WaterGAP

Last updated

The global freshwater model WaterGAP calculates flows and storages of water on all continents of the globe (except Antarctica), taking into account the human influence on the natural freshwater system by water abstractions and dams. It supports understanding the freshwater situation across the world's river basins during the 20th and the 21st centuries, and is applied to assess water scarcity, droughts and floods and to quantify the impact of human actions on e.g. groundwater, wetlands, streamflow and sea-level rise. Modelling results of WaterGAP have contributed to international assessment of the global environmental situation including the UN World Water Development Reports, the Millennium Ecosystem Assessment, the UN Global Environmental Outlooks as well as to reports of the Intergovernmental Panel on Climate Change. WaterGAP contributes to the Intersectoral Impact Model Intercomparison Project ISIMIP, [1] where consistent ensembles of model runs by a number of global hydrological models are generated to assess the impact of climate change and other anthropogenic stressors on freshwater resources world-wide.

Contents

WaterGAP (WaterGlobal Assessment and Prognosis) [2] [3] was developed at the University of Kassel (Germany) [4] since 1996, while later on development has continued at Goethe University Frankfurt [5] and Ruhr University Bochum. It consists of both the WaterGAP Global Hydrology Model (WGHM) [6] [7] and five water use models for the sectors irrigation, [8] livestock, households, manufacturing and cooling of thermal power plants. [9] An additional model component computes the fractions of total water use that are abstracted from either groundwater or surface waters (rivers, lakes and reservoirs). [10] The model runs with a temporal resolution of 1 day; WaterGAP 2 has a spatial resolution of 0.5 degree geographical latitude × 0.5 degree geographical longitude (equivalent to 55 km × 55 km at the equator) [3] and WaterGAP 3 a spatial resolution of 5 arc minutes x 5 arc minutes (9 km x 9 km). [11] Model input includes time series of climate data (e.g. precipitation, temperature and radiation) and information such as characteristics of surface water bodies (lakes, reservoirs and wetlands), land cover, soil type, topography and irrigated area.

WaterGAP Global Hydrology Model WGHM

Water storages (boxes) and flows (arrows) modelled for each grid cell of WGHM WaterGAP WGHM Computed Water Storages and Flows.jpg
Water storages (boxes) and flows (arrows) modelled for each grid cell of WGHM

WGHM computes time-series of fast-surface and subsurface runoff, groundwater recharge and river discharge as well as storage variations of water in canopy, snow, soil, groundwater, lakes, wetlands and rivers. [3] Thus, it quantifies the total renewable water resources as well as the renewable groundwater resources of a grid cell, river basin, or country. Precipitation on each grid cell is transported through the different storage compartments, where water can also evapotranspirate. Location and size of wetlands, lakes and reservoirs are defined by the global lakes and wetland database (GLWD), [12] and the GRanD database of man-made reservoirs. [13] [14] Groundwater storage is affected by diffuse groundwater recharge through the soil and by point recharge from surface water bodies. [10] Diffuse groundwater recharge is modeled as a function of total runoff, relief, soil texture, hydrogeology and the existence of permafrost or glaciers. [7] Cell runoff is routed downstream until it reaches the ocean or an internal sink. To allow a plausible representation of the actual freshwater situation, version 2.2d of WGHM is tuned against observed long-term mean annual streamflow at 1319 gauging stations. [3] Performance of WGHM with respect to streamflow observations has been compared in various studies to that of other global hydrological models for both Europe [15] [16] and the globe, [17] [18] [19] [20] while performance with respect to GRACE total water storage anomaly was compared globally [21] [22] and for U.S. aquifers. [23]

Total Renewable Water Resources by WaterGAP in mm per year.png
Total renewable water resources, in mm/yr (1 mm is equivalent to 1 L of water per m2) (average 1981-2010). [3]
Total Renewable GroundwaterResources by WaterGAP in mm per year.png
Total renewable groundwater resources, in mm/yr (1 mm is equivalent to 1 L of water per m2) (average 1981-2010), which are a part of the total renewable freshwater resources and the maximum that can be abstracted without depleting the groundwater. [3]

