Author(s): Carlos Escalante-Sandoval; Lilia Reyes-Chavez
Linked Author(s):
Keywords: Water availability; Trend tests; Meteorological drought properties; Synthetic generation; Annual rainfall frequency analysis
Abstract: Mexico is a country which presents a great diversity of climatic and geographical conditions, as well as significant seasonal variation in rainfall, all of which have a great impact on the availability of water resources. The natural availability also varies greatly from the arid and semiarid regions in the north and northwest to the largely humid regions in the south and southeast. Drought is one of the most devastating natural phenomena and its presence reduce the volumes of water stored in dams and also diminish aquifer recharge, affecting agricultural, livestock, and industrial activities, as well as electric power generation, aside from the impact this has on the region’s flora and fauna. Mexico suffers a drought on average every four years with duration of two years. However, the extraordinary condition of this phenomenon is experienced on average every 14 years; such is the case of the years 1957, 1969, 1982, 1997 and 2011. In recent years, droughts in Mexico caused damages as high as $1. 5 billion dollar for the 2010-2012 three-year drought, and although it affected two-thirds of the national territory, the largest damages to crops and cattle occurred in the north states (Aguascalientes, Chihuahua, Coahuila, Durango, Nuevo Leon, Baja California, Sonora, Sinaloa and Zacatecas). The most important strategy for mitigating the effects of droughts consists of having contingency plans including preventive and mitigating actions. Knowledge of the volumes utilized by users, along with the availability of rainfall water, surface water and groundwater, should constitute the basis for making this resource more sustainable. The objective of this paper is to make a meteorological drought analysis and obtain the rainfall that should be used in Mexico for planning purposes. For this purpose, annual rainfall data for the 61 years (1950–2010) from 647 meteorological stations located in northern Mexico was used to study the properties of meteorological drought and to estimate rainfall events associated to different return periods by fitting the univariate and mixed distributions for the minima. Nonparametric tests are used to investigate the presence of abrupt and slowly varying changes. The 13% of the analyzed samples were considered nonstationaries and the most important changes were observed in the annual rainfall series located at state of Nuevo Leon, where 28% of its stations show significant trends. According to the results, in northern Mexico the available rainfall for purposes of irrigation should be only 62% of the annual average rainfall. This rainfall event is associated to 10-year return period, and takes in account the rainfall variability in deficit periods.
Year: 2013