2211 GIBSON PL Geotech Report 2023-04-06

t 1 August 18, 2014 Gibson Bluff L&A Job No. 14-056 Page 6 and the total number of blows for the last 12 inches was recorded on the boring logs as N- values of the Standard Penetration Tests. The test borings were located near the top of the steep slopes along the north and west side of the site. All three test borings encountered an Esperance sand soil unit with its surface at about 3.5 to 7.5 feet below existing ground surface. The Esperance sand deposits were consisted of gray, medium-dense to dense, fine to medium to coarse sand with trace gravel. Overlying the Esperance sand soil unit is a layer of thin topsoil and a layer or layers of weathered soil of silty to slightly silty, fine sand. A light-brown to light- gray deposit of very-stiff, fine-sandy silt was encountered at 31.0 feet in Test Boring B-1, which appears to be of the Whidbey formation soil unit. Groundwater Condition Groundwater was not encountered by any of the three test boring drilled on the site. The Esperance sand deposits underlying the site is of moderately high permeability and would allow stormwater to seep through easily. Stormwater infiltrating into the ground would be perched on top of the underlying Whidbey formation soil unit. The depth to and the amount of perched groundwater would fluctuate seasonally, depending on precipitation, surface runoff, ground vegetation cover, site utilization, and other factors. It appears the underlying Whidbey formation soil unit is at 31.0 feet or deeper beneath the site. Therefore, groundwater table should be at such a depth under the site that it would likely have little impact on the proposed development. LIU & ASSOCIATES, INC.