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Response Of Deep Aquifers To Climate Variability, Karem Fathy Abdelgaber Abdelmohsen

Dissertations

Our recent analysis of Temporal Gravity Recovery and Climate Experiment (GRACE) solutions over the largest aquifer system in Africa (the Nubian Sandstone Aquifer System: NSAS) revealed that while the response of deep aquifers to climatic variations remains a relatively slow process that takes thousands to tens of thousands of years, there is a much faster response in aquifers that are characterized by dense networks of faults, fractures and karst as is the case with the NSAS. This rapid groundwater flow, when it occurs, is detected as an increase in GRACE_TWS over areas downgradient and distant (hundreds of km) from …

Evaluation Of Groundwater Sodium And Sodium Uptake In Taxodium And Its Hybrids On Galveston Island, Texas, Daniel Morgan

Electronic Theses and Dissertations

In September 2008, Hurricane Ike swept through the Gulf of Mexico striking the Gulf Coast, claiming hundreds of lives and causing billions of dollars in damage. The hurricane left behind elevated sea salt concentrations in the soil and groundwater, preventing the unaided return of live oaks and other species to the island. To determine effective ways to ameliorate the elevated Na⁺ concentrations in the soil, eight treatments were applied to the soil and combinations of three species of plants, live oak (Quercus virginiana), hybrid bald cypress (Taxodium ‘T406’), and yellow hibiscus (Hibiscus hamabo …

Water Chemistry And Lake Dynamics Of Laguna Bacalar, Quintana Roo, Mexico, Ryan Matzuk

Theses and Dissertations

Laguna Bacalar in the Quintana Roo region is the second largest lake in Mexico and contains freshwater derived solely from groundwater. Local geology on the Yucatan Peninsula is karstic and the southern shoreline of Laguna Bacalar is spotted with a handful of cenotes that contribute substantial amounts of inflowing groundwater to the lake. This is shown by sonde profile data taken in one of the largest cenotes in the area. Outflow is dominated by a surface water outlet in the southern portion of the lake and an unknown amount of outflowing groundwater. During January of 2017 through 2019, UWM researchers …

A Groundwater Model Of The San Luis Obispo Valley Basin Using Comsol Multiphysics, Brian Whetsler

Master of Science in Environmental Sciences and Management Projects

A groundwater model of a subsection of the San Luis Obispo Valley basin was pro- duced using COMSOL Multiphysics 5.5 software. The goal of this project was to create a general model using forward modeling techniques which would serve as the foundation for a more refined, complete, and calibrated groundwater hydrology model. The San Luis Obispo and Edna Valley basins are characterized as high-priority by the California Sustainable Groundwater Management Act because of historic overdrafting of groundwater reserves during periods of drought in the early 1990's. Natural resource managers must use tools such as computer models to help forecast trends …

A Geochemical And Statistical Investigation Of The Big Four Springs Region In Southern Missouri, Jordan Jasso Vega

MSU Graduate Theses

The Big Four Springs region hosts four major first-order magnitude springs in southern Missouri and northern Arkansas. These springs are Big Spring (Carter County, MO), Greer Spring (Oregon County, MO), Mammoth Spring (Fulton County, AR), and Hodgson Mill Spring (Ozark County, MO). Based on historic dye traces and hydrogeological investigations, these springs drain an area of approximately 1500 square miles and collectively discharge an average of 780 million gallons of water per day. The rocks from youngest to oldest that are found in Big Four Springs region are the Cotter and Jefferson City Dolomite (Ordovician), Roubidoux Formation (Ordovician), Gasconade Dolomite …

High-Resolution Timeseries Analysis Of Dynamic Geochemistry: A 27-Well Survey Of Contaminated Groundwater Downstream Of The Former S-3 Ponds, Oak Ridge, Tennessee, Emma Dixon

Masters Theses

Spatiotemporal variability of geochemistry of contaminated groundwater has large implications on overall water quality and ability to respond to remedial applications. Gaining knowledge of how geochemistry changes over time in an area can help establish response trends to changing external conditions like weather and level of contamination. In this study, a spatiotemporal survey was performed on 27 wells at the Y-12 Complex in Oak Ridge, Tennessee. This was completed to measure diurnal fluxes in geochemistry from seasonal changes and extreme weather conditions in three areas of historically different contamination levels from a single point contamination source. Measurements were gathered over …

Estimating Evapotranspiration Of A Riparian Forest Using Sap Flow Measurements, James R. Solum

Master's Theses

To close the water use budget of irrigated agricultural fields in floodplains with substantial riparian corridors, it is necessary to understand groundwater usage by dominant phreatophytic vegetation, particularly when the primary source of water for irrigation comes from groundwater abstraction. We report here results of estimated evapotranspiration (ET) of a riparian forest, which were based on measurements of sap flow in phreatophytic vegetation within a riparian corridor. The riparian corridor was within a study area 75 to 140 meters wide in the lower portion of the Scotts Creek watershed, which is bounded to the west by the Pacific Ocean in …

