• Issue
    Volume 48, Issue 2
    February 2012

Commentaries

Free Access

Replies to comments on “A revisit of drawdown behavior during pumping in unconfined aquifers” by Neuman and Mishra

  • First Published: 03 February 2012
Key Points

  • Transition of water release mechanisms
  • Heterogeneous, variably saturated flow equation
  • Unconfined aquifers

Free Access

Comments on “A revisit of drawdown behavior during pumping in unconfined aquifers” by D. Mao, L. Wan, T.-C. J. Yeh, C.-H. Lee, K.-C. Hsu, J.-C. Wen, and W. Lu

  • First Published: 03 February 2012
Key Points

  • One must not draw general conclusions from one (numerical) experiment
  • Conclusions drawn by Mao et al on such basis are in part invalid
  • Mao et al. ignore and/or mischaracterize some relevant previous WRR papers

Regular Article

Free Access

Prediction and uncertainty of free convection phenomena in porous media

  • First Published: 29 February 2012
Key Points

  • The prediction issue of free convection was comprehensively reviewed
  • A quantitative evaluation was conducted to assist in elucidation
  • A paradigm change is significantly proposed to change our way of thinking

Free Access

An assessment of surface soil temperature products from numerical weather prediction models using ground-based measurements

  • First Published: 28 February 2012
Key Points

  • An assessment of NWP temperature products in preparation for SMAP satellite mission
  • GMAO and ECMWF provide temperature fields with an RMSE below 1.8 K at 6am

Free Access

Application of ground-penetrating radar to measure near-saturation soil water content in peat soils

  • First Published: 28 February 2012
Key Points

  • We show a new method for varying water content precisely near saturation
  • Calibrated models can improve geophysical estimates of water content in peat
  • GPR is used to estimate water content in near-saturation peat

Free Access

Relative permeability and trapping of CO2 and water in sandstone rocks at reservoir conditions

  • First Published: 28 February 2012
Key Points

  • CO2/water rel-perm and residual trapping are measured in 4 sandstones
  • Characteristic curves are consistent with water-wet rocks
  • Residual CO2 trapping is confirmed as significant

Free Access

Influence of soil structure and root water uptake strategy on unsaturated flow in heterogeneous media

  • First Published: 28 February 2012
Key Points

  • Standard root uptake models in heterogeneous media can lead to local wilting
  • Compensating RWU strategies attenuate, but do not eliminate local wilting
  • In the wet, influence of heterogeneity on head is similar with or without RWU

Free Access

Controlled CO2 injection into heterogeneous geologic formations for improved solubility and residual trapping

  • First Published: 24 February 2012
Key Points

  • Optimization method for improved sweep efficiency in geologic CO2 storage system
  • Enhancement and accelaration of residual and solubility trapping
  • Introduction of pseudo wells for optimization of injection rate allocation

Free Access

A modified surface energy balance algorithm for land (M-SEBAL) based on a trapezoidal framework

  • First Published: 23 February 2012
Key Points

  • SEBAL is of a rectangular framework of the relationship between fc and Trad
  • M-SEBAL substitutes a trapezoidal framework for the rectangular framework in SEBAL
  • M-SEBAL reduces subjectivity and ambiguity in ET estimation in SEBAL

Free Access

Using high-resolution distributed temperature sensing to quantify spatial and temporal variability in vertical hyporheic flux

  • First Published: 23 February 2012
Key Points

  • Shallow hyporheic flux hot spots organize by streambed morphologic unit
  • Flux may both increase and decrease through time within the same system
  • High resolution fiber-optic heat tracing is a valuable tool to the community

Free Access

Interannual variability of snowmelt in the Sierra Nevada and Rocky Mountains, United States: Examples from two alpine watersheds

  • First Published: 23 February 2012
Key Points

  • Snow is more spatially variable at the continental site than maritime site
  • Turbulent fluxes are more variable at the continental site than maritime site
  • Lag of streamflow behind snowmelt is associated with hydrogeology and melt rate

Free Access

Effect of spatial concentration fluctuations on effective kinetics in diffusion-reaction systems

