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Colorado Reef Fresh Weber Reservoir <br />April 6, 2009 <br />Page 4 <br />Earth Hngitssadno ConssltMAS, I. Q. <br />elevations at the time of our exploration. Groundwater depth should be ca_rlcful monitored <br />to identify any significant fluctuations in the groundwater levels which could impact the <br />potential lining of the Moor of the reservoir. <br />Bedrock elevations in the northeast corner of the reservoir appear to be on the order of site <br />elevation 480. Excavations in this area may encounter the top of the bedrock stratum. We <br />expect the bedrock in this area would be readily excavatable and .with a moderate to MO., <br />plasticity could be considered for blending with granular materials to develop a low <br />permeability lining or could be placed as low permeability liner. <br />We understand significant seasonal variations in water depths are expected in the reservoir. <br />If used for r �z.''rind, ui- site clayey So ils would be stn jestt tV vsrsfLr, rusu g UZZICRUC CIPI KIng <br />which could destroy the integrity of the lining system. The -clay soils should be protected <br />from drying to maintain effectiveness as a low permeable barrier. <br />!Preliminary design indicates slopes on the interior of the reservoir on the order of 4 to 1 <br />(horizontal to vertical) wish exterior slopes on the order of S to l or 6 to ' . We aarnticipate <br />those slopes could be developed with the site matmials. <br />We have started phase II testing for this project which will iracliude determination of t«e <br />hydraulic conductivity of the anticipated low permeability barriers and development of shear <br />O <br />r v►F i� -C f� C .�f 0 .s nl n�.oii.nti�n il io aaCr� <br />�'t al i da'�. r 51V- �IGLS.- fL: L!„'.+3'�LlLLl LE3dC a %!(dLGa1 4�; S w'�144L :E`JE gul VYSiLeQ_iafai Yvai_ � u Yra <br />to help establish design parameters for the embankments and low permeability lining. <br />GENERA'. COMMENTS <br />The analysis and recommendations presented in this report am -bawd upon the data obtained <br />from the soil borings performed at the indicated locations and from any other information <br />discussed in this report. This report does not reflect any variations which may occur between <br />borings or across the site. The nature and extent of such variations may not berme evident <br />until constriction. If variations appear evident, it will be necessary to re- evaluate the <br />mer_:?"_: dati ns `f this report. <br />It is recommended that the geotechnical engineer be retained to review the plans and <br />specifications so co meets can be made regarding the interpretation. of <br />our geotechnical recommendations in the design and specifications. It is further <br />recommended that the geotechriical � girleer he retained fhr testing a nd oh <br />ge+vatinng during <br />