Laserfiche WebLink
<br />; <br /> <br />Ms. Honey R. Moschetti, President <br /> <br />-9- <br /> <br />December 19, 1994 <br /> <br />In its present condition, DeWeese Dam does not meet current Colorado dam safety standards. <br />It is our opinion that the 12-foot high raise section is not structurally capable of withstanding the <br />overtopping estimated to result from current estimates of the 50 percent PMF. Based on our <br />visual observations of the dam and the information discussed herein, we do not believe that <br />current conditions present an immediate hazard to the dam as it is presently operated. Remedial <br />actions will be necessary within the next several years to bring the dam into compliance with <br />current dam safety standards. <br /> <br />Recommendations <br /> <br />We recommend that the DeWeese-Dye Ditch and Reservoir Company continue its present efforts <br />to bring DeWeese Dam into compliance with dam safety standards. The water storage provided <br />by the dam and reservoir represent an important resource to the shareholders. Failure to address <br />the existing dam safety concerns will likely result in storage restrictions imposed by the SEO, <br />which could severely reduce the amount of water available to the shareholders. <br /> <br />We further recommend that the Company continue the phased project approach discussed in our <br />September 27, 1994 proposal. By performing the work in defined phases, informed decisions can <br />be made at each step regarding the best scope of work for a subsequent phase. At each step, it <br />will be important to develop a detailed scope of work which will effectively contribute to the <br />economical resolution of the identified dam safety concerns. Our specific recommendations are <br />as follows: <br /> <br />1. Hydrologic Analyses. An incremental damage assessment (IDA) should be performed <br />to determine the inflow design flood for the dam. The IDA would examine <br />incremental damages and hazard potentials associated with a dam failure during floods <br />less than the 50 percent PMF. Using previous estimates of the PMF as a basis, we <br />believe that an IDA would allow a considerable reduction in the flood magnitude <br />selected as the inflow design flood, which could significantly reduce the total costs <br />required for remedial modifications. <br /> <br />The hydrologic analyses will need to be performed in accordance with requirements <br />of the SEO. Selection of the inflow design flood will require approval by the SEO. <br /> <br />2. Conceptual Designs of Alternative Remedial Concepts. Conceptual designs of <br />alternative remedial concepts should be developed following completion of the <br />hydrologic studies and selection of the inflow design flood. <br /> <br />The conceptual designs would include appropriate structural analyses of the dam and <br />raise section. These analyses would be performed to a level of detail necessary to <br />develop cost effective remedial designs, and to verify the overall structural <br /> <br />94311\DDREPORTLTR <br />