A series of small canals were built behind and in front of the Sant’Eulalia area colonnade, to drain rainwater and create a green space (figs. 1-4).

Fig. 1 - Small canal in front of the portico (photo by Unicity S.p.A.).

Fig. 2 - Small canal in front of the portico (photo by Unicity S.p.A.).

Fig. 3 - Canal adjacent to the church substructures (photo by Unicity S.p.A.).

The portico is set on a high base covered with plaster, limestone and marble slabs, with a lowered floor in front of it. Canals of various sizes were built in this space: most held green areas, like flowerbeds (figs. 2-4); while one of the minor canals poured its influx into a cistern (fig. 4), for the population's daily needs.

Fig. 4 - Transversal canal carrying water to the cistern (photo by Unicity S.p.A.).

You can see an ample water channel behind the portico's back wall. You can still see the waterproofing of the portico's rear structure, with a thick layer of Opus signinum and a row of hamatae tiles on it, covering it.