• Issue

    Water Resources Research: Volume 57, Issue 1

    January 2021

Research Article

Free Access

Coupled Morphodynamics of River Bifurcations and Confluences

  • First Published: 08 December 2020
Key Points

  • The dominating branch of a channel confluence shows a higher water level, depending on the square of the Froude number

  • The confluence exerts a negative feedback on the upstream bifurcation, which promotes the stability of the system

  • The bifurcation-confluence system can be stable even when the bedload steering at the bifurcation is very weak

Climate

Free Access

Modeling the Transport of Aggregating Nanoparticles in Porous Media

  • First Published: 11 December 2020
Key Points

  • Transport of aggregating nanoparticles in porous media is different from that of conventional nonaggregating biocolloids

  • Aggregation was shown to affect nanoparticle attachment onto the solid matrix

  • Possible unrealistic results are generated when aggregation, size dependent dispersivity or surface charges are neglected

Open Access

Factors Determining the Natural Fresh-Salt Groundwater Distribution in Deltas

  • First Published: 14 December 2020
Key Points

  • Global sensitivity analysis of a three-dimensional, variable-density groundwater model with complex paleo-hydrological boundary conditions

  • The wide range of geometries, hydrogeological parameterizations, and boundary conditions is representative for many deltas worldwide

  • Results suggest that fresh-salt groundwater distributions are not in dynamic equilibrium in at least half of the real-world cases analyzed

Free Access

Two-Phase Fluid Flow Properties of Rough Fractures With Heterogeneous Wettability: Analysis With Lattice Boltzmann Simulations

  • First Published: 07 December 2020
Key Points

  • Heterogeneous wettability distributions promote residual saturation during multiphase flow in fractures

  • The evolution of unsteady permeability in fractures is partially controlled by the distribution of wettability

  • Steady-state relative permeability and saturation are strongly correlated to the standard deviation of the capillary pressure field

Open Access

Physical Instability of Individuals Exposed to Storm-Induced Coastal Flooding: Vulnerability of New Yorkers During Hurricane Sandy

  • First Published: 22 December 2020
Key Points

  • A physics-based model quantifying individuals' vulnerability to combined floodwater and wind hazard is developed

  • Winds substantially influence human vulnerability to coastal flooding

  • Human physical vulnerability in New York City to coastal flooding during Hurricane Sandy is revealed

Free Access

Probability and Consequence of Postfire Erosion for Treatability of Water in an Unfiltered Supply System

  • First Published: 07 December 2020
Key Points

  • Consequence of wildfire for an unfiltered water supply system is modeled based on erosion, stochastic rainfall, and reservoir hydrodynamics

  • There is a 10–30% chance that water is untreatable for >1 year due to high suspended sediment concentration after a high-severity wildfire

  • Assumptions about spatiotemporal rainfall patterns, reservoir hydrodynamics, and erosion are all important sources of error in risk

Free Access

A Quasi-Newton Reformulated Geostatistical Approach on Reduced Dimensions for Large-Dimensional Inverse Problems

  • First Published: 09 December 2020
Key Points

  • A quasi-Newton approach is developed in reformulated geostatistical approach framework for large-dimensional inverse modeling

  • Broyden's method is applied to update the Jacobian of forward models with respect to retained principal axes and drift coefficients

  • Compared with Newton method, the developed approach saves 60–70% of forward model runs for large-dimensional hydraulic tomography

Free Access

Inverse Estimation of Spatiotemporal Flux Boundary Conditions in Unsaturated Water Flow Modeling

  • First Published: 16 December 2020
Key Points

  • Spatiotemporal top flux is inversely estimated in unsaturated water flow modeling from soil moisture dynamics using Tikhonov regularization

  • When top fluxes vary with time only (special case), the inversion reduces to be well-posed and is explicitly solved without regularization

  • The method's performance is evaluated by synthetic data and its applicability in the special case is further verified in field examples

Free Access

Time-Varying Sensitivity Analysis Reveals Relationships Between Watershed Climate and Variations in Annual Parameter Importance in Regions With Strong Interannual Variability

