Author(s): H. Chanson
Linked Author(s): Hubert Chanson
Keywords: Dropshaft; Roman aqueduct; Energy dissipation; Flow aeration; Engineering heritage; History of hydraulics
Abstract: In Roman aqueducts, series of vertical dropshafts (i. e. dropshaft cascade) were used to dissipate the kinetic energy o the flow. Up to recently, it was thought that the dropshafts acted also as sediment traps. A new re-analysis of Roman dropshaft hydraulics was conducted with physical model tests performed at the University of Queensland. The results demonstrate that the vertical dropshafts could be very efficient energy dissipators and re-oxygenation structures, under appropriate flow conditions. The optimum operation of dropshaft is discussed and an analytical model is developed to predict these conditions. In addition, the performances of aqueduct dropshafts are compared with modern dropshaft designs. Dropshaft cascades were used successfully for centuries. The Roman engineers built sound dropshaft designs which were most efficient dissipators and aerators.
Year: 1999