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GRADE 10 TERM 4 SOCIAL SCIENCES (GEOGRAPHY) UNIT 3: WATER MANAGEMENT IN SOUTH AFRICA

SOURCE 1: What is meant by 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 of 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 meant by 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.

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https://www.dwa.gov.za/dir_wqm/wqm_pollutedwater.htm


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SalinationA 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.

EutrophicationAnother major water quality problem is eutrophication which is the enrichment of water with the plant nutrients nitrate and phosphate. These encourages 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.

Micro-pollutantsA 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.

Microbiological pollutantsWater contamination by fecal matter is the medium for the spread of diseases such as dysentery, cholera and typhoid.

Erosion and sedimentationAverage 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.

Who is responsible for Water Quality ManagementWater Resource Management, including water quality management, is an exclusive National competency. As such, water quality management is the responsibility of the Minister of Water Affairs and Forestry, and the Department of Water Affairs and Forestry’s Water Quality Management function, which consists of the-• Department’s Directorate Water Quality Management, which provides policy development, capacity

building, specialist support, authorization and audit services at a strategic level;• Department’s nine Regional Offices, which provide policy implementation, operation, control and

monitoring services at an operational level; and• Department’s Institute for Water Quality Studies, which provides a scientific support service.


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The capacity of the Department of Water Affairs and Forestry’s Water Quality Management Function will be extended with the establishment of Water Management Institutions, such as the establishment of Catchment Management Agencies within the water management areas of South Africa.

Due to the extent and multiplicity of the management functions associated with water quality management, it is no longer considered to be the sole obligation of a single authority, but is now becoming the responsibility of all levels of the community, including industry, local government as well as individual water users. The most effective “vehicle” for facilitating participatory management, is the Catchment Forum. Through such forums, the public can also be involved in water quality management.

Who is Water Quality being managed for?Being the public trustee of the Nation’s water resources, the Minister of Water Affairs and Forestry and his Department, the Department of Water Affairs and Forestry, has to manage South Africa’s water resources to ensure continued adequate water supplies of acceptable quality to all recognised users. From a water quality management point of view these recognised users consist of, five water user sectors; these being the domestic, agricultural, industrial and recreational water user sectors , as well as the aquatic ecosystem, also constituting the water resource base.

Prominent Legislation application to Water Quality ManagementWater quality management is governed and/ or influenced by a hierarchical suite of environmental legislation, which ranges from-• South Africa’s water resource management

related international obligations, of which Agenda 21 is a prominent example;

• to the Constitution, 1996 (Act No.108 of 1996), constituting the supreme law of the Country and guaranteeing the rights of all people in South Africa;

• to framework environmental legislation, such as the National Environmental Management Act, 1998 (Act No.107 of 1998) [NEMA 107:1998], which had principally been promulgated to enact Sections 24, (environmental rights) and 41 (containing provisions on co-operative governance) of the Constitution;

• through to sectoral environmental legislation, of which the National Water Act, 1998 (Act No.36 of 1998) [NWA 36:1998] is the most prominent example.

Evolution of Water Quality in South AfricaSouth Africa started experiencing environmental pollution problems during the first half of the 19th century, with the development of towns and industries and associated accumulation of wastes in built-up areas. Initially, control of water pollution in South Africa focussed on the development of acceptable sewage disposal methods. Water quality management, however, dates from the promulgation of the Public Health Act of the Union of South Africa, 1919 (Act No.36 of 1919). This Act gave the Chief Health Officer of the Public Health Department the responsibility of controlling pollution by ensuring that the “best known or the only or the most practical methods” for sewage disposal were being used. This allowed the Chief Health Officer to prevent effluent from sewage treatment works from being discharged into water courses. It was a requirement that sewage or sewage effluent had to be disposed on land.



