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show flow in Meehan Draw peaks at about 2.65 cfs and averages about 0.55 cfs, Glasier <br />Draw flow peaks at about 0.8 cfs and Nygren Draw flow peaks at about 1.5 cfs and <br />averages about 0.3 cfs . Tuttle draw flows (downstream of confluence with Nygren <br />Draw) with a peak of 9.35 cfs (thunderstorm) and an average of about 2.0 cfs. The <br />average flow (immediately downstream from the permit) is about 0.9 cfs in Coal Creek <br />Canyon. The peak flows occur during the later part of the irrigation season for the <br />irrigation water return drainages in contrast to the San Miguel River with lower flows <br />during the latter part of irrigation seasons because snowmelt has diminished and water is <br />being diverted for irrigation. <br />Surface Water Quality. At times of high flow in the San Miguel River, generated <br />largely by snowmelt runoff from the upland areas underlain by volcanic rocks, the water <br />is of the calcium bicarbonate sulfate type. During low flow, the water contains less <br />bicarbonate and greater amounts of calcium and sulfate. As flow progresses downstream, <br />the water quality features higher percentages of magnesium, potassium, sulfate and <br />chloride. Generally, Total Dissolved Solids (TDS) varies inversely with discharge, and <br />also increases in the downstream direction. Historic water quality samples taken at <br />Naturita, Colorado indicate that the San Miguel River has a weighted average TDS of <br />316 ppm and a pH of 8.0 and higher. Specific conductance ranges between 318 and 730 <br />umhos, and the mean Sodium Adsorption Ratio (SAR) is about 0.7. <br />The 2 " Park Lateral has relatively low conductivity averaging about 314 umhos /cm and a <br />pH of about 8.5, of a calcium bicarbonate type reflective of the snowmelt water of the <br />San Miguel River. Glasier Draw has a lower pH of about 7.3 and a conductivity of 1641 <br />umhos /cm whereas Meehan Draw has a pH of 7.0 and a conductivity of 1286 umhos /cm. <br />Both Glasier and Meehan draws have higher calcium and sulfate contents than does the <br />2 ❑d Park Lateral showing the deterioration effects of leaching of solids by the irrigation <br />water. Nygren Draw has an average conductivity of about 887 umhos /cm and a pH of <br />about 8.2. Tuttle Draw has an average conductivity of about 1860 umhos /cm and a pH of <br />about 8 2 immediately below the confluence with Nygren Draw. <br />Regional Ground Water. Topography, lithology and structural trends each play a <br />principal role in controlling the quality, quantity and flow characteristics of the regional <br />ground water regime in the direct vicinity of WFC's New Horizon North (NHN) Mine <br />Area. As seen in the geology discussion (Section 2.04.6) of the permit application, the <br />geology of this region is complex. Consequently, the ground water system is difficult to <br />interpret. Understanding the affect the NHN Mine may have on the local and regional <br />ground water supply relies on understanding the regional and local ground water systems. <br />Topography. Topography is the principal element governing shallow aquifers (100 feet) <br />in the Canyon Land Section of the Colorado Plateau Physiographic Province. <br />Topographic highs act as recharge areas, and lows along streams serve as discharge areas <br />during periods of high water table. In alluvial and other unconsolidated material, ground <br />water moves from high topography to low. This also appears to be the case for the <br />unconfined portions of sandstones in the Dakota and Burro Canyon formations. <br />Section 2.04.5 Page 5 April 2011 <br />