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Browsing by Author "Marston, Landon T."

Now showing 1 - 17 of 17
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    Alleviating Water Scarcity by Optimizing Crop Mixes
    Richter, Brian D.; Ao, Yufei; Lamsal, Gambhir; Wei, Dongyang; Amaya, Maria; Marston, Landon T.; Davis, Kyle F. (Nature Portfolio, 2023-11)
    Irrigated agriculture dominates freshwater consumption globally, but crop production and farm revenues suffer when water supplies are insufficient to meet irrigation needs. In the United States, the mismatch between irrigation demand and freshwater availability has been exacerbated in recent decades due to recurrent droughts, climate change and over extraction that dries rivers and depletes aquifers. Yet, there has been no spatially detailed assessment of the potential for shifting to new crop mixes to reduce crop water demands and alleviate water shortage risks. In this study, we combined modelled crop water requirements and detailed agricultural statistics within a national hydrological model to quantify sub-basin-level river depletion, finding high-to-severe levels of irrigation scarcity in 30% of sub-basins in the western United States, with cattle-feed crops—alfalfa and other hay—being the largest water consumers in 57% of the region’s sub-basins. We also assessed recent trends in irrigation water consumption, crop production and revenue generation in six high-profile farming areas and found that in recent decades, water consumption has decreased in four of our study areas—a result of a reduction in the irrigated area and shifts in the production of the most water-consumptive crops—even while farm revenues increased. To examine the opportunities for crop shifting and fallowing to realize further reductions in water consumption, we performed optimizations on realistic scenarios for modifying crop mixes while sustaining or improving net farm profits, finding that additional water savings of 28–57% are possible across our study areas. These findings demonstrate strong opportunities for economic, food security and environmental co-benefits in irrigated agriculture and provide both hope and direction to regions struggling with water scarcity around the world.
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    Comparison of potential drinking water source contamination across one hundred US cities
    Turner, Sean W. D.; Rice, Jennie S.; Nelson, Kristian D.; Vernon, Chris R.; McManamay, Ryan; Dickson, Kerim; Marston, Landon T. (Nature Portfolio, 2021-12-13)
    In the U.S. today nearly no surface waters are drinkable without treatment. Here, the authors demonstrate that four-fifths of cities that withdraw surface water are supplying water that includes a portion of treated wastewater, concentrated in the Midwest, the South, and Texas. Drinking water supplies of cities are exposed to potential contamination arising from land use and other anthropogenic activities in local and distal source watersheds. Because water quality sampling surveys are often piecemeal, regionally inconsistent, and incomplete with respect to unregulated contaminants, the United States lacks a detailed comparison of potential source water contamination across all of its large cities. Here we combine national-scale geospatial datasets with hydrologic simulations to compute two metrics representing potential contamination of water supplies from point and nonpoint sources for over a hundred U.S. cities. We reveal enormous diversity in anthropogenic activities across watersheds with corresponding disparities in the potential contamination of drinking water supplies to cities. Approximately 5% of large cities rely on water that is composed primarily of runoff from non-pristine lands (e.g., agriculture, residential, industrial), while four-fifths of all large cities that withdraw surface water are exposed to treated wastewater in their supplies.
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    The environmental footprint of data centers in the United States
    Siddik, Md Abu Bakar; Shehabi, Arman; Marston, Landon T. (2021-06)
    Much of the world's data are stored, managed, and distributed by data centers. Data centers require a tremendous amount of energy to operate, accounting for around 1.8% of electricity use in the United States. Large amounts of water are also required to operate data centers, both directly for liquid cooling and indirectly to produce electricity. For the first time, we calculate spatially-detailed carbon and water footprints of data centers operating within the United States, which is home to around one-quarter of all data center servers globally. Our bottom-up approach reveals one-fifth of data center servers direct water footprint comes from moderately to highly water stressed watersheds, while nearly half of servers are fully or partially powered by power plants located within water stressed regions. Approximately 0.5% of total US greenhouse gas emissions are attributed to data centers. We investigate tradeoffs and synergies between data center's water and energy utilization by strategically locating data centers in areas of the country that will minimize one or more environmental footprints. Our study quantifies the environmental implications behind our data creation and storage and shows a path to decrease the environmental footprint of our increasing digital footprint.
