Professor Kobus van Zyl


Hydraulic Engineering​


Professor Van Zyl holds Bachelor and Master’s degrees in Civil Engineering and a Diploma in Scientific Computing from the University of Johannesburg, and a PhD in Civil Engineering from the University of Exeter (UK). He was Chair of the Department of Civil Engineering Science and held the Rand Water Chair in Water Utilisation at the University of Johannesburg before joining UCT in 2009. He is currently the Assistant Dean for Academic Development in the Faculty of Engineering and the Built Environment. 

In 1998 Professor van Zyl chaired the 10th Water Distribution System Analysis (WDSA) Conference, held in the Kruger National Park under the auspices of the American Society of Civil Engineers. This was the first time a WDSA conference had been held outside the USA. 

He has twice been awarded the Best Paper prize in the Journal of the South African Society for Civil Engineering. He is an Associate Editor of the Journal of Water Resources Planning and Management (ASCE), and a member of the Editorial Boards of the Urban Water Journal and SAICE Journal. He is currently vice-chair of the Water Distribution Systems Analysis standing committee of the International Water Resources Institute of ASCE, and is a Steering Committee member of the EPANET Open Source project (

Research interests

His research focuses on water distribution systems, and his current interests include hydraulic modelling, impact of pressure on leakage, reliability of bulk supply systems and water demand management.

Knowledge transfer

Professor van Zyl has published two knowledge transfer books aimed at assisting municipalities with a lack of technical knowledge. These books are available free of charge from the Water Research Commission and can be downloaded from the links below. The books are as follows:


Professor Van Zyl was instrumental in the development of the Aqualibrium water competition (, which is used internationally for outreach and teaching.

Undergraduate course lectures

  • Fluid mechanics (CIV2040S)
  • Hydraulic engineering (CIV3043F)
  • Engineering hydraulics (CIV3043F)

Postgraduate course lectures

  • Design and Modelling of Water Distribution Systems (CIV5121Z)
  • Pressure management (CIV5128Z)​
  • Loss management in water distribution systems (CIV5130Z)


  • Registered as a Professional Engineer with the Engineering Council of South Africa (ECSA)
  • Member of the South African Institution of Civil Engineering (SAICE)
  • Member of the American Society of Civil Engineers (ASCE)
  • Member of the International Water Association (IWA)
  • Fellow of the Water Institute of Southern Africa (WISA)

Milestones and awards

  • Keynote lecture: Kapelan, Z., Van Zyl, J.E., Saldariaga, J., Salomons, E. (2015) “The Open Source Epanet Project”, 13th International Conference on Computing and Control for the Water Industry, CCWI2104, 2 – 4 September, Leicester, UK.
  • Keynote lecture: Van Zyl, J.E. (2015) “Pressure and leakage in water distribution systems”, International lecture series: the future of urban water distribution, 26 May, Universidad de los Andes, Bogota, Colombia.
  • NRF rating: B2.
  • Departmental Research Publication Award for 2014.
  • Finalist, with Marie Ashpole and Fridah Mahlangu, for the NSTF-BHP Billiton Awards for 2012 and 2013 in the category: An Individual or a Team for an outstanding contribution to SETI through Communication for Outreach and creating Awareness over the last five years.
  • South African Institution of Civil Engineering’s award for the Best Journal Paper, 2003, for Van Zyl, J.E., Haarhoff, J., Husselmann, M.L. (2003). “Potential application of end-use demand modelling in South Africa”, Journal of the South African Institution of Civil Engineering, 45 (2) 9-19.
  • South African Institution of Civil Engineering’s award for the Best Journal Paper, 1997, for Van Zyl, J.E., Haarhoff, J. (1997). South African fire water guidelines and their impact on water supply system cost”, Journal of the South African Institution of Civil Engineering, 39 (1) 16-22.
  • Part of project team (as site engineer) that was awarded the South African Institution of Civil Engineering’s Award for Excellence in Civil Engineering: Community Projects, 1995.

