Research Papers: Water Systems

Does water scarcity shift the electricity generation mix toward fossil fuels? Empirical evidence from the United States

By Jonathan Eyer, Casey Wichman

Journal of Environmental Economics and Management 87

2018

Water withdrawals for the energy sector are the largest use of fresh water in the United States. Using an econometric model of monthly plant-level electricity generation levels between 2001 and 2012, we estimate the effect of water scarcity on the US electricity fuel mix. We find that hydroelectric generation decreases substantially in response to drought, although this baseline generation is offset primarily by natural gas, depending on the geographic region. We provide empirical evidence that drought can increase emissions of CO2 and local pollutants. We quantify the social costs of water scarcity to be $330,000 per month for each plant that experiences a one-standard deviation increase in water scarcity (2015 dollars), a relationship that persists under future projections of water scarcity.


Water Use in the United States Energy System: A National Assessment and Unit Process Inventory of Water Consumption and Withdrawals

By Kelly T. Sanders, Emily Grubert

Environmental Science & Technology

2018

The United States (US) energy system is a large water user, but the nature of that use is poorly understood. To support resource comanagement and fill this noted gap in the literature, this work presents detailed estimates for US-based water consumption and withdrawals for the US energy system as of 2014, including both intensity values and the first known estimate of total water consumption and withdrawal by the US energy system. We address 126 unit processes, many of which are new additions to the literature, differentiated among 17 fuel cycles, five life cycle stages, three water source categories, and four levels of water quality. Overall coverage is about 99% of commercially traded US primary energy consumption with detailed energy flows by unit process. Energy-related water consumption, or water removed from its source and not directly returned, accounts for about 10% of both total and freshwater US water consumption. Major consumers include biofuels (via irrigation), oil (via deep well injection, usually of nonfreshwater), and hydropower (via evaporation and seepage). The US energy system also accounts for about 40% of both total and freshwater US water withdrawals, i.e., water removed from its source regardless of fate. About 70% of withdrawals are associated with the once-through cooling systems of approximately 300 steam cycle power plants that produce about 25% of electricity.


Performance analysis of statistical spatial measures for contaminant plume characterization toward risk‐based decision making

By Francesca Boso, Felipe de Barros, A. Fiori, A. Bellin

Water Resources Research

2013

The spatial distribution of solute concentration in heterogeneous aquifers is extremely complex and variable over scales ranging from a few millimeters to kilometers. Obtaining a detailed spatial distribution of the concentration field is an elusive goal because of intrinsic technical limitations and budget constraints for site characterization. Therefore, local concentration predictions are highly uncertain and alternative measures of transport must be sought. In this paper, we propose to describe the spatial distribution of the concentrations of a nonreactive tracer plume by means of suitable spatial statistical transport measures, as an alternative to approaches relying only on the ensemble mean concentration. By assuming that the solute concentration is statistically distributed according to the Beta distribution model, we compare several models of concentration moments against numerical simulations and Cape Cod concentration data. These measures provide useful information which are: (i) representative of the overall transport process, (ii) less affected by uncertainty than the local probability density function and (iii) only marginally influenced by local features. The flexibility of the approach is shown by considering three different integral expressions for both the spatial mean and variance of concentration based on previous works. Aiming at a full statistical characterization, we illustrate how the Beta relative cumulative frequency distribution (obtained as a function of the spatial concentration) compares with the numerical cumulative frequencies. Our approach allows to estimate the probability of exceeding a given concentration threshold within the computational or observational domain, which could be used for sampling data campaigns, preliminary risk assessment and model refinement. Finally, our results highlight the importance of goal‐oriented model development.


A risk‐based probabilistic framework to estimate the endpoint of remediation: Concentration rebound by rate‐limited mass transfer

By Felipe de Barros, D. Fernandez-Garcia, D. Bolster, X. Sanchez-Vila

Water Resources Research

2013

Aquifer remediation is a challenging problem with environmental, social, and economic implications. As a general rule, pumping proceeds until the concentration of the target substance within the pumped water lies below a prespecified value. In this paper we estimate the a priori potential failure of the endpoint of remediation due to a rebound of concentrations driven by back diffusion. In many cases, it has been observed that once pumping ceases, a rebound in the concentration at the well takes place. For this reason, administrative approaches are rather conservative, and pumping is forced to last much longer than initially expected. While a number of physical and chemical processes might account for the presence of rebounding, we focus here on diffusion from low water mobility into high mobility zones. In this work we look specifically at the concentration rebound when pumping is discontinued while accounting for multiple mass transfer processes occurring at different time scales and parametric uncertainty. We aim to develop a risk‐based optimal operation methodology that is capable of estimating the endpoint of remediation based on aquifer parameters characterizing the heterogeneous medium as well as pumping rate and initial size of the polluted area.


The disappearing Salton Sea: A critical reflection on the emerging environmental threat of disappearing saline lakes and potential impacts on children’s health.

By Jill E. Johnston, Mitiasoa Razafy, Humberto Lugo, Luis Olmedo, Shohreh F. Farzan

Science of the Total Environment

2019

Changing weather patterns, droughts and competing water demands are dramatically altering the landscape and creating conditions conducive to the production of wind-blown dust and dust storms. In California, such factors are leading to the rapid shrinking of the Salton Sea, a 345 mile2 land-locked “sea” situated near the southeastern rural border region known as the Imperial Valley. The region is anticipated to experience a dramatic increase in wind-blown dust and existing studies suggest a significant impact on the health and quality of life for nearby residents of this predominantly low-income, Mexican-American community. The discussion calls attention to the public health dimensions of the Salton Sea crisis. We know little about the possible long-term health effects of exposure to mobilized lakebed sediments or the numerous toxic contaminants that may become respirable on entrained particles. We draw on existing epidemiological literature of other known sources of wind-blown dust, such as desert dust storms, and related health effects to begin to understand the potential public health impact of wind-blown dust exposure. The increased production of wind-blown dust and environmental exposures to such non-combustion related sources of particulate matter are a growing health threat, due in part to drought coupled with increasing pressures on limited water resources. Recent population-based studies have linked dust storms with cardiovascular mortality, asthma hospitalization and decrease in pulmonary function in both adults and children. A growing number of studies provide evidence of the acute health effects of wind-blown dust exposures among children, which with repeated insults have the potential to influence respiratory health over time. The shrinking of the Salton Sea illustrates a public health and environmental justice crisis that requires action and attention to protect the health and well-being of local communities.


The spoils of dust: reinventing the lake that made Los Angeles

By Alexander Robinson

Novato California : Applied Research and Design Publishing, an imprint of ORO Editions

2018

Once the third largest lake in California, and among the world’s greatest air pollution offenders, the deadened Owens Lake was for decades merely a catastrophic footnote to the most notorious water grab in modern history. Now, the lake has been re-assembled to exceed the value of what was lost – without refilling its shores and depriving Los Angeles of its water supply. In ‘The spoils of dust’ the lake’s peculiar redemption is the backdrop for investigating contemporary relationships between landscape design, control, and perception. The lake-like terrain is our most intimate display of modern technocratic vision and exposes the limits of our invention and control of infrastructural ecologies. Whether by observations of dust or scenery, it is as much the product of how we perceive and value landscape today. Answering its analysis, the book concludes with a visual atlas and proposal to induce more imaginative outcomes and perceptions.


Willful Waters

By Vittoria de Palma, Alexander Robinson

Places Journal

2018


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