The mechanism of Lake Kinneret salinization as a linear reservoir Alon Rimmer * Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research Ltd, P.O. Box 447, Migdal 14950, Israel Received 11 March 2002; accepted 23 June 2003 Abstract The salinity of Lake Kinneret, Israel, is significantly higher than the salinity of the water from surface streams that flow to the lake. The relatively high salinity is a result of the activity of saline springs located at the bottom of the lake. The purpose of this work is to establish a general model for the salinization mechanism of Lake Kinneret. The model is based on the main components of the annual water and solute balance. Changes in time of the solute mass of the lake were described as a differential equation of a linear reservoir on an annual time scale. The model assumes that under any long-term operation policy of the lake, the components of the annual solute and water balance stay nearly constant in time. The model was tested for both steady-state conditions, and during changes in time, against measured lake salinity over the years 1968–2000. It was found that the major changes of lake salinity throughout the years were described well, despite the variety of rainfall amounts. Predictions of the expected lake salinity changes were proposed for the cases of controlled increase or decrease of saline springs discharge to the lake; for the changes of water quantity allowed to flow into or pumped out of the lake; and for various initial salinities. Predictions agree well with previous predictions made by statistical models. q 2003 Published by Elsevier B.V. Keywords: Lake salinity; Solute mass balance; Linear reservoir; Lake Kinneret 1. Introduction Lake Kinneret is a small lake in the central part of the Jordan Rift Valley (Northern Israel). The average area of the lake surface is 166 km 2 and the average volume is 4020 Mm 3 . The lake drains a watershed of 2730 km 2 . The salinity of Lake Kinneret (measured in ppm Cl 2 ) is significantly higher than the salinity of the water from surface streams that flow to the lake. The relatively high salinity of the lake is a result of the activity of saline springs located near the shore- line, and offshore springs at the bottom of the lake. The history of Lake Kinneret salinity is documen- ted since, the beginning of the 20th century. The first salinity measurement was reported by the British researcher Annandale in 1913 (Dalinsky, 1969), who found a concentration of 239 ppm Cl 2 . Dalinsky (1969) indicated that the method of measurement was similar to the method in the 1960s, and therefore there is no technical reason to dispute the reliability of this measurement. The British Mandate Hydrological Service (The Israeli Hydrological Service, IHS since, 1948) took the next registered measurement, 300 ppm Cl 2 , in 1934. At least seven lake salinity measurements were reported between the years 1945 0022-1694/$ - see front matter q 2003 Published by Elsevier B.V. doi:10.1016/S0022-1694(03)00238-5 Journal of Hydrology xx (2003) xxx–xxx www.elsevier.com/locate/jhydrol * Tel.: þ972-4-6721444; fax: þ972-4-6724627. E-mail address: alon@ocean.org.il (A. Rimmer). ARTICLE IN PRESS