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_15_ V. Hvdrolooic Balance: Surface Water - Rules 2.04.5. 2.04.7 For a description of the surface water hydrology of the permit and adjacent areas, and a discussion of the impacts of mining on surface water; refer to the "Description of the Hydrologic Environment" and "Probable Hydrologic Consequences of Mininy" portions of Section IX Probable Hydrologic Consequences and Cumulative Hydrologic Impacts tudy, of this document. The surface water quality, diversions, sediment control, and discharge structures sections of the application have been reviewed by the Division. The surface water quality and quantity portion of the permit application can be found on pages 2.04-2b through 2.04-28 of Volume IB, and in Appendices XIII and XIV of Volume III. Alternative Water Supply Information is provided on pages 2.04-29 through 2.04-33 of Volume IB. Sediment and Drainage Control is presented on pages 2.04-37 through 2.05-40 of Volume IC, and Appendices XX and XXI of Volume II and III. The sediment and drainage control system at Hawk's Nest consists of a series of diversionary works at the upland extreme of the disturbed area boundary, a diversionary and collection culvert system and 5 sediment ponds. All disturbed areas are drained into sediment ponds. The designs for all components of the system are located in Volume IV, Appendix XXI of the application. Sediment control system drawings and pond design drawings are contained in Volume IB, Exhibit 2.05.3A through I. All of the ditches have been reviewed for compliance with Section 4.05.3. All ditches have been found to meet all of these requirements, with the exception that several ditches have velocities which are erosive under design flow conditions. Section 4.05.3(bj(a) requires that ditch linings be designed "to pass safely the design velocities". The ditches of concern are: West Mine Diversion, East and West Lirnbs, and the East Mine Diversion, East and West Limbs. All of these ditches have design velocities of 8 to 10 fps. For this reason, the Division imposes the following stipulation: STIPULATION No. WITHIN THREE MONTHS OF PERMIT ISSUNNCE, THE PERMITTEE WILL LINE BOTH LIMBS OF THE EAST ANO WEST MINE DIVERSIONS WITH COMPETENT RUCK RIPRAP WITH A D50 OF NOT LESS THAN SIX INCHES IN ORDER TO PREVENT EXCESSIVE EROSION OF THE CHANNELS, OR PROVIDE APPROPRIATE GALCULATIUNS WHICH DOCUMENT NON-EROSIVE UELOCITIES.