Covered reservoirs in Constantinople and Paris but not in North America

Or il est bien évident, pour ceux qui connaissent le climat de cette contrée, qui connaissent surtout le vent violent qui soufflé souvent à Nîmes, vent qui soulève des flots de poussière et même de gravier, il est bien évident, disons-nous, que les constructeurs du castellum n’hésitèrent pas longtemps pour savoir s’ils fermeraient (sic)de toute par leur castellum. –Les eaux des fontaines d’Airan et d’Eure arrivaient dans l’ancienne cité par une canalisation fermée; or, pour conserver à ces eaux toute leur limpidité, il fallut de toute nécessité fermer le

castellum.173

Why weren’t Montreal’s reservoirs covered in the first place? Before reservoirs, water was collected and stored in covered cisterns and tanks. Even wells and sources traditionally have some form of roof. Yet open reservoirs were built in many large North American cities, from New York to Pittsburgh to Toronto. In 1997 there were still an estimated three hundred open reservoirs out of 10 000 water storage facilities in the USA.174 With the development of large-scaled reservoirs this common sense covering was left aside, presumably for economic and technical reasons, although perhaps also because in the less densely populated, and not yet very industrial cities of North America, factors like environmental pollution were not yet as critical.

Throughout history protected or covered water storage was inevitably a strategic factor for cities that developed in a hot climate, or through years of war and siege. There are quite ancient models of covered reservoirs. Constantinople built covered reservoirs as early as the 6th century.175 The vaulted masonry roofs supported on closely spaced columns of these monumental structures established a constructive form that varied little until the introduction of reinforced concrete in the 20th century. (Figure 3.1)

173 _{Ernest Bosc, Dictionnaire raisonné d’architecture et des sciences qui s’y rattachent, (Paris:}

Librairie de Firmin-Didot et Cie., 1877), 413. An explanation of why the Romans would have covered their water towers (castellum) as a matter of common sense.

174 _{EPA, 1999, 1-3; It would be interesting to have a geographic breakdown of the areas where}

open reservoirs were built, to evaluate the importance of the climate factor. Compare for instance with the same period of early urban development in Sydney (Australia) where large scaled covered reservoirs were built. Aird, The Water Supply… of Sydney, (1961), 64-66.

175 _{Stéphane Yerasimos and Pierre Pinon, “Istanbul: Aqueducts, Cisterns, Fountains and Dams,”} Rassegna (Aqueducts), 57:1 (March 1994): 54-59.

Figure 3.1 The reservoir of the Atmidan Hippodrome, Constantinople

(Source: Cornelius Loos, reproduced in Rassegna (Aqueducts), 57:1 (March 1994): 58)

Figure 3.2 Montsouris reservoir under construction, Paris, 1874

(Source: Reproduced in Laure Beaumont-Maillet, L’eau à Paris (Paris: Hazan, 1991), 190)

Figure 3.3 Montmartre multi-storey reservoir, section, Paris, completed ca.1890

Bottom two levels with river water, top level with spring water

(Source: Leveson Francis Vernon-Harcourt, Sanitary Engineering with Respect to Water-Supply and

By the 19th century, monumental covered reservoirs were also being built within denser industrialised cities like Paris. Water was brough by gravity from a variety of uphill sources to the multi-storey Menilmontant and Montsouris covered reservoirs built in 1863-65 and 1869-74.176 (Figure 3.2) The reasons given for covering the water are both related to the effect of sunshine and the fact the water in these reservoirs came from spring fed rivers: to protect such water, considered particularly susceptible to vegetable growth that gives water a sour taste, and to keep the water at a cool temperature. The subdivision of the reservoir in horizontal levels was thereby also possible, something particular to the Paris situation. Spring water for domestic use was stored on top and river water for firefighting and street cleaning on bottom. (Figure 3.3)

An earlier proposal from 1853 that was not built is also worth noting in relation to what happened in Montreal: it was suggested that Seine River water be pumped into a series of reservoirs excavated in the hill of Montmartre whence it could be distributed by gravity throughout the city. But while some critics were concerned about the quality of the river’s water, Hausmann argued against this system because it would depend on pumps to raise the water, and the gypsum soil of the hill would affect the quality of the water.177

Comparison with these Paris models is instructive as regards to both the water and topography. In comparison with an older bigger city like Paris, Montreal’s situation was quite different. In the 19th century, the reservoirs located on Mount Royal were not really in the city, and the St-Lawrence River was only considered polluted along its shores. Montreal’s water was from a surface source exposed to the elements and the atmosphere the length of the river’s course, and delivered by an open conduit that cut through part of the city. No concern was ever expressed about the geological composition of Mount Royal, in which the reservoirs were excavated. In fact, the mountain’s sedimentary and igneous rock was considered relatively impervious and thought to contribute positive

176 _{Beaumont-Maillet, L’eau à Paris, (1991), 246.}

177 _{Beaumont-Maillet, L’eau à Paris, (1991), 168-169. There continued to be many proponents of}

the Seine as the best source for the city, and it does along with water from the Marne continue to provide ca. 40% of the city’s supply, but treated river water is still secondary in value to the spring waters. Beaumont-Maillet, L’eau à Paris, (1991), 238-241

minerals to both underground and surface waters.178 On the other hand, although similar concerns about dependence on pumps were expressed, the possibility of using waterpower to raise the water instead of coal-driven steam made the kind of large-scale gravity-supplied systems of Paris less interesting in Montreal. Finally, no distinction was ever made in storing cleaner drinking water from water for firefighting.