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At least 19 recordsLinked to original sources
USGS1975

An empirical note on firm performance in government contract markets

Public construction and, in particular, highway construction account for a large proportion of the non-defense expenditures by the government. Con- tracts for highway construction are let almost exclusively through a sealed tender process. Competitive bidding is used to encourage price competition. There is, however, a problem in insuring that the bidder is able to deliver the product of specified quality and within a particular time period. Hence, in regulating such markets for product performance the bidding authority may wish to exclude bidders who cannot demonstrate that they are qualified to perform the specified service. In this paper, data from state highway departments are used to indicate the consequences of such exclusive policies in terms of market performance. The results obtained are consistent with traditional theory and present an interesting addition to the more specialized literature on participation of private firms in government markets.

The Journal of Industrial Economics↗
USGS1997

Rare-earth metal prices in the USA ca. 1960 to 1994

Rare-earth metal prices were compiled from the late 1950s and early 1960s through 1994. Although commercial demand for rare-earth metals began in 1908, as the alloy mischmetal, commercial quantities of a wide range of individual rare-earth metals were not available until the late 1950s. The discovery of a large, high-grade rare-earth deposit at Mountain Pass, CA, USA, in 1949, was significant because it led to the production of commercial quantities of rare-earth elements that reduced prices and encouraged wider application of the materials. The availability of ore from Mountain Pass, and other large rare-earth deposits, especially those in Australia and China, has provided the world with abundant resources for rare-earth metal production. This availability, coupled with improved technology from Government and private-sector metallurgical research, has resulted in substantial decreases in rare-earth metal prices since the late 1950s and early 1960s. Price series for the individual rare-earth metals (except promethium) are quoted on a kilogram basis from the late 1950s and early 1960s through 1994. Prices are given in US dollars on an actual and constant dollar basis. Industrial and economic factors affecting prices during this time period are examined.

Journal of Alloys and Compounds↗
USGS1987

Economics of the coal industry east of the Mississippi, 1973-1982

Government regulations on health, safety and environment have been poppular blamed for the declining productivity in U.S. coal mines since 1970. The stagnation in the coal industry east of the Mississippi is alleged to have been caused by this declining productivity and by the growth of cheaper and cleaner coal production west of the Mississippi. Economic evidence suggests, however, that productivity declines were more due to a relative lowering of labor costs in comparison with coal prices and due to work stoppages. The development of western coals fields was spurred by growth in local demand and had only a relatively small impact on coal production east of the Mississippi. Problems of the eastern coal industry are rooted mainly in slow economic growth in eastern U.S. which must be addressed in the long-term interests of the eastern coal industry.

International Journal of Coal Geology↗
USGS1984

Economics and appraisal of conventional oil and gas resources in the western Gulf of Mexico

The oil and gas industry frequently appraises undiscovered oil and gas resources on a regional basis to decide whether to start or continue exploration programs. The appraisals are of little value unless conditioned by estimates of the costs of finding and producing the resources. This paper presents an economic appraisal of undiscovered oil and presents an economic appraisal of undiscovered oil and gas resources in the western Gulf of Mexico. Also presented are a description of the model used to make the presented are a description of the model used to make the assessment, results of a sensitivity analysis, and a discussion of the implications of the results to the industry. The appraisal is shown to be relatively robust to changes in physical and engineering assumptions. At $30/bbl [$4.76/m ] oil equivalent (OE) and a 15 % required rate of return (ROR), commercial oil and gas discoveries are expected to amount to about 15 % of the 25.19 × 10 bbl [4 × 10 m ] OE contained in fields discovered before 1977 in the studied area. Hydrocarbons in future discoveries are expected to be 71 % nonassociated gas, 17 % crude oil, and 12 % other forms. Moreover, it will continue to be economically optimal to drill about three wildcat wells in the Miocene-Pliocene trend for every wildcat well drilled in the Pleistocene trend. Because the number of commercial discoveries was found to be quite sensitive to economic conditions, the analysis has important implications in terms of forecasting future industry drilling and other associated activities in the western Gulf of Mexico.

