Derivation of Design Rainfall Temporal Patterns in Australia's Gold Coast Region

Design of water infrastructures requires estimation of design flow which is the runoff that an infrastructure can handle safely. For estimation of this design flow, rainfallrunoff modelling is widely adopted. Temporal pattern (the distribution of rainfall depths over sub-storm durations) is considered to be one of the most critical input variables in the rainfall-runoff modelling. Design temporal pattern can affect the design runoff hydrograph significantly. The currently recommended design rainfall temporal patterns in Australia were derived in 1987 using the data before 1986. Due to climate change, it is expected that the design rainfall characteristics have been changed, thus making the application of currently recommended design rainfall temporal patterns in Australia questionable. This paper examines data from 22 pluviograph stations in the Gold Coast region to assess the time-trend of temporal patterns in this region. This considers design rainfall temporal patterns from 10 minutes to 120 hours storm durations. It has been found that there are significant changes in temporal patterns in recent years which may have notable implication in the design of water infrastructures in the study region. The results indicate that the design rainfall temporal patterns in Australia needs up-gradation to reflect the effects of current climate change to make the water infrastructures safer.