Prior to 1956 As has happened throughout the world, environmental and pollution problems related to developing towns and industries and the associated accumulation of waste in built-up areas were the main factors that contributed to sanitary awareness in this country. Initially the control of water pollution in South Africa was closely associated with the development of sewage disposal methods and practice. In a development similar to that in many other countries, bucket sanitation systems and septic tanks were the first steps on the path of proper sewage disposal. Septic tanks were installed by the British military authorities at various military camps in South Africa. The first municipal scheme to be put into operation was in Bloemfontein. The system consisted of septic tanks and primary and secondary filters, followed by irrigation of 100 ha of cultivated land. Sewage arrived at the works in November 1904, some two months ahead of fairly similar works in Wynberg in the Cape.
Models are examples of the art of hydraulic engineering that, in the words of Osborne Reynolds nearly a century ago, are a means 'which after what I have seen, I shall feel it madness to neglect before entering upon any costly undertaking'. Through the intervening years, since Reynolds first performed his classical experiments on laminar and turbulent flow in a tube, thousands of model experiments of important hydraulic projects have been carried out in hundreds of hydraulic laboratories throughout the world. In South Africa most of this work has been done since the 1950s. (In two other articles in this issue a review is made on progress in two related fields, energy dissipation and coastal protection.) It is reassuring that on important Southern African water and power projects significant portions of the hydraulic model investigations have been carried out in South Africa, side by side with parallel studies in Europe. This shows that the South African engineering profession can enjoy the accredited services of our institutions equipped with fully operational hydraulic laboratories. In this field of study we as hydraulic engineers in South Africa have at last also become 'of age'.