to ± El. 403 near the west side of the site. The topography also indicates a base <br />flood elevation ranging from ± EI. 401.2 to El. 401.7 across the property. The <br />bank of the Willamette River lies within ± 260 to 270 feet of the east property line. <br />The vegetation within the parcel consists.. of predominantly short grass and <br />scattered fir and fruit trees. The terrain along the river bank to the east is heavily <br />wooded. <br />Subsurface Conditions <br />The soil units encountered across the site include the following: <br />Topsoil. A relatively thin layer of topsoil was encountered in all the test pits. This <br />unit typically extends to a depth of ± 0.8 to 2 feet and consists of medium stiff to <br />stiff, low to medium plasticity clayey silt with scattered organics. <br />Silty Clay (alluvium). In the test pits located above the floodplain (all test pits <br />except TP-2, TP-4, TP-7 and TP-10), the topsoil is underlain by medium plasticity <br />silty clay. This unit was moist and medium stiff to stiff at the time of the field <br />exploration. The stratum extends to ± 2 to 4 feet. <br />Silt (alluvium). In the test pits located within the floodplain, the topsoil is underlain <br />by low plasticity silt with trace to some sand. This unit was moist and medium <br />stiff to stiff at the time of the field exploration and is ± 2 to 4 feet thick. <br />Sandy Silt/Silty Sand. The above soil units are typically underlain by medium stiff <br />to stiff, loose to medium dense sandy silt to silty sand. This stratum is ± 1 to <br />5.5 feet thick. <br />Sandy Gravel and Cobbles (alluvium). Medium dense to dense sandy gravel with <br />scattered 8-inch minus cobbles were encountered at depths ranging from ± 2 to <br />11.5 feet, and extended to the limits of our explorations. This unit was wet at the <br />time of our field work. <br />Specific details of the soil conditions encountered in each test pit are provided in <br />the appended test pit logs. <br />Ground Water <br />Ground water seepage was encountered in the test pits located within the <br />floodplain (TP-2, TP-4, TP-7 and TP-10) at depths ranging from ± 10 to 11 feet. <br />The rate of infiltration was observed to be rapid. Based on the proximity of the <br />site to the Willamette River and the presence of relatively permeable gravels at <br />deeper depths, we anticipate the local ground water conditions correspond. closely <br />to the river elevation. Areas of perched water may be encountered at relatively <br />shallow depths during the wet winter and spring months due to the presence of <br />fine-grained soils with low permeability. <br />Oakleigh Meadows Cohousing February 12, 2013 <br />Geotechnical Investigation Project 2131004 1 447 <br />Eugene, Oregon 2. Willard C. Dixon Architect, LLC <br />