  • First Published: 21 February 2012
Key Points

  • We studied the effect of fluctuations on non-linear reactions
  • We found and explained change in scaling behavior of the concentrations
  • Fluctuations decrease the rate of chemical reactions

Free Access

Geostatistical analysis of centimeter-scale hydraulic conductivity variations at the MADE site

  • First Published: 21 February 2012
Key Points

  • Direct-push tools provide information on hydraulic conductivity variations
  • Direct-push techniques are much more efficient than well-based techniques
  • Direct-push and well-based techniques give similar results at a well known site

Free Access

A topography-based scaling algorithm for soil hydraulic parameters at hillslope scales: Field testing

  • First Published: 18 February 2012
Key Points

  • Soil hydraulic parameters aggregated from 30 m to 1 km extents
  • Upscaling algorithm tested under different hydroclimates and soil complexities
  • Simulated and observed soil moisture matched across topography and landcover

Free Access

Pore-scale simulation of mixing-induced calcium carbonate precipitation and dissolution in a microfluidic pore network

  • First Published: 18 February 2012
Key Points

  • Pore-scale model of coupled fluid flow, reactive transport, and CaCO3 reaction
  • Mechanistical evaluation of precipitation and dissolution of CaCO3
  • Coupled effects of diffusion, hydrodynamics, and reaction

Free Access

A comparative study of multiple approaches to soil hydraulic parameter scaling applied at the hillslope scale

  • First Published: 18 February 2012
Key Points

  • Four different algorithms to upscale soil hydraulic parameters were compared
  • Equivalence of coarse scale parameters tested in a watershed
  • Better performance by inclusion of topography in hydraulic parameter scaling

Free Access

A phenomenological model for the flow resistance over submerged vegetation

  • First Published: 18 February 2012
Key Points

  • A novel approach for Manning's n in streams with submerged vegetation is derived
  • The model uses a description of momentum transfer via ejections and sweeps
  • The model is independent of plant spacing and usable for heterogeneous canopies

Free Access

On topographic controls of soil hydraulic parameter scaling at hillslope scales

  • First Published: 18 February 2012
Key Points

  • Influence of topographic variations on effective upscaled soil hydraulics
  • Effective upscaled parameters captured equivalent flows and states
  • Different topographic features inherit characteristics upscaling thresholds

Free Access

Improved methods for daily streamflow estimates at ungauged sites

  • First Published: 18 February 2012
Key Points

  • A regression based logarithmic interpolation method for FDC estimation
  • Spatial interpolation algorithm to obtain daily streamflow estimates
  • Methods developed in the paper show siginificant better performances

Free Access

Spectral induced polarization of shaly sands: Influence of the electrical double layer

  • First Published: 16 February 2012
Key Points

  • Induced polarization of shaly sands is controlled by the Stern layer
  • The quadrature conductivity depends on salinity and CEC
  • The model accounts for temperature and saturation

Free Access

Salt marsh ecohydrological zonation due to heterogeneous vegetation–groundwater–surface water interactions

  • First Published: 15 February 2012
Key Points

  • Variety of salt marsh root zone environments much greater than supposed
  • Heterogeneous plant and sediment hydraulics physically organize salt marshes
  • First realistic 3D model of coupled surface-groundwater salt marsh hydrology

Free Access

Stochastic simulation of nonstationary oscillation hydroclimatic processes using empirical mode decomposition

  • First Published: 15 February 2012
Key Points

  • Introduction of a stochastic simulation technique reproducing the NSO processes
  • Test of the proposed approach with synthetic datasets
  • Application of the proposed approach to a climate index and to streamflow data

Free Access

Modeling effects of floods on streambed hydraulic conductivity and groundwater-surface water interactions

  • First Published: 15 February 2012
Key Points

  • Preferential transport of fine bed sediments can increase hydraulic conductivity
  • Deposition of fine material can reduce bed conductivity and river-aquifer fluxes
  • A temporally varying bed can have long-lasting impacts on water composition

Free Access

Attribution of water resources evolution in the highly water-stressed Hai River Basin of China

  • First Published: 14 February 2012
Key Points

  • Attribution of observed water resource changes
  • Climate change and human activity
  • Couple climate model with hydrological model

Free Access

Contaminant discharge and uncertainty estimates from passive flux meter measurements

  • First Published: 14 February 2012
Key Points

  • Deliberate implementation of stochastic simulation for discharge estimation
  • Use effective number of independent data for simple approximations
  • Two pfm field examples for TCE and uranium plumes demonstrate results

Free Access

Do internal flow measurements improve the calibration of rainfall-runoff models?

