This project officially began on April 1, 1995. We are compiling the analysis data sets and selectively testing some individual data series using exploratory data analysis techniques. Understanding the linkages between interannual changes, such as those associated with ENSO and decadal-scale patterns, is an important goal of this project and will be a continuing key objective. Additional analyses of the nature and significance of inter-series coherence at interannual to centennial time scales will be performed. Widespread droughts are evident in the 1930s and 1950s, as well as droughts near the turn of this century and in the recent past.
Units are in percent.
Note that the decline since about 1950 is also found in streams with minimal human impact. The influence of North Pacific atmospheric circulation on streamflow in the West. Historical and Paleoclimatic Aspects of the Southern Oscillation , Cambridge University Press, pp. The influence of precipitation and temperature on seasonal streamflow in California. Drought frequency in central California since 101 B.C. recorded in giant sequoia tree rings.