What is Water Quality?
Water quality is a term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for an intended purpose. These characteristics are controlled or influenced by substances, which are either dissolved or suspended in water.
Although scientific measurements are used to define the quality of water, it’s not a simple thing to say that ” this water is good ,” or ” this water is bad “. The quality of water that is required to wash a car is not the same quality that is required for drinking water. Therefore, when we speak of water quality, we usually want to know if the water is good enough for its intended use, be it for domestic, farming, mining or industrial purposes, or its suitability to maintain a healthy ecosystem.
What is Water Quality Management?
Water quality is changed and affected by both natural processes and human activities. Generally natural water quality varies from place to place, depending on seasonal changes, climatic changes and with the types of soils, rocks and surfaces through which it moves. A variety of human activities e.g. agricultural activities, urban and industrial development, mining and recreation, potentially significantly alter the quality of natural waters, and changes the water use potential. The key to sustainable water resources is, therefore to ensure that the quality of water resources are suitable for their intended uses, while at the same allowing them to be used and developed to a certain extent. Effective management is the tool through which this is achieved. Water quality management, therefore involves the maintenance of the fitness for use of water resources on a sustained basis, by achieving a balance between socio-economic development and environmental protection. From a regulatory point of view the “business” of water quality management entails the ongoing process of planning, development, implementation and administration of water quality management policy, the authorisation of water uses that may have, or may potentially have, an impact on water quality, as well as the monitoring and auditing of the aforementioned.
Why the need to manage Water Quality?
The effects of polluted water on human health, on the aquatic ecosystem (aquatic biota, and in-stream and riparian habitats) and on various sectors of the economy, including agriculture, industry and recreation, can be disastrous. Deteriorating water quality leads to increased treatment costs of potable and industrial process water, and decreased agricultural yields due to increased salinity of irrigation water. On the other hand not all health, productivity and ecological problems associated with deteriorating water quality are ascribed to man’s activities. Many water quality related problems are inherent in the geological characteristics of the source area. The occurrence, transport and fate in the aquatic environment of numerous persistent and toxic metals and organic compounds (e.g. pesticides) have given cause for serious concern. Contamination of groundwater resources, or of sediments deposited in riverbeds, impoundment’s and estuaries by toxic and persistent compounds can cause irreversible pollution, sometimes long after the original release to the environment has ceased.
A persistent water quality problem is salination, which has two major causes, natural and anthropogenic. The origin of natural salination of river water is geological. Man-made causes are multiple. A wide variety of man’s activities are associated with increased releases of salts, some in the short and others in the long term. Immediate increases in salt concentrations result from point sources of pollution, such as the discharging of water containing waste by industries. Diffuse pollution, resulting inter alia from poorly managed urban settlements, waste disposal on land and mine residue deposits pose even a bigger problem, as it impacts over a larger area on the water resource. The effect of diffuse pollution on groundwater is also often problematic in terms of remediation.
Another major water quality problem is eutrophication which is the enrichment of water with the plant nutrients nitrate and phosphate. These encourage the growth of microscopic green plants termed algae. As nutrients are present in sewage effluent, the problem is accentuated wherever there is a concentration of humans or animals. The algae cause problems in water purification, e.g. undesirable tastes and odours, and the possible production of trihalomethanes or other potentially carcinogenic products in water that is treated with chlorine for potable purposes.
A water quality issue which is receiving increasing attention among industrialised nations, is pollution by metals and man-made organic compounds, such as pesticides. Serious incidents of health impacts to man and animals have occurred at places throughout the world through uncontrolled exposure to these micro-pollutants. Pollution of this type tends to be highly localised and associated with specific industries or activities. Mining activities often expose pyrite containing rock formations to air and water to produce acid rock drainage. Due to the low pH of acid rock drainage heavy metals are mobilised. The Department of Water Affairs and Forestry has recently established a water pollution control works in the Brugspruit catchment, at huge cost, to treat acid rock drainage emanating from abandoned coal mines.
Water contamination by fecal matter is the medium for the spread of diseases such as dysentery, cholera and typhoid.
Erosion and sedimentation
Average sediment yields for South African catchments range from less than 10 to more than 1 000 tonnes/km2/annum. In some parts of the country erosion has increased by as much as tenfold as a result of human impacts. Apart from the loss of fertile agricultural soil, off-site damage like loss of valuable reservoir storage, sediment damage during floods and increased water treatment costs, have been largely ignored even though these are estimated to be in excess of R 100 million per year.
Source: Dept. Water Affairs
As occasional Acting Water Control Officer (White River Estates Irrigation Board), I have come to realize how important water quality management is on a daily and even on an hourly basis. Water Quality Management in South Africa has become increasingly important as our population skyrockets and our water resources dwindle. Water quality globally and in South Africa has certainly deteriorated due to a number of factors, mostly of human origin. It is critical that our water resources are managed and monitored by qualified, dedicated personnel. Water Scarcity is another severe problem in South Africa. Interpretation and analysis of water quality testing results is another extremely important facet of water quality management.
Rainwater harvesting and greywater recycling can be used as tools to assist water quality management (and reduce water scarcity) through less water entering our stormwater drains and sewage works respectively. Water conservation systems also help to improve water security– an acute problem in South Africa. Water Rhapsody Mpumalanga’s WWF Award-winning water conservation products include water tanks (we are authorized South African JoJo Tank dealers and Atlas Plastics water tank suppliers), rainwater harvesting systems, rainwater tanks, grey water recycling systems, water-saving toilet flush mechanisms, swimming pool backwash recycling systems and other water saving devices. Water and energy are linked and thus we have incorporated Yes Solar Mpumalanga (solar energy is ideal for the Lowveld, with Nelspruit having one of the highest irradiation rates in South Africa!). Yes Solar is an official distributor for German-made Solsquare products that include a wide range of high quality solar panels, solar water heating systems, solar geysers and specific solar solutions customized to your needs. Solsquare solar water geyser systems are Eskom-approved and are installed by Eskom-accredited solar installers (eligible for Eskom renewable energy rebate programme).
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