EL-NABIH CISTERN: the historical and architectural study, and the initial excavations

Pre-excavation studies
 
Laurent Borel & Chrystelle March, architects
with Samuel Desoutter, archaeologist
February 2007

Architecture of the structure

The Nabih cistern is situated on Sultan Hussein Street (formerly rue d’Allemagne), in the south-east corner of Nubar Pasha gardens, adjacent to a section of the Arab city wall that was destroyed at the beginning of the 20th century.
The structure is entirely buried, approximately cubic in form (13 x 11.5 x 12m) and with a volume of roughly 1000m3 (fig. 2). The walls of the reservoir, nearly 1.2m thick, are composed of small stone blocks. In order to resist the pressure of the earth, the stability of the structure is maintained by a system of cross bracing composed of four rows of four columns with interconnecting arches, all on three levels.
Fig. 2 : Plan and section of El-Nabih cistern
Drawing : C. Shaalan, Y. Guyard, I. Hairy, E. Hardy © CEAlex. CGD: L. Borel, Ch. March © CEAlex.
All of the upright supports are made from re-used architectural elements taken from earlier constructions. The masonry structures are covered with a hydraulic plaster to ensure the waterproofing of the reservoir. The cistern has two systems of roofing. In the northern part there is groin vaulting, while the southern part is supported by barrel vaults. The architectural study has demonstrated that the cistern was originally covered solely by groin vaults, since the walls of the southern section of the reservoir still bear traces of such (fig. 3).
Fig. 3 : Schematic representation of the cistern and its roofing before the excavation
3D modelling : L. Borel © CEAlex.

How it worked

The largest opening in the roof of the cistern is situated above the central span of braces. This was the main access for drawing water and would have once featured a mechanical device for lifting the bucket or buckets. Two other, smaller holes are situated in the south-west corner of the reservoir. The may have been pierced at another time to allow water to be drawn from some informal construction that was installed at a later period directly over the cistern.
In the north-east corner, a semi-circular shaft descends into the reservoir. This opening was the sole human access point of the structure and small cavities on the shaft walls served as foot-holes (fig. 4). On the location plan of the cistern found in the “Kamil Files” there are structures, now missing, that are informative as to the cistern’s water supply. To the south-east of the reservoir, the engineer notes a channel, two retaining walls, a basin and he signals the emplacement of a saqqia (water wheel). The water lifted from underground must have been channelled to the southern edge of the cistern. Indeed, it is here that one can see the remains of piping in the inside of the reservoir.
Fig. 4 : Old photograph showing a saqqia supplying an aqueduct near the Eastern Harbour. The Cairo Postcard Trust. Private collection L. Borel.

The cistern in the urban context

We do not yet know the place of El-Nabih cistern within the urban environment. Only the study of other big public cisterns, such as that of Gharaba, can perhaps shed light on this subject. It is possible, for example, that the upper part of the reservoir was above ground level. Such a position would advertise its presence and avoid the contamination of the water of the cistern by wastewater on street level.
This lay out, however, is still merely hypothetical. It is altogether possible that El-Nabih cistern, while being a public water storage facility, was designed for a more restricted use and, as a consequence, access to it and its position in the urban context were different. Examination of the “Kamil Files” reveals that the cistern on the north side was in fact attached to a “magasin des artilleries” that was itself built against the interior façade of the Arab city wall. It could be that the cistern was part of a specific installation and was exclusively connected to the defensive system of the town (fig. 5).
Fig. 5 : Engraving of the Arab city wall, fortified by Gallice Bey, near the Porte de Rosette. The Illustrated London News, Aug. 5, 1882, p. 132. Archives © CEAlex

Dating the cistern

At this point in time we have no archaeological data that would allow us to date the construction of the cistern with precision. Cisterns of this type (Type V: large capacity, cross bracing on several levels composed of re-used architectural elements) have been identified by the authors of previous studies simply as large public cisterns of the medieval period.

Such a dating is supported by an examination of the re-used architectural elements, of which the most recent is a late Corinthian capital from the second half of the 6th century AD. This information makes it reasonable to suppose that construction was after this date (fig. 6).
Lastly, the presence of the Arab city wall just some metres from the cistern might suggest that its construction was contemporaneous with this section of the fortifications, built under Ibn Touloun, the sultan of Egypt in the 9th century. However, the mere proximity of the cistern cannot be sufficient argument for its dating given the present state of our knowledge.
Fig. 6 : The Corinthian capital from the second half of the 6th century AD.
Photos: L. Borel © CEAlex. Drawing: L. Borel, E. Combes, C. Pigounaki © CEAlex
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