Recent Publications

  • Schwaller, J., Van Zyl, J.E., Kabaasha, A.M. (In press) Characterising the pressure-leakage response of pipe networks using the FAVAD equation, Water Science & Technology: Water Supply.
  • Ssozi, E.N., Reddy, B.D., Van Zyl, J.E. (2015) Numerical investigation of the influence of viscoelastic deformation on the pressure-leakage behavior of plastic pipes, Journal of Hydraulic Engineering, DOI: 10.1061/(ASCE)HY.1943-7900.0001095.
  • Couvelis, F.A., Van Zyl, J.E. (2015) “Apparent losses due to domestic water meter under-registration in South Africa”, Water SA 41 (5) 699 – 704, DOI 10.4314/wsa.v41i5.13.
  • Pieterse-Quirijns, E. J., van Thienen, P., de Sousa-Alves, M., Deyi, M., van Zyl, K., de Kater, H., van de Roer, M., Holzhaus, P., Klein-Arfman, M. and van Duist, H. (2015) “Application and exchange of water distribution system knowledge in South Africa”, published in Dutch as “Toepassing en uitwisseling van waterdistributiekennis in Zuid-Afrika”. H2O-Online, 20 januari 2015.
  • 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, 04014089-1-8, 10.1061/(ASCE)HY.1943-7900.0000984
  • Piller, O., Van Zyl, J.E. (2014) “Modeling Control Valves in Water Distribution Systems Using a Continuous State Formulation”, Journal of Hydraulic Engineering, 140 (11).
  • Chang C.-C., Van Zyl, J.E. (2014) “Speeding up stochastic analysis of bulk water supply systems using a compression heuristic”, WaterSA, 40 (3) 395-400.
  • Griffioen, M.L., Van Zyl, J.E. (2014) “Modelling water demand on a suburb level”, Journal of the South African Institution of Civil Engineering, 56 (1) 63-68.
  • Adewumi, J.R., Ilemobade, A.A., Van Zyl, J.E (2014) “Factors predicting the intention to accept treated wastewater reuse for non-potable uses amongst domestic and non-domestic respondents”, Journal of the South African Institution of Civil Engineering, 56 (1) 11-19.
  • Siebrits, R. M., Winter, K., Barnes, J., Dent, M.C., Ekama, G., Ginster, M., Harrison, J, Jackson, B., Jacobs, I, Jordaan, A., Kasan, H.C., Kloppers, W., Le Roux, R., Maree, J., Momba, M. N. B., Munnik, A. V., O’Keeffe, J., Schulze, R., Silberbauer, M., Still, D., Van Zyl, J.E. (2014) “Priority water research questions for South Africa developed through participatory processes”, Water SA, 40 (2), 199 – 209.
  • Chang C.-C., Van Zyl, J.E. (2014) “Optimal reliability-based design of bulk water supply systems”, Journal of Water Resources Planning and Management, 140 (1) 32 - 39
  • Van Zyl, J.E., Cassa, A.M. (2014) “Modeling elastically deforming leaks in water distribution pipes”, Journal of Hydraulic Engineering, 140 (2) 182 – 189.
  • Van Zyl, J.E., Alsaydalani, M.O.A., Clayton, C.R.I., Bird, T., Dennis, A. (2013). “Soil fluidisation outside leaks in water distribution pipes – preliminary observations”, Proceedings of the Institution of Civil Engineers: Water Management, 166 (WM10) 546 – 555.
  • Adewumi, J.R., Ilemobade, A.A., Van Zyl, J.E. (2013) Application of a multi-criteria decision support tool in assessing the feasibility of implementing treated wastewater reuse, International Journal of Decision Support System Technology, 5 (1) 1-23.
  • Cassa, A.M., Van Zyl, J.E. (2013) Predicting the pressure-leakage slope of cracks in pipes subject to elastic deformations, Journal of Water Supply: Research and Technology – AQUA, 62 (4) 214-223.
  • Van Zyl, J.E., Legat, Y., Piller, O., Walski T.M. (2012). “Impact of water demand parameters on the reliability of municipal storage tanks”, Journal of Water Resources Planning and Management, 138 (5) 553–561.
  • Crous, P.A., Van Zyl, J.E., Roodt, Y. (2012) “The potential of graphical processing units to solve hydraulic network equations”, Journal of Hydroinformatics, 13 (3) 603-612.
  • Lugoma, M.T.F., Van Zyl, J.E., Ilemobade, A.A. (2012) “The extent of on-site leakage in selected suburbs of Johannesburg”, Water SA, 38 (1) 127-132.
  • Adewumi, J.R., Ilemobade, A.A., Van Zyl, J.E. (2012) “Minimizing risks in wastewater reuse: proposed operational principles and guidelines for South Africa”, Journal of Water Reuse and Desalination, 2 (4) 227 – 238.