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<br /> <br />~~_~~~f~~}:j;Jf&~f$j1~{t5~:.'~:l~~;<::d~'_'2~:~~~{:>~)s.!::;i/:~Ji;,h:~W;.i~.~:i:!',i&}i)'J~~~~ugt~;"_;;.'.~.,,;,.,,;_,.:.~~, <br /> <br />e <br /> <br />'.:.' '~;',,;M, ". . '^"~, <br /> <br />~ <br /> <br />Long Hollow Reservoir <br />Feasibility Study <br /> <br />the final dam, which will reduce seepage through the abutments and the darn foundation, At this <br />point in the investigation, WWE has included in the feasibility-level design three features to <br />reduce seepage, The first is a grout curtain cut-off wall beneath the center of the darn, This <br />grout curtain wall extends to a depth of 100 feet and consists of angled grout holes spaced on 10 <br />feet center to center across the entire crest length of the darn. In addition, we have obtained a <br />cost estimate for sub-excavation of 10 feet of material from beneath the dam and replacement of <br />the material with compacted fill consisting of the Lewis shale, Finally, a seepage blanket will be <br />placed on slopes and the floor of the reservoir for a distance of approximately 200 feet upstream <br />from the darn. The seepage blanket will be constructed by removing the natural fractured rock in <br />the area and replacing it with a compacted fill consisting of Lewis shale. The final configuration <br />of seepage control features will depend on additional geotechnical investigation, <br /> <br />An instrumentation program of surface survey monuments and piezometers to monitor water <br />pressure in the embankment at multiple levels is recommended for the enlarged embankment and <br />included in the cost estimate. <br /> <br />The enlarged LHR is shown on Exhibit 3.1-1. The exhibit contains a table that shows the <br />coverage and acreage on adj acent land parcels resulting from the enlargement. <br /> <br />An opinion of probable cost for the 5,400-AF enlarged darn and reservoir is presented in Exhibit <br />6-1. The estimated cost for the reservoir is approximately $13,476,000. This estimate is <br />considered to be accurate within a range of ",15 percent, The cost per AF of storage will be <br />$2,496. The operation, maintenance, and repair costs for the LHR are estimated to be <br />approximately $22,000 per year for operation and maintenance and approximately $30,000 per <br />year for replacement reserve. These costs are based on extrapolations from the Red Mesa <br />Reservoir operated by the Red Mesa Ward Reservoir Company. <br /> <br />This report has been prepared in accordance with generally accepted engineering practices in this <br />area for use by the client for planning purposes. The conclusions and recommendations <br /> <br />991-077.120 <br />March 2005 <br /> <br />Wright Water Engineers, Inc. <br /> <br /> <br />Page 5 <br /> <br />