| dc.description.abstract | Situated in the north-eastern region of South Africa is the Sabie-Sand River catchment. Initially seen as the separate Sabie catchment draining the Sabie River, and the Sand catchment draining the Sand River, these drainage basins are collectively classified by The Department of Water Affairs and Sanitation (DWS) as the X3 secondary drainage region. This catchment lies to the north of the greater Inkomati-Usuthu Water Management Area (IUWMA). The primary Sabie River flows from its headwaters originating east of the Great Escarpment through various towns, such as Sabie, Hazyview and Skukuza, which is situated in the Kruger National Park (KNP) to its cross-boundary end in the Corumana Dam, Mozambique. Two of its tributaries were considered important within this study (Sand and Marite rivers) as well as the Inyaka Dam (also called Injaka Dam) situated within the Marite River. Forestry, commercial plantations, cultivated commercial lands and urban land uses were suspected of having increasing water demand on the water resources of the catchment. The densely populated, rural or semi-urban developments within the catchment have raised increasing concerns over the past two decades due to the substantial increase in population. Initially it was pressures from the increasing water supply (lifted by the Integrated Water Supply Scheme from the Inyaka Dam) that impaired the livelihoods of the still expanding Bushbuckridge community. Now, water quality has raised increasing concerns with regards to both Bushbuckridge and the urban township Thulamahashe. As responsibility towards the conservation practices of the KNP; the international water agreement between South Africa, Swaziland and Mozambique; and the protection of catchment water resources, this study was initiated with regards to the influence of land use on water quality. It is very important to note that certain parts of South Africa had suffered a climatological drought from 2013 to 2016, so this study assessed the river water quality experienced within a dryer rainfall period and should be interpreted as such. This relates to an international issue of concern, namely dwindling potable water supply. Intense human activities conducted by using earth’s surfaces, influence water quality. It has become highly important to assess water issues with regards to land use as indicator of human activities. The main aims of this study were to do an in-depth determination of the different land uses surrounding the Sabie-Sand River Catchment; and to evaluate the influence thereof on the water quality of the Sabie River and its two major tributaries including the Inyaka Dam. It also focused much attention on the possible effects that urbanization had on water resource quality. Therefore, it was necessary to conduct in situ field investigations and GIS spatial analysis towards answering the research problem. Every three months, surface water samples were collected form 12 sites in the Sabie-Sand catchment. This was done over a period of a year, as to include results from all four climate seasons. Major chemical, biological and physical water quality parameters were measured; analysed with accredited methods from the South African National Accreditation System (SANAS) by Rand Water Analytical Services laboratory, and interpreted by use of Spearman Rank correlation and Kruskal-Wallis ANOVA statistical methods. Spatial analysis conducted through ArcGIS version 10.4 (Esri, 2015), made use of the 3D analyst, spatial analyst and network analyst extensions in ArcGIS for land use interpretation. The main spatial datasets used for interpretation were the 2013/2014, 72 Class South African National Land Cover Dataset (GeoTerraimage, 2015) and the SRTM90 Digital Elevation Model (DEM) (Jarvis et al., 2008). Assessing spatial influences on water quality, a multivariate redundancy analysis (RDA) was conducted to compare both datasets. The results indicated that there was no significant relationship between land use and water quality for the Sabie-Sand catchment, but it was identified that land use still played a major role in the water quality of the catchment. Since the state of the rivers report conducted by Roux and Selepe (2011), the land uses in terms of forestry and the upper part of the Sabie River have not changed as much as the urban expansion of peri-urban areas, urban villages and urban townships have. The reason for saying this is that forestry, commercial plantations and cultivated commercial lands showed lesser adverse influence on water quality and that the major negative influences were urban in nature. The urban township Thulamahashe had the most negative impact on the water quality of the Sand River, tributary of the Sabie River. This was related back to effluent from the wastewater treatment plant on the Sand River. Discussed in Chapter 4 of this study are the water quality parameters that identify organic pollution from anthropogenic activities. These parameters were either high or in exceedance of drinking water standards. This is seen in exceedingly high Escherichia coli (E. coli) and Total Coliforms (coli) concentrations that were associated with high Chlorophyll-a (Chl-a), Chemical Oxygen Demand (COD), dissolved inorganic nitrogen (DIN), Dissolved Organic Carbon (DOC) and geosmin. With low concentrations of DO for this site, accompanied with the high coli, DOC, Total Organic Carbon (TOC) and COD this might indicate rapid bacterial growth. Support should be provided to this urban settlement in the form of adequate water supply and sanitation facilities, primarily starting with the known point pollution wastewater treatment plant. Adequate maintenance and monitoring should be insisted on at the plant to ensure effluent that conform to national water quality guidelines. | en_US |
