Page 49 - Urban water supply handbook

URBAN WATER INFRASTRUCTURE: A HISTORICAL PERSPECTIVE

1.48 HISTORY, PLANNING, OUTSOURCING

FIGURE 1.34 Aqueduct bridge of the Sirince system from Pirango to Ephesus. (Photo by
Koksal B. Celik)

1.3.6 Siphons
Siphons were briefly mentioned in Sec. 1.2.2, and the parallel siphons near
Laodicea in Turkey were shown in Fig. 1.10. Siphons were built throughout the
Roman Empire, being numerous in Gaul and relatively rare in Rome (Hodge,
1992). Many more were built in Roman times than in Greek times. The best-pre-
served and largest examples of siphons are found in Lyon. Most siphons were V-
or U-shaped for valley crossings. In some situations two or three siphons were
used in series. An example of a double siphon is at Les Tourillons on the
Craponne, Lyon. A triple siphon was built at Aspendos with two open tanks sep-
arating them at the top of the two (north and south) towers. Figure 1.39 shows a
general view of the wide area without a true valley, with the south tower in the
foreground and the north tower in the distance.

1.4 ROMAN WATER SUPPLY:
URBAN DISTRIBUTION SYSTEMS

A diagram of a simple Roman urban distribution system (as based on the Pompeii
system) is shown in Fig. 1.40. The main aqueduct ends at the main castellum, or
castellum divisorium. The castellum divisorium is a junction where the main aque-
duct ends and the urban distribution system begins. A lead pipe or smaller aqueduct

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