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Response: <br />a. The model in Exhibit 7-14P has been updated to reflect the approved curve <br />numbers from TR-78. <br />b. Area F has been included with the revised modeling. <br />c. We believe that no additional routing detail is needed. The current modeling <br />contains sufficient detail to capture hydrologic conditions. The temporary <br />ditches and associated sump divert and store runoff such that it does not <br />directly contribute to Prospect Pond <br />d. Volume 2E contains the current modeling for the Prospect Pond, which was <br />permitted under TR-63. This model provides the results for the 10 year, 25 <br />year and 100 year storm events using the former curve numbers. The <br />modeling assumed that the entire contributory area has been reclaimed or <br />topsoiled and seeded in preparation for reclamation. This worst case scenario <br />will in reality occur several years from now. Current conditions are not as <br />severe as this worst case. <br />Since that time the sequencing for East Pit Reclamation has been modified <br />under TR-80. It is the opinion of Colowyo that the current modeling is <br />sufficient for current conditions, as the worst case has not been realized. <br />Additional modeling will be completed for the Prospect watershed as we <br />approach the worst case hydrologic conditions. This action will happen in <br />conjunction with a PMT change in the area. See response to item 11. <br />11. Response not accepted. The issue of the Prospect drainage has been ongoing and <br />outstanding since at least the 20 August 2007 preliminary adequacy review letter for <br />Colowyo's Permit Renewal 05. Since that time there have been numerous letters, <br />discussions and one notice of violation issued regarding the Prospect drainage. The <br />implementation of alternate sediment control measures (including but not limited to <br />major surface roughening, an additional sediment pond upstream of the Prospect <br />Pond, stock tanks, etc.) is necessary to ensure the stability of both the reclamation in <br />the East Pit and the Prospect Pond embankment. As discussed during the NOV CV- <br />2008-004 process, failure of the Prospect Pond embankment could have <br />catastrophic results, not the least of which include possible damages to Colorado <br />State Highway 13 and the loss of life. Implementing these alternate sediment control <br />measures in the Prospect watershed is not an option. Colowyo must provide the <br />Division with a solid timeframe for the submittal of a Technical Revision addressing <br />the permanent measures for the Prospect drainage. Such a timeframe must <br />consider the importance of this issue and the fact that these measures will need to <br />be implemented beginning in the 2010 construction season (when the majority of the <br />internal ditches are removed and reclamation progresses in the Prospect <br />watershed). <br />Response: In order to address long term stability in the Prospect watershed, a new <br />PMT will need to be completed. Colowyo hopes to complete this within the next year, <br />but no time frame for such a revision was mentioned in the abatement measures. <br />Colowyo is aware that the Prospect watershed is a concern for the Division, and as <br />such will continue to strictly monitor the area.