Z. Miatkowski, S. Turbiak, W. Kowalik, A. Sołtysik, J. Lewiński

Przydatność zdjęć satelitarnych Landsat TM do identyfikacji intensywnie odwodnionych siedlisk hydrogenicznych w rejonie KWB BeŁchatów

S u m m a r y

Exploitation of minerals deposits and ground water resources is always accompanied by a change in hydrologic conditions in the surrounding areas, most often consisting in deep and extensive terrain drainage. Hydrogenic habitats, which were formed under a prevailing influence of water, are the most sensitive to changes in water conditions. Deep and long-lasting drainage of hydrogenic habitats causes transformation processes leading to their degradation. It disturbs natural and agricultural functions of grasslands.

Identification of these sites transformations and their monitoring by traditional methods, if they occur in large areas, are difficult and sometimes low-effective by traditional methods. So an attempt to use images from the Landsat TM satellite for the identification of transformed due to deep drainage hydrogenic habitats and of their range has been made. It was expected that remote sensing information from satellites which reflects the external structure of the space can help in identification and monitoring of wetlands changes due to deep and permanent drainage in large areas.

Studies were carried out in the years 1999-2003. The study area covers a region surrounding the opencast brown coal mine Bełchatów located in the southern part of the Central Polish Lowlands. For this study Landsat six scenes from the years 1987-1999 were selected. All of them corresponded to the highest precipitation deficit periods in the growing season.

An analysis of information contained in the Landsat TM multispectral satellite images, supplemented and verified with the results of direct field studies, was an effective method of identification and monitoring of hydrogenic habitats transformations in large areas, caused by their deep and long-lasting drainage. A comparison of information contained in the satellite images with information obtained by conventional methods during direct field studies showed satisfactory agreement of identification of grassland sites transformed as a result of drainage and of assessment of the range of the KWB Bełchatów ground water depression cone negative effect on grasslands. An assessment of water conditions of grassland sites in the area of the KWB Bełchatów depression cone effect, made on the basis of Normalised Difference Vegetation Index (NDVI) and by the phytoindication method (Lw) based on analysis of species composition of plant communities, gave similar results.

The method of visual interpretation of RGB composites from remote sensing data of the three bands (4, 5, 3 i 4, 7, 3) of the Landsat TM satellite and change detection analysis based on NDVI can be used to identify and monitor transformations of hydrogenic habitats caused by their drainage in large areas. Because of ambiguity of visual assessment of satellite images their verification in the field in selected, typical for a given area types of grassland sites is necessary. A combination of remote sensing and field techniques enables more accurate and more effective monitoring of the range of grassland sites transformations under the influence of deep drainage.