Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010. / Committee Member: Pavlostathis, Spyros; Committee Member: Spain, Jim; Committee Member: Tezel, Ulas. Part of the SMARTech Electronic Thesis and Dissertation Collection.

This thesis examines the history of groundwater management through the development of groundwater conservation districts in Texas. Political, economic, ideological, and scientific understandings of groundwater and its regulation varied across the state, as did the natural resource types and quantities, which created a diverse and complicated position for lawmakers and landowners. Groundwater was consistently interpreted as a private property right and case law protected unrestricted use for the majority of the twentieth-century even as groundwater resources crossed property and political boundaries, and water tables declined particularly during the second-half of the century. The case study of the Brazos Valley Groundwater Conservation District describes the complicated history of groundwater in Texas as the state attempted to balance natural resource legislation and private property rights and illuminate groundwater’s importance for the future.

published_or_final_version / Applied Geosciences / Master / Master of Science

published_or_final_version / Applied Geosciences / Master / Master of Science

No description available.

No description available.

The goal of this work is to investigate the influence of overburden cover on controlling recharge to a bedrock aquifer, specifically focusing on rapid recharge events. Rapid recharge events have been observed in a fractured rock site in eastern Ontario and fractured rock sites around the world. The mechanisms that cause these events are poorly understood. At a field site near Perth, Ontario, measurements of hydraulic head were obtained in the spring and summer of 2012 using 18 different monitoring wells. Rainfall and weather data were also collected. Infiltration experiments were performed in the summer period using a 10 m by 10 m rainfall simulator. A ground penetrating radar (GPR) survey was conducted around a piezometer to determine depth to bedrock. Permeameter tests were performed in the overburden layer. A piezometer which responds rapidly to rainfall was identified and field measurements and observations were used to numerically model the piezometer on an outcrop. Three-dimensional numerical simulations reproduced the response in the piezometer for both short (24 hour) and long (one month) timescales. An equivalent porous media (EPM) approach was taken to numerically model fractured rock. The numerical simulations for a month-long period required that evapotranspiration was accounted for and this was achieved by limiting applied rainfall to the area above the outcrop in the model. Numerical simulations were also used to determine what parameters have the greatest effect on controlling rapid recharge. Based on this study it was concluded that large magnitude head rises recorded in this piezometer are a result of recharge to the shallow aquifer. Hydraulic head rises rapidly because of transmissive vertical fractures connecting the low specific yield rock to the surface. A thin layer of overburden (0.4 m) can completely eliminate response in the well especially during times when evapotranspiration is high. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-10-15 14:29:12.225

Groundwater recharge estimation is of fundamental significance to meet the agricultural water requirements, optimize water budget management, and further the sustainable development of water resources, particularly on coarse textured soil due to their rapid drainage behavior. The objectives of the study were to evaluate the feasibility and robustness of groundwater recharge estimation using one-dimensional physically based modelling coupled with weather stations and to interpolate the point estimates of recharge to a regional scale.Since the modelling results from different study areas coincided well with other studies, this method is feasible and robust to produce reliable point estimates of recharge universally. Four methods of recharge interpolation were applied in the second study area and were cross-validated by means of true percent error between the simulated and predicted recharge.The best prediction (7.8% true percent error) was obtained by ordinary kriging. Therefore, the methods of using physically based vadose zone modelling and kriging to estimate both points and regional recharge on coarse textured soil are feasible and extendable. / February 2017

Groundwater resources have become seriously threatened due to improper use by industrial, municipal, and even public sectors. Widespread contamination of aquifer systems has jeopardized human health and the environment and methods for restoring these systems are needed. Biological and chemical in situ remediation, where contaminants are degraded within the natural system, has become the foremost technique for cleaning up affected sites. However, before in situ remediation can be implemented, studies of the sites' physical, chemical, and biological characteristics must be done. Physical aquifer models (PAM's) were constructed for use in evaluating groundwater remediation strategies in porous media. The PAM's offer a unique approach for work of this kind, the most important of which are opportunity for conducting large-scale transport experiments under controlled conditions, and maintaining geometric, dynamic, and reactive similitude. The PAM's consist of aluminum reactors, 4.00 m (length) x 2.00 m (width) x 0.20 m (height), supported by a steel framework. Reservoirs at each end of the reactor permit adjustment of hydraulic gradient across its length. An array of 40 fully-penetrating wells allows versatility in sampling, injection, or extraction of solutes. Experiments can be performed under confined or unconfined, steady-state or transient conditions where temperature, pressure, and hydraulic gradient can be controlled. Plumbing design, well design, sampling protocol, and media-packing procedure were developed and tested in dye and bromide tracer experiments. The results of dye experiments in a water-filled PAM demonstrated the effectiveness of the inlet and outlet port design and construction of the wells. This was evident through control of a symmetrical plume that developed within a uniform flow field. Protocols for sampling, injection, and extraction using the well array were also effective based on observed dye plume development and bromide concentration contour plots. A new approach for packing sand was used to create a statistically equivalent homogeneous and isotropic porous media. Results of bromide tracer experiments indicate that this condition of homogeneity and isotropy was achieved. The PAM's worked well for creating the desired experimental conditions needed for studying transport of solutes (non-reactive in this case) in porous media. Additional experimental work will be done to develop and expand more of their capabilities (e.g. transient flow, confined conditions, heterogeneic media) for which they were designed. Remediation strategies will be investigated using the developed PAM's and it is hoped that results obtained from these studies will be successfully applied to field situations. / Graduation date: 1993

Hydraulic conductivity fields (K) and degradation rate constants (a) are commonly used in predicting the fate and transport of reactive contaminants. The natural heterogeneity in aquifer porous materials and its effect on hydrological parameters such as K and a has to be accounted for by using an appropriate stochastic approach. The spatial distribution of K and its correlation with a were examined. Random fields of K having prescribed mean, variance, and correlation lengths were generated using the HYDRO_GEN method. Transport simulations were conducted for an ensemble of two-dimensionally heterogeneous aquifers. Both positive and negative correlations of K and a were considered. The solute’s remaining mass in both the positive and negative correlation scenarios was found to be, on average, within a small range. Concentration profiles for a positive K-a correlation displayed a more uniform behavior of the contaminated plume, compared to a more variable spreading in the negatively correlated cases.