Decision support for long-term water resource management in semi-arid areas: Insights from South Africa

Abstract

Public goods, such as bulk water supply infrastructure, have proved vulnerable to failures in market and government allocation strategies. Common to both strategies are uncaptured costs and benefits. This implies a measurement problem due to shortcomings in quantification techniques for estimating costs and benefits for different market- and government-driven allocation strategies and led to decisions based on incomplete information. With legitimate decision-making depending on reliable information, the measurement problem poses an obstacle to social welfare maximisation. This paper incorporates components of economic valuation theory, multi-criteria decision analysis, a public survey and a modified Delphi expert panel technique to score the multi-criteria attributes and assign weights. The approach was applied in the Western Cape province of South Africa and specifically focused on a choice problem regarding different long-term bulk-water resource management options for the area. The decision-making context was broadened to accommodate unaccounted-for costs and benefits in water resource allocation decision-making. Both spatial and temporal dimensions of the decision-making context were expanded. The spatial expansion manifested in the physical expansion of the management area, which led to expansions in representation in the decision-making process. The temporal expansion manifested in the consideration of different sequences of bulk supply schemes over time instead of a selection of schemes at the same time. Two surveys were conducted to accommodate such expansions. The first focussed on public preferences towards long-term water allocation management and the second on inputs of members of an expert panel by means of a modified Delphi technique. Questions regarding whether, and if so, to what extent, the public needed to be accommodated in long-term water resource allocation decision-making came to the fore. A broad acceptability towards a willingness to pay for "greener" water was observed and the outcome may be used to motivate a paradigm shift among managers to consider, without fearing harm to their political positions, "greener" water supply options more seriously, even if such options imply higher direct costs.