Many studies have examined how runoff (Q) responds to long‐term changes in precipitation (P) and temperature (T), but the effects of potential evapotranspiration (PET) have received less attention. We examine observational data sets for P, T, and Q; along with PET estimated from observations, to determine the extent to which derived P and PET runoff elasticities (𝜀𝑃 and 𝜀𝑃𝐸𝑇, the fractional changes

Variable‐density flow and mass transport are important processes for a variety of groundwater problems. This study numerically investigated 2‐D vertical unconfined aquifers with horizontal groundwater flow and vertical injection of dense solute from the top. In total, 189 numerical simulation cases were performed with various scenarios of boundary conditions and aquifer properties. Based on the simulation

Over half of the global population and the majority of the cities in coastal zones are at risk of coastal flooding. Changes in the occurrence of individual extremes and the interactions between hydrological and coastal variables can exacerbate flood risks. While extensive research has been conducted to understand and predict different types of flood hazards in isolation, spatial and temporal trends

Fluid injection in porous rock occurs in a variety of hydrogeological operations including wastewater disposal, CO2 sequestration, enhanced oil recovery, and geothermal energy extraction. Influx of fluid into the host rock is usually accompanied by induced permeability enhancement due to increased pore fluid pressure and consequent dilation of the pore volume. The effect would, in turn, enhance the

The interaction of sediment supply and hydrographs can affect, on a mesoscale, geomorphic features like pools and riffles, which are fundamental units of many gravel bed rivers. In the past decades, different hypotheses have been developed to characterize the hydrodynamics of pool‐riffle sequences; however, most of the previous studies considered equilibrium or near‐equilibrium sediment transport conditions

High‐resolution characterization of hydraulic properties and dense nonaqueous phase liquid (DNAPL) contaminant source is crucial to develop efficient remediation strategies. However, DNAPL characterization suffers from a limited number of borehole data in the field, resulting in a low‐resolution estimation. Moreover, high‐resolution DNAPL characterization requires a large number of unknowns to be estimated

Eutrophication of rivers and receiving waters has become a major environmental issue worldwide, which may further intensify due to projected climate changes and expansion of urbanization or agricultural development to meet the needs of increased human population. However, our understanding of climatic and land use change impacts on riverine nutrient retention and export to receiving waters is limited

The atmospheric freezing level (Z FL) determines the rain‐snow transition zone at the surface, how much rainfall is available for runoff, and the flood risk during a precipitation event. An accurate Z FL forecast is thus critical for reservoir operation, especially in mountain watersheds with narrow elevation bands like the Feather and North Fork Yuba in California, where a 500‐m elevation gain can

In spite of the importance of stream network dynamics for hydrology, ecology, and biogeochemistry, there is limited availability of analytical tools suitable for characterizing the temporal variability of the active fraction of river networks. To fill this gap, we introduce the concept of Stream Length Duration Curve (SLDC), the inverse of the exceedance probability of the total length of active streams

Conceptual uncertainty is considered one of the major sources of uncertainty in groundwater flow modeling. Hypothesis testing is essential to increase system understanding by analyzing and refuting alternative conceptual models. We present a systematic approach to conceptual model testing aimed at finding an ensemble of conceptual understandings consistent with prior knowledge and observational data

The significance of fracture roughness for hydraulic characterization of sparsely fractured (crystalline) rock using flow logs under steady‐state pumping conditions is investigated by numerical simulations in three‐dimensional fracture networks. A new solver for simulating flow in three‐dimensional discrete fracture networks is implemented using a hybrid finite volume and finite element method. The

Flexible vegetation plays key roles in the natural channel and riparian ecology. This paper investigates the drag coefficient C df of an emergent flexible vegetation array in a steady nonuniform flow. Laboratory flume tests of five vegetation densities exposed to a constant flow rate were conducted, and the variation in the water surface was accurately measured. The Saint‐Venant equation (SVE) was

The prediction of coupled non‐isothermal multiphase flow in porous media has been the subject of many theoretical and experimental studies in the past half a century. In particular, the evaporation phenomenon from the shallow subsurface has been extensively studied based on the notion of equilibrium phase change between liquid water and water vapor (i.e. instantaneous phase change). One of the frequent

Abstract

Aquatic models used for both freshwater and marine systems frequently need to account for submerged aquatic vegetation (SAV) due to its influence on flow and water quality. Despite its importance, parameterizations are generally adopted that simplify feedbacks from SAV, such as canopy properties (e.g., considering the deflected vegetation height) and the bulk friction coefficient. This study reports

