Modelling sediment supply to rivers and reservoirs in Eastern Europe during and after the collectivisation period

At present, the landscapes in the former communist countries of Eastern Europe are undergoing a second major change in 50 years. After World War II, collective agricultural systems, such as the United Agricultural Cooperatives and the State Farms, were established. Following the example of the Soviet Union, individual fields were put together in order to enablemass production. This, however, led to an enormous acceleration of erosion and sediment transport processes on arable land. Since the fall of the communist regimes in 1990, farmers, or their successors, can claim back their original property. The large collective fields are split up in smaller spatial units. The land that is not claimed back is abandoned. This new transition has again a huge impact on soil erosion and sediment export to rivers and reservoirs. In order to control and optimize the transition from collective to private farming systems, land arrangement administrations need modeling tools to simulate the geomorphic impact of possible future land use scenarios. In this paper, SEDEM, a spatially distributed sediment delivery model, is calibrated and validated with measured sediment yield data from Czech drainage basins. The results suggest that SEDEM is able to predict the impact of land use changes on the mean annual sediment supply to rivers. Next, SEDEM is applied to assess the impact of a range of possible future landscape scenarios such as the splitting up of large fields in smaller spatial units and conversions from arable land to pasture.