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127 result(s) for "Water quality management United States History."
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Troubled water : what's wrong with what we drink
\"New York Times bestselling author Seth M. Siegel shows how our drinking water got contaminated, what it may be doing to us, and what we must do to make it safe\"-- Provided by publisher.
Karst waters in potable water supply: a global scale overview
Karst aquifers are one of the main potable water sources worldwide. Although the exact global karst water utilisation figures cannot be provided, this study represents an attempt to make an upgraded assessment of earlier and often circulated data. The main objective of the undertaken analysis is not only to provide an assessment of the utilisation of current karst aquifers, but also to estimate possible trends under various impact factors such as population growth or climate changes. In > 140 countries, different types of karstified rocks crop out over some 19.3 × 106 km2, covering > 14% of ice-free land. The main ‘karst countries’, those with > 1 × 106 km2 of karst surface are Russia, USA, China and Canada, while among those with > 80% of the territories covered by karst are Jamaica, Cuba, Montenegro and several others. In contrast, in a quarter of the total number of countries, karstic rocks are either totally absent or have a minor extension, meaning that no karst water sources can be developed. Although the precise number of total karst water consumers cannot be defined, it was assessed in 2016 at approximately 678 million or 9.2% of the world’s population, which is twice less than what was previously estimated in some of the reports. With a total estimated withdrawal of 127 km3/year, karst aquifers are contributing to the total global groundwater withdrawal by about 13%. However, only around 4% of the estimated average global annually renewable karstic groundwater is currently utilised, of which < 1% is for drinking purposes. Although often problematic because of unstable discharge regimes and high vulnerability to pollution, karst groundwater represents the main source of potable water supply in many countries and regions. Nevertheless, engineering solutions are often required to ensure a sustainable water supply and prevent negative consequences of groundwater over-extraction.
WASP 8: The Next Generation in the 50-year Evolution of USEPA’s Water Quality Model
The Water Quality Analysis Simulation Program (WASP) helps users interpret and predict water quality responses to natural phenomena and manmade pollution for various pollution management decisions. WASP is a dynamic compartment-modeling program for aquatic systems, including both the water column and the underlying benthos. WASP allows the user to investigate 1, 2 and 3 dimensional systems and a variety of pollutant types—including both conventional pollutants (e.g., dissolved oxygen, nutrients, phytoplankton, etc.) and toxic materials. WASP has capabilities of linking with hydrodynamic and watershed models which allows for multi-year analyses under varying meteorological and environmental conditions. WASP was originally developed by HydroScience, Inc. in 1970 and was later adapted by the US Environmental Protection Agency’s Large Lakes Research Station (LLRS) for applications to the Great Lakes. The LLRS first publicly released the model in 1981. WASP has undergone continuous development since that time and this year will mark its 50th anniversary. This paper follows the development of WASP from its origin to the latest release of the model in 2020, documenting its evolution and present structure and capabilities.
Reconstructing the good farmer identity: shifts in farmer identities and farm management practices to improve water quality
All farmers have their own version of what it means to be a good farmer. For many US farmers a large portion of their identity is defined by the high input, high output production systems they manage to produce food, fiber or fuel. However, the unintended consequences of highly productivist systems are often increased soil erosion and the pollution of ground and surface water. A large number of farmers have conservationist identities within their good farmer identity, however their conservation goals often need to be activated to rebalance the production-conservation meanings they give to their roles in society. In this paper we analyze US Cornbelt farmer interviews and surveys to trace how the performance-based environmental management process can be used to influence the farmer social identity and shift the overall good farmer identity towards a stronger conservationist standard. We find the continuous feedback loop in performance-based environmental management mimics the hierarchically organized feedback control processes of identity verification and can be used to help farmers activate their conservationist farmer identities at the person, role, and social levels to establish new norms for the practice of more sustainable agriculture.