  • First Published: 14 February 2012
Key Points

  • Multi-site calibration does not perform better than single-site calibration
  • Performance are equivalent at the catchment outlet and at interior points
  • Multi-site calibration does not allow to better identify distributed parameters

Free Access

Solute transport and retention in three-dimensional fracture networks

  • First Published: 11 February 2012
Key Points

  • Transport resistance is a key random variable for solute transport in rocks
  • Low values of transport resistance can be predicted reasonably well
  • Assumed hydraulic law will have a large impact on effective representation

Free Access

Solute transport in divergent radial flow with multistep pumping

  • First Published: 11 February 2012
Key Points

  • Transient pumping problems can be transformed into a steady-state flow problem
  • Cumulative injected flow domain is very efficient for transient pumping
  • Linear convolution can be applied on the cumulative injected flow domain

Free Access

Monitoring groundwater storage changes in the highly seasonal humid tropics: Validation of GRACE measurements in the Bengal Basin

  • First Published: 10 February 2012
Key Points

  • Validates satellite measurements of groundwater storage changes in the humid tropics
  • Evaluates the ability of various GRACE products to trace groundwater storage changes
  • Demonstrates the critical but often ignored contribution of surface water storage

Free Access

Diffusivity of rocks: Gas diffusion measurements and correlation to porosity and pore size distribution

  • First Published: 09 February 2012
Key Points

  • Gas diffusivity measured for consolidated rocks and construction materials
  • Archie's law describes diffusivity-porosity relation with different m values
  • Relations between diffusivity and pore-size distribution proposed

Free Access

Unified measurement system with suction control for measuring hysteresis in soil-gas transport parameters

  • First Published: 08 February 2012
Key Points

  • Development and verification of unified measurement system with suction control
  • Hysteresis of SWCC and gas transport parameters
  • Effects of trapped air content on gas transport parameters

Free Access

Sediment dynamics in a sand bed stream with riparian vegetation

  • First Published: 07 February 2012
Key Points

  • Convective fluxes of suspended sediment are dominant in shaping the streambed
  • Width variations and curvature affect transverse fluxes of sediment
  • Riparian vegetation interfere with convective fluxes and straightened the reach

Free Access

Predicting natural base-flow stream water chemistry in the western United States

  • First Published: 04 February 2012
Key Points

  • We develop data describing chemical and physical attributes of bedrock geology
  • Empirical models successfully predict stream chemistry from environmental data
  • Geochemistry > temperature > precipitation in predicting stream chemistry

Free Access

Flow and turbulence redistribution in a straight artificial pool

  • First Published: 02 February 2012
Key Points

  • Lateral flow convergence in pools is linked with flow deceleration
  • A simple 2D bedform generates 3D hydrodynamic effects
  • Alt. theories of pool formation are subcomponents of convective acceleration

Free Access

Tidal influence on seawater intrusion in unconfined coastal aquifers

  • First Published: 02 February 2012
Key Points

  • Tide-induced seawater circulation may reduce the extent of seawater intrusion
  • Freshwater discharge zone shifts seaward due to tide-induced seawater circulation
  • Glover solution is modified to account for the tidal effect on the saltwater wedge

Free Access

Bayesian assessment of the expected data impact on prediction confidence in optimal sampling design

  • First Published: 01 February 2012
Key Points

  • Non-linear optimization scheme that outmatches conventional linear methods
  • The flexibility allow to handle arbitrary goal-oriented formulations of OD
  • The method allows the combination with new development in handling uncertainty