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Isotopic Tracers As Evidence Of Denitrification In The Karlsruhe Aquifer, Eben J. Spencer

Theses and Dissertations

The Karlsruhe Aquifer of north-central North Dakota has experienced considerable nitrate contamination sparking an investigation by the North Dakota State Water Commission. Certain portions of the aquifer have experienced nitrate-N concentrations of up to seven times the drinking water standard. Although contamination is evident it is possible the NO₃¯ is naturally being eliminated by denitrification, whereby bacteria reduce NO₃¯ to nitrogen gas. Evidence of denitrification may be illustrated by accelerated reduction of NO₃¯ relative to the conservative tracer Cl¯ coupled with an increase in the heavy isotopes of 15N and 18O within the NO₃¯ ion. Such an increase is not …

Assessing Recharge And Discharge Across The Prairie Pothole Landscape: Application Of Spatial Hydrological Data And Statistical Analysis In A Groundwater Flow Model, Christopher D. Laveau

Theses and Dissertations

Quantifying the spatial and temporal dynamics between groundwater recharge, discharge, and wetlands is a necessary step to develop effective water management strategies. Wetlands in the northern Great Plains play a role in flood control, water supply, and regional ecology. The water budget of a wetland in the northern prairies is often an unequal balance between moisture input and output in which the permanence of a wetland depends on its groundwater budget. Identifying and quantifying groundwater recharge and discharge zones has applications in predicting the spatial and temporal distribution of wetlands.

The current work involved the application of a groundwater model …

Geomechanics Applied To Reservoir Development In The Coso Geothermal Field, Andrew J. Nygren

Theses and Dissertations

The Coso geothermal field is located approximately 220 kilometers north of Los Angeles, CA. In 2002, a project began to develop the east flank of the Coso geothermal field into an enhanced geothermal system (EGS); in such a system water is injected via injection well(s) into hot dry basement rock through naturally occurring or stimulated fractures. The injected water gathers heat from the reservoir rock before being extracted for direct use or energy production. To develop such a reservoir, adequate understanding of the reservoir geomechanics is necessary. This thesis investigates the state of stress and rock fractures, the existing permeable …

Reevaluation Of Species Concepts Of Uppermost Cretaceous Unionidae (Mollusca: Bivalvia) : Hell Creek Formation, Montana, U.S.A., Marron J. Bingle

Theses and Dissertations

Species are the basic units of life relative to taxonomy, and a practical definition of species is imperative to paleontology in order to promote reproducible, unambiguous criteria for accurately interpreting past species relationships. The need for a well-defined rubric for identifying species is evident in the freshwater mussel assemblage (Family Unionidae) in the Hell Creek Formation. The Hell Creek Formation unionid species were first described by Whitfield in 1903 and 1907. His descriptions were often based on differences of a single trait. In 197 6, Russell reevaluated the original species descriptions, I but still based the classification of species on …

Regional Stratigraphy Of The Newcastle Formation (Lower Cretaceous) In Eastern Montana And Western North Dakota, Adam J. Ulishney

Theses and Dissertations

The Newcastle Formation (Lower Cretaceous) consists of sandstone with interbedded shale, siltstone, and mudstone facies. This work shows that the regional stratigraphy of the unit is detailed enough for the interpretation of its depositional history and environments in eastern Montana. This work also illustrates the possible lowstand position of the Western Interior Seaway along with probable source areas providing sediments into the study area.

A total of 3446 geophysical wireline logs were used to determine formation tops of the Greenhorn, Mowry, Newcastle, Skull Creek, and Inyan Kara Formations. The log character of the Newcastle Formation was also described for all …

Hydrology Of The Springs, Seeps, And Fens At The Nature Conservancy's Pigeon Point Preserve, Ransom County, North Dakota, Corey W. Askin

Theses and Dissertations

Pigeon Point lies along the Sheyenne River in the west-central part of the Sheyenne Delta Aquifer, southeastern North Dakota. Groundwater discharges along a north-facing bluff at Pigeon Point and forms springs, seeps, and fens 'hosting atypical boreal species. The Nature Conservancy owns 231 ha at Pigeon Point, a tract that also includes the largest and least disturbed spring-fed stream in the region as well as some of the finest riparian forest in the state. In response to possible future groundwater diversion, the objectives of this study are: 1) to characterize the Sheyenne Delta Aquifer up-gradient from Pigeon Point, 2) to …