Balancing the Triple Bottom Line in Water Supply Planning for Utilities

Abstract

To achieve the triple bottom line (TBL) of sustainability, total water management efforts must analyze alternatives to address the potentially conflicting goals of economics (financial), environmental, and social issues. Traditionally, decisions were heavily influenced by economics. The alternative with the best cost-benefit ratio was generally considered to be superior. As the need to make sustainable decisions becomes increasingly important, a similar need surfaces for a methodology to balance sustainability objectives in a realistic manner. Goal programming is a technique that uses optimization methods to provide a means to solve a problem by striving towards multiple objectives simultaneously. This research applies an optimization framework to the integrated water supply planning process. The research demonstrates a methodology that can successfully generate a feasible set of alternative solutions while balancing all three goals of the TBL. Furthermore, the research showed that the goal programming methodology could use existing data (utility master plans) and widely available tools (Excel) to execute the model and develop trade-offs between the various aspects of the TBL. Demonstration data from a California utility’s publicly available water supply master plan were used to define the trade-offs between the relative costs for enhanced environmental and social goal achievement. The methodology explicitly details the societal and environmental values for each water management alternative, including desalination, dam, water rights exchanges, and drilling of new wells. The decision analysis of water supply strategies is enhanced through the incorporation of environmental and social sustainability in a balanced manner.