WBNM runoff routing parameters for south and eastern Australia

Abstract

The lag parameter C in the runoff routing model WBNM has been derived from recorded storms on 54 catchments in Queensland, NSW, Victoria and South Australia. Parameter C was found to be independent of flood size, catchment area, stream slope, and various storm and catchment characteristics. A review of studies on velocity variations within catchments, and lag time variations between catchments supports these results. The area-standardised lag parameters of several widely used runoff routing models are shown to be related to one another. From the study, a value of C = 1.6 is recommended for use on ungauged catchments.

Keywords:

• Flood hydrographs
• runoff routing
• catchment lag time
• slope and lag time
• hydrology and geomorphology
• stream length and catchment area
• Manning roughness and slope
• stream velocity variation

Additional information

Notes on contributors

M J Boyd

Michael graduated in Civil Engineering from the University of New South Wales in 1977, and subsequently went to the University of Wollongong, where he is currently Associate Professor in the Faculty of Engineering.

His research interests are flood hydrology, urban stormwater management, and water resources, and he has published more than 80 papers in these areas. His research into flood hydrograph modeling, flood frequency analysis, flood detention basin design, and culvert hydraulics is referenced in the Engineers Australia Guide to Flood Estimation, Australian Rainfall and Runoff (1987, 1997).

Michael Boyd is a developer of the flood hydrograph model WBNM for natural and urban catchments. Details of this are available at www.uow.edu.au/eng/cme/research/wbnm.html.

N D Bodhinayake

Nanayakkara has taught Civil Engineering for 12 years at the NSW TAFE Commission of Australia. He has also worked as a writer, reviewer and assessor for the Open Training and Education Network (OTEN) of TAFE. During his time at OTEN he developed distance education learning materials for modules in Stormwater Drainage and Hydraulic Mechanics. These modules are currently being used for the delivery of nationally accredited external Diploma courses in TAFE organizations across Australia.

He worked at the Ministry of Higher education in Sri-Lanka from 1984 to 1990, during which time he held the positions of Additional Director of Technical Education, and Head of Department and Deputy Principal of the National Technical Teacher’s Training College. From 1975 to 1983 he worked at the Colombo Port Commission and the Coast Conservation Department of Sri-Lanka, becoming Chief Engineer.

Nanayakkara graduated with a BE in Civil Engineering from the University of Sri-Lanka in 1975. He was awarded a UNESCO scholarship to the International Institute for Hydraulic Engineering, Netherlands, where he obtained a Postgraduate Diploma in Coastal Engineering in 1981. In 1986 he was awarded a UNDP scholarship to study at the University of Manchester where he obtained his Advanced Diploma in Technical Education. After migrating to Australia in1991 he obtained his Graduate Diploma in Secondary Education from the University of Technology, Sydney in 1992. In 2004 he was awarded a PhD from the University of Wollongong for his thesis Influence of Hydrological, Geomorphological and Climatological Characteristics of Natural Catchments on Lag Parameters.

Curently he is reading for a Doctor of Education degree at the University of Wollongong on the topic Statistical Understandings in TAFE Colleges and Universities.