Geoscience Reference
In-Depth Information
Application of Hydrodynamics Model for a Case
Study of the Kolbudy II Reservoir Embankment
Hypothetical Failure
Michał Szydłowski
1
Introduction and Case Study Description
The Polish law requires an analysis of catastrophic flood events following hypo-
thetical failures of dams and reservoir embankments. According to the regulations
of the Polish Minister of Environment concerning technical conditions for hydro-
technical structures and their location, the catastrophic flood ranges must be
determined for dams with total water head greater than 2 m or water capacity
greater than 0.2 million cubic meters. The chapter presents an example of numerical
simulation of flood wave propagation resulting from hypothetical embankment
break of the Kolbudy II reservoir, being part of the Bielkowo hydro-power plant.
The Bielkowo power plant is an element of hydro-power system of the Radunia
River (Majewski et al.
2005
). The Radunia River is situated in the Pomeranian
Voivodship (Poland) and is controlled by the Gda
´
sk Board of Water Management.
The hydrotechnical structures on the river are owned and operated by ENERGA
Elektrownie Straszyn Ltd.
The hydrotechnical system of the Bielkowo hydropower plant is presented in
Fig.
1
and can be described, after Jarz˛bi
´
ska (
2005
), as follows. The system
consists of control weir Kolbudy, diversion channel, two reservoirs (Kolbudy I
and Kolbudy II), concrete power tunnel, surge tank, steel penstock, and hydropower
plant operating on the head of 44.25 m. The total water head was formed due to 4-km
long water diversion between two cross-sections of the Radunia River on the steep
8 km segment of the river. The weir Kolbudy forms the reservoir Kolbudy I and
controls the flow between the river and diversion channel. The channel carries water
to the Kobudy II reservoir with the maximal discharge of 20 m
3
/s. A total length of
the canal is 1,350 m, and its typical cross section is trapezoidal. At the outlet from
the channel to the reservoir, a second small control weir is located. Reservoir
Kolbudy II was formed by constructing four earth dams closing the natural lowland
