Regionalization of low flows in southwest Germany

The hydrogeological conditions of a region strongly influence the low flow behaviour of river systems. The quantification of the hydrogeological conditions of a catchment and the application of hydrogeology for estimation purposes is very difficult. Up till now only a few solutions are found in the literature. This paper discusses a river network approach using hydrogeological conditions to estimate mean annual ten-day minima of discharge. The new method allows one to estimate flow parameters not only at a single site in a river stretch but also in space. The method has been tested on a data set in southwest Germany. The results showed a good agreement between the estimated discharges and the empirical data. The new method is therefore considered to be a useful tool, in particular for water management problems.