undercutting of the slope's toe. The steeper slopes around the site have also been...created by -previous .grading -associated-with - legal. development.--..- Based _on_our-observations,. the site does not meet the EMC's criteria for a Landslide Hazard Area. If the recommendations of this report are followed, the planned new building addition can be constructed without adverse impacts to the stability of the surrounding slopes. The planned construction will be situated over 25 feet from the taller eastern slope, which is more than sufficient to protect the planned development in the event of future shallow soil movement on that slope. No setback from the western and northern slopes is necessary. The recommendations presented in this report are intended to maintain a slope stability safety factor in excess of 1.5 and 1.1 for slides in both static and seismic conditions, respectively. The development area does not meet the criteria for an Erosion Hazard Area. The slopes around the planned development area will not be disturbed, which will maintain the existing vegetation and the resistance of the slopes to erosion. Typical erosion control measures for the planned development will be appropriate. A wire -backed silt fence should be erected at the northern and eastern edges of the work area. Existing pavement and gravel surfacing should be maintained GEOTECH CONSULTANTS, INC.