Journal of Petroleum Technology↗
USGS2020

Eastern oyster clearance and respiration rates in response to acute and chronic exposure to suspended sediment loads

Coastal Louisiana supports some of the most productive areas for the eastern oyster, Crassostrea virginica . Changing conditions from restoration and climate change alter freshwater and sediment inflows into critical estuarine areas affecting water quality, including salinity and concentrations of suspended sediment. This study examined the effects of acute (1 h) and chronic (8 weeks) exposure of suspended sediment concentrations on the eastern oyster's respiration and clearance rates. Acute exposure at six sediment concentrations (0, 10, 50, 200, 500, 1000 mg L −1 ) and one salinity (15) indicated that sediment concentration significantly affected oyster clearance rates, with increasing clearance rates as suspended sediment concentrations increased up to 500 mg L −1 . Respiration rates were not affected by sediment concentration ( p = .12). Chronic exposure at two salinities (6 and 15) and three sediment concentrations (0, 50, 400 mg L −1 ) found no significant effect of sediment, salinity or their interaction on clearance rates. Respiration rate was reduced at higher sediment concentrations (50 and 400 mg L −1 versus 0 mg L −1 ) and lower salinity. As clearance and oxygen consumption rates critically inform oyster energetic models, these data provide valuable insight to more accurately predict eastern oyster population dynamics and inform harvest models in the face of changing estuarine conditions. Changes in rates of growth through altered energetic demands ultimately can impact not just the economic viability of the industry, but also the ability for the populations to maintain sustainable reefs.

Louisiana↗
USGS2011

Consequences of increasing bioenergy demand on wood and forests: An application of the Global Forest Products Model

The Global Forest Products Model (GFPM) was applied to project the consequences for the global forest sector of doubling the rate of growth of bioenergy demand relative to a base scenario, other drivers being maintained constant. The results showed that this would lead to the convergence of the price of fuelwood and industrial roundwood, raising the price of industrial roundwood by nearly 30% in 2030. The price of sawnwood and panels would be 15% higher. The price of paper would be 3% higher. Concurrently, the demand for all manufactured wood products would be lower in all countries, but the production would rise in countries with competitive advantage. The global value added in wood processing industries would be 1% lower in 2030. The forest stock would be 2% lower for the world and 4% lower for Asia. These effects varied substantially by country. ?? 2011 Department of Forest Economics, SLU Ume??, Sweden.

Journal of Forest Economics↗
USGS1985

Lognormal field size distributions as a consequence of economic truncation

The assumption of lognormal (parent) field size distributions has for a long time been applied to resource appraisal and evaluation of exploration strategy by the petroleum industry. However, frequency distributions estimated with observed data and used to justify this hypotheses are conditional. Examination of various observed field size distributions across basins and over time shows that such distributions should be regarded as the end result of an economic filtering process. Commercial discoveries depend on oil and gas prices and field development costs. Some new fields are eliminated due to location, depths, or water depths. This filtering process is called economic truncation. Economic truncation may occur when predictions of a discovery process are passed through an economic appraisal model. We demonstrate that (1) economic resource appraisals, (2) forecasts of levels of petroleum industry activity, and (3) expected benefits of developing and implementing cost reducing technology are sensitive to assumptions made about the nature of that portion of (parent) field size distribution subject to economic truncation. ?? 1985 Plenum Publishing Corporation.

Journal of the International Association for Mathe↗
USGS1980

An econometric model of the U.S. secondary copper industry: Recycling versus disposal

In this paper, a theoretical model of secondary recovery is developed that integrates microeconomic theories of production and cost with a dynamic model of scrap generation and accumulation. The model equations are estimated for the U.S. secondary copper industry and used to assess the impacts that various policies and future events have on copper recycling rates. The alternatives considered are: subsidies for secondary production, differing energy costs, and varying ore quality in primary production.

Journal of Environmental Economics and Management↗
USGS2016

INVASIVESNET towards an International Association for Open Knowledge on Invasive Alien Species

