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T. Wilgat et al.

The hydrosphere of the Lęczna-Wlodawa Lakę Region is, as has been stressed, very liable to transformations. However, this region was thinly populated for ages, and primitive farming did not cause significant changes in the environment. Simple hydrotechnical measures were taken here for a very long time, but till the 1960’s they did not effect the character of water relationships. Since that time morę and morę conspicuous changes have occurred, as a result of intensified farming and increasing use of the lakes for recreation. Coal mining has become another new factor appearing here. Its role cannot be compared with those of the others because its influence on the hydrosphere is not confined to the zonę of active water exchange, but also effects deeper water-bearing horizons.

CHANGES IN LAND USE AND THEIR HYDROLOGICAL CONSEQUENCES

Chronologically, the first transformation factor in the hydrosphere was the extirpation of forests and their changing to arabie land. No data are available to determine the exact time when the process started. Therefore, attempts to reconstruct the changes of the primary environment are undertaken on the basis of the results of studies of settlement and farming. For the Lublin district in its historical bundaries — neighbouring from the East with the Lęczna-Wlodawa Lakę Region — changes of land use in several periods of time were presented by Maruszczak (1987). According to this study, 83—88% of its area was covered with forest in the year 1000 — the dawn of Poland’s history; by 1340 this index had decreased to 73—77%, by 1580 to 44—4:8%, and by 1824 to 36%. In 1980 its woodland was only 20.5%. Arabie land increased in parallel, exceeding 50% at the beginning of the 19th century, and constituting 71% in 1980. From the data it appears that the deforestation ratę varied. It was Iow in the early Middle Ages, increased considerably in the late Middle Ages with increasing population density and changes in the cultivation system and land holding (feudal farming). It decreased again in the 17th c., when Poland entered a period of long economic stagnation and devastating wars. Population increase in the 19th c. and growing land hunger became the cause of a repeated, considerable intensification of deforestation.

In the Łęczna—Włodawa Lakę Region the primary forest cover was lower than in the Lublin district, because open waters, swamps and wetland scrub constituted a bigger percantage area. Higher land stretches were deforested, but poor soils and a sparse population did not favour the development of agriculture. ATopographical Chart of the Polish Kingdom at 1:126,000 (issued in 1839) gave a relatively credible first image of land use in the Lakę Region area, reproducing the state existing there in about 1830. The Lakę Region is presented as a mosaic of arabie land, forests, shrub patches, meadows and swamps with lakes scattered all over its area. Forests occupy less than 50% of its area but predominate over other natural or almost natural terrain in the landscape in which cultivated fields form smaller or larger enclaves.