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EXHIBIT 7 <br /> STREETER POND - 001A <br /> The location of Streeter Pond (001A) is presented on Map 41. The profiles of the associated <br /> permanent ditches (Streeter Gulch Ditch, Southwest Tributary to Streeter, and Southeast <br /> Tributary to Streeter) are presented on Map 33, and the profile of Buckskin Draw Ditch is <br /> presented on Map 33A. Channel designs of these permanent drainage channels are provided in <br /> Exhibit 7, Item 14, Part E. <br /> This introductory text section is provided to better explain the evaluations performed for TR-105 <br /> as well as the previous evaluations previously performed by others for Streeter Pond. At the <br /> time the previous evaluations were performed, it was not the practice to include an introductory <br /> text section as is the now standard practice for this permit. <br /> History of Streeter Pond and Previous Modeling <br /> Streeter Pond was built in the late 1970s and was re-evaluated in detail in 2002. The physical <br /> and hydrologic parameters that went into the 2002 evaluation are described in WWC <br /> Engineering's July 30, 2002 letter to CWC, a copy of which appears in the Introductory Text of <br /> Volume 2D. The pond hydrology and sedimentology was again formally re-modeled using <br /> SEDCAD in 2006, which work was included in approved TR-63 dated 2/1/06. That modeling <br /> addressed the sedimentation performance of the sediment pond in the 10 year/24 hour storm for <br /> a watershed condition that was then described as the "Watershed Worst-case Reclamation <br /> Scenario." This worst case scenario assumes the pit has been backfilled and the entire watershed <br /> has been brought to final topography, thereby causing the entire 1308.5 acre watershed to be <br /> tributary to the pond. At this point some parts of the reclaimed watershed would still be in a <br /> relatively immature state of revegetation, thus requiring the use of higher runoff curve numbers <br /> than the ultimate completed reclamation condition. The TR-63 modeling also evaluated the <br /> dam's emergency spillway in the 25yr/24hr, 100 yr/24 hr storms and the spillway design storm <br /> specified in SCS TR60 for a Class B dam for this watershed condition. <br /> The proposed revisions to the post-mining topography associated with TR-105 result in a <br /> lowering of the final topographic surface in the upper reaches of this watershed. This also <br /> resulted in a slight increase (about 5%) from 1308.5 acres previously modeled in TR-63 to 1377 <br /> acres for the overall watershed area tributary to Streeter Pond. The previously approved spillway <br /> modeling is therefore deemed adequate and has not been re-evaluated for this TR-105. The <br /> SEDCAD models for those spillway evaluation cases (25 yr storm, 100 yr storm and SCS TR60 <br /> spillway design storm), have not been changed and remain presented on pages Exh. 7-SP-45 <br /> through Exh. 7- SP-127. <br /> The previous TR-63 sedimentology modeling for the 10 year storm has also been retained but <br /> only for reference. Its SEDCAD model output remains as pages Exh. 7-SP-24 through Exh. 7- <br /> SP-43, but it has been superseded with the new TR-105 10 year, 24 hour sedimentology model <br /> presented, with accompanying figures, starting on page Exh. SP-128. <br /> Exh. 7-Streeter Intro-1 Revision Date: 8/22/15 <br /> Revision No.: TR-105 <br />