The response of the sedimentological regime in Lake Kinneret to lower lake levels

The surface level of Lake Kinneret is regulated to remain between -209 m and -213 m msl. During the stratified period, soluble reactive phosphorus (SRP), ammonium (NH4+) and dissolved sulphide (H2S) accumulate in the hypolimnion. The concentration of these solutes, which are direct and indirect products of the decomposition of organic matter, increase considerably in summers with lower lake levels. A numerical model describing depth-averaged hypolimnion and epilimnion current velocities for high and low lake levels was adapted for Lake Kinneret. Simulated hypolimnetic currents were shown to be stronger for low lake levels as a result of the fact that low lake levels are characterized by a thinner hypolimnion while the thickness of the epilimnion remains unchanged. We suggest that the stronger hypolimnetic currents have the following consequences: 1. turbulence is induced, 2. the enhanced turbulence results in higher resuspension, 3. because SO4= is available to bacteria on resuspended particles, mineralization rates are enhanced, and 4. focusing of fine sediments and associated organic matter to the pelagic zone is enhanced.