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PROJECT SERVICE AREA <br />The service area of The Highland Ditch Company, Inc. is shown on Figure 1. The service area <br />encompasses approximately 40,000 acres of land of which approximately 25,000 acres is irrigated by <br />the Highland Ditch Company. Crops grown in the service area includes corn, pinto beans, sugar beets, <br />wheat, barley, oats, alfalfa and grass hay. The gross income from production on this land is estimated <br />at approximately 10 million dollars per year. <br />WATER RIGHTS <br />The company's decreed water right for Foothills Reservoir has an appropriation date of July 13, 1910, <br />a Priority No. 11, Third Series, for 4,340 acre -feet of water to a decreed gage height of 45 feet. A <br />conditional.refill decree was issued with a date of December 31, 1929, with an appropriation number <br />of 23S, Third Series. This decree was later canceled by the District Court in 1965 due to lack of <br />evidence showing diligence. Appendix B contains a copy of the recorded decrees for Foothills <br />Reservoir and Appendix C contains a copy of the reservoir storage chart. <br />Foothills Reservoir is utilized to store water from the Saint Vrain River during the spring runoff. The <br />reservoir is filled through a supply canal that starts near Lyons and the discharges are back to the river <br />directly below the reservoir. The water is exchanged in the river system by the water commissioner <br />to allow the Company to withdraw water at its main headgate near Lyons which is upstream of <br />Foothills Reservoir. <br />NEED FOR THE PROJECT <br />Foothills Reservoir Dam was rehabilitated in 2001 and with the construction of a new spillway and the <br />installation of a drainage system on the dam face and the installation of a toe drain. During 2002 the <br />dam was not filled above gage height 39 feet and the dam and drain system installed functioned <br />properly. In 2003 the reservoir was filled above gage height 39 for the first time since the 1970's and <br />excess seepage was noted in the drain system with wet spots on the dam face. The reservoir was slowly <br />raised to gage height 42 with the seepage increasing, but not at an alarming rate. At gage height 41.5 <br />the seepage was measured at approximately 0.25 cfs in the toe drain system and at approximately gage <br />height 42.3, the seepage increased dramatically to approximately 1.5 cfs. The reservoir was lowered <br />to gage height 39 feet and has been limited to that elevation since then. <br />Due to the alarming increase in seepage above gage height 42.3 feet, the Owner decided to initiate an <br />investigation of the dam to determine the cause. This was initiated in January 2004 consisting of both <br />a geophysical investigation and a drilling and sampling program. This program is described in detail <br />in the design report listed as APPENDIX F included herein. <br />Based on the extensive geotechnical investigation and the conditions encountered, the Owner decided <br />to repair the dam by cutting off the seepage through the upper portion of the dam. Three alternatives <br />were evaluated, as described herein, to determine the most feasible method to accomplish this goal. <br />The three alternatives evaluated include 1) a clay core trench in the center of the dam, 2) a slurry trench <br />Foothills Dam- 03.076 Page 2 <br />