Aquifer-yield continuum as a guide and typology for science-based groundwater management     

Suzanne A. Pierce  John M. Sharp Jr.  Joseph H. A. Guillaume  Robert E. Mace  David J. Eaton 《Hydrogeology Journal》2013,21(2):331-340

Groundwater availability is at the core of hydrogeology as a discipline and, simultaneously, the concept is the source of ambiguity for management and policy. Aquifer yield has undergone multiple definitions resulting in a range of scientific methods to calculate and model availability reflecting the complexity of combined scientific, management, policy, and stakeholder processes. The concept of an aquifer-yield continuum provides an approach to classify groundwater yields along a spectrum, from non-use through permissive sustained, sustainable, maximum sustained, safe, permissive mining to maximum mining yields, that builds on existing literature. Additionally, the aquifer-yield continuum provides a systems view of groundwater availability to integrate physical and social aspects in assessing management options across aquifer settings. Operational yield describes the candidate solutions for operational or technical implementation of policy, often relating to a consensus yield that incorporates human dimensions through participatory or adaptive governance processes. The concepts of operational and consensus yield address both the social and the technical nature of science-based groundwater management and governance.  相似文献   

Visible and near-infrared lightcurves of eight asteroids     

R.S. McCheyne  N. Eaton  A.J. Meadows 《Icarus》1985,61(3):443-460

B lightcurves are presented for seven asteroids (4, 20, 29, 31, 39, 115, and 349) together with visual and infrared color curves (BV, BK, VJ, and JK). A V broadband lightcurve for 40 Harmonia is also included. Color variations are observed for three asteroids (4, 31, and 115). The variation in the colors of 4 Vesta is discussed in terms of differences in surface composition. Pole positions and shapes are estimated for 20 Massalia, 29 Amphitrite, 31 Euphrosyne, and 39 Laetitia. Various UBVRIJHK colors are listed for these asteroids as well as for 5, 19, 44, 52, 83, 145, 386, and 471.  相似文献   

Spawning-stock biomass of scad (Trachurus trachurus L.) to the west of the British Isles, as indicated by egg surveys     

Eaton  D. R. 《ICES Journal of Marine Science》1989,45(3):231-247

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Effects of chromated copper arsenate (CCA) wood preservative on early fouling community formation.     

C J Brown  R A Eaton  C H Thorp 《Marine pollution bulletin》2001,42(11):1103-1113

The effects of the anti-marine-borer timber preservative CCA (a pressure impregnated solution of copper, chromium and arsenic compounds) on early fouling community formation were investigated during a number of field trials. The formation of a biofilm on the surface of CCA-treated and untreated timber panels of Scots pine was examined by scanning electron microscopy following submersion in Langstone Harbour, Portsmouth, UK for periods of 2, 7, 14 and 28 days. Results indicated a slightly faster rate of biofilm formation after 2 and 7 days of exposure on untreated timber compared to CCA-treated timber, although no differences were visible between panels after 14 and 28 days exposure, or between panels treated to different CCA loadings after all exposure periods. Settlement of the serpulid Ficopomatus enigmaticus and two species of barnacles (Elminius modestus and Balanus crenatus) onto the surface of untreated and CCA-treated panels of Scots pine was examined following 4 weeks exposure in a brackish water millpond at Emsworth, West Sussex. Numbers of individuals were higher on CCA-treated panels than on untreated panels, and in the case of F. enigmaticus abundance of individuals increased with increasing preservative loadings. Early colonization by macroalgal species on the surface of CCA-treated and untreated panels of Scots pine was examined following submersion of panels in Langstone Harbour for a period of 4 weeks. Percentage cover of most species of algae was similar on the surface of CCA-treated and untreated panels, with the exception of Hincksia granulosa and Ceramium nodulosum which had significantly higher percentage cover on untreated panels. Possible explanations for the recruitment patterns are discussed.  相似文献   

Effects of large floods on sediment transport and reach morphology in the cobble-bed Sainte Marguerite River     

B. C. Eaton  M. F. Lapointe   《Geomorphology》2001,40(3-4)

Sediment transport rates were estimated for two flood events on the cobble-bed Sainte Marguerite River in the Saguenay region, Canada. Morphologic methods were used to derive one set of estimates, and a combination of the Meyer-Peter and Muller equation with a dimensionless sediment transport ratio (after Dietrich et al. [Nature 340 (1989) 215]) was used to derive another set of estimates. Both sets of estimates give consistent results for the first event (which had a decade-scale return period), and for the second event (which was the largest flood on record and had a century-scale return period). The transport occurring during the second event was an order of magnitude greater than that occurring during the first event: despite this disparity in the transport intensity of the two events, the channel morphology remained qualitatively similar. The observed degree of channel stability is attributed to a change of channel pattern and the initiation of bed degradation following channel rectification in the 1960s.  相似文献   