In a world where invasive alien species (IAS) are recognised as one of the major threats to biodiversity, leading scientists from five continents have come together to propose the concept of developing an international association for open knowledge and open data on IAS—termed “INVASIVESNET”. This new association will facilitate greater understanding and improved management of invasive alien species (IAS) and biological invasions globally, by developing a sustainable network of networks for effective knowledge exchange. In addition to their inclusion in the CBD Strategic Plan for Biodiversity, the increasing ecological, social, cultural and economic impacts associated with IAS have driven the development of multiple legal instruments and policies. This increases the need for greater co-ordination, co-operation, and information exchange among scientists, management, the community of practice and the public. INVASIVESNET will be formed by linking new and existing networks of interested stakeholders including international and national expert working groups and initiatives, individual scientists, database managers, thematic open access journals, environmental agencies, practitioners, managers, industry, non-government organisations, citizens and educational bodies. The association will develop technical tools and cyberinfrastructure for the collection, management and dissemination of data and information on IAS; create an effective communication platform for global stakeholders; and promote coordination and collaboration through international meetings, workshops, education, training and outreach. To date, the sustainability of many strategic national and international initiatives on IAS have unfortunately been hampered by time-limited grants or funding cycles. Recognising that IAS initiatives need to be globally coordinated and ongoing, we aim to develop a sustainable knowledge sharing association to connect the outputs of IAS research and to inform the consequential management and societal challenges arising from IAS introductions. INVASIVESNET will provide a dynamic and enduring network of networks to ensure the continuity of connections among the IAS community of practice, science and management.

Management of Biological Invasions↗
USGS1975

Phosphate fertilizer materials in Colombia; imports, uses, and domestic supplies

The distribution of potentially economic phosphate deposits and the locations of major users of phosphate products in Colombia are some of the economic factors that indicate the capability of the deposits to supply domestic demands. Much research is required to determine the types of processing plants needed and to outline changes from standard procedures, but there is little doubt that with proper planning a phosphate chemical industry could be developed that would supply domestic demands for the forseeable future.

Journal of Research of the U.S. Geological Survey↗
USGS2018

Genetic evidence supports sporadic and independent introductions of subtype H5 low pathogenic avian influenza A viruses from wild birds to domestic poultry in North America

Wild bird–origin influenza A viruses (IAVs or avian influenza) have led to sporadic outbreaks among domestic poultry in the United States (US) and Canada, resulting in economic losses through the implementation of costly containment practices and destruction of birds. We used evolutionary analyses of virus sequence data to determine that 78 H5 low pathogenic avian influenza viruses (LPAIVs) isolated from domestic poultry in the US and Canada during 2001–2017 resulted from 18 independent virus introductions from wild birds. Within the wild bird reservoir, the hemagglutinin gene segments of H5 LPAIVs exist primarily as two co-circulating genetic sublineages, and our findings suggest the H5 gene segments flow within each migratory bird flyway and among adjacent flyways, with limited exchange between the non-adjacent Atlantic and Pacific Flyways. Phylogeographic analyses provided evidence that IAVs from dabbling ducks and swans/geese contributed to emergence of viruses among domestic poultry. H5 LPAIVs isolated from commercial farm poultry (i.e. turkey) were descended from a single introduction typically remain a single genotype, whereas those from live bird markets sometimes led to multiple genotypes, reflecting the potential for reassortment with other IAVs circulating within live bird markets. H5 LPAIV introduced from wild birds to domestic poultry represent economic threats to the U.S. poultry industry, and our data suggest that such introductions have been sporadic, controlled effectively through production monitoring and a stamping-out policy, and are, therefore, unlikely to result in sustained detections in commercial poultry operations.

Journal of Virology↗
USGS2024

Understanding key mineral supply chain dynamics using economics-informed material flow analysis and Bayesian optimization

The low-carbon energy transition requires significant increases in production for many mineral commodities. Understanding demand, technological requirements, and prices associated with this production increase requires understanding the supply chain dynamics of many minerals simultaneously, and via a consistent framework. A generalized economics-informed material flow method, global materials modeling using Bayesian optimization, captures the market dynamics of key mineral commodities. The method relies only on a limited set of widely available historical data as input, enabling quantification of economic relationships (elasticities) for supply chain components where data are sparse, and relationships cannot be obtained via traditional statistical approaches. Building upon established material flow analysis (MFA) and economic modeling techniques, Bayesian optimization was applied to fit an economics-informed MFA model to global historical demand, supply, and price for aluminum, copper, gold, lead, nickel, silver, iron, tin, and zinc. This approach enables estimates for the evolution of ore grades, mine costs, refining charges, sector-specific demand, and scrap collection for each commodity. Economic relationships were quantified and compared with a database compiled from the literature, including 1333 values from 213 analyses across 65 publications. Discrepancies in methods and limited coverage make use of these parameters in modeling efforts difficult. This work provides a single, homogeneous, probabilistic approach to identifying economic relationships across mineral supply chains, with uncertainty quantification, a literature database for comparison, and a modeling framework in which to use them. This article met the requirements for a Gold-Gold JIE data openness badge described at http://jie.click/badges .

