Laserfiche WebLink
<br />The immature soils would not be adequate to support general agronomic <br />activities, and development would probably be limited to improved <br />pasture. Because of the size limitations of this area and the lack of a <br />well developed soil capable of supporting sustained agronomic <br />production, the terrace area on the north side of the North Fork does <br />not meet the criteria of an AVF. <br />Downstream from the town of Somerset, the valley opens up and the <br />applicant has identified a much larger body of alluvium. Areas within <br />Sections 13 and 14 have been identified as currently supporting <br />agriculture. In the permit approval issued July 29, 1981, WECC was <br />notified of a positive alluvial valley floor declaration for the North <br />Fork of the Gunnison River in Section 18, T13S, R90W and Sections 13 and <br />14, T13S, R91W. A stipulation was included in the original permit <br />approval requiring that the applicant demonstrate that the mining <br />operations' fresh water usage will not materially damage the quantity <br />and quality of water supplying the alluvial valley floor. <br />Changes in the quantity of water supplied to the AVF depend on the <br />difference between water used and water discharged to the North Fork of <br />the Gunnison River. Total water use is expected to be about 150 <br />acre-feet per year during maximum projected production. This represents <br />less than 0.04% of the average annual stream flow on the North Fork. <br />Since less than 70% of this use is deemed to be consumptive use, the <br />loss is actually less than 0.03% of the average stream flow. In <br />addition, water is withdrawn during higher flows when WECC's water <br />rights are in priority. During low flow periods when calls for water <br />exist, WECC would not be withdrawing water. <br />Water quality changes resulting from discharge of waste water will not <br />constitute material damage because no measurable change in water quality <br />is expected to occur. Of the 200,000 gallons/day maximum projected use, <br />38,000 gallons/day (28.5 acre-feet/year) would be required for potable <br />water use. Consumptive use of potable water would be minimal. Assuming <br />no consumptive use, one would expect a discharge of less than 0.06 cfs <br />during plant operation. This use and return flow is insignificant <br />compared to the flows in the North Fork of the Gunnison. Even during <br />the lowest flow on record (17 cfs) for the 1934 through 1979 period of <br />record on the North Fork at Somerset, the potable water use would be <br />less than 0.4% of the flow. The return water will be treated to meet <br />NPDES effluent limits and should pose no problem for downstream <br />irrigation use of AVF's. <br />The remaining 162,000 gallons per day of water use is for coal spraying <br />and dust suppression activities. The estimate is conservative and <br />includes a 15% contingency for leakage. Consumptive use is difficult to <br />estimate, but should be less than 85%. The return flow along with any <br />seepage water would be collected and routed to Sediment Pond MB1. This <br />water is then treated and either released to the North Fork or <br />recycled. Assuming 138,000 gallons/day (0.2 cfs) is the consumptive <br />21 <br />