Flood flow prediction in torrential watersheds of the French Pyrénées range: the ANETO approach

Abstract

Flood flow estimations in torrential watersheds suffer from numerous uncertainties. In order to guide practitioners to predict realistic orders of magnitude of these flows, a method based on statistical regression and geographic analysis (ANETO, acronym for Approche naturaliste et statistique pour l'estimation des débits de crue des bassins versants torrentiels pyrénéens) was designed by the Restoration of Mountainous Territories (RTM) department of the National Forest Office (ONF). ANETO is part of a process of updating and regionalisation of methods based on multiple regression analysis published by the Technical Centre for Rural Engineering and Forestry (abbreviated CTGREF in French) in the early 1980s. In addition to these initial objectives, a significant improvement in the performance of these approaches has been made possible by introducing into the analysis process the consideration of factors related to the climatological environment and the geomorphology of catchment areas. The field for application of the method corresponds to watersheds of the French Pyrenees, ranging from 4 to 500 km² in area. It takes into account classical hydrological parameters, and integrates climatic and geomorphologic characteristics, which significantly increase the performance of the model.