A Risk-Based Methodology For Fresh Water Management: Managing Saline And Freshwater Interaction In The Rhine-Meuse Estuary In The Netherlands.

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Saskia van Vuren, Marit Zethof

Friday 3 july 2015

9:45 - 10:00h at Oceania (level 0)

Themes: (T) Managing deltas, (ST) Saline and freshwater interaction

Parallel session: 14K. Managing deltas - Impacts

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In recent times it has been observed that delta regions world-wide encounter problems resulting from fresh water scarcity and corresponding deficits. It may bring along negative consequences for various sectors, viz. agriculture, transport, industrial and energy, and may also induce problems for other societal interests such as nature, drinking water supply and public health. Future climate change and socio-economic developments make delta societies even more susceptible to water scarcity arising from drought events. Drought-risks exhibit a wide range of uncertainty, making water resource management decisions even more difficult than they already are. As a result, making decisions regarding fresh water assignment is becoming increasingly more complex. Consequently, there is a strong wish to make uncertainty and risks involved in fresh water management practice more explicit. We therefore developed of a risk-based methodology to support fresh water management enabling an assessment of drought-related risks by considering jointly the probability of drought-related hazard events and the consequences of these hazard events. The new methodology takes into account uncertainty resulting from inherent uncertain conditions, such as: (1) fresh water supply from river basins, salt water intrusion and fresh water storages in soil and in the surface water system, and (2) water needs of end users/sectors. Identifying and quantifying these uncertainties is necessary to understand the possible favourable or adverse aspects of present fresh-water assignment regulations, alternatives and other measures to prevent water scarcity and mitigate drought-damages. The development of a risk-based methodology will enable a modernization/or: renewal of paradigms in risk management, where decision-making under uncertainty and managing trans-sectorial and cross-regional risks are becoming common practice. The potential of the risk-based methodology is demonstrated for the Rhine-Meuse Estuary in the Netherlands where water deficits frequently occur due to the joint occurrence of low river discharges and severe salt water intrusion.