Flood Management at Dams with Consideration of the Reservoir Operation

Dealing with design work in the fields of water management requires design values and data. Firmly connected with this circumstance is the question, how to obtain such design values and which risk corresponds with them. This is particularly valid for designing spillways of dams, which not only serve the purpose of water storage but also flood control. A research project aims at developing a new design concept under consideration of reservoir management. The development and practical application of the proposed method - originally by R. Pohl (1999) - is carried out in the context of case studies for reservoirs of hydro power plants in Austria. The computed water level as design value results from three main load values, namely the random initial reservoir water level at the beginning of a flood event, the additional elevation height due to a random flood event (inflow) and a required freeboard height due to a random wind event. According to this, the design value itself also is a random variable, which can be estimated by means of the method of statistical trials (Monte Carlo Method). The main advantage of this probabilistic design method is, that the overtopping risk of dams under changing loads could be estimated and so risk analysis is made possible.