Water level control at Kaunas dam during flood period

Abstract

The biggest damage which can occur due to floods in Lithuania Kaunas Hydropower (HS) system, which consists of Kaunas Hydropower Plant(KHP),Kaunas reservoir, Kruonis Pump Storage Plant (KPSP) and its upper artificial reservoir, is its failure.Fllod control problem in HS is multi objective and complex which requires optimal solution between many parameters such as: flood inflow into reservoir, nominal water level near the Kaunas dam, nominal water level near the KPSP, discharge through the dam, acceptable risk level related with dam failure, acceptable water fluctuation in the reservoir and also from economical point of view-useful reservoir capacity. The present work is concentrated more on the situations related to extreme floods with return period larger than 200 years. The developed control method is risk based method, which includes risk measures evaluated using risk analysis methods and as a main input considers the flood flow forecast. Flood flow forecast model is a physically based degree-day snowmelt and coupled with flow routing via NASH's IUH theory. Temperature forecast is used as a driving variable to feed the degree day model. The main issued results of the model are risk based control alternatives and offer the optimal solution for water discharge through the dam.