Ultraviolet photometry from the orbiting astronomical observatory XXII. Ultraviolet light variation ofβ Lyrae     

Yoji Kondo  George E. McCluskey  Joel A. Eaton 《Astrophysics and Space Science》1976,41(1):121-137

Six-color ultraviolet light curves of the complex eclipsing binary system Lyr were obtained with the OAO-2 Wisconsin Experiment Package. The filters had a typical width at half maximum of 150 to 200 Å and centered at 1430, 1550, 1910, 2460, 2980 and 3320 Å. The most striking characteristics of the ultraviolet light curves are that the secondary minimum deepens at shorter wavelengths. This indicates that we arenot observing the eclipse effect of two stars having roughly a Planckian distribution of energy. In combination with the high resolution far ultraviolet spectra of Lyr recently obtained withCopernicus (OAO-3) Princeton Telescope Spectrometer, it is concluded that the far ultraviolet light curves are dominated by emission from the high temperature gas surrounding the binary system. The ultraviolet observations with OAO-2 andCopernicus are consistent with a model in which the enigmatic secondary component involves a gravitationally collapsed object, i.e., a black hole; however, alternative models are also admissible.  相似文献   

A conceptual model for meander initiation in bedload‐dominated streams     

Brett C. Eaton  Michael Church  Tim R. H. Davies 《地球表面变化过程与地形》2006,31(7):875-891

A simple analytic model is presented relating local sediment transport capacity to variance in the transverse shear stress distribution in a stream channel. The model is used to develop a physically based conceptual model for the initiation of meandering in straight, bedload‐dominated streams as a result of a feedback mechanism. The feedback maximizes the cross‐sectional shear stress variance and – in order to achieve stability – ultimately minimizes the energy slope at repeated locations along the channel, subject to steady‐state mass flux and the stability of the channel boundary. These locations develop into pools in a fully developed meandering channel; they represent attractor states wherein sediment continuity is satisfied using the least possible energy expenditure per unit length of channel. However, since the cross‐sectional geometry of a pool (and the adjacent bar) is asymmetric, these attractor states are only conditionally stable, requiring strong, curvature‐induced secondary circulation to maintain their asymmetry. Between two successive pools, a stream occupies a metastable, higher energy state (corresponding to a riffle) that requires greater energy expenditure per unit length of channel to transport the same volume of sediment. The model we present links processes at the scale of a channel width to adjustments of the channel sinuosity and slope at the scale of a channel reach. We argue that the reach‐scale extremal hypotheses employed by rational regime models are mathematical formalisms that permit a one‐dimensional theory to describe the three‐dimensional dynamics producing stream morphology. Our model is consistent with the results from stream table experiments, with respect to both the rate of development of meandering and the characteristics of the equilibrium channel morphology. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Rational regime model of alluvial channel morphology and response     

Brett C. Eaton  Michael Church  Robert G. Millar 《地球表面变化过程与地形》2004,29(4):511-529

A theoretical model is developed for predicting equilibrium alluvial channel form. The concept of greatest relative stability, achieved by maximizing resistance to ?ow in the ?uvial system, is presented as the basis for an optimization condition for alluvial systems. Discharge, sediment supply (quantity and calibre) and valley gradient are accepted as independent governing variates. The model is used to de?ne a dimensionless alluvial state space characterized by aspect ratio (W/d), relative roughness (D/d), and dimensionless shear stress (τ*) or, equivalently, channel slope (S). Each alluvial state exhibits unique values of Froude number and sediment concentration. The range of alluvial states for constant values of relative bank strength (parameterized by an apparent friction angle, ?′) forms a single plane in the state space (W/d, D/d, τ* or S). The scaling relations produced by the model are consistent with laboratory channels exhibiting a range of bank strengths, and with the behaviour of natural channels. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Comparisons of VHF radar,optical, and temperature fluctuation measurements ofC n 2 ,r 0 andθ 0     

Eaton  F. D.  Peterson  W. A.  Hines  J. R.  Peterman  K. R.  Good  R. E.  Beland  R. R.  Brown  J. H. 《Theoretical and Applied Climatology》1988,39(1):17-29

Theoretical and Applied Climatology - Comparisons are made of profiles of the refractive index structure parameter (C 2 ) and two derived quantities, transverse coherence length (r 0) and...  相似文献   

Mutagens in aquatic environments: The potential of a variety of priority contaminants     

Jerry Payne  A.D. Rahimtula  P. Eaton 《Marine environmental research》1984,14(1-4)

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