The design of a river-basin-specific flood hydrograph generator based on gauge records enables the generation of synthetic flood hydrographs for the dimensioning of hydraulic structures. Based on selected flow time series, flood waves can be described using four parameters based on flood characteristic simulations, as described by Leichtfuss and Lohr (1999). After successfully adapting suitable distribution functions, dependencies in the load structure are quantified in the next step using copula functions. This newly developed approach builds on the procedure proposed by Bender and Jensen (2012), which assumes hydrological independence. Using copula functions results in increased accuracy in the extended flood characteristic simulation. Moreover, considerable enhancements are achieved through the utilization of genetic algorithms, wherein the descending branch of the flood hydrograph is adjusted by employing an additional variable factor. Subsequently, any number of synthetic flood hydrographs can be generated by combining these parameters. In keeping with the principle of Monte Carlo simulation, a sufficiently high number of synthetic events results in extreme conditions with a low probability of occurrence being reliably represented. Hence, this endeavor has the potential to enhance result reproducibility and prediction quality. As a result, this expanded approach can be employed to provide dependable assessments regarding inflows aimed at optimizing reservoir capacity, for instance.

Conceptual overview of the proposed hydroinformatic workflow. Geospatial raster inputs (bathymetry, wave height, and wave period) are processed using analytical wave theory and a parallelized computational framework. The workflow leverages CPU and GPU acceleration to compute near-bed orbital velocities across large raster domains, achieving significant speedup and reduced memory usage. This technical note introduces an efficient workflow for the large-scale computation of near-bed flow velocities under wave action, based on linear airy wave theory. As a case study, rasterized datasets of bathymetry, significant wave height, and wave period for the German Bight are used to estimate the maximum orbital velocity at the seabed. This is implemented within a modular hydroinformatic framework, combining geographic raster data (pre-)processing using pluggable models and interactive visualization. It employs just-in-time compilation via the python library Numba. This allows for execution across all cores of the Central Processing Unit (CPU) or, if present, a Graphics Processing Unit (GPU) using the Compute Unified Device Architecture (CUDA) architecture. This design facilitates large parallel computation across thousands of CUDA cores, enabling faster processing of extensive raster domains for iterative model refinement. Performance benchmarks reveal a more than fourfold reduction in runtime and 70% lower memory consumption compared to a standard CPU implementation. The findings underscore how classical hydrodynamic formulations can be effectively integrated into scalable, open, and reproducible workflows for rapid spatial evaluation of marine processes. The presented method offers a practical foundation for area-wide analyses of seabed dynamics, offshore engineering design, and morphodynamic sensitivity studies within modern hydroinformatics.

In the analysis regarding the stability of river dikes, the interactions between the load magnitude of the flood level and the resulting percolation are found to be a highly relevant process. After all, the seepage line separates the cross-sectional area into the water-saturated and the unsaturated crosssectional parts. For homogeneous levees, the position of the seepage line in the stationary case is imprinted in the system by the outer cubature and is well on the safe side for real flood events. In the non-stationary case, the position of the seepage line depends primarily on the changing water level of a flood hydrograph, the resulting water content and suction stresses in the dike, as well as the saturated permeability of the dike construction materials. In the current dimensioning practice according to DIN 19712 and the German DWA-M-507, the characteristic of the hydrograph is not directly applied. So far, for example, the resulting damming duration of a flood hydrograph is only considered indirectly.This paper presents a methodology, which quantifies natural dependency structures for a selected dike section by synthetically generated dimensioning hydrographs in a probabilistic design. These results are then integrated directly into the geohydraulic process of water penetration. Based on selected water level and discharge time series at a dike section, flood waves can be described in five parameters using the extended flood characteristic simulation according to MUNLV1. After successfully adapting suitable distribution functions, dependencies in the load structure are quantified in the next step using Copula function. Subsequently, any number of synthetic flood hydrographs can be generated by combining these parameters. In keeping with the principle of the Monte Carlo simulation, a sufficiently high number of synthetic events results in extreme conditions with a low probability of occurrence being reliably represented.Using a developed routine, the process of moisture penetration for the individual flood hydrographs can be simulated and visualized in a transient, geohydraulically numerical model at different points in times. Finally, statements regarding the behavior patterns of the resulting seepage lines, based on the loading situation can be derived and predicted. Based on these results, a reliability analysis then shows the stability of the dike section under the given extreme conditions.1Ministerium für Umwelt, Landwirtschaft, Natur und Verbraucherschutz des Landes Nordrhein-Westfalen