Einfluss der Hydromorphologie auf den Nährstoffrückhalt in Weinviertler Bächen – Schlussfolgerungen für das Gewässermanagement | The impact of hydro morphology on nutrient retention in the streams of the Weinviertel region in Lower Austria – conclusions in terms of stream management
2011
Weigelhofer, G. | Fuchsberger, J. | Teufl, B. | Kreuzinger, N. | Muhar, S. | Preis, S. | Schilling, K. | Hein, T.
Large-scale regulation in the past and intensive farming in this area have substantially degraded the morphology of a large number of minor streams in the Weinviertel region and have severely impaired the water quality through nutrient pollution. The influence of hydro-morphological factors on the water and sediment quality as well as on the capacity of nutrient retention in the water body have been studied in a project ProFor by ETZ in order to develop rehabilitation ideas for severely affected upper stream sections in that region with the aim of improving the nutrient balance. The studies have revealed accumulations of nutrient-rich, organically polluted fine sediment from eroded farmland with a high release potential for ammonium and phosphate (up to 20 mg m−2 h−1) mainly in the degraded reed-covered stream sections. Nutrient retention was generally not satisfactory. The average transport distances for dissolved nutrients usually amounted to several kilometres, while the average rates of ammonium and phosphate uptake ranged around 5 mg−2 h−1. Sections bordered by woodland normally exhibited a better sediment quality and a higher level of nutrient retention than degraded sections. The results of the study show that a reduction of nutrient pollution and an improvement of the ecological functioning of streams, in particular with a view to restoring their self-purification capacity, can be achieved only by a combination of measures aiming at restructuring the stream morphology while reducing the amount of contamination from surrounding soils.
显示更多 [+] 显示较少 [-]