Changes of Hydrographic Network of Uściwierskie Lowering According to Cartografic Materials

The paper analyses a hydrographic network and its changes in the area of Uściwierskie Lowering in last 180 years. The Uściwierskie Lowering was originally the second largest closed drainage depression in Łęczna-Włodawa Lakeland, with an area of 45.83 km2. The increasing anthropopression mainly by melioration works led to significant changes. The authors use early and modern maps to analyse the quantitative aspect of these changes. The technical issues of georeferencing maps in the Geographic Information System (GIS) software are addressed first. In case of some maps, georectification happened to be problematic. 19th century topographic maps (as the Quartermaster map) were of much lower geometric quality compared to early 20th century and modern maps. Also the poor settlement in the area resulted in lack of ground control points useful in case of georectification. Using such data can, however, be justified by the fact that little is known about changes in the hydrographic network of the region during the 19th century, while the period of last 50–100 years is examined with more details. The results show the numeric values illustrating quantitative changes in the area. They are also a step forward towards understanding the degree of anthropogenic transformation of a drainage network. It is vital as these changes influence the whole ecosystem – lowering the water level shapes habitats and change the landscape.