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Browsing by Author "Warziniack, Travis, committee member"

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    A data-driven characterization of municipal water uses in the contiguous United States of America
    (Colorado State University. Libraries, 2024) Chinnasamy, Cibi Vishnu, author; Arabi, Mazdak, advisor; Sharvelle, Sybil, committee member; Warziniack, Travis, committee member; Goemans, Christopher, committee member
    Municipal water systems in the United States (U.S.) are facing increasing challenges due to changing urban population dynamics and socio-economic conditions as well as from the impacts of weather extremities on water availability and quality. These challenges pose a serious risk to the municipal water providers by hindering their ability to continue providing safe drinking water to residents while also securing adequate supply for economic growth. A data-driven approach has been developed in this study to characterize the trends, patterns, and urban scaling relationships in municipal water consumption across the Contiguous United States. Then using sophisticated and robust statistical methods, water consumption patterns are modeled, identifying key climatic, socio-economic, and regional factors. The first chapter of this data-driven study looked at municipal water uses of 126 cities and towns across the U.S. from 2005 to 2017, analyzing the temporal trends and spatial patterns in water consumption and identifying the influencing factors. Water usage in gallons per person per day, ratio of commercial, industrial, and institutional (CII) to Residential water use, and percent outdoor water consumption were statistically calculated using aggregated monthly and annual water use data. The end goal was to statistically relate the variations in CII to Residential water use ratio across the municipalities with their local climatic, socio-economic, and regional factors. The results indicate an overall decreasing trend in municipal water use, 2.6 gallons per person annually, with greater reductions achieved in the residential sector. Both Residential and CII water use exhibit significant seasonality over an average year. Large cities, particularly in the southern and western parts of the U.S. with arid climates, had the highest demand for water but also showed the largest annual reductions in their per capita water consumption. This study also revealed that outdoor water use varied significantly from 3 to 64 percent of the Total water consumption across the U.S., and it was highest in smaller cities in the western and arid regions. Factors such as April precipitation, annual vapor pressure deficit, number of employees in the manufacturing sector, total percentage of houses built before 1950, and total percentage of single-family houses explain much of the variation in CII to Residential water use ratio across the CONUS. The second chapter leverages high-resolution, smart-metered water use data from over 900 single-family households in Arizona for the water year 2021. This part of the study characterizes the determinants or drivers of water consumption patterns, specifically in single-family households, and presents a framework of statistical methods for analyzing smart-metered water consumption data in future research. A novel approach was developed to characterize household appliance efficiency levels using clustering techniques on 5-second interval data. Integrating water consumption data with detailed spatial information of the household and building characteristics, along with local climatic factors, yielded a robust mixed-effects model that captured the variations in household water uses with high accuracy at a monthly time-step. Local air temperature, household occupancy level, presence of a swimming pool, the year the household was built, and the efficiency of indoor appliances and irrigation systems were exhibited to be the key factors influencing variations in household water use. The third and fourth chapter of this study reanalyzed the water consumption data of those 126 municipalities. The third chapter dwelled into the estimation of the state of water consumption efficiencies or economics of scale in the municipal water systems using an econometrics framework called urban scaling theory. A parsimonious mixed-effects model that combined the effects of socio-economic, built environment, and regional factors, such as climate zones and water use type, was developed to model annual water uses. The results confirm efficiencies in water systems as cities grow and become denser, with CII water use category showing the highest efficiency gains followed by the Residential and Total water use categories. A key finding is the estimation of the unique variations in water use efficiency patterns across the U.S. These variations are influenced by factors such as population, housing characteristics, the combined effects of climate type and geographical location of the cities, and the type of water use category (Residential or CII) that dominates in each city. The fourth or the final chapter synthesizes the lessons learned previously about the drivers of municipal water uses and explores the development of a model for predicting monthly water consumption patterns using machine learning algorithms. These algorithms demonstrated improved capabilities in predicting the Total monthly water use more accurately than the previous modeling efforts, also controlling for factors with multi-collinearity. Climatic variables (like precipitation and vapor pressure deficit), socio-economic and built environment variables (such as income level and housing characteristics), and regional factors (including climate type and water use type dominance in a city), were confirmed by the machine learning algorithms to strongly influence and cause variations in the municipal water consumption patterns. Overall, this study showcases the power of data-driven approaches to effectively understand the nuances in municipal water uses. Integration of the lessons learned and the statistical frameworks used in this study can empower water utilities and city planners to manage municipal water demands with greater resiliency and efficiency.
