Incorporating Climate Change into Hydrological Data for Planning Models

The current approach to study the effect of climate change in water resources planning considers determining and using signals of climate change that are based on the results of historical and projected general circulation modeling. These signals are computed for a predefined time step, such as a month, by using streamflow data that is based on model output for selected historical and projected climatological periods, such as 30 years. These signals are used to perturb historical hydrological data to obtain the hydrological data that incorporates climate change, which is then used for planning studies. This approach allows for the analysis of various assumed emission pathways and general circulation model results independently of one another. The approach generally shows the possibilities based on model results. Uncertainties surrounding emission pathways and general circulation modeling necessitate going beyond the possibilities to the study of the likelihood of climate change scenarios. This paper describes and discusses the current approach used to incorporate climate change in water resources planning, shows its limitations, and suggests possible approaches for future improvement.