Abstract

This report, prepared by the Climate Change Technical Subcommittee of the central Puget Sound (WA) Regional Water Supply Planning Process,provides guidance on approaches to including climate change in evaluations of water demand and water supply. The suggested approach uses well-accepted GCM outputs, transforms these outputs to reflect regional characteristics, and generates streamflows with this climate impacted meteorology for a range of climate change scenarios. Recommendations are provided for how to use the data created by the Committee to evaluate impacts to municipal water demand and supply, as well as other water resources and ecosystem issues. Other recommendations include clearly identifying the user’s needs for climate impacted data, keeping the evaluation appropriately simple, framing the problem in familiar terms, and emphasizing relative uncertainties