Engineering Commons^™

Irrigation Water Quality—A Contemporary Perspective, Arindam Malakar, Daniel D. Snow, Chittaranjan Ray

Nebraska Water Center: Faculty Publications

In the race to enhance agricultural productivity, irrigation will become more dependent on poorly characterized and virtually unmonitored sources of water. Increased use of irrigation water has led to impaired water and soil quality in many areas. Historically, soil salinization and reduced crop productivity have been the primary focus of irrigation water quality. Recently, there is increasing evidence for the occurrence of geogenic contaminants in water. The appearance of trace elements and an increase in the use of wastewater has highlighted the vulnerability and complexities of the composition of irrigation water and its role in ensuring proper crop growth, and …

Modeled And Measured Ecosystem Respiration In Maize–Soybean Systems Over 10 Years, Ming Zhan, Adam Liska, Anthony Nguy-Robertson, Andrew E. Suyker, Matthew P. Pelton, Haishun Yang

Adam Liska Papers

Crop residue is an abundant resource for the potential production of biofuels, but a better understanding of its use on net carbon emissions must be developed to mitigate climate change. This analysis combines two established crop growth models (Hybrid-Maize and SoySim) with a simple soil and crop residue respiration model to estimate daily ecosystem respiration (ERe) from maize and soybean; ERe was estimated to be the sum of CO₂ emissions from the oxidation of the growing crop, crop residue, and soil organic carbon (SOC). Model-estimated CO₂ fluxes from irrigated continuous maize and irrigated maize–soybean cropping systems in eastern …

Twenty-Three Unsolved Problems In Hydrology (Uph) – A Community Perspective, Günter Blöschl, Christopher M. U. Neale, A Cast Of Thousands

Daugherty Water for Food Global Institute: Faculty Publications

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused …

Impact Of The Application Of Domestic Wastewater By Subsurface Drip Irrigation On The Soil Solution In Sugarcane Cultivation, Aline Azevedo Nazário, Ivo Zution Gonçalves, Eduardo Augusto Agnellos Barbosa, Leonardo Nazário Silva Dos Santos, Daniel Rodrigues Cavalcante Feitosa, Edson Eiji Matsura

Daugherty Water for Food Global Institute: Faculty Publications

The agricultural use of domestic sewage is a viable alternative for recycling nutrients; however, there is concern regarding the impact of its use due to the concentration of chemical elements present in this type of effluent. The use of principal component analysis determines the existence or lack of anomalous samples and the relations between measured variables and their relative contribution among samples that help in monitoring the impact of the use of effluents on soil chemical components. Thus, the objective of this work was to identify nutrient ions present in the soil solution during the first ratoon sugarcane irrigated with …

Public Attitudes About Private Forest Management And Government Involvement In The Southeastern United States, Melissa M. Kreye, Renata Rimsaite, Damian C. Adams

Daugherty Water for Food Global Institute: Faculty Publications

In the southern United States the country’s top wood-producing region, factors such as intergenerational land transfer and population spillover from urban areas have resulted in forestland conversion and reduced production of critical ecosystem services associated with forest systems (e.g., timber, clean water supply, wildlife habitat). Public attitudes, which drive forestland policy prescriptions, may also be evolving due to the way people experience and perceive forests (e.g., recreation), and think about the role of government in private forest decisions. These changes have significant implications for forestland management and the forest-based economy, both locally and globally. We present the results of a …

Mapping Regional Turbulent Heat Fluxes Via Assimilation Of Modis Land Surface Temperature Data Into An Ensemble Kalman Smoother Framework, Xinlei He, Tongren Xu, Sayed M. Bateni, Christopher M. U. Neale, Shaomin Liu, Thomas Auligne, Kaicun Wang, Shoudong Zhu

Daugherty Water for Food Global Institute: Faculty Publications

Estimation of turbulent heat fluxes via variational data assimilation (VDA) approaches has been the subject of several studies. The VDA approaches need an adjoint model that is difficult to derive. In this study, remotely sensed land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) are assimilated into the heat diffusion equation within an ensemble Kalman smoother (EnKS) approach to estimate turbulent heat fluxes. The EnKS approach is tested in the Heihe River Basin (HRB) in northwest China. The results show that the EnKS approach can estimate turbulent heat fluxes by assimilating low temporal resolution LST data from …

