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This case study describes the water quality management approach of the Department of Water Affairs and Forestry DWAF to ensure that the surface water quality in the Witbank Dam remains f

Case Study V* - The Witbank Dam Catchment

* This case study was prepared by S.A.P Brown

V.1 Introduction

The Witbank Dam catchment is located in the upper portion of the Olifants River basin The Olifants River is one of South Africa's major water resources The water quality in the Witbank Dam catchment is rapidly deteriorating, mainly due to coal mining If this trend were to continue, the water in the Witbank Dam would be unfit for use, for most of the recognised users, by the end of this century Poor water quality in the dam has meant that power generation, which is the largest industrial activity in the catchment, already has to rely largely on other sources of water from outside the catchment

This case study describes the water quality management approach of the Department of Water Affairs and Forestry (DWAF) to ensure that the surface water quality in the

Witbank Dam remains fit for use and that the resource is secured adequately for the future Many aspects of this approach are currently still being implemented

Nevertheless, further deterioration in water quality has been arrested and has been evident since October 1993 (see Figure V.3) Indications are that the implementation of this approach will result in water fit for use in the Witbank Dam catchment for at least the next 10 years Other strategies will have to be employed to address water quality in the longer term

V.2 Background information

South Africa is a country of great diversity Its society comprises underdeveloped,

developing and developed components The annual disposable income per capita for all population groups is approximately US$ 2,000, but varies between US$ 1,020 and 7,750 for different population groups Furthermore, the country is characterised by great

disparities concerning access to adequate water supplies Water-related issues are, therefore, a central aspect in the country's political arena; so much so that water supply and sanitation for all the inhabitants of South Africa is a key element of the

Reconstruction and Development Programme (RDP) This programme was initiated by the Government of National Unity to restore the social and economic imbalances in the country

Figure V.1 Location map of South Africa showing the Olifants River basin and the Witbank Dam catchment

South Africa is, however, a semi-arid country with limited water resources Water is geographically unevenly distributed throughout the country and is not consistently

available throughout the year Generally, more water is available in the eastern portion

of the country and availability gradually declines westwards The Olifants River, one of South Africa's major water resources, is situated towards the east The availability of water is further compounded by the fact that the demography of the South African

population is changing rapidly Vast numbers of people are moving to cities where they live in areas of poor water supply and sanitation services, or none at all

The DWAF is the authority, in South Africa, responsible for overall water resource

management and it has to ensure the supply of adequate quantities of water of

acceptable quality to recognised water users However, in practice, part of this

responsibility is delegated to other levels of government, other agencies, water users and to those who have an impact on the water resource As a result of the dynamic political situation in South Africa, roles and responsibilities are being redefined and reallocated In carrying out its mandate, DWAF often has to reconcile, integrate and co-ordinate conflicting and diverse interests within the framework of sustainable and

equitable use of South Africa's water resources

Figure V.2 Detailed map of the Witbank Dam catchment and its nine management units, showing urban development and major industrial and mining activities (After Wates, Meiring and Barnard, 1993)

V.3 The Witbank Dam catchment

The Witbank Dam catchment is located at the headwaters of the Olifants River (Figure V.1) A more detailed representation of the catchment is provided in Figure V.2 which indicates the location of Witbank Dam, urban development and major industrial and mining activities, as well as the nine management units (see section V.5.1) The Witbank Dam catchment covers an area of 3,256 km2 and has a mean annual run-off of 125 × 106

m3 a-1

Land-use practices in the catchment are varied and include the following:

• Agriculture, of which maize is of strategic importance to South Africa's national staple food supply Dry-land cultivation of maize is practised on 24 per cent of the catchment area

• Power generation, which is the largest industrial activity in the catchment and includes four of the country's major coal-fired power stations

• Coal mining A total of 29 major collieries and a number of smaller operations are active in the catchment, producing approximately 47 per cent of the country's coal production

• Urban development, which is limited to a number of smaller towns

V.4 Pre-intervention situation

V.4.1 The strategy

The general approach to pollution control and environmental management in South Africa entails a management strategy based on a single environmental medium which is either air, water or land The regulatory authorities responsible for the management of the environment are organised as follows:

• Air: Department of National Health

• Water: Department of Water Affairs and Forestry

• Land: Department of Agriculture together with various other Departments For example control over mining activities is exercised by the Department of Mineral and Energy Affairs (DMEA)

