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Addendum to Rational for Approval Recommendation Page 4 Application for Stone Gravel Pit Permit No. M-97-089 February 17, 1998 Based on information contained in the application, as described above, the applicant has sufficiently described the direction and rate of slope for all reclaimed lands within the proposed permit area. Issues relating to the adequacy of Exhibit F, Reclamation Map, and its detail of final topography of reclaimed lands, are identified in the Proposed Pre-Hearing Conference Order, item 5.a., and addressed in DMG 1 /20/98 Rationale for Approval Recommendation. 4. The inaccuracies and lack of detail are highlighted by the proposed reconstruction of the intermittent stream that runs toward the northeast. Review of the reclamation map shows that the sVeam has the same direction and rate of slope as the entice 158 acre parcel under consideration, even through it runs /tom the center of the parcel to the northeast. and then turns to run a/most directly east. This /eaves unanswered the question of where waters in the eight mining units that slope to the east-southeast will run. Map measurements from Exhibit C, Mining Map, indicate that the gradient of the un-named intermittent drainage channel, referenced within the Technical Revision, is approximately 2.5%. Map measurements from Exhibit C also indicate that pre-mining slopes have an east aspect with 1.5% to 3.3% gradients (-1.5% to -3.3% gradient to the east). Revised Exhibit F, Reclamation Map, and revised Exhibit E, Reclamation Plan, indicate that the un-named intermittent drainage channel will be reconstructed to its approximate original location. Inlet and outlet elevations shall match the undisturbed portions of the channel and the reconstructed channel shall follow its approximate original course and distance. Therefore the overall gradient of the reconstructed drainage channel will be similar to the original gradient. Map measurements from the Reclamation Map indicate that the overall gradient of the reconstructed channel will be approximately 2.5%. As noted above in item 3, mining activities will remove the small rise located at or near Unit VIII. The small rise originally directed surface drainage to the east-southeast for Units I -VIII. However, final reclamation will result in overall slopes of -1 % to -3% to the east. Precipitation occurring within all reclaimed mining units will drain downhill, to the east. Significant runoff from reclaimed areas is not anticipated due to mild slope conditions, moderate erosion potential of the native and replaced materials, the application of 2 tons/acre mulch, application of seed mix containing species tolerant to alkaline, saline and drought conditions, and the sediment containment berm located along the downslope (east) perimeter of affected lands. During active mining operations, disturbed area drainage will be contained within the depression created by excavation activities. Affected area drainage not contained within the pit will be detained by the sediment containment berm located along the downslope