Water is one of our key and indispensable natural resources. It plays a fundamental part in life (and the quality thereof), the environment, food production, hygiene, industry and power generation. Water is one of the major limiting factors in South Africa when it comes to economical growth and social development. In our country water is a scarce resource which is unevenly distributed both geographically and through time. As the demand for water increases, with increasing human populations and economic development, so to does the pollution of our river ecosystems.The Elands River is one of these natural resources that is under constant threat. It falls within the Incomati Water Management Area and is further sub divided into the Crocodile River sub area. This sub area is highly stressed, as it provides water for several human activities. The Elands River is a major tributary of the Crocodile River. The Crocodile River is a source of fresh water for several towns and is used by industry, rural and the agricultural communities (including tobacco farms). The Elands River in turn, is used for irrigation of vegetables. Both these rivers support a rich diversity of aquatic life. Along with its social and economical importance, the Elands River has immense ecological importance, as it holds great biodiversity including critically endangered biota. The main anthropogenic impacts on the Elands and Crocodile rivers include: · The Sappi Ngodwana Mill and the associated pulp and paper activities · The influence of the Ngodwana dam wall on the flow and water quality within the lower Ngodwana River · Nutrient loading taking place due to the treated sewage that is released into the river in the upper reaches and in the vicinity of the Mill · Sedimentation and flow regulation that is taking place in the Crocodile River, upstream of the confluence with the Elands River · And the agricultural activities within the Elands River system. The activities related to the Mill are the major concern in the study. The Sappi Ngodwana Mill is situated at the confluence of the Elands and Ngodwana rivers. The mill does not discharge effluent directly into the river. The effluent is however, irrigated onto the 514 hectares of farmlands adjacent to the Mill. The irrigated effluent has contaminated the groundwater in this area and the primary influence of this groundwater contamination is the deterioration of the surface water quality as well as, negatively impacts the quantity of water in the Elands River. The groundwater enters the Elands River through three springs near Ngodwana namely Fraser’s eye, Northern eye and Eye X. The groundwater from both Fraser’s eye and Eye X has been contaminated with calcium, potassium, magnesium, sulphates and most importantly chlorides. All these substances contribute to the increase in conductivity in the Elands River, which in turn may have a possible impact on the ecological integrity of the system. The pulp and paper industry is a large consumer of water and few regrettable incidents over the years have given the industry a reputation as a major water polluter. The industry’s management of water is,however, of world class and every attempted is made to manage the environment in a sustainable manner. This study aims to assess the impact of these anthropogenic activities on the associated aquatic ecosystems. Assessing the impact of anthropogenic activities on the aquatic environments, like the Elands River, has in the past been based mainly on the assessment of water quality. Earlier management of water resources has thus been based on the potability of water. Over the last decade management initiatives have expanded to include domestic, agricultural, recreational and most importantly instream (fish, invertebrates etc.) users. It has become common practise to use aquatic biota to assess the impacts of human activities of freshwater resources. The reason for this is that animals and plants can provide a long–term integrated reflection of water quality, quantity, habitat quality and other environmental conditions. Water and sediment quality was assessed by applying standard techniques and protocols. Additionally historical water quality data was obtained from the Sappi Ngodwana Mill and the Department of Water Affairs and Forestry. Habitat quality was assessed by implementation of habitat quality indices. This included that Integrated Habitat Assessment Index and the Habitat Quality Index. The vegetation at each site was identified in the field with the assistance provided by the members of the Elands River Valley Conservancy and using various field guides and the riparian zone was then demarked. The integrity of the fish community was assessed by implementing the Fish Assemblage Integrity Index and the Fish Response Assessment Index. The integrity of the aquatic macro invertebrate communities was also assessed. This was achieved through use of the South African Scoring System and the Macro Invertebrate Response Assessment Index. Finally, spatial and/or temporal trends were assessed by implementation of various multi variate statistical procedures. / Prof. J.H.J. Van Vuren Prof. V. Wepene

M.Sc. / The Elands River (Incomati System, Mpumalanga) is a biologically diverse and ecologically important riverine system. In terms of the South African National Water Law, the river can be regarded as an aquatic resource, with social, ecological and economical benefits to the local population and the environment itself. The ecological status of the system has, however been questioned, whereby concerns relating to the water quality and the ecological health of the Elands River has been raised. Initially, the concerns focused on an accidental industrial spill of “black liquor” into the Elands River by the Paper Mill at Ngodwana. Subsequently the groundwater in the vicinity of the Ngodwana Mill has possibly been contaminated with chlorides. The contaminated subsurface water has been discharged into the river, and is suspected to be impacting, primarily in the form of increased salinity, the integrity of the Elands River. This study assessed the ecological integrity of a segment of the Elands River between Waterval- Boven and the confluence of the Elands River with the Crocodile River. In addition this study investigated the possibility that increased chloride-based salinity levels were the factors affecting the ecological integrity of the Elands River. The study is divided into three main components. The environmental component involves the assessment of the surface water quality and flow, physical profile, current aquatic habitat status and a biotic integrity assessment of the Elands River and the Crocodile River directly above and below the confluence with the Elands River. An