Combining the Results from the Production Runs into Databases (SWAN, WAQUA, Bretschneider)

As preparation for the 2017 assessment of the strength of the Dutch primary water defences, a number of hydraulic databases were made. These databases are required for Hydra-Ring in order to transform combinations of random variables (e.g. wind speed, river discharge) into Hydraulic Boundary Conditions (water levels, wave conditions), which can subsequently be used to determine the hydraulic loading on the flood defences. Databases were made for three regions: tidal river area (RMM), the Ijssel-Vecht Delta (IJVD), and the non-tidal river area (Rijnbranches, Maas). For the Maas region there are two schematizations, the Maas and the Maas mknov (infinitely high Maaskaden). Databases are made for locations along the dikes, and locations along the river axes. These databases contain water levels and wave conditions for a number of combinations of random variables. The general procedure for making the databases involves post-processing the WAQUA water level results by means of a low-pass filter and combining these results with wave conditions in a database structure. Furthermore, the procedure involves either replacing or discarding information that we do not trust. This procedure is described in detail in the present report. In order to determine whether enough information is included in the databases for HydraRing, an analysis was done to evaluate the filling of the databases. Although gaps exist, it was determined that sufficient information is present in the databases for use in Hydra-Ring.