Title: Flood Estimation in Urban Catchments with RORB – Monte Carlo Simulation – Use of Local Historical Pluviographic Data
Australian Rainfall and Runoff (ARR87) (I.E. Aust 1987) provides a number of design rainfall temporal patterns. While, based on historical pluviographic rainfall data, the small number of zones defined across Australia provides limited information on local rainfall patterns at a specific location. Recent enhancements in RORB provide for the sampling of rainfall temporal patterns from long term pluviographic records. This paper applies RORB to several urban catchments in Melbourne and Ballarat. Long term local pluviographic records are sampled to determine design rainfall temporal patterns. The study catchments contain significant retarding basins and drainage-related infrastructure. The performance of this infrastructure is examined for both the ARR87 and locally sampled design temporal patterns. In particular, the design flood hydrograph volumes are compared for the two sets of design rainfall. The paper provides broad conclusions on the role of temporal patterns in design flood estimation, in particular for the sizing of retarding basins and other drainage related infrastructure.