Journal of Industrial Ecology↗
USGS2006

Temporal variations of heavy metals in coral Porites lutea from Guangdong Province, China: Influences from industrial pollution, climate and economic factors

The eight heavy metals Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb have been determined in samples of coral Porites lutea collected from Dafangji Island waters (21°21′N, 111°11′E), Dianbai County, Guangdong Province, China, by the ICP-MS method. The samples represent the growth of coral in the period of 1982–2001. The results showed that the waters were polluted by the heavy metals Cu, Ni, Zn, and Pb in certain years, but not by other metals. The contamination may have come from industrial sources, including electroplating, metallurgy, mining, and aquatic industries in the coastal areas. The correlation coefficients among the metals and climatic and economic factors indicate that the metals Ni, Zn, and Cd behave similarly. Copper and Mn are positively correlated, and cobalt is negatively correlated with Cr, Ni, Zn, and Cd. Lead is not correlated with any other metals but is correlated with sea surface water temperature, air temperature, GDP and industrial-agricultural production in Dianbai County. Lead in corals is related to the enhanced pollution level of ocean waters as a result of increased industrial activities.

Chinese Journal of Geochemistry↗
USGS2006

Metallogeny of the Great Basin: Crustal evolution, fluid flow, and ore deposits

The Great Basin physiographic province in the Western United States contains a diverse assortment of world-class ore deposits. It currently (2006) is the world’s second leading producer of gold, contains large silver and base metal (Cu, Zn, Pb, Mo, W) deposits, a variety of other important metallic (Fe, Ni, Be, REE’s, Hg, PGE) and industrial mineral (diatomite, barite, perlite, kaolinite, gallium) resources, as well as petroleum and geothermal energy resources. Ore deposits are most numerous and largest in size in linear mineral belts with complex geology. U.S. Geological Survey (USGS) scientists are in the final year of a research project initiated in the fall of 2001 to increase understanding of relations between crustal evolution, fluid flow, and ore deposits in the Great Basin. Because of its substantial past and current mineral production, this region has been the focus of numerous investigations over the past century and is the site of ongoing research by industry, academia, and state agencies. A variety of geoinformatic tools was used to organize, reinterpret, and display, in space and time, the large amounts of geologic, geophysical, geochemical, and hydrologic information deemed pertinent to this problem. This information, in combination with concentrated research on (1) critical aspects of the geologic history, (2) an area in northern Nevada that encompasses the major mineral belts, and (3) important mining districts and deposits, is producing new insights about the interplay between key tectonic events, hydrothermal fluid flow, and ore genesis in mineral belts. The results suggest that the Archean to Holocene history of the Great Basin was punctuated by several tectonic events that caused fluids of different origins (sea water, basinal brine, meteoric water, metamorphic water, magmatic water) to move through the crust. Basement faults reactivated during these events localized deformation, sedimentation, magmatism, and hydrothermal fluid flow in overlying rocks to form mineral belts that contain ore deposits of different types and ages that are locally superimposed (demonstrating inheritance). Fluid flow in these systems also was influenced by the distribution of permeable lithologies and paleotopographic highs and lows. Hydrothermal fluids evolved from their initial chemistries towards compositions that reflect the ƒ O 2 and ƒ S 2 buffering capacity of, and the ligands and metals present in, the rocks (±older mineralization) through which they moved. In northern Nevada, where gold deposits are relatively common, carbonaceous, pyritic strata buffered fluids of diverse origins to H 2 S-rich compositions so they could transport gold repeatedly over Paleozoic-Cenozoic time (convergent evolution). Ore formed where metal-laden fluids encountered effective physicochemical traps. Maps of Neogene basin fill and erosion surfaces identify areas where preexisting ore deposits have been progressively exposed or concealed. Comparisons with analogous terrains and deposit types in other parts of the world provide global context. The initial findings and some of the databases, geologic maps, sections, reconstructions, hydrogeologic models, topical syntheses, regional overviews, short courses, field guides, and deposit comparisons produced by project staff and associated managers, contractors, and collaborators have been presented in numerous abstracts, symposia, USGS publications, and professional journals over the last 5 years (see the extensive bibliography). Notable among these was the 2005 Geological Society of Nevada symposium in Reno, Nevada, and the 2005 Geological Society of America annual meeting in Salt Lake City, Utah, where project results were presented to audiences from around the nation and world. The final results of the project will be submitted for publication in 2007 to appropriate USGS and professional journals. A special issue of GEOSPHERE, scheduled for publication in 2007, will be devoted to the results of this project and related work. This special issue will reach an international audience and be available worldwide on the internet. Much of the research for this project has concentrated on areas that will receive the focused attention of the mining industry in the future. As such, the data and interpretations generated by this project have direct use for land-use managers in Federal, State, and local agencies. Improved hydrogeologic models developed by this project will considerably enhance ongoing and future water resource investigations in the region. The increased understanding of when, where, and how hydrothermal systems produce significant economic deposits has direct uses for mineral exploration and for future USGS mineral resource assessments in the Great Basin and other parts of the world.

