Trend detection in the water regime of the main rivers of the Province of Mendoza, Argentina

Abstract

Hydrologic systems are potentially sensitive to climate change. The objective of this paper is to detect possible changes in the runoff regime of mountain rivers in the Province of Mendoza, Argentina. The methodology is based on parametric (Student’s t-test) and non-parametric (Mann-Kendall) statistical tests applied to time series of monthly, maximum and minimum flows, and of typical daily flows derived from the flow duration curve. Both tests yielded similar results for a 5% significance level. No trend was detected in monthly, annual, maximum, minimum and typical flow series on the Diamante River at La Jaula and the Grande River at La Gotera. Trends rose with late spring and summer flows in the Mendoza River at Guido. In the Atuel River, at La Angostura, flow trends increased in all months, with the exception of the December through February period. The annual flow of the Tupungato and Mendoza at Guido, the daily minimum of Vacas and Atuel at La Angostura, and the drought flow of Vacas, Tunuyan and Atuel have significantly increasing trends. Puente Sosneado on the Atuel is the only one with negative trends in the flow series corresponding to the February–April period, and to annual and typical flows exceeded 90, 180, 270 and 355 days a year. In summary, of the 210 time series analyzed, only 40 exhibit changes and most of them are associated with low-water periods.