Paired Catchment Analysis of the Impact of Human Activities on Hydrological Drought around the World
Abstract
Drought is an important natural hazard with a projected increase in frequency and severity worldwide. The intertwined hydrological and social processes related to drought have only recently started to be studied. Hydrological droughts do not only have natural causes; anthropogenic activities can also alleviate, enhance or cause droughts. Therefore we need to develop the tools to analyse, quantify and understand the human impact on droughts worldwide and help improve water management approaches. Here, we apply a paired-catchment method to quantify human impact on streamflow drought and compare with scenario modelling. Taken from flood research, the paired catchment approach compares undisturbed and disturbed catchments or sub-catchments (e.g. upstream-downstream comparison). Scenario modelling is used to check the method and validate results. This work has been done on a number of different catchments and human activities across the world. An upstream-downstream approach has been taken for an arid basin in Chile, quantifying the impact of a dam. Results showed that the dam helps to alleviate against small drought events, however it cannot help against large multi-year drought events. The comparison of droughts in a scenario with dam and a naturalised scenario gives similar results. Paired catchment analysis of the effect of groundwater (GW) abstraction in the UK showed fewer, but longer and more severe hydrological droughts in the disturbed catchment; in many cases to twice that of the natural catchment. Again, scenario modelling confirmed this difference. Paired catchment analysis of the effect of GW abstraction in Australia showed more variable results than in the UK, but during the Millennium Drought the disturbed catchment had years of near zero flow, whereas the undisturbed catchment continued flowing. Further case studies in the UK showed the impact of land-use change (urbanization) on drought, but not to the same magnitude as that of GW abstraction. We demonstrate here that a paired-catchment analysis is a good tool for improved understanding of human modifications to natural drought processes. This helps to make the step towards increased knowledge of the hydrosocial cycle, especially with regards to understanding the interlinked situation between human activities and water availability.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.H51M..02R
- Keywords:
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- 1630 Impacts of global change;
- GLOBAL CHANGEDE: 1803 Anthropogenic effects;
- HYDROLOGYDE: 1807 Climate impacts;
- HYDROLOGYDE: 1834 Human impacts;
- HYDROLOGY