Choosing (an) adequate model structure(s) for a given purpose, catchment, and data situation is a critical task in the modelling chain. However, despite model intercomparison studies, hypothesis testing approaches with modular modelling frameworks, and continuous efforts in model development and improvement, there are still no clear guidelines for identifying a preferred model structure. By introducing

In‐stream large wood (LW) is a prominent feature of forested aquatic ecosystems worldwide, yet many questions remain regarding the response of LW patterns to riparian timber harvesting. This paper proposes a conceptual model of wood storage response to harvesting and combines a unique 45 year record of LW with output from a wood budget model to examine changes in LW characteristics and long‐term impacts

The Surface Water Ocean Topography (SWOT) mission will launch in early 2022 to provide the first global inventory of terrestrial surface water. Although SWOT is primarily a research mission with key science objectives in both the oceanography and hydrology domains, SWOT data are expected to have application potential to address many societal needs. To identify SWOT applications, prepare for the use

Hydrologic models are used to simulate natural phenomena while making different assumptions about the levels of complexity with which natural processes should be represented. Global Sensitivity Analysis is regularly applied to understand how the inputs (including forcing, parameters, and initial states) of these models control their outputs. A less widely explored strategy to support such diagnostic

Geostatistical inversion with quantified uncertainty for non‐linear problems requires techniques for providing conditional realizations of the random field of interest. Many first‐order second‐moment methods are being developed in this field, yet almost impossible to critically test them against high‐accuracy reference solutions in high‐dimensional and nonlinear problems. Our goal is to provide a high‐accuracy

Soil erosion, poor water quality, and degraded ecosystems impose major cost burdens and challenges for stormwater managers. We present a stochastic hydro‐financial watershed modeling framework for designing an Environmental Impact Bond (EIB) ‐ a new form of financing for comprehensive, watershed scale interventions. EIB's provide capital for interventions that is repaid over time with interest by stakeholders

We investigate the influence of near‐surface wind conditions on sub‐surface gas transport and on soil‐atmosphere gas exchange for gases of different density. Results of a sand tank experiment are supported by a numerical investigation with a fully coupled porous medium‐free flow model, which accounts for wind turbulence. The experiment consists of a two‐dimensional bench‐scale soil tank containing

Solutes in rivers often come from multiple sources, notably precipitation (above) and generation from the subsurface (below). The question of which source is more influential in shaping the dynamics of solute concentration cannot be easily addressed due to the general lack of input data. An analysis of solute concentrations and their dependence on discharge across 585 catchments in 9 countries leads

Understanding the impacts of climate change and human activities on hydrological processes, especially the baseflow, is vital for sustainable water resource management. We analyzed the global changes in baseflow and BFI for 2374 global streamflow stations from 1970 to 2016 to examine their associations with precipitation, temperature, terrestrial water storage (TWS), normalized difference vegetation

Human activities have increased nitrate export from rivers, degrading coastal water quality. At deltaic river mouths, the flow of water through wetlands increases nitrate removal, and the spatial organization of removal rates influences coastal water quality. To understand the spatial distribution of nitrate removal in a river‐dominated delta, we deployed 23 benthic chambers across ecogeomorphic zones

It is widely recognized that waves inhibit river mouth progradation and reduce the avulsion timescale of deltaic channels. Nevertheless, those effects may not apply to downdrift‐deflected channels. In this study, we developed a coupled model to explore the effects of wave climate asymmetry and alongshore sediment bypassing on shoreline‐channel morphodynamics. The shoreline position and channel trajectory

The declining mountain snowpack is expected to melt earlier and more slowly with climate warming. Previous work indicates that lower snowmelt rates are associated with decreased runoff. However, earlier snowmelt could increase runoff via lower vegetation water use in early spring. The relative importance of these factors with regard to runoff is linked to site‐specific conditions such as plant available

Pore scale mineral dissolution reactions are of fundamental importance for sustaining life and determining the fate of chemicals in Earth’s near‐surface environments. However, experimental investigations are largely limited to macroscopic approaches due to difficulties in controlling and observing geochemical processes at the pore scale. Here, we present an experimental method using both femtosecond

We describe a novel framework for estimating subsurface properties, such as rock permeability and porosity, from time‐lapse observed seismic data by coupling full‐waveform inversion (FWI), subsurface flow processes, and rock physics models. For the inverse modeling, we handle the back propagation of gradients by an intrusive automatic differentiation strategy that offers three levels of user control:

Projection of extreme rainfall under climate change remains an area of considerable uncertainty. In the absence of geographically consistent simulations of extreme rainfall for the future, alternatives relying on physical relationships between a warmer atmosphere and its moisture carrying capacity are projected, scaling with a known atmospheric covariate. The most common atmospheric covariate adopted