Water Use Models

In WaterGAP, modeling of water use refers to computation of water withdrawals (abstractions) from either groundwater or surface water bodies (lakes, reservoirs and rivers), of consumptive water uses (the fraction of the abstracted water that evapotranspires during use) and of the return flows to groundwater or surface water bodies. Consumptive irrigation water use is computed by the Global Irrigation Model [8] [24] as a function of irrigated area [25] and climate in each grid cell. Livestock water use is calculated as a function of the animal numbers and water requirements of different livestock types. Domestic and manufacturing use are based on national values of water withdrawals at different points in time. [9] The temporal development of national household water use is based on statistical data modeled as a function of technological and structural change (the latter as a function of gross domestic product), taking into account population change. The temporal development of manufacturing water use takes into account technological change and the development of manufacturing gross value added. National values of domestic and manufacturing water use are downscaled to the grid cells using population density and urban population density, respectively. [9] Water use for cooling of thermal power plants takes into account the location and characteristics of thermal power plants. [9] Time series of monthly values of irrigation water use are computed, while all other uses are assumed to be constant throughout the year and to only vary from year to year. Based on sectoral water withdrawals and consumptive use as computed by the five water use models, the model component GWSWUSE calculates surface water abstractions from and return flows to groundwater and surface water as well as the total net abstraction from groundwater and from surface water in each grid cell. [10]

Development of Water Abstractions and Water Consumption by WaterGAP.png
Development of water abstractions (sum of return flows and consumptive use) and water consumption (the amount of water that is evapotranspired or incorporated in products, light colours) of the five water use sectors considered in WaterGAP for 1901–2010 [26]
Total Water Withdrawals in mm per year By WaterGAP Average 1998-2002.jpg
Water withdrawals around the year 2000, in mm/yr. [10]

Applications

WaterGAP has been applied to assess which areas of the world are and will be affected by water stress, and to estimate the world's freshwater balance. [3] In many studies, WaterGAP served to estimate the impact of climate change on the global freshwater system, e.g. on groundwater, [27] [28] [29] wetlands, [30] streamflow [31] [32] [33] [34] and irrigation requirements. [35] Groundwater stress and depletion of groundwater resources were analyzed. [36] [37] In addition, the alteration of ecologically relevant river flow characteristics and wetland dynamics due to human water use and dams was studied. [13] [30] Time series of WaterGAP total water storage anomalies were used to process and interpret GRACE (Gravity Recovery and Climate Experiment) satellite measurement of the dynamic gravity of the Earth, as for the continents, the seasonal and longer-term gravity changes are to a large extent caused by changes of the water stored in groundwater, surface waters, soil and snow. [38] [39] These time series also served to estimate the contribution of water storage variations on the continents to sea level rise. [40] [41] WaterGAP results are also used in life-cycle assessments to take into account water stress at production sites. [42]

Groundwater Withdrawals in 2010 by WaterGAP in Percent of Renewable Groundwater Resources.jpg
Groundwater stress: Groundwater withdrawals in 2010 in percent of renewable groundwater resources. Purple regions are likely to suffer from groundwater depletion, with declining groundwater tables. [37]
Global Values of Water Resources and Water Use.jpg
Global values of water resources and human water use (excluding Antarctica). Water resources 1961-90, water use around 2000.

Related Research Articles

<span class="mw-page-title-main">Hydrology</span> Science of the movement, distribution, and quality of water on Earth and other planets

Hydrology is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.

<span class="mw-page-title-main">Evapotranspiration</span> Process by when water moves into the air from plants and soil.

Evapotranspiration (ET) is the combined processes which move water from the Earth's surface into the atmosphere. It covers both water evaporation and transpiration. Evapotranspiration is an important part of the local water cycle and climate, and measurement of it plays a key role in agricultural irrigation and water resource management.

<span class="mw-page-title-main">Water cycle</span> Continuous movement of water on, above and below the surface of the Earth

The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, transpiration, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and vapor. The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation.

<span class="mw-page-title-main">Groundwater</span> Water located beneath the ground surface

Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology.

<span class="mw-page-title-main">Environmental degradation</span> Any change or disturbance to the environment perceived to be deleterious or undesirable

Environmental degradation is the deterioration of the environment through depletion of resources such as quality of air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. It is defined as any change or disturbance to the environment perceived to be deleterious or undesirable.

