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February 24, 2016 <br />Project: Inundation Mapping for Worster Dam <br />Vendor: Divide Canal and Reservoir Company <br /> Mr. Dale Leach, President <br /> P.O. Box 206 <br /> Eaton, CO 80615 <br /> Phone/Email: 970-454-3377 / info@eatonditch.com <br /> <br />Consultant: Tetra Tech, Inc. <br /> Mr. Dan Evans, P.E. <br /> 3801 Automation Way, Suite 100 <br /> Fort Collins, CO 80525 <br /> Phone / Email: (970) 206-4219 / dan.evans@tetratech.com <br /> <br />CWCB funding source: Severance Tax Trust Fund Operational Account <br /> <br />SCOPE OF WORK <br />Tetra Tech, Inc. (Consultant), at the direction of the Divide Ditch and Reservoir Company (Vendor), will <br />perform a dam breach modeling study and flood inundation mapping for the above dam. Worster Dam <br />is a Significant Hazard dam located in Larimer County within the South Platte River Basin. The dam is <br />located on Sheep Creek north of Fort Collins, CO. <br /> <br />Consultant or Vendor will submit the final report and mapping to the Colorado Division of Water <br />Resources, Dam Safety Branch, for approval. Grant funds will not be disbursed until the project has been <br />approved by the Dam Safety Branch. <br /> <br />PROPOSED METHODOLOGY <br />The Consultant shall perform a clear dam breach analyses in accordance with the State of Colorado <br />Rules and Regulations for Dam Safety and Dam Construction (1/1/2007), and the Dam Safety Guidelines <br />for Dam Breach Analysis (2/10/2010). Correspondence shall be with Kallie Bauer, P.E., of the Colorado <br />Division of Water Resources, Dam Safety Branch, to present preliminary dam breach parameters, water <br />surface profile modeling, and inundation mapping and to determine if field measurements are necessary <br />for critical bridges. <br /> <br />Inundation mapping for High Hazard dams shall show the calculated extents of the dam breach flood <br />wave. The mapping will also include cross sections at critical locations showing lateral and vertical flood <br />extents, flood wave velocity, and flood wave arrival time. Inundation mapping shall be extended <br />downstream to a location where no potential for loss of life and/or no significant property damage exist. <br /> <br />Inundation mapping for Significant Hazard dams shall show the route of the dam breach flood wave, the <br />estimated time of arrival of the flood wave at critical sections, and the estimated lateral extent of <br />inundation. The inundation mapping shall be extended downstream to a location where no significant <br />property damage exists. The inundation mapping requirements for Significant Hazard dams may be <br />modified for good cause, with the approval of the State Engineer. <br />