Bringing New Life to Ancient Monuments
in Cairo, Egypt

Water began to appear within Old Cairo’s historic monuments in 1979 and over the following two decades the groundwater level rose by two meters. The floors of the most ancient buildings, located below modern ground level were heavily flooded. They continued to be immersed in standing water which had weakened the structures and prevented proper maintenance and care. Engineering and Archaeology joined forces in the design and implementation of a project which has allowed visitors access to areas which have been underwater for twenty years.

Since 2000, CCJM has designed and is managing construction of this innovative project funded by USAID and the Government of Egypt. This project is aimed at lowering the groundwater levels threatening a unique group of Islamic, Christian and Jewish monuments located around the ancient Roman fortress of Babylon in Old Cairo. The design is based on a gravity flow system employing a linear arrangement of reinforced concrete caisson shafts.

The groundwater collection shafts are 3.66m in diameter and 12-15m deep. These have precast perforations in the segments of the shaft wall, allowing a controlled amount of groundwater to drain into the shaft. The groundwater is then directed into the shaft in two ways. The first of these uses 100m of 1m wide vertical sand/gravel filters, installed by using mechanical rotary drilling equipment as a series of overlapping individual 300mm piles. These form a sand and gravel “filter wall” into which the groundwater flows and is conveyed to the shaft.

Another 500m of perforated pipes wrapped in gravel filter complete the collection of groundwater from in and around the monuments. Groundwater is ultimately conveyed out of the area through 1900m of micro-tunnels and 6 collection and 25 conveyance shafts. The filtered gravity flow minimizes movement of fine sand and silt which pumping of groundwater would cause. This in turn reduces the consequent risk of soil consolidation and differential settlement of the buildings and also eliminates the costs of a pumping station.