The three main regulatory authorities have developed different organisational structures

to suit their regulatory approach Furthermore, the present arrangement fails to

recognise the transfer of pollution across environmental boundaries It also does not provide for a regulatory mechanism to ensure that environmental management is

effective and efficient The result is the absence of clear responsibilities, the overlapping

of institutional boundaries, the exclusion of areas which require attention and a

duplication of effort

Prior to 1991, the water quality management strategy of DWAF was based on the

Uniform Effluent Standards (UES) approach In applying this strategy, the focus was mainly on point source effluents Diffuse sources of water pollution and the receiving water body were not given the necessary attention With respect to control over mining activities, these shortcomings were further compounded by several factors:

• The DWAF addressed water quality management concerning mining in isolation, i.e control of water quality in relation to mining activities was not integrated with other activities This approach even included separate offices dealing with mining-related matters within the same management area

• There was a lack of co-ordination between DWAF and the DMEA which has the

primary responsibility regarding the influence of mining activities on land use

• The mining community was not aware of the detrimental effect of coal mining on the water environment

V.4.2 Water quality issues

Coal mining is a major potential source of diffuse water pollution Sulphate is a good indicator of salinity arising from this form of pollution Approximately 70-80 per cent of the sulphate load in the Witbank Dam catchment emanates from diffuse sources and can be attributed to coal mining This increase in diffuse pollution has resulted in a gradual decline in water quality in the Witbank Dam catchment Water quality in the dam itself has declined from 50 mg l-1 sulphate and 100 mg l-1 total dissolved solids (TDS) to over 150 mg l-1 sulphate and 400 mg l-1 TDS The concentrations of these two variables over a 16-year period are given in Figure V.3 In some reaches of rivers and streams in the catchment this deterioration has been more pronounced and, in some cases, water quality has deteriorated from a natural baseline level of approximately 50 mg l-1 to over 1,500 mg l-1 sulphate

The other major water quality issues are:

• Eutrophication Phosphorus is the limiting nutrient in the dam and the concentration of total phosphorus has not changed significantly over the past decade However, the transparency of the water in the dam has increased by an order of magnitude over the same period of time This is mainly due to the increase in TDS which has enhanced the flocculation of clay particulates resulting in an increase in light penetration

• Elevated levels of compounds toxic to the natural aquatic environment occur in some reaches of streams in the catchment These compounds are predominantly metals and ammonia Acid mine drainage associated with coal mining mobilises metals Aluminium, iron and manganese are the main metals of concern Ammonia originates from sewage effluents

V.5 Intervention with a new approach

During 1991, DWAF adopted a new water quality management strategy This strategy focuses on the receiving water body and considers all sources of water pollution

Catchment water quality management plans and sectoral specific management

strategies are central to the new strategy As part of this strategy, the water quality management approach in the Witbank Dam catchment was reviewed The aim of the new approach is to arrest deterioration of water quality, to ensure fitness for use by the recognised water users and to secure the water resource The main thrust of this

approach consists of:

• Development and implementation of a catchment water quality management plan

• Prevention and minimisation of pollution arising from mining activities wherever

possible

These two activities are inter-related and are implemented concurrently The catchment water quality management plan has to provide, amongst other things, compliance

requirements for each activity based on the level of pollution that can be accommodated

by the water without impairing its suitability for use Pollution prevention is a key issue in the catchment strategies embodied in the management plan to ensure that set water quality management objectives are met

Figure V.3 Total dissolved solids and sulphate concentrations in Witbank Dam,

1987-94 (After Wates, Meiring and Barnard, 1993)

V.5.1 Catchment water quality management plan

A catchment plan will provide a framework to manage water quality coherently and consistently; to influence present and future land use, particularly those uses over which DWAF does not have direct control; and to integrate other resource management efforts and environmental media issues with water quality In order to provide this framework, the following steps were taken:

• Water quality objectives were set at strategic locations in each catchment The water quality objective at a particular location is a quantitative statement of the water quality that must be maintained at that particular point to ensure suitability for use In the

Witbank Dam catchment, the recognised water uses are domestic, power generation, mining, recreation, the natural aquatic environment and irrigation

• Flexible catchment strategies were formulated to ensure that water quality objectives can be attained

• Compliance requirements were set for those activities that could adversely affect water quality Sites giving rise to both point and diffuse sources of pollution were considered

"single" sources and the compliance requirements were determined and stipulated accordingly

• The collective powers and influence of other authorities, agencies and the public were co-ordinated in a co-operative manner to implement catchment strategies This applies particularly to control over future land use and adjustment to existing land-use practices

to reduce diffuse sources of water pollution

• Monitoring and auditing systems were provided to ensure the implementation of

catchment strategies The effectiveness of the catchment water quality management plan and of water quality management efforts undertaken by other role-players was also monitored

