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. • • Dan Mathews -2- January 18, 1982 covers about two-thirds of the five-year permit area. This aquifer is a un- confined water table aquifer, and as such is recharged directly from precipita- tion, snowmelt, perennial streams and irrigation systems. Water from wells in this aquifer is used for domestic and stork water supplies. The stream channels of Ward and Williams Creeks are developed in the "Glacial- Alluvial Aquifer". The streams are perennial and are the source of water for irrigation systems which provide water to irrigate pastures, crop lands and orchards both above and below the permit area. Most of the 1,197 acres of irrigated lands in the area are developed on these unconsolidated alluvial materials. Ward and Williams Creeks, irrigation systems, and irrigated lands will be under- mined by the Red Canyon No. 1 and No. 2 mines. Beneath the'Glacial-Alluvial Aguifer", there exists extensive subcropping of the E and D coal seams, with subcrop lengths of approximately 5,750 feet and 2,375 feet respectively (from Map 2.04.5-1). The E Seam ranges in thickness between 4.9 and 7.5 feet, averaging 6 feet and the D Seam ranges in thickness between 8.5 and I0.5 feet, averaging 10 feet. Given these numbers, a subcrop slope of 4.60, and a regional dip of 40 for the coal seams, an average area of recharge of the subcrop for the E-Seam will be 230,715 square feet (5.30 acres), and for the D-Seam will be I58, 825 square feet (3.65 acres). According to information on pages 43 to 45 in the permit application, the E and D coal seams are aquifers and are recharged along subcrops by groundwater from the "Glacial-Alluvial Aquifer". The applicant states that the alluvial aquifer is fully saturated and recharged i by the streams (also irrigation systems). This would induce a constant pressure head on the subcrop area, and water recharging the coal seams through the coal subcrops will cause depletions from the overlying streams and irrigation systems. The actual depletions caused by inflows into the mines through the coal seams, however can not be determined without transmissivity (T) and storativity (S) values for the E and D coal seams and the "Glacial-Alluvial Aquifer'.'. Another component of groundwater flow into the mine will be through fractures connecting the mine working to the bedrock-alluvium contact. The greatest measured inflows into coal mines in the adjacent North Fork of the Gunnison coal field was observed to be from fracture and fault systems under perennial and ephemeral streams. Given the similar geology and the proximity to the North Fork of the Gunnison mining area, such condition may be expected at the Red Canyon No. 1 and No. 2 mines. The fracture systems beneath Ward and Williams Creek may contribute greater groundwater inflows to the mine than that which would be expected to flow through the coal seam itself. Mining activities beneath the "Glacial-Alluvial Aquifer" may introduce increased inflows. The mining activities may induce mine inflows through opening existing fractures or through fractures developed from subsidence over the mine working. Mine inflows may be induced directly from the alluvium to the mine or indirectly from the alluvium through overlying strata to the mine through these fractures. The sum of mine inflows will be a sum of all of the above mentioned types of in- flows. The total mine inflows may impact the flows in irrigation systems and flows in Ward and Williams Creeks through groundwater depletion. The groundwater depletion may reduce flows in irrigation systems and reduce subirrigation used to irrigate crops, thus impacting crop production. The flows in Ward and Williams Creeks may be depleted, since as the applicant states on page 44, the creeks are the primary source of recharge for the "Glacial-Alluvial Aquifer" and since the "Glacial-Alluo-ial Aquifer is very permeable.