2009-11-06_REVISION - C1981019 (2)

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9. As noted in the general comments section above, Colowyo is proposing changes to the Taylor Tributary Ditch that include increasing its length, changing its configuration and changing the point at which the Taylor Tributary Ditch, West Pit Ditch and East Taylor Ditch intercept it. Colowyo did not include any revised SEDCAD hydrologic modeling for the Taylor Tributary Ditch to verify its ability to safely pass the appropriate sized storm event (100-year, 24-hour event). This information is contained in Exhibit 7-14C of the permit. Please provide the Division with revised SEDCAD hydrologic modeling for the reconfigured Taylor Tributary Ditch. 10. Exhibit 7-14C does not contain any general information regarding the Taylor Tributary Ditch (all of the other ditches have this information on page 2 of their respective exhibit - see question 7 above for information on the East Taylor Ditch). Please provide the Division with this generalized information for the Taylor Tributary Ditch within Exhibit 7-14C. 11. Exhibit 7-14C contains SEDCAD hydrologic modeling information for both the Taylor Tributary Ditch and the West Pit Ditch. Duplicate (and possibly contradictory) SEDCAD modeling information for the West Pit Ditch is contained in Exhibit 7-14K. Although not a completeness issue, since Colowyo is required to update all of the SEDCAD hydrologic modeling for the ditches in the West Pit with Technical Revision 83 (including the Taylor Tributary Ditch and the West Pit Ditch), Colowyo may want to eliminate the West Pit Ditch information from Exhibit 7-14C to avoid duplicate and possible contradictory information with Exhibit 7-14K. Colowyo can use Exhibit 7-14C for information for only the Taylor Tributary Ditch. 12. As noted in the general comments section above, Colowyo is proposing changes to the Taylor Ditch that include decreasing its length, changing its configuration, changing its slope and changing the point at which it intercepts the Taylor Tributary Ditch. Colowyo did not include any revised SEDCAD hydrologic modeling for the Taylor Ditch to verify its ability to safely pass the appropriate sized storm event (10-year, 24-hour event). This information is contained in Exhibit 7-14L of the permit. Please provide the Division with revised SEDCAD hydrologic modeling for the reconfigured Taylor Ditch. 13. In addition to the SEDCAD modeling requested for the Taylor Ditch in question 12above, Colowyo will also need to update the general ditch information on Page Exh. 7-14L-2 (in Exhibit 7-14L). This information must reflect the proposed changes to the Taylor Ditch design contained in Technical Revision 83. Please update Page Exh. 7-14L-2 and submit it to the Division for review. 14. As noted in the general comments section above, it does not appear as though Colowyo is proposing any changes to the West Pit Ditch (with the possible exception of changing the point at which it intercepts the Taylor Tributary Ditch). If changes are proposed, please include new SEDCAD hydrologic modeling for