Investigation of drainage systems in ancient theaters

In this work, the operation of the rainwater drainage systems in the ancient theaters is studied and the design of the euripus, (the pipeline around the orchestra which collects rainwater) was evaluated. In particular, 15 ancient theaters were examined and based on their geometric characteristics and the IDF (intensity-Duration-Frequency) curves of neighboring rain gauges, the following magnitudes were estimated: (a) the drainage capacity of the euripus, (b) the consecration time, (c) the critical rainfall intensity and (d) the return period to which the critical rainfall intensity for the consecration time corresponds. Based on the analysis, the drainage capacities of the euripus range from 50-1600 l / s and the consecration times of the cavea ranges from 4 to 8 min. Flood protection was satisfactory in all cases. Only in two theaters, the return period of rainfall intensity that overflowed euripus was estimated at less than 100 years. Finally, in many cases the euripus was much larger than needed to ensure the flood protection of the orchestra. In these cases the way of euripus construction may be related to other architectural or aesthetic criteria. Future must include: (a) more detailed mapping of ancient theaters, (b) application of the methodology in more theaters, (c) recording of the characteristics of all the hydraulic works of each theater and (d) creation of a geographical database of ancient theaters.