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• Studying floodplain roughness in an Upper Tisza study area

  85-90

  Róbert Vass

  Zoltán Túri

  Views:

  215

  Floods slowing down due to the significant decrease of the gradient have considerable sediment accumulation capacity in the floodplain. The grade of accumulation is further increased if the width of the floodplain is not uniform as water flowing out of the narrow sections diverge and its speed is decreased. Surface roughness in a study area of 492 hectares in the Upper Tisza region was analysed based on CIR (color-infrared) orthophotos from 2007. An NDVI index layer was created first on which object-based image segmentation and threshold-based image classification were performed. The study area is dominated by land cover / land use types (grassland-shrubs, forest) with high roughness values. It was concluded that vegetation activity based analyses on their own are not enough for determining floodplain roughness.

• Water chemical analysis of the oxbow lakes near the Upper-Tisza River

  36-42

  Beáta Babka

  Szilárd Szabó

  Views:

  93

  The Tisza river plays an important role in the life of Eastern Hungary. Beside the river there are several oxbow lakes, cut off meanders. In this paper the water quality of these lakes was examined from the section of Tarpa to Rakamaz. 45 oxbow lakes were sampled and the chemical parameters were determined. Sodium was used as a pollutant (sewage water) indicator and 2 lakes were found extremely polluted. The lakes outside the dam were slightly polluted because of the lack of renewal of the water body and the ones in the active floodplain had good quality parameters.