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In moving from the pre-1950 to the post-1950 era, South Africa underwent a change from an agriculturally based economy to one in which industry and mining played a major role. These changes coincided with the evolution from its early beginnings as the Department of Irrigation to the present-day Department of Water Affairs and Forestry. The next major milestone was the promulgation of the Water Act, 1956 (Act No.54 of 1956). The 1956 Water Act aimed at the control of industrial use of water and the treatment and disposal of effluent. By 1956 it was becoming apparent that reconciling water supply with water demand would be increasingly difficult and that re-use of effluent would have to play a major role in the management of the country’s scarce water resources. After 1956 the earlier requirement of the health authorities that prohibited the disposal of effluent to natural water courses had to fall away. The 1956 Act, in fact required that all effluent be returned to the water body from which the water was originally abstracted. Later amendments, notably the Water Amendment Act, 1984 (Act No.96 of 1984) broadened water quality management, and the uniform effluent standards, the General and Special Standards and the Special Standards for Phosphate, were made. The uniform effluent standards approach, however, did not cater for variable circumstances, such as those associated with seasonal changes, or with the different natural and/ or and anthropogenic conditions associated with different catchments.

In order to ensure fitness for use of the country’s water resources, the users’ requirements had to be brought into consideration. This principle resulted in the Receiving Water Quality Objectives (RWQO) approach, which essentially dictates the nature and extent of Source Directed Controls (SDCs) that are required within a catchment context. The South African Water Quality Guidelines, which constitute the primary reference when determining the water quality requirements of water users, were produced as part of the RWQO approach. The water quality requirements of the aquatic ecosystem form part of these.

With the signing into law of the current Act, the NWA 36:1998, in August 1998, the RWQO approach was broadened, introducing the concepts of Resource Quality and Resource Quality Objectives (RQOs). Resource Quality means the quality of all the aspects of the water resource, which includes water quality, water quantity, as well as the aquatic ecosystem quality (quality of the aquatic biota and in-stream and riparian habitat). RQOs are regarded as a

Resource Directed Measure (RDM), which are aimed at the requirements of the water resource. Inherent to this approach, are SDCs that must be established in order to ensure that the requirements that were set during the RDM process, are not violated. The RQOs approach embodies an approach that strives towards a sustainable balance between protection, on the one side, and water use and development, on the other side.

The underlying principles of Water Quality ManagementSustainability, equity and efficiency are recognised as the central guiding principles in the protection, use, development, conservation, management and control of water resources. These guiding principles are inherent to the management of water quality. Water resources must therefore be judiciously managed and equitably shared by all water users in the most optional manner. In water quality management, sustainability means that the protection of water resources must be balanced with its development



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and use. This “balance” is attained through a process of resource classification, the determination of an associated Reserve and the determination of Resource Quality Objectives. Resource Quality Objectives, inter alia, stipulate in-stream water quality objectives aimed at meeting the water quality requirements of the five water user sectors, and are aimed at ensuring fitness for use of South Africa’s surface water, groundwater and coastal estuaries. The concepts of Resource Quality Objectives and Resource Quality that were introduced by the National Water Act, 1998 (Act No. 36 of 1998), necessitate that water quality management, now, also takes responsibility for the management of the aquatic ecosystem quality (in-stream and riparian habitat, and aquatic biota quality).

The following prominent principles form the basis of water quality management policies and practices in South Africa.• The management of water quality must be carried out in an

integrated and holistic manner, acknowledging that all elements of the environment are interrelated.

• Decision-making must ensure that the best practicable environmental option is adopted by taking account of all aspects of the environment including all the people in the environment.

• The precautionary approach to water quality management applies, in which active measures are taken to avert or minimise potential risk of undesirable impacts on the environment.

• In general the principle of Polluter Pays, applies. In accordance with this principle, the cost of remedying pollution, degradation of resource quality and consequent adverse health effects, and of preventing, minimising or controlling pollution, is the responsibility of the polluter.

• Participative management in the management of water quality must be advocated, ensuring that all interested and affected parties, and previously disadvantaged persons have an equal opportunity to participate.

• Transparency and openness must underlie all decision-making processes, and all information must be made accessible in accordance with the law.

