In 1996 Rijkswaterstaat RIZA (Institute for Inland Water Management and Waste Water Treatment) and KNMI (Royal Netherlands Meteorological Institute) started to work together on a new methodology to provide a better physical basis for the estimation of the design discharge of the main Dutch rivers. The first component of this new methodology is a stochastic multivariate weather generator, which generates long simultaneous records of daily rainfall and temperature over the basin. The second component consists of hydrological and hydraulic models, which transform the generated rainfall and temperature records into synthetic discharge series. Altogether this new methodology is indicated as GRADE: Generator of Rainfall And Discharge Extremes. This report gives an overview of the development of GRADE and presents preliminary results for the Rhine and Meuse rivers. The applicability of the methodology is discussed and an overview of further research needs is given.
M de Wit, TA Buishand. Generator of Rainfall And Discharge Extremes (GRADE) for the Rhine and Meuse basins