Sediment Transport and River Channel Dynamics in Romania – Variability and Control Factors

Abstract

Sediment transport and river channel dynamics are the result of the complex interaction between natural and human factors, at both local and regional scale. The study of sediment transport and river channel dynamics may be an important way to better know and understand the mechanisms that rule the functioning of fluvial system, allowing forecasts of its future evolution to be made and appropriate adaptation measures to be taken by society in front of the risks related to the fluvial dynamics and sediment transfer. The purpose of this chapter is to present specific aspects concerning the sediment transport and river channel dynamics in Romania and to reveal the role of various control factors. Our contribution consists mainly in regional analyses that highlight the following aspects: i) the spatial and temporal variability of suspended sediment transport; ii) the relationships between suspended sediment yield/load and some control variables (precipitation, water discharge, catchment's characteristics, and human activities), and iii) the vertical and lateral dynamics of selected river channels. The chapter summarizes a part of the significant results of our previous studies and some more recent researches in the field of sediment transport and channel dynamics in Romania. It also includes new issues and approaches, based especially on case studies, which further develop the proposed topic. The analyses focus preeminently on two areas: the Carpathian’s Curvature region, and the central part of the Romanian Plain (Fig. 1A). We have chosen the first area because it has the highest sediment yield in Romania: over 20 – 25 t ha-1 yr-1, meaning more than 10 times the average sediment yield on a national scale, which is about 2 t ha-1 yr-1 (Mociorniţa & Birtu, 1997). The central part of the Romanian Plain is characterized by an intense lateral dynamics of the river channels, making it vulnerable to the risks induced by fluvial dynamics, because of the economic importance of the area and the significant density of population and settlements. The data used and the methodologies employed are mentioned in the text. This chapter is structured in four main parts concerning: i) previous researches on sediment transport and fluvial dynamics in Romania; ii) sediment transport and control variables; iii) river channel dynamics and iii) human impact on sediment transfer.