Approaches to Water Quality ManagementWater quality management, in South Africa, has evolved from a pollution control approach, which essentially concentrated on source directed management measures, to the current approach where water quality management consists of an integrated source, remediation and resource directed management approach which recognises the receiving water users’, as well as the aquatic ecosystem’s water quality requirements. This water quality management approach is actualised through a combination of measures and arrangements provided for in the National Water Act, 1998 (Act No. 36 of 1998); these provisions including:• The protection of water resources;• the establishment of Water Management Strategies and Water Management Institutions;• the licensing of water use. (Which includes the licensing of discharges through coastal marine

out-fall pipelines to the marine environment);• the implementation of a National Pricing Strategy containing a system of Waste Discharge

Charges; and• the establishment of a National monitoring system and a National information system.



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Resource directed water quality managementIn order to counter the continuing deterioration of water quality and to meet the challenges of the future, the Department of Water Affairs and Forestry has adopted a Receiving Water Quality Objectives approach, consisting of a Receiving Water Quality Objectives approach for non-hazardous substances and a Pollution Minimisation and Prevention approach for hazardous substances.

The Receiving Water Quality Objectives approach for non-hazardous substances accepts that the receiving water

environment has a certain, usually quantifiable, capacity to assimilate waste without serious detriment to the quality requirements of its recognised users. However, if applied without the necessary precaution, the Receiving Water Quality Objectives approach for non-hazardous substances will inevitably lead to the deterioration of water resources to the point where they will be less fit for use by the recognised water user sectors. To counter the limitations of this approach, a precautionary approach was accepted to avert danger and minimise uncertainty and potential risk of undesirable impacts on the environment.

For those wastes that are hazardous and a threat to the environment due of their toxicity, persistence and extent of bio-accumulation, a precautionary approach aimed at minimising or preventing their entry into the water environment, was adopted.

Hierarchy of water quality management decision-taking Decisions in regard to water quality management are made in terms of a hierarchy of principles, which is specifically aimed at marrying the protection, and use and development of water resources. The hierarchy of decision-taking is as follows:

Pollution

Prevention

Principle

Waste Minimisation Principle

Precautionary Principle

Differentiation Principle

Source directed water quality managementWithout efficient and effective source directed controls, the water quality objectives set through resource directed water quality management will, in most cases, not be met. Prior to authorising a license application for a wateruse that may potentially impact on water quality, the applicant must conduct an impact assessment. Such an impact assessment has to demonstrate that the source directed controls proposed, are sufficient to ensure that the water resource remain fit for use by the recognised water user sectors, in accordance with the Receiving Water Quality Objectives approach. Impact assessments must also consider the cumulative effects of actions that in itself may not be significant, but may be significant when added to the impact of other similar actions.



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Catchment Water Quality ManagementThe basic geographical unit of water quality management is the catchment. Water quality management at a catchment scale must integrate land use effects with the physical characteristics of the catchment, and with external factors, such as economics, to manage water quality. Many of these factors have boundaries that are different from the catchment boundaries. Therefore, successful water quality management relies on the integration of these diverse factors into a holistic management system. The aim is continuous improvement of water quality management over time.

Water quality catchment assessment studiesA catchment assessment study entails the assessment of the entire catchment, in which the natural environment and all human activities and impacts on the water resources are investigated. The current status of physical environment, the hydrology, the land-use activities, the demands and the various impacts, impacting on water resources are determined during the study. In addition, to the investigation of prevailing conditions, future developments as well as projected growth and the increase in impacts on the water resources within the catchment are determined. In this way management options that best suit the specific catchment can be developed to ensure sustainable development. Catchment assessment studies contribute to the process of integrated water resources management. The catchment assessment study process requires the engagement and participation of the various stakeholders and institutions in the area, who are interested in water quality, or affected by water quality and the way it might be managed. It follows that one of the best ways of understanding water quality issues in catchments is by engaging the people and institutions who perceive them, or who are affected by them. Such involvement is very often gained through the use of Catchment Forums, which are participatory bodies representing the interests and needs of the stakeholders.

