Our Specialists

  Johannesburg, South Africa


  +27 11 806 7111

Edwin Lillie, Pr Eng

Consultant, Dams and Water Resources

Edwin Lillie is Dams and Water Resources Consultant based in Knight Piésold’s Johannesburg office. He has over 25 years of working experience as a consulting engineer specializing in dam engineering and water resource modeling.

Edwin is a registered as an Approved Professional Person for Dam Safety Inspections in terms of the South African Dam Safety Regulations, and has been approved for the design and inspections of large dams. He has designed a number of large dams, including the production of working drawings, technical specifications, and contract documents. He has worked on both concrete gravity dams and embankment dams. He also has experience designing pollution containment dams using HDPE liners.

Edwin has experience doing water resource assessments for both hydropower projects and water supply projects. He has experience using the Water Resource Simulation Model (WRSM) for converting rainfall to runoff. He has a particular interest in the Water Resource Yield Model (WRYM) for calculating the reliability of yield from a system. He was the team leader for the project which developed the user interfaces for the WRYM for the Department of Water Affairs.

WRYM is a multipurpose model which can be configured for most water resource system networks using building blocks. Central to the modeling approach adopted in the WRYM is the concept that the configuration of a system network and the relationships between its elements are defined by means of input data, rather than by fixed algorithms embedded in the complex source code of the model. The WRYM model also has a hydropower module incorporated into it. One of the most significant and important features in the model concerns the generation of stochastic flow sequences in the analysis process.  The reliability associated with a given yield requires stochastic inflow sequences and is of the utmost importance to provide an indication of the level of assurance or risk of failure associated with the yield value.