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    Integrated assessment of water shortage under climate, land use, and adaptation changes in the contiguous United States
    (Colorado State University. Libraries, 2024) Gharib, Ahmed AbdelTawab Fahmy AbdelMeged, author; Arabi, Mazdak, advisor; Goemans, Christopher, committee member; Sharvelle, Sybil, committee member; Warziniack, Travis, committee member
    Water scarcity is a critical global challenge. Water managers pursue water supply- and demand-side strategies, including construction or enhancement of water supply systems, conservation, and water reuse, to address water security driven by changes in climate, population, and land use. However, the effects of these strategies to mitigate future water shortages under dynamic climate and socioeconomic conditions at various spatial and temporal scales remain unclear. The overarching goal of this dissertation is to (1) improve understanding of the interconnections and interactions between climate, socioeconomic, hydrological, and institutional factors that influence water shortage at the river basin level, and (2) conduct an integrated assessment of water and land use management strategies. The dissertation is organized into three research studies. The first study explores water shortages in the South Platte River Basin (SPRB) and the potential benefits of investing in storage infrastructure and demand management strategies. The second study develops a methodology to understand the interactions between land use planning, water demands, shortage vulnerability, and effects on associated economic value. The third study expands the integrative assessment framework to assess changes in water demand, supply, and withdrawals, and identify effective mitigation strategies across river basins in the Contiguous United States over a range of climatic and socioeconomic pathways that are forecasted for the coming decades. In the first study, we develop data analysis and modeling tools to project water demands, supply, and shortages in the SPRB by the mid and end of the 21st century, examine the efficacy of adaptation strategies to reduce water shortages, and explore conditions under which reservoir storage and demand management would serve benefits for reduction of the vulnerability of economic sectors to water shortages. We implement two demand modeling tools to simulate the current and future urban and agricultural water demand in the river basin. Water yield is simulated using calibrated and tested Variable Infiltration Capacity (VIC) model. The estimated water demands and supplies are integrated using the Water Evaluation and Planning (WEAP) model to simulate water allocation with a half-monthly timestep to 70 aggregate users in the basin. Population growth, climate change, reservoir operations, and institutional agreements were considered during the modeling. The study reveals that the vulnerability to water shortages across sectors would increase without adaptation strategies. Population growth tends to be the primary driver of water shortages in the river basin. Reservoirs in the basin can relieve the sequences of the earlier seasonal shift of the water supply by capturing water during the high flow to be used in the high-demand seasons. However, additional storage is only beneficial up to a threshold of storage capacity to the water supply mean ratio of 0.64. The second study focuses on integrating the effects of land use planning and water rights institutions into the shortage analysis of the SPRB. The goal is to build a framework to understand the complex interactions between climate change, water rights institutions, urban land use planning, and population growth, and how they collectively impact the water shortage and economic analysis. We apply this framework to the SPRB simulate three water institutions, update the urban demand modeling to be a function of the population density, and test different scenarios of population locations throughout the basin. Results show that changing water rights institutions has a small impact on total shortages compared to climate change, but substantially impacts which users experience shortages. Land use policies influencing population locations have larger impacts on shortage and economic value compared to water rights. Finally, distributing the population more evenly between upstream and downstream regions reduces water shortages and increases associated economic value regardless of water rights institutions and climate conditions. The third study employs an integrative modeling assessment framework to assess water shortage and effective mitigation strategies in river basins across the Contiguous United States. The goals are to improve the methodologies for estimation of water withdrawals, consumptive use, and water shortage, and explore the effectiveness of supply- and demand-side adaptation strategies. The simulated demands are integrated with the water supply components (groundwater, interbasin transfers, water yield, and reservoirs) into a water allocation model for simulating shortage under different scenarios. Results reveal that irrigation has the highest historical and future consumptive use, over 75% of the total consumptive use. Although the consumptive use ratio receives little attention in the literature, it appears to be the most significant parameter for shortage calculations. The allocation model provides comprehensive shortage analysis considering shortage volume, ratio, and frequency across multiple scenarios for the 204 sub-regions ā€“Hydrologic Unit Code 4 watershedsā€“ of the Contiguous United States. Water shortages concentrate between the boundaries of the West Region with both the Midwest and the South regions, in addition to Arizona, Florida, and the center valley of California. Relying only on sustainable groundwater pumping rates is essential to stop the ongoing groundwater depletion, but adds more pressure on demand reduction strategies. The ongoing research examining water demand, supply, and shortage is important and requires further integration of the key influencing variables. This dissertation demonstrates the necessity of an integrated approach to fully understand the relative impacts of the main drivers of water allocation and shortage. We highlight that reservoirs play a vital role in balancing seasonal fluctuations in the water supply. However, their effect on the 30-year mean annual shortage is effective until the storage volume ratio to mean water supply exceeds 64%. Additionally, land use policies carry higher direct significance on water shortages compared to water rights. We find that distributing the population more evenly throughout the river basin provides the lowest shortage. Lastly, the approaches targeting shortage calculation and mitigation should analyze both regional and national scenarios under integrated frameworks comparing demand- and supply-side options.
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    Modeling the impact of transaction costs and alternative supply sources on water market activity in the western U.S.
    (Colorado State University. Libraries, 2017) Bauman, Allison, author; Goemans, Christopher, advisor; Thilmany, Dawn, advisor; Pritchett, James, committee member; Arabi, Mazdak, committee member; Warziniack, Travis, committee member
    To view the abstract, please see the full text of the document.
