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11.
Bryce A. Mihalevich Jeffery S. Horsburgh Anthony A. Melcher 《Environmental monitoring and assessment》2017,189(11):593
Stormwater runoff in urban areas can contribute high concentrations of dissolved organic matter (DOM) to receiving waters, potentially causing impairment to the aquatic ecosystem of urban streams and downstream water bodies. Compositional changes in DOM due to storm events in forested, agricultural, and urban landscapes have been well studied, but in situ sensors have not been widely applied to monitor stormwater contributions in urbanized areas, leaving the spatial and temporal characteristics of DOM within these systems poorly understood. We deployed fluorescent DOM (FDOM) sensors at upstream and downstream locations within a study reach to characterize the spatial and temporal changes in DOM quantity and sources within an urban water conveyance that receives stormwater runoff. Baseflow FDOM decreased over the summer season as seasonal flows upstream transported less DOM. FDOM fluctuated diurnally, the amplitude of which also declined as the summer season progressed. During storms, FDOM concentrations were rapidly elevated to values orders of magnitude greater than baseflow measurements, with greater concentrations at the downstream monitoring site, revealing high contributions from stormwater outfalls between the two locations. Observations from custom, in situ fluorometers resembled results obtained using laboratory methods for identifying DOM source material and indicated that DOM transitioned to a more microbially derived composition as the summer season progressed, while stormwater contributions contributed DOM from terrestrial sources. Deployment of a mobile sensing platform during varying flow conditions captured spatial changes in DOM concentration and composition and revealed contributions of DOM from outfalls during stormflows that would have otherwise been unobserved. 相似文献
12.
Contaminants in fish tissue from US lakes and reservoirs: a national probabilistic study 总被引:1,自引:0,他引:1
Leanne L. Stahl Blaine D. Snyder Anthony R. Olsen Jennifer L. Pitt 《Environmental monitoring and assessment》2009,150(1-4):3-19
An unequal probability design was used to develop national estimates for 268 persistent, bioaccumulative, and toxic chemicals in fish tissue from lakes and reservoirs of the conterminous United States (excluding the Laurentian Great Lakes and Great Salt Lake). Predator (fillet) and bottom-dweller (whole body) composites were collected from 500 lakes selected randomly from the target population of 147,343 lakes in the lower 48 states. Each of these composite types comprised nationally representative samples whose results were extrapolated to the sampled population of an estimated 76,559 lakes for predators and 46,190 lakes for bottom dwellers. Mercury and PCBs were detected in all fish samples. Dioxins and furans were detected in 81% and 99% of predator and bottom-dweller samples, respectively. Cumulative frequency distributions showed that mercury concentrations exceeded the EPA 300 ppb mercury fish tissue criterion at nearly half of the lakes in the sampled population. Total PCB concentrations exceeded a 12 ppb human health risk-based consumption limit at nearly 17% of lakes, and dioxins and furans exceeded a 0.15 ppt (toxic equivalent or TEQ) risk-based threshold at nearly 8% of lakes in the sampled population. In contrast, 43 target chemicals were not detected in any samples. No detections were reported for nine organophosphate pesticides, one PCB congener, 16 polycyclic aromatic hydrocarbons, or 17 other semivolatile organic chemicals. 相似文献
13.
14.
Quang A. Phung Allen L. Thompson Claire Baffaut Christine Costello E. John Sadler Bohumil M. Svoma Anthony Lupo Sagar Gautam 《Journal of the American Water Resources Association》2019,55(5):1196-1215
Anticipating changes in hydrologic variables is essential for making socioeconomic water resource decisions. This study aims to assess the potential impact of land use and climate change on the hydrologic processes of a primarily rain‐fed, agriculturally based watershed in Missouri. A detailed evaluation was performed using the Soil and Water Assessment Tool for the near future (2020–2039) and mid‐century (2040–2059). Land use scenarios were mapped using the Conversion of Land Use and its Effects model. Ensemble results, based on 19 climate models, indicated a temperature increase of about 1.0°C in near future and 2.0°C in mid‐century. Combined climate and land use change scenarios showed distinct annual and seasonal hydrologic variations. Annual precipitation was projected to increase from 6% to 7%, which resulted in 14% more spring days with soil water content equal to or exceeding field capacity in mid‐century. However, summer precipitation was projected to decrease, a critical factor for crop growth. Higher temperatures led to increased potential evapotranspiration during the growing season. Combined with changes in precipitation patterns, this resulted in an increased need for irrigation by 38 mm representing a 10% increase in total irrigation water use. Analysis from multiple land use scenarios indicated converting agriculture to forest land can potentially mitigate the effects of climate change on streamflow, thus ensuring future water availability. 相似文献
15.