For operational water management in lowlands and polders (for instance, in the Netherlands), lowland hydrological models are used for flow prediction, often as an input for a real‐time control system to steer water with pumps and weirs to keep water levels within acceptable bounds. Therefore, proper initialization of these models is essential. The ensemble Kalman filter (EnKF) has been widely used

Global flood models integrate flood maps of constant probability in space, ignoring the correlation between sites and thus potentially misestimating the risk posed by extreme events. Stochastic flood models alleviate this issue through the simulation of flood events with a realistic spatial structure, yet their proliferation at large scales has historically been inhibited by data quality and computer

Information about end‐of‐winter spatial distribution of snow depth is important for seasonal forecasts of spring/summer streamflow in high‐mountain regions. Nevertheless, such information typically relies upon extrapolation from a sparse network of observations at low elevations. Here, we test the potential of high‐resolution snow depth data derived from optical stereophotogrammetry of Pléiades satellites

Radar rainfall nowcasting, the process of statistically extrapolating the most recent rainfall observation, is increasingly used for very short range rainfall forecasting (less than 6 hr ahead). We performed a large‐sample analysis of 1,533 events, systematically selected for 4 event durations and 12 lowland catchments (6.5–957 km2), to determine the predictive skill of nowcasting. Four algorithms

A data set containing hydrometeorological and hydroclimatological data for 3,540 watersheds in North America is described. The data set contains four main parts: (a) observed hydrometeorological data including daily streamflow observations, precipitation, minimum temperature, and maximum temperature; (b) 20 bias‐corrected climate model projections for two Representative Concentration Pathway (RCP)

Hyporheic exchange is a crucial control of the type and rates of streambed biogeochemical processes, including metabolism, respiration, nutrient turnover, and the transformation of pollutants. Previous work has shown that increasing discharge during an individual peak flow event strengthens biogeochemical turnover by enhancing the exchange of water and dissolved solutes. However, due to the nonsteady

The multifaceted interface of plant roots, microbes, water, and soil can be considered a critical zone within the Critical Zone as it is host to many important dynamically linked processes, including the promotion of nutrient cycling through absorption and rhizodeposition, interaction and feedbacks with microorganisms and fungi, root‐facilitated hydraulic redistribution, and soil carbon dynamics. Such

When using single‐well push‐pull (SWPP) tests to characterize in situ aquifer related to reactive transport, approximate analytical solutions were preferred to determine the aquifer dispersivity and other parameters, due to its computational efficiency. Simplified models were proposed in this study to estimate the retardation factor for a SWPP test with a reactive tracer, where the dispersivity had

Analysis of flood and streamflow timing has recently gained prominence as a tool for attribution of climatic changes to flooding. Such studies generally apply circular statistics to the day of maximum flow in a calendar year and use nonparametric linear trend tests to investigate changes in flooding on a local or regional scale. Here we investigate both the center timing of streamflow and the day of

Groundwater plays a critical role in sustaining agriculture in California's Central Valley (CV). However, groundwater storage in the CV has been declining by around 3 km3/year over the last several decades, with much larger declines during the 2007–2009 and 2012–2015 droughts. Managed Aquifer Recharge (MAR) can potentially mitigate existing overdraft by recharging excess streamflows (during flood periods)

Determining variations in groundwater replenishment over a variety of time scales remains a challenge in the management and protection of groundwater resources. Specifically, capacity to use hydraulic data collected in small windows of time to infer long‐term changes can be limited by system responses. Groundwater ages offer an alternative approach as they represent the time since recharge occurred

Heterogeneity and a paucity of measurements of key material properties undermine the veracity of quantitative predictions of subsurface flow and transport. For such model forecasts to be useful as a management tool, they must be accompanied by computationally expensive uncertainty quantification, which yields confidence intervals, probability of exceedance, etc. We design and implement novel Multilevel

Understanding the mechanisms of liquid movement through fracture intersections is important for prediction of fluid flow and solute transport in unsaturated fractured media. Here we present a quasi‐static model to predict the dynamic splitting behavior of liquid slugs at a T‐junction, as a simplified representation of a fracture intersection and consisting of a main channel and a branch channel. The

A 5.25 m sediment core SRM‐1 and 45 surface samples from mangrove forests at the Shark River Estuary in the Everglades National Park, Florida, was examined by using X‐ray fluorescence and carbon isotopic analyses to study the history of intense hurricane landfall during the Late‐Holocene. Significance testing of the surface samples in relation to storm deposits from Hurricane Wilma suggests that elemental

No abstract is available for this article.

