Use of regionalized stormflow coefficients with a view to hydroclimatological hazard mapping

An attempt was made to compensate for the lack of long hydrological time series and the lack of information on maximum streamflow, in the Alzette River basin (Luxembourg) via the regionalization of stormflow coefficients. Streamflow data recorded since 1995 with a very dense streamigauge network allowed the determination of maximum stormflow coefficients in 18 sub-basins of the Alzette. The stormflow coefficients were then regionalized via stepwise multiple regression analysis for 83 different sub-basins of the Alzette. Combined with 10-year daily rainfall heights (statistical estimation), this regionalization allowed the spatial variability of storm runoff in the Alzette basin to be mapped, thus providing a view of hazard and risk-producing areas, as well as of risk-exposed areas. In a basin with little historical hydrological information this technique can help identify areas where storm runoff reducing measures should be applied from the outset.