The most immediate threat to preserving the ruins of Babylon, the site of one of the Seven Wonders of the Ancient World, is water soaking the ground and undermining what is left in present-day Iraq of a great city from the time of King Nebuchadnezzar II.

It is also one of the oldest threats. The king himself faced water problems 2,600 years ago. Neglect, reckless reconstruction and wartime looting have also taken their toll in recent times, but archaeologists and experts in the preservation of cultural relics say nothing substantial should be done to correct that until the water problem is brought under control.

A current study, known as the Future of Babylon project, documents the damage from water mainly associated with the Euphrates River and irrigation systems nearby. The ground is saturated just below the surface at sites of the Ishtar Gate and the long-gone Hanging Gardens, one of the seven wonders. Bricks are crumbling, temples collapsing. The Tower of Babel, long since reduced to rubble, is surrounded by standing water.

Leaders of the international project, describing their findings in interviews and at a meeting this month in New York, said that any plan for reclaiming Babylon as a tourist attraction and a place for archaeological research must include water control as “the highest priority.”