REP50217 - Laserfiche WebLink

Home Browse Search

West Elk Mine 2004 Annual Hydrology Report 4 • Figure 2b. Snow Water Equivalent Data for McClure Pass . McClure Pass Snow Pack d 20 v c 15 d ~Aeerage Monthly SWE c 10 WYs 1981-2003 W ;; 5 _. . - Average Monthly 3 SWE W Y 2004 0 c 0 rn o~v ~,rp} ~~ J~c1 JatA aor PQ~. ~,~~ ,JCO ~~~~ A°y~ ~~ Oc~ .tz ~ ~a° Qe~s ~` ~~ P° ~ ~ ~ 5 2.2 Stream Flow Data • The North Fork of the Gunnison River (North Fork) and Minnesota Creek aze the major drainages in the Project area. The U.S. Geological Survey (USGS) maintains stream gaging stations on both of these perennial streams. Flow in these watersheds is dominated by snowmelt from upland areas. Flows in WY 2004 in both watersheds was below the historical average, as the drought conditions prevailing over the region for the past few years lessened, but did not completely abate. Average daily flows for the North Fork by month for the WY 2004 ranged from 50 percent of historical averages (1934-2004) in October 2003 to approximately 200 percent in March (Appendix A). March 2004 and August 2004 were the only months in WY 2004 with flows higher than the average historical flows. The average daily flow for WY 2004 was 68 percent (312 cubic feet per second (cfs)) of the historical daily average (455 cfs) for the years 1934 through 2004. The peak flow in the North Fork was 2,540 cfs on May 13, 2004. A summary of the stream flow data for the North Fork is graphically presented in Figure 3a. Minnesota Creek flows in WY 2004 were also below the historical average based on data From 1937 through 1947 and 1985 through 2003. The average monthly flows for WY 2004, compared to the historical average, ranged from 48 percent in May 2004 to 98 percent in March 2004. The average daily flow for WY 2004 was 59.52 percent (13.1 cfs) of the historical daily average (22 . cfs) for the period of record. The peak flow in WY 2004 for Minnesota Creek was 59 cfs on June Augus[ 2005 HydroGeo, Inc.