Annual and monthly runoff analysis in the Elqui River, Chile, a semi-arid snow-glacier fed basin

Resumen

Balocchi, F., Pizarro, R., Meixner, T., & Urbina, F. (November-   December, 2017). Annual and monthly runoff analysis in   the Elqui River, Chile, a semi-arid snow-glacier fed basin.   Water Technology and Sciences (in Spanish), 8(6), 23-35,

DOI:   10.24850/j-tyca-2017-06-02.  

Climate change and its relationship to temperature are   critical factors affecting glaciers, especially when populations   depend on these ice reservoirs. The use of the precipitationrunoff   coefficient in semi-arid, mountainous regions that   are fed by glaciers can lead to important findings about   how glacial melt responds to climate change. This study   analyzed 40 years of monthly and annual precipitation   and runoff data (1970-2009) from four sub-basins of the   Elqui River (29° 27’- 30° 34’ S and 71° 22’- 69° 52’ W), in   the Coquimbo region of Chile. The Elqui basin has a rainsnow-   glacial melt regime. The areal average rainfall was   estimated using the Thiessen polygon method. Gumbel   and Goodrich probability distribution functions and the   Log-Normal Probability Density Function (PDF) were used   to understand the temporal behavior of precipitation and   streamflow. The data-time behavior and PP Q-1 coefficients   were also analyzed. And the Mann-Kendall (MK) test was   used to compare the results. No trends were found for flow,   while a negative trend in rainfall was identified. The summer   flows were notable, which remained constant. In spite of the   differences between the PP Q-1 coefficient and the MK test,   the flow clearly does not come from rainfall but rather from   glacial melt.