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Figure 22 (Continued) <br />contact the Division with regard to requirements for <br />potential alluvial valley floors. It should be noted <br />that the Division requires reconnaisance level AVF <br />mapping; usually, a 1:24,000 scale (or larger scale) <br />map showing topography and geographic features will <br />suffice for AVF mapping. <br />(7) Drainage Area Division <br />The boundaries of the watersheds or drainage areas <br />found within the permit area should be delineated <br />on the Hydrology Map. This delineation is necessary <br />for both sedimentation pond and diversion ditch <br />sizing. <br />(8) Diversion Structure - Unaffected Runoff <br />Any diversion structures (ditches} used to divert <br />runoff around the mining area should be indicated <br />on the Hydrology Map. These diversion structures <br />are useful in minimizing the amount of drainage area <br />that needs to be considered for the design of <br />sedimentation ponds. <br />(9) Diversion Structure - Affected Runoff <br />The diversion structures (ditches) used to channel <br />runoff from the mining areas should be identified <br />on the Hydrology Map. These structures are used to <br />prevent runoff from leaving the permit area and/or <br />disturbed area before treatment in a sedimentation <br />pond or other method approved by the Division. <br />(10) Stream Buffer Zone <br />No area within 100 feet (or greater distance if required <br />by the Division) of a perennial stream or a stream with <br />biological community will be disturbed by coal mining <br />activities. The Division may allow disturbance closer <br />than 100 feet, but the operator should contact the <br />6ivision before any disturbace is initiated. The 100-foot <br />stream buffer zone should be located on the Hydrology Map. <br />General Comments: The Hydrology Map should include the locations of <br />stoc ponds, springs, streams, irrigation ditches and other surface <br />water features. If the subsurface hydrology of the permit area is <br />complex, the operator should prepare a separate piezometric surface <br />map or other information such as cross sections to show location and <br />extent of subsurface water, areal and vertical distribution of aquifers. <br />6 <br />.~ <br />~,.. <br />t nr+ <br />