G. C. Bate

The Maputaland coastal plain is situated on the north-east coast of South Africa. It is important to the South African economy because of the number of game parks that draw tourists to the area and South Africa. Essentially a rural area with a relatively small local population, the introduction of forestry plantations in the 1950s resulted in opportunities for the local Maputaland people. The war in Mozambique in the latter 20th century resulted in many South Africans not holidaying in that country. This prompted the then Natal Parks Board to establish beach and sea-based holiday facilities at Sodwana early in the 1970s. This is an area that is now within the iSimangaliso Wetland Park World Heritage Site. The establishment of forestry resulted in an inflow of people to the area eager to obtain employment. A steady rise in the number of tourists to the area further improved the availability of jobs. There has been a rise in the annual numbers of visitors utilising the facilities of the area. The provision of water includes a municipal supply from Lake Sibaya that is treated in the town of Mbazwana and piped to local residents. This service has become inadequate causing dissatisfaction. Added to the problem has been the development of a considerable number of private holiday establishments additional to the Sodwana facility situated outside the Park and therefore outside its jurisdiction. The increased number of people living in and visiting the area has meant that the original local municipal water supply became totally inadequate, resulting in the sinking of boreholes by both local people and the commercial holiday facility operators. There is no municipal sewage system in the area and waste water is discharged into the ground and hence into the groundwater. This has resulted in borehole water showing higher than natural levels of nutrients that in turn are having an adverse impact on the quality of the groundwater, the lakes and the estuary in the area. To protect the local ecosystem and economy it is important that a formal sewage system be provided. Disposal of household waste from the area will be difficult because of the terrain and will have to be carefully planned to provide an adequate system that will protect the natural environment which attracts tourists and is the basis of the local economy.

Maputaland is a natural environment situated along the northeast coast of South Africa. Within this area a small section of about 8000 ha was studied with respect to the quality of water from incoming rainfall, the groundwater, the streams and lakes to the outflow through the small Mgobezeleni Estuary. The study area is a representative sample of the Maputaland Coastal Plain that runs from the Lake St Lucia World Heritage site to the Mozambican border. All the water in the area emanates from rainfall with no rivers flowing into the area. Projects initiated from the 1960s by the government in order to improve the welfare of the local population have resulted in a large influx of people, both residents and tourists. The population in the catchment is made up of a relatively small local population that has risen from almost zero in 1970 to about 15 000 in 2015. There is a large annual visiting population of up to 250 000 that is economically valuable to the small resident population. The result is that accommodation facilities have increased together with the necessary infrastructure of water supplies and sewage facilities. The groundwater quality indicates that the sewage facilities are impacting the nitrogen and phosphorus concentrations but that these levels are not present in the lakes into which the groundwater flows. The presence of large amounts of fringing macrophytes in one lake and a high density of cyanophyte microalgae (or cyanobacteria) in the other indicates that sewage pollution is the cause. However, the lakes appear to be removing much of the sewage pollution because the estuary water below the lakes has a high quality. These data suggest that similar pollution might adversely affect other areas of Maputaland, which have a growing tourist population attracted to the Maputaland game parks.

The blackwater Mgobezeleni Estuary is a small system below a peat swamp. From the air the estuary is completely black, but the water revealed only a light tea colouration with a Secchi reading of >1.7 m. The sediment is covered with black low-density fragments overlying light coloured sand. When the estuary is open the colouration of the sea is blacker than might be expected from the light tea-coloured estuary water. The results of X-ray spectroscopy showed the black fragments have a high carbon content that is most likely peat. The dissolved organic carbon content of the Mgobezeleni Estuary water is lower than that in Swartvlei in the South Western Cape, which has very dark water. The presence of very large deposits of peat at the head of the estuary together with spectroscopy data indicate that the colouration of the water emanates from leached leaves of swamp vegetation. The penetration of light through the water is not reflected from the light sand due to the peat covering, giving the appearance of very dark water. The literature suggests that the cause of blackwater is due to humic acids, peat and tannins leached from fallen leaves. The results of this study point to peat fragments not reflecting sunlight rather than peat extract and humic acids as the main cause. The slight colouration of the water is likely due to the small amount of fresh leaf litter in the catchment for the release of tannins that colour the Mgobezeleni Estuary water.