Modeling the environmental susceptibility of landfill sites in California     

Victor Fernandez Nascimento  Nazli Yesiller  Keith C Clarke  Jean Pierre Henry Balbaud Ometto  Pedro R. Andrade  Anahi Chimini Sobral 《地理信息系统科学与遥感》2017,54(5):657-677

??The proper management of solid waste (SW) is a global environmental challenge. A major issue is the proper disposal of SW while balancing a wide range of criteria and working with different spatial data. In this study, we used geographic information system as a tool to perform multi-criteria decision analysis with an analytical hierarchy process to develop an environmental impact susceptibility model (EISM) for landfills. The model was applied to the state of California, USA and results are presented herein. In particular, the EISM considers factors such as geology, pedology, geomorphology, water resources, and climate as represented by 13 associated environmental indicators. The results of the EISM indicate that more than 75% of California’s territory is situated in areas with very low, low, and medium environmental impact susceptibility categories. However, in the remaining 25% of the state’s land, 61 landfills are located in the high and very high categories. These results are alarming because during the period from 2000 to 2015, these 61 landfills received approximately 308 million tons of SW, which corresponds to more than 57% of all SW disposed in California. The model results can be used toward mitigating the environmental impacts of these facilities.  相似文献   

Effects of Steady-State Assumption on Hydraulic Conductivity and Recharge Estimates in a Surficial Aquifer System     

Keith J. Halford 《Ground water》1999,37(1):70-79

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Clinopyroxene + liquid equilibria to 100 kbar and 2450 K   总被引：5，自引：1，他引：4  

Keith Putirka 《Contributions to Mineralogy and Petrology》1999,135(2-3):151-163

One of the most active issues in igneous petrology is the investigation of mantle melting, and subsequent differentiation. To evaluate alternative hypotheses for melting and differentiation it is essential to accurately predict clinopyroxene compositions in natural systems. Expressions have thus been derived that describe clinopyroxene-melt equilibria, and allow equilibrium clinopyroxene compositions to be calculated. These equations were constructed from least-squares regression analysis of experimental clinopyroxene-liquid pairs. The calibration database included clinopyroxenes synthesized from both natural and synthetic basalt compositions; experimental conditions ranged from 0 to 100 kbar and 1350 to 2450 K. Regression equations were based on thermodynamic functions. Empirical expressions were also derived, since such models yield more precise estimates of clinopyroxene compositions, and may be easily incorporated into existing liquid line-of-descent models. Such equations may be useful for calculation of high pressure liquid fractionation, or for constraining P-T conditions for basalts produced by partial melting of a pyroxene-bearing source. Models of mantle melting often rely on expressions involving simple element ratios. Partition coefficients (K _d ^cpx/liq ) for the minor elements, Na and Ti, were thus also calibrated as a function of P, T and composition. K _Ti ^cpx/liq , while sensitive to composition was relatively insensitive to P and T. In contrast, K _Na ^cpx/liq increases substantially with increasing P, and exceeded 1 in some experiments. Since oceanic basalts show variations in Na/Ti ratios, the potential exists for partial melting depths to be inferred from K _Na ^cpx/liq . Received: 28 May 1997 / Accepted: 20 November 1998  相似文献   

Recharge and Groundwater Flow Within an Intracratonic Basin,Midwestern United States          下载免费PDF全文

Samuel V. Panno  Zohreh Askari  Walton R. Kelly  Thomas M. Parris  Keith C. Hackley 《Ground water》2018,56(1):32-45

The conservative nature of chloride (Cl^?) in groundwater and the abundance of geochemical data from various sources (both published and unpublished) provided a means of developing, for the first time, a representation of the hydrogeology of the Illinois Basin on a basin‐wide scale. The creation of Cl^? isocons superimposed on plan view maps of selected formations and on cross sections across the Illinois Basin yielded a conceptual model on a basin‐wide scale of recharge into, groundwater flow within and through the Illinois Basin. The maps and cross sections reveal the infiltration and movement of freshwater into the basin and dilution of brines within various geologic strata occurring at basin margins and along geologic structures. Cross‐formational movement of brines is also seen in the northern part of the basin. The maps and cross sections also show barriers to groundwater movement created by aquitards resulting in areas of apparent isolation/stagnation of concentrated brines within the basin. The distribution of Cl^? within the Illinois Basin suggests that the current chemical composition of groundwater and distribution of brines within the basin is dependent on five parameters: (1) presence of bedrock exposures along basin margins; (2) permeability of geologic strata and their distribution relative to one another; (3) presence or absence of major geologic structures; (4) intersection of major waterways with geologic structures, basin margins, and permeable bedrock exposures; and (5) isolation of brines within the basin due to aquitards, inhomogeneous permeability, and, in the case of the deepest part of the basin, brine density effects.  相似文献   

A method for uncertainty constraint of catchment discharge and phosphorus load estimates          下载免费PDF全文

Michael J. Hollaway  Keith J. Beven  Clare Mc W. H. Benskin  Adrian L. Collins  Robert Evans  Peter D. Falloon  Kirsty J. Forber  Kevin M. Hiscock  Ron Kahana  Christopher J. A. Macleod  Mary C. Ockenden  Martha L. Villamizar  Catherine Wearing  Paul J. A. Withers  Jian G. Zhou  Nicholas J. Barber  Philip M. Haygarth 《水文研究》2018,32(17):2779-2787