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    Food Supplies and Demand Reliant on Large Irrigation Dams
    Tysinger, Wilson Andrew (Virginia Tech, 2023-07-18)
    Water is an integral part of agricultural practices, with agriculture being the largest user of surface water in the United States. Agriculture's reliance on surface water is strengthening as climate change and growing populations are stressing irrigated croplands. This surface water is primarily stored by a complex network of dams, but despite our reliance on surface water for irrigation, we lack a spatially detailed record of irrigation dam command areas. Therefore, we assigned irrigation command areas to the approximately 1,100 large irrigation dams in the continental United States by combining a tiered assignment strategy with field level infrastructure and agricultural data. We showed that these large irrigation dam command areas are responsible for 10.7 million acres of cropland. This translates to approximately 13.3 billion dollars of crops annually that depend on these large irrigation dams for water. The high-resolution, crop specific assignment of these command areas allows for water scarcity assessments that can be used for better water management decisions to address the changing environmental conditions and public demand pressuring the nation's agriculture and water infrastructure.
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    Growing farms and groundwater depletion in the Kansas High Plains
    Ao, Yufei Z.; Hendricks, Nathan P.; Marston, Landon T. (2021-08)
    The average farm size has more than doubled within the United States over the last three decades, transforming the agricultural industry and rural farming communities. It is unclear, however, how this ubiquitous trend has affected and is affected by the environment, particularly groundwater resources critical for food production. Here, we leverage a unique multi-decadal dataset of well-level groundwater withdrawals for crop irrigation over the Kansas High Plains Aquifer to determine the interactions between groundwater depletion and growing farms. Holding key technological, management, and environmental variables fixed, we show that doubling a farm's irrigated cropland decreases groundwater extractions by 2%-5% depending on the initial farm size. However, a corresponding shift by larger farms to different irrigation technologies offsets this reduction in groundwater use, leading to a slight increase in overall groundwater use. We find groundwater depletion increases the likelihood farmland is sold to a larger farm, amplifying the cycle of groundwater depletion and the consolidation of farmland.
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    The importance of fit in groundwater self-governance
    Marston, Landon T.; Zipper, Sam; Smith, Steven M.; Allen, Jonah J.; Butler, James J.; Gautam, Sukrati; Yu, David J. (IOP Publishing, 2022-10)
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    Inputs for staple crop production in China drive burden shifting of water and carbon footprints transgressing part of provincial planetary boundaries
    Feng, Bianbian; Zhuo, La; Mekonnen, Mesfin M.; Marston, Landon T.; Yang, Xi; Xu, Zenghui; Liu, Yilin; Wang, Wei; Li, Zhibin; Li, Meng; Ji, Xiangxiang; Wu, Pute (Pergamon-Elsevier, 2022-08-01)
    Crop production is the biggest water user and key contributor to anthropogenic greenhouse gas emissions. Increasing crop yields to ensure adequate food supply under water and land scarcity is excessively dependents on intensive agricultural inputs (such as fertilizers, pesticides, agri-films, or energy), resulting in unintended environmental consequences. Supply chains bringing environmental-intensive inputs from their place of production to the croplands. However, most food-related environmental assessments ignore the environmental burden of agricultural input production, trade, and consumption. Here, we estimate spatially-detailed water (WF) and carbon footprints (CF) of wheat, maize, and rice production in China with extended system boundary from upstream raw material mining to the field. The agricultural inputs account for up to 24% and 89% of a crop's WF and CF, respectively, at the provincial level. The total local generated WF in Chinese northern provinces and CF in Shanxi and Inner Mongolia provinces for producing crops and agricultural inputs transgresses the corresponding downscaled blue water and carbon planetary boundaries. The study broadens the scope of traditional environmental impact assessments in agricultural production and sheds light on the significances to manage the linkages between the crop production and the agricultural inputs' upstream supply chains towards more efficient water use and less greenhouse gas emissions in food system.
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    Interbasin water transfers in the United States and Canada
    Siddik, Md. Abu Bakar; Dickson, Kerim E.; Rising, James; Ruddell, Benjamin L.; Marston, Landon T. (Nature Portfolio, 2023-01-13)
    Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as well as basins downstream of these water transfers. The lack of comprehensive data identifying and describing IBTs inhibits understanding of the role IBTs play in supplying water for society, as well as their collective hydrologic impact. We develop three connected datasets inventorying IBTs in the United States and Canada, including their features, geospatial details, and water transfer volumes. We surveyed the academic and gray literature, as well as local, state, and federal water agencies, to collect, process, and verify IBTs in Canada and the United States. Our comprehensive IBT datasets represent all known transfers of untreated water that cross subregion (US) or subdrainage area (CA) boundaries, characterizing a total of 641 IBT projects. The infrastructure-level data made available by these data products can be used to close water budgets, connect water supplies to water use, and better represent human impacts within hydrologic and ecosystem models.