ecotoxicological component incorporated a bioassay of selected chloride-based salts, using daphnids and selected fish species as test organisms. Finally an Ecological Risk Assessment was carried out to evaluate the likelihood that adverse effects were impacting on the Elands River, as a result of the activities of the Ngodwana Mill. The water quality was assessed by implementing the methodology for the determination of present ecological status: water quality, as part of the preliminary determination of the ecological reserve. Historical water quality data were obtained from the Department of Water Affairs and Forestry and from Sappi. During the study, current water quality parameters were obtained from Sappi and parameters were independently sampled. Analyses of the water quality indicated that the Elands River has been subjected to eutrophication and increased levels of chloride-based salinity. Habitat integrity was analysed by constructing two dimensional site transects of the riparian zone and instream channel. Additional habitat indices, the Integrated Habitat Assessment System, the Habitat Cover Ratings and the Site Habitat Integrity system were applied. Habitat results indicate that the in stream habitats of the Elands River are abundant and linked to the flow regime. Additionally the assessments indicated that the habitat makeup of the Elands and Crocodile rivers is primarily riffle, run and rapids habitats, which facilitate the requirements of numerous invertebrate and vertebrate aquatic communities. Biotic assessments studied the integrity of the vegetation, invertebrates and ichthyofaunal communities. The integrity of the vegetation community was assessed by implementing the Riparian Vegetation Index. Results indicated that the riparian vegetation community was modified in varying degrees due to the encroachment of exotic and terrestrial vegetation elements and by anthropogenic activities. The integrity of the invertebrate communities were assessed by implementing the South African Scoring System. Results indicated that the integrity of the invertebrate community was exceptionally high in the vicinity of Hemlock. The invertebrate community structure changed however in areas were a water quality contamination was observed. The ichthyofaunal attributes were assessed by implementing the Fish Assemblages Integrity Index and the Sensitivity Weighted Index of Biotic Integrity. The ichthyofauna assessment revealed two aspects that have conservation importance. These aspects are the occurrence of an endangered species, Chiloglanis bifurcus, and a potentially geologically isolated subspecies of Labeo-barbus polylepis. The index results indicated that the ichthyofauna community structure followed similar trends to the invertebrates by responding to the mentioned stressors. Toxicological assessments were carried out using the standard Daphnid 48-hour LC50 and fish 96-hour LC50 tests. The species selected for the tests were the currently recognized test organisms (Daphnia pulex and Poecilia reticulata) in South Africa. Additional fish species were included in the tests, these species were Oreochromis mossambicus and Clarias gariepinus. Chloride-based salts were selected as the toxicants; these included calcium chloride, magnesium chloride, potassium chloride and sodium chloride. The tests were carried out under controlled conditions using standardised protocols. Results indicated that in excess, chloride-based salinity is toxic to invertebrate and vertebrate organisms. Additionally findings indicated that potassium chloride was the most toxic and sodium chloride the least toxic of the salts. Calcium chloride was selected as the most representative salt to represent salinity. The Ecological Risk Assessment was implemented after international and national frameworks were considered. The assessment was primarily based on the results obtained from the integrity assessment of the Elands and Crocodile rivers. Results obtained indicated that the localised biological template of the Elands River, in the vicinity of the Ngodwana Mill is moderately impacted by the activities of the Mill. The impact is primarily associated with the increased salinity content of the Elands River. Effects of the stressors were modified in relation to a dilution effect. Risks posed by the stressors are deemed to be restricted to a localised area, and it is highly improbable that the stressors would result in the loss of the biotic diversity and thus the ecosystem of the Elands River as a whole. Should the current situation prevail, the intensity and spatial extent or distribution of the stressor could increase. / Dr. V. Wepener

The South African National Water Act (NWA) (No. 36 of 1998) recognises that in order to sustain the goods and services that are provided by rivers and their associated biological communities, it is necessary to conserve the entire aquatic ecosystem. Conservation and maintenance of ecosystem functioning entails the protection of the biotic components (i.e. fish, macroinvertebrates, riparian vegetation, etc.) and ensuring that the abiotic driver aspects (i.e. required amount and variability of flow, water quality and fluvial geomorphology) are addressed and met (Malan and Day, 2003). According to the Reserve Determination methodology (DWAF, 2003), sustainable utilisation of the river resources requires proper, responsible management and that exploitation without understanding or limits, impacts negatively on the ecological processes, functions and communities, both in the present and the future. Manipulation of the flow regimes of rivers, to provide water when and where people need it, has resulted in a growing deterioration in the condition (health) of riverine ecosystems (King et al., 2000). Stressors on aquatic ecosystems originating from these anthropogenic activities, include point and non-point loadings, land use influences and changes, and stream modification. These are usually defined by the drivers of aquatic ecosystems namely the geomorphology, hydrology and water quality. In turn, the effects on the physical habitat and water quality have both direct and indirect effects on the biotic communities present and are usually defined by biological responses to these changes (Kleynhans et al., 2005). There is currently limited data available to formally propose a methodology to quantify the significance of altered flows in riverine ecosystems brought about by the abstraction or excessive release of water by industrial activities on a reach scale. The aim of this study was to determine the degree and magnitude of habitat-flow alterations caused by pulp and paper mill activities in the Elands and Mvoti Rivers and to link the related biological responses to them. / Prof. V. Wepener