Hydrology Commons^™

Assessing Machine Learning Utility In Predicting Hydrologic And Nitrate Dynamics In Karst Agroecosystems, Timothy Mcgill

Theses and Dissertations--Biosystems and Agricultural Engineering

Seasonal hypoxia in the Gulf of Mexico and harmful algal blooms experienced in many inland freshwater bodies is partially driven due to excessive nitrogen loading seen from agricultural watersheds. Within the Mississippi/Atchafalaya River Basin, many areas are underlain with karst features, and efforts to reduce nitrogen contributions from these areas have had varying success, due to lacking a complete understanding of nutrient dynamics in karst agricultural systems. To improve the understanding of nitrogen cycling in these systems, 35 months of high resolution in situ water quality and atmospheric data were collected and fed into a two-hidden layer extreme learning machine …

Assessing The Climate Water Balance Model’S Ability To Predict Soil Moisture Variability And Species Distribution Of A Forested Watershed In The Northern Cumberland Plateau, Katherine J. Love

Theses and Dissertations--Forestry and Natural Resources

Spatial patterns of moisture and tree species have been studied using environmental gradients, often represented by terrain attributes in GIS. With climate change, GIS terrain variables, which are static as long as the elevation remains unchanged, will not reflect alterations in temperature, water cycle, and atmospheric conditions. In this thesis, the commonly used terrain variables and climate water balance variables were evaluated and compared for their ability to explain soil moisture and tree species distributions in a forested watershed in the Northern Cumberland Plateau. The results suggest that GIS terrain variables generally perform better than climate water balance variables, however, …

Hydrologic Monitoring And 2-D Electrical Resistivity Imaging For Joint Geophysical And Geotechnical Characterization Of Shallow Colluvial Landslides, Matthew M. Crawford

Theses and Dissertations--Earth and Environmental Sciences

Landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical parameters. Field monitoring of hydrologic variables such as water content and water potential, coupled with geoelectrical measurements that can establish relationships used for geotechnical and landslide hazard investigations is deficient.

This study brings together different techniques to develop a methodology that connects geoelectrical measurements and shear strength. A field-based framework was established that includes (1) analysis of long-term soil moisture fluctuations within different landslides (2) establishment of constitutive and new equations that test the use of electrical conductivity to predict soil-water relationships and shear strength (3) …

Soil- And Groundwater-Quality Data For An Abandoned Cattle And Hog Feedlot In Henderson County, Kentucky, E. Glynn Beck, James S. Dinger, Eugenia Pena-Yewtukhiw, John H. Grove

Information Circular--KGS

Groundwater samples collected from a livestock well in southwestern Henderson County, Ky., contained nitrate-N concentrations greater than 20 mg/L, two times the U.S. Environmental Protection Agency’s maximum contaminant level. The well is located in an abandoned cattle and hog feedlot. The feedlot is located in an upland bedrock setting with Pleistocene loess overlying Pennsylvanian bedrock. One hundred twenty-one soil cores were collected to better define the areal extent of organic-rich soil believed to be the source of the elevated nitrate-N in the groundwater. Cores were collected on 25-ft centers to a depth of 4 ft below the land surface. Soil …

Assessment Of Row Crop, Alfalfa, And Pasture Field Practices On Groundwater Quality In An Upland Bedrock Setting, Henderson County, Kentucky: Report Of Soil- And Water-Quality Data, E. Glynn Beck, James S. Dinger, John H. Grove, Eugenia Pena-Yewtukhiw

Information Circular--KGS

An assessment of how present agricultural practices have influenced shallow groundwater and soil quality was conducted on a 540-acre farm in north-central Henderson County. Groundwater- and soil-quality data were collected from row crop (corn and soybean), alfalfa, and pasture fields. In addition to the field settings, groundwater and soil data were collected from the existing farmyard and an abandoned feedlot. Groundwater samples were analyzed for pH, specific conductance, temperature, oxidation-reduction potential, metals, anions, nutrients, herbicides, and various isotopes. Soil samples were analyzed for pH, bioavailable phosphorus, potassium, calcium, magnesium, zinc, organic matter, total nitrogen, and inorganic nitrogen (nitrate-N). Soil- and …

Modeling Transport Of Colloid-Bound Herbicides And Heavy Metals To Groundwater, Anastasios D. Karathanasis, R. E. Phillips, A. K. Seta

KWRRI Research Reports

Recent studies have suggested that contaminant transport to groundwater may be enhanced by association with colloidal particles. This study evaluated the role of water dispersible colloids with diverse mineralogical composition in co-transporting selected herbicides and heavy metals through intact soil columns. Colloid recovery in the eluents ranged from 45-90% for the herbicides and 10-60% for the heavy metals. The presence of colloids enhanced the transport of atrazine by 2-18%, and metolachlor by 8-30%. The corresponding increase for Cu and Zn was 2-150 and 5-30 times, respectively. For Pb, there was essentially no elution in the absence of colloids, suggesting nearly …

Groundwater Flow And Elastoplastic Stress-Strain Model For Cohesive Soils With Application To Channel Bank Stability, Richard A. Rohlf, Billy J. Barfield, Gary K. Felton

