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<br />(p. 7, par. 2) The report states that the velocity distribution can be used to show that the stage- <br />discharge relationships are the same before and after improvements. As stated, this and <br />subsequent claims are not accurate. <br /> <br />(p.8, par. 2) "... demonstrates that the boating park is in an .. ,,". This is an unsubstantiated <br />claim. <br /> <br />3. Accuracy otthe HEC-RAS model <br />(p. 9, last par.) No citation to support claim that HEC-RAS can have errors of 20-40%. <br /> <br />00- <br /> <br />This section of the report is quite confusing. The report maintains that HEC-RAS is not <br />accurate for a variety of reasons yet the author then uses HEC-RAS to verify claims. This is <br />contradictory. Both statements cannot be valid. <br /> <br />4. Power indice cY <br />(pp. 10- ) T e report states that the power surface index (PSI) can be used to evaluate the <br />design of, tructure in the context of geometry, usability, and functionality. It states that the PSI <br />considers many more factors than the power index (PI) (note that t terms are not defined)) <br />including width and surface roughness. Furthermore, the report onveys that the PSI (and'P1) <br />were not intended (by the developers) to be used to evaluate the sign of a single structure <br />at a discrete location. These metrics were developed to represent the average characteristics <br />of a reach of river ai29 hen~.,are applicable to slalom courses. The author then proceeds to <br />use a slightly modified version of the PSI (he calls it the freestyle surface index) to justify the <br />design. This is contradictory ant:rreqUlres clanflcatton. Furthermore, the theoretical basis a~ <br />hence,) the legitimacy of the application of either index in this design is not established. A <br />searcn for the references~cited by the author was unsuccessful. <br /> <br />(p. 13) The validity of the Freestyle Surface Index is unsubstantiated and claims made based <br />on the index are suspect. <br /> <br />/'.'.\I~~ <br />1\ () \f'-' <br />~V <br />~~~JY -P <br />/,,~~~\J'l <br />0"r>..r(J <br /> <br />5. Similarity modeling, river hydraulics and morphology <br />(p. 13, 14) Reference is made to the capacity, aspect ratio and morphology. These terms are <br />not defined within the context of this project a~ hen~an accurate evaluation cannot be <br />made. ~ <br /> <br />e. <br />(p. 14, 15) In a general sense, the statement that a flow rate which creates an acceptable , <br />experience on a small river or in a relatively small manmade facility cannot be assu a to t ~ <br />effectively provide the same hydraulic condition on a larger river is reasonable. e differing <br />morphology, geometric scale, relative roughness, and other factors will affect 'the hydraulics of <br />the system. The term hydraulic conditions includes not only those obvious characteristics <br />valued by river enthusiasts but also factors like s~er::rtjr..arlSf>ert-eapacity-need <br />preserve iVAr morPholo:q~~aUv.~ay provide opportunities to reduce the <br />. Imum flow rate on the lar live ou Jeo Izing recreational quality or river stabil' . <br /> <br />6. Engineering design \S <br />(p. 15, 16) The report states that a sensible aJ:l roach to design is to use field proven <br />techniques. This is a fundamental notion at t e core of engineering design~arn from past <br />successes and failures. The use of carefull collected empirical evidence from existing designs <br />that have been proven to be successful' a legitimate and common part of the design <br />process. No evidence has been presented in these reports tl;\ah;blgga&ts that this benchmark <br />has been met. <br />