2010-12-09_REVISION - C1982057 - Laserfiche WebLink

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2. With regard to Hubberson Gulch, Sage Creek and Dry Creek, the activities will not materially damage the quantity or quality of water in the surface or ground water system (4.24.3(3) and 2.06.8(5)(a)(ii)), and the proposed activities will comply with the requirements of the Act and the Regulations with respect to alluvial valley floors (2.06.8(5)(a)(iii). a. On Hubberson Gulch, a 26 acre subirrigated and flood irrigated hayfield, and a point of diversion are located in portions of Sections 16 and 21, TSN, R88W. The fields are downstream from Pond 016 and 017 discharge points and upstream from the 006 Gulch confluence. This field is a small part of a much larger ranching operation. Hay production from this field contributes approximately 6 percent of the total ranching operations production. Mining in the Seneca II-W South Extension Area is projected to increase the salinity levels in Hubberson Gulch. TDS concentration of the irrigation water used on this field is estimated to be 1787 mg/1 which equates to a specific conductance of approximately 2.4 millimhos/cm. In Tab 17, SCC presents an estimate of potential crop reductions based on the increased salinity level of irrigation water in Hubberson Gulch. SCC projects an estimated annual yield reduction of approximately 4.5 tons from the subject AVF fields, which corresponds to 0.6% of the total annual hay production for the ranching operation. This is considered to be a negligible impact pursuant to the Division's material damage guideline. b. Due to the extremely limited acreage of proposed disturbance within the Sage Creek watershed, and the fact that regional ground water flow is to the west, the potential for material damage to the quality or quantity of water supplied to the AVF is negligible. No measurable impacts to the quantity or quality of water supplying the Sage Creek AVF are projected. c. Background salinity levels in the lower segment of Dry Creek from the Yampa River upstream to Section 28, Township 6 North, Range 88 West are high enough that no degradation of water quality is anticipated due to mining. Agricultural areas potentially impacted by increased salinity levels are flood irrigated grass and alfalfa haylands in Section 28, T6N, R88W. With respect to the flood irrigated fields in Section 28, the application indicates and includes detailed mapping and aerial photographs which show that the subject fields are irrigated by water from J.C. Temple Reservoir #1, not from Dry Creek. Thus, water supplying the irrigated fields would not be affected by the mining operation. There is no projected diminution of water quantity supplied to the Dry Creek AVF. Seneca II-W Findings Document 57 C1982057 Permit Renewal No. 5 December 9, 2010