Different Response on Land-Use Changes and Channel Management in Two Headwater Catchments of the Nysa Szalona Catchment (SW Poland): Channel Morphology, Riparian Vegetation and Hydrology

Large-scale flooding in Eastern Europe forms dramatic constraints for the future economic development of the region. Apart from the excess of water, the hinterland also delivers large quantities of sediment, which accumulates in downstream reservoirs or forms problems in the fairway. To understand the processes of water and sediment generation in the headwaters of the major waterways it is important to look at these processes on a scale that is large enough to be representative of the processes involved and small enough to be homogeneous and thus allow unambiguous results.

In the meso-scale Nysa Szalona catchment SW Poland an ongoing investigation involving the interaction between land use and sediment and water delivery is carried out. The determining factors influencing the sediment and water delivery from this meso-scale headwater catchment were assessed.

In this research, two sub-catchments of the Nysa Szalona were thoroughly surveyed. The geomorphology of the channel and the ecology of the riverine habitat was surveyed with a small airborne photo camera. These photographs were used as a basis for several land-use scenarios to calculate possible ecologically friendly solutions to reduce the sediment delivery to the main channel and to retard the flood wave in the meso-scale headwater catchments. These scenarios were assessed on effectiveness with a GIS-based sediment delivery model and a simple rainfall-runoff model.

The sub-catchments of the Nysa Szalona are similar in terms of land use, geology and landscape. However, the response to precipitation differs, which is due to differences in channel management and changes in land use. The geomorphology and vegetation characteristics of these two sub-catchments were linked to discharge measurements.