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    Optimizing the net benefits from pre-wildfire treatments to Colorado-Big Thompson Headwaters Partnership water recipients
    (Colorado State University. Libraries, 2014) Miller, John, author; Suter, Jordan, advisor; Frasier, Marshall, committee member; Warziniack, Travis, committee member; Coleman, Robert, committee member
    To view the abstract, please see the full text of the document.
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    The influence of climate, amenities and socio-economic factors on population growth in areas around western national forest land
    (Colorado State University. Libraries, 2015) Weiss, David, author; Loomis, John, advisor; Joyce, Linda, committee member; Warziniack, Travis, committee member; Weiler, Stephan, committee member
    Understanding factors that do and do not affect population change helps public land managers anticipate future population changes around national forests and informs future land management planning decisions. This study examines the effects of climate, natural and manmade amenities and socio-economic factors on population growth in rural counties in the West that contain national forest land. Further, it employs a series of forecasting models to estimate population change through 2060 under multiple climate change scenarios and a baseline climate scenario, with particular focus on the five Wyoming counties that contain the Shoshone National Forest. Cross-sectional analysis of population growth from 2000 to 2010 indicates that a wide range of variables are significant in predicting population change. Within the class of climate variables, average low winter temperature exhibits a highly significant negative correlation with population change (i.e. as winter temperatures rise, population growth slows). Average high summer temperature also has a significant negative correlation with population growth, though only when analyzed independently of average low winter temperature. Estimated population growth rates through 2060 tended to be higher among sampled counties with larger base populations. For the most part, forecasting models predicted increases in population for the five Shoshone counties. Among these counties, projected percent change in population from 2010 to 2060 varied considerably less across models for the three counties with relatively larger base populations. Across forecasting models, aggregated predicted population increases for the Shoshone region varied from 65.4% to 154.2%. A relatively small portion of this anticipated population growth was attributable to forecasted increases in summer and winter temperatures, compared to the underlying trend of higher predicted growth rates among counties with higher base year populations.
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    Vulnerability of U.S. river basins to water shortage over the 21st century
    (Colorado State University. Libraries, 2021) Heidari, Hadi, author; Arabi, Mazdak, advisor; Warziniack, Travis, committee member; Brown, Thomas C., committee member; Bailey, Ryan, committee member; Goemans, Christopher G., committee member
    Future changes in climate and population across the United States may cause a decrease in freshwater availability and an increase in water demand. These trends may lead to more frequent water shortage conditions when water demand exceeds water supply. The enhanced characterizations of changes in both longā€term anomalies such as aridity and evaporative indices and short-term anomalies such as multi-year and interannual water shortage events in a changing environment are requisite to the appropriate management and planning of future water resources, and improved implementation of regional adaptation and mitigation strategies. The main goal of this dissertation is thus to assess shifts in hydroclimatic conditions and water shortage (IDF) relationships across the conterminous United States (CONUS) over the 21st century. To achieve this goal, first, the effects of climate change on the regional hydroclimatology of U.S. river basins were assessed over the 21st Century to determine regions with prolonged dry or wetting periods. This analysis shows that U.S. river basins within the CONUS can be clustered into seven groups with unique hydroclimatic behaviors in response to climate change that are highly associated with regional landform, climate, and ecosystems of river basins. The South United States is more likely to experience warmer and drier conditions meaning higher chances of aridification. Second, the impact of climate change on hydroclimatic conditions of U.S. national forests (NFs) and national grasslands (NGs) was investigated. The results of this study indicate that NFs and NGs are more likely to experience larger changes in hydroclimatic variables compared to the average of the United States. The findings help environmental scientists and forest managers to mitigate the negative consequences of climate change on forest and grassland resources. Third, shifts in hydroclimatology of U.S. megaregions in response to climate change were investigated. This analysis reveals that Houston may experience more arid climatic conditions with higher evaporative loss of freshwater resources in the future. These steps provide an improved understanding of the effects of climate change on the regional aridification or desertification across the CONUS. To accomplish the goal of the study, fourth, a probabilistic approach was developed to improve the characterization of both within-year and over-year socioeconomic droughts in a changing environment. The proposed approach provides a procedure to update sub-annual socioeconomic drought IDF relationships while taking into account changes in water supply and demand. Fifth, the developed probabilistic approach was applied to examine the effects of urban development patterns, i.e., sprawl versus high-density development, on the socioeconomic drought characteristics. The results of this study highlight that urban regions under the sprawl development pattern are likely to experience more frequent socioeconomic drought events with higher intensity and longer duration compared to the high-density development pattern. Finally, the developed approach was implemented across the CONUS to characterize vulnerability of U.S. river basins to water shortage from 1986-2015 to 2070-2099 periods. The results show that prolonged water shortage conditions in drier basins and interannual water shortage events in wetter basins are likely to be the main concerns in the future and should gain more attention in future water resource planning and management.