Flooding in Peloponnese, Greece: a contribution to flood hazard assessment

Abstract

With increasing evidences of climate change it is important to understand the hydrologic patterns of intermitternt river basin such as Evrotas river. Evrotas river is a complicated hydrologic system that experiences high flow variation such as extremely high flood events during the winter and drought events during the summer. The water management practices in combination to the limited number of monitoring stations result to high uncertainty in water mass balance estimation. To overcome this problem this study integrated ETD (Enhanced Trickle Down model), a physically-based volume balance model that explicitly represents watershed processes and a two reservoir karst model that assumes the existence of an upper (faster) and a lower (slower) reservoir that represent the two different karstic formations of the region. The estimated recharge of karst model (308.4Mm3/year) is twice greater than the river outflow (152.1Mm3/year) (mean volume of 1999-2009). This result suggests that recharge of karst plays a significant role in Evrotas river hydrology and maintains flow despite the high irrigation and evapotranspiration demands of the watershed.