Mixing dynamics of stream water into Lake Kinneret through a short-period flow release test

The water authority of Israel has decided to create an unnatural flow starting at a point in the Tzalmon stream into Lake Kinneret (Sea of Galilee) 4 km upstream as a way to manage the lake water level. The national water company “Mekorot” use the existing national water carrier to take water from the desalination plants next to the Mediterranean Sea and transfer it to the Tzalmon river where the water will naturally flow within the stream into the lake. A test flow was conducted at changing discharge rates of 3,100, 4,500, and 6,000 m³ hour^-1 for three hours for each flow rate for two days to examine the new flow system that leads desalinated water into the Tzalmon stream. Nevertheless, the test flow was a great opportunity to study the Tzalmon flow's ability to transport particles, nutrients, and bacteria as well as study their distribution dynamics in the lake. Fifteen temperature sensors were deployed in the Tzalmon river outlet to the lake to capture the mixing dynamics with the lake water during the test flow. During the flow release, profiles of temperature, electrical conductivity (EC), dissolved oxygen (DO), and pH were conducted along the flow path of the water into the lake using a boat in 5 locations. In addition, the boat sampled the water for total dissolved solids (TSS), nutrients, bacteria concentration, and general chemistry in those 5 locations in the river outlet. Along the river, six temperature sensors were deployed in and out of the water in three locations to understand the temperature change along the flow path from the discharging point to the lake. Furthermore, water samples from those 3 locations along the flow path were taken and analyzed to the above-mentioned parameters at each flow rate discharge. The results highlight the ability of the river flow to carry those parameters at different flow velocities along with their distribution dynamics in the lake water. Furthermore, the water reached the lake only at the end of the second flow period and during the third flow period due to losing conditions along the flow path. Therefore, there were only two occasions of river water mixing in the lake, and this mixing dynamic was studied and will be presented at the session. This new water discharge into an ephemeral river will start in the next few years and will change the river area ecosystem and will bring newly dissolved and solid materials into the lake. This test is the first examination of the system in which the constant flow release will potentially influence the lake ecosystem and the flow regime in the lake.