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| Titel |
Human water consumption intensifies hydrological drought worldwide |
| VerfasserIn |
M. F. P. Bierkens, Y. Wada, D. Wisser, N. Wanders, L. P. H. Van Beek |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250064028
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| Zusammenfassung |
| Drought is a natural phenomenon caused by below-normal precipitation over a
prolonged period. Recent studies suggest an intensification of drought events over
substantial regions due to anthropogenic global warming. Over the past decades, human
water consumption has more than doubled, primarily due to a large increase in
irrigation, and substantially reduced streamflow over various regions. It can thus be
expected that upstream human water consumption intensifies hydrological drought in
many regions of the world. Yet, few studies have investigated this impact up to
now.
We use the global hydrological model PCR-GLOBWB to simulate surface freshwater
availability, i.e. water in rivers, lakes, reservoirs and wetlands, at a 0.5o spatial resolution for
the period 1960-2001. We also estimate human water consumption, i.e. water withdrawal
minus return flow, from agricultural, industrial and domestic sectors for the same period.
Since country statistics on consumptive water use rarely exist, we use available
socio-economic data to reconstruct past sectoral water consumption at a 0.5Ë grid. We then
perform two simulation runs in which the impact of upstream human water consumption on
downstream surface freshwater availability and resulting hydrological drought is assessed.
The first run evaluates streamflow under variable climate inputs and with human water
consumption set to the level of 1960. From this run, the Q80 is derived as the onset of
hydrological drought following the widely used variable threshold level method. The second
run is subject to the reconstructed water consumption over 1960-2001 and the ensuing
deficit volume calculated relative to the 1960 reference, which are indicative of the
intensification of hydrological drought and its implication for water supply. We standardize
deficit volumes to compare the severity of hydrological drought among different
catchments.
Results show that upstream human water consumption substantially alters downstream
water availability and intensifies the severity of hydrological drought worldwide. The severity
of hydrological drought increases by more than 50% due to reduced water availability
downstream, particularly in regions where surface water is heavily exploited (e.g., Indus,
Ganges, Krishna-Godavari, Huang He, Hai He, Colorado). In these regions, hydrological
drought has also become more frequent and persistent. Overall, the severity of hydrological
drought has been aggravated in many parts of the world as human water consumption is rising
rapidly in recent years. |
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