Agricultural Water Transfers In The Western United States, Richael Young, Nicholas Brozovic

Daugherty Water for Food Global Institute: Faculty Publications

Irrigation for agricultural production represents the largest consumptive use of water in the western United States. Understanding the ways in which agricultural producers respond to physical and institutional water scarcity is therefore key to managing water risk. One of the important risk management tools available to agricultural producers is the ability to transfer water across space and time. Water transfers range from very informal handshake agreements between neighbors to very formal transfers of real property across large distances with mandatory state and federal reporting. Given the range of potential water transfer mechanisms, there are significant knowledge gaps on the variety, …

2019 Nebraska Water Productivity Report, Mesfin Mekonnen, Christopher Michael Usher Neale, Chittaranjan Ray, Galen E. Erickson, Adam Liska, Haishun Yang, Thiago L. Romanelli, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Nebraska’s agricultural production is diverse and vast, ranking the state fourth in total value of agricultural products in the U.S. The state is a national leader in terms of agricultural production: it is the third largest producer of corn and second largest in cattle production. Nebraska is also the second largest producer of ethanol and distillers’ grains. The production and use of these three commodities are highly interlinked. Corn is a major input in livestock feed and the ethanol industry. Ethanol plants then produce distillers’ grains as a co-product that is also used as livestock feed, thus forming what the …

Cmas/Volcanic Ash Infiltration Performance Of Yttria Rich-Zirconia Thermal Barrier Coatings Produced By Electron Beam Physical Vapor Deposition, Juan Jose Gomez Chavez

Open Access Theses & Dissertations

For many years the use of thermal barrier coatings (TBC) in gas turbine engines has allowed a significant increase in engine operating temperatures which are above the Ni-based super alloys' melting point. The base material for TBCs is the state of the art 7 wt % yttria stabilized zirconia (YSZ) which provides the thermal protection. Current industry demands for increased engine efficiency has pushed TBCs to the limits where significant technological constrains have been identified. One of the main ones represents the high temperature corrosion of the TBC material due to the ingestion of silicate based airborne particles commonly referred …

Ua84 Sigma Chi, Wku Archives

WKU Archives Collection Inventories

Records created by and about the WKU chapter of Sigma Xi.

Effects Of Depositional Processes On Strength And Compressibility Of Sediments Using Elastic Shear Wave Velocity, Wisam Razzaq Muttashar

Theses and Dissertations--Earth and Environmental Sciences

Depositional processes are the most critical, complicated conditions that govern sediment properties and their variations, which in turn significantly affect the geotechnical behavior of the sediment. The complexity of depositional and post-depositional processes, which results in a variety of depositional environments, makes constructing a plausible model for the consolidation process of sediments difficult. The mutual influence between the temporal and spatial variation of depositional environments with their resultant physical and mechanical properties cause several compression issues, such as consolidation settlement and land subsidence, which mostly occur in estuarine-riverine regions throughout the world.

The first aim of this study is proposing …

Use Of Seismic Refraction In Determining Rock Mass Anisotropy, Mohammad Najmush Sakib Oyan

Electronic Theses and Dissertations

Seismic refraction is a popular method used by geological/geotechnical engineers to understand subsurface conditions. This method along with information collected from borings produce a realistic image of the ground beneath us. The goal of this study is to define and test a set of procedures to use seismic refraction alone to create high quality images of subsurface conditions. The focus is on areas with several meters of soil overlain by bedrock. The application of these procedures will minimize construction costs by eliminating the need for multiple boreholes. The results show that two important criteria must be met for successful application …

Efficient Intensity Measures Of Slide-Rocking Structures For Precariously Balanced Rocks, Taylor J. Knickerbocker, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

Precariously balanced rocks (PBRs) and other fragile geologic features are important in both the engineering and seismological communities since they are indicative of the maximum ground motion at a site over the rock’s lifetime. Precariously balanced rocks are individual or stacks of freestanding rocks that tend to respond in rigid body modes when subject to seismic excitation – namely, rocking, sliding, slide-rocking, and free-flight, which can lead to overturning. The seismic response of freestanding structures, such as PBRs, is known to be extremely sensitive to small changes in geometry, position, and earthquake excitation. As such, deterministic methods are limited in …

