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• 1.0 HYDROLOGIC MONITORING ACTIVITIES <tt::;:~~::-:;:~~:~.~:~>::.,:<:;:c:~::~-,.:::::::~~.;::~c:.:~;:~::::;a:.::>;,::::..:~:::;:s:a::;>.:~a~sr.W..,...ats:~x::^-:;>N:s~:::r:<:~~;:;;~:::::::;«:.•;::~:y:~:~:,:~.:::,:.:,::.r,::x.::;,;:;:~ :::::::::::::::: ~.: ,.. <.:.:..:,o.::r::;s.:.a~ 1.1 INTRODUCTION This 1995 Annual Hydrology Report covers the period from 1 October 1994 through 30 September 1995 (Water Year 1995). The hydrologic monitoring program for the West Elk Mine (Permit C-80-007) began in 1974 with the completion of several groundwater observation wells. This preliminary monitoring network was expanded consider- ably and in 1981, with the approval of the West Elk Mine Mining and Reclamation pian (M and R Plan), became the "ap- proved" hydrology monitoring program. The program was revised in 1984, 1487, 1989, 1993, and 1994. The 1984 and 1987 revisions were made to more efficiently monitor possible effecu from mining and provide data for furore permitting. The 1989 revision incorporated provisions for collecting "B" seam baseline data and monitoring for potential mining impacts in anticipation of the 1990 opening of the "B" Seam. Modifications in 1993 evolved in conjunction with the Jumbo Mountain expansion (PR-S). In response to Division adequacy review of the 1990, 1991, and 1992 AHRs, revision TR-71 was initiated in 1994 and approved in 1995. The provisions of TR 71 were fully implemented during WY 1993. Exhibit 1 (Map 34, Locations of Hydrologic Monitoring Stations at the West Elk Mine, Revision 4, 4/95). Surface water (streams and ponds}, springs, and groundwater are considered separately even though they may be intemvined. The report discusses the interrelationships that are significant or could be expected. 1.2 RIVERS, STREAMS, AND PONDS MONITORING A baseline characterizatio^ of North Fork water quality was performed to evaluate the potential changes in Noah Fork water quali- ty that could result from discharges at the West Elk Mine. Baseline characterization was performed downstream of the [[tine before the start of construction in August 1981. Data sources were the USGS stream gauging station on the North Fork near Somerset above the mine facilities, and the Mountain Coal Company's (MCC) water quality monitoring station on the North Fork below the mine. The MCC station is down- stream of the surface facilities area and downstream of all discharge points. Baseline data and analysis of these data are provided in the Mining and Reclamation Plan for the West Elk Mine and in the first annual hy- drology report. Sampling "seasons" or "windows" that provide for collection of samples on the rising limb of the hydrograph (April 3 to May 13), hydrograph peak (April 21 to June 26), and full low flow (July 10 to October 8), are reflected in the program. The locations of water monitoring stations (surface and groundwater) are indicated on .VUt-93 '_10/OSi13/9e(I:JBpm) MCC's WY 1995 surface water monitoring program is described in Table 1.2-1. Appendix A and Appendix B have preliminary flow data from the continuous recorders located at the USGS sites on Minnesota Creek downstream of the Dry 3 REVISED 0987/96