About 40 km southeast of Cairo, close to the town of Helwan, lie the ruins of the Sadd-el-Kafara, a large embankment dam built approximately 3,700 years ago. Its primary purpose was to contain the waters stemming from sudden storms and heavy floods. It also served the dual function of providing water to laborers and animals involved in quarrying stone and marble for the construction of the pyramids and temples in the vicinity. Unfortunately, the dam was destroyed by a flood before it could be completed. Rediscovered less than 140 years ago, today it is recognized as the oldest dam of such size in the world.
Photo credit: Matthieu Götz
The dam is situated in the Wadi Garawi, one of the numerous wadis in the desert east of the Nile Valley. The dam is located at the narrowest point of the Garawi ravine at a point where the valley narrows to about 100 meters wide. The dam was originally 113 meters long and 14 meters wide, with a base width of 98 meters and crest width of 56 meters. The dam's core was 32 meters wide and would have consisted of 60,000 tons of earth and rock-fill. If completed, the dam would have stored between 465,000 to 625,000 cubic meters of water. Today, only the ends of the dam on both sides of the wadi stand. The central section was washed away leaving a gap of roughly 50 to 60 meters wide.
The dam’s location in the Wadi Garawi is somewhat of a curiosity. It has been conjectured that the dam was built not for irrigation but rather to manage the sudden flash floods common in the narrow valleys. There is no evidence of cultivated land around the dam which may require water for farming. Also, the absence of spillways in the dam indicates that the reservoir was not built for irrigation. Yet, the absence of important settlements in the vicinity raises question among various authors about what precisely the dam was intended to protect. The commonly accepted belief is that the Sadd el-Kafara dam was constructed to protect the lower Wadi Garawi against floods and to shield the area where settlements likely existed at the mouth of the wadi in the Nile Valley.
Photo credit: Matthieu Götz
The dam's downstream face shows signs of erosion, leading to the belief that a flood ultimately destroyed it. Moreover, the absence of a spillway and any indications of a trench or tunnel to redirect water around the construction site contributed to this vulnerability. While the construction on the upstream side was largely finished, the downstream section remained significantly underdeveloped. The dam's crest sloped inward, potentially intended by the engineers as a spillway. However, as the top of the dam was not flattened, it lacked protection from floodwaters that could overtop the crest.
The collapse of the dam probably caused a catastrophic flood in the lower wadi. The impression left by the disaster must have been so terrible that it discouraged early Egyptians from constructing other dams of the same composite section for nearly eight centuries.
The dam was discovered in 1885 by the German archaeologist Georg Schweinfurth. The missing mid section and the resulting exposed cross-section allowed archeologists to study the dam’s construction. The sides of the dam are said to be in “excellent condition”.
Photo credit: Matthieu Götz
Photo credit: Matthieu Götz
# Sadd Al-Kafara dam, Hydria Virtual Museum
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