  • First Published: 22 December 2020
Key Points

  • Annual time-varying sensitivity analysis revealed unique patterns of parameter importance across 21 proximal study watersheds

  • Low elevation parameter importance to Kling-Gupta Efficiency varied with precipitation, while shifts at high elevations varied with elevation

  • Parameter sensitivity to select hydrological signatures was generally static through time, despite annual variations in observed values

Free Access

Probabilistic Projections of Multidimensional Flood Risks at a Convection-Permitting Scale

  • First Published: 14 December 2020
Key Points

  • Probabilistic projections of multidimensional flood risks were developed at a convection-permitting scale

  • High-resolution climate projections with the 4-km horizontal grid spacing were developed using the convection-permitting Weather Research and Forecasting model

  • Bayesian vine copula approach was proposed to uncover potential interactions among flood variables and associated uncertainties

Free Access

A Self-Calibration Variance-Component Model for Spatial Downscaling of GRACE Observations Using Land Surface Model Outputs

  • First Published: 16 December 2020
Key Points

  • A self-calibration variance-component model for spatial downscaling of GRACE total water storage

  • Generation of high-resolution total water storage by combination of GRACE observations and land surface model outputs

  • Evaluation of groundwater storage monitoring with GRACE observations

Open Access

A Framework for Estimating Global-Scale River Discharge by Assimilating Satellite Altimetry

  • First Published: 07 December 2020
Key Points

  • A framework for assimilating satellite altimetry into a global river hydrodynamic model was developed to estimate river discharge globally

  • Virtual experiments for the future SWOT satellite suggest discharge in downstream reaches of continental rivers can be accurately estimated

  • Correct hydrodynamic parameterization will enhance the accuracy of river discharge estimates when SWOT observations become available

Free Access

Evaluating the Ubiquity of Thresholds in Rainfall-Runoff Response Across Contrasting Environments

  • First Published: 11 December 2020
Key Points

  • While water volume thresholds dominate the literature, rainfall intensity thresholds were observed even at sites with humid climates

  • Threshold behavior is sensitive to antecedent conditions over specific durations of time preceding a rainfall-runoff event

  • A newly proposed typology of threshold dynamics may be used toward standardized threshold descriptions and intersite comparisons

Free Access

Tracking lake surface elevations with proportional hypsometric relationships, Landsat imagery, and multiple DEMs

  • First Published: 18 December 2020
Key Points

  • Lowest hydroflattened surface models reduce low-level water surface elevation estimate uncertainty

  • Proportional hypsometry substantially increases the temporal resolution of the analysis while maintaining similar accuracy

Free Access

Representing Intercell Lateral Groundwater Flow and Aquifer Pumping in the Community Land Model

  • First Published: 04 December 2020
Key Points

  • A new prognostic groundwater model is implemented into the latest version of the Community Land Model (CLM5)

  • The new model accounts for lateral groundwater flow and conjunctive use of groundwater and surface water for irrigation

  • Significant improvements are achieved in simulating the spatiotemporal dynamics of water level over the heavily exploited US aquifers

Free Access

Hydrologic-Economic Trade-offs in Groundwater Allocation Policy Design

  • First Published: 11 December 2020
Key Points

  • We examine the trade-offs of alternative groundwater allocation policies on farm profitability and stream depletion

  • Multi-year allocations smooth income and reduce water-related production risk but cause higher stream depletion than single-year allocations

  • Trade-offs between single-year and multi-year allocations increase for longer allocation periods and wells closer to streams

Comment

Open Access

Comment on Dong and Ochsner (2018): “Soil Texture Often Exerts Stronger Influence Than Precipitation on Mesoscale Soil Moisture Patterns”

  • First Published: 14 December 2020
Key Points

  • Dong and Ochsner (2018) concluded that soil texture exerted a stronger influence on mesoscale soil moisture variability than precipitation

  • Dong and Ochsner (2018) made a mistake in their calculation of volumetric soil moisture

  • We found that correlations between soil moisture and soil texture and precipitation were significantly different in only 8 of 18 surveys

Research Article

Free Access

Role of Pore-Scale Disorder in Fluid Displacement: Experiments and Theoretical Model

