Michał Szydłowski

Numerical simulation of catastrophic flood: the case study of hypothetical failure of the Bielkowo hydro-power plant reservoir

The numerical modeling of flood wave propagation following the hypothetical breaks of the embankments of the Bielkowo hydro-power plant storage reservoir (Kolbudy II Reservoir) on the Radunia River in Poland has been presented. The results of computations were used to estimate the parameters of the flood waves, which are indispensable for the flood zone determination and mapping and then for the flood risk analysis. When estimating the reach and area of the inundation, related to the embankments failures, digital terrain model, and mathematical model of flood wave propagation are necessary. For the numerical simulations of flood, the mathematical model of free surface, two-dimensional unsteady water flow was applied. Four locations of potential breaks of the reservoir embankments were considered. The computed flood zones were presented on the flood hazard maps. The maps have been used by the local authorities and the dam owner to manage the flood risk related to hydro-power plants operations on the Radunia River. This type of research has been done for the first time for the water plant managed by the ENERGA Elektrownie Straszyn.

Application of Hydrodynamics Model for a Case Study of the Kolbudy II Reservoir Embankment Hypothetical Failure

The aim of the chapter is to present an application of the numerical simulation of flood wave propagation following a hypothetical break of the embankment of Kolbudy II reservoir located at the Radunia River in Poland. The estimation of the reach of inundation following the embankment failure requires a digital terrain model (DTM) and a mathematical model of flood wave hydrodynamics. The digital elevation and land development models were created using an orthophotomap. For the hydrodynamics mathematical model of free surface, a two-dimensional shallow water flow was applied. The location of potential breach was selected as an example of hypothetical failure of one of the four Kolbudy II reservoir dikes. The computations were finally used to determine the flood risk maps. The maps have been used by the local authorities and the dam owner to manage the flood risk related to the Bielkowo hydropower plant operation.

Numerical Modeling of Water and Ice Dynamics for Analysis of Flow Around the Kiezmark Bridge Piers

This paper presents the results of a numerical model study on the effect of ice on the proposed bridge piers in the Vistula River outlet and its effect on flow conditions in the river. The model DynaRICE is used in this study, which is a two-dimensional hydro-ice dynamic numerical model developed for dynamic ice transport and jamming in rivers. To simulate river hydrodynamics in the vicinity of the bridge piers, two-dimensional numerical model basing on finite volume technique was also used. Simulation results indicated notable effect of new structure on water and ice flow pattern. Ice forces on structures were also determined, but the load was not considerably high.

INTERACTION BETWEEN STORM WATER CONDUIT AND SURFACE FLOW FOR URBAN FLOOD INUNDATION MODELLING

Rapid development of urban areas always comes with great side effects. One of them is the occurrence of urban floods. Growth of impervious surfaces in cities leads to increasing run-off values. This together with difficulties connected with sewage modernization in cities marks urban inundations as being one of the most important issues concerning urban water. Accurate prediction of a phenomenon is difficult as it is highly dependent on local conditions and the quality of available data about them. A most recent approach to modelling urban flooding involves a detailed description of the interaction between storm water sewage flow modelling and surface flow modelling. In this paper we will describe a numerical model of urban inundation that is being used to analyse the phenomenon, which consists of 1D storm water flow model (explicit McCormack scheme) and 1D surface flow model (diffusive wave). But before that laboratory tests describing the interaction between used models will be introduced. We will try to evaluate how different surface flow conditions affect interaction and find out if there is an easy way to implement it in coupled numerical modelling of large-scale urban areas inundations. Because tests are still being conducted and further investigation of phenomenon is being done, the conclusions are only preliminary and should be treated as a guideline for future work.

Interaction Between Storm Water Conduit Flow and Overland Flow for Numerical Modelling of Urban Area Inundation

Nowadays we can observe increasing frequency of inundations in cities. This makes accurate predicting of inundations more important than ever. Numerical modeling of this issue requires complex approach with simultaneous calculations of pipe flow and surface flow. In this paper, after a short review of known methods used for solving pipe and surface flow, we will try to answer the question if presented methods would be sufficiently accurate for inundation modeling. We will also investigate if known formulas used for modeling interaction between pipe and surface flow describe the issue well and if they can be developed in any direction. There will be presented comparison between results of calculations and experiments built on test stand made for this purpose in Gdansk University of Technology. The results could be treated as a starting point for further recognition of the phenomenon.

Hydraulic Conditions of Flood Wave Propagation in the Valley of the Narew River after the Siemianówka Dam Overtopping Failure

In this paper, the results of the dam break wave forecast in the valley of the Narew River, after the failure of the Siemianowka Reservoir earth dam, are presented. The Siemianowka Reservoir was built in 1991 due to the planned agricultural management of the Narew Valley. It is located in the Upper Narew Catchment as a typical lowland reservoir of a low mean depth, equal to 2.5 m and the principal spillway of 145.00 m above sea level. The reservoir is located about 82 km upstream of the border of the Narew National Park and considerably influences the hydrological regime of the Narew River within that park. The total capacity of the reservoir is 79.5 million m3. The presented example of calculations for the Siemianowka Reservoir underlines the most important issues related with the forecast of the dam break, that is: the determination of maximum water levels and discharges in the valley downstream of the failure dam, the calculation of wave-front occurrence time at particular points of the valley, the inundation range along with the longitudinal profiles of water levels and velocities of water on inundated areas. The knowledge of the water depths on inundated areas, the duration of inundation and maximum water velocities enable as well the estimation of the damage degree on inundated areas. As it results from the calculations, the washout process of the Siemianowka Reservoir earth dam, which is 6 m high, happens very quickly, and after about 2 h the top of the triangular breach reaches the dam bed. The discharge from the reservoir after dam failure drops from 465 to 304 m3/s and the water level in reservoir decreases 1.36 m as fast as within 300 h. The occurrence of wave in the valley causes the increase of water levels by 0.1–4 m in comparison to the water level before the dam break, and a 4-time increase of discharge rate in relation to the design flow at the cross-section of the dam of the Siemianowka Reservoir. The velocity of the wave-front propagation in the Narew Valley does not exceed 5 km/h.