Hydrology

  • Article
    | Open Access

    The global water demands of irrigated agriculture are estimated through country surveys or through hydrological models, but both approaches are taxing. Here, the authors show that they can simply be estimated as a function of irrigated areas.

    • Arnald Puy
    • , Emanuele Borgonovo
    •  & Andrea Saltelli
  • Article
    | Open Access

    A historical reconstruction of water use in Egypt shows the change in relative use of Nile water versus virtual water import, especially in the highly consumptive agriculture sector. A range of future projections of water demand are offered based on several plausible socioeconomic scenarios.

    • Catherine A. Nikiel
    •  & Elfatih A. B. Eltahir
  • Article
    | Open Access

    Freshwater salinisation is a growing water quality problem, but impacts and drivers across regional to global scales have been lacking. A new assessment of inter-regional freshwater salinisation demonstrates the importance of irrigation as a driver of salinisation.

    • Josefin Thorslund
    • , Marc F. P. Bierkens
    •  & Michelle T. H. van Vliet
  • Article
    | Open Access

    Microbes that colonise ice sheet surfaces are important to the carbon cycle, but their biomass and transport remains unquantified. Here, the authors reveal substantial microbial carbon fluxes across Greenland’s ice surface, in quantities that may sustain subglacial heterotrophs and fuel methanogenesis.

    • T. D. L. Irvine-Fynn
    • , A. Edwards
    •  & A. Hubbard
  • Article
    | Open Access

    Jiao et al. conducted a comprehensive evaluation of changes in water constraint on vegetation growth in the extratropical Northern Hemisphere between 1982 and 2015. They document a significant increase in vegetation water constraint over the last three decades.

    • Wenzhe Jiao
    • , Lixin Wang
    •  & Paolo D’Odorico
  • Article
    | Open Access

    Filling of dams, when coinciding with droughts, can lead to severe downstream hydrology and ecology problems. The authors hence here provide a multisectoral perspective, using a dam in Ethiopia as an example, to develop adaptive filling solutions that support decision making, favourable filling timing and an effective filling policy.

    • Marta Zaniolo
    • , Matteo Giuliani
    •  & Andrea Castelletti
  • Article
    | Open Access

    Glaciers in High Mountain Asia are a key water resource. The authors use remote sensing data and a regional implementation of the continuity equation to quantify glacier ablation and accumulation rates for 2000–2016, and establish current climatic-geometric imbalances that imply strong reductions in ice volume by 2100.

    • Evan Miles
    • , Michael McCarthy
    •  & Francesca Pellicciotti
  • Article
    | Open Access

    Most studies have examined the impacts of human-driven climate change on mean or extreme climate variables and have neglected to explore interrelated drought features. Here, the authors show that the presence of human activity has increased the number and maximum length and intensity of drought events across the globe.

    • Felicia Chiang
    • , Omid Mazdiyasni
    •  & Amir AghaKouchak
  • Article
    | Open Access

    The authors investigate the impacts of wildfires on fluvial networks in the western US. They find that wildfires directly impacted ~6% of the total stream length between 1984 and 2014. When longitudinal propagation was included, they estimate that wildfires affected ~11% of the total stream length.

    • Grady Ball
    • , Peter Regier
    •  & David Van Horn
  • Article
    | Open Access

    The long-term impact of extreme surface melt on the Greenland Ice Sheet is poorly constrained. Here the authors use airborne radar to characterize a subsurface refrozen melt layer that formed following extreme melt in 2012, showing that it likely reduced drainage pathways for subsequent melt.

    • Riley Culberg
    • , Dustin M. Schroeder
    •  & Winnie Chu
  • Article
    | Open Access

    The impacts of water scarcity depend on physical basin characteristics and global economic dynamics. Here, the authors show scenario assumptions can yield either highly positive or negative economic impacts due to water scarcity, and the drivers of these impacts are basin-specific and cannot be determined a priori.

    • Flannery Dolan
    • , Jonathan Lamontagne
    •  & Jae Edmonds
  • Article
    | Open Access

    Based on the analysis of chemical maps of Thorium and Potassium derived in the Eridania region on Mars, the authors show how radiogenic heat driven hydrothermal systems may have persisted on Mars.

    • Lujendra Ojha
    • , Suniti Karunatillake
    •  & Jacob Buffo
  • Article
    | Open Access

    Groundwater discharge generates streamflow and influences stream thermal regimes. Classifying more than 1700 streams across the US by using an empirically-based approach the study shows that the vulnerability of streams to stressors depends on the aquifer source-depth of groundwater discharge

    • Danielle K. Hare
    • , Ashley M. Helton
    •  & Martin A. Briggs
  • Article
    | Open Access

    Global flood risk is assessed in this study; in particular, the authors describe, based on a modeling approach, the positive effect of river dams on mitigating flood hazards to people.