  • First Published: 13 December 2020
Key Points

  • We propose a theoretical model to describe the transitions of displacement patterns as functions of disorder and capillary number

  • Effects of disorder on both capillary and viscous forces are considered in the model and the phase diagram agrees with experiments

  • Higher disorder destabilizes fronts and dissipates more energy, with the dissipation ratio increasing from 28.3% to 56.7%

Open Access

Assessing Streamflow Sensitivity to Precipitation Variability in Karst-Influenced Catchments With Unclosed Water Balances

  • First Published: 11 December 2020
Key Points

  • We integrate modeling approaches for karstic and non-karstic systems to account for intercatchment groundwater flow in mixed catchments

  • We show that our combined approach reduces on average water balance errors by 18% and RMSEs by 20% at six test catchments

  • We find that karst controls between 65% and 93% of the total streamflow sensitivity to precipitation in these studied catchments

Issue Information

Free Access

Issue Information

  • First Published: 12 January 2021

Research Article

Open Access

Satellites to Sprinklers: Assessing the Role of Climate and Land Cover Change on Patterns of Urban Outdoor Water Use

  • First Published: 01 December 2020
Key Points

  • The percent of water used outdoors in Denver increased from 2000 to 2018, indicating the need for improved outdoor demand management

  • Increasing temperatures are driving most significant increases in outdoor water use at the census block group scale in Denver

  • Impervious land cover is nonlinearly and inversely related to irrigation rates at the census block group level in Denver

Research Articles

Free Access

Impact of Sub-core-scale Heterogeneity on Meter-Scale Flow and Brine Displacement in Drainage by CO2

  • First Published: 09 November 2020
Key Points

  • A meter-scale rock model with sub-core-scale heterogeneity from coreflooding experiments is presented
  • Comparison between meter-scale flow solution and coreflooding experiment shows significant differences due to boundary effects
  • A relationship between the amount of trapped brine, permeability statistical parameters, and Bond number is found

Research Article

Free Access

A Mahalanobis Distance-Based Automatic Threshold Selection Method for Peaks Over Threshold Model

  • First Published: 04 December 2020
Key Points

  • Proposes a novel Mahalanobis distance-based automatic threshold selection (TS) method for modeling hydrological extremes using Peaks Over Threshold model

  • Potential of approach is shown through simulation experiments and application on rainfall and flood data by considering four other TS methods

  • Approach alleviates uncertainty and ambiguity in TS arising from several issues associated with the conventional TS methods considered

Technical Reports: Methods

Open Access

Spreadsheet Tools for Quantifying Seepage Flux Across the GW-SW Interface

  • First Published: 06 October 2020
Key Points

  • Open-access spreadsheet-based calculation tools are presented for estimating vertical seepage flux from sediment temperatures
  • Data from a study site is used to compare performance of various one-dimensional analytical models
  • The influence of monitoring network design and precipitation events on the usability of model output is demonstrated

Research Article

Free Access

Mobilization of Geochemical Elements to Surface Water in the Active Layer of Permafrost in the Russian Arctic

  • First Published: 09 December 2020
Key Points

  • Locate geochemical tracer to identify active layers during summer permafrost melt

  • Assessed mobility of releasing geochemical elements to surrounding water bodies

  • Identified permafrost active layer using geochemical elements' concentrations

Research Articles

Free Access

Comparing Flood Projection Approaches Across Hydro-Climatologically Diverse United States River Basins

  • First Published: 20 November 2020
Key Points

  • Long-term flood projection approaches are compared across 233 U.S. river basins using split-sample tests over the historic period
  • Precipitation informed is useful for regional change projections; hydrologic simulation is useful for direction of change in a single basin
  • General circulation model outputs as forcing introduces less additional bias for precipitation informed compared to hydrologic simulation

Free Access

A Simplified Model for the Phase Composition Curve of Saline Soils Considering the Second Phase Transition

  • First Published: 31 October 2020
Key Points

  • The correlation between the matrix effect and the freezing point depression is simplified
  • A new conceptual model for the phase composition curve of saline soils is proposed and validated
  • The phase composition characteristics of the pore solution of saline soils are analyzed

