Watersheds in the western US are going to be subtly or extensively altered as climate change effects continue, depending on location and type of impact, the Bureau of Reclamation says in a report released April 25, 2011.
The report, mandated by Congress in 2009, focuses on seven watersheds that cover much of the region (Colorado, Columbia, Klamath, Missouri, Upper Rio Grande-Pecos, Sacramento-San Joaquin, and Truckee-Carson basins), and describes expected changes in factors such as temperature, precipitation, snowpack, and streamflow that affect urban water supplies, hydropower, flood control, irrigation, recreation, and wildlife habitat.
- "SECURE Water Act, Section 9503(c) — Reclamation, Climate Change and Water, Report to Congress 2011" ; press release. 
Major changes often are expected, with the magnitude varying substantially by location. The report’s data and information allow you to dig into the details to some degree for the watersheds of interest to your audience, though the overall projections sometimes don’t vary substantially within a watershed. However, details for representative stations within a watershed sometimes do differ quite a bit from each other, allowing you to at least cover those situations in better detail.
In some instances, projects designed to mitigate expected problems — such as revamping the elevation of a water intake to accommodate expected water level drops, or addressing anticipated increases in flooding — are already being developed. In other instances, little or nothing is being done, and funding and political and public will are minimal or nonexistent.
The report is based on existing data and numerous assumptions, both of which are worth investigating so you can tell your audience about the many uncertainties (often acknowledged in the text) underlying this report.