Physical Sciences and Mathematics Commons^™

Estimating Groundwater Discharge In The Oligohaline Ecotone Of The Everglades Using Temperature As A Tracer And Variable-Density Groundwater Models, Victora Spence

USF Tampa Graduate Theses and Dissertations

Recent research suggests that brackish, marine-derived groundwater up-wells in the oligohaline ecotone of the coastal Everglades, bringing with it phosphorus to an otherwise phosphorus-poor environment. The purpose of this study is to estimate the rates and timing of the groundwater discharge by using variable-density groundwater models constructed, calibrated, and validated with field measurements of hydraulic head and surface and subsurface temperature. Modeled groundwater discharge rates ranged from 5.4E-04 mm/day in August to -1.3E-03 mm/day in June for Shark Slough and 4.8E-01 mm/day in June to -1.4E-01 mm/day in January for Taylor Slough, where positive values imply groundwater discharge and negative …

Modeling Direct Runoff Hydrographs With The Surge Function, Denis Voytenko

USF Tampa Graduate Theses and Dissertations

A surge function is a mathematical function of the form f(x)=ax^pe^-bx. We simplify the surge function by holding p constant at 1 and investigate the simplified form as a potential model to represent the full peak of a stream discharge hydrograph. The previously studied Weibull and gamma distributions are included for comparison. We develop an analysis algorithm which produces the best-fit parameters for every peak for each model function, and we process the data with a MATLAB script that uses spectral analysis to filter year-long, 15-minute, stream-discharge data sets. The filtering is necessary to locate the …

Seasonal Changes In The Sinking Particulate Flux And In The Nitrogen Cycle Within The Euphotic And Twilight Zones Of The Cariaco Basin, Venezuela, Enrique Montes-Herrera

USF Tampa Graduate Theses and Dissertations

This study explored the effects of seasonal variability on the geochemistry of sinking pthesiss and on the nitrogen cycle of the Cariaco Basin. Pthesis fluxes were measured at the base of the euphotic zone (the depth of 1% of photosynthetically active radiation - PAR) with drifting sediment traps during months of upwelling and non-upwelling regimes from March 2007 to November 2009. Flux estimates were analyzed in the context of seasonal variations in sea surface temperature, primary productivity, and chlorophyll a concentrations using data generated by the CARIACO Time-series Program as well as satellite data. Additionally, nine years (1996-2000 and 2004-2007) …

Stratigraphy And Petroleum Production Potential Of The Spearfish Formation In North Central North Dakota, Nnaemeka C. Anyanwu

Theses and Dissertations

The Spearfish oil play is unconventional requiring the use of horizontal wells that are fracture stimulated to deliver economic flow rates. However, fraccing into the underlying water has been a source of significant production problems for operators. The key to developing the area is to keep the individual fracs large enough to stimulate the tight Spearfish sands but not to let them propagate into the underlying water zone.

The Spearfish Formation of the Black Hills has been traced into the subsurface of the Williston Basin in western North Dakota from bore holes at the northern margin of the outcrop area …

Identifying Potential Geothermal Resources From Co-Produced Fluids Using Existing Data From Drilling Logs : Williston, North Dakota, Anna M. Crowell

Theses and Dissertations

With the current need for technology that will allow for environmentally-friendly power generation, geothermal power has become an attractive resource given its low environmental impact and potential cost savings. One specific resource is co-produced water from oil wells that are not currently producing, but can yield formation waters that are both high enough in temperature and fluid volume to operate the turbines of binary geothermal power systems. The data required to identify sites, i.e. bottom-hole temperatures (BHT), latitude, longitude, total depth of hole (TD) in meters, the identification number, and the amount of water produced in gallons, can be mined …

Using Temperature Profiles To Investigate The Hyporheic Zone In An Agricultural Drainage Ditch, Richard A. Suggs

Theses and Dissertations

During the last three decades, there has been much research on ground water/surface water interaction and hyporheic zone processes in natural rivers and streams. Research into natural systems has revealed significant ground water/surface water interaction and a complex variability that depends primarily on surface conditions, subsurface composition, and seasonal influences. Hyporheic zone interaction is an important factor contributing to water quality of both surface water and ground water systems.

This research expands on the concept of using heat transport, as revealed by temperature variation, as an analogue for water movement within a surface water/ground water system to include the man-made …

Geomechanical Stability Analysis For Co2 Sequestration In Carbonate Formation, Xue J. Zhou

Theses and Dissertations

Geomechanical analysis is one of the fundamental pillars to build up the confidence of geological sequestration of CO2. Large scale CO2 sequestration in deep carbonate formation is a complicated geological process, which will non-reversibly transform the presumed equivalent and stable status of a sedimentary basin that formed over millions of years: chemically, hydraulically, geothermally, and geomechanically. In this dissertation, thermoporoelasticity guides the theoretical establishment of a conservative baseline for the geomechanical stability analysis of CO2 sequestration.

Extensive laboratory tests, including CO2 flooding tests, permeability tests, uniaxial and triaxial tests, Brazilian tensile strength tests, poroelasticity tests, point load tests, and fracture …