Water Resources Research is an open access journal that publishes original research articles and commentaries on hydrology, water resources, and the social sciences of water that provide a broad understanding of the role of water in Earth’s system.

In Memoriam: Harihar Rajaram
July 9, 2024

With deep sadness and an appreciation for his enormous contributions to the Earth and space sciences, AGU shares news of the loss of one of our esteemed, much-loved colleagues, Harihar Rajaram.

An AGU Fellow and longtime affiliate of the Hydrology Section, Dr. Rajaram was the Editor-in-Chief of Geophysical Research Letters (GRL) since 2019, a former editor on Water Resources Research (WRR), and served on the AGU Publications Committee.

Hari had a boundless energy. His thoughtfulness, diligence, dedication, sense of humor, and above all, his absolute kindness, will be missed. Even when dealing with the trickiest of situations on AGU journals, Hari never complained or quit. He found a way through bringing people together and finding solutions.

A professor in the Department of Environmental Health and Engineering at The Johns Hopkins University, Hari’s colleagues, Ed Schlesinger, the Benjamin T. Rome Dean and Department Chair Marsha Willis-Karp, shared the following remembrance.

The family obituary with many poignant remembrances is here with the suggestion of donations, in lieu of flowers, to the local Baltimore charity Beans and Bread.

Hari’s grounded perspective, exemplary scholarship, and warm friendship made a meaningful impact on all who knew him and worked beside him. May his memory leave a lasting impact on the Hydrology community and to his friends and colleagues around the world.



Water Resources Research is now a fully open access journal

AGU remains committed to open science and open data. As part of our mission, we are focused on making science available to the widest possible audience. With the growing open access requirements placed by funders on researchers around the world, this transition to an open access model also makes compliance easier.

All articles in the journal are open access as of 1 January 2024. For more information, including funding options for publishing fees, please visit the FAQ.

Browse Articles

Open access

Characterizing Aquifer Properties and Groundwater Storage at North China Plain Using Geodetic and Hydrological Measurements

  •  18 February 2025

Key Points

  • Geodetic observations reveal widespread and remarkable subsidence, with rate up to ∼120 mm/yr in North China Plain during 2015–2019

  • A comprehensive evaluation of aquifer properties and groundwater storage changes in the North China Plain is conducted using geodetic and hydrological data

  • Trend of subsidence in parts of North China Plain has slowed due to implementation of South-to-North Water Diversion Project

Open access

Declining Groundwater Storage in the Indus Basin Revealed Using GRACE and GRACE‐FO Data

  •  18 February 2025

Key Points

  • The rate of water storage declines in the Indus basin increased more than tripled from −0.65 cm/yr (2002–2015) to −2.16 cm/yr (2015–2022)

  • Groundwater storage in non-glaciated regions (−1.44 cm/yr) declined approximately twice as fast as in glaciated regions (−0.78 cm/yr)

  • Water availability in the Indus basin has declined due to reduced precipitation and runoff, coupled with increased ET and vegetation growth

Open access

Mapping Global Soil Moisture and Evapotranspiration Coupling Strength Based on a Two‐System Method and Multiple Data Sources

  •  17 February 2025

Key Points

  • A global map of soil moisture-evapotranspiration coupling strength (SECS) is regenerated

  • The new map is more advantageous since it is free of cross-correlated error

  • The overall SECS bias in the land surface models are previously overestimated

Open access

The Influence of Horizontal Dispersion on Residence Times in Shallow Lakes

  •  17 February 2025

Key Points

  • Circulation in lakes is investigated with numerical simulations

  • Shape of lakes largely influences tracer dispersions

  • The water residence time increases as dispersion increases owing to the scale of the lake

Open access

Controls of Climate Seasonality and Vegetation Dynamics on the Seasonal Variability of Terrestrial Water Storage Under Diverse Climate Regimes

  •  17 February 2025

Key Points

  • The in-phase (out-of-phase) P-PET relation reduces (enhances) ΔS seasonal variability

  • The growth of seasonal vegetation under in-phase P-PET relation can cope with limited soil water

  • The growth of evergreen vegetation under out-of-phase P-PET relation depends on soil water availability throughout the year

Open access

Efficient Implementation of Tidal Forcing in Simulations of Groundwater Dynamics in Subterranean Estuaries

  •  17 February 2025

Key Points

  • An efficient method for modeling the tidal signal during tidally affected Submarine groundwater discharge (SGD) simulation is presented

  • A single calibration factor gives good agreement between results for phase-averaged (PA) and phase-resolved (PR) simulations

  • The new method is verified by comparison of results for a wide range of physical cases

Open access

Tidal Influences on Temperature Dynamics and Heat Exchange in Coastal Wetlands

  •  17 February 2025

Key Points

  • Annual soil temperature ranges are altered by interactions of tides and macropores

  • Tide-induced conductive heat flux produces more net effects on heat balance than advective flow

  • Macropores enhance local temperature fluctuations by augmenting advective heat exchange and increasing heat capacity

Open access

Global Applicability of the Kappa Distribution for Rainfall Frequency Analysis

  •  17 February 2025

Key Points

  • The four-parameter Kappa distribution was fitted to a global data set of annual maxima rainfall

  • Variation in the second shape parameter ( h $h$ ) was examined across regime characteristics, geospatial regions, and climate regional groupings

  • h was found to be non-zero (i.e., to depart from the Generalised Extreme Value distribution) in regions with few average annual rain days

Open access

Effects of Grass Cover on the Overland Soil Erosion Mechanism Under Simulated Rainfall

