A typical example of cuniculi which served to drain off excess water is the network found in the sepulchral chamber of the Mengarelli tumulus in the Etruscan necropolis at Cerveteri, 35 km north of Rome. The tumulus is a sepulchre for inhumation composed of a series of chambers covered by a mound of earth. The tumulus is isolated by a ditch encircling it (Figure 24). The tumulus had a monumental aspect in the 7th century B.C. as it was built on a circular base about thirty metres in diameter cut in the natural tufo (Figure 25). Sepulchral beds are found in the subterranean chamber. One of the beds in the Mengarelli tumulus was cut by the Etruscans in order to create a cuniculus through which the water which had seeped into the chamber could be led away as there was no natural outlet for this water (Figure 26). Another cuniculus having the same function still today leads the runoff water, which has collected in the circular ditch, away from the tumulus (Figure 25).
Fig. 23 Cuniculus located at Paliano. It was excavated at the foot of a hill. The lower part of one side of this hill was cut away in 1955 (when this photograph was taken). The two branches of this cuniculus carried water from a spring. This type of spring is rare in the Roman Campagna.
A very complex network of cuniculi is visible in a locality called Ponte Terra 25 km east of Rome (Figures 27, 28). Here an earth dam had been constructed in ancient times to hold back the water. The water was first led into large tunnels excavated in the more resistant tufo of the banks to bypass the dam. At present a small quantity of water flows into the tunnel on the right. It is probable that by closing the conduit, the water level could be raised and then derived downstream by the numerous cuniculi which are still visible today. An old road connecting the towns of Tivoli and S. Vittorino still passes over the dam.
Fig. 24 Plan and cross-section of tumuli in the Etruscan necropolis at Cerveteri (A - tumulus of Colonello, B - Mengarelli tumulus, D- ditch, C - cuniculi).
Fig. 25 Etruscan tumuli photographed in Figure 24. Note the cuniculus which takes water away from the ditch.
Fig. 26 Cuniculus which takes water away from the sepulchral chamber in the Mengarelli tumulus (see Figure 24). Note that the cuniculus cuts through a sepulchral bed.
This is an example of transportation of water for uses other than for drinking. The water was, in this case, probably used for irrigation.
Fig. 27 Network of cuniculi at Ponte Terra (A - tributary of the Aniene River, E - ancient dam, D - bypass tunnels, B - old road, C - cuniculus).
Fig. 28 Ponte Terra. The water flowing into the bypass tunnel and the dam are both visible.
Another example of a cuniculus for the diversion of water is the very famous and still visible one which brought water from the Volchetta creek (the ancient Cremera) into the Fiordo creek just north of the plateau on which the ancient city of Veio was situated. The cuniculus served to balance the total water flow between the two creeks which flowed along the west and east sides of the city.
Fig. 29 Cuniculus near Formello. Two secondary branches (B, C) are connected to the main cuniculus (A). Today only the main cuniculus carries water. Its floor has been eroded by the water. The secondary branches of the cuniculus have caved in.
Fig. 30 Cuniculus near Formello, near the point where the water from the nearby valley flows into the cuniculus by the shaft. The floor of the cuniculus has been so heavily eroded that the cuniculus is visible at the top.