Research Article

Free Access

Global Surface Soil Moisture Drydown Patterns

  • First Published: 02 December 2020
Key Points

  • Quantification of global soil moisture drydown patterns at SM Active Passive (SMAP) footprint using a nonparametric method

  • Seasonally variable soil, vegetative, and atmospheric controls are observed in effective soil water retention parameters at SMAP footprint

  • Interseasonal variability in soil drydown parameters is governed by climate and landuse

Free Access

The Effect of Streamflow, Ambient Groundwater, and Sediment Anisotropy on Hyporheic Zone Characteristics in Alternate Bars

  • First Published: 08 December 2020
Key Points

  • Shallow and deep hyporheic zones (HZs) exist in alternate bars with different characteristics

  • The residence times distribution exhibit different level of bimodality

  • A predictive model is presented to estimate the variations in HZ characteristics with streamflow and ambient groundwater variations and sediment anisotropy

Open Access

Landscape-Scale Plant Water Content and Carbon Flux Behavior Following Moisture Pulses: From Dryland to Mesic Environments

  • First Published: 09 December 2020
Key Points

  • Ecosystem carbon fluxes and plant water content are sensitive to individual summer soil moisture pulses across dry to humid US biomes

  • Ecosystem carbon uptake and plant water content increase following moisture pulses more frequently in drier biomes

  • Unlike mesic vegetation, dryland vegetation responses vary depending on pulse magnitudes and antecedent moisture conditions

Free Access

Numerical and Experimental Validation of the Applicability of Active-DTS Experiments to Estimate Thermal Conductivity and Groundwater Flux in Porous Media

  • First Published: 08 December 2020
Key Points

  • Numerical and experimental validation of two methods to interpret active-Distributed Temperature Sensing (DTS) experiments in sediments

  • Determination of thermal conductivity and groundwater flux with low uncertainties

  • Definition of the applicability, range of measurements, and limits of active-DTS experiments

Free Access

Vine Copula Ensemble Downscaling for Precipitation Projection Over the Loess Plateau Based on High-Resolution Multi-RCM Outputs

  • First Published: 09 December 2020
Key Points

  • A vine copula ensemble downscaling method is proposed to jointly downscale the projected precipitation from multiple climate models

  • Postsimulation analyses of monthly precipitation projections over the Loess Plateau were conducted using seven regional climate models

  • This method can generate more ensemble series than conventional bias-correction methods, and thus more robust projections

Open Access

Disentangling the Impact of Catchment Heterogeneity on Nitrate Export Dynamics From Event to Long-Term Time Scales

  • First Published: 07 December 2020
Key Points

  • Analyzing the CQ relationship across time scales allows the disentanglement of the impact of catchment heterogeneity on nitrate export

  • Mountainous upstream subcatchments can dominate nitrate export during high flows and disproportionally contribute to nitrate loads

  • Agricultural downstream subcatchments can dominate nitrate export during low flow and pose a long-term threat to water quality

Open Access

An Interannual Probabilistic Assessment of Subsurface Water Storage Over Europe Using a Fully Coupled Terrestrial Model

  • First Published: 14 December 2020
Key Points

  • Terrestrial systems modeling gives an interannual probabilistic assessment of subsurface water storage

  • The hindsight water storage assessment of the drought years 2011/2012 and 2018/2019 provided useful results

  • The assessment can generate valuable information for pronounced dry and also wet anomalies of subsurface water storage

Free Access

A Mountain-Front Recharge Component Characterization Approach Combining Groundwater Age Distributions, Noble Gas Thermometry, and Fluid and Energy Transport Modeling

  • First Published: 11 December 2020
Key Points

  • MFR is a large recharge component in semiarid valley aquifers, but MFR components are difficult to quantify and sensitive to climate change

  • Age distributions, noble gas thermometry, and fluid/energy transport modeling combined as an approach to distinguish/quantify MFR components

  • Noble gas thermometry can help constrain age distributions, but assuming a constant Tr lapse rate may produce improbable recharge elevations because surface MFR can locally suppress water table temperatures in basin-fill aquifers