Civil and Environmental Engineering Commons^™

Estimating Seasonal Crop Water Consumption In Irrigated Lands Using Soil Moisture And Reference Evapotranspiration, Oliver Henry Hargreaves

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The increase in population and the megadrought that the American west has been experiencing for the past two decades and for the foreseeable future are the cause of great stress on the region’s water resources. In an effort to mitigate the worst effects of water shortages many public and private agencies have been pursuing ways to reduce water use while maintaining the current status quo of living standards, industrial productivity, and agricultural yield. This project aims to study water use in irrigated lands dedicated to agriculture with the objective of quantifying crop water use, often referred to as evapotranspiration (ET), …

Comparison Of Crop Water Use Estimation Methodologies In Irrigated Crops, Laura Christiansen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As increasing drought events limit water resources available for irrigation, farmers and other water users are looking for ways to monitor how much water crops use over a growing season. The amount of water used by crops over time is the evapotranspiration (ET) rate. This study compares different methods for ET estimation to recommend methods to water users based on their accuracy, efficiency, and accessibility. Each method was used to estimate ET for sprinkler-irrigated corn and alfalfa fields in Modena, UT over the 2021 growing season. The Soil Moisture based ET (SMET) method was used to estimate ET based on …

Improvement Opportunities In The Two-Source Energy Balance Model For Et Using Uav Imagery And Point Cloud Information, Mahyar Aboutalebi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In recent years, satellites and unmanned aerial vehicles (UAVs) provide enormous amounts of spatially-distributed information for monitoring crop conditions by measuring crop’s reflected and emitted radiation at a distance. However, applications of high-resolution UAV imagery and its intermediate products for improving crop water use estimates are not well studied. In other words, the available approaches, methods and algorithms for determining how much water to apply for irrigation using remotely sensed data have been mostly developed at satellite spatial resolutions. High-resolution imageries that have been achieved by small UAVs open new opportunities for revisiting, re-evaluating, and revising available crop water use …

Hydro-Climatic Changes And Corresponding Impacts On Agricultural Water Demand In The Ganges Delta Of Bangladesh, Sonia Binte Murshed

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Ganges Delta in Bangladesh, a transboundary rural river basin, is an example of water-related calamities due to natural and human-induced stresses. It is an agriculture-dominated area with the presence of Sundarbans mangrove forest. Recently this area is facing unfavorable conditions due to limitations in quantity, quality, and timing of available freshwater. As a result, floods, droughts, water scarcity, stream depletion, salinity intrusion, excessive sedimentation are becoming common phenomena. These calamities are making this area unsuitable for agriculture and vulnerable to the Sundarbans’ ecosystem. This study aims to provide technical insight into issues related to water scarcity and projected agricultural …

Advancing Methods To Quantify Actual Evapotranspiration In Stony Soil Ecosystems, Kshitij Parajuli

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water is undeniably among the most important natural resources and the most critical in semi-arid regions like the Intermountain West of the United States. Such regions are characterized by low precipitation, the majority of which is transferred to the atmosphere from the soil and vegetation as evapotranspiration (ET). Quantification of ET is thus crucial for understanding the balance of water within the region, which is important for efficiently planning the available water resources. This study was motivated towards advancing the estimation of actual ET (ET_A) in mountain ecosystems, where the variation in different types of vegetation and non-uniformity …

Estimating Evapotranspiration Using The Complementary Relationship And The Budyko Framework, Homin Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Land surface actual evapotranspiration (ET) is an important process in terrestrial water balance and reliable estimates of ET are necessary to improve water resources management. In this regard, there is a growing body of literature that recognizes the importance of an accurate ET model. Among them, the complementary relationship between ET and potential ET (ETP) has been the subject of many studies because it uses only meteorological data as inputs. However, there is an increasing concern that some complementary relationship models perform poorly under dry conditions. To overcome this limitation, this dissertation was designed to extend the latest complementary relationship …

Analyzing Irrigation District Water Productivity By Benchmarking Current Operations Using Remote Sensing And Simulation Of Alternative Water Delivery Scenarios, Jonna D. Van Opstal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The competition for fresh water is vastly increasing particularly in semi-arid areas. Agricultural irrigation areas are urged to decrease their water use, being the largest consumer of fresh water in these areas. Improvements in irrigation management aim at increasing crop production whilst maintaining or decreasing water use. The analysis of water productivity at the irrigation district scale is challenging due to spatial heterogeneity between fields and temporal variability between growing seasons.

