Abstract
Quantifying the influence of human activities, such as reservoir building, water abstraction, and land use change, on hydrology is crucial for sustainable future water management, especially during drought. Model-based methods are very time-consuming to set up and require a good understanding of human processes and time series of water abstraction, land use change, and water infrastructure and management, which often are not available. Therefore, observation-based methods are being developed that give an indication of the direction and magnitude of the human influence on hydrological drought based on limited data. We suggest adding to those methods a "paired-catchment" approach, based on the classic hydrology approach that was developed in the 1920s for assessing the impact of land cover treatment on water quantity and quality. When applying the paired-catchment approach to long-term pre-existing human influences trying to detect an influence on extreme events such as droughts, a good catchment selection is crucial. The disturbed catchment needs to be paired with a catchment that is similar in all aspects except for the human activity under study, in that way isolating the effect of that specific activity. In this paper, we present a framework for selecting suitable paired catchments for the study of the human influence on hydrological drought. Essential elements in this framework are the availability of qualitative information on the human activity under study (type, timing, and magnitude), and the similarity of climate, geology, and other human influences between the catchments. We show the application of the framework on two contrasting case studies, one impacted by groundwater abstraction and one with a water transfer from another region. Applying the paired-catchment approach showed how the groundwater abstraction aggravated streamflow drought by more than 200% for some metrics (total drought duration and total drought deficit) and the water transfer alleviated droughts with 25% to 80%, dependent on the metric. Benefits of the paired-catchment approach are that climate variability between pre-and post-disturbance periods does not have to be considered as the same time periods are used for analysis, and that it avoids assumptions considered when partly or fully relying on simulation modelling. Limitations of the approach are that finding a suitable catchment pair can be very challenging, often no pre-disturbance records are available to establish the natural difference between the catchments, and long time series of hydrological data are needed to robustly detect the effect of the human activities on hydrological drought. We suggest that the approach can be used for a first estimate of the human influence on hydrological drought, to steer campaigns to collect more data, and to complement and improve other existing methods (e.g. model-based or large-sample approaches).
Original language | English |
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Pages (from-to) | 1725-1739 |
Number of pages | 15 |
Journal | Hydrology and Earth System Sciences |
Volume | 23 |
Issue number | 3 |
DOIs | |
Publication status | Published - 26 Mar 2019 |
Externally published | Yes |
Funding
Acknowledgements. Anne F. Van Loon and Sally Rangecroft were supported by Rubicon NWO grant “Adding the human dimension to drought” (reference number: 2004/08338/ALW). Gemma Coxon was supported by NERC MaRIUS: Managing the Risks, Impacts and Uncertainties of droughts and water Scarcity, grant number NE/L010399/1. We thank Wouter Coomans (Wageningen University) for collating and analysing the Australian data. The research also contributed to the European Union-funded H2020 project ANYWHERE (contract no. 700099). It is part of the IAHS Panta Rhei Drought in the Anthropocene working group and it supports the work of the UNESCO-IHP VIII FRIEND-Water programme and the programme of the Wageningen Institute for Environment and Climate Research (WIMEK-SENSE). The drought analysis R code is available upon request. We thank the editor, Markus Hrachowitz, and the reviewers Jamie Hannaford, Sivara-jah Mylevaganam, and two anonymous reviewers for their comments and suggestions, which greatly improved this paper.
Funders | Funder number |
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Horizon 2020 Framework Programme | 700099 |
Natural Environment Research Council | NE/L010364/1 |
National Eye Research Centre | NE/L010399/1 |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek | 2004/08338/ALW |