M.Sc. / The South African Water Act (Act 54 of 1956) was promulgated in 1956. Section 21 of this Act required the permitting of all effluent dischargers, including sewage works. The General and Special Standards were subsequently published in the Government Gazette in 1984 in accordance with this Act, which set effluent discharge quality limits for such discharges. This was the Uniform Effluent Standard approach. However, this approach did not take into account the assimilative capacity of the receiving water, or limitations thereof. This resulted in a decrease in the water quality in the nations' water resources (DEAT 1999). The White Paper on Water Policy in South Africa was published by the Department of Water Affairs and Forestry in 1997. This paper identified this concern and suggested a change in the way water quality was managed in the country. The National Water Act (Act 36 of 1998) was subsequently promulgated in 1998, and provided the tool to effect these changes. This Act adopted the Receiving Water Quality Objectives (RWQO) approach. This approach takes into account the impacts on the receiving water as well as the impacts on other water users. This mini-thesis compared SA legislation regulating the discharge of wastewater, and more specifically sewage effluent, into the environment, by comparing it to first world legislation performing the same function. The effectiveness of the implementation of the SA legislation was also investigated. This study concluded that the promulgation of the National Water Act of 1998 (Act 36 of 1998) brought SA legislation on par with first world trends. This is an advanced piece of legislation, the effects of which are only now beginning to be felt. Much of the changes required by this Act are still being initiated and may take years to fully implement. Most dischargers still have valid permits issued in terms of the Water Act of 1956 (Act 54 of 1956), and these permits must be replaced by licenses issued in terms of the National Water Act of 1998 (Act 36 of 1998). An important conclusion from this study is that the legislation is not prescriptive in terms of specifying discharge license conditions, but instead allows the relevant authority, the Department of Water Affairs and Forestry to adjust the stringency of such licenses to suite the degree of impacts resulting from such discharges. Discharge licenses are therefore very site-specific and tailored to suite the type of discharge and impacts on the receiving water and other water users. In this way the requirements of all water users, including the aquatic ecosystem of the receiving water body, are taken into account, and protected. One suggested improvement to the SA legislation however, is to regulate industrial dischargers to sewer using national legislation. This is currently regulated by the by-laws of the relevant local authority, but is often insufficient to protect the sewage works and ensure the proper functioning of these works, which is largely dependant on the quality of raw sewage intake. Further research is required to determine the impact of industrial dischargers to sewer, and investigate how to regulate such discharges using national legislation. This study additionally assessed the implementation of SA legislation and the effectiveness of control over sewage dischargers. Enforcement of this legislation is not necessarily uniform, since much of the responsibility to enforce discharge permits and licenses lie with various officials within the Department of Water Affairs and Forestry. One way to ensure uniformity would be to require regular auditing by higher levels and management within this Department. Another important aspect of enforcement of these permits and licenses is that all permit and license holders, including Local Authorities, should be treated in the same way.

[Truncated abstract]This thesis investigates aspects of urban stormwater modeling and uses a small urban catchment (NE38) located in the suburb of Nedlands in Perth, Western Australia to do so. The MUSIC (Model for Urban Stormwater Improvement Conceptualisation) model was used to calibrate catchment NE38 using measured stormwater flows and rainfall data from within the catchment. MUSIC is a conceptual model designed to model stormwater flows within urban environments and uses a rainfall-runoff model adapted to generate results at six minute time steps. Various catchment scenarios, including the use of porous asphalt as an alternative road surface, were applied to the calibrated model to identify effective working stormwater disposal systems that differ from the current system. Calibrating catchment NE38 using the MUSIC model was attempted and this involved matching modeled stormwater flows to stormwater flows measured at the catchment drainage point. This was achieved by measuring runoff contributing areas (roads) together with rainfall data measured from within the catchment and altering the seepage constant parameter for all roadside infiltration sumps. ... The MUSIC model generated future scenario outcomes for alternative stormwater disposal systems that displayed similar or improved levels of performance with respect to the current system. The following scenarios listed in increasing order of effectiveness outline future stormwater disposal systems that may be considered in future urban design. 1. 35% porous asphalt application with no sumps in 2036 2. 35% porous asphalt application with no sumps in 2064 3. 68% porous asphalt application with no sumps in 2036 4. 68% porous asphalt application with no sumps in 2064. Future scenarios using the current stormwater disposal system (with roadside infiltration sumps) with porous asphalt were also run. These scenarios reduced stormwater runoff and contaminant loading on the catchment drainage point however the inclusion of a roadside infiltration sump system may not appeal to urban designers due to the costs involved with this scenario. Climate change will affect the design of future stormwater disposal systems and thus, the design of these systems must consider a rainfall reducing future. Based on the findings of this thesis, current stormwater runoff volumes entering catchment drainage points can be reduced together with contaminant loads in urban environments that incorporate porous asphalt with a stormwater disposal design system that is exclusive of roadside infiltration sumps.