The supply of the public lacus of Pompeii, estimated from the discharge of their overflow channels

Abstract The term lacus generally identified the public fountains in main streets of ancient Roman towns, providing for population daily water demand. simplest consisted a stone basin and spout stone, concealing one or two supply pipes. 35 street this type have been surveyed Pompeii, to gather information on their its variation time. A new method was devised calculating discharge through overflow channel each , value taken as an estimate supplied fountain. internal cross-section width measured at four elevations, profile reconstructed based these data. Three levels 1 cm, half height entire cross section height, were considered channel’s inlet, obtaining corresponding discharge. values obtained, ranging from 0.03 2.9 l/s, checked against trajectory fountain jet, making sure that it remained within length. For 28 average found be 0.08 l/s when lowest level, 0.43 intermediate level 1.18 full inlet. time residence water, draw basin, estimated between 11 min 3 h. An demand all town compared with capacity aqueduct entering Porta Vesuvio: could contemporaneously minimum discharges.