Professor Kobus van Zyl

Ph.D. in Civil Engineering, University of Exeter


Kobus van Zyl received bachelor's and master’s degrees in Civil Engineering from the University of Johannesburg in 1990 and 1993 respectively. After a few years working for a consulting engineering company, he joined the University of Johannesburg again as a lecturer. He was awarded a Commonwealth Academic Staff Scholarship to do a PhD at the University of Exeter from 1998 to 2001, under supervision of Professors Dragan Savic and Godfrey Walters. The topic of his PhD research was improved operational optimisation of water distribution systems using a hybrid genetic algorithm, combined with a novel approach to extended period network modelling. 

He was Chair of the Department of Civil Engineering Science and held the Rand Water Chair in Water Utilisation at the University of Johannesburg. He joined the University of Cape Town in 2009 where he was the Assistant Dean for Academic Development in the engineering faculty in 2014 and 2015 and deputy Head of Department in 2018. He recently joined the University of Auckland as the Watercare Chair for Infrastructure.

Kobus is a Professional Engineer, an Associate Editor of the ASCE Journal of Water Resources Planning and Management and a member of the Editorial Board of the Urban Water Journal. He is the Past-Chair of the ASCE Environmental and Water Resources Institute’s standing committee on Water Distribution Systems Analysis and a member of the EPANET Visioning Task Committee. 

Kobus’s research has focused on water distribution systems, including hydraulic network theory, reliability of bulk supply systems, water demand modelling, water metering, the behaviour of pipe leaks and soil-leak interaction. In his new role as Watercare Chair for Infrastructure his research is expanding to include the wider infrastructure field from a multi-disciplinary viewpoint. 

Kobus's research group has been at the forefront of work to better understand the behaviour of leaks in water distribution systems for more than a decade. The aim of this work has been to identify and quantify the fundamental mechanisms responsible for the observed behaviour of leaks with changes in pressure. His research team has used an array of research approaches that include analytical, laboratory, hydraulic modelling, numerical modelling and field work, and has collaborated with experts in other fields to address multidisciplinary aspects of the problem. Their  research has been published in top international journals and recently resulted in two international patent applications. 

Kobus's research on leakage was noted as one of the “top five research works in the past few decades in water distribution planning and management” in an editorial by Dr Tom Walski [1] in the ASCE Journal of Water Resources Planning and Management. In addition, Allan Lambert [2], the doyen of leakage management practice, stated in a 2013 conference paper: “The principal theoretical advance in understanding of pressure - leak flow rate relationships since 2005 has been the development by the University of Johannesburg and the Cape Town University group of the concept of Leakage Numbers to explain variations in the FAVAD N1 exponent for different types of cracks in pipe

Kobus has been recognised by peers in the form of invitations to present keynote lectures at the Universidad de los Andes, Bogota, Colombia in 2015 (as part of the 20th year celebration of their PAVCO Chair), the 13th International Conference on Computing and Control in the Water Industry at De Montfort University, Leicester in 2015 and the 18th International Conference on Water Distribution System Analysis in Cartagena, Colombia in 2016. He has close ties with industry and have collaborated on research projects with several municipalities, consulting engineers and manufacturers. I have also presented short courses on various water distribution system topics to industry in South Africa, the UK and Canada. 

Kobus is passionate about teaching and has developed the Aqualibrium Water Competition, a physical pipe network challenge that is used for outreach and both undergraduate and postgraduate teaching at several universities around the world. 

[1] Walski, T. (2014) Consequential Research (Editorial), Journal of Water Resources Planning and Management140(5) 559-561. 

[2] Lambert, A., Fantozzi, M. and Thornton, J. (2013), “Practical approaches to modeling leakage and pressure management in distribution systems – progress since 2005”, 12th International Conference on Computing and Control in the Water Industry CCWI2103, Perugia, Italy. 

