Gabriela Adina MOROSANU, Institute of Geography of the Romanian Academy, Romania
Liliana ZAHARIA, University of Bucharest, Faculty of Geography, Romania
Gabriela IOANA - TOROIMAC, University of Bucharest, Faculty of Geography, Romania
In October 1972 the Jiu River (an important tributary of the Lower Danube River) experienced a high magnitude flood with significant human and material damages. Following this event, the authorities at the time implemented a series of structural measures for flood risk mitigation. In the lower sector of the Jiu River, south of Filiasi gauging station (g.s.), levees were built in the '70s to protect villages and towns against floods. In the upstream and middle sector of the Jiu River, several dams and reservoirs were commissioned in the late 1970s - early 1980s aiming at regulating the rivers’ flow. Due to the engineering works, the peak flood reached on October 11, 1972, of 2000 m3 /s (~70 years return period) has not been equaled until now.
In this context, this research aims to investigate the effectiveness of the structural measures taken almost 50 years ago in the lower Jiu River for flood protection, as well as their consequences on hydro-sedimentary and river channel dynamics. Examples of correlations between maximum stage-discharge reached during the low probability floods in recent decades and morphological changes in the riverbed are brought by field observations and satellite images analysis. Also, the results of the statistical analysis on hydrological data series at daily timestep indicate that, over the last 20 years, the major flood events overflowing into the floodplain were less frequent in the lower sector of Jiu River, compared to the period prior to engineering works.
If the structural measures proved to be effective for flood protection of the buildings and life-saving, there is still the question about how they impaired the natural hydro-sedimentary functioning of the river system. Satellite-based investigations and analysis on the stage-discharge relationship variation at Filiasi and Podari g.s. have shown dramatic changes in the riverbed configuration, after some flood events, especially after the deepening of the river channel.
Mots clés : floods|hydro-sedimentary dynamics|Jiu River|Romania|structural measures
A105064GM