Inventing a hydraulic river modelling approach to simulate high flow and low flow conditions

Global climate change affects all aspects of river
processes. It is expected that discharge
extremes will occur more often in the future and
that the possibility of having discharge extremes
in terms of high and low flows in a shorter period
will increase too. More specifically, for the Rhine
River in Germany and the Netherlands, high
discharges in winter are expected to become
more severe, whereas low flows will occur more
often and over a more extended period in
summer and autumn. Given these changes in
climate conditions, the question arises whether
it is possible to have an integrated hydraulic
modelling approach to simulate high and low
flows in rivers.
One of the advantages of a single model for
low and high flows is the tendency towards
integrated river management. For example, the
implications of measures targeted to high flows
should not have negative consequences for low
flow conditions and vice versa. Currently, the
calibration procedure is one of the reasons to
employ two separate models instead of one
calibrated model.
Calibration means minimizing the errors
between simulated and observed water levels
by modifying model parameters for a specific
situation. These errors could be caused by e.g.
uncertainties in the input data and mesh
discretization in hydraulic models. The primary
purpose of this study is to develop a single
model with one calibration approach that could
simulate the water level accurately for different
discharge ranges. In this regard, the first step is
to study the current state of hydraulic calibration
approaches applied in the literature. The
second step is to find a suitable model set-up for
such a model. The third and fourth steps are
finding the most promising calibration approach
and how this calibration approach can be
improved such that a hydraulic model can be
calibrated and applied for varying discharge
conditions and finally validated for an entire
hydrograph.