2010-07-09_REVISION - C1981019 (3)

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Technical Revision No. 78 Permit No. C-1981-019 July 9, 2010 The approved plan in the East Pit will result in the following on-the-ground conditions: At the end of 2010, 36.5 acres of additional pit are to be reclaimed immediately up gradient from the 2009 reclaimed area. This parcel will result in the extension uphill of the North Tributary of the East Pit Ditch and will effectively finalize reclamation in the Prospect Ditch subwatershed. Temporary ditches B and C are to be eliminated (except for a small portion of ditch B). The North Tributary of the East Pit Ditch is to be completed up to station no. 25 at the end of 2010. In 2011, 47.4 acres of the east end of the East Pit are scheduled for reclamation. This area will extend up gradient to the Final East Pit Ditch. At this point in time, a significant number of reclaimed acres (about 100) in a relatively young hydrologic condition will drain down the North Tributary and the Final East Pit ditches, before entering the South Collection Ditch on the way to Prospect Pond_ Given the approved schedule, it is clear that the model proposed in TR-78 will only be applicable for a short period of time, likely only a few months. The worst case hydrologic scenario is approaching as Colowyo continues to reclaim. For this reason the Division asked questions 9, 10 and 11 below. Adequacy Review Comments This question was resolved with the 24 June 2009 Colowyo submittal. 2. This question was resolved with the 24 June 2009 Colowyo submittal. 3. This question was resolved with the 24 June 2009 Colowyo submittal. 4. Response Partially Accepted. Colowyo has included the requested sump information as Figure 3. This information is acceptable. Colowyo stated in their response that a commitment to submit an as-built is already in the approved permit. While Colowyo does state that the requirements of Rule 4.05.9(14) will be followed, the commitment (contained on Page 4.05-7) only pertains to that portion of Rule 4.05.9(14)(a) that discusses the requirement for a yearly inspection by a registered professional engineer. There is no mention in the permit text regarding providing the Division with a construction report (as-built certification) following completion of the sump. The Division's original comment from the 6 November 2009 Third Adequacy Letter remains. Please note that the sump will require an as-built design and PE certification pursuant to Rule 4.05.9(14) following construction. A commitment to submitting the certification must be included in the narrative. 5. Response accepted. Colowyo provided the necessary sump sizing. 6. Response not accepted. Approval of the temporary sump requires that the information requested in this question be submitted precisely because of the unique and temporary nature of this designed structure. Please provide information in the appropriate portion of the text in Volume 1 that discusses the temporary Prospect sump. Pursuant to Rule 2.05.3(4)(a)(ii), the text needs to include a detailed plan for operation and maintenance of the temporary