5107 SOUND AVE 2017-01-14 - Laserfiche WebLink

July 21, 2014 Two Single-Family residences L&A Job No. 14-065 Page 6 to light-gray, loose to soft, silty fine sand to fine-sandy silt, about 3.9 �eet thick. This layer of weathered soil is underlain to the depth explored by a deposit of gray, hard, clayey silt which appears to be of a Whidbey formation soil unit. Test Pii 2located on top of an earth b�nk along the south side also encountered a layer of topsoil andlor disturbed soil of loose, organic, silty fine sand, about 3.0 feet thick. Test Pit 3, located in the northwest corner area, encountered a layer of topsoil, about 8 inches thick. Underlying the topsoiUdisturbed soil in Test Pit 2 and the topsoil in Test Pit 3 is a layer of weathered soil of light-brown to brown, loose to medium-dense, silty to slightly s,e,J� �;a,,Q C,,;��, �?�,��,�� . �� -.� f�nt tl-a3�?r. �[Tn��rlyix�s� t�is l�ye�- c�f ea�a�h�red soil tc� th� depths explored is a deposii o� %rown-gray co iigh�-brow�l to light-�cay, medium�deiise, fine to medium and fine to coarse sand, locally containing some gravel, vvhich appears to be of an advance outwash soil unit. GROUNDWATER CONDITIUN Groundwater seepage was encountered by all three test pits at about 4.0 feet in Test Pit 1 and at 7.0 feet in Test Pits 2 and 3. The influx of groundwater seepage was estunated at about 1.0 to 3.0 gpm (gallons per minute). The Whidbey formation silt deposits at shallovv depih are of eartremely low permeability and would perch stormwater infiltrating into the more permeable surficial soils. The level and amount of this near-surface, perched, groundwater seepage would fluctuate seasonally and would vary depending on type of soil, site terrain, vegetation cover, site utilization, etc. Groundwater may dry up in the dry summer months and accumulate and rise in the wet winter season. The perched groundwater on the hillside would flow laterally along the suxface of the Whidbey LIU & ASSOCIATES, INC.