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upstream from the 006 Gulch confluence. This field is a small part of a much <br />larger ranching operation. Hay production from this field contributes <br />approximately 6 percent of the total ranching operations production. Mining in <br />the Seneca II -W South Extension Area is projected to increase the salinity levels <br />in Hubberson Gulch. TDS concentration of the irrigation water used on this <br />field is estimated to be 1787 mg/l which equates to a specific conductance of <br />approximately 2.4 millimhos/cm. In Tab 17, SP presents an estimate of <br />potential crop reductions based on the increased salinity level of irrigation water <br />in Hubberson Gulch. SP projects an estimated annual yield reduction of <br />approximately 4.5 tons from the subject AVF fields, which corresponds to 0.6% <br />of the total annual hay production for the ranching operation. This is considered <br />to be a negligible impact pursuant to the Division's 1998 material damage <br />guidance document. <br />b. Due to the extremely limited acreage of proposed disturbance within the Sage <br />Creek watershed, and the fact that regional ground water flow is to the west, the <br />potential for material damage to the quality or quantity of water supplied to the <br />AVF is negligible. No measurable impacts to the quantity or quality of water <br />supplying the Sage Creek AVF are projected. <br />c. Background salinity levels in the lower segment of Dry Creek from the Yampa <br />River upstream to Section 28, Township 6 North, Range 88 West are high <br />enough that no degradation of water quality is anticipated due to mining. <br />Agricultural areas potentially impacted by increased salinity levels are flood <br />irrigated grass and alfalfa haylands in Section 28, T6N, R88W. <br />With respect to the flood irrigated fields in Section 28, the application indicates <br />and includes detailed mapping and aerial photographs which show that the <br />subject fields are irrigated by water from J.C. Temple Reservoir #1, not from <br />Dry Creek. Thus, water supplying the irrigated fields would not be affected by <br />the mining operation. <br />There is no projected diminution of water quantity supplied to the Dry Creek <br />AVF. <br />3. Surface coal mining and reclamation operations have been and will be conducted to <br />preserve the essential hydrologic functions of alluvial valley floors outside the permit <br />area and to reestablish the essential hydrologic functions of alluvial valley floors <br />within the affected area throughout the mining and reclamation process (4.24.2). <br />An environmental monitoring system as described in Tab 15 of the permit <br />application has been installed, maintained, and operated by the permittee on all <br />alluvial valley floors during surface coal mining and reclamation operations and will <br />continue until all bonds are released in accordance with Rule 3 (4.24.4). <br />