Great Basin↗
USGS2016

Managing adaptively for multifunctionality in agricultural systems

The critical importance of agricultural systems for food security and as a dominant global landcover requires management that considers the full dimensions of system functions at appropriate scales, i.e. multifunctionality. We propose that adaptive management is the most suitable management approach for such goals, given its ability to reduce uncertainty over time and support multiple objectives within a system, for multiple actors. As such, adaptive management may be the most appropriate method for sustainably intensifying production whilst increasing the quantity and quality of ecosystem services. However, the current assessment of performance of agricultural systems doesn’t reward ecosystem service provision. Therefore, we present an overview of the ecosystem functions agricultural systems should and could provide, coupled with a revised definition for assessing the performance of agricultural systems from a multifunctional perspective that, when all satisfied, would create adaptive agricultural systems that can increase production whilst ensuring food security and the quantity and quality of ecosystem services. The outcome of this high level of performance is the capacity to respond to multiple shocks without collapse, equity and triple bottom line sustainability. Through the assessment of case studies, we find that alternatives to industrialized agricultural systems incorporate more functional goals, but that there are mixed findings as to whether these goals translate into positive measurable outcomes. We suggest that an adaptive management perspective would support the implementation of a systematic analysis of the social, ecological and economic trade-offs occurring within such systems, particularly between ecosystem services and functions, in order to provide suitable and comparable assessments. We also identify indicators to monitor performance at multiple scales in agricultural systems which can be used within an adaptive management framework to increase resilience at multiple scales.

Journal of Environmental Management↗
USGS2011

The human dimension of fire regimes on Earth

Humans and their ancestors are unique in being a fire‐making species, but ‘natural’ (i.e. independent of humans) fires have an ancient, geological history on Earth. Natural fires have influenced biological evolution and global biogeochemical cycles, making fire integral to the functioning of some biomes. Globally, debate rages about the impact on ecosystems of prehistoric human‐set fires, with views ranging from catastrophic to negligible. Understanding of the diversity of human fire regimes on Earth in the past, present and future remains rudimentary. It remains uncertain how humans have caused a departure from ‘natural’ background levels that vary with climate change. Available evidence shows that modern humans can increase or decrease background levels of natural fire activity by clearing forests, promoting grazing, dispersing plants, altering ignition patterns and actively suppressing fires, thereby causing substantial ecosystem changes and loss of biodiversity. Some of these contemporary fire regimes cause substantial economic disruptions owing to the destruction of infrastructure, degradation of ecosystem services, loss of life, and smoke‐related health effects. These episodic disasters help frame negative public attitudes towards landscape fires, despite the need for burning to sustain some ecosystems. Greenhouse gas‐induced warming and changes in the hydrological cycle may increase the occurrence of large, severe fires, with potentially significant feedbacks to the Earth system. Improved understanding of human fire regimes demands: (1) better data on past and current human influences on fire regimes to enable global comparative analyses, (2) a greater understanding of different cultural traditions of landscape burning and their positive and negative social, economic and ecological effects, and (3) more realistic representations of anthropogenic fire in global vegetation and climate change models. We provide an historical framework to promote understanding of the development and diversification of fire regimes, covering the pre‐human period, human domestication of fire, and the subsequent transition from subsistence agriculture to industrial economies. All of these phases still occur on Earth, providing opportunities for comparative research.

