Identifying potential flashpoints for conflict does not require a doctorate in hydrology. In the Middle East, the world's most severely water-stressed region, more than 90 percent of usable water crosses international borders. Forget oil: The most precious resource in the region flows in the River Jordan, or resides in the aquifers that link Israel and the occupied Palestinian territories.
http://www.iht.com/articles/2006/08/.../edwatkins.php