Determination of probabilities for the generation of high-discharge flows in the middle basin of Elqui River, Chile

SANTIBAÑEZ OSSA, FERNANDA A.; MOREIRAS, STELLA M.; ARANEO, DIEGO; VERGARA DAL PONT, IVÁN P.; FERRANDO ACUÑA, FRANCISCO J.; SANTIBAÑEZ OSSA, FERNANDA A.; MOREIRAS, STELLA M.; ARANEO, DIEGO; VERGARA DAL PONT, IVÁN P.; FERRANDO ACUÑA, FRANCISCO J.

NATURAL HAZARDS (DORDRECHT)

SPRINGER

Lugar: Berlin; Año: 2018 vol. 93 p. 531 - 546

0921-030X

The probabilities for the generation of hyperconcentrated flows, and debris and mud flows in the middle basin of Elqui River (Chile) are determined. The objective was achieved collecting for a period of 14 years, the precipitation events generating high-discharge flows, as well as the larger precipitation events that did not generate this process. For each of these events, data of peak 1-h storm precipitation, temperature (representing the zero-isotherm altitude) and antecedent precipitation of 1, 5 and 10 days, were collected from three meteorological stations. Initially an ordinal logistic regression model for each antecedent precipitation was fitted, but all were discarded due to the low significance of this variable. Subsequently a new model with the remaining variables was performed, which was statistically validated and presented an efficiency of 90 % in the prediction of flows. From the final model, it was considered prudent to define the probability of 50 % both for the threshold of hyperconcentrated flows and for the debris and mud flows. In turn, the partial correlation coefficients of each predictor variable with respect to the dependent, were calculated, establishing that the temperature has greater influence than the peak 1-h storm precipitation.