Journal of Biogeography↗
USGS2015

Shift in Global Tantalum Mine Production, 2000–2014

Introduction Tantalum has a unique set of properties that make it useful in a number of diverse applications. The ability of the metal to store and release electrical energy makes it ideally suited for use in certain types of capacitors that are widely used in modern electronics. Approximately 60 percent of global tantalum consumption is in the electronics industry. The ductility and corrosion resistance of the metal lends itself to application in the chemical processing industry, and its high melting point and high strength retention at elevated temperatures make it an important component of super alloys used in aircraft engines. As a major industrialized nation, the United States is a leading consumer of tantalum and tantalum-containing products. Domestic deposits typically are of low grade, and no tantalum has been recovered from mining activities in the United States since 1959. Consequently, the United States is nearly completely reliant on imports to meet its domestic consumption of tantalum for economic and national security needs. The recovery of tantalum from mine production is economically viable in only a few countries. Although developed countries dominated tantalum mine production in the early 2000s, production today is dominated by countries in the Great Lakes Region of Africa. There is concern that the sales of minerals, including columbite-tantalite or “coltan,” a mineral from which tantalum is derived, have helped finance rebel groups accused of violating human rights as part of the continuing armed conflict in the Democratic Republic of the Congo (DRC) and neighboring countries. These accusations have prompted the passage of legislation in the United States to curb the procurement of these mineral commodities, referred to as “conflict minerals,” from the DRC. Specifically, section 1502 of the 2010 Dodd-Frank Wall Street Reform and Consumer Protection Act (Public Law 111–203, 124 Stat. 2213–2218) requires companies that source tantalum, tin, tungsten, and gold (3TG) to perform due diligence on their supply chains to determine if the materials they use originate from the DRC or adjoining countries (defined as sharing a border with the DRC). The DRC, Rwanda, and surrounding countries are not globally significant sources of tin, tungsten, or gold, accounting for only about 2 percent of the mined world supply for each of these elements. The region has, however, evolved to become the world’s largest producer of mined tantalum. A further complication of the production of tantalum stems from the opacity of the tantalum market. Unlike most base and precious metals, tantalum concentrates are not publicly traded through commodities exchanges but are bought and sold through networks of dealers and on contract between producers and consumers, some of whom may not provide accurate statistical data concerning the amounts, origins, and destination of the concentrates. Some price data can be found in trade journals or in other publications; however, there are no recognized official set exchange prices for either concentrate or tantalum metal. Because price is determined by negotiation between buyer and seller, published prices for concentrate are probably not representative of global prices paid for concentrate. The development of a mine-to-market supply-chain analysis is complicated and difficult because many of the industry participants that produce, trade, and consume tantalum do not publish statistical information, contracts are long term between miners and buyers, and much of the industry is vertically integrated. As a result of these and other considerations, tantalum is considered by many to be a “critical” commodity. This fact sheet identifies and addresses the major geographic shifts in the source of mine production of tantalum which have occurred over the past 15 years, some of the factors that drove this shift, and some of the related consequences. One of the activities of the U.S. Geological Survey National Minerals Information Center (USGS-NMIC) is to analyze global supply chains and characterize major components of mineral and material flows from ore extraction through processing to first tier products. These analyses support the core mission of the USGS-NMIC as the Federal entity responsible for the collection, analysis, and dissemination of objective, unbiased, factual information on minerals essential to the U.S. economy and national security.

Fact Sheet↗
USGS2007

Regional impact of water resource investments in an developing area

Regional development and industrialization patterns are investigated and related via regression analysis to water resource investments for the island of Puerto Rico. Although results of this study indicate such investments have little immediate or short‐term impact, significant relationships and variations in regional responses appear over longer time periods. This is shown by applying a variation of Zellner's method of performing seemingly unrelated regressions jointly. By this method, subsets of parameter coefficients of specific economic variables were restricted across regional equations while unrestricted coefficients were interpreted as explaining systematic regional variations in response to public investment. Regional differences, obtained by using this method, are frequently neglected when simply examining the overall development process. Among the more interesting results in terms of policy implications is the apparent significant relationship, over the period considered, between changes in the distribution of income and the pattern of water resource development.

Journal of the American Water Resources Associatio↗