Physical Sciences and Mathematics Commons^™

Evaluating The Feasibility Of Using Strain Measured During Sinusoidal Rate Pumping Tests To Characterize An Aquifer, Riley Blais

All Theses

Pumping tests with sinusoidal variation in pumping rate have been proposed as a method for improving aquifer characterization. These tests can interrogate a larger aquifer volume than slug tests and they can be more sensitive to small variations in drawdown. Current methods of using sinusoidal variations of rate are based on measuring pressure signals from the reservoir or aquifer, which requires access to monitoring wells. An alternative approach has been developed that measures the strain in the vadose zone instead of pressure in the reservoir. An instrument has been developed at Clemson University that can measure small strains using optical …

Evaluating The Sensitivity Of Crustal Deformation To Bedrock Hydrology In A Mountain Watershed, Brett J. Oliver

Graduate Student Theses, Dissertations, & Professional Papers

We evaluate the sensitivity of Earth's elastic deformation to groundwater hydraulic diffusivity using coupled groundwater and elastic deformation models. Seasonal changes in terrestrial water storage cause deformation to the Earth’s crust and deeper interior that is within the observational capacity of GPS instruments. We couple finite difference groundwater simulations with geodetic forward models of crustal displacement to investigate the ability of geodetic deformation to constrain bedrock hydrologic properties. We use MODFLOW-2005 to simulate seasonal changes in groundwater flow and storage, and then use the LoadDef elastic deformation model to forward model surface displacement caused by the change in terrestrial water …

Hydrogeologic Investigation Of A Covered Karst Terrain, Joseph Peter Honings

LSU Doctoral Dissertations

Increasing demand for water for agricultural use within the Dougherty Plain of the Southeastern United States has depleted surface water bodies. In karstic landscapes, such as the Dougherty Plain in southwest Georgia where the linkages between surface and ground waters are close, there is a need to understand the physical characteristics of the subsurface that allow these close linkages. Having a better understanding of the subsurface characteristics will aid numerical modeling efforts that underpin policy decisions and economic analyses. Two common features on this karstic landscape are draws and geographically isolated wetlands. Using LiDAR, aerial imagery, and ground-penetrating radar, this …

Imaging Wetland Hydrogeophysics: Applications Of Critical Zone Hydrogeophysics To Better Understand Hydrogeologic Conditions In Coastal And Inland Wetlands And Waters, Christine Marie Downs

USF Tampa Graduate Theses and Dissertations

This dissertation consists of three projects utilizing electric and electromagnetic (EM) methods to better understand critical-zone hydrogeologic conditions in select Florida wetlands and waters.

First, a time-lapse electrical resistivity (ER) survey was conducted in section of mangrove forest on a barrier island in southeast Florida to image changes in pore-water salinity in the root zone. ER data show the most variability in the root zone over a 24-hour period, and, generally, the ground is more resistive during the day than overnight.

Second, a suite of three-dimensional forward models, based on varying lateral boundaries and conductivities typical of a coastal wetland, …