The alluvial history of Whitewater Draw, an arroyo in the Sulphur Springs Valley, southeastern Arizona, is characterized by numerous degradational and aggradational events. Shifts in climate appear to be responsible for the major changes in depositional environments recognized in Whitewater Draw over the past 15 000 yr. However, the degradation and aggradation documented during apparently stable climatic periods were primarily controlled by geomorphic parameters. Comparison between the alluvial records of arroyos in the adjacent upper San Pedro Valley and Whitewater Draw shows that periods of degradation and aggradation were out of phase in number, character, and timing. These differences indicate that the fluvial systems in the Sulphur Springs Valley and the San Pedro Valley responded differently to external climate shifts and that both systems were influenced by local geomorphic parameters. This demonstrates that regional correlation of late Quaternary deposits from one valley to the next should not be attempted without absolute temporal control and that intervalley correlations must take into consideration the complexity of fluvial processes.