Measurement of the Catchment Area of the Rivers of the Kłodzko Basin Using QGIS Software

Knowledge of the catchment area is essential for hydrological analyses. With it, it is possible to determine the water flow rate at the cross-section enclosing it. Nowadays, measurement is possible thanks to computer techniques that continue to develop in order to determine its area in the most effective way, i.e. as quickly and precisely as possible. The aim of this paper was to investigate the differences in the resulting catchment areas based on the Digital Elevation Model at different resolutions. One method of calculating catchment areas using the QGIS software and its tools is presented, using the example of a section of the Nysa Kłodzka River and its tributaries. The results were compared to plots made available by IMGW, which were treated as baseline data. Attention was paid to what could cause differences in the results obtained and which model would work best for which case.