Regionalization based on geomorphological variables as a tool for calculating flood flow estimates. Application to the south-central zone of Chile

Abstract

Most of the time in engineering practice, flow estimates must be fast and accurate, seeking to optimize analysis time. From this problem arises the aim of this research, which consists of proposing a rapid and effective flood flow estimation methodology for different return periods. The methodological proposal is based on the hydrological regionalization method. The existence of three indices that manage to represent the response of the basin to flood flows is verified: the rain seasonality index, the seasonality index in the dry season and the flood magnitude index are verified, all being obtained from fluviometric records. It is established that the geomorphological variables Gravelius Compactness index, Average Height and Area of the basin are respectively related to these indices. The different statistical techniques applied are able to determine an adequate grouping of five homogeneous groups in the south-central zone of Chile (between south latitude 34º 50 ’and south latitude 39º 35’). A classification plan for basins without hydrological information and regional estimation equations for each of them is displayed. With this research it is expected that an important step will be taken to achieve the automation of the flood flow estimates in any type of basin through updated, easy, and understandable equations based, above all, on an adequate analysis of the hydrological behavior of the basins.