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D <br />Mr. Rob Zuber <br />August 3, 2015 <br />Page 5 <br />spillways combined, as is presented in the output of the SEDCAD program. This will allow a <br />simple conformance check of the table and the submitted SEDCAD output. <br />In the course of this review, we noticed that the 10 year flow in the emergency spillway for the <br />Section 25 Pond was incorrectly filled in as the peak pool elevation from the row immediately <br />below this row, rather than "0.00 cfs" which should have been typed in that cell. Exhibit 7-23C, <br />Table 1 is being resubmitted with both of these changes made. <br />ITEM 17, In Table I emergency spillway lengths appear incorrect for some ponds. On <br />drawings they look longer than 20 feet. Please address this apparent error. <br />Response: The length of the level sections of the spillways can vary from 20 feet to 45 feet <br />depending on the geometry of the particular abutment in question. We generally use a length of <br />20 feet in design, and set the spillway invert as necessary to provide the desired freeboard. We <br />have checked this on several occasions and found that the peak pool elevation differential <br />associated with using a longer spillway of say 45 feet in the 100 year storm is on the order of an <br />additional 0.03 feet. This is insignificant in comparison to the construction tolerances and the <br />typical 12" riprap lining used in the spillway. Accordingly, no changes have been made to the <br />models.. <br />ITEM 18. Scales on some figures are incorrect (e.g., Fig C-3 in Exhibit 7-23). Please check <br />these and correct as necessary. <br />Response: Map scale errors have been corrected on Exh 7-23, Figures C1 through C4 and are <br />being resubmitted with this transmittal. <br />ITEM 19. On page Exh. 7-23C-1, in the third paragraph, the term "Practice Factor" is used. It <br />appears that this should be "Cover Factor" instead. Please address this apparent error. <br />Response: Colowyo has previously addressed a similar comment via email in May, 2015 (TR - <br />105), and is providing a shortened explanation with this submittal. It is correct to observe that it <br />was a typographical error in the text. The text on page Exh. 7-23C-1 should have been worded <br />"... the "Cover Factor" appropriate for loose dumped spoil "... instead of referring to the "Practice <br />Factor <br />The typographical error has been corrected, and page Exh 7-23C-1 is being resubmitted. <br />ITEM 20. Please explain the origin of the L (most are 145 feet) and S (most are 31%) input <br />values. <br />""10-." �. w, t l � n , <br />