Reconstruction of a manhole/settling tank along the conduit between San Sebastianello and the Piazza del Popolo, which is described in Archivio di Stato di Roma, Notai del Tribunale delle Acque e Strade, b.6, prot. II, fols.269r-271r. Drawing by Chiara Bariviera (Copyright 2017; used with kind permission). For a discussion of this structure, see Pamela O. Long, Engineering the Eternal City, p.86.
