The amount of rainwater reaching Lake Kinneret and groundwater reservoirs in Israel has decreased by 11 percent in the last two decades, according to a recent report by the Israel Water Authority. According to the report, which studied the natural water resources between the Mediterranean Sea and the Jordan River, the decrease in water reaching the Sea of Galilee was even higher, at 13 percent. The report also foresees a further decrease in natural water resources due to climate change.

Staff of the Israel Hydrological Service at the Water Authority carried out a comprehensive study of yearly rainwater in Israel and the overall replenishment volume of water reservoirs after rains. The report focused particularly on the Kinneret - the most important surface water resource in Israel - and aquifers and groundwater reservoirs in various areas, and compared their situation with a past study between 1973 and 1992. The current study encompassed 1992 to 2009.

The reported decrease of 11 percent is considered dramatic in such a relatively short period. The yearly average which reached the Kinneret between 1950-1980 was 505 million cubic meters. Between 1980- 2010 it dropped to 385 mcm, and according to an ensemble of regional climate models, a further decrease of 15 percent is expected in the next two decades.

The report also focused on the Eastern Mountain basin, which is an important source of water for Israel and the Palestinians´ main water source. The data shows the annual replenishment volume has decreased from 173 mcm a year to 138 mcm.

The report states, "This decrease, together with an increase of groundwater pumping, has depleted the aquifer storage, and in specific areas some pumping wells have gone dry."

This data may have serious implications for the distribution of water between Israel and the Palestinians, who claim they should receive more water from this basin. The Water Authority claims that more pumping from the aquifer could further harm it.

In the two main basins serving Israeli water needs - the Coast aquifer and the Western Mountain aquifer - a decrease in replenishment was also recorded.

The report is especially concerned with the role of the coastal aquifer situated in Gaza. The Water Authority cannot study its situation, but according to a report published this week by the World Bank - based on data from the Palestinian Water Authority - there is a marked decrease in the water level of the aquifer, leading to seawater intrusion. It is also being polluted by various other sources, including the sewage system. The report adds that up to 95 percent of the wells drilled in Gaza do not meet the standards of the World Health Organization.

The report supports the position of the Israel Water Authority, which insists that Israel must continue to develop desalination systems. These already account for more than 300 mcm a year and should produce double that amount within a decade.

The Palestinians in Gaza have also recently begun building desalination systems in order to deal with the worsening water crisis in Gaza. (© Copyright 2012 Ha´aretz 03/18/12)