Perhaps the single greatest threat to the preservation of Egypt’s monuments is the rising level of underground water throughout the country. Runoff from sewage and agriculture, along with overall environmental changes, is resulting in the stone of temples and tombs that were dry most of the year in ancient times becoming saturated with water seeping up from below.
This weakens the architecture, and damages wall decorations. Rising groundwater is a problem faced not only by pharaonic monuments, but by Greco-Roman, Coptic, and Islamic period structures as well. Under my direction, the Supreme Council of Antiquities is working to reduce the groundwater level around antiquities sites throughout Egypt. We have completed a USAID-funded effort to de-water Karnak and Luxor temples, and work is underway in many other places. One of our greatest recent successes has been the development of a system to prevent the Great Sphinx at Giza from getting its paws wet!
It has been clear for some time that the groundwater level at Giza is rising. Pools were forming in front of the Valley Temple of Khafre, and people were worried that this might endanger the Sphinx and its temples as well. In early 2008, the SCA, in cooperation with Cairo University’s Engineering Center for Archaeology and Environment, drilled four boreholes, each 4 inches in diameter and about 20 meters deep, into the bedrock at the base of the Sphinx. A camera lowered into each borehole allowed the engineers to examine the geological configuration of the plateau beneath the Sphinx. In addition, a small well called a piezometer was inserted into each borehole to monitor the underground water level. The investigation revealed that the water came up to about 15.6 meters above sea level, not an immediate threat to the statue, but cause for concern in the long term. I decided that it would be best to go ahead and address this threat before it could become more acute.
We investigated the possibilities for lowering the water level, and decided that the best way would be to put in a system of pumps in the area to the east of the Sphinx. A horseshoe-shaped arrangement of eight pumping stations was installed in front of the statue and its temples. Each of these stations allows a separate pump to whisk water away on a continuous basis. Every day, this system moves around 7,000 cubic meters of water, which is carried to the local drainage system.
SInce June 21, 2008, when the system was activated, the groundwater level around the base of the Sphinx, which is monitored continuously by probes in piezometers, has dropped by almost a meter. The reduction is clearly visible in front of the Valley Temple of Khafre, where the pools have almost dried up. This is great news for the Sphinx! We are currently looking into the best way to block groundwater from seeping into the area in the first place, but in the meantime, the pumping system is keeping the Sphinx and its temples safe. I am very happy with the work done by the Cairo University team, which is led by Dr. Hafez Abdel-Azim and Dr. Reda Edammek. The SCA financed the entire project, and I am proud that this all-Egyptian effort has had such excellent results.
Finally, I would like for everyone to know that the cameras inserted into the boreholes at the base of the Sphinx did not reveal any evidence at all of hidden passages or secret chambers. There is no reason to believe that such structures exist, and I hope that this will help lay to rest speculation about lost civilizations and aliens at Giza.