To understand river channel changes and fluvial activity it is necessary to know the magnitude, frequency, and sequence of flows and the controls upon them and compare the channel responses in periods with known conditions. This paper identifies the characteristics of mean and maximum flows of the Gila River in southeast Arizona in the twentieth century and examines their relationship to precipitation, to the Palmer Hydrological Index, and to land and water management. Flow records show very high total flows in the period 1905-1916 and very low flows in the 1940s and 1950s. Eleven of the 20 highest annual peaks since 1914 have occurred since 1965. The 1983 flood was nearly comparable with the flood of 1905, which is associated with the destabilization of the Gila River. Increased flooding is found to be associated primarily with increased winter precipitation and the evidence available indicates that water usage and land management have much less influence on flows than has climate. Major variations, on the scale of a few decades, are similar to those identified in Australia, which have had profound effects on river channels. Widespread recognition of the magnitude and persistence of the flow variations has important implications for water resources and flood management.
|Number of pages||20|
|Publication status||Published - 1994|