Laserfiche WebLink
3. Groundwater <br />Below this gravel zone is the very thick and impermeable Lewis Shale. Test pits on the Bunn <br />Ranch site reveal that the ground water table is approximately 4 feet below the surface. The <br />levels will fluctuate depending on the time of year and in response to Yampa River levels. <br />There are no groundwater wells within 600' of the operation that are used as a source of water. <br />5. Water Consumption for the Operation and Water Rights <br />Since the mine will encounter water 4 feet below the surface of excavation, and permanent lakes <br />will be left as part of the reclamation plan, consumptive use totals are calculated below. A well <br />permit has been applied for with the Division of Water Resources. The well permit will cover pit <br />pumping as well as all consumptive uses for the operation. During the mining stage of the <br />project, consumptive uses will be limited to the evaporation from the sediment pond, road <br />watering, plant water sprays, and gravel retention. After mining, the consumptive use will be <br />lake evaporation. All consumptive uses are shown below: <br />After Mining and Reclamation <br />1) The permanent lakes will total approximately 23 acres in size, which may fluctuate <br />depending upon the groundwater level. Total average water surface is expected to be 22.9 <br />acres. Since the lake bottoms and sides are always saturated due to the level of alluvial <br />water, no losses will occur due to infiltration. Losses will occur due to evaporation at the <br />water surface. With an approximate annual evaporation of 40" annually (Colorado <br />Annual Evaporation Chart NOAA Tech Report NWS33), this results in a consumptive <br />use of 76.3 acre-feet annually using an area of 22.9 acres. <br />During Mining <br />1) During mine operation, consumptive use will occur as result of mining the gravel <br />exposing it to air before it run through the crushing/screening operation and trucked off <br />site. Based on Colorado Division of Water Resources guidelines, groundwater depletions <br />are equivalent to the volume mined below the water table. The use will be based on <br />Gehrman Pit October 09 G-3