Research | Current

  • Pressure management in Water Distribution Systems
  • Water loss modelling and management
  • Integrated water meter management
  • Design, operation and maintenance of Water Distribution Systems
  • Epanet modelling of Water Distribution Systems
  • Infrastructure systems

Teaching | Current

CIVIL 230 Fluid Mechanics

CIVIL 331 Hydrauilc Engineering

CIVIL 705 Part IV Research Project

CIVIL 756 Capstone Project


  • ASCE Journal of Water Resources Planning and Management, 2020 Best Associate Editor Award 
  • Conference Chair, 10thInternational Water Distribution System Analysis Conference (WDSA 2008), Kruger National Park, South Africa, 17-20 August 2008
  • Profiled in the ASCE Water Distribution System Analysis history project.
  • Finalist, National Science and Technology Forum BHP Billiton Awards: Outstanding Contribution to SETI Through Communication for Outreach and Creating Awareness, 2013 and 2014
  • Best Poster Prize, Water Institute of Southern Africa Biannual Congress, 2008
  • Best Poster Prize, Water Institute of Southern Africa Biannual Congress, 2006
  • Award for the Best Paper in 2003, Journal SAICE 
  • Award for the Best Paper in 1997, Journal SAICE
  • British Commonwealth Academic Staff Scholarship for Ph.D. studies in the UK, 1998-2001
  • Award for Excellence in Civil Engineering: Community Projects, SAICE, 1995 


  • Associate Editor, ASCE Journal of Water Resources Planning and Management
  • Editorial Board Member, Urban Water 
  • Editorial Board Member, Journal of the South African Institution of Civil Engineering

Committees/Professional groups/Services

  • Member, ASCE Standing Committee on Water Distribution System Analysis
  • Member, International Scientific Committee, Annual International Water Distribution System Analysis Conference (WDSA), since 2006
  • Member, International Scientific Committee, Biannual International Conference on Computing and Control in the Water Industry (CCWI), since 2004
  • Member, Host Selection Committee of the 2020 Combined CCWI/WDSA Conference 
  • Member, Organising Committee,18thAnnual Water Distribution System Analysis Conference (WDSA 2016), Cartagena, Colombia, 2016
  • Member, International Water Association Water Loss Task Force, since 2003
  • Member, Epanet Open Source Steering Committee, since 2015 

Selected publications and creative works (Research Outputs)

As of 29 October 2020 there will be no automatic updating of 'selected publications and creative works' from Research Outputs. Please continue to keep your Research Outputs profile up to date.
  • Niebuhr, D., Nsanzubuhoro, R., & van Zyl, J. E. (2020). Field experience with pressure-based leakage characterisation of bulk water pipelines. URBAN WATER JOURNAL, 16 (10), 709-717. 10.1080/1573062X.2020.1726411
  • Pike, S. M., van Zyl, J. E., & Clayton, C. R. (2018). Scouring Damage to Buried Pipes Caused by Leakage Jets: Experimental Study. JOURNAL OF PIPELINE SYSTEMS ENGINEERING AND PRACTICE, 9 (4)10.1061/(ASCE)PS.1949-1204.0000328
  • Kabaasha, A. M., Piller, O., & van Zyl, J. E. (2018). Incorporating the Modified Orifice Equation into Pipe Network Solvers for More Realistic Leakage Modeling. Journal of Hydraulic Engineering, 144 (2), 04017064-04017064. 10.1061/(ASCE)HY.1943-7900.0001410
  • van Zyl, J. E., Lambert, A. O., & Collins, R. (2017). Realistic Modeling of Leakage and Intrusion Flows through Leak Openings in Pipes. Journal of Hydraulic Engineering, 143 (9), 04017030-04017030. 10.1061/(ASCE)HY.1943-7900.0001346
  • van Zyl, J. E., & Malde, R. (2017). Evaluating the pressure-leakage behaviour of leaks in water pipes. Journal of Water Supply: Research and Technology - Aqua, 66 (5), 287-299. 10.2166/aqua.2017.136
  • Ssozi, E. N., Reddy, B. D., & van Zyl, J. E. (2016). Numerical Investigation of the Influence of Viscoelastic Deformation on the Pressure-Leakage Behavior of Plastic Pipes. Journal of Hydraulic Engineering, 142 (3), 04015057-04015057. 10.1061/(ASCE)HY.1943-7900.0001095
  • Schwaller, J., Van Zyl, J. E., & Kabaasha, A. M. (2015). Characterising the pressure-leakage response of pipe networks using the FAVAD equation. Water Science and Technology: Water Supply, 15 (6), 1373-1382. 10.2166/ws.2015.101
  • Schwaller, J., & van Zyl, J. E. (2015). Modeling the Pressure-Leakage Response of Water Distribution Systems Based on Individual Leak Behavior. Journal of Hydraulic Engineering, 141 (5), 04014089-04014089. 10.1061/(ASCE)HY.1943-7900.0000984


Contact details

Primary office location

Level 12, Room 1209
New Zealand

Web links