WATER RETENTION IN NATURAL AND TRANSFORMED FLOODPLAINS AND ITS IMPACT ON ECOSYSTEM SERVICES

David Pithart, Daphne ČR, Institute of Applied Ecology, České Budějovice
Tomáš Dostál, Czech Technical University, Prague
Jiří Žaloudík, Czech Academy of Sciences, South-Bohemian Biological Centre, České Budějovice
Kateřina Křováková, University of South Bohemia, Laboratory of Applied Ecology, České Budějovice

Abstract

Most of european floodplain have lost its water retention capacity by transformation aimed at intensive agriculture management. What benefits connected with water retention we have lost? Can we express them also as economic values and compare them with economic benefits of intensive agriculture? This study is based on comparing floodplain segments – natural and transformed rivers in the Czech Republic. We have quantified their  hydrological regime and flood wave transformation effects by hydrological modelling, we have mapped their biotopes and evaluated biodiversity, estimated production of agricultural comodities including fish and estimated carbon sequestration. Especially we focused on water distribution within the floodplains, ie processes as inundation, infiltration and evapotranspiration. Among ecosystem services flood mitigation, biodiversity refugium, carbon sequestration, production and recreation have been designated. Overall ecosystem service analysis showed the economic value of preserved floodplain was remarkably higher if compared to transformed one, even if biodiversity was not included. Water distribution showed the inundation over the floodplain area is essential for any significant flood mitigation, while evapotranspiration may have an cooling effect on the microclimate, detectable by aerial thermovision imaging.