Nazas RiVer BasIn

Researches 

1. ARID LANDS EXPANTION UNDER CLIMATE CHANGE SCENARIOS AND TWO FUTURE TIME HORIZONS. NAZAS RIVER BASIN CASE

Abstract.-  Nazas River Basin (NRB) is an arid basin of great importance for localities that depend on it. However, studies of possible effects of Climate Change (CC) in this area are scarce. Our aims were to evaluate the possible impact of CC on the extent and distribution of aridity by comparing four models, two shared socioeconomic pathways and two-time horizons; and to compare changes in land use and vegetation cover in areas possibly affected by aridity. CC models and historical data used were downloaded from WorldClim and CONABIO. Aridity was estimated using the De Martonne aridity index (DMAI). To analyse possible changes, we carried out the process suggested by IPCC to evaluate changes in land use and vegetation cover. Historical data shows that NRB's surface is 64% arid. Only CNRM-CM6-1 model shows significant changes. With a radiative forcing of 8.5 W m-2, the aridity of the basin could increase up to 81%, affecting 29% of the territory. In this area, transformation from forest to productive lands was observed. This could have an impact on carbon sequestration and increase CC impacts. Due to the complexity of NRB, more comprehensive studies are required to achieve a better understanding of the repercussions of CC.

Keywords: Map analysis, De Martonne’s aridity index, Land Use and Vegetation Cover, Shared Socioeconomic Pathway, Radiative Forcings.

NRB is an endorheic hydraulic system in an area of 48,790 km2. The Ramos and Sextín rivers originate in the mountain range known as 'Sierra Madre Occidental'. Its flows descend to the Lázaro Cárdenas dam (Trucios-Caciano et al., 2009) located (25.587ºN & 105.042°W) around 1650 meters above sea level (masl). The Nazas River derives from the Lázaro Cárdenas dam, the longest river in the State of Durango and one of the most important in northern Mexico (SRNMA-DGO, 2012). This extends for approximately 600 km to the region known as CL at 1100 masl .