Water quality component of the Catchment Management StrategyThe Catchment Management Strategy (CMS) is a framework strategy for managing water resources within a water management area (WMA) that takes into account all matters relevant to the protection, use, development, conservation, management and control of water resources; and at the same time promotes integrated water resources management. In terms of the National Water Act,

1998 (Act No. 36 of 1998), a CMS must be established for each of the nineteen WMAs in accordance with the requirements of the National Water Resources Strategy (NWRS). The CMS pulls together the water quality, water quantity and aquatic ecosystem components of the water resource into a coherent management approach that aims to secure the beneficial, equitable and sustainable use of water resources. However, while it is important to integrate the management of these, the complexities of the water environment usually demand that they managed somewhat independently at the catchment level. With respect to the water quality component of the CMS, the framework for management is based on identifying the stakeholders’ needs with respect to use of the water resource over and above the requirements necessary for protection, basic human needs and strategic important uses.



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This framework comprises the following:

• establishment of resource water quality objectives for use of the resource, based on the needs of the stakeholders;

• determination of source management objectives to meet these needs;

• formulation of sectoral water quality management plan indicating the management requirements and responsibilities to achieve these objectives;

• development of single source and sector specific water quality management plans to give effect to this framework, and the

• introduction of single source interventions e.g. water use licenses to ensure that resource water quality objectives are met.

Before the framework of the CMS can be developed a catchment assessment study (CAS) is required, as the CAS provides the input information requirements for the CMS. The CAS provides an information and knowledge system suitable for support of development of a CMS, to sustain implementation of a CMS for the catchment and to support source specific management interventions.

Water Quality Management InstrumentsEssentially, water quality management employs a combination of the four environmental management instruments, viz.: the regulatory, market-based, self-regulatory and civil management instruments.

Regulatory management instrumentsWater use, and impacts on water quality are regulated through a range of authorisations, which are either being directly managed by the Department of Water Affairs and Forestry, or in co-operation with other government departments, e.g.:

• Licensing of water use that may have, or may potentially have an impact on water quality in terms of Section 40 of the National Water Act, 1998 (Act No. 36 of 1998);

• issuing of disposal site permits in term of Section 20 of the Environment Conservation Act, 1989 (Act No. 73 of 1989);

• recommendation for approval of Environmental Management Programs (EMPs) in terms of Section 39 of the Minerals Act, 1991 (Act No. 50 of 1991) to the Department of Minerals and Energy; and

• recommendation for approval of Environmental Impact Assessments (EIAs) in terms of Sections 21, 26 and 28 of the Environment Conservation Act, 1989 (Act No. 73 of 1989) to the Department of Environmental Affairs and Tourism.

Market-based management instrumentsIn water quality management the Pricing Strategy, which includes a system of waste discharge charges, makes provision for certain incentives which has as its aim-

• the introduction of new technologies or management practices;

• the conservation and the economically efficient allocation of scarce water resources;

• the removal of elements of waste streams



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Self-regulatory management instrumentsThe ISO 14000 series of environmental standards provides a range of self-regulatory management instruments, which can be utilised by industry to improve their environmental performance. The only component of the ISO 14000 series of environmental standards that is required for certification at the moment, is ISO 14001. Before an organisation can obtain ISO 14001 certification, it must, amongst others, have considered all legal requirements. In promoting ISO 14001 certification, the Department of Water Affairs and Forestry will be able to extend its water quality management capacity.

Civil management instrumentsThe National Water Act, 1998 (Act No. 36 of 1998) requires where appropriate the delegation of management functions to a regional or catchment level so as to enable everyone to participate. The importance of public participation is further emphasised by the National Environmental Management Act, 1998 (Act 108 of 108) which lays down the principle of transparent and participative management for co-operative environmental management. A consequence of this decentralisation of decision-making requires the establishment of catchment based institutions such as Water User Associations and Catchment Management Agencies to ensure public participation. Within water quality management, catchment forums have provided an ideal mechanism to facilitate the involvement of stakeholders in decisions affecting their water quality. Catchment forums serve as suitable platforms for efficient and coherent participation of stakeholders with diverse interests.

