RIVER HEALTH
Rivers are critically important ecosystems which transport freshwater through terrestrial environments providing niche habitats for aquatic vegetation and biota. Rivers also provide an array of ecosystem goods and services such as sources of food and water for terrestrial species. In order to maintain aquatic and terrestrial biodiversity it is critical that our rivers remain in adequate ecological state with minimal impacts on hydrology; one of the most important drivers of river health.
Humankind is always advancing and growing as a population. This in turn impacts our ever-dwindling surrounding natural environments, inclusive of rivers. Construction projects, mining, road laying, and other developments as well as general living can impact our rivers in some way (Adeloye, 2009). Rural communities are usually very dependent on rivers for survival in terms of a source of food and water. Rural communities can also impact on rivers through washing and discarding of waste (Adeloye, 2009). By washing in rivers and discarding of waste and effluents, rivers can become polluted which impacts on river health and all living components and habitats which are dependent on the rivers. Unauthorised and/or unaudited development projects can have more detrimental and long-lasting impacts on rivers by means of direct instream impacts and habitat destruction, pollution through hydrocarbon and/or chemical spills and destruction of riparian habitat.
Mining not only forms a major contributor to the South African economy but also as a major source of impact to rivers through spills, tailings, erosion, sedimentation, acid mine drainage, lowering of the water table, subsidence, and disturbance of the hydrological cycle (Jhariya, et al., 2016). Construction of mine support infrastructure such buildings and roads can also have an impact on the receiving rivers. These impacts include spills, erosion, sedimentation, disturbance of the hydrological cycle, and it can change the rivers flow path by diversions (Walling, 2011).
Prior to any mining or construction project, relevant permits, authorisations and licenses are required to be in place. These provide strict conditions relevant to the pre-construction (planning), construction, operation and decommissioning phases. These conditions are inclusive of recommended measures in terms of the mitigation hierarchy to reduce impacts to the receiving environments. With specific reference to potentially impacted rivers, a Water Use License (WUL) or General Authorisation (GA) will have to be issued prior to any project proceeding. Generally, the WUL or GA will provide a number of water quality parameters with associated limits as provided for in the Target Water Quality Ranges. In order to comply with the conditions of the WUL or GA, the developer will need to undertake regular water quality monitoring to ensure that the development is not impacting on receiving rivers and any impacts to water quality are within the recommended limit as contemplated in the WUL or GA. This is a robust method of monitoring long-term impacts on river systems.
ENVASS has a highly experienced team of aquatic specialists that are able to assist our clients with regular water quality monitoring in the form of in situ water quality, collection of water quality samples for testing at the laboratory, South African Scoring System: Version 5 (SASS5), Fish Response Assessment Index (FRAI) and Vegetation Response Assessment Index (VEGRAI). The team is able to provide project specific, realistic and implementable measures to reduce impacts to rivers based on the results of the abovementioned assessments to ensure compliance with the WUL or GA.
Adeloye, A., 2009. Rivers and Human Development. In: J. Dooge, ed. Fresh Surface Water. Oxford: Eolss Publishers, pp. 117 – 141.
Jhariya, D., Khan, R. & Thakur, G., 2016. Impact of Mining Activity on Water Resource : An Overview study. Recent Practices and Innovations in Mining Industry, pp. 271 – 277.
Walling, D., 2011. Human impact on the sediment loads of Asian rivers. Sediment Problems and Sediment Management in Asian River Basins, pp. 37 – 51.
