A heavy vehicle simulator (HVS) was used to evaluate a high-standard crushedstone base pavement near Jan Smuts Airport on Road P157/2. Short sections of the road were rebuilt with improved drainage where the previous pavement had failed due to drainage problems and the settlement of fills. The purpose of the test was to determine whether the rebuilt pavement could carry the expected traffic over the next 20 years and how it would react to the effects of poor drainage conditions.
Hydrological techniques for the estimation of floods have not advanced much since the development of unit hydrograph methods in the 1930s. The technique of discounting losses using a coefficient has been readily adopted without a great deal of thought. The linear hydrological methods have all sprung from the same reasoning. It is invariably assumed that the design storm for any catchment is that with a duration corresponding to the travel time down the catchment. The flood due to 2 mm of effective rainfall Is assumed to be twice that due to 1 mm of rainfall.