In the field of hydrogeology, storage properties are physical properties that characterize the capacity of an aquifer to release groundwater. These properties are storativity (S), specific storage (Ss) and specific yield (Sy). According to Groundwater, by Freeze and Cherry (1979), specific storage, [m−1], of a saturated aquifer is defined as the volume of water that a unit volume of the aquifer releases from storage under a unit decline in hydraulic head.

<span class="mw-page-title-main">Water balance</span> Looks at how water moves in a closed system

The law of water balance states that the inflows to any water system or area is equal to its outflows plus change in storage during a time interval. In hydrology, a water balance equation can be used to describe the flow of water in and out of a system. A system can be one of several hydrological or water domains, such as a column of soil, a drainage basin, an irrigation area or a city.

<span class="mw-page-title-main">HBV hydrology model</span>

The HBV hydrology model, or Hydrologiska Byråns Vattenbalansavdelning model, is a computer simulation used to analyze river discharge and water pollution. Developed originally for use in Scandinavia, this hydrological transport model has also been applied in a large number of catchments on most continents.

<span class="mw-page-title-main">Groundwater recharge</span> Groundwater that recharges an aquifer

Groundwater recharge or deep drainage or deep percolation is a hydrologic process, where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and is often expressed as a flux to the water table surface. Groundwater recharge also encompasses water moving away from the water table farther into the saturated zone. Recharge occurs both naturally and through anthropogenic processes, where rainwater and or reclaimed water is routed to the subsurface.

<span class="mw-page-title-main">Overdrafting</span> Unsustainable extraction of groundwater

Overdrafting is the process of extracting groundwater beyond the equilibrium yield of an aquifer. Groundwater is one of the largest sources of fresh water and is found underground. The primary cause of groundwater depletion is the excessive pumping of groundwater up from underground aquifers.

<span class="mw-page-title-main">Intermittent river</span> River that periodically ceases to flow

Intermittent, temporary or seasonal rivers or streams cease to flow every year or at least twice every five years. Such rivers drain large arid and semi-arid areas, covering approximately a third of the earth's surface. The extent of temporary rivers is increasing, as many formerly perennial rivers are becoming temporary because of increasing water demand, particularly for irrigation. Despite inconsistent water flow, intermittent rivers are considered land-forming agents in arid regions, as they are agents of significant deposition and erosion during flood events. The combination of dry crusted soils and the highly erosive energy of the rain cause sediment resuspension and transport to the coastal areas. They are among the aquatic habitats most altered by human activities. During the summer even under no flow conditions the point sources are still active such as the wastewater effluents, resulting in nutrients and organic pollutants accumulating in the sediment. Sediment operates as a pollution inventory and pollutants are moved to the next basin with the first flush. Their vulnerability is intensified by the conflict between water use demand and aquatic ecosystem conservation. Advanced modelling tools have been developed to better describe intermittent flow dynamic changes such as the tempQsim model.

<span class="mw-page-title-main">Water scarcity</span> Lack of fresh water resources to meet water demand

Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity namely physical and economic water scarcity. Physical water scarcity is where there is not enough water to meet all demands, including that needed for ecosystems to function. Arid areas for example Central Asia, West Asia, and North Africa often experience physical water scarcity. Economic water scarcity on the other hand, is the result of lack of investment in infrastructure or technology to draw water from rivers, aquifers, or other water sources. It also results from weak human capacity to meet water demand. Much of Sub-Saharan Africa experiences economic water scarcity.

<span class="mw-page-title-main">Water resources</span> Sources of water that are potentially useful

Water resourcesare natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on Earth is salt water and only three percent is fresh water; slightly over two-thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of fresh water include surface water, under river flow, groundwater and frozen water. Artificial sources of fresh water can include treated wastewater and desalinated seawater. Human uses of water resources include agricultural, industrial, household, recreational and environmental activities.

SWAT is a river basin scale model developed to quantify the impact of land management practices in large, complex watersheds. SWAT is a public domain software enabled model actively supported by the USDA Agricultural Research Service at the Blackland Research & Extension Center in Temple, Texas, USA. It is a hydrology model with the following components: weather, surface runoff, return flow, percolation, evapotranspiration, transmission losses, pond and reservoir storage, crop growth and irrigation, groundwater flow, reach routing, nutrient and pesticide loading, and water transfer. SWAT can be considered a watershed hydrological transport model. This model is used worldwide and is continuously under development. As of July 2012, more than 1000 peer-reviewed articles have been published that document its various applications.