Experimental Investigation Of The Dynamics Of Trapped Non-Wetting Droplets Subjected To The Seismic Stimulation In Constricted Tubes: Supporting Information, Yandong Zhang, Chao Zeng, Baojun Bai, Wen Deng

Research Data

• Aspect Ratio of 4.5
• Aspect Ratio of 9.0
• Video Demos

Internet Of Things In Smart Agriculture: Enabling Technologies, Abdul Salam, Syed Shah

Faculty Publications

In this paper, an IoT technology research and innovation roadmap for the field of precision agriculture (PA) is presented. Many recent practical trends and the challenges have been highlighted. Some important objectives for integrated technology research and education in precision agriculture are described. Effective IoT based communications and sensing approaches to mitigate challenges in the area of precision agriculture are presented.

Mechanics And Historical Evolution Of Sea Level Blowouts In New York Harbor, Praneeth Gurumurthy, Philip Orton, Stefan A. Talke, Nickitas Georgas, James F. Booth

Civil and Environmental Engineering Faculty Publications and Presentations

Wind-induced sea level blowouts, measured as negative storm surge or extreme low water (ELW), produce public safety hazards and impose economic costs (e.g., to shipping). In this paper, we use a regional hydrodynamic numerical model to test the effect of historical environmental change and the time scale, direction, and magnitude of wind forcing on negative and positive surge events in the New York Harbor (NYH). Environmental sensitivity experiments show that dredging of shipping channels is an important factor affecting blowouts while changing ice cover and removal of other roughness elements are unimportant in NYH. Continuously measured water level records since …

Hydroclimate Drivers And Atmospheric Dynamics Of Floods, Nasser Najibi

Dissertations and Theses

Our preliminary survey showed that most of the recent flood-related studies did not formally explain the physical mechanisms of long-duration and large-peak flood events that can evoke substantial damages to properties and infrastructure systems. These studies also fell short of fully assessing the interactions of coupled ocean-atmosphere and land dynamics which are capable of forcing substantial changes to the flood attributes by governing the exceeding surface flow regimes and moisture source-sink relationships at the spatiotemporal scales important for risk management. This dissertation advances the understanding of the variability in flood duration, peak, volume, and timing at the regional to the …

Characterization Of Claypan Soils In Southeastern Kansas, M. A. Mathis Ii, S. E. Tucker-Kulesza, G. F. Sassenrath

Kansas Agricultural Experiment Station Research Reports

Soil erosion reduces topsoil depth. In areas with a claypan, removal of productive topsoil reduces crop yield where the claypan layer is near the surface. The topsoil and claypan layer each have unique characteristics that impact crop production and within-field variability. To better understand these differences, the soil from an area of low crop yield and high crop yield were collected and laboratory tests were performed to determine the soil classification and undrained shear strength. Understanding the soil properties and the interaction between the topsoil and claypan layers may aid in under­standing the process by which topsoil is being eroded.

Decomposing A Watershed’S Nitrate Signal Using Spatial Sampling And Continuous Sensor Data, Evan Clare

Theses and Dissertations--Civil Engineering

Watershed features, physiographic setting, geology, climate, and hydrologic processes combine to produce a time-variant nutrient concentration signal at the watershed outlet. Anthropogenic influences, such as increased agricultural pressures and urbanization, have increased overall nutrient loadings delivered to the fluvial network. The impact of such increased nutrient loadings on Kentucky’s drinking water remains a potential threat to the region.

