C153445 Feasibility Study - Laserfiche WebLink

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. PROJECT SUMMARY The Summit Reservoir and Irrigation Company (Summit) owns and operates an irrigation system consisting of three reservoirs and an extensive ditch network. The facilities are located in north- east Montezuma County in extreme Southwest Colorado. The irriga- tion system provides about a 50% supply of wate~ to 4,000 acres of privately owned land. Summit was incorporated in 1907 as a not-for-profit organiza- tion. Summjt has 400 shares of stock issued to 110 shareholders. The smallest shareholder has ~ share and the largest 26 shares. Summit has a good credit rating with the Wichita Bank of Coopera- tives and several local banks. '\ The subject of this report is Summit Reservoir, the largest reservoir-in the Su~it system with a capacity of 4,800 acre-feet (AF).Summit Reservoir was initially constructed in 1905, then raised to its present capacity in 1938. A dam, the west dike, and south dike form the reservoir which have a combined length of about 8,600 feet. The embankment is a homogeneous section that is 45 feet high at the dam but is usually less than 20 feet. SUlnmit Reservoir has not had any improvements or modifica- tions since it was enlarged in 1938;. as a result, the reservoir now requires improvements and repairs ,{n several areas. The Colorado State Engineer,. as part of the Dam Safety Program, inspects Summit Reservoir once a year because it is classified as high hazard. The last inspection was June 1983. Several defi- ciencies were noted in the structure which need immediate atten- tion. The deficiencies can be'summarized into four categories:' 1) Recontouring 2) Raise dike crest 3) Backfill below west outlet 4) Place filter blanket on middle south dike Recontouring involves reshaping the ground below much of the dike to remove existing ponds and improve the drainage. Material was borrowed from just below the toe when the reservoir was enlarged in 1938. The borrow areas were not reshaped at that time and now collect seepage through the embankment resulting in brush, weeds, and insects. Also, the ponds hinder adequate inspection of the embankment and could create stability problems by saturating the toe of the embankment. ' There are.four locations where there is not sufficient slope to naturally drain water away from the toe. Drains had previously been dug but they do not have sufficient gradient. The ground will be recontoured to remove ponds and install the necessary surface drains. Also, on the four drains, measuring flumes will be installed to monitor seepage. -1-