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    New water accounting reveals why the Colorado River no longer reaches the sea
    Richter, Brian D.; Lamsal, Gambhir; Marston, Landon T.; Dhakal, Sameer; Sangha, Laljeet Singh; Rushforth, Richard R.; Wei, Dongyang; Ruddell, Benjamin L.; Davis, Kyle Frankel; Hernandez-Cruz, Astrid; Sandoval-Solis, Samuel; Schmidt, John C. (Springer Nature, 2024-03-28)
    Persistent overuse of water supplies from the Colorado River during recent decades has substantially depleted large storage reservoirs and triggered mandatory cutbacks in water use. The river holds critical importance to more than 40 million people and more than two million hectares of cropland. Therefore, a full accounting of where the river’s water goes en route to its delta is necessary. Detailed knowledge of how and where the river’s water is used can aid design of strategies and plans for bringing water use into balance with available supplies. Here we apply authoritative primary data sources and modeled crop and riparian/wetland evapotranspiration estimates to compile a water budget based on average consumptive water use during 2000–2019. Overall water consumption includes both direct human uses in the municipal, commercial, industrial, and agricultural sectors, as well as indirect water losses to reservoir evaporation and water consumed through riparian/wetland evapotranspiration. Irrigated agriculture is responsible for 74% of direct human uses and 52% of overall water consumption. Water consumed for agriculture amounts to three times all other direct uses combined. Cattle feed crops including alfalfa and other grass hays account for 46% of all direct water consumption.
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    Quantifying The Linkages Between US' Water Resources And Its Production Of Food, Energy, And Water
    Ao, Yufei (Virginia Tech, 2023-05-25)
    Water is a critical resource that is essential for human well-being and economic development. Many regions around the world face ongoing water scarcity and competition over water resources. Climate change, other drastic social changes, and population and economic growth can significantly impact the supply and consumption of water. There has been an increasing body of research focusing on the Food-Energy-Water (FEW) nexus. There is a mismatch between the spatial resolution of data availability and the resolution that water resources follow. Lack of quality sub-county water data also makes the research of micro-level food-water dynamics difficult if not impossible. These challenges pose obstacles to the further understanding of water scarcity in the context of the FEW nexus and leaves critical gaps in the research of the nexus. In this dissertation I asked and answered the question: how do socio-economic forces shape localized groundwater depletion and surface water scarcity within the United States at the field and basin scale? Specifically, I tested whether irrigated farm size leads to reduction in groundwater application per unit area and whether an increase in the annual depletion in the underlying aquifer storage increases the probability of an irrigated land transfer, with a Kansas field level dataset and an econometrics approach. I estimated the FEW production and the water footprint of FEW production in every US watershed and compare the water footprint of production against their water scarcity. Then the groundwater reserves and dam storage in watersheds were examined as the buffers for the watersheds' FEW production against water shortages. I mapped the transfers of FEW goods and services and both the virtual and physical water flows from watersheds to US cities. The transportation infrastructure and other infrastructure that supports the FEW transfers are analyzed in terms of their contributions to the movement of FEW goods. This dissertation improves our understanding of how broad structural changes within the agricultural industry are interconnected with the overexploitation of groundwater resources. It is the first study of water footprint accounting with the most recent input data for the whole US food-energy-water system at the watershed level and includes an analysis of cities' infrastructure reliance for food-energy-water transfers and infrastructure as buffers. The transfers of virtual water and physical water were compared. The resulting data and findings from the novel data synthesis will provide insights for consumers, food companies, and other decision-makers at various levels on their connection to water resources in non-local areas. The outcomes of this dissertation will also improve our ability to analyze drivers and solutions to local small-scale watershed water scarcity challenges and allow a quantifiable basis for policy support in the water resources management domain and beyond.
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    Reducing water scarcity by improving water productivity in the United States
    Marston, Landon T.; Lamsal, Gambhir; Ancona, Zachary H.; Caldwell, Peter; Richter, Brian D.; Ruddell, Benjamin L.; Rushforth, Richard R.; Davis, Kyle Frankel (2020-09)
    Nearly one-sixth of U.S. river basins are unable to consistently meet societal water demands while also providing sufficient water for the environment. Water scarcity is expected to intensify and spread as populations increase, new water demands emerge, and climate changes. Improving water productivity by meeting realistic benchmarks for all water users could allow U.S. communities to expand economic activity and improve environmental flows. Here we utilize a spatially detailed database of water productivity to set realistic benchmarks for over 400 industries and products. We assess unrealized water savings achievable by each industry in each river basin within the conterminous U.S. by bringing all water users up to industry- and region-specific water productivity benchmarks. Some of the most water stressed areas throughout the U.S. West and South have the greatest potential for water savings, with around half of these water savings obtained by improving water productivity in the production of corn, cotton, and alfalfa. By incorporating benchmark-meeting water savings within a national hydrological model (WaSSI), we demonstrate that depletion of river flows across Western U.S. regions can be reduced on average by 6.2-23.2%, without reducing economic production. Lastly, we employ an environmentally extended input-output model to identify the U.S. industries and locations that can make the biggest impact by working with their suppliers to reduce water use 'upstream' in their supply chain. The agriculture and manufacturing sectors have the largest indirect water footprint due to their reliance on water-intensive inputs but these sectors also show the greatest capacity to reduce water consumption throughout their supply chains.