Prioritizing water availability study settings to address geogenic contaminants and related societal factors
Water availability for human and ecological uses depends on both water quantity and water quality. The U.S. Geological Survey (USGS) is developing strategies for prioritizing regional-scale and watershed basin-scale studies of water availability across the nation. Previous USGS ranking processes for basin-scale studies incorporated primarily water quantity factors but are now considering additional water quality factors. This study presents a ranking based on the potential impacts of geogenic constituents on water quality and consideration of societal factors related to water quality. High-concentration geogenic constituents, including trace elements and radionuclides, are among the most prevalent contaminants limiting water availability in the USA and globally. Geogenic constituents commonly occur in groundwater because of subsurface water–rock interactions, and their distributions are controlled by complex geochemical processes. Geogenic constituent mobility can also be affected by human activities (e.g., mining, energy production, irrigation, and pumping). Societal factors and relations to drinking water sources and water quality information are often overlooked when evaluating research priorities. Sociodemographic characteristics, data gaps resulting from historical data-collection disparities, and infrastructure condition/age are examples of factors to consider regarding environmental justice. This paper presents approaches for ranking and prioritizing potential basin-scale study areas across the contiguous USA by considering a suite of conventional physical and geochemical variables related to geogenic constituents, with and without considering variables related to societal factors. Simultaneous consideration of societal and conventional factors could provide decision makers with more diverse, interdisciplinary tools to increase equity and reduce bias in prioritizing focused research areas and future water availability studies.
Evaluation of water-level trends in the Mimbres Basin, southwest New Mexico (USA), using spatiotemporal kriging
Groundwater-level trends over the past 40 years in the Mimbres Basin of southwest New Mexico (USA) were characterized with sequential water-level maps and maps of water-level change generated via spatiotemporal kriging. In the region of the most abundant irrigated agriculture, water levels have declined up to 24 m and cones of depression have expanded greatly. Increases in area of irrigated land and groundwater withdrawals in the past 10 years are coeval with water-level declines near the USA-Mexico border. Known areas of groundwater recharge from streamflow infiltration, and springs discharging deep-sourced water, show evidence of net water-level rises in the past 40 years, but declines in the last 10 years, in concert with declining precipitation over the basin. Formerly irrigated lands exhibit water-level rises, suggestive of flattening of cones of depression after cessation of extensive groundwater pumping. Manual water-level measurements are vital for understanding and managing groundwater resources, yet they are expensive and laborious to collect, which has resulted in much fewer data in recent years. Spatiotemporal kriging is more complex in mathematical development and implementation than spatial kriging, but it yields improved precision and accuracy, predictions at times with no data as well as at locations with no data, and fewer artifacts due to changing well networks. Its ability to leverage historical data recommends its use in hydrologic studies dependent on water-level maps and changes in water levels over time.
The Social, Historical, and Institutional Contingencies of Dam Removal
Environmental managers in the United States and elsewhere are increasingly perceiving dam removal as a critical tool for river restoration and enhancing watershed resilience. In New England, over 125 dams have been dismantled for ecological and economic rationales. A surprising number of these removals, including many that are ongoing, have generated heated conflicts between restoration proponents and local communities who value their dammed landscapes. Using a comparative case study approach, we examine the environmental conflict around efforts to remove six dams in New England. Each of these removal efforts followed quite different paths and resultant outcomes: successful removal, stalled removal, and failure despite seemingly favorable institutional conditions. Lengthy conflicts often transpired in instances where removals occurred, but these were successfully arbitrated by paying attention to local historical–geographical conditions conducive to removal and by brokering effective compromises between dam owners and the various local actors and stakeholders involved in the removal process. Yet our results across all cases suggest that these are necessary, but not sufficient conditions for restoration through dam removal since a similar set of conditions typified cases where removals are continuously stalled or completely halted. Scholars examining the intersection between ecological restoration and environmental politics should remain vigilant in seeking patterns and generalities across cases of environmental conflict in order to promote important biophysical goals, but must also remain open to the ways in which those goals are thwarted and shaped by conflicts that are deeply contingent on historical–geographical conditions and broader institutional networks of power and influence.
