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JD -7 Mine — Drainage Design Plan 33 <br />Figure 15. Photograph of Pit Diversion West Profile PDW -2 <br />(Facing east, 102 ft above section line and transition to natural channel into sub -basin N -E) <br />4.4.2 Pit Diversion Ditch — East <br />The Pit Diversion Ditch East (PDE) diverts stormwater from upslope around the existing JD -7 Open Pit <br />and routes it eastward into the adjacent sub -basin N -G. The PDE was initially constructed in the 1980s, has <br />been improved and maintained, and has achieved a stable channel configuration. The PDE is 996 ft in <br />length with an average bed slope of 0.0611 ft. The channel is normally dry, and flows only in response to <br />precipitation events. The PDE was modeled with a 2 -ft bottom width and 4.6:1 ft side slopes in the <br />WinTR -55 model. <br />4.4.3 Open Pit Waste Rock Pile Diversion <br />The existing Open Pit Waste Rock Pile Diversion structure ( OPWRD) diverts stormwater from the open pit <br />and upslope runoff areas eastward and northward around the existing Open Pit Waste Rock Pile. The <br />eastern segments of the OPWRD are characterized by shallow bed slopes (0.0114 ft/ft) and a broad channel <br />(Figure 9, Figure 16) with ongoing sediment deposition. The OPWRD is regularly maintained, and the <br />channel has achieved a relatively stable configuration over time. <br />The slope of the natural hillside changes to the west, and the western segments of the OPWRD are <br />characterized by somewhat steeper bed slopes (0.0699 ft/ft) and a more narrow, irregular channel <br />4149A.130926 Whetstone Associates <br />