Development of the finite-element-based Integrated Groundwater and Surface-Water Model (IGSM) began in the 1970s. Its popularity grew in the early 1990s with its application to California's Central Valley Groundwater Surface-Water Model in support of the Central Valley Project Improvement Act. Since that time, IGSM has been applied by federal, state, and local agencies to model a number of major basins in California. Our review of the recently released version 5.0 of IGSM reveals a solution methodology that deviates from established solution techniques, potentially compromising its reliability under many circumstances. One difficulty occurs because of the semi-explicit time discretization used. Combined with the fixed monthly time step of IGSM, this approach can prevent applications from accurately converging when using parameter values typically found in nature. Additionally, IGSM fails to properly couple and simultaneously solve ground water and surface water models with appropriate mass balance and head convergence under the reasonable conditions considered herein. As a result, IGSM-predicted streamflow is error prone, and errors could exceed 100%. IGSM does not inform the user that there may be a convergence problem with the solution, but instead generally reports good mass balance. Although our review touches on only a few aspects of the code, which exceeds 17,000 lines, our experience is that similar problems arise in other parts of IGSM. Review and examples demonstrate the potential consequences of using the solution methods in IGSM for the prediction, planning, and management of water resources, and provide perspective on the roles of standards and code validation in ground water modeling.
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http://dx.doi.org/10.1111/j.1745-6584.2003.tb02587.x | DOI Listing |
Environ Health Perspect
January 2025
Silent Spring Institute, Newton, Massachusetts, USA.
Background: Unregulated contaminants in drinking water, such as per- and polyfluoroalkyl substances (PFAS), can contribute to cumulative health risks, particularly in overburdened and less-advantaged communities. To our knowledge, there has been no nationwide assessment of socioeconomic disparities in exposures to unregulated contaminants in drinking water.
Objective: The goals of this study were to identify determinants of unregulated contaminant detection among US public water systems (PWSs) and evaluate disparities related to race, ethnicity, and socioeconomic status.
Environ Pollut
January 2025
Applied Geochemistry, Department of Civil, Environmental and Natural Resource Engineering, Luleå University of Technology, Luleå, Sweden.
Environ Monit Assess
January 2025
Institute of Environmental Engineering and Building Installations, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965, Poznan, Poland.
Riverbank filtration (RBF) has emerged as a crucial and functional water treatment method, particularly effective in improving surface water quality. This review is aimed at assessing the suitability of RBF in regions with limited access to clean water, such as Africa, where it has the potential to alleviate water scarcity and enhance water security. This review used various studies, highlighting the principles, applications, and advancements of RBF worldwide.
View Article and Find Full Text PDFJ Contam Hydrol
January 2025
Department of Computer Science, Instituto Nacional de Astrofísica, Optica y Electrónica, Luis Enrique Erro 1, Tonantzintla, 72840 Puebla, México; Consejo Nacional de Humanidades, Ciencias y Tecnologías (Conahcyt), Insurgentes Sur 1582, Mexico City 03940, Mexico. Electronic address:
This study addresses the critical challenge of assessing the quality of groundwater and surface water, which are essential resources for various societal needs. The main contribution of this study is the application of machine learning models for evaluating water quality, using a national database from Mexico that includes groundwater, lotic (flowing), lentic (stagnant), and coastal water quality parameters. Notably, no comparable water quality classification system currently exists.
View Article and Find Full Text PDFEnviron Int
January 2025
Département de Chimie, Université de Montréal, Montreal, QC, Canada. Electronic address:
This study investigated the occurrence of perfluoroalkyl and polyfluoroalkyl substances (PFAS), including anionic, cationic, and zwitterionic compounds, in drinking water. Between 2021-2023, an expanded list of 76 target PFAS was screened in tap water samples mainly from Canada, but also including tap water samples from the Eastern United States, Mexico, South America (Argentina), the Caribbean (Dominican Republic, Cuba), Africa (Algeria, Cameroon, Central African Republic, Morocco, Rwanda, Tunisia), Europe (France, Greece, Italy, Spain, and the United Kingdom) and Asia (Japan, Vietnam, Iran, and Türkiye). An additional ∼ 200 suspect-target PFAS were screened using high-resolution Orbitrap mass spectrometry.
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