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. are approximately double those of well FBR-11-B. Lastly, well FBR-11-B exhibited a moderate sulfate concentration on April while none was detected in well FBR-2. Trout Creek Sandstone:During 1996, four Trout Creek Sandstone wells (001-83-106, OOI-83-107, FCM#2, and FBR-2-E) required monitoring for water levels and field pazameters on asemi-annual basis. An additional well (008-75-EFC) required an annual water level measurement. Wells 001-83-106, FCM#2, and FBR-2-E also required water quality sampling on a semi-annual basis. Well FCM#2 was replaced in the fall of 1995 by monitoring well 95M001. Semi-annual monitoring during 1996 occurred at well 95M001 in lieu of FCM#2. Field parameters at well 001-83-107 were not obtained during 1996 as [his well had formerly been pressurized and was constructed to remain sealed. Pressures during 1996 were reduced to the point that artesian flow from the well ceased. Though water level measurements were obtained, no opening large enough for a bailer was available to extract water for field parameter measurements. [n December, 1996, the well was modified to provide access for a bailer and field parameter measurements were obtained. An elevated pH was noted at this time (9.76) with conductivity and temperature readings normal. This data is provided on Table 13 and will be included in next year's AHR as well. Tables 12 through 16 provide summaries of the 1996 Water Year data collected at each site. Table 12a provides the period of record statistical summary of collected data at well 001- 83-106 with Tables 15a and l6a providing [he period of record statistical summaries of collected data at wells 95M001 and FBR-2-E. Figures 25 through 31 provide graphical representations of water levels and selected water quality parameters recorded at each site. • The potentiometric surface in the Trout Creek Sandstone is complicated by the continuous pumpin of well. 83-106 (Figure 25). The potentiometric surface trends prevalent in the Twentymile Sandstone and Wadge Overburden aquifers are not evident in the monitored Trout Creek wells. The previously monitored well 006-83- 48C routinely exhibited water levels in. the 7100 ft elevation range while replacement well FCM#2 returned levels around elevation 6520 during 1995. In the fall of 1995, well 95M001 was established in part to address the apparent discrepancy in water levels between wells 006-83-48C and FCM#2. Water levels returned from~uE11 95M001 confirm that levels recorded from well FCM#2 were accurate (Figure 27). Inflows from the Trout Creek Sandstone into the mine workings have not been encountered to date to account for the apparent lowering of the potentiometric surface in the Trout Creek formation as indicated by the water level data previously recorded for well 006-83-48C. Some dewatering of the aquifer does occur from the pumping of well 001-83-106 to supply the mine with domestic water. During 1996, the southernmost Trout Creek well (001-83-107 -Figure 26) exhibited lower water levels in the 6875 ft elevation range while the northernmost well (008-75-EFC -Figure 28) increased to around the 6620 ft elevation level. Well FBR-2-E (Figure 30) returned levels around 6730 ft elevation during 1996. With the exception of well 001-83-107, water levels in the Trout Creek were observed to be consistent with recently obtained measurements. Well 001-83-107 continued to show lower water levels than those typical prior to 1992. As previously noted, the water level in this well declined during 1996 to the point that artesian pressures no longer occur at this site. Well 001-83-106 remains drawn down presumably due to consistent • -4-