    • Julien Boulange
    • , Naota Hanasaki
    •  & Yadu Pokhrel
  • Article
    | Open Access

    Groundwater discharge is a mechanism that transports chemicals from inland systems to the ocean, but it has been considered of secondary influence compared to rivers. Here the authors assess the global significance of groundwater discharge, finding that it has a unique and important contribution to ocean chemistry and Earth-system models.

    • Kimberley K. Mayfield
    • , Anton Eisenhauer
    •  & Adina Paytan
  • Article
    | Open Access

    Excess fertilizer use causes subsurface contamination. Here, the authors conduct an assessment of water quality vulnerability across Europe, finding that 75% of agricultural regions are susceptible to nitrate contamination for least one-third of the year, two times more than using standard estimation procedure.

    • R. Kumar
    • , F. Heße
    •  & S. Attinger
  • Article
    | Open Access

    This study investigates flood hazards of the Brahmaputra River, Bangladesh. Based on a tree ring reconstruction of seasonal river discharge, climate modelling, and historic documentation of flood events, the authors suggest flood hazard risk is underestimated by ~24–38% in the present day compared to the past 700 years.

    • Mukund P. Rao
    • , Edward R. Cook
    •  & Peter J. Webster
  • Article
    | Open Access

    Monsoon systems have strong impacts on precipitation and food security over large areas of the world. Here, the authors show that plant responses to rising CO2 concentrations in the atmosphere play a key role in modulating seasonal rainfall and water resources over global land monsoon regions.

    • Jiangpeng Cui
    • , Shilong Piao
    •  & Gabriel J. Kooperman
  • Article
    | Open Access

    Trough mouth fans are created via repeated glacigenic sediment transport from ice sheets. Here the authors use 3D seismic reflection data to present a formation model for the North Sea Fan and find that exceptionally large volumes of meltwater may mean that freshwater supply is underestimated during glacial cycles.

    • Benjamin Bellwald
    • , Sverre Planke
    •  & Reidun Myklebust
  • Article
    | Open Access

    The hydroclimatic variations of the Amazon River basin can exert profound impacts on the marine ecosystem in the Amazon plume region. Here the authors show that an amplified seasonal cycle of Amazonia precipitation during 1979–2018 leads to enhanced seasonality in both Amazon river discharge and ocean salinity.

    • Yu-Chiao Liang
    • , Min-Hui Lo
    •  & John D. Steffen
  • Article
    | Open Access

    Prior studies mapping climatologically suitable areas for malaria transmission have used relatively simple thresholds for precipitation. Here the authors show that when models incorporate hydrological processes a more complex pattern of malaria suitability emerges in Africa and future shifts in suitability are more pronounced.

    • M. W. Smith
    • , T. Willis
    •  & C. J. Thomas
  • Article
    | Open Access

    Climate change may impact groundwater storage and thus the availability of freshwater resources. Here the authors use climate models to examine seven aquifers and find that storage changes are primarily the result of enhancement of evapotranspiration, reduction in snowmelt, and over-pumping rather than long-term precipitation changes.

    • Wen-Ying Wu
    • , Min-Hui Lo
    •  & Zong-Liang Yang
  • Article
    | Open Access

    The authors here address water sustainability in the greater area of Beijing, China. Specifically, the positive effects towards Beijing groundwater levels via water diversion from the Yangtze River to the North are shown.

    • Di Long
    • , Wenting Yang
    •  & Yoshihide Wada
  • Article
    | Open Access

    Assessments of future virtual water trading are still lacking. Here the authors estimated the global virtual water trade throughout the century and found that virtual green water exports and virtual blue water exports at least triple to more than 3200 bcm and 170 bcm, respectively, by the end of the century.

    • Neal T. Graham
    • , Mohamad I. Hejazi
    •  & Fernando Miralles-Wilhelm
  • Article
    | Open Access

    Biomonitoring via environmental DNA (eDNA) is an important conservation tool for freshwater ecosystems, but this is complicated by eDNA movement downstream. Here, Carraro et al. develop and test an approach to reconstruct high-resolution spatial biodiversity patterns from freshwater eDNA.