Co-Operative Governance in Water Quality ManagementCo-operative Governance and participative management is central to the Department of Water Affairs and Forestry’s water quality management approach, and provides for integration across a number of dimensions. In its management of water quality, the Department advocates the principle of participative management by involving other government departments and local interested and affected parties in decisions affecting the use, development and protection of water resources. By means of such integration the socio-economic needs and

that of the environment are accounted for, allowing for sound and holistic decision making that ensures minimal impact on water quality. Such co-operative environmental governance is facilitated by means of catchment forums, which serve as institutionalised mechanisms to involve stakeholders in decisions about water resources management.

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Orange River Water SchemeHistory of the Orange River ProjectThe Orange River and its major tributary, the Vaal River, convey nearly 23 % of the total surface water of South Africa. Considering the generally dry climatic conditions characterising the sub-continent, it is essential for this fresh water resource to be utilized to the greatest benefit of the country and its people, including those of Namibia.

The pioneer in the development of the water resources of the Orange River was Dr AD Lewis, one of the first administrative heads of the then Department of Irrigation (now the Department of Water Affairs and Forestry). As a result of recurring droughts in the Eastern Cape, Lewis, as early as 1928, broached the idea of building a tunnel from a point near Bethulie underneath the Suurberg Plateau to convey Orange River water via the Teebusspruit and the Brak River to eventually reach the Great Fish River valley.

This concept was followed up in 1944 when field surveys and drilling were initiated. This resulted in a report to the Government in 1948 which proposed a project comprising amongst others, a diversion dam on the Orange River as well as a diversion canal and tunnel underneath the divide to the Great Fish River valley, with a branch canal to the Sundays River valley. The first White Paper on the project was tabled in Parliament in 1951 and the actual development was started soon thereafter.

The developments associated with the Orange River are currently spread over six of the nine provinces of the country, namely Northern Cape, North West, Gauteng, Orange Free State and Eastern Transvaal. Orange River water currently supplies water to consumers in an area from Bloemfontein in the East to Port Elizabeth in the South and Alexander Bay at the river mouth in the West. The first water from the Lesotho Highlands Water Project was transferred to the Vaal River basin in October 1997 for testing purposes and the first main supplies are scheduled for 1998.

The Orange River ProjectAs a result of the population explosion and accompanying development, the country’s needs, including the demand for water, are continually increasing.

A project initially referred to as the Orange River Project was developed to utilize the water of the Orange River for extensive irrigation schemes, for the generation of hydro-electric power and for urban supply, thus providing for the increasing demand for water and food. The developments that have taken place in the Orange River basin are now so complex and inter-dependent that the term Orange River Project is no longer used although much of the earlier documentation and White Papers still refer to it.

The original main aims of the ORP were:-• to make provision for new irrigation development along the Orange River and various other areas

within reach of the river;• to stabilize the water supply to existing irrigation schemes;• to afford new life to the fertile but water-deficient Great Fish River and Sundays River valleys;• to supply water to various urban centres; and• generate hydro-electric power.

The project would thus:-• increase the value of the South African agricultural production;• make provision for the establishment of a large number of irrigation farms;


https://www.dwa.gov.za/orange/Mid_Orange/orange-f.htm


https://www.dwa.gov.za/orange/Low_Orange/alexande.htm

https://www.dwa.gov.za/orange/Up_Orange/lhwpover.htm


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• stimulate the production of meat, wool, milk, lucerne, cotton, wheat, raisins, dried beans and peas, both in the Orange River basin and elsewhere;

• promote economic activity and development in the areas directly involved;• counteract the migration of the rural population to the cities by creating stable farming

communities;• create recreation facilities in the centre of the interior and promote tourism;• level off moderate flood peaks in the course of the river and in the process safeguard riparian

communities and irrigation schemes downstream.