Resolution and Analysis of Spatial Variations and Patterns in an Urban Lake with Rapid Profiling Instrumentation 下载免费PDF全文
Anthony R. Prestigiacomo Steven W. Effler David A. Matthews 《Journal of the American Water Resources Association》2015,51(1):200-213
Rapid response vertical profiling instrumentation was used to document spatial variability and patterns in a small urban lake, Onondaga Lake, associated with multiple drivers. Paired profiles of temperature, specific conductance (SC), turbidity (Tn), fluorometric chlorophyll a (Chlf), and nitrate nitrogen (NO3?) were collected at >30 fixed locations (a “gridding”) weekly, over the spring to fall interval of several years. These gridding data are analyzed (1) to characterize phytoplankton (Chlf) patchiness in the lake's upper waters, (2) to establish the representativeness of a single long‐term site for monitoring lake‐wide conditions, and (3) to resolve spatial patterns of multiple tracers imparted by buoyancy effects of inflows. Multiple buoyancy signatures were resolved, including overflows from less dense inflows, and interflows to metalimnetic depths and underflows to the bottom from the plunging of more dense inputs. Three different metrics had utility as tracers in depicting the buoyancy signatures as follows: (1) SC, for salinity‐enriched tributaries and the more dilute river that receives the lake's outflow, (2) Tn, for the tributaries during runoff events, and (3) NO3?, for the effluent of a domestic waste treatment facility and from the addition of NO3? solution to control methyl mercury. The plunging inflow phenomenon, which frequently prevailed, has important management implications. 相似文献
16.
Raymond Anthony 《Journal of Agricultural and Environmental Ethics》2012,25(2):123-144
Agricultural technologies are non-neutral and ethical challenges are posed by these technologies themselves. The technologies
we use or endorse are embedded with values and norms and reflect the shape of our moral character. They can literally make
us better or worse consumers and/or people. Looking back, when the world’s developed nations welcomed and steadily embraced
industrialization as the dominant paradigm for agriculture a half century or so ago, they inadvertently championed a philosophy
of technology that promotes an insular human-centricism, despite its laudable intent to ensure food security and advance human
flourishing. The dominant philosophy of technology has also seeded particular ethical consequences that plague the well-being
of human beings, the planet, and farmed animals. After revisiting some fundamental questions regarding the complex ways in
which technology as agent shapes our lives and choices and relegates food and farmed constituents into technological artifacts or commodities, I argue
that we should accord an environmental virtue ethic of care—understood as caretaking—a central place in developing a more
conscientious philosophy of technology that aims at sustainability, fairness, and humaneness in animal agriculture. While
technology shapes society, it also is socially shaped and an environmental virtue ethic of care (EVEC) as an alternative design
philosophy has the tools to help us take a much overdue inventory of ourselves and our relationships with the nonhuman world.
It can help us to expose the ways in which technology hinders critical reflection of its capacity to alter communities and
values, to come to terms with why we may be, in general, disengaged from critical ethical analysis of contemporary agriculture
and to consider the moral shape and trajectory and the sustainability of our food production systems going into the future.
I end by outlining particular virtues associated with the ethic of care discussed here and consider some likely implications
for consumers and industry technocrats as they relate to farming animals. 相似文献
17.
John R. Dymond Tim J. A. Davie Andrew D. Fenemor Jagath C. Ekanayake Ben R. Knight Anthony O. Cole Oscar Montes de Oca Munguia Will J. Allen Roger G. Young Les R. Basher Marc Dresser Chris J. Batstone 《Environmental management》2010,46(3):484-493
Can we develop land use policy that balances the conflicting views of stakeholders in a catchment while moving toward long term sustainability? Adaptive management provides a strategy for this whereby measures of catchment performance are compared against performance goals in order to progressively improve policy. However, the feedback loop of adaptive management is often slow and irreversible impacts may result before policy has been adapted. In contrast, integrated modelling of future land use policy provides rapid feedback and potentially improves the chance of avoiding unwanted collapse events. Replacing measures of catchment performance with modelled catchment performance has usually required the dynamic linking of many models, both biophysical and socio-economic—and this requires much effort in software development. As an alternative, we propose the use of variable environmental intensity (defined as the ratio of environmental impact over economic output) in a loose coupling of models to provide a sufficient level of integration while avoiding significant effort required for software development. This model construct was applied to the Motueka Catchment of New Zealand where several biophysical (riverine water quantity, sediment, E. coli faecal bacteria, trout numbers, nitrogen transport, marine productivity) models, a socio-economic (gross output, gross margin, job numbers) model, and an agent-based model were linked. An extreme set of land use scenarios (historic, present, and intensive) were applied to this modelling framework. Results suggest that the catchment is presently in a near optimal land use configuration that is unlikely to benefit from further intensification. This would quickly put stress on water quantity (at low flow) and water quality (E. coli). To date, this model evaluation is based on a theoretical test that explores the logical implications of intensification at an unlikely extreme in order to assess the implications of likely growth trajectories from present use. While this has largely been a desktop exercise, it would also be possible to use this framework to model and explore the biophysical and economic impacts of individual or collective catchment visions. We are currently investigating the use of the model in this type of application. 相似文献
18.
