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^ MestWater Engineering <br />2516 FORESIGHT CIRCLE, #1 GRAND JUNCTION, COLORADO 81505 (970) 241-7076 FAX (970) 241-7097 <br />December 20, 2011 <br />Ken Nelson, President <br />North Delta Irrigation Company <br />122 1. Highway 50 <br />Delta, Colorado 81416 <br />FEASIBILITY STUDY APPROVAL <br />Pursuant to Colorado Revised Statutes 37-60-121 &122, and <br />in accordance with policies adopted by the Board, the <br />CWCB staff has determined this Feasibility Study meets all <br />applIble requirements for approval, <br />Sig Data <br />RE: Feasibility Study of Upper Portion of Canal System <br />Consisting of Inverted Siphon, Unlined Tunnel and Open Ditch Canal <br />Dear Ken, <br />This letter represents a feasibility study and capital improvement plan of the NDIC's canal system <br />along a segment taken out of service duhrig the 2011 irrigation season. The basis for our evaluation <br />includes preliminary field data collected September 19 and 28 by WestWater Engineering (WWE-), <br />geotechnical engineering input from Dennis Lambert, P.E. of" Lambert & Associates (attached letter <br />dated November 22, 2011), construction expertise from Tim Malone of Beavers Construction <br />Company, and detailed field survey data provided by Mountain Valley Survey (MVS) of Paonia <br />(attached e-mail transmission December 14, 2011). We have also addressed review comments on <br />draft interim reports dated November 30 and December 5, 2011 from the Board. <br />Prelin-tinary design criteria is also provided for suggested improvements to reinstate full utilization <br />of the canal system for long-term serviceability in future irrigation seasons. It is intended that the <br />NDIC can utilize information contained herein for financial planning, and to coordinate applicable <br />permits for Construction, With regulatory agencies in advance of the construction schedule, <br />Summary of Irrigation System Failure <br />A I-mile stretch of the ND1C canal system was taken Out of set-vice during the 2011 irrigation <br />season due to rock and soil debris front a collapse within an irrigation tunnel. The turinel is located <br />directly east of Highway 65, beneath a residential development along 1950 Lane between the <br />Gunnison River and Cory in Delta County, Colorado, <br />The attached 24" x 36" Plan sheet, labeled Figure 1, generally shows the subject segment of the <br />canal system on an aerial photo based map. The inverted siphon, open ditch canal and tunnel are <br />shown with different line types to distinguish unique methods offlow conveyance. Approximate <br />cross sections of the tunnel and the open ditch are also presented to further describe existing <br />configurations, The lower portion of the Plan sheet includes a profile of the existing flowline, <br />hydraulic gradient, and ground surface. The profile and cross sections utilize standard engineering <br />Aa I Cn,­mvA07'F3JAV Aha <br />