Earth Sciences Commons^™

Comparisons Of Hydrogeologic Modeling Methods To Define Capture Zones For Public Water Supply Wells In Northern Arkansas, Paula Anderson

Graduate Theses and Dissertations

The usefulness, applicability, and practicality of more complex and resource consuming methods for groundwater modeling has been in question since computer based groundwater modeling was established (Anderson, 1992). In many situations, computer modeling of groundwater flow is a necessity and useful for extrapolating data where none exists or it is impossible or impractical to acquire. However, when delineating a recharge area around a public water well for protection purposes, it is unknown if more detailed computer modeling results are better than simpler hydrologic calculations and site study. In the case of public drinking water supply wells located in various aquifers …

Vadose Zone Lag Time And Potential 21st Century Climate Change Effects On Spatially Distributed Groundwater Recharge In The Semi-Arid Nebraska Sand Hills, N. R. Rossman, Vitaly A. Zlotnik, Clinton Rowe, Jozsef Szilagyi

Department of Earth and Atmospheric Sciences: Faculty Publications

Deep drainage of water below plant root zones (potential groundwater recharge) will become groundwater recharge (GR) after a delay (or lag time) in which soil moisture traverses the vadose zone before reaching the water table. Depending on the thickness of the vadose zone, the magnitude of deep drainage, and soil hydraulic properties, lag times will vary broadly, exceeding decades to centuries in semi-arid and arid environments. Yet, studies of future climate change impacts to GR have typically avoided focusing on impacts beyond 100 years and often neglect to consider lag effects caused by the vadose zone. We investigate the effects …

Freshwater Resource Supply Modeling For Developed And Undeveloped Watersheds, Kelly C. Gustafson

FIU Electronic Theses and Dissertations

Globally, the current state of freshwater resource management is insufficient and impeding the chance at a sustainable future. Human interference within the natural hydrologic cycle is becoming dangerously irreversible and the need to redefine resource managerial approaches is imminent.

This research involves the development of a coupled natural-human freshwater resource supply model using a System Dynamics approach. The model was applied to two case studies, Somalia, Africa and the Phoenix Active Management Area in Arizona, USA. It is suggested that System Dynamic modeling would be an invaluable tool for achieving sustainable freshwater resource management in individual watersheds. Through a series …

Introduction: Geospatial Analysis Of Urban Environment, Changjoo Kim

International Journal of Geospatial and Environmental Research

To provide a timely snapshot of current research that utilizes geospatial analysis and modeling in urban environment, the Korea-America Association for Geospatial and Environmental Sciences (KAGES) and the editorship of the International Journal of Geospatial and Environmental Research (IJGER) organized a special issue of IJGER on the theme of geospatial analysis and urban environment. Eight articles out of 13 submitted manuscripts have been published in this issue. This article provides an overview of the articles published in the special issue.

Sustained High Basal Motion Of The Greenland Ice Sheet Revealed By Borehole Deformation, Claudia Ryser, Martin P. Lüthi, Lauren C. Andrews, Matthew J. Hoffman, Ginny A. Catania, Robert L. Hawley

Dartmouth Scholarship

Ice deformation and basal motion characterize the dynamical behavior of the Greenland ice sheet (GrIS). We evaluate the contribution of basal motion from ice deformation measurements in boreholes drilled to the bed at two sites in the western marginal zone of the GrIS. We find a sustained high amount of basal motion contribution to surface velocity of 44–73% in winter, and up to 90% in summer. Measured ice deformation rates show an unexpected variation with depth that can be explained with the help of an ice-flow model as a consequence of stress transfer from slippery to sticky areas. This effect …

Detection Of An Ultra Low Velocity Zone Beneath Central Mexico With Pcp Waveform Modeling, David James Buckley

Physics

PcP phases from a Guatemalan earthquake recorded at Nevada stations of the International seismic network (IM) display evidence of anomalous seismic structure at the core-mantle boundary (CMB); in particular, pre- and post-cursor phases to PcP and ScP. The data is examined for evidence of an ultra-low velocity zone (ULVZ) by identifying and modeling precursors to PcP. Precursory arrivals to PcP may be generated by the interaction of PcP with a thin layer above the core-mantle boundary (CMB). One-dimensional modeling demonstrates that standard earth models of the core-mantle boundary, which lack ULVZ structure, cannot produce the observed PcP data. …

Simulation Of Meteorological Fields For Icing Applications At The Summit Of Mount Washington, Sandra L. Jones

School of Natural Resources: Dissertations, Theses, and Student Research

Hazards related to in-cloud icing on aircraft and ground structures are important considerations for structural design, risk mitigation and operations. A variety of robust ice accretion algorithms exist for application dependent purposes; however, these algorithms are often dependent on reliable meteorological input data to be of use. This study investigates the potential for predicting meteorological parameters relevant to in-cloud icing episodes at ground level using the Weather Research and Forecasting (WRF) model. Model performance with regards to explicit simulation of super-cooled cloud liquid water content, cloud droplet diameter, temperature, and wind speed is evaluated against measurements collected at the summit …

Responses Of Hydrological Processes And Water Quality To Land Use/Cover (Lulc) And Climate Change In A Coastal Watershed, Ruoyu Wang

Ruoyu Wang

Coupled Sediment Yield And Sediment Transport Model To Support Navigation Planning In Northeast Brazil, Calvin Trebor Creech

Wayne State University Dissertations

Deposition of sediment (shoaling) in commercial waterways is a major obstacle to maintaining sustainable riverine transportation of bulk goods (primarily agricultural and mining commodities). The rate of aggradation of sediment in a waterway is directly related to both the rate of sediment erosion from upland and river bank sources (sediment yield) and the energy in the river to effectively transport the sediment through the waterway system (sediment transport). Historically, methods used for waterway development have included trial and error or rules of thumb associated with river training structures and chute cut-off canals or engineering of navigation locks and dams. More …

Investigation Of Fault-Related Small-Scale Fluid Flow In Geothermal Fields By Numerical Modeling, Doğa Doğan

Turkish Journal of Earth Sciences

In this paper, hydrothermal circulations and temperature distributions in geothermal areas with fault zones are investigated. It is shown that existence of the fault zones influences both the fluid circulation patterns and velocities. Reciprocal influence of the local fluid circulations and the temperature distribution is demonstrated. A 2-dimensional square porous layer is used for modeling the geothermal field. Faults are modeled as vertical porous layers. It is assumed that faults are located inside the geothermal field and have a higher permeability than the field itself. Anisotropic and isotropic models are used to simulate the permeability structure of the faults. Several …

Did A Submarine Landslide Contribute To The 2011 Tohoku Tsunami?, David R. Tappin, Stephan T. Grilli, Jeffrey C. Harris, Robert J. Geller, Timothy Masterlark, James T. Kirby, Fengyan Shi, Gangfeng Ma, K.K.S. Thingbaijam, P. Martin Mai

Civil & Environmental Engineering Faculty Publications

Many studies have modeled the Tohoku tsunami of March 11, 2011 as being due entirely to slip on an earthquake fault, but the following discrepancies suggest that further research is warranted. (1) Published models of tsunami propagation and coastal impact underpredict the observed runup heights of up to 40. m measured along the coast of the Sanriku district in the northeast part of Honshu Island. (2) Published models cannot reproduce the timing and high-frequency content of tsunami waves recorded at three nearshore buoys off Sanriku, nor the timing and dispersion properties of the waveforms at offshore DART buoy #21418. (3) …