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bedrock was slightly silty, waplastic, hard to very hard, fine to medium gained, moist and tan in color. <br />Claystoae bedrock was encountered is test hole 6 at a depth of approximately 7S Feet. The claystone bedrock . <br />was medium to highly plastic, hard, moist and dark gray in color. <br />Free goundwater was only encountered in test hole 4 at a depth of 13S feet at the time of drilling. However, <br />when meazured 23 days after the drilling was completed, goundwater was encountered in test holes 1, 2, 4 and <br />5 at depths ranging from 4 to 13 feet below the Bound surface. It should be noted that goundwater conditions <br />can be expected to fluctuate with changes in preapitation and runoff. <br />EMBANKMENT CONSTRUCTION <br />Foundation: The embankment will be placed oa the overburden soils and bedrock as described in the previous <br />section. The dam should consist of a "homogeneous embankment" constructed with the relatively impervious <br />overburden soils and a cutoff [reach extended in to the natural soils. The subsoils, exclusive of the topsoil are <br />suitable for support of the structure. Prior to placement of the fill materials, all of the topsoil and vegetation <br />should be removed and the exposed soils should be scarified to a depth of at least 8 inches, brought to within 2 <br />percent of the optimum moisture content and then recompacted to at least 95% of the standard Proctor density <br />az determined by ASTM D698. Due to the loose and very moist materials encountered in the embankment <br />area, stabilization of the subgade soils may be required prior to placement of the embankment fdls. If <br />stabilization of the subgade is necessary, we recommend that a layer of 6 to 12 inch rock be worked into the <br />base of the excavations until a stable surface is attained. A layer of stabilization fabric, such as Mirafi SIIOX or <br />an equivalent product, should then be placed over the stabilized subgade prior to placing embankment fdl <br />materials. Settlements on the order of 2 [0 4 inches can be anticipated for the overburden soils. Some minor <br />settlement of the embankment materials should also be anticipated. The settlement will be discussed further in <br />the overbuild section. <br />Toe DrainlDrainage Blanket: Due to the relatively shallow depth to goundwa[er and [be saturated condition <br />of the near surface sands and clays, a toe drain and/or drainage blanket may be requJred along the downstream <br />toe of the embankment. The requirements for and the size of the drain/blanket should be determined in the <br />field at the time of construction. The toe drain and blanket should consist of screened (1.5=mch minus) gavels <br />which are wrapped with a layer of Muafi 14pN or equivalent drainage Fabric. The drainage blanket should be <br />constructed with a minimum thickness of 2 Feet and the toe drain should consist of a 6-inch perforated pipe <br />surrounded by a minimum of 1 inches of screened gavels. <br />Cross Section: The proposed embankment will be approximately IS to 18 feet in height at the deepest point. <br />Both the upstream and downstream faces of the embankment will be constructed with 3 (horizontal) 1 <br />(vertical) slopes and a crest width of 20 Feet. The dam will be a "homogeneous embankment" constructed with • <br />the relatively impervious on-site materials encountered upstream of the embankment in the pond area. ; , <br />Job No. 97-3000 NonM.es[ Colorado Consul[ants, lnc. ['age 4 <br />