By coupling spatial sampling of nitrate concentrations in surface water with contemporary nutrient and water quality sensor technology, a decomposition of the Upper South Elkhorn watershed’s nitrate signal and an estimation of source timing and loading in the watershed was completed. The …

Coupled Thermal-Hydrological-Mechanical-Chemical Processes In Geothermal And Shale Energy Developments, Arash Kamali-Asl

Graduate College Dissertations and Theses

Coupled Thermal-Hydrological-Mechanical-Chemical (THMC) processes that exist in the development of different geo-resources (e.g. deep geothermal and shale gas) affect the fracture response (i.e. aperture and permeability), which in turn influences the reservoir production. The main goal of this study was to experimentally evaluate the impact of THMC processes on the response of rock specimens relevant for deep geothermal and shale gas formations. The effects of THMC processes were investigated on: (i) success of the hydraulic fracturing/hydro-shearing mechanism during stimulation stage, and (ii) closure of the created network of fractures during production stage.

The elastic, cyclic, creep, and failure characteristics of …

Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu

Civil & Environmental Engineering Faculty Publications

The Baiyun slide complex contains geological evidence for some of the largest landslide ever discovered in the continental slopes of the South China Sea. High-resolution seismic data suggest that a variety of landslides with varied scales have occurred repeatedly in this area. The largest landslide reconstructed from bathymetric and seismic data has an estimated spatial coverage of ~5,500 km² and a conservative volume of ~1,035 km³. Here, using geomorphological and geotechnical data, we construct a series of probable landslide scenarios and assess their tsunamigenic capacity. By treating the slides as deformable mudflows, we simulate the dynamics of …

Temporal Changes Of Nutrients Within The Lower Grand River Watershed And Selected Sites, Weston Scott Duley

Masters Theses

"This report presents the results of a study carried out in collaboration with the U.S. Geological Survey (USGS) and the Missouri Department of Natural Resources (MDNR) to estimate total nitrogen (TN) and total phosphorus (TP) at five USGS monitoring sites within Lower Grand River Watershed (LGRW) and two monitoring sites on the Missouri River. The objective of this study was to quantify temporal changes in TN and TP concentrations and compare those to best management practices (BMPs).

In this study, the approach to the analysis of long-term surface water-quality data by using Weighted Regressions on Time, Discharge and Seasons models …

Geophysical Imaging Beneath Lake Chesterfield, Missouri, James Daniell Hayes

Masters Theses

"Lake Chesterfield in Wildwood, Missouri, has been leaking since construction of the earth-fill dam was completed in 1986, despite numerous mitigation efforts. The mitigation efforts, including the injection of grouting and the emplacement of clay liners, has not solve the leakage problem.

In the current study, geophysical (subsurface imaging) data was acquired across the drained and dry lake bed and along the base of the earth-fill dam to 1) map variable depth to top of bedrock, 2) determine the variable quality of the bedrock to depths on the order of 80 ft., 3) identify any significant karst features beneath the …

Bigger Tides, Less Flooding: Effects Of Dredging On Barotropic Dynamics In A Highly Modified Estuary, David K. Ralston, Stefan Talke, W. Rockwell Geyer, Hussein A. M. Al-Zubaidi, Christopher K. Sommerfield

Civil and Environmental Engineering Faculty Publications and Presentations

Since the late nineteenth century, channel depths have more than doubled in parts of New York Harbor and the tidal Hudson River, wetlands have been reclaimed and navigational channels widened, and river flow has been regulated. To quantify the effects of these modifications, observations and numerical simulations using historical and modern bathymetry are used to analyze changes in the barotropic dynamics. Model results and water level records for Albany (1868 to present) and New York Harbor (1844 to present) recovered from archives show that the tidal amplitude has more than doubled near the head of tides, whereas increases in the …

Pawnee Dam Inflow Design Flood (Idf) Update And Stage-Frequency Curve Development Using Rmcrfa, Jennifer P. Christensen, Joshua J. Melliger

United States Geological Survey: Water Reports and Publications

Pawnee Dam is one of the ten Salt Creek Dams designed and built in the 1960s to mitigate flooding in Lincoln, Nebraska. This short paper illustrates the update of the Pawnee Dam inflow design flood (IDF) through calibration to recent high flow events and the development of its stage-frequency or hydrologic loading curve with the U.S. Army Corps of Engineers’ Risk Management Center Reservoir Frequency Analysis (RMC-RFA) model. The IDF update follows Engineering Regulation 1110-8-2, Inflow Design Flood for Dams and Reservoirs, including unit hydrograph peaking and two antecedent pool elevations. Background information on the original design of the dam …