Yampa - Sand Wash Coalbed Methane Production Depletive Effects on Water Resources Study_Scope of Work Expand

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1. Compile location and depth of production data for existing water wells within the basin; 2. Compare depths of completion for the water wells with coal-bearing stratigraphic intervals that are, or have the potential to be, intervals of CBM production; 3. Compare CBM water production rates associated with CBM development with water production rates from permitted water wells, providing sufficient data are available. 5. Relate Target CBM Intervals to Surface Water Systems The surface hydrology shall be characterized with respect to identification of the streams involved and the drainage basins associated with any such streams. The nature of the streams and their associated alluvial aquifers will be assessed with respect to flow conditions (perennial or intermittent), the nature, thickness and extent of the associated alluvial aquifer, the losing or gaining nature of the stream, and the alluvial water table. This work will also include identification of the administrative stream basins and whether or not these basins are considered by the Division of Water Resources as over- or under-appropriated. Discussion of whether any of the stream administration basins identified as under-appropriated might be reclassified as over- appropriated in the reasonable future is required. To carry out the depletion analyses, it is required that the stream-aquifer contact areas be accurately and thoroughly delineated. This work will also include determination as to whether any stream reaches may exhibit hydraulic break conditions. The work under this category will include assessments, at a minimum, of the following items: 1. Map surface drainage basins o Map primary watershed boundaries relative to the basin; o Identify perennial and intermittent stream segments. 2. Map stream-CBM target contact areas; 3. Evaluate potential pathways between CBM production and stream contact areas. 6. Characterize Water Quality of CBM Intervals, Local Aquifers, and Surface Water Water quality is a factor with respect to any current or future discharge to the stream system and with respect to the potential for utilizing water quality parameters, and total dissolved solids ("TDS") in particular, as an indicator of possible recharge to the target formations from surface waters. Accordingly, this study will include characterization of the CBM production water quality and the water quality of the local stream systems identified and ground water resource aquifers as being in contact with the target formations. The data will be assessed with respect to any similarities or differences and with respect to whether the data indicates a potential recharge interconnection between the two sources. The work under this category will include assessments, at a minimum, of the following items: 1. Characterize quality of CBM production water, particularly total dissolved solids (TDS) and major ion content; 2. Characterize water of local stream systems; 3. Characterize water of local aquifer systems. 7. Identify Data Insufficiencies and Devise Plan to Fill Critical Data Gaps CBM production in the Sand Wash Basin is in the early stages of development and ground-water usage is concentrated in areas of private land ownership in the eastern part of the basin. Accordingly, available aquifer data may be very limited in detail and geographic distribution. These data are valuable for both evaluating and modeling possible depletive effects from CBM development as well as establishing a bench mark against which future impacts can be measured. Assessments of CBM development impacts in the Raton and San Juan Basins were