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<br />1`i. Hydrologic calznce: Ground water - Rules 2.U4.u, 2. U, .:. <br />L.U~.~~s~, [.uc.o(.i) and 4. U: <br />1. Based on drilling information and field ooservation of operational <br />mine pits at Grassy Creek by Division staff; ground water <br />occurrence within the consolidated bedrock units to be excavated <br />' is quite limited. However, there is the potential that over a <br />long period of time a water table will become established in the <br />spoils of the backfilled pits. <br />' At least one monitoring well should be installed to the base of <br />the dacnfilled spoils in each reclaimed mine pit to establish the <br />presence or absence of water in the reclaimed spoils and monitor <br />' the quality of the spoils water (if present). Quarterly <br />monitoring of tiater levels and water quality will oe required. <br />1 <br />VI1. Alluvial Valley Floors - Rules 2.06.8 and 4.24 <br />The applicant has madE a negative alluvial valley floor determination <br />based upon an alluvial valley floor reconnaissance investigation. A copy <br />' of the reconnaissance investigation was provided to the Division in <br />September 1930, and a portion of the investigation (the two page text) is <br />included in the application. <br />' The investigation identifies potential alluvial valley floors along gage <br /> Greek and Fish Creek. These areas, however, are not hydrologically <br /> adjacent to the proposed operations and do not need to be considered at <br /> this time. Upper Grassy Creek would not be identified as an alluvial <br />' valley floor because the valley is narrow, steep, and would not be useful <br /> for either flood irrigated or subirrigated agricultural activities. k <br />' lower area along Grassy Creek adjacent to the county road, includes <br />approximately 20 acres of alluvium. This area has not been flood <br /> irrigated, and only about two acres of it are subirrigated. The <br /> applicant indicates that no known irrigation is practiced in similar <br /> valleys within a two Wile radius, that irrigation would create erosion <br />' problems, and that irrigation would be economically unsound. Based upon <br /> this information the z~plicant concludes that the area along Grassy Creek <br />' is not an alluvial valley floor. <br /> ln= utvrston Dues not necessarily disagree witn this conclusion. <br />' However, in order fur the Utvision to mare its own negative alluvial <br />ltl be <br /> valley floor determination, some additionl tnformatton shou <br /> incorporated into the permit application. <br />1 1. The NYF reconnaisance map showing areas of flood irrgation and <br /> areas of unconsolidated strea~ulaid deposits must de included in <br /> the permit application. <br /> <br />