Assessment of climatic and anthropogenic effects on flood dynamics in the Cerkniško Polje (SW Slovenia) based on a 70-year observation dataset

Abstract

Study Region: Cerkniško Polje, (SW Slovenia) - regularly flooded polje with a complex recharge and partly disturbed due to human interventions. Study Focus: We focus on the long-term flooding dynamics on the polje, including analyses of trends over time, seasonal changes and identification of the impact of climate change and human construction activities on the flooding dynamics. For this purpose, we used a 70 years long dataset of continuous hydrological and meteorological measurements, and analysed documents about past human activities on the polje. New Hydrological Insights for the Region: Comprehensive analyses have revealed notable changes in the flood dynamics over past decades which mostly reflect a general drop of the water level. This is linked to both changes in the climate (lower effective precipitation) and human construction activities (regulation of the river beds, construction of dams, widening or reclogging of swallow holes). In the 1970s floods were longer and more extensive due to experimental permanent lake formation but since the partial removal of constructions, floods have become shorter and less extensive, although extreme events are more frequent than in the past. These changing patterns further impact on biodiversity, which is one of the most remarkable elements of the polje.