This study suggests a stochastic Bayesian approach for calibrating and validating morphodynamic sediment transport models and for quantifying parametric uncertainties in order to alleviate limitations of conventional (manual, deterministic) calibration procedures. The applicability of our method is shown for a large‐scale (11.0 km) and time‐demanding (9.14 hr for the period 2002–2013) 2‐D morphodynamic

Mountains are a source of water for downstream areas; thus, it is important to understand the storage and discharge characteristics of steep mountain catchments. Nested catchment studies have indicated that the relation between catchment area and specific discharge during baseflow can represent mesoscale storage and discharge characteristics, but this is poorly understood. We found that baseflow‐specific

The optimization of water networks supports the decision‐making process by identifying the optimal trade‐off between costs and performance (e.g., resilience, leakage, etc.). A major challenge in the domain of water distribution systems (WDSs) is the network (re)design. While the complex nature of WDS has already been explored with complex network analysis (CNA), literature is still lacking a CNA of

Knowledge of coastal groundwater flow is critical for managing coastal groundwater resources and quantifying submarine groundwater discharge (SGD), but this flow occurs over multiple scales that can be difficult to study in an integrated way. We designed a field and modeling study to investigate groundwater flow and the distribution of salinity during sea level rise in a domain that included beaches

Predicting mixing processes, especially transverse mixing, downstream of river confluences is necessary for assessing and modelling the fate of pollutants transported in river networks, but it is still challenging. Typically, there is a lack of transverse mixing solutions implemented in 1‐D hydrodynamical models widely used in river engineering applications. To investigate the mixing processes developing

This study proposes a new inverse algorithm to estimate the hydraulic conductivity (K ) distribution based on a Gaussian Mixture Model (GMM) that significantly reduces the number of parameters to be estimated during the inversion process. Moreover, a new objective function that increases the sensitivity of parameters using the spatial derivatives of hydraulic heads is introduced, and the algorithm

A comprehensive understanding of the combined effects of surface roughness and wettability on the dynamics of the trapping process is lacking. This can be primarily attributed to the contradictory experimental and numerical results regarding the impact of wettability on the capillary trapping efficiency. The discrepancy is presumably caused by the surface roughness of the inner pore‐solid interface

It has long been assumed that over a sufficiently long period of time, changes in catchment water storage (ΔS ) are a relatively minor term compared to other fluxes and can be neglected in the catchment water balance equation. However, the validity of this fundamental assumption has rarely been tested, and the associated uncertainties in water balance calculations remain unknown. Here, we use long‐term

The temporal variability of precipitation and potential evapotranspiration affects streamflow from daily to long‐term scales, but the relative roles of different climate variabilities on streamflow at daily, monthly, annual, and mean annual scales have not been systematically investigated in the literature. This paper developed a new daily water balance model, which provides a unified framework for

The planform evolution of tidal meanders is driven by interactions between channel morphology and periodically reversing tidal flows, which feed back into the development of erosional and depositional patterns. However, the paucity of quantitative data has so far undermined detailed analyses about the geomorphic effects of tidal flows within tidal meanders. Here we aim to bond the morphodynamic evolution

Formation dry‐out in fracture‐dominated geological reservoirs may alter the fracture space, impair rock absolute permeability and cause a significant decrease in well injectivity. In this study, we numerically model the dry‐out processes occurring during supercritical CO2 (scCO2) injection into single brine‐filled fractures and evaluate the potential for salt precipitation under increasing effective

Colloids are ubiquitous in groundwater systems, and understanding their behavior is of critical importance as they can pose a threat to human and environmental health. Extensive research has been conducted to model colloid behavior in fractures leading to the development of a number of analytical solutions, albeit for single fractures. However, the application of these analytical solutions at the network

Ensemble Forecast Operations (EFO) is a risk‐based approach of reservoir flood control operations that incorporates ensemble streamflow predictions (ESPs) made by the California‐Nevada River Forecast Center (CNRFC). Each member of an ESP is individually modeled to forecast system conditions and calculate risk of reaching critical operational thresholds. Reservoir release decisions are simulated to

The emergence of state‐of‐the‐art satellite altimetry has provided new prospects for integrating water surface elevation (water level) measurements with a hydrologic model for river discharge estimation, which is particularly suited for poorly gauged or ungauged basins. In this context, we explored the possibility of model calibration using Jason‐2‐derived water levels, followed by SWOT (the Surface

The “ecohydrologic separation” hypothesis challenged assumptions of translatory flow through the rooting zone. However, studies aiming to test ecohydrologic separation have largely done so with insufficient discussion of infiltration and rooting zone recharge processes and instead have mostly focused on either isotopic differences between stream water and plant water or the presence of fractionated