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In this paper old historical maps and the sheets of the Habsburg Military Surveys are analyzed to distinguish different terrace levels in the Great Hungarian Plain (GHP), and particulary in the Körös/Criş river system. The GHP is located in the Pannonian Basin, in the eastern part of Hungary, which is a very flat area. Prior to the river regulations, its meandering rivers (eg. the Tisza and Körös Rivers) flooded the lower areas and created marshlands. The method of the integrated analysis of these different maps was the georeference; to geometric fit the sheets from different sources. While the First Military Survey shows the original extents of these areas the Second Survey displays the situation of the environment at the time of the flood control works in the second half of the 19th century, also with the planned cutoffs. The maps show not only the rivers, but the settlements as well. During this period, these villages and towns became bigger, so they needed more and more agricultural area. They cleared the forests and dried out the marshlands to have more ploughlands. These land types can also be separated easily in the survey sheets. Two study areas were selected to show the effectiveness of environmental reconstruction at some local engineering surveys and the Military Surveys, too. The extents of the different elevation terraces are mapped with striking accuracy.

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The Sárrét marshland is situated along the northeastern foothills of the Bakony Mountains, along a NE-SW-trending neotectonic zone. Investigation of the marshland and the reconstruction of its evolution are especially interesting to compare to the present and the expected future stage of Lakes Balaton and Velence. Based on the sedimentological characteristics of the core sequence and the geochemical, physical, and mineralogical composition of the layers, three sedimentological cycles could be separated. The three cycles represent the most important evolutionary phases of lake formation: flourishing and progressive aging. First, a nutrient-poor, open-water lake existed, where clastic sediments (sand and silty clay) were deposited. During the second phase, phytoplankton-produced autogenic lime mud was deposited in the progressively more eutrophic water. Peat accumulation during the third stage indicates the marsh phase of the lake.The results suggest that the studied sequence developed from Late Glacial to Middle Holocene. According to radiocarbon dating the accumulation rate in Sárrét (Sümegi, this volume) corresponds to the sedimentation rates in the Tapolca Basin and Lake Balaton.

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