HR: 0800h
AN: H31D-0442    [Abstracts]
TI: Water Budget and Modeling of Stream Channel Infiltration of Coalbed Methane Co-Produced Water at a Storage Impoundment Site, Powder River Basin, Wyoming
AU: Payne, A A
EM: apayne@uwyo.edu
AF: University of Wyoming, Department of Geology & Geophysics, 1000 E University Avenue, Dept. 3006, Laramie, WY 82071 United States
AU: * Saffer, D M
EM: dsaffer@uwyo.edu
AF: University of Wyoming, Department of Geology & Geophysics, 1000 E University Avenue, Dept. 3006, Laramie, WY 82071 United States
AB: Rapid coalbed methane (CBM) development in the Powder River Basin, Wyoming, has resulted in a dramatic increase in the number of producing wells, with as many as 40,000 new wells projected to drilled during the next decade. CBM development involves the co-production of large volumes of coalbed water, which is most commonly discharged to impoundments. Little is known about the potentially significant effects that this co-produced water may have on shallow aquifers and water budgets. Since many of the impoundments in the Powder River Basin are in-channel and supplement surface water flow, it is important to understand what factors influence stream channel infiltration. Modeling of cross-sectional infiltration in a stream channel was undertaken using the U. S. Geological Survey's SUTRA finite-element code, simulating fluid movement from the stream channel, through the unsaturated zone, and into the shallow aquifer. Soil type, saturated hydraulic conductivity, and degree of anisotropy within the soil layer were analyzed to better understand the effects that each have on channel infiltration. At a small study site containing two in-channel infiltration impoundments in the Beaver Creek drainage (a tributary to the Powder River), water budgets have been determined from late July, 2003 to the present (excluding the winter months). Calculated infiltration rates of 0.04 cfs/mile in a 0.8 m wide stream channel compared well with modeled regional soils. Slug tests were utilized to determine aquifer properties in the underlying alluvium/weathered bedrock. A two-layer SUTRA model is presented representing the upper soil layer and underlying alluvium/weathered bedrock and compared to observed changes in groundwater levels in the stream sections affected by introduced CBM water.
DE: 1803 Anthropogenic effects
DE: 1829 Groundwater hydrology
DE: 1836 Hydrologic budget (1655)
DE: 1860 Runoff and streamflow
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting