Hydrology and Management of Lake Kinneret Aimed at Water Quality Protection

Abstract

Long term (1969–2001) data record of hydrological parameters, nutrient and plankton in Lake Kinneret, were statistically analyzed. Trophic relations between food web compartments were quantitatively considered to evaluate ecological forces. Monthly data of inflow discharges and lake volume were used to calculate residence time values in relation to rainfall and water level. The seasonal fluctuations of the hydrological parameters, nutrients, and plankton inventories represent typical subtropical pattern: high level in winter and low in summer months. It was found that nitrogen inventories in the lake declined and the biomass of grazable phytoplankton was enhanced since early 1980’s. Dissolved phosphorus was decreased mostly in summer months when the lake is nutrient limited, as a result of phytoplankton uptake. Zooplankton was declined until 1993 and increased later. The most abundant zooplanktivorous fish, Lavnun (Bleak, Acanthobrama spp.) densities increased during 1993–95 and subsidized fishery caused zooplankton enhancement and consequently suppression of primary production. Lavnun removal might be efficient to enhance zooplankton grazing capacity and algal suppression if external phosphorus loads from the drainage basin are reduced. The major effect on nutrient inventories in the lake is due to inputs from the drainage basin.Consequently, management implications aimed at lake water quality protection should be mostly directed towards nutrient removal in the drainage basin and loads reduction by pumping water for supply. The water storage capacity in the lake is significant to ensure maximum utilization.