This dissertation makes use of satellite-based remote sensing imagery and an irrigation system simulation model to determine the water management at different spatial scales from field scale to the …

Evapotranspiration Estimation: A Study Of Methods In The Western United States, Clayton S. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Theoretical water use of well-watered vegetation in the western United States was investigated by comparing a gridded dataset developed from satellite and ground instruments to weather stations representative of irrigated agricultural conditions. Since wetter environments are cooler and therefore subject to lower levels of evaporation than the same scenario with warmer temperatures, models derived from dryland and often populated areas overestimate potential plant needs in semi-arid or arid conditions. Evaluation of the model revealed an acceptable fit for air temperatures and solar radiation but with less confidence in humidity and wind speeds. Ultimately, the last two parameters were minor components …

Evapotranspiration Modeling And Forecasting For Efficient Management Of Irrigation Command Areas, Roula Bachour

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It has become very crucial to manage water resources to meet the needs of the growing population. In irrigation command areas, and in order to build a better plan to manage service delivery from canals and reservoirs, it is important to build appropriate knowledge of water needs on a field basis. There is often a lag between the order and delivery of water to the field. Knowledge of the crop water requirement at the field level helps the decision maker to make the right choices leading to more efficient handling of the available water. The purpose of this study was …

Estimation Of Field Alfalfa Evapotranspiration In A Windy, Arid Environment, J. Burdette Barker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Evapotranspiration (ET) of center pivot irrigated alfalfa was studied in the windy, arid, Curlew Valley, Northern Box Elder County, Utah, during the summers of 2009 and 2010. ET was estimated using eddy covariance (EC) and surface renewal (SR) techniques. ET estimates from the EC and SR analyses were compared with estimates using ASCE Standardized Reference ET Equation, with both dual and mean crop coefficients.

EC energy balance closure was 0.80, on average, in 2009 and 0.76 in 2010. The SR weighting parameter (α) was calculated through linear regression of EC and SR sensible heat flux estimates. Alpha was found to …

Water And Energy Balance Of A Riparian And Agricultural Ecosystem Along The Lower Colorado River, Saleh Taghvaeian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spatially-distributed water consumption was modeled over a segment of the Lower Colorado River, which contains irrigated agricultural and Tamarisk-dominated riparian ecosystems. For the irrigation scheme, distributed evapotranspiration data were analyzed in conjunction with point measurements of precipitation and surface flow in order to close daily and annual water balance. The annual closure error was less than 1% of the total water diversion to the area. In addition, it was found that the soil water storage component of the water balance cannot be neglected if the analysis is performed over time frames shorter than annual (e.g. growing season).

Water consumption was …

Spatial Variability And Error Limits Of Reference Evapotranspiration Estimates, Thomas W. Ley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The overall objective of this research was to develop a methodology for assessing the spatial variability and error limits of reference evapotranspiration (ET_r) estimates from a weather station network. Likely errors introduced into ET_r estimates due to sensor measurement variability and nonstandard site conditions were investigated. Temporal and spatial correlation structures of the weather variables used to compute ET_r and of ET_r data collected over a three-year period by an operational agricultural weather station network were studied.

Results indicated that ET_r errors are minimal compared to inherent model error when sensors (of the type …

Calibration Of A Temperature-Radiation Evapotranspiration Equation For Utah, Payam Foroughi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two reference crop evapotranspiration (ETr) equations were calibrated to the reference crop of alfalfa using 45 meteorological datafiles from 13 scattered sites in Utah and four sites in the neigboring states of Idaho and Wyoming.

The calibrations were done against the Kimberly version of the Penman ETr formula. The first equation required measured inputs of mean air temperature and solar radiation. It was referred to as the Temperature- Radiation ETr equation (ETr= CT x T x Rs). The second equation required measured inputs of mean minimum and mean maximum air temperatures. It was referred to as the New Hargreaves equation …