Iowa Stream Nitrate, Discharge and Precipitation: 30-Year Perspective
We evaluated Iowa Department of Natural Resources nitrate (NO3–N) and US Geological Survey hydrological data from 1987 to 2016 in nine agricultural watersheds to assess how transport of this pollutant has changed in the US state of Iowa. When the first 15 years of the 30-year water-quality record is compared to the second 15 years (1987–2001 and 2002–2016), three different metrics used to quantify NO3–N transport all indicate levels of this pollutant are increasing. Yield of NO3–N (kg ha−1) averaged 18% higher in the second 15 years, while flow-weighted average concentrations (mg L−1) were 12% higher. We also introduced the new metric of NO3–N yield (g ha−1) per mm precipitation to assess differences between years and watersheds, which averaged 21 g NO3–N ha−1 per 1 mm of precipitation across all watersheds and was 13% higher during the second half of the record. These increases of NO3–N occurred within a backdrop of increasing wetness across Iowa, with precipitation and discharge levels 8 and 16% higher in the last half of the record, indicating how NO3–N transport is amplified by increasing precipitation levels. The implications of this are that in future climate scenarios where rainfall is more abundant, detaining water and increasing evapotranspiration within the cropping system will be necessary to control NO3–N losses. Land use changes that include use of cover crops, living mulches, and perennial plants should be expanded to improve water quality and affect the water balance within agricultural basins.
Seasonal manganese transport in the hyporheic zone of a snowmelt-dominated river (East River, Colorado, USA)
Manganese (Mn) plays a critical role in river-water quality because Mn-oxides serve as sorption sites for contaminant metals. The aim of this study is to understand the seasonal cycling of Mn in an alpine streambed that experiences large spring snowmelt events and the potential responses to changes in snowmelt timing and magnitude. To address this goal, annual variations in river-water/groundwater interaction and Mn(aq) transport were measured and modeled in the bed of East River, Colorado, USA. In observations and numerical models, oxygenated river water containing dissolved organic carbon (DOC) mixes with groundwater rich in Mn(aq) in the streambed. The mixing depth increases during spring snowmelt when river discharge increases, leading to a greater DOC supply to the hyporheic zone and net respiration of Mn-oxides, despite an enhanced supply of oxygen. As groundwater upwelling resumes during the subsequent baseflow period, Mn(aq)-rich groundwater mixes with oxygenated river water, resulting in net accumulation of Mn-oxides until the bed freezes in winter. To explore potential responses of Mn transport to different climate-induced hydrological regimes, three hydrograph scenarios were numerically modeled (historic, low-snow, and storm) for the Rocky Mountain region. In a warming climate, Mn(aq) export to the river decreases, and Mn(aq) oxidation is favored in the upper streambed sediments over more of the year. One important implication is that the streambed may have an increased sorption capacity for metals over more of the year, leading to potential changes in river-water quality.
Applications of polychlorinated biphenyls
Background, aim, and scope In the 50 years or so that polychlorinated biphenyls (PCBs) were manufactured in the USA and elsewhere, they were widely used in numerous applications because of their desirable properties. The purpose of this paper is to review and summarize in one place the factual information about the uses of PCBs, as well as to correct some misconceptions that have arisen over the years. The focus is on applications in the USA for which there is ample documentation. However, use patterns were probably similar worldwide. Materials and methods Review. Results PCBs were used primarily as electrical insulating fluids in capacitors and transformers and also as hydraulic, heat transfer, and lubricating fluids. PCBs were blended with other chemicals as plasticizers and fire retardants and used in a range of products including caulks, adhesives, plastics, and carbonless copy paper. In the USA, PCBs were manufactured from 1929 through mid-1977, although many products remained in service for decades after the manufacture of PCBs was terminated. This article reviews the historic uses of PCBs in the USA and discusses, where possible, the relative sales volumes. Especially with smaller volume, military, and third-party uses, documenting a use and/or differentiating between a commercial use and an experimental test batch is not possible. Discussion A major contribution of this paper is to differentiate reported commercial applications of PCBs that can be documented from those which cannot. Undocumented uses may include actual minor uses as well as reported applications that are unlikely ever to have been commercialized.