KWRRI Research Reports

A saturated-unsaturated groundwater flow and elastoplastic stress-strain finite element model was developed for simulating the mechanical behavior of rill and gully sized channel banks. The model coupled the two-dimensional saturated-unsaturated groundwater flow equation with a plane strain formulation of the virtual work equation. The constitutive relationship used the modified Cam clay yield function. The model included the effects of seepage force and variation in soil cohesive strength due to changes in water content and void ratio. A staggered solution procedure was used in which the groundwater equation was solved first to determine seepage force and soil cohesive force, and then …

Hydrology And Sedimentology Of Dynamic Rill Networks Volume Ii: Hydrologic Model For Dynamic Rill Networks, Lindell E. Ormsbee, George E. Blandford, John S. Montgomery, Laura B. Terrell, Billy J. Barfield, Daniel E. Storm

KWRRI Research Reports

A comprehensive model has been developed for use in modeling the hydrologic response of rill network systems. The model, which is called HYMODRIN, is composed of both a hydrologic runoff component and a hydraulic channel routing component. The hydrologic component of the model uses a Green Ampt infiltration approach linked with a nonlinear reservoir runoff model. The channel routing component of the model is baaed on a finite element solution of the diffusion wave equations. In order to account for backwater effects the model employs a dual level iteration scheme.

The model may be used in either a stand alone …

Hydrology And Sedimentology Of Dynamic Rill Networks Volume I: Erosion Model For Dynamic Rill Networks, Daniel E. Storm, Billy J. Barfield, Lindell E. Ormsbee

KWRRI Research Reports

No abstract provided.

Modeling Mass Transport In Aquifers: The Distributed Source Problem, Sergio E. Serrano

KWRRI Research Reports

This report presents a new methodology to model the time and space evolution of groundwater variables in a system of aquifers when certain components of the model, such as the geohydrologic information, the boundary conditions, the magnitude and variability of the sources or physical parameters are uncertain and defined in stochastic terms. This facilitates a more realistic statistical representation of groundwater flow and groundwater pollution forecasting for either the saturated or the unsaturated zone. The method is based on applications of modern mathematics to the solution of the resulting stochastic transport equations. This procedure exhibits considerable advantages over the existing …

Modeling Erosion On Long Steep Slopes With Emphasis On The Rilling Process, Michael C. Hirschi, Billy J. Barfield, Ian D. Moore

KWRRI Research Reports

A model of soil erosion, known as KYERMO, is presented which emphasizes those processes which are important on steep slopes. Particular emphasis is placed on modeling rill development and geometry since this is the least understood process in erosion mechanics. The model requires an input rill pattern.

Rainfall inputs to the model require the use of breakpoint rainfall and kinetic energy. Surface storage is calculated based on random roughness data of Linden (1979). Infiltration is modeled by use of the two layer Green-Ampt-Mein-Larson model as proposed by Moore and Eigel (1981). Runoff is related to rainfall excess and surface storage …

Improved Methods And Guidelines For Modeling Stormwater Runoff From Surface Coal Mined Lands, Michael E. Meadows, George E. Blandford

KWRRI Research Reports

The investgations, developments and guidelines for several hydrologic modeling strategies are presented. Investigations were conducted to determine appropriate event curve numbers for surface mined disturbed watersheds; and performance of four synthetic unit hydrograph models (SCS curvilinear, SCS single triangle, Williams and TVA double triangle) on 38 USDA experimental watersheds in 14 physiographic provinces using in excess of 270 events. A second test using only the SCS curvilinear unit hydrograph on 11 small watersheds and 48 events was conducted to investigate the excess rainfall pattern simulated with the curve number model. A procedure for developing a unit hydrograph using the time …

Predicting Infiltration And Surface Runoff From Reconstructed Spoils And Soils, Larry G. Wells, Andrew D. Ward, Ronald E. Phillips

KWRRI Research Reports

A laboratory system was fabricated to measure infiltration and runoff from spoil and soil profiles constructed in rectangular bins. Construction, calibration and operation of a rainfall simulator is discussed and instrumentation used to measure transient infiltration and transmittance of water through experimental profiles is described.

Spoil and soil materials from surface mines in Eastern and Western Kentucky were transported to the laboratory and used in constructing experimental profiles in rectangular bins (0.91 x 1.83 x 1.07 m). An extensive series of infiltration experiments were conducted utilizing a rainfall simulator and soil moisture monitoring instrumentation. A dual probe gamma density gauge …

Characterization Of Water Movement Into And Through Soils During And Immediately After Rainstorms, C. T. Haan

KWRRI Research Reports

The movement of water into and through soils in the unsaturated state is basic to many water resources problems including rainfall-runoff models, ground water recharge, irrigation, drainage, evapotranspiration and the movement of pollutants in soils. This study was conducted in an effort to determine if the flow equation based on Darcy's Law and the continuity equation could be used to describe watershed infiltration and thus be incorporated into hydrologic models.

The results of the study indicate that even on apparently uniform soils there is a great deal of variability in soil water properties. Handling this variability plus the difficulty of …

The Relation Between Soil Characteristics, Water Movement And Nitrate Contamination Of Ground Water, Grant W. Thomas, Matthew Mcmahon

KWRRI Research Reports

Soils from several areas in Kentucky were placed in columns and leached with Ca(NO₃)₂. Subsoils high in iron oxide were found to retard the leaching of nitrate very significantly. In other soils, the nitrate moved through as fast as or slightly faster than the water.

Field application of nitrogen to corn was most efficient when done in the spring or summer near the time that the corn takes it up. The one exception to this was a red soil, where fall application of nitrogen resulted in little loss due to the retarding effect mentioned in the …