Morphometrical and Dynamical Features of the South Dobrogea Lakes, Romania

This paper presents some morphometrical and dynamical features of the South Dobrogea lakes based on the bathymetric data between 2010-2011. The analyze includes the lakes on the Black Sea shore (Siutghiol, Limanu and Tatlageac) and on the right side of the Danube River (Bugeac, Oltina, Mârleanu, Domneasca). The Siutghiol Lake is the deepest one with 7.82 m and has the highest volume (69.69 mil. m3). The Domneasca Lake has the lowest maximum depth (2 m) and the smallest area (0.49 km2).The wind is a main factor which causes the water dynamic, and determines the resuspension of the sediments by the wave action. In order to estimate the bottom dynamic conditions, the form factor (Vd), the erosion and transport areas (ET) of fine sediments and the fine sediments accumulation areas (A0) were determined based on the morphometrical features: lakes area (A, in km2), the mean depth (Dm, in m) and the maximum depth (Dmax, in m).The study shows that the areas of accumulation prevail in the Tatlageac, Siutghiol and Domneasca lakes (62.64-69.36%) and the erosion and transport areas prevail in the Bugeac, Oltina, Mârleanu and Lakes (76.67-99%). The dynamic ratio (the ratio between the area's square root and the mean depth) ranges between 4.18 (Oltina Lake) and 0.40 (Domneasca Lake). The relation between the lake form and the bottom dynamic conditions is highlighted by the form factor which ranges between 0.78 (Limanu Lake) and 1.83 (Domneasca Lake). Our estimation of the erosion, transport and accumulation areas of the fine sediments could be useful for improving the management of the lakes, especially for the lakes that are used for fish production, imposing some structural and nonstructural measures.