<span class="mw-page-title-main">Water security</span> A goal of water management to harness water-related opportunities and manage risks

The aim of water security is to make the most of water's benefits for humans and ecosystems. The second aim is to limit the risks of destructive impacts of water to an acceptable level. These risks include for example too much water (flood), too little water or poor quality (polluted) water. People who live with a high level of water security always have access to "an acceptable quantity and quality of water for health, livelihoods and production". For example, access to water, sanitation and hygiene services is one part of water security. Some organizations use the term water security more narrowly for water supply aspects only.

<span class="mw-page-title-main">Endorheic lake</span> Depression within an endorheic basin where water collects with no visible outlet

An endorheic lake is a collection of water within an endorheic basin, or sink, with no evident outlet. Endorheic lakes are generally saline as a result of being unable to get rid of solutes left in the lake by evaporation. These lakes can be used as indicators of anthropogenic change, such as irrigation or climate change, in the areas surrounding them. Lakes with subsurface drainage are considered cryptorheic.

James S. (Jay) Famiglietti is the director of the Global Institute for Water Security at the University of Saskatchewan in Saskatoon, Canada. Prior to that he was the Senior Water Scientist at NASA Jet Propulsion Laboratory in Pasadena, CA and a professor of Earth System Science at the University of California, Irvine. He is a leading expert in global water issues and in raising awareness about the global water crisis and in particular, about global groundwater depletion.

Petra Döll is a German hydrologist whose work focuses on modeling global water resources. She is a professor of hydrology and researcher at the Institute of Physical Geography, Goethe University Frankfurt.

<span class="mw-page-title-main">Fresh water</span> Naturally occurring water with low amounts of dissolved salts

Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non-salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans.

<span class="mw-page-title-main">Effects of climate change on the water cycle</span>

The effects of climate change on the water cycle are profound and have been described as an intensification or a strengthening of the water cycle. This effect has been observed since at least 1980. One example is the intensification of heavy precipitation events. This has important negative effects on the availability of freshwater resources, as well as other water reservoirs such as oceans, ice sheets, atmosphere and land surface. The water cycle is essential to life on Earth and plays a large role in the global climate and the ocean circulation. The warming of our planet is expected to cause changes in the water cycle for various reasons. For example, warmer atmosphere can contain more water vapor which has effects on evaporation and rainfall.

