The water level in the Kinneret, Israel's largest reservoir and freshwater source, dropped by six whole centimeters over the Passover holiday, the Water Authority announced Sunday. In July, the level is expected to drop below the "Black Line," the absolute lowest limit below which no more water can be pumped from the lake. Experts predict that Israel will experience a drought of potentially unprecedented proportions because of a relatively dry winter which follows several dry years. The Water Authority marks three threshold lines on the lake: The Upper Red Line, the Lower Red Line and the Black Line. The Upper Red Line is 208.9 meters below sea level; when the lake reaches the upper line the Deganya Dam is opened to prevent the lake from overflowing; the Lower Red Line is the levels at which the water in the lake drop to the extent that the concentration of pollutants in it rises to undesirable levels and pumping more water from the lake is prohibited. The Black Line is met when water levels drop to a point so low that the openings of the pumps are exposed and further pumping becomes simply impossible. The Water Authority's main target in its effort to curb a water crisis has focused on attempts to reduce the usage of water for agriculture, which in recent decades had lost its reputation as Israel's economic mainstay and has come to be seen as a relatively low-profit industry when compared with other fields where Israel has come to excel, such as hi-tech and medical industries.