Some general aspects of fluctuations of annual runoff in the upper Colorado River basin

Abstract

The fluctuations of annual river flows and derived effective annual precipitations (defined as precipitation minus evapotranspiration on an area) of the Upper Colorado River Basin are subjects of this study. The data for this study are composed of annual flows for 14 river stations in the Upper Colorado River Basin and around it, and of the annual flows of the key station of the Upper Colorado River, at Lee Ferry, Arizona. Three statistical techniques were used: 1) distribution of the first serial correlation coefficient; 2) correlogram analysis; and 3) distribution of range. The series of annual flows and series of derived effective annual precipitations were compared with the same statistical characteristics of random time series. The comparison of these statistical parameters shows that the fluctuations of effective annual precipitations on river basins are very close to the fluctuations of random series. Probability characteristics of random variables may be applied to annual river flows of the Upper Colorado River, provided due corrections are made for the effect of water carryover from year to year, and for non-homogeneity in data. A discussion of hydrological characteristics of annual runoff in the Upper Colorado River Basin is given, with general conclusions of this study and some recommendations for further studies.