References

  1. "The Inter-Sectoral Impact Model Intercomparison Project". ISIMIP. Retrieved 2022-02-28.
  2. Alcamo, J., Döll, P., Henrichs, T., Kaspar, F., Lehner, B., Rösch, T., Siebert, S. (2003): Development and testing of the WaterGAP 2 global model of water use and availability. Hydrological Sciences Journal, 48(3), 317-338.
  3. 1 2 3 4 5 6 7 8 Müller Schmied, Hannes; Cáceres, Denise; Eisner, Stephanie; Flörke, Martina; Herbert, Claudia; Niemann, Christoph; Peiris, Thedini Asali; Popat, Eklavyya; Portmann, Felix Theodor; Reinecke, Robert; Schumacher, Maike (2021-02-23). "The global water resources and use model WaterGAP v2.2d: model description and evaluation". Geoscientific Model Development. 14 (2): 1037–1079. Bibcode:2021GMD....14.1037M. doi: 10.5194/gmd-14-1037-2021 . hdl: 11250/2984567 . ISSN   1991-9603.
  4. "Goethe-Universität — WaterGAP". www.uni-frankfurt.de. Retrieved 2022-04-20.
  5. "Goethe-Universität — WaterGAP". www.uni-frankfurt.de. Retrieved 2021-08-29.
  6. Döll, P., Kaspar, F., Lehner, B. (2003): A global hydrological model for deriving water availability indicators: model tuning and validation. Journal of Hydrology, 270 (1-2), 105-134.
  7. 1 2 Döll, P., Fiedler, K. (2008): Global-scale modeling of groundwater recharge. Hydrol. Earth Syst. Sci., 12, 863-885.
  8. 1 2 Döll, P., Siebert, S. (2002): Global modeling of irrigation water requirements. Water Resources Research, 38(4), 8.1-8.10, doi : 10.1029/2001WR000355
  9. 1 2 3 4 Flörke, Martina; Kynast, Ellen; Bärlund, Ilona; Eisner, Stephanie; Wimmer, Florian; Alcamo, Joseph (February 2013). "Domestic and industrial water uses of the past 60 years as a mirror of socio-economic development: A global simulation study". Global Environmental Change. 23 (1): 144–156. doi:10.1016/j.gloenvcha.2012.10.018.
  10. 1 2 3 4 Döll, P., Hoffmann-Dobrev, H., Portmann, F.T., Siebert, S., Eicker, A., Rodell, M., Strassberg, G., Scanlon, B. (2012): Impact of water withdrawals from groundwater and surface water on continental water storage variations. J. Geodyn. 59-60, 143-156, doi : 10.1016/j.jog.2011.05.001
  11. Eisner, S. (2015): Comprehensive evaluation of the WaterGAP3 model across climatic, physiographic, and anthropogenic gradients. PhD dissertation, University of Kassel, Germany
  12. Lehner, B., Döll, P. (2004): Development and validation of a database of lakes, reservoirs and wetlands. Journal of Hydrology, 296 (1-4), 1-22.
  13. 1 2 Döll, P., Fiedler, K., Zhang, J. (2009): Global-scale analysis of river flow alterations due to water withdrawals and reservoirs. Hydrol. Earth Syst. Sci., 13, 2413-2432.
  14. Lehner, B., Reidy Liermann, C., Revenga, C., Vörösmary, C., Fekete, B., Crouzet, P., Döll, P., Endejan, M., Frenken, K., Magome, J., Nilsson, C., Robertson, J.C., Rödel, R., Sindorf, N., Wisser, D. (2011): High resolution mapping of the world's reservoirs and dams for sustainable river flow management. Frontiers in Ecology and the Environment, 9(9), 494-502.
  15. Gudmundsson, L., T. Wagener, L. M. Tallaksen, and K. Engeland (2012), Evaluation of nine large-scale hydrological models with respect to the seasonal runoff climatology in Europe, Water Resour. Res., 48, W11504, doi : 10.1029/2011WR010911
  16. Gudmundsson, L., et al. (2012), Comparing large-scale hydrological model simulations to observed runoff percentiles in Europe, J. Hydrometeorol., 13(2), 604–620, doi : 10.1175/JHM-D-11-083.1
  17. Schellekens, J., Dutra, E., Martínez-de la Torre, A., Balsamo, G., van Dijk, A., Sperna Weiland, F., Minvielle, M., Calvet, J.-C., Decharme, B., Eisner, S., Fink, G., Flörke, M., Peßenteiner, S., van Beek, R., Polcher, J., Beck, H., Orth, R., Calton, B., Burke, S., Dorigo, W., and Weedon, G. P. (2017): A global water resources ensemble of hydrological models: the eartH2Observe Tier-1 dataset, Earth Syst. Sci. Data, 9, 389–413, doi : 10.5194/essd-9-389-2017.
