Climate Change in Water Utility Planning: Decision Analytic Approaches
There is strong evidence that climate change consistent with greenhouse-gas-induced warming is already occurring and that it is affecting hydrologic processes in many parts of the world. These changes are expected to accelerate with the continuing accumulation of carbon dioxide and other greenhouse gases in the atmosphere. These facts, coupled with the typically long lead times in water resource planning suggest that it is not too early to begin considering the potential effects of climate change when developing long-run resource management strategies and plans for infrastructure investment.
In August of 2007, the project held a 2-day workshop at the National Center for Atmospheric Research (NCAR). The workshop focused on articulating project goals and methodologies, documenting the status of the collaborative projects, and exploring opportunities for synergy in the research efforts of the participating utilities. Three dozen participants attended the workshop, and all participants actively engaged in the discussion of research methods, problems to be addressed, and collaborative roles of the participating utilities and the NCAR research team.
Each of the participating utilities presented a status report on their planned work. In addition, other talks focused on downscaled climate scenarios for local-scale hydrologic assessments, potential water quality impacts and decision analytic methods, including an example of actual application of such an approach. A key conclusion of that workshop was that this project, 3132, should produce a Climate Change “Cookbook” (i.e., a generic list of ingredients and instructions on how to combine them) that would help guide water utilities to incorporate climate change into their strategic and long-term planning process. While this report may be only a beginner’s “cookbook,” it is intended to provide useful guidance to other water utilities by describing the structured process and the case study results.
One observation regarding the case studies is that while they applied some of the same approaches and used some of the same models, datasets and assumptions, the nature and “flavor” of the results are quite different. This is partly an outcome of the unique circumstances of each utility, and partly due to the available information, personal expertise, and problems currently experienced by those working on their own case studies. A general lesson that can be drawn from this project is that to be most useful, a climate change assessment must be tailored to the specific circumstances and information needs of the utility involved.