Since 1961, the objectives and the planning of the project have been reviewed from time to time due to the changing circumstances and priorities within the Orange River basin and surrounding catchments. Such replanning is normal for a large project of this nature which is developed over a number of decades.

Further planning of the ORP was undertaken to evaluate the water requirements and available resources in the Orange River as well as the impact of the Lesotho Highlands Water Project on these resources. In this regard, a full system analysis of the Orange River was started in 1987 and completed in 1993. This initial study was called the Orange River System Analysis was subsequently updated by the Orange River Replanning Study which was started in 1994 and completed in 1998. Further studies are continually being carried out to investigate specific development options in a continuous effort to plan the efficient use of Orange River water. The quantity of water available for development in the orange River is constantly being assessed and other aspects such as the influences of further developments on the water quality and environment are also being analysed.

Main Features of the ORPA summary of the main features of the Orange River Project are given below. Details of each component can be found in the relevant section by simply clicking on the component of interest.

• Gariep Dam

• Vanderkloof Dam

• Welbedacht Dam

• Knellpoort Dam

• Novo Transfer

• Orange/Vaal Scheme

• Vanderkloof Canal System including:-• Ramah Branch Canal• Orange-Riet Canal

• Kakamas Betterment Works and Extensions

• Orange-Fish Tunnel

• Cookhouse Tunnel

• De Mistkraal Weir

• Darlington Dam

• Lower Sundays River Scheme

• Lower Fish River Scheme

For further information on the links above visit: https://goo.gl/VykvAH



https://www.dwa.gov.za/orange/mid_orange/gariep.htm

https://www.dwa.gov.za/orange/Mid_Orange/vanderkl.htm

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Tugela-Vaal Water SchemeSterkfontein Dam is situated in the very upper reaches of the Vaal Dam catchment on the Nuwejaarspruit, a few kilometres from the edge of the Drakensberg Escarpment. It has a very small catchment area with negligible natural inflow with the result that it requires no spillway. It was commissioned in 1977 and comprised a 69m high earthfill embankment, 2 290m long with no spillway. It was subsequently raised in 1980 to its current height of 93m with a crest length of 3 060m and a full supply capacity of 2 656 Ml. It has a surface area of only 70km2 which makes it a highly efficient storage unit.

A small section of the Sterkfontein Dam reservoir is cut-off by the construction of Driekloof Dam which forms a small reservoir with a capacity of 35.6 million m3. This reservoir forms the upper storage reservoir for the Tugela-Vaal pumped storage scheme and is connected to the lower storage reservoir of Kilburn Dam located some 500 meters below in the Tugela catchment.

Water is pumped up from Kilburn Dam at a rate of 174m3/s by four 250MW pump/turbines into Driekloof Dam during period of low power demand. During period of peak demand, typically during the morning and early evening, the water is released from Driekloof Dam at a rate of 312 m3/s to generate up to 1 000 MW of power. The scheme is operated in such a way that there is a net pumping of up to 630 million m3/annum depending upon the water availability in the Tugela catchment (Woodstock Dam) as well as the need for augmentation in the Vaal Dam catchment.

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The Tugela-Vaal Transfer SchemeThis scheme is found in the Drakensberg and was completed in 1974. The Tugela River starts at Mont Aux Sources, in the Drakensberg, and naturally flows through KwaZulu-Natal into the Indian Ocean. With the construction of the Tugela-Vaal Transfer Scheme, a certain amount of the water from the Tugela River is transferred via canals, pipelines and dams into the Vaal River system.

The Tugela River flows into the Woodstock Dam (Surface Area: 29 square kilometres; Average Depth: 40 metres; Total Storage Capacity: 380 million cubic metres) and then into the Driel Barrage further downstream. A certain amount of water is pumped from the Driel Barrage into canals which then flow via gravity into the Kilburn Dam. Water from the Kilburn Dam is then pumped underground, over the Drakensberg (500m), and into the Driekloof Dam.

This section of the scheme is used to generate electricity as a hydroelectric power station has been built within the mountains of the Drakensberg. This power station, known as the Drakensberg Pumped Storage Scheme, is managed by Eskom and electricity that is produced here is fed into the national electricity grid.

