Development of Decision Support Tools for Water Energy Food Infrastructure Management of Sri Lanka

Abstract

The energy and food sectors of the economy heavily rely on water resources. All nations face challenges of meeting increasing demand for water, food, and energy due to limited and uncertain resources, complex multisector relationships, and difficulty in managing stakeholder participation in infrastructure planning and management. This dissertation research used systematic mathematical modelling approaches for evaluating infrastructure plans for supplying water and energy under constraints imposed by multiple interdependent objectives. Using Sri Lanka as a case study, the impacts of climate variability and the availability of water resources on the operation of and expansion planning for water-energy infrastructure are explored. The research included analyses of the relationship of indices of large-scale climate patterns such as the El Nino-Southern Oscillation (ENSO) to rainfall that supplies the major reservoirs, development of a system dynamics model of the complex reservoir cascade system in the Mahaweli River basin, determination of reservoir operating rules to optimize multiple objectives, and the use of decision analysis tools to incorporate stakeholder valuation of economic, social, and environmental goals into the reservoir cascade and power generation expansion planning context. Major findings from the research include the following. (1) The statistical correlation of dry-season rainfall to climate signals (e.g., ENSO) suggest that season ahead forecasts of drought probability may be useful for planning water and energy adaptation measures. (2) Operation policies that increase the reliability and resilience of a reservoir cascade can be selected through use of a system dynamics model. (3) Decisions about how agricultural yield and hydropower generation can be balanced can be informed by the trade-off frontier generated using multiobjective optimization. (4) Although various stakeholders value different aspects of alternate plans for expansion of infrastructure differently, results from multicriteria decision analysis show that alternatives that have at least moderate support from all stakeholders can be identified. (5) Integrating power generation expansion optimization methods and multicriteria decision analysis methods inform stakeholder decisions considering trade-offs between multiple objectives of alternative plans. Decision support tools based on integrated modelling capabilities are essential to inform the strategies for addressing the increasing demands of water and energy infrastructure for using variable resources for every nation. The Sri Lanka case study reported in this dissertation provides a base for such future works.