Geomorphometric analysis on the some riverbeds in the Romanian plain

Abstract

The present study refers to some hydrographic basins in the Romanian Plain and appeals to morphometric methods based on the Horton Strahler river hierarchy system. The central part of the Romanian Plain located between ArgeAŸ (East), Olt (West), Cotmeana Piedmont (North) and Danube (South) has a highly dense hydrographic network. The Vedea and Neajlov basins (for which the major source of the trunk river is located in the alluvial deposits, rich in phreatic waters, were analyzed) and Calmatui, this explains the relatively high density of the drainage network in the upper part of these basins, proved by the high values of the confluence ratio for the low order streams (Rc1 = 5.56 – Cotmeana (river trybutari of Vedea); 5.15 – Neajlov; Vedea = 5.73). This is an unusual situation for a plain river but it is sustained by Schumm et al. (1995) demonstrations regarding the genesis of rivers of Stepheads type. The riverbed morphometry and morphography reflects the long-term dynamics and evolution, the employed models being complex and depending on the envisaged purpose. In the south-western of Plain Teleorman is the basin Calmatui, with high confluence ratio (Rc = 6.4). The geomorphometric analysis in the Horton-Strahler system accurately reflects differences among riverbeds as follows: a high value of the bifurcation ratio for the Vedea upper basin (at the contact plain-piedmont), oversized channel of the Neajlov, autochthonous Plain River (old riverbed of a Subcarpathian stream, high underground recharge rate from the ArgeAŸ alluvial fan). The values of morphometric parameters, obtained through direct measurements on maps emphasize riverbed dynamics. The cartographic document similar to present maps is the old cartographic document. Key words: Riverbeds, geomorphometric analysis, drainage basin, Romanian Plain.