2949775667

GEOGRAPHIA POLONICA 68,1997

THE INFLUENCE OF ANTHROPOPRESSURE ON WATER

RELATIONS IN THE WIELKOPOLSKA LOWLAND

Alfred Kaniecki

Institute of Physical Geography, Adam Mickiewicz University

Fredry 10, 61-701 Poznań, Poland

ABSTRACT: This contribution describes the influence of anthropopressure on water conditions in the Wielkopolska Lowland. In particular this is connected with gaining new areas for agriculture: firstly through deforestation and then through drainage of marshy areas. As an effect of this hydro-economic activity of man the natural cycle and balance of hydrological processes have often been interrupted. This is particularly visible in the modification of the hydrographic network; e.g. changes in river routes, the elimination of some rivers and lakes, the loss of marsh areas and the regulation of outflow conditions in rivers. Dewatering of the Wielkopolska Lowland has progressed for around 1000 years and is manifested in the form of increasing water shortages.

KEY WORDS: anthropopressure on water conditions, water management, drainage work, Wielkopolska Lowland, Central Poland.

In the last millennium, the natural environment of the Wielkopolska Lowland has undergone intensive changes primarily related to man’s economic activity. The changes have affected the vegetation cover, soil and water relations and, in some areas, also their hydrographic pattern. In generał, the process of change was very slow and as such could not be perceived by the inhabitants, especially sińce their average life span up to the 19th century did not exceed 30 years. Changes of this type can only be observed in retrospect, after they have become Consolidated and have assumed certain features of stability.

The changes in the natural environment related to man’s economic activities and natural climatic changes have overlapped and we cannot clearly determine or separate these effects. For instance, increased climatic humidification has madę river valleys morę marshy, but a similar change could also result from dividing a valley with a road embankment stopping or limiting the drainage of water from its upper regions. On the other hand,