Laserfiche WebLink
Joe Dudash - ' June 11, 2009 <br />BRL: Updated table on Page B-9 to show the correct D50 size for ditch 14. Please see revised <br />page B-25 with note explaining how D50 riprap size was achieved. SedCad cannot handle a <br />flow of 35 cfs and a slope of 50% in the Simons/OSM steep slope method. The only way to get <br />an output was to use the Pader method, which generated a D50 size of 9". By putting the <br />information from SedCad into and excel spreadsheet, a D50 of 18" was determined to be the <br />correct D50 size. <br />D. The riprap size for the minimum grade for ditches F16, East Diversion Ditch and West <br />Diversion Ditch #2 are listed in Appendix B on page App-B9. It appears that the riprap <br />size for the maximum ditch grade should be listed Please revise Appendix B accordingly. <br />BRL: Updated Page B-9 to show that no rip rap is required for the East Diversion ditch, as the <br />maximum grade is 5%. Upon review of old drawings, the grade of the E. Diversion ditch used to <br />vary from 5-40%, but with the current design, the portion of 40% that used to be part of the E. <br />Diversion Ditch is now named Ditch F4, (which has been revised from a maximum grade of 34% <br />to 40%), a new SedCad sheet for F4 is attached as page B-15. The West Div Ditch #1 has <br />been revised to show 12" riprap for the lower portion, and no riprap required for the West <br />Diversion Ditch #2, as the maximum grade is 5% with the current design. Ditch F16 is correct <br />with 9" being shown. In addition, Figures 1 & 2 have been revised to show the correct location <br />of the riprap in the diversion ditches. Please also see revised pages B-32, 32i, 33, 33i, 34, & <br />34i. <br />E. There is no D50 riprap size listed in Appendix B for West Diversion Ditch #1. Please <br />include in the appendix the appropriate riprap size for the maximum ditch grade. <br />BRL: West Div Ditch #1 has been revised on page B-9. Please see response to part D <br />F. For ditches F7, F11 and F14, a freeboard of 0.3 feet is used in the ditch designs but <br />freeboard of 1.0 feet is used in the minimum ditch depth requirement list on Figure 3. <br />Please revise accordingly. <br />BRL: Figure 3 is updated with the correct ditch depth and required freeboard. Only Ditch F7 <br />needed to be updated on the Figure. Ditch F11 and F14 require 1.0 foot of freeboard, so their <br />revised SedCad pages are attached, pages B-22 & 25. <br />G. As shown in Section B-B `for Sediment Pond F on Figure 3, the elevation of the 10 <br />year-24 hour storage event is the same as the elevation of the emergency spillway. BRL <br />will need to ensure proper sediment cleanout so that, as required by Rule 4.05.9((2)(b), <br />no runoff from a 10 year-24 hour precipitation event can flow out of the emergency <br />spillway. <br />BRL: Comment noted. <br />Reclamation Cost Estimate <br />11. DRMS: The Division has determined that the reclamation cost estimate does not need to be <br />revised for TR-61.