2013-07-02_REPORT - C1980007 (3)

Home Browse Search

West Elk Mine 2012 Annual Hydrology Report 2 2.0 HYDROLOGIC SUMMARY OF WATER YEAR 2012 During WY 2012, the total annual precipitation in the vicinity of the West Elk Mine was below average at the Paonia 1 SW (56306) meteorological station; slightly below average at the Overland Reservoir (59853/CO07K14S) SNOTEL station, and below average at the McClure Pass (59743/CO07K09S) meteorological and SNOTEL stations; compared to the historical (30 -year where available) total annual precipitation data (CCC, 2013; NRCS, 2013a; NRCS 2013b) (Figures 1 -3). During WY 2012, the snow water equivalent (SWE) data were well below the historical annual averages at the Overland Reservoir and McClure Pass stations (NRCS, 2013c), resulting in below average stream flows in the permit and surrounding areas (Figures 4 and 5). 2.1 Climatological Data Precipitation and snow water equivalent (SWE) data for the permit and surrounding area for WY 2012 were derived from the following meteorological and SNOTEL stations: Paonia 1SW (56306), McClure Pass (59743/CO07K09S), and Overland Reservoir (59853/CO07K14S) (CCC, 2013; NRCS, 2013a; NRCS 2013b; NRCS, 2013c). Figures 1, 2, and 3 depict the WY 2012 total monthly precipitation data compared to the 30 -year historical average monthly precipitation data (WY 1981 -2010) for Paonia 1SW and McClure Pass, and the 22 -year (WY 1990 -2011) historical average for Overland Reservoir. The total accumulated annual precipitation in WY 2012 was 11.78 inches at Paonia 1SW, 23.8 inches at McClure Pass, and 21.3 inches at Overland Reservoir (CCC, 2013; NRCS, 2013a; NRCS 2013b). This corresponds to 78 %, 72% and 98 %, respectively, of the historical average total accumulated annual precipitation values recorded at Paonia 1SW (15.1 inches), McClure Pass (33.2 inches), and Overland Reservoir (21.7 inches) (CCC, 2013; NRCS, 2013a; NRCS 2013b). June 2013 HydroGeo, Inc.