  18. Zaherpour, J., Gosling, S. N., Mount, N., Müller Schmied, H., Veldkamp, T. I. E., Dankers, R., Eisner, S., Gerten, D., Gudmundsson, L., Haddeland, I., Hanasaki, N., Kim, H., Leng, G., Liu, J., Masaki, Y., Oki, T., Pokhrel, Y., Satoh, Y., Schewe, J., Wada, Y. (2018): Worldwide evaluation of mean and extreme runoff from six global-scale hydrological models that account for human impacts. Environmental Research Letters 13, 065015, doi : 10.1088/1748-9326/aac547
  19. Veldkamp, T. I. E., Zhao, F., Ward, P. J., de Moel, H., Aerts, J. C. J. H., Müller Schmied, H., Portmann, F. T., Masaki, Y., Pokhrel, Y., Liu, X., Satoh, Y., Gerten, D., Gosling, S. N., Zaherpour, J., Wada, Y. (2018): Human impact parameterizations in global hydrological models improve estimates of monthly discharges and hydrological extremes: a multi-model validation study. Environmental Research Letters 13, 055008, doi : 10.1088/1748-9326/aab96f
  20. Krysanova, V., Zaherpour, J., Didovets, I., Gosling, S.N., Gerten, D., Hanasaki, N., Müller Schmied, H., Pokhrel, Y., Satoh, Y., Tang, Q., Wada, Y. (2020): How evaluation of global hydrological models can help to improve credibility of river discharge projections under climate change. Climatic Change 163, 1353-1377, doi : 10.1077/s10584-020-02840-0
  21. Scanlon, B. R., Zhang, Z., Save, H., Sun, A. Y., Müller Schmied, H., van Beek, L. P. H., Wiese, D. N., Wada, Y., Long, D., Reedy, R. C., Longuevergne, L., Döll, P., Bierkens, M. F. P. (2018): Global models underestimate large decadal declining and rising water storage trends relative to GRACE satellite data. Proceedings of the National Academy of Sciences of the United States of America 115, 6, E1080-E1089, doi : 10.1073/pnas.1704665115
  22. Scanlon, B. R., Zhang, Z., Rateb, A., Sun, A., Wiese, D., Save, H., Beaudoing, H., Lo, M. H., Müller Schmied, H., Döll, P., van Beek, R. Swenson, S., Lawrence, D., Croteau, M., Reedy, R. C. (2019): Tracking seasonal fluctuations in land water storage using global models and GRACE satellites. Geophysical Research Letters 46 (10), 5254-5264, doi : 10.1029/2018GL081836
  23. Rateb, A., Scanlon, B.R., Pool, D.R., Sun, A., Zhang, Z., Chen, J., Clark, B., Faunt, C.C., Haugh, C.J., Hill, M., Hobza, C., McGuire, V.L., Reitz, M., Müller Schmied, H., Sutanudjaja, E.H., Swenson, S., Wiese, D., Xia, Y., Zell W. (2020): Comparison of groundwater storage changes from GRACE satellites with monitoring and modeling of major U.S. aquifers. Water Resources Research 56 (12), e2020WR027556, doi : 10.1029/2020WR027559
  24. Portmann, F. T. (2017): Global irrigation in the 20th century: extension of the WaterGAP Global Irrigation Model (GIM) with the spatially explicit Historical Irrigation Data set (HID), Frankfurt Hydrology Paper, 18, 131 pp.
  25. Siebert, S., Kummu, M., Porkka, M., Döll, P., Ramankutty, N., Scanlon, B.R. (2015): A global dataset of the extent of irrigated land from 1900 to 2005. Hydrol. Earth Syst. Sci., 19, 1521-1545. doi : 10.5194/hess-19-1521-2015
  26. Müller Schmied, H., Adam, L., Eisner, S., Fink, G., Flörke, M., Kim, H., Oki, T., Portmann, F. T., Reinecke, R., Riedel, C., Song, Q., Zhang, J., and Döll, P. (2016): Impact of climate forcing uncertainty and human water use on global and continental water balance components. Proc. IAHS, 374, 53-62. doi:10.5194/piahs-374-53-2016
  27. Döll, P. (2009): Vulnerability to the impact of climate change on renewable groundwater resources: a global-scale assessment. Environ. Res. Lett., 4, 036006 (12pp). doi : 10.1088/1748-9326/4/3/035006
  28. Portmann, F.T., Döll, P., Eisner, S., Flörke, M. (2013): Impact of climate change on renewable groundwater resources: assessing the benefits of avoided greenhouse gas emissions using selected CMIP5 climate projections. Environ. Res. Lett. 8, 024023. doi : 10.1088/1748-9326/8/2/024023
  29. Reinecke, R., Müller Schmied, H., Trautmann, T., Andersen, L. S., Burek, P., Flörke, M., Gosling, S. N., Grillakis, M., Hanasaki, N., Koutroulis, A., Pokhrel, Y., Thiery, W., Wada, Y., Satoh, Y., Döll, P. (2021): Uncertainty of simulated groundwater recharge at different global warming levels: a global-scale multi-model ensemble study. Hydrol. Earth Syst. Sci., 25, 787–810. doi : 10.5194/hess-25-787-2021