Jahn Kallis Leo Bodensteiner Anthony Gabriel 《Journal of the American Water Resources Association》2010,46(4):744-756
Kallis, Jahn, Leo Bodensteiner, and Anthony Gabriel, 2010. Hydrological Controls and Freshening in Meromictic Soap Lake, Washington, 1939-2002. Journal of the American Water Resources Association (JAWRA) 46(4): 744-756. DOI: 10.1111/j.1752-1688.2010.00446.x Abstract: The chemically stratified layer of naturally formed meromictic lakes exhibits unusual and often extreme physical and chemical conditions that have resulted in the evolution of uniquely adapted species. The Columbia Basin Irrigation Project appears to have had a marked effect on the hydrology of Soap Lake, a meromictic lake in the Grand Coulee of central Washington. The relation of hydrology to salinity was assessed by analyzing water budgets before and after the introduction of the irrigation project. Before irrigation, water gains were balanced by losses; after irrigation began groundwater gains approximately doubled. To manage lake levels and reduce groundwater influx, wells were installed to intercept groundwater. Although the hydrological cycle has been restored to pre-irrigation conditions, the meromictic character of the lake continues to change. Interception wells remove 10 to 16 Mm3 of groundwater annually, but influx continues based on change in the monimolimnion. From 1958 to 2003 the chemocline descended 1.1 m and the volume of the monimolimnion from 698,000 m3 to 114,000 m3. Annual loss of volume is occurring at a rate of 1.9% since 1958. Although groundwater interception wells are maintaining the volume of the entire lake, the recession of the chemocline indicates that conditions that have maintained meromixis at Soap Lake are currently not in equilibrium. 相似文献
19.
Bryant RB Buda AR Kleinman PJ Church CD Saporito LS Folmar GJ Bose S Allen AL 《Journal of environmental quality》2012,41(3):664-671
High levels of accumulated phosphorus (P) in soils of the Delmarva Peninsula are a major source of dissolved P entering drainage ditches that empty into the Chesapeake Bay. The objective of this study was to design, construct, and monitor a within-ditch filter to remove dissolved P, thereby protecting receiving waters against P losses from upstream areas. In April 2007, 110 Mg of flue gas desulfurization (FGD) gypsum, a low-cost coal combustion product, was used as the reactive ingredient in a ditch filter. The ditch filter was monitored from 2007 to 2010, during which time 29 storm-induced flow events were characterized. For storm-induced flow, the event mean concentration efficiency for total dissolved P (TDP) removal for water passing through the gypsum bed was 73 ± 27% confidence interval (α = 0.05). The removal efficiency for storm-induced flow by the summation of load method was 65 ± 27% confidence interval (α = 0.05). Although chemically effective, the maximum observed hydraulic conductivity of FGD gypsum was 4 L s(-1), but it decreased over time to <1 L s(-1). When bypass flow and base flow were taken into consideration, the ditch filter removed approximately 22% of the TDP load over the 3.6-yr monitoring period. Due to maintenance and clean-out requirements, we conclude that ditch filtration using FGD gypsum is not practical at a farm scale. However, we propose an alternate design consisting of FGD gypsum-filled trenches parallel to the ditch to intercept and treat groundwater before it enters the ditch. 相似文献
20.
Hydropower,adaptive management,and Biodiversity 总被引:2,自引:0,他引:2
Adaptive management is a policy framework within which an iterative process of decision making is followed based on the observed responses to and effectiveness of previous decisions. The use of adaptive management allows science-based research and monitoring of natural resource and ecological community responses, in conjunction with societal values and goals, to guide decisions concerning man's activities. The adaptive management process has been proposed for application to hydropower operations at Glen Canyon Dam on the Colorado River, a situation that requires complex balancing of natural resources requirements and competing human uses. This example is representative of the general increase in public interest in the operation of hydropower facilities and possible effects on downstream natural resources and of the growing conflicts between uses and users of river-based resources. This paper describes the adaptive management process, using the Glen Canyon Dam example, and discusses ways to make the process work effectively in managing downstream natural resources and biodiversity. 相似文献