I.  Background
Seasonal streamflow volumes in the Upper Klamath Basin, Oregon, USA are of great interest to water resource managers because seasonal water quantity is an important factor affecting the livelihood of fish, growers, tribes, and municipalities in the area.  Human effects on the flow regime in the areas downstream of Upper Klamath Lake are high, but they are small on the two primary tributaries that form approximately 50 percent of the total inflow into the lake, the Sprague and Williamson Rivers.  This permits an evaluation of climate variability affecting interannual streamflow volumes on these two rivers.  The knowledge established with this study permits the development of improved predictive streamflow models that are robust, and thus desirable, for the management of water related resources in the basin.