The monuments of ancient Egypt may have stood for thousands of years in the desert sands, but now they face a new threat -- from rising groundwater.

Ayman Ahmed of the University of Sohag, Egypt, is working with Graham Fogg, professor of hydrology at the University of California, Davis, to study the problem and find ways to solve it.

Preliminary findings by Ahmed and Fogg indicate that farming, urbanization and residential housing near the temples are causing water tables to rise. When the water table rises, the groundwater comes closer to the foundations, columns and walls of the antiquities, causing structural damage. Water and salts weaken the sandstone structures.

"Probably the most dangerous factors affecting the pharaonic monuments are urbanization and agricultural development," Ahmed said. Damage to the monuments has worsened in the years since completion of the Aswan dam, allowing year-round irrigation of crops instead of seasonal flooding, said Fogg.

Ahmed and Fogg are using data from sites including the temples at Luxor and Karnak to build a computer model of how groundwater moves under the monuments. They hope to find ways to prevent or reduce the damage.

Ahmed approached Fogg's group after concluding that UC Davis had one of the strongest hydrology programs in the world.

"It's a fascinating problem," said Fogg.