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Alountain Coal Compan}~ 2000 Annual Hydrolog}' Report Wesl Eik Mine extent to which the weather deviated from normal. For precipitation data, C/imato/ogica! Da[o • jor Co%racJo, published by the National Oceanic and Atmospheric Administration, were used. For the snow data, snow station data from the Natural Resources Conservation Service SNOTEL information database was used. Total precipitation measured at the Paonia 1 SW station for WY00 was 68% of normal -defined by the 30-year average (1961-1990). For WY00, snowpack was 58% of average at the Overland Reservoir snow station and 60% of the average at the McClure Pass Station. Figures 1 through 3 show the monthly distribution of the precipitation measured at each of these three stations. Hydrological Data in addition to the climatological data, a water yeaz can be characterized by streamflow. The major drainage basins in the vicinity of the West Elk Mine are the North Fork of the Gunnison River (North Fork) and Minnesota Creek. The U.S. Geological Survey (USGS) has gaging stations on both of these streams. Both of these watersheds are large and the annual flow is dominated by snowmelt from the higher elevations. Paonia Reservoir also affects the North Fork flow regime. To facilitate comparison of the WY00 streamflow data to the period of record, Figures 4 and 5 were prepared. These graphs indicate that flow in both the North Fork drainage and in Minnesota Creek were well below average in WY00, primarily due to the below average snowpack noted above. Annual runoff in the Norh Fork drainage was 70% of the long-term average, and in the Minnesota Creek drainage, runoff was only 41% of the long-term average. For WY00, an instantaneous peak discharge of 48 cfs was recorded on Minnesota Creek on May 24 and an instantaneous peak discharge of 2,130 cfs was recorded on the North Fork on May 8. 83l -03?.550 Page 2 Wrrghl Wafer Engineers