Analysis of drought in the context of the 1944 International Water Treaty

Abstract

This study presents an analysis of drought in the basins of the Colorado and Bravo Rivers using the Streamflow Drought Index, SDI. For the Colorado River, three years of extreme drought (1934, 1977 and 2002) were recorded in the entire basin and its upper region, and four years (1928, 1929, 1935, and 1936) in the lower basin. Applying this same approach to the Bravo River, extreme drought was recorded for the K3 period (October-June) period during the agricultural year of 1901-1902. The Standardized Precipitation Index, SPI, was only applied in the Colorado River basin, where extreme drought was found in both the lower
and the entire basin for the years 1950, 1956 and 1989. In addition, extreme drought also occurred in the upper basin during the latter year. These results are important to joint water management by Mexico and the United States in both basins in order to meet the demands of their inhabitants, fulfilling the promises established in the 1944 International Water Treaty and taking the measures needed concerning the impact of climate change on the hydrological cycle in the region.