4.3.1 Population growth: 

Population growth in the coastal zone will continue to put a pressure on resources because of the growing demand for land for housing and other development, demands on living resources for food, recreation and fresh water. Such pressures are not evenly distributed along the coast and are mostly associated with urban centres, although intense harvesting of living resources tend to also be associated with rural areas. Pressures on coastal resources that are linked to the human population level and economic status will continue indefinitely. Even if the population is stabilised, improved standards of living may cause people to become more consumeristic and wasteful. This will mean just as many resources being used.

Human demand for fresh water places pressure on estuaries in the form of reduced freshwater inflows and altered hydrological regimes, and flooding as a result of major dam developments and the abstraction of irrigation water. Estuarine organisms depend on specific salinity regimes which are controlled by freshwater inflow (volume and seasonal patterns of flow).

Figure 4.7 Population growth rate

Patterns of resource use and pressures, which are closely linked to population size and economic status, vary depending on factors such as the subsistence or artisanal nature of the resource use and the industrial, urban and recreational character of the demands placed on the coastal resources.

4.3.2 Emissions to sea: 

Some 63 ocean outfalls are located along the South African coast and these discharge approximately 800 000 cubic metres of sewage and industrial effluent into the sea daily. Most large pipelines discharge into deeper waters, but 27 of the older pipelines discharge above the high water mark. This is more dangerous to human health as bathing waters are contaminated, and edible species such as mussels may become contaminated.

Figure 4.8 Effluent pipelines off the South African coast after Cloete (1979)

In addition to the outfalls shown in Figure 4.8, there are two pipelines at Richards Bay, outfalls servicing Tongaat textiles, AECI, Tioxide, SAPPI SAICCOR and the formaldehyde plant at Sezela on the KwaZulu-Natal coast, an oil refinery outfall at Milnerton, and the fish factories outfalls at Saldanha Bay in the Western Cape.

Major environmental pressures associated with the marine discharge of sewage and industrial emissions include organic enrichment, nutrient enrichment, increase in concentrations of suspended solids, effects of harmful substances such as metals and poly-aromatic hydrocarbons. Several effluent constituents have carcinogenic (cancer causing) effects on humans. The volume of storm water run-off entering the marine environment is difficult to quantify as there are so many sources. In 1991 the total volume was estimated to be about 876 000 cubic metres/ day. All storm water discharge ultimately drains into the marine environment and, where this is untreated, it poses a pollution risk to a variety of beneficial water uses; e.g. coastal recreation, mariculture (Saldanha Bay, Algoa Bay) and communities of marine biota.

Pressures associated with shipping include operational and major oil spills and the discharge of ballast water and waste from vessels. Oil spills and discharge of ballast water lower marine water quality making it less suitable for human as well as marine ecosystem functions, particularly around commercial ports. Inputs from these sources of pollution are very difficult to quantify.

>     Marine and Coastal Systems: Pressures #2

There is also information about Terrestrial Ecosystems in the following reports:
Metropolitan reports:
	Cape Metropolitan Council (1998 edition)		Durban Pilot Study
	Greater Johannesburg Metropolitan Council (1999 edition)		Greater Pretoria Metropolitan Council (1999 edition)