The catchment water quality management plan is being developed to such a level of detail that it specifies what must be achieved and implemented, where and when it will

be implemented, how it will be administered and managed and who will be responsible for the specific activities However, the catchment cannot be managed as a single

management unit Sub-catchments upstream of the dam have different water-use

requirements For this reason, the catchment was subdivided into nine management units on the basis of the sub-catchments (see Figure V.2) At the lower end of each management unit, in-stream water quality management objectives are set

The management strategies and water quality objectives embodied in the plan focus on:

• Salinity, with sulphate as the selected indicator of salinity

• Eutrophication, with phosphorus as the limiting nutrient

• Toxic constituents, particularly heavy metals and ammonia

Salinity

The sulphate management objective for the dam itself was set at 155 mg l-1 (95

percentile value) This is approximately 23 per cent lower than the user requirement of

200 mg l-1 This margin allows for:

• Further mining, industrial and agricultural development

• Potential malfunctioning of water pollution control systems

• Current knowledge gaps on the future potential impact of atmospheric deposits, high- extraction coal mining and open-cast mining technique

• Lack of adequate information to establish accurately water user requirements,

particularly that pertaining to the natural aquatic environment

Attainment of the sulphate management objective depends on zero discharge from power stations, 45 per cent reduction in diffuse pollution from collieries and additional water imported into the catchment The projected improvements resulting from applying

these strategies are indicated in Figure V.4 The sulphate management objectives for the nine management units are outlined in Table V.1

Figure V.4 Present and predicted sulphate concentrations in Witbank Dam assuming power stations operating at zero discharge facilities and with a 45 per cent reduction in non-point source colliery pollution (After Wates, Meiring and

Barnard, 1993)

Eutrophication

Eutrophication control is aimed at limiting the available phosphorus compounds in order

to reduce algal growth in the Witbank Dam Natural anthropogenic weathering and agriculture are the largest diffuse sources of phosphorus in the catchment Substantial losses of phosphorus applied to agricultural land take place in the catchment; 32 per cent of this reaches the Witbank Dam It was not considered practical to control these diffuse sources of phosphorus Municipal sewage treatment plant effluents provide 38 per cent of the recorded catchment sources and 44 per cent of the recorded phosphorus discharge to the dam Phosphorus control is principally aimed at these sources by means of imposing a special phosphate standard of 1 mg l-1 PO4-P on all sewage plant effluents

Table V.1 In-stream sulphate management objectives

Management objective Management unit1

Most sensitive user requirement (mg l-1

Source: Wates, Meiring and Barnard, 1993

Metals and ammonia

Control of metals and ammonia will be effected by restricting the maximum allowable

free and saline ammonia and metal concentrations in discharges from mining and

industrial complexes These maximum allowable concentrations are given in Tables V.2

and V.3

V.5.2 Prevention and minimisation of pollution

The essence of the approach to pollution prevention and minimisation is the use of

regulatory instruments which facilitate direct intervention to prevent pollution at source

The Water Act, which is the statutory component of the regulatory instruments applied

by DWAF directly, has limited power to exert influence on land use affected by mining

Thus direct intervention to prevent diffuse pollution, in particular, is not always possible

In order to address this, as well as other shortcomings mentioned earlier in relation to

mining activities, co-ordination between the regulatory systems of DWAF and DMEA

was effected Co-ordination was accomplished by participation within an integrated

environmental management system for prospecting and mining activities

Table V.2 Maximum allowable concentrations of free and saline ammonia in discharges

from mining and industry

Free and saline ammonia concentration (mg l-1

requirement has been applied to discharges

Source: Wates, Meiring and Barnard, 1993

Table V.3 Maximum allowable concentrations of heavy metals in discharges from mining

and industry

Heavy metal Maximum allowable concentration (mg l-1

)Aluminum 150

Source: Wates, Meiring and Barnard, 1993

The integrated system plays a key role in the regulatory systems of both departments in the following ways:

• Placing the departments in a position to address anticipated effects on the water environment before mining proceeds

• Placing the departments in a position to ensure that environmental objectives are met constantly

• Ensuring that mining proponents have understood the magnitude and nature of the effect which their activities will have on the environment, and have committed

themselves to a practical means of dealing with these effects before commencing a mining venture

• Providing the authorities with an opportunity to satisfy themselves that the proponents have the means to ensure that the management measures proposed to control the

environmental effect of their activities will be implemented

In order to fulfil the requirements of the integrated management system, each mine in the catchment has to carry out the following:

• Implement an approved Environmental Management Programme, pertaining to a

particular mine, that explicitly prescribes measures necessary to prevