Lake Bathymetry and Bottom Morphology

Abstract

The bathymetry and morphology of Lake Kinneret is influenced by its complex tectonic structure and by high annual sedimentation (~ 100,000 t year⁻¹ for the past 50 years). In general, the lake floor has an asymmetric shape with mild bathymetry at its western part and steep bathymetry at the eastern part. Based on a new multibeam bathymetric mapping conducted in 2008, the total surface area of the lake is 168.7 km² (at water level − 209 m a.m.s.l.) with a maximum depth of 41.7 m (− 253.7 m). The water storage capacity ranges from 4,325 to 3,661 × 10⁶ m³ at water levels of − 209 to − 214 m, respectively. A comparison of the 2008 multibeam bathymetry to echosounder bathymetry of 1986/1987 revealed dramatic changes in the lake bathymetry. The southern basin became significantly shallower; sediment accumulation over the 21 years between the two surveys may have accounted for up to 2 m rise in the lake floor at some places, estimated to represent ~ 10 × 10⁶ t of sediment. The northern basin however does not show evidence for massive sedimentation (< 0.5 m), whereas judging by the − 214 m (a.m.s.l.) contour, the littoral perimeter had been eroded significantly. The existence of bathymetric lineaments on the lake floor indicates recent and active processes in the lake. Two main lineament trends were found: a N–S trend, mainly on the eastern and southwestern borders of the lake, probably associated with active traces of the Dead Sea fault system and a NW–SE trend, which is probably the continuation of the normal faults of the eastern Galilee fault system. The major morpholineament found in the 2008 bathymetry is located in the northwestern deeper parts of the lake (− 232 to − 242 m) and is N–S oriented. The epicenters of the October 2013 earthquakes are found in the vicinity of this lineament.