ASSESSING CLIMATE-CHANGE IMPLICATIONS FOR WATER-RESOURCES PLANNING

Numerous recent studies have shown that existing water supply systems are sensitive to climate change. One apparent implication is that wate r resources planning methods should be modified accordingly. Few of th ese studies, however, have attempted to account for either the chain o f uncertainty in projecting water resources system vulnerability to cl imate change, or the adaptability of system operation resulting from e xisting planning strategies. Major uncertainties in water resources cl imate change assessments lie in a) climate modeling skill; b) errors i n regional downscaling of climate model predictions; and c) uncertaint ies in future water demands. A simulation study was designed to provid e insight into some aspects of these uncertainties. Specifically, the question that is addressed is whether a different decision would be ma de in a reservoir reallocation decision if knowledge about future clim ate were incorporated (i.e., would planning based on climate change in formation be justified?). The case study is possible reallocation of f lood storage to conservation (municipal water supply) on the Green Riv er, WA. We conclude that, for the case study, reservoir reallocation d ecisions and system performance would not differ significantly if clim ate change information were incorporated in the planning process.