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    Retirement of US fossil fuel-fired power plants will increase water availability
    Siddik, Md Abu Bakar; Grubert, Emily; Caldwell, Peter; Marston, Landon T. (Elsevier, 2023-02)
    Nearly two-thirds of fossil fuel-fired electricity generation capacity in the United States is expected to reach its typical end of life by 2035. While the closure of fossil fuel-fired power plants will help advance decarbonization goals, the cessation of water use for fossil fuel-fired power plant cooling -the largest water user in the US -will also impact the nation's water resources. We assess when, where, and how much water will be made available upon the expected retirement of the nation's nearly one thousand fossil fuel-fired power plants by combining a lifespan-based model of fossil fuel-fired generator retirements for the US fossil fuel-fired electricity generation fleet with a national-scale hydrologic model. We show that annual water withdrawals and consumption of fossil fuel-fired power generators will be significantly curtailed (85 % and 68 % reduction, respectively) by 2035 if these generators follow their typical retirement timeline. Most rivers with fossil fuel-fired power plants diverting and/or discharging water will have a net increase in annual streamflow after plant retirement (maximum decrease of 2 %, maximum increase of 57 % by 2050), with the most pronounced increases occurring in the summer months. The retirement of fossil fuel-fired power plants will lead to a large relative change (>5%) in streamflow at least one month per year by 2050 in 31 subbasins. The retirement of power generators was shown to produce noticeable streamflow impacts up to hundreds of kilometers downstream. By the retirement of the last US fossil fuel-fired power generator, 2.6 billion m3 of water that was once consumed by these power plants could be made available for other uses. In addition to the global benefits of reduced greenhouse gas emissions, the notable increases in streamflow and water availability in many US rivers due to the retirement of fossil fuel-fired power plants could benefit local water users and ecosystems.
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    Survey of Groundwater Wells in the United States
    Miller, Alexandra Leigh (Virginia Tech, 2023-06-29)
    Groundwater wells are critical infrastructure with significant impacts on the environment, water availability, and economy. However, comprehensive data on the purposes, locations, depths, and construction of these wells are only collected by individual states. We have compiled a nationwide dataset of groundwater wells throughout the United States. The tabular dataset consists of all groundwater well data obtained from the states, containing over nine million records. A subset of this dataset was created that excludes wells located outside of the reported county or state, with over eight million records. Our dataset represents all known groundwater well locational data that states could release. The data made available by these datasets can serve as a critical tool for refining our understanding of how groundwater is accessed and used throughout the United States, and how it impacts different industries.
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    Understanding Data Science Instruction in Multiple STEM Disciplines
    Snyder, Caitlin; Asamen, Dawit M.; Naseri, Mohammad Y.; Aryal, Niroj; Biswas, Gautam; Dubey, Abhishek; Henrick, Erin; Hotchkiss, Erin R.; Jha, Manoj K.; Jiang, Steven X.; Kern, Emily C.; Lohani, Vinod K.; Marston, Landon T.; Vanags, Christopher P.; Xia, Kang (2021-07)
    As technology advances, data driven work is becoming increasingly important across all disciplines. Data science is an emerging field that encompasses a large array of topics including data collection, data preprocessing, data visualization, and data analysis using statistical and machine learning methods. As undergraduates enter the workforce in the future, they will need to “benefit from a fundamental awareness of and competence in data science”[9]. This project has formed a research practice partnership that brings together STEM+C instructors and researchers from three universities and an education research and consulting group. We aim to use high frequency monitoring data collected from real-world systems to develop and implement an interdisciplinary approach to enable undergraduate students to develop an understanding of data science concepts through individual STEM disciplines that include engineering, computer science, environmental science, and biology. In this paper, we perform an initial exploratory analysis on how data science topics are introduced into the different courses, with the ultimate goal of understanding how instructional modules and accompanying assessments can be developed for multidisciplinary use. We analyze information collected from instructor interviews and surveys, student surveys, and assessments from five undergraduate courses (243 students) at the three universities to understand aspects of data science curricula that are common across disciplines. Using a qualitative approach, we find commonalities in data science instruction and assessment components across the disciplines. This includes topical content, data sources, pedagogical approaches, and assessment design. Preliminary analyses of instructor interviews also suggest factors that affect the content taught and the assessment material across the five courses. These factors include class size, students’ year of study, students’ reasons for taking class, and students’ background expertise and knowledge. These findings indicate the challenges in developing data modules for multidisciplinary use. We hope that the analysis and reflections on our initial offerings has improved our understanding of these challenges, and how we may address them when designing future data science teaching modules. These are the first steps in a design-based approach to developing data science modules that may be offered across multiple courses.
