Falling water level raises waves of concern over Kinneret bacteria
The sharp drop in the water line of Lake Kinneret could lead to fecal bacteria penetrating the pumps to the National Water Carrier and change the lake's ecosystem, according to a report released this week by by a government research agency.
The report, by the Israel Oceanographic and Limnological Research institute, notes that the bacteria is suspended in the increasingly shallow water around the pumps and could penetrate the system. Algae could also enter the system, resulting in the development of other bacteria. The presence of toxic materials from algae is a risk that affects the entire lake, according to the report.
So far, none of these risks have affected water reaching consumers.
The ongoing problem of salinization, according to the report, will worsen if there is a further drop in the quantity of fresh water from springs and streams feeding the lake. The report notes that the amount of water entering the lake dropped from 550 million cubic meters per year 50 years ago to the current 440 million cubic meters. If the salinization trend continues, the lake water will become 60 percent more saline over the next 30 years.
When this water is used for irrigation, it sinks into the soil and eventually reaches the water table, which will mean increased salinization of the water table in other areas of the country irrigated by the National Watr Carrier. A related problem is that on a number of occasions the channel that draws saline water out of the lake could not be used for this purpose after it filled with sewage water from Tiberias.
In the past, the water level would naturally fluctuate by less than 1.5 meters per year. However in recent decades the range has become as great as six meters because of the pumping from the lake. The institute's Dr. Tamar Zohari says it is the fluctuations, rather than the actual drop in the level, that alters the lake's ecosystem.
Snails that thrive in the shallows are dying in droves due to the drop in the water level.
In past years the Kinneret saw a major drop in the numbers of fish, also a result of fluctuations of the lake's level - the quantities of St. Peter's fish (tilapia) were at an all-time low because the drop in the lake's level allowed fishermen to pull in larger catches, even from the shoreline.
Among the report's recommendations is to reduce the fluctuations in the water level and take steps to prevent the penetration of fecal bacteria to the pumping system.
The report also advises authorities to re-examine the feasibility of drilling for water in the Hula Valley north of the lake, which would reduce the amount of water flowing to the lake and to persuade farmers to raise crops that use less water. The report further recommends prohibiting the passage of vehicles in areas that are currently dry to avoid damage to the ground in those areas, actually part of the lake bed, which would prevent the rehabilitation of the lake bed when those areas are again covered with water.
Last week, the head of the Water Authority, Professor Uri Shani, pledged to work to prevent the level of the lake from dropping to the low point it fell to seven years ago in an effort to prevent damage to water quality.