Author(s): Matija Brencic; Andrej Sirca; Gasper Rak; Franci Steinman

Linked Author(s): Andrej Širca, GAŠPER RAK, Franc Steinman

Keywords: HPP chain; Dam break; Embankment breaching; Malfunction; Contingency plans

Abstract: Dams and embankments of HPPs operating in a run-of-river regime with headwaters reservoirs play important roles in hydropower generation, flood control, navigation and recreation benefits. At the same time, they could present a threat to adjacent and downstream areas. A failure of a hydropower plant dam, embankment breaching or malfunction of hydro-mechanical equipment and anthropogenic influences could have catastrophic consequences for human lives or economy. For predicting consequences and preparation of unforeseen events, simulations of various scenarios are needed in the phase of HPP facilities design and preparing their operation rules. This paper presents the results of hydraulic and spatial analysis for the HPP chain on the lower Sava River in Slovenia. Along an appx. 60 km long section of the Sava River there is a chain of low-head hydropower plants in the final stage of construction (Q = 500 m3/s, H = 8 – 11.5 m). Many settlements and infrastructure are located in the flood-prone areas of the Sava River. They are protected to the level of a flood discharge with a 100-year return period. At its downstream end, the treated Sava River section terminates on the State border with the Republic of Croatia. For selected 50 most critical scenarios of dam and embankment breaching and irregular or limited operation of the hydro mechanical equipment at hydraulic structures, numerical simulations were performed using 1D-2D hydraulic modelling to determine a situation development, extent of flooding, propagation and transformation of flood waves. Results of hydraulic and spatial analysis were later used in development of event ranking and coordinated operating instructions and procedures for individual HPP facilities and HPPs chain as a whole. An analysis was established and performed on the basis of the applicable legislation in cooperation with design and management companies of HPPs.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022559

Year: 2022