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    Understanding the Limits of Residential Water Conservation through Generalized, Basin-Scale System Dynamics
    Winter, Benjamin Frederick (Virginia Tech, 2023-07-03)
    Population growth and climate change have strained existing water supplies requiring municipalities to shift towards demand management strategies to ensure reliable water provisions. Particularly in the residential sector, water conservation measures and incentives have been utilized to reduce demand during short-term shortages. As water conservation programs are now being commonly utilized as a way to ensure enough water will be available for continued growth, the impacts on a basin-wide scale have yet to be established. By changing the relative water demand for indoor and outdoor uses within a municipality, the amount of water being consumed can thereby reduce the effluent available for downstream communities. This research investigates how the timing of water conservation, water conservation strategy, and population growth impact water availability in a shared basin. A generalized system dynamics model reflecting typical residential water use and availability patterns similar to the southwest United States was utilized. We found that when upstream municipalities focus their initial reductions on non-consumptive demands, downstream municipalities reliant on upstream return flow have to increase their conservation rate to meet demands and maintain population growth. When most of the basin's population is in upstream municipalities, the more influence their change in water use has on downstream water availability. Therefore, consumptive conservation should be the priority of basin-wide conservation programs to ensure return flow is sufficient to satisfy the demands of downstream municipalities.
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    The Water Footprint of the United States
    Konar, Megan; Marston, Landon T. (MDPI, 2020-11-23)
    This paper commemorates the influence of Arjen Y. Hoekstra on water footprint research of the United States. It is part of the Special Issue “In Memory of Prof. Arjen Y. Hoekstra”. Arjen Y. Hoekstra both inspired and enabled a community of scholars to work on understanding the water footprint of the United States. He did this by comprehensively establishing the terminology and methodology that serves as the foundation for water footprint research. His work on the water footprint of humanity at the global scale highlighted the key role of a few nations in the global water footprint of production, consumption, and virtual water trade. This research inspired water scholars to focus on the United States by highlighting its key role amongst world nations. Importantly, he enabled the research of many others by making water footprint estimates freely available. We review the state of the literature on water footprints of the United States, including its water footprint of production, consumption, and virtual water flows. Additionally, we highlight metrics that have been developed to assess the vulnerability, resiliency, sustainability, and equity of sub-national water footprints and domestic virtual water flows. We highlight opportunities for future research.
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    Water-Use Data in the United States: Challenges and Future Directions
    Marston, Landon T.; Abdallah, Adel M.; Bagstad, Kenneth J.; Dickson, Kerim; Glynn, Pierre; Larsen, Sara G.; Melton, Forrest S.; Onda, Kyle; Painter, Jaime A.; Prairie, James; Ruddell, Benjamin L.; Rushforth, Richard R.; Senay, Gabriel B.; Shaffer, Kimberly (Wiley, 2022-05-10)
    In the United States, greater attention has been given to developing water supplies and quantifying available waters than determining who uses water, how much they withdraw and consume, and how and where water use occurs. As water supplies are stressed due to an increasingly variable climate, changing land-use, and growing water needs, greater consideration of the demand side of the water balance equation is essential. Data about the spatial and temporal aspects of water use for different purposes are now critical to long-term water supply planning and resource management. We detail the current state of water-use data, the major stakeholders involved in their collection and applications, and the challenges in obtaining high-quality nationally consistent data applicable to a range of scales and purposes. Opportunities to improve access, use, and sharing of water-use data are outlined. We cast a vision for a world-class national water-use data product that is accessible, timely, and spatially detailed. Our vision will leverage the strengths of existing local, state, and federal agencies to facilitate rapid and informed decision-making, modeling, and science for water resources. To inform future decision-making regarding water supplies and uses, we must coordinate efforts to substantially improve our capacity to collect, model, and disseminate water-use data.