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Facts about CBM and water

Facts about CBM and water. Extraction of CBM requires withdrawal of water from coal seams containing methane. Projections call for disposal or management of one quarter million acre-feet of product water annually in the Powder River Basin.

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Facts about CBM and water

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  1. Facts about CBM and water • Extraction of CBM requires withdrawal of water from coal seams containing methane. • Projections call for disposal or management of one quarter million acre-feet of product water annually in the Powder River Basin. • Common signature of CBM product water is salinity, sodicity, ammonia, bicarb, minor other constituents. NWF 3/1/03, Blgs

  2. EPA Region 8 Towns Powder River Basin Coal strip mines Areas prospective for CBM exploitation Areas of current CBM development Axis of Powder River Basin Miles City Forsyth North Dakota South Dakota Powder Yellowstone River Tongue Colstrip Ashland Broadus Montana Wyoming Decker Sheridan Belle Fourche River Gillette North Platte River Casper Courtesy of John Wheaton, MBMG

  3. How much water? • Average annual flow of Tongue River is ~ 320,000 acre feet • Projected CBM product water volume is ~ 250,000 acre feet/year NWF 3/1/03, Blgs

  4. Water Quantity and Quality Will Dictate Water Management Options • Discharge to surface streams • Ephemeral v. perennial • Loosing v. gaining • Surface discharge, spreading, irrigation • Discharge to impoundments • Evaporation v. infiltration • Long term recharge v. abandonment • Re-Injection – shallow v. deep NWF 3/1/03, Blgs

  5. Options for Beneficial Use • Livestock – watering, dispersals, enhancement of forage utilization • Fish and wildlife –flow augmentation and salinity modification-quality dependent • Industrial – dust, fire, extraction, new uses • Irrigation and added rainfall effects-??? • Aquifer recharge, water storage • Recreation • Augmentation of domestic supplies – wells NWF 3/1/03, Blgs

  6. Generalizations about CBM Product Water Quality • Range in TDS of PRB CBM product water is 270-2,730 ppm, average is 740 ppm; median is 838 ppm • Drinking water standard is 500 ppm • Livestock water standard is 5,000-10,000 ppm • SAR range of 5-68.7, median 8.8; threshold = 12 • EC (SP) ranges from < 0.5 to > 10 dS/m across basin; threshold = 3.0 dS/m NWF 3/1/03, Blgs

  7. The most looked-at water quality parameters NWF 3/1/03, Blgs

  8. The most looked-at water quality parameters NWF 3/1/03, Blgs

  9. What is saline water and what are the common problems or difficulties with the use of saline water for irrigation? • Saline water has a relatively high concentration of dissolved salts (sodium, calcium, magnesium, sulfates, chlorides, bicarbonates). • Plant growth becomes a problem as salts accumulate in the root zone high enough to negatively affect plant growth. • Excess soluble salts in the root zone restrict plant roots from withdrawing water from the surrounding soil. NWF 3/1/03, Blgs

  10. Crop Tolerance to Saline Water NWF 3/1/03, Blgs

  11. What is sodic water and what are the common difficulties with the use of sodic water for irrigation? • The sodicity of water is expressed as the Sodium Adsorption Ratio (SAR) which is: • The relative amount of sodium compared to calcium and magnesium; SAR greater than 12. • Sodic water is not necessarily saline. • leads to poor drainage and crusting, which can affect establishment, growth and yield. • irrigation with sodic water on sandy soils does not cause crusting and poor drainage. However, if the water is saline-sodic, it may affect crop growth and yield. NWF 3/1/03, Blgs

  12. NWF 3/1/03, Blgs

  13. CBM product water in the Powder River Basin - knowns • Trend of increasing sodium adsorption ratio (SAR), electrical conductivity (EC) and total dissolved solids (TDS) progressing north and west through the basin (Rice et al., 2000). NWF 3/1/03, Blgs

  14. Additional knowns • Most wells in southern portion are within the irrigation standards; • Most wells in the northern section are above the limits for salinity and sodicity (Rice et al., 2002). • Soils are generally high in clays and can be saline-sodic. NWF 3/1/03, Blgs

  15. NWF 3/1/03, Blgs Courtesy of John Wheaton, MBMG

  16. Saline and sodic conditions promote new plant communities • Typically, encroachment by saline and sodic water promotes development of salt-tolerant, halophytic communities • Commonly occurring species include: • Prairie cordgrass Cattail • Baltic rushes American bullrush • Salt cedar Alkali grass NWF 3/1/03, Blgs

  17. NWF 3/1/03, Blgs

  18. NWF 3/1/03, Blgs

  19. Sensitive (EC < 2 dS/m, SAR 1.6 - 8 June/Service Berry Red Osier Dogwood Red Shoot Goose Berry Chokecherry Wild Plum Quaking Aspen Leafy Aster Red Raspberry Moderately Sensitive (EC 2-4 dS/m, SAR <8) Common Spikerush Field Horsetail Horsemint Sweet Medicine Sandbar Willow Snowberry Cattail Sweet Grass Saw Beak Sedge Stinging Nettle Western Yarrow Tolerance and/or sensitivity of culturally significant plant species on the Northern Cheyenne Reservation to salinity, sodicity, and flooding - NWF 3/1/03, Blgs

  20. Change in CBM water chemistry over a 9 day time period following discharge subject to evapoconcentration. Initial pH Final pH Initial EC Final EC Initial SAR Final SAR % Change EC % Change SAR WQ6 7.4 8.1 3.07 3.75 3.7 4.4 22.15 18.92 WQ7 7.7 8.4 3.36 4.01 12.5 18 19.35 44.00 WQ8 7.5 9.1 5.42 6.71 20.7 33.8 23.80 63.29 Average % Change 21.77 42.07 NWF 3/1/03, Blgs

  21. Change from outfall to irrigation • Aaron DeJoia • Cascade Earth Sciences NWF 3/1/03, Blgs

  22. NWF 3/1/03, Blgs

  23. NWF 3/1/03, Blgs

  24. Summary Sustainable CBM product water management requires rigorous monitoring and coordinated management • Essential requirements – • Soil, water, and plant baseline information • Amount and quality of CBM product water • Rigorous monitoring at all points • Coordinated water management with multiple strategies NWF 3/1/03, Blgs

  25. A Strategy for CBM product water management • Key elements to CBM product water management • Watershed based water management • Surface and ground water in concert • Maximize beneficial uses – infrequent water spreading • Maximize plant consumptive use – reducing water volumes with wetlands • Minimize deep drainage NWF 3/1/03, Blgs

  26. MSU Water Quality Web Site • http://waterquality.montana.edu/ NWF 3/1/03, Blgs

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