BISTRIȚA RIVER CHANNEL CHANGES IN THE SUBCARPATHIAN SECTOR, IN THE LAST TWO CENTURIES
D-.A. CHELARU, I. MINEA
ABSTRACT. - Bistrița river channel changes in the subcarpathian sector, in the last two centuries. Over time, the hydrographic network corresponding to Bistrița basin has undergone numerous changes, mostly human induced, materialized through the hydrotechnical works made in order to create accumulation lakes (especially after 1960, to encrease electricity production), regularization, damming and embankment, land reclamation or achievement of adduction related to public water supply, and also for built-up area or transport routes network expansion. These actions have led to significant changes regarding the hydrographic network morphometry, by reducing the length of the river, degreasing slopes or sinuosity index. The succesion of changes was analyzed by using the following cartographic documents: Austrian maps published by von Otzellowitz (1788-1790), topographic maps (1:50.000 scale) published in 1894, military maps (1:20.000 scale) edited in 1917-1920, topographic plans (1:5.000 scale), 1975-1976 edition, cadastral plans printed in 1986 (1:10.000 scale) and 2005-2006 ortophotomaps at 1:5.000 scale. Overlapping these maps using GIS techniques highlighted the significant reduction of unplaite and sinuosity index. Also, following the deviation of the natural course of Bistrița river through the creation of a 30 kilometers drainage channel were brought important changes to the river channel morphometry, to the position and river confluences angles, and to the whole hydrographic network of the subcarpathian sector of this river.
Keywords: channel changes, human intervention, Bistrița subcarpathian sector.