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Lesotho Highlands Water ProjectLesotho Highlands Water Project, LesothoThe award-winning, multibillion Rand, bi-national Lesotho Highlands Water Project (LHWP) is widely regarded as an African success story. It has pioneered the way for peaceful cooperation and mutually beneficial socio-economic development across the continent. Aurecon has played various key roles in the project since its inception six decades ago.

In 1986, the Kingdom of Lesotho and the Republic of South Africa signed a treaty to harness the water resources of the Lesotho Highlands to supply water to South Africa and generate power for Lesotho.

Phase 1 of the project comprised the major water transfer and hydropower components involving the construction of tunnels and dams, including the iconic 185 m high Katse Dam, designed to divert water from the Senqu (Orange) River to the Ash River in South Africa.

Some of the challenges of the project included overcoming the large-scale, technically complex nature of the water transfer project, working in a harsh mountain environment and pioneering new systems to manage the biophysical and social challenges of the project.

In 2005, a Phase 2 feasibility study was undertaken in two stages aimed at identifying further development options and investigating the preferred option in detail, which culminated in the recommendation of the Polihali Dam and transfer tunnel for implementation. Procurement of consulting services for the implementation of Phase 2 is currently underway.

The LHWP is one of the largest ongoing development projects in the world. In 2006, the South African Institution of Civil Engineering (SAICE) named the LHWP as the Most Outstanding Engineering Achievement of the Century.

https://goo.gl/KcaFB9

Refer to: https://goo.gl/62Xtkx for more information


http://www.aurecongroup.com/en/expertise/water-resources-management.aspx

http://www.aurecongroup.com/en/expertise/power-generation.aspx

http://www.aurecongroup.com/en/markets/water.aspx

http://www.aurecongroup.com/en/markets/water.aspx

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Breede-Berg Water Transfer SchemeWESTERN CAPE WATER SUPPLY SYSTEM AUGMENTATION PROJECT

INTRODUCTIONThe Western Cape Water Supply System (WCWSS) serves the City of Cape Town and surrounding smaller towns and irrigators. It consists of infrastructure components owned and operated by both the City of Cape Town and the Department of Water and Sanitation.

The Department of Water and Sanitation undertook the Western Cape Water Supply System Reconciliation Strategy Study which investigated a range of bulk water supply schemes that could serve towards meeting the growing water requirements that will need to be supplied from the WCWSS. These included options such as desalination of sea water, water re-use, groundwater development and possible surface water augmentation options along with water conservation and water demand management. The Reconciliation Strategy Study identified the need for augmentation of the WCWSS by 2019.

The Reconciliation Strategy Committee made the decision that the Department of Water and Sanitation would investigate the surface water augmentation options while the City of Cape Town would investigate the other options.

Following on the recommendations of the Reconciliation Strategy, the Department of Water and Sanitation commissioned a detailed Feasibility Study to investigate the identified surface water development options. The first phase involved a pre-feasibility assessment of each of the six potential surface water development options in order to select the two most viable options for further investigation to feasibility study level in the second phase of the Feasibility Study. The two most viable schemes identified were as follows:

Berg River – Voelvlei Augmentation Scheme (BRVAS); and

Breede – Berg (Michell’s Pass) Water Transfer Scheme, abbreviated as the Breede – Berg Transfer Scheme (BBTS).



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Both schemes rely on the utilisation of the existing storage capacity in the Voëlvlei Dam, and on the existing capacity of the City of Cape Town’s pipeline, from their water treatment works at the dam, to their Plattekloof reservoir in Cape Town.

DESCRIPTION OF THE SCHEMEThe Berg River – Voëlvlei Augmentation Scheme has been found to be the favourable surface water intervention option, albeit only able to augment the Western Cape Water Supply System by about 2 to 3 years. It is an option that will be considered within the current planning horizon of the Western Cape Reconciliation Strategy as the next possible surface water intervention. A comparative analysis will be required between the preferred surface water development option and the best of the other options investigated by the City of Cape Town.

