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PAGE 2 Along much of its outcrop reach in Colorado, Fruitland- Pictured Cliffs strata dip steeply southward towards the central portion of the San Juan Basin. Within the Fruitland Formation, porosity and permeability are greatest within the cleats of the coal seams. In addition to the coal seam permeability, fractures in the shales and sandstones that are adjacent to the coal seams are believed to provide local path- ways for ground water. Perme- abilities within the Fruitland - Pictured Cliffs aquifer are low, but greatly exceed those of overlying and underlying shale. Several streams cross the outcrop of the Fruitland Formation, including the Animas River, the Florida River, the Los Pinos River and the Piedra River. Alluvial deposits associated with these streams, and enhanced permeabil- ity of the Fruitland along the outcrop, support the occurrence of recharge along the outcrop and a shallow flow system from re- charge areas to the streams. SSPA was directed to apply the Glover - Balmer analytical method and also to comment at the conclusion of the analysis on method utility and limitations. Given the geologic configuration of the basin and the fluid with- drawal characteristics, the ques- tion was also posed as to whether this methodology, given its simplicity, could be reasonably applied to assess the general magnitude of stream depletion within a regulatory framework. Using the optimized values of transmissivity and storativity obtained from the parameter estimation analysis, the Glover analysis was applied to CBM wells within the Colorado portion of the San Juan Basin to identify the area where stream depletions exceed one -tenth of one percent of pumping within 100 years, and to quantify current and future depletions at the streams /outcrop. The method was not applied to the highly productive Fairway region where the Fruitland - Pictured Cliffs aquifer may not be water saturated. To estimate deple- tion in this area, a different method- ology would be required. The area where stream depletions exceed one- tenth of one percent of pumping within 100 years generally includes the area within about 10 miles of the outcrop (Figure 1). It is recognized that most CBM wells have a produc- tion life significantly less than 100 years, a factor that is expected to be given some consideration in regula- tion, should the CBM - produced water be put to beneficial use. To estimate the current magnitude of depletions, the Glover analysis was run using records of monthly water production rates to solve for basin- STREAMLINES wide depletions at the Fruitland outcrop /stream location. The com- posite rate of depletion for all Colo- rado wells was calculated at 156 acre - feet per year as of August 2005 (Figure 2). Various projections of future impacts were made, consider- ing a continuation of historical pumping until the end of production cycles, additional infill drilling, and additional infill drilling excluding drilling in a buffer zone within 1.5 miles of the outcrop. These projec- tions provide a general indication of the degree of stream/outcrop deple- tions occurring or likely to occur, from CBM- produced water. The results of this study indicate that depletion estimates are relatively low compared to flows in the rivers. The combined mean yearly base flows for the Animas, Florida and Pine Rivers average nearly 227,000 acre -feet per year. Even though the current amount of depletion estimated by this study occurs year- round, the amount of depletion that occurs during a time of surface water administration (i.e., -High ��Mfi%fty . A ; .. . f Figure 1. Delineation of area with 1000 -year stream depletion exceeding 0.1% of pumping