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<br />Boulder and Left Hand Repair of Outlet Works
<br />CWCBFeasibifityStudy
<br />NovemberS, 1999
<br />
<br />The average annual direct flow diversions between 1950 and 1996 through the Boulder and left Hand
<br />Ditch have been 964 acre-feet. The limited State Engineer's Office (SEO) data availabie for Boulder
<br />and left Hand diversions to storage between 1974 to 1996 show the average annual del iveries to
<br />Davis No, 1 and 2 and Hayden Reservoir have been 145 acre-feet and 215 acre-feet, respectively,
<br />Thus, the average annual diversion of the Ditch Company's direct flow and storage water rights has
<br />been 1,324 acre-feet.
<br />
<br />The Ditch Company's pro-rata ownership in the North Boulder Farmers Ditch Company also provides
<br />a water source to shareholders, The average annual headgate diversion at the North Boulder Farmers
<br />Ditch between 1951 and 1980 was 4,689 acre-feet. The Ditch Company's average annual share of
<br />those diversions is approximately 1,260 acre-feet. Thus, the average annual total water diverted for the
<br />Boulder and left Hand Irrigation Company shareholders is approximately 2,584 acre-feet or
<br />approximately 19 acre-feet per share (2,584 acre-feet/136 shares),
<br />
<br />Appendix B summarizes the direct flow and storage diversions of the Ditch Company and the North
<br />Boulder Farmers Ditch Company direct flow diversions,
<br />
<br />Need for the Proiect
<br />
<br />The Ditch Company is undertaking this project to continue to utilize Twin lakes as an equalizer
<br />reservoir and provide supplemental irrigation water.
<br />
<br />The existing outlet from Twin lakes is a 30-inch diameter CMP approximately 62 feet long. Inspection
<br />of the outlet pipe by Rocky Mountain Consultants, Inc. (RMC) and the SEO revealed the pipe has
<br />experienced some corrosion, and is in need of repair or replacement. The outlet gate is also corroded,
<br />and the outlet gate concrete headwall is cracking (see photographs on the following page), Dennis
<br />Miller, a Senior Professional Engineer from the SEO, in a December 4, 1996 letter (see Appendix C) to
<br />the Ditch Company has given notice that the pipe needs to be repaired by December 31, 1999, The
<br />SEO has also given notice to the Ditch Company in a letter from Jack Byers, dated June 17, 1998 (see
<br />Appendix D) that the existing facility at Davis No, 1 is hydrologically inadequate, The SEO has
<br />required the Ditch Company to engage a registered professional engineer to evaluate the problem and,
<br />if necessary, design improvements to the completed by June 30, 2003,
<br />
<br />A hydrology study was performed by RMC.' The study concluded that the existing spillway at Twin
<br />lakes is not adequate to pass the design inflow flood, and a new spillway is necessary at the easterly of
<br />the two Twin lakes (a.k,a, Davis No, 1), Also, the existing crest of Davis No, 1 needs to be regraded
<br />and does not accommodate the turnaround of vehicles,
<br />
<br />,
<br />
<br />"Davis No, 1 Dam, Evaluation of Hydrologic Adequacy," prepared by Rocky Mountain Consultants,
<br />Inc. for the Boulder and Left Hand Irrigation Company, May, 1999,
<br />
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