Historical land use changes and their impact on sediment fluxes in the Balaton basin (Hungary)

Agricultural land use changes can influence soil erosion process. The objective of this study was to investigate impact of historical land use changes on soil erosion and sediment transport in the Kali Basin study area, a small catchment located in a national park at Lake Balaton, Hungary. The Kali Basin is of high landscape value where vine (Vitis spp.) growing has been ongoing since the Roman times. Lake Balaton is a recreational area of international significance, thus research on sediment and nutrient fluxes is of paramount importance for lake protection. The SEDEM/WATEM distributed erosion and sediment transport model was used to calculate sediment fluxes from the Kali Basin catchment into the lake. The model was calibrated against long-term measured suspended sediments at the catchment outlet and it was validated against independent soil survey data. Application of GIs methods for model development and interpretation was emphasised. Results showed that, despite the low overall sediment export from the catchment, land use changes introduced by property ownership and agricultural changes have decreased average sediment production in the catchment but increased relative sediment export to Lake Balaton. This is due to changes in the land cover pattern that allow more sediment transported to the river system. Erosion impact of dramatic land use changes such as change to centrally directed economy after the WWII and transition to market economy a decade ago in the study area are discussed. Similar land use changes due to socio-economic changes are typical in most of Central and Eastern European New Member States and Candidate Countries, thus the investigation of similar sites is an important contribution to the understanding of erosion impact of land use changes and to efficient agricultural and landscape management in the enlarged European Union. (c) 2005 Elsevier B.V. All rights reserved.