  •  16 February 2025

Key Points

  • Systematically analyze the response mechanism of overland soil erosion concerning experimental design factors and hydrodynamic variables

  • Dimensionless stream power is the most effective hydrodynamic parameters for predicting overland soil erosion under grass cover

  • Develop an overland soil erosion prediction model using general dimensionless flow strength parameters

Open access

Multi‐Physics Data Assimilation Framework for Remotely Sensed Snowpacks to Improve Water Prediction

  •  16 February 2025

Key Points

  • Dual evaluation of physical and radiative properties of modeled snowpack

  • Assimilation of SWE reduced model bias and reconstructed spatial heterogeneity

  • Assimilation improved vertical profile of snowpack density

More articles
Open access

A Transdisciplinary Review of Deep Learning Research and Its Relevance for Water Resources Scientists

Key Points

  • Deep learning (DL) is transforming many scientific disciplines, but its adoption in hydrology is gradual
  • DL can help tackle interdisciplinarity, data deluge, unrecognized linkages, and long-standing challenges such as scaling and equifinality
  • The new field of AI neuroscience opens up many opportunities for scientists to use DL as an exploratory tool for scientific advancement

Open access

MERIT Hydro: A High‐Resolution Global Hydrography Map Based on Latest Topography Dataset

Key Points

  • A global hydrography map was generated using the latest topography dataset
  • Near-automatic algorithm applicable for global hydrography delineation was developed
  • Adjusted elevation and river width layers consistent with flow direction map are provided

free access

A Rainfall‐Runoff Model With LSTM‐Based Sequence‐to‐Sequence Learning

Key Points

  • An hourly runoff model was developed using the LSTM sequence-to-sequence learning method for 24-hr predictions on USGS stations
  • The proposed model shows better performance than traditional data-driven models and is applicable to different watersheds
  • The advantages and limitations of seq2seq models and how this model structure could work on the rainfall-runoff modeling is presented

More articles
free access

Investigating the Propagation From Meteorological to Hydrological Drought by Introducing the Nonlinear Dependence With Directed Information Transfer Index

Key Points

  • Directed information transfer index was introduced in drought propagation study to build a new drought response time evaluation system for the first time

  • Trigger thresholds from meteorological to hydrological drought were determined by a drought propagation model

  • Sub-regions with smaller meteorological drought trigger thresholds had longer durations of hydrological drought events

Open access

Water Use in Global Livestock Production—Opportunities and Constraints for Increasing Water Productivity

Key Points

  • Annually, 4,387 km3 of water is required to produce the feed consumed by the global livestock sector, of which 94% is green water
  • Opportunities for increasing livestock water productivity exist for all livestock types but are particularly large for ruminants
  • Water productivity improvements for ruminants through supplementation with feed crops are constrained by high water cost to produce crops

free access

The science and practice of river restoration

Key Points

  • River restoration is a prominent area of applied water-resources science
  • restoration includes connectivity, physical-biotic interactions, and history
  • effective restoration requires collaboration among scientists and practitioners

free access

Status of CO2 storage in deep saline aquifers with emphasis on modeling approaches and practical simulations

Key Points:

  • Carbon storage in deep saline aquifers is a viable carbon mitigation option
  • A wide range of modeling approaches can provide practical simulation results
  • Field-scale observations and modeling enhance system understanding

free access

A Method for Objectively Integrating Soil Moisture Satellite Observations and Model Simulations Toward a Blended Drought Index

Key Points

  • Develop a viable approach to validate the satellite soil moisture products
  • Translate model and satellite soil moisture into useful information for drought monitoring
  • An objective blended drought index is recommended

Open access

Global Groundwater Modeling and Monitoring: Opportunities and Challenges

Key Points

  • A global groundwater framework is needed to address critical gaps in our understanding and predictive capacity of the hydrologic cycle

  • We envision a framework that will combine observations and models to provide spatially and temporally continuous groundwater information

  • The proposed framework could improve predictability in existing models and provide valuable new information for water management

Plain Language Summary

Groundwater is an important part of the water cycle but we are still working on the best ways to include it in global models. This study provides an overview of the state of the science for groundwater modeling and outlines a road map for what is needed to improve global groundwater models.

Open access

Satellite Remote Sensing for Water Resources Management: Potential for Supporting Sustainable Development in Data‐Poor Regions

Key Points

  • Satellite remote sensing is being incorporated into water resources management but is generally underutilized
  • New and proposed missions have the potential to transform water resources management for sustainable development, especially in data-poor regions
  • Ongoing challenges of accuracy, sampling, and continuity and capacity development need to be addressed, as well as new challenges of information volume and diversity

Open access

Remote Sensing of Groundwater: Current Capabilities and Future Directions

Key Points

  • Accurately measuring and monitoring groundwater storage and fluxes is critical for water, food, and energy security

  • Remote sensing approaches such as gravitational measurements, Interferometric Synthetic Aperture Radar, Global Navigational Satellite System, lidar altimetry, and Airborne Electromagnetic Systems can yield indirect yet valuable information about groundwater

  • Fusing multiple remotely sensed data sets or employing other tools such as numerical models increase the applicability of individual approaches

free access

ChatGPT in Hydrology and Earth Sciences: Opportunities, Prospects, and Concerns

Key Points

  • Large language models (LLMs) such as ChatGPT, are new technological tools that might fundamentally change academia

  • ChatGPT can assist in academic writing but should not be relied on as the only source of information in hydrology and Earth Science studies

  • Authors should exhibit transparency in their utilization of LLMs and uphold ethical responsibility

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