Flow regionalization. An approach to identify homogeneous regions

spatial variability of the flow conditions, which often exists in the watershed, needs a complementation of the methodologies to estimate the obtained information from punctual data to take into account its representatively. This leads to define zones where certain constancy of the hydrological characteristics is maintained. Nevertheless, in many cases it is not trivial to determine a criterion (or criteria) to establish these regions, The obtained results by application of multivariate statistical-mathematical methods (cluster and principal components analysis and Andrews' plots) to identify homogeneous regions are presented here. This approach is an alternative that considers both the multidimensional data analysis and their integrated evaluation with the system conceptual characterization. The application area comprises 11 basins in the northwest of Argentina, which have historical records of 605 floods. However, in this country zone, with an important drought where it is very important to do an efficient water resources management, only 3 of these basin are nowadays gauging. The homogeneous regions identification resulting has allowed to define strategies to the network measurement design which considers the representatively of the observations and their potentially to transfer information.