Conceptual model of the uppermost principal aquifer systems in the Williston and Powder River structural basins, United States and Canada

Long, Andrew J.; Aurand, K.; Bednar, J. M.; Davis, Kyle W.; McKaskey, Jonathan D.R.G.; Thamke, Joanna N.

doi:10.3133/sir20145055

Cited by 3 publications

(4 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For flow‐path lengths of 50 to 100 km and median 14 C ages of 4000 to 5400 years, tracer‐based horizontal groundwater velocities would be about 10 to 25 m/y. These velocities compare favorably with velocities (0.4 to 88 m/year) calculated from horizontal hydraulic conductivity and hydraulic gradient data for the upper Fort Union Formation (Long et al ), and assuming porosities ranging from 0.1 to 0.3. If the tracer‐based horizontal velocities are generally representative of the flow system then subsurface chemical leaks related to recent (˜2003) energy‐development activity, if present in groundwater, would still be less than 0.5 km from their source.…”

Section: Resultssupporting

confidence: 70%

“…Groundwater flow in the upper Fort Union Formation is mostly characterized by local‐ to intermediate‐scale flow systems controlled by local topography (Armstrong ; Smith et al ; Thamke et al ; Long et al ). The Missouri, Yellowstone, and other major river valleys are regional discharge zones for the upper Fort Union and Fox Hills‐Hell Creek Formations (Long et al ). Confined and unconfined conditions are present in the flow system.…”

Section: Description Of Study Areamentioning

confidence: 99%

“…The Fox Hills, Hell Creek, and upper Fort Union Formations are sources of water for domestic, public, and stock use in the study area. Of these bedrock systems, the largest water withdrawals are from the upper Fort Union Formation (Long et al ). The glacial aquifer system has larger water withdrawals than the underlying bedrock aquifers, but the glacial aquifer system generally is only present north of the Missouri River.…”

Section: Description Of Study Areamentioning

confidence: 99%

“…The analysis is primarily based on groundwater samples collected in 2013 from 30 domestic wells screened in the Tertiary upper Fort Union Formation. This study is one component of a USGS investigation of groundwater availability in the Williston and Powder River Basins that also includes development of hydrogeologic frameworks, water budgets, and conceptual and numerical models of groundwater flow for the two uppermost bedrock aquifer systems in the basins (U.S. Geological Survey ; Thamke et al ; Long et al ).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Quality and Age of Shallow Groundwater in the Bakken Formation Production Area, Williston Basin, Montana and North Dakota

McMahon¹,

Caldwell

Galloway

et al. 2014

Groundwater

View full text Add to dashboard Cite

The quality and age of shallow groundwater in the Bakken Formation production area were characterized using data from 30 randomly distributed domestic wells screened in the upper Fort Union Formation. Comparison of inorganic and organic chemical concentrations to health based drinking-water standards, correlation analysis of concentrations with oil and gas well locations, and isotopic data give no indication that energy-development activities affected groundwater quality. It is important, however, to consider these results in the context of groundwater age. Most samples were recharged before the early 1950s and had 14C ages ranging from <1000 to >30,000 years. Thus, domestic wells may not be as well suited for detecting contamination associated with recent surface spills as shallower wells screened near the water table. Old groundwater could be contaminated directly by recent subsurface leaks from imperfectly cemented oil and gas wells, but horizontal groundwater velocities calculated from 14C ages imply that the contaminants would still be less than 0.5 km from their source. For the wells sampled in this study, the median distance to the nearest oil and gas well was 4.6 km. Because of the slow velocities, a long-term commitment to groundwater monitoring in the upper Fort Union Formation is needed to assess the effects of energy development on groundwater quality. In conjunction with that effort, monitoring could be done closer to energy-development activities to increase the likelihood of early detection of groundwater contamination if it did occur.

show abstract

Section: Resultssupporting

confidence: 70%

Section: Description Of Study Areamentioning

confidence: 99%

Section: Description Of Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations