Design streamflow estimation for ungauged catchments in Victoria : uncertainty analysis using boot strapping

Design flood estimation in ungauged catchments is often required by hydrologists. The chapter on regional flood estimation procedure in the national guideline on design flow estimation in Australia know as Australian Rainfall and runoff (ARR) has not been upgraded during the last 20 years. This paper presents a regional flood estimation method for the state of Victoria in Australia as a part of the undergoing update of the ARR. The study divided Victoria into four zones and applied boot-strapping method to estimate relative error values from the developed prediction equations. It has been found from the study that the developed prediction can provide quite accurate predictions. The Northern Victoria (north of the Great Divide Range) generally provides more accurate prediction (with median relative error values in the range of 20 to 32% than the Southern Victoria (relative error values in the range of 23 t 51%). The developed prediction equations require readily obtainable climatic and physical catchment characteristics data and would be relatively easy to apply.