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alluvial aquifers. <br /> Movement of groundwater in the alluvial aquifers is controlled by the characteristics of the <br /> stream drainages within which they occur, including the stream gradient as well as the width, <br /> thickness and hydraulic conductivity of the alluvial deposits. Recharge to alluvial aquifers <br /> occurs as infiltration from snowmelt and precipitation and as seepage losses from streams. <br /> Baseline groundwater quality studies for the Yoast Mine included the alluvial aquifers, the <br /> Middle Coal Group, and the Trout Creek Sandstone. Table 2 below, summarizes baseline data <br /> for pH, 504, and total dissolved solids (TDS) for the units mentioned above. <br /> Table 2: Baseline Water Quality Data <br /> Aquifer pg SO4 (mg/l.) TDS(mg/1) <br /> Annand Draw Alluvium 7.5 632(avg.) 816-1802 <br /> Grassy Creek Alluvium 7.02-7.42 167-2517 546-4030 <br /> Sage Creek Alluvium 6.7-8.3 <539 344-1146 <br /> Lennox Coal 6.7-7.0 303-480 920-1200 <br /> Lennox Overburden 6.8-6.9 1790-4157 2030-6432 <br /> Wadge Overburden 6.5-8.8 99-1737 549-3052 <br /> Wadge Coal >12 <500 234-1232 <br /> Wadge Underburden 6.9-7.0 14-696 996-1550 <br /> Wolf Creek Coal 6.9-8.5 346-416 904-988 <br /> Trout Creek Sandstone 7.2-8.25 412 871 <br /> Climate <br /> The average annual precipitation of the town of Hayden, Colorado, 8.5 miles northwest of the <br /> mine site, is approximately 15.9 inches. Precipitation for Hayden is relatively uniform <br /> throughout the year. The mean annual temperature is 42°F, with an average maximum and <br /> minimum temperature of 66°F and 17°F, respectively. The predominant wind direction at the <br /> Seneca IIW Mine, located west of the Yoast Mine, is from the east southeast. This direction is <br /> in conformance with the topography of the site, and therefore may not be indicative of expected <br /> wind directions at the Yoast Mine. The average wind speed at the Seneca IIW Mine is 3.5 knots, <br /> with an average maximum of 15.4 knots, and an average minimum of 17 knots. <br /> Ve etg ation <br /> Five major vegetation community types occur within the Yoast permit area. These major <br /> vegetation community types are: <br /> o Mountain Brush <br /> o Sagebrush <br /> o Aspen <br /> o Steep Mountain Brush <br /> o Western Wheatgrass/Alkali Sagebrush. <br /> Additional community types occur within the permit area, but are considerably smaller <br /> acreages. These additional vegetation types include: <br /> o Upland and sub-irrigated improved pasture Mesic drainage <br /> 8 <br />