Apart from having a favourable Unit Reference Value (a measure of unit cost), the BRVAS also has the advantage that it is likely to be the only scheme that could be implemented by about 2018/19 when the growth in water requirement may exceed the existing yield of the system.

The proposed scheme would involve the pumped abstraction of winter water from the Berg River, once the ecological water requirements of the river and the estuary have been met. The ecological Reserve commensurate with a Category D River has been allowed for in the system modelling of the scheme.

According to the Reserve for the Berg River Estuary the required stream flow into the estuary during the summer months should vary between 0.6 and 0.9 m3/s. As the present day inflows into the estuary are not gauged (although DWS has plans to install a gauge), the present day inflow of 0.3 m3/s was estimated from the gauged flows below Misverstand Dam, and from the downstream irrigation allocations which will be metered in the near future. In order to provide the required Reserve inflows to the estuary would require that additional releases of between 0.3 m3/s and 0.6 m3/s should be made from Voëlvlei Dam, particularly during the four summer months from December to March. Therefore, the conservative assumption has been made in the system modelling of the proposed scheme that an additional release of 0.5 m3/s should be made from Voëlvlei Dam for the six summer months.

Two scheme options have been investigated, namely:• Option 1 for a 4 m3/s pump station with a stepped-pump operating rule.• Option 2 for 6 m3/s pump station with variable speed drives.

Location of the Berg River – Voelvlei Augmentation Scheme

CONCLUSIONS AND RECOMMENDATIONSThe following conclusions and recommendations are made in relation to the potential implementation of the Berg River – Voelvlei Augmentation Scheme:

The Berg River Reserve commensurate with a Category D River has been allowed for, and a recommended minimum summer low flow for the estuary of 0.6 m3/s, of which 0.5 m3/s (8 million m3/annum) would be provided out of releases from the Voëlvlei Dam to supplement the present day inflows (which are ungauged) into the estuary. The proposed scheme will need to comply with the requirements of the relevant legislation, including but not limited to: (a) National Environmental Management Act, (b) National Heritage Resources Act, and (c) National Water Act.

The proposed Lorelei abstraction site is close to a bend on the Berg River which is favourable from a sedimentation management perspective. Geologically this is the only location of those considered at which any rock outcrop is evident for suitable founding conditions. From a hydraulic and geotechnical perspective this site is therefore recommended as the preferred location for the abstraction weir.



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The Lorelei site also has the shortest conveyance length of all abstraction site options considered and enables the rising main to the Voëlvlei Dam to be aligned such that the least possible impact is made on the Renosterveld within the Voëlvlei Conservancy.

Of the two potential abstraction approaches investigated in detail, namely a 4 m3/s pump station with a stepped-pump operating rule, or a 6 m3/s pump station with variable speed drives, the former appears to be more easily implemented and operated, as well as offering a slightly higher resulting yield (23 versus 20 million m3/a). From an operational perspective, the 4 m3/s abstraction via a stepped-pumping operating rule is recommended.

Suitably accurate survey information is available from the Feasibility Study for the purpose of undertaking detailed design of this scheme.

Geotechnical conditions at the Lorelei site are generally favourable, and the weir design can be suitably accommodated at the proposed site. Machine excavation is expected to be possible along the pipeline route. Although there is potential for the use of excavated materials for backfilling, the final pipe type selection will influence the extent of selected fill material available in-situ.

For the 6.3 km rising main, a 1700 mm diameter GRP is proposed for the 4 m3/s abstraction option and the same pipe type (1900 mm diameter) for the 6 m3/s option.

The estimated capital cost of the 4 m3/s abstraction option is R277 million and that of the 6 m3/s option R 312 million including VAT. The corresponding Unit Reference Values are R1.52/m3 and R1.94/m3 respectively for a discount rate of 8% per annum, and based on the VAT exclusive costs. On the basis of the financial assessment, technical and environmental considerations, the 4 m3/s option is recommended.

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