    • Luca Carraro
    • , Elvira Mächler
    •  & Florian Altermatt
  • Article
    | Open Access

    The authors of this study compile data on spatial and temporal dynamics of surface water bodies across China, covering a time span from 1989 – 2016. The study describes hot-spot areas with strongly decreasing trends in surface water area and terrestrial water storage in North China and discusses implications of water resources and security in China.

    • Xinxin Wang
    • , Xiangming Xiao
    •  & Bo Li
  • Article
    | Open Access

    Studies on examining the climate impact on irrigated agriculture do not account for regional specific details. Here the authors studied both the direct and indirect impact of climate change on irrigated agriculture in the Yakima River Basin (YRB) and found that increasingly severe droughts and temperature driven reductions in growing season significantly reduces expected annual agricultural productivity.

    • Keyvan Malek
    • , Patrick Reed
    •  & Michael Brady
  • Article
    | Open Access

    Anomalously specular radar reflections (ASRR) from Titan’s tropical region were interpreted earlier as evidence for liquid surfaces, but the Cassini spacecraft did not observe lakes/seas at the anomalously specular locations. Here, the authors show that ASRR originate from one terrain unit, likely paleolakes/paleoseas.

    • Jason D. Hofgartner
    • , Alexander G. Hayes
    •  & Stephen D. Wall
  • Article
    | Open Access

    Floods are an important natural disaster on the Indonesian island of Sumatra, but their driving mechanisms are not well understood. Here, the authors utilize data from twitter messages and local newspaper reports to show that convectively coupled Kelvin waves play a key role in promoting floods on Sumatra.

    • Dariusz B. Baranowski
    • , Maria K. Flatau
    •  & Marzuki
  • Article
    | Open Access

    The impacts of power plant water shortage during drought on electricity prices are understudied. Here the authors show that on extreme days, almost 50% (7 GWe) of the freshwater thermal capacity is unavailable in the Great Britain and annualized cumulative costs on electricity prices are in the range of £29-95m per year.

    • Edward A. Byers
    • , Gemma Coxon
    •  & Jim W. Hall
  • Article
    | Open Access

    Generally it is thought that confining clay layers provide protection to low-arsenic groundwaters against intrusion of shallower, high-arsenic groundwater bodies. Here, the authors show that impermeable clay layers can increase arsenic input to underlying groundwater systems due to reduction of iron oxides coupled to carbon oxidation.

    • Ivan Mihajlov
    • , M. Rajib H. Mozumder
    •  & Alexander van Geen
  • Article
    | Open Access

    Siberian Arctic permafrost contains vast stores of carbon, the fate of which is dependent on the climate. Here the authors use models of future scenarios to show that under the direst climate changes up to 2/3 of the stored organic carbon could thaw.

    • Jan Nitzbon
    • , Sebastian Westermann
    •  & Julia Boike
  • Article
    | Open Access

    Tropical cyclones can cause severe flooding when making landfall, but these water flows can often only be forecasted a few hours before. Here, the authors present a new approach using self-organizing maps and flow characteristic curves to predict tropical cyclone related runoff up to two days in advance.

    • Li-Chiu Chang
    • , Fi-John Chang
    •  & Edwin E. Herricks
  • Article
    | Open Access

    The authors investigate the infiltration potential of more than 500 vacant lots in the City of Buffalo, NY, USA. They found that the expanding footprint of pervious cover as urban vacant land provides stormwater volume retention benefits on an event and annual basis.

    • Christa Kelleher
    • , Heather E. Golden
    •  & William Shuster
  • Article
    | Open Access

    In this study, the authors show that water flowing through thawed soils below the tundra surface (supra-permafrost groundwater) can be a major source of dissolved organic matter (DOM) to Arctic coastal waters during the summer. This DOM contains leachates from old soil carbon stocks, including potential contributions from thawing permafrost.

    • Craig T. Connolly
    • , M. Bayani Cardenas
    •  & James W. McClelland
  • Article
    | Open Access

    Economic estimates of flood damages rely on depth–damage functions that are inadequately verified. Here, the authors assessed flood vulnerability in the US and found that current depth–damage functions consist of disparate relationships that match poorly with observations which better follow a bimodal beta distribution.

    • Oliver E. J. Wing
    • , Nicholas Pinter
    •  & Carolyn Kousky
  • Article
    | Open Access

    The authors here combine a range of geophysical data, numerical modelling and borehole data to present a high resolution map of an offshore freshened groundwater system in the Canterbury Bight, New Zealand. The study shows the extensions of the offshore freshened groundwater system to be controlled by high permeability shelf sediments, buried paleochannels and onshore rivers.

    • Aaron Micallef
    • , Mark Person
    •  & Ashwani Kumar Tiwari