River discharge and nutrient measurements are subject to aleatory and epistemic uncertainties. In this study, we present a novel method for estimating these uncertainties in colocated discharge and phosphorus (P) measurements. The “voting point”‐based method constrains the derived stage‐discharge rating curve both on the fit to available gaugings and to the catchment water balance. This helps reduce the uncertainty beyond the range of available gaugings and during out of bank situations. In the example presented here, for the top 5% of flows, uncertainties are shown to be 139% using a traditional power law fit, compared with 40% when using our updated “voting point” method. Furthermore, the method is extended to in situ and lab analysed nutrient concentration data pairings, with lower uncertainties (81%) shown for high concentrations (top 5%) than when a traditional regression is applied (102%). Overall, for both discharge and nutrient data, the method presented goes some way to accounting for epistemic uncertainties associated with nonstationary physical characteristics of the monitoring site.  相似文献   

Turbidity and suspended sediment dynamics in small catchments in the Nepal Middle Hills     

James Brasington  Keith Richards 《水文研究》2000,14(14):2559-2574

The Himalayan environment has, until recently, been perceived to be in a critical state of environmental decline, resulting from rapid population growth and associated land‐use change. Recent research, however, has emphasized the difficulty of developing an objective appraisal of the state of the environment in a region where empirical data are scarce and unstructured and where an understanding of the spatial and temporal dynamics of natural environmental processes remains highly uncertain. This paper presents results from an intensive three‐year project designed to help address the regional empirical deficit, establish detailed baseline environmental data and to gain an insight into storm period and seasonal suspended sediment dynamics. The instrumentation, calibration and analysis of high‐frequency infrared turbidimetric records from a number of small subcatchments in the Nepal Middle Hills are reported. Storm period and seasonal variation in turbidity and suspended sediment are examined and hysteresis patterns explored and explained. A variety of methods to estimate seasonal suspended sediment yield in a mixed land‐use catchment are examined, and found to vary by up to a factor of five. Despite the inherent uncertainty, all estimates of catchment sediment yield are found to be high with respect to erosion plot studies from the local area, and this suggests the importance of riparian and channel erosion as major sediment sources, a finding consistent with other regional studies. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Late Holocene vegetational history,human impact and pollen representativity variations in northern Cumbria,England     

Lisa Dumayne-Peaty  Keith Barber 《第四纪科学杂志》1998,13(2):147-164

The comparison of pollen diagrams and their inferred vegetational histories are an important component of palaeoecological research. Radiocarbon-dated pollen profiles from three cores taken from two adjacent mires located in northern Cumbria, Bolton Fell Moss and Walton Moss, have been used to reconstruct the Late Holocene vegetation history between the Bronze Age and the present day. The profiles have been interpreted in the light of available archaeological and historical records and, although the pollen records are broadly similar, there are some notable differences between them, particularly during Iron Age and medieval times. Dissimilarities between the diagrams are explored numerically, and the statistical and palynological results are discussed in relation to pollen representativity. The results suggest that it may be advantageous to construct more than one pollen diagram from a mire, or even adjacent mires, as extra-local pollen may be a more important part of the pollen rain than previously envisaged. © 1998 John Wiley & Sons, Ltd.  相似文献   

Replicability and variability of the recent macrofossil and proxy-climate record from raised bogs: field stratigraphy and macrofossil data from Bolton Fell Moss and Walton Moss,Cumbria, England     

Keith Barber  Lisa Dumayne-Peaty  Paul Hughes  Dmitri Mauquoy  Rob Scaife 《第四纪科学杂志》1998,13(6):515-528

Replication of results is a basic tenet of science, but in palaeoecology this is very time-consuming and the ‘signal’ is subject to ‘noise’. The derivation of proxy-climate signals from ombrotrophic peat was carried out originally using samples from open peat faces where the stratigraphic relationships could be easily observed. Now that such sections are rare and often degraded there is a need to demonstrate that data can be replicated from core profiles. Ten short cores taken from two adjacent bogs have been analysed for macrofossils and show a coherent series of changes, which are also similar to previous profiles from the same sites. It is concluded that variation between profiles is slight and less than observations of present vegetation mosaics might suggest. Recommendations for a standard approach to fieldwork on raised bogs that emphasises the utility of subfossil pool layers are proposed and the need for a secure chronology is stressed. © 1998 John Wiley & Sons, Ltd.  相似文献   

Book Review: Geomorphic Hazards edited by Olav Slaymaker,John Wiley & Sons Ltd,Chichester, 1996. No. of pages: viii+204. Price: £45.00. ISBN 0471962139.     

Keith Smith 《地球表面变化过程与地形》1997,22(9):899-900

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Book Review: Geomorphology Sans Frontieères edited by S. Brian McCann and Derek C. Ford,Wiley, New York, 1996. No. of pages: xiii+245. Price: $50.00 (hb). ISBN 0-471-96600-2     

Keith Clayton 《地球表面变化过程与地形》1997,22(11):1085-1085

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