An Analysis Of Groundwater Quality As Sampling Networks Age: The Gaps In Groundwater Monitoring, Angela Leone

Undergraduate Distinction Papers

Groundwater management is an important facet of protecting this important resource. One way that we ensure proper groundwater management is through the regular, long-term monitoring of groundwater wells at waste management sites throughout the country. This study investigates potential changes to groundwater quality attributed to degradation of well construction materials rather than impacts to aquifers from wastes. This assessment was completed using a data analysis of groundwater trends at closed landfill sites. An analysis of fifty-five sites was completed and three sites met our criteria for suitable data history. Due to the lack of suitable data, a more thorough investigation …

An Evaluation Of Bank Storage At Lake Mead Reservoir In The Southwest United States, Jon Woodrow Wilson

UNLV Theses, Dissertations, Professional Papers, and Capstones

A water balance model is employed at Lake Mead to monitor and verify changing hydrology that affects total volume at the reservoir. Bank storage, which is defined as the volume of water captured in permeable lithologic layers subject to changes induced by contact and proximity to an open waterbody, is one component that is updated regularly and is based upon data and methods that were developed in the 1960’s from observations made within the first 30 years of the reservoir's maturation. Since this period, the reservoir has undergone further development and a current understanding of additional hydrologic affects to bank …

Field And Numerical Evaluation Of Nitrogen Transport From Septic Systems In Surfical Aquifer Systems To Charlotte Harbor, Florida, Tanten T. Buszka

Masters Theses

Shallow water tables in coastal surficial aquifers limit effective treatment of septic effluent which can result in excess nutrient loading into nearby surface water bodies. Approximately 45,000 septic systems in Charlotte County, Florida transmit effluent into an under studied surficial aquifer and contribute to harmful algal blooms and outbreaks of E. coli. An undeveloped field site was characterized using standard hydrogeologic methods, including a one-year duration natural gradient tracer test, to obtain representative lithology of the sandy surficial aquifer and estimates of groundwater velocity, flow directions, effective porosity and dispersion. These data were used to support the development of a …

Quantification Of Septic System Contribution To Nutrient Loads In Surface Waters, Archana Tamang

Electronic Thesis and Dissertation Repository

Freshwater systems worldwide are threatened by excessive nutrient (nitrogen and phosphorus) loading. This study evaluated the contribution of septic systems to stream nutrient loads in nine subwatersheds. Stream sampling was conducted during low and high discharge conditions, with samples analyzed for total phosphorus (TP), soluble reactive phosphorus (SRP), nitrate (NO₃-N), and acesulfame (ACE; wastewater tracer). Higher septic effluent reached the subwatershed outlets during high discharge conditions. Subwatersheds with newer households had a lower percentage of septic effluent reaching the stream compared with subwatersheds with older households. Seasonal and event-based ACE concentration-discharge relationships revealed that the hydrological pathways delivering …

Tidal-Groundwater Study Of The Slaughter Beach Salt Marsh In Slaughter Beach, De, Michael Powers

West Chester University Master’s Theses

Seasonal and decadal monitoring of salt marsh at Slaughter Beach, DE documented long-term and short-term variations in number and sizes of salt ponds. Over 400 salt ponds ranging in size between 0.5 m² to 0.11 km² were identified on 5.5 km² salt marsh platform. The purpose of this study is to quantify hydrologic conditions and measure groundwater discharge of a salt marsh, particularly the impact of tidal forces on groundwater fluctuation.

Four wells with nests of mini-piezometers with ONSET Pressure Transducers were installed along a transect crossing the largest salt pond (0.11 km²) in the …

A Geochemical Assessment Of Potential Groundwater Storage Locations Within The Yakima River Basin, Silas Sleeper

All Master's Theses

Currently in the Yakima River Basin more people possess surface water rights than there is available surface water. As a result, the local community devised the Yakima River Basin Integrated Water Management Plan, with the goal of creating a sustainable source of water for the foreseeable future. One of seven elements outlined in this plan is groundwater storage. The idea is to take available water during high spring flows and store it in the subsurface. The water will then be used to increase stream flows and decrease stream water temperatures during the summer months. A main challenge associated with groundwater …

Detecting Groundwater Discharge In The Clark Fork River Near Stone Container Using Spectral Alpha Decay Detection For Dissolved Radon In Surface Water Samples Abstract, Daniel William Forsland

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Radon-222 (²²²Rn) was measured along 8.7 kilometers of the Clark Fork River, between Harper’s Bridge and Frenchtown, MT. Twelve water samples were taken along the stretch. Samples 1 through 4 and 10 through 12 were collected on a 1 km interval, samples 5 through 9 were taken on a 500 meter interval. Samples were analyzed for dissolved ²²²Rn using a RAD7 spectral alpha decay detector. Instream ²²²Rn was modeled to quantify groundwater discharge to the river. Literature on the Missoula Valley aquifer was analyzed, revealing an alluvial aquifer system to the east consisting of interbedded gravel, …