  30. 1 2 Döll, P., Trautmann, T., Göllner, M., Müller Schmied, H. (2020): A global-scale analysis of water storage dynamics of inland wetlands: Quantifying the impacts of human water use and man-made reservoirs as well as the unavoidable and avoidable impacts of climate change. Ecohydrology, 13, e2175. doi : 10.1002/eco.2175
  31. Döll, P., Zhang, J. (2010): Impact of climate change on freshwater ecosystems: a global-scale analysis of ecologically relevant river flow alterations. Hydrol. Earth Syst. Sci., 14, 783-799.
  32. Döll, P., Müller Schmied, H. (2012): How is the impact of climate change on river flow regimes related to the impact on mean annual runoff? A global-scale analysis. Environ. Res. Lett., 7 (1), 014037 (11 pp). doi : 10.1088/1748-9326/7/1/014037
  33. Eisner, S., Flörke, M., Chamorro, A., Daggupati, P., Donnelly, C., Huang, J., Hundecha, Y., Koch, H., Kalugin, A., Krylenko, I., Mishra, V., Piniewski, M., Samaniego, L., Seidou, O., Wallner, M., Krysanova, V. (2017): An ensemble analysis of climate change impacts on stream flow seasonality across 11 large river basins. Climatic Change, doi : 10.1007/s10584-016-1844-5
  34. Döll, P., Trautmann, T., Gerten, D., Müller Schmied, H., Ostberg, S., Saaed, F., Schleussner, C.-F. (2018): Risks for the global freshwater system at 1.5 °C and 2 °C global warming. Environ. Res. Lett., 13, 044038. doi : 10.1088/1748-9326/aab7
  35. Döll, P. (2002): Impact of climate change and variability on irrigation requirements: a global perspective. Climatic Change, 54(3), 269-293
  36. Döll, P., Müller Schmied, H., Schuh, C., Portmann, F., Eicker, A. (2014): Global-scale assessment of groundwater depletion and related groundwater abstractions: Combining hydrological modeling with information from well observations and GRACE satellites. Water Resour. Res., 50, 5698–5720, doi : 10.1002/2014WR015595
  37. 1 2 Herbert, C., Döll, P. (2019): Global assessment of current and future groundwater stress with a focus on transboundary aquifers. Water Resour. Res., 55, 4760-4784. doi : 10.1029/2018WR023321
  38. Schmidt, R., Schwintzer, P., Flechtner, F., Reigber, Ch., Güntner, A., Döll, P., Ramillien, G., Cazenave, A., Petrovic, S., Jochmann, H., Wünsch, J. (2006): GRACE observations of changes in continental water storage. Global and Planetary Change, 50, 112-126.
  39. Kusche, J., et al. (2009): Decorrelated GRACE time-variable gravity solutions by GFZ, and their validation using a hydrological model. J Geod, 83, 903-913
  40. Cáceres, D., Marzeion, B., Malles, J.H., Gutknecht, B., Müller Schmied, H., Döll, P. (2020): Assessing global water mass transfers from continents to oceans over the period 1948–2016. Hydrol. Earth Syst. Sci., 24, 4831-4851. doi : 10.5194/hess-24-4831-2020
  41. Horwath, M., Gutknecht, B. D., Cazenave, A., Palanisamy, H. K., Marti, F., Marzeion, B., Paul, F., Le Bris, R., Hogg, A. E., Otosaka, I., Shepherd, A., Döll, P., Cáceres, D., Müller Schmied, H., Johannessen, J. A., Nilsen, J. E. Ø., Raj, R. P., Forsberg, R., Sandberg Sørensen, L., Barletta, V. R., Simonsen, S. B., Knudsen, P., Andersen, O. B., Ranndal, H., Rose, S. K., Merchant, C. J., Macintosh, C. R., von Schuckmann, K., Novotny, K., Groh, A., Restano, M., Benveniste, J. (2022): Global sea-level budget and ocean-mass budget, with a focus on advanced data products and uncertainty characterisation, Earth System Science Data, 14, 411-447, doi : 10.5194/essd-14-411-2022
  42. Boulay, A. Bare, J., de Camillis, C., Döll, P., Gassert, F., Gerten, D., Humbert, S., Inaba, A., Itsubo, N., Lemoine, Y., Margni, M., Motoshita, M., Núñez, M., Pastor, A.V., Ridoutt, B., Schnecker, U., Shirakawa, N., Vionnet, S., Worbe, S., Yoshikawa, S., Pfister, S. (2015): Consensus building on the development of a stress-based indicator for LCA-based impact assessment of water consumption: outcome of the expert workshops. Int J Life Cycle Assess. doi : 10.1007/s11367-015-0869-8