Floods of the past - Design for the future

TYPE
PhD-research

Persons involved
University of Twente:
Ir. A. Bomers (PhD candidate)
Prof. dr. S.J.M.H. Hulscher (Promoter)
Dr. R.M.J. Schielen (daily supervisor)

University of Utrecht:
1 PhD-student
Dr. K.M. Cohen
Prof. Dr. H. Middelkoop

Funding of the project
STW (call WATER2015)
Rijkswaterstaat; Ministry of Infrastructure and the Environment
Deltares
Waterboard Rijn and Ijssel
Waterboard Rivierenland
Lievense-SCO
RCE Cultural Heritage Agency NL

Duration
2015-2019

Summary
Design standards for flood protection in deltas require magnitude estimates of extreme (millennial) floods. The Dutch Delta Programme considers a design discharge of 18,000 m3/s as an appropriate upper value for the Rhine River at the German-Dutch border. The design discharge was established by extrapolation of observational data. Due to the short period of discharge measurements, extrapolation discharges corresponding to large recurrence times yields a great amount of uncertainties. Extending the observational record by using historic and sedimentological archives provides an alternative solution.

Numerous historic flood marks along the Lower Rhine and sedimentary data of the youngest 2000 years contain valuable information, notably on extreme floods in 1651, 1374, 1342 and ~784/5 AD. The project will quantify magnitudes of large historic floods of the Lower Rhine. The interdisciplinary project will combine sedimentary and written archives from the delta with state-of-the-art reconstructions and 2D hydrodynamic modelling of past events in a scenario-approach. Sensitivity analysis will be performed to investigate the uncertainties during historical modelling. The resulting generic method to quantitatively explore historic river floods, allows evaluating potential limits to design flood magnitudes and inundation cascades in the current situation in the Netherlands and adjacent Germany, contributing to the Water Safety theme. Subsequently, GRADE (newly developed method to determine design discharges) will be validated and recommendations for optimization will be given.

The proposed research accommodates two PhD-projects. The first PhD project will focus on the reconstruction of historical flooded landscapes using historic maps, sedimentary archives and geomorphological data (University Utrecht). The second PhD project will focus on the parametrization and translation of hydraulic characteristics of the river and floodplains of the various historical years and use this as input for the hydraulic models to reconstruct past flood magnitudes (University of Twente).