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Colorado Water Conservation Board Members <br />Mr. Thomas Browning, P.E., CWCB <br />Review of Lacy Report for Chaffee County Whitewater RICD <br />May 10, 2005 <br />Page 7of9 <br />Typically, sophisticated analysis is conducted with two dimensional and other special hydraulic. <br />analyses, and by physical modeling in laboratories. Three dimensional hydraulic computer model <br />programs are available to hydraulic engineers, which allow determination of detailed wave forms, <br />flow patterns, and optimization of the structure, including performance and cost effective design. <br />In the process, problems are always recognized in the analysis, which are mitigated and the <br />design optimized, including consideration of a range of flows. Materials and construction details <br />are evaluated for hydraulic and stability performance. None of this has engineering has been <br />done, or at least it has not been provided. <br />The report makes reference to "basic hydraulic formulas" and "numerous HEC -RAS models of <br />similar structures ". These related calculations should be provided. The phrase "models of similar <br />structures" implies that no HEC_RAS models of the structures in the RICD application has been <br />done, and they certainly have not been provided. Further, there is no proof that optimization of the <br />design, required flows, and whitewater performance has taken place. <br />7, The changes to the floodplain and flood hazard caused by the proposed plan should be <br />documented, and was not. There should have been an evaluation of alternative approaches <br />and/or design modifications. If there are rises or unavoidable impacts, then their mitigation and <br />mulit- agency approval should be specifically cited. In the present case, there has to a rise in flood <br />and normal flow levels caused by the weirs, jetties, and other whitewater features as a matter of <br />basic hydraulic science. This rise should be quantified. Opinions as to significance without <br />engineering proof are not acceptable practice. Because there has to be a rise, it has to be <br />mitigated, by a variety of possible actions and facility design modification. None are identified. <br />8. Final performance review, design optimization, and identification of maintenance and operation <br />needs should be conducted. This evaluation should include assessment of the flows and amount <br />of time that satisfactory minimum and optimum performance is achieved. Cost information should <br />be provided, including future measures that may be necessary to achieve all objectives, goals and <br />criteria. <br />19.-) <br />12596 WEST BAYAUD AVENUE, SUITE 200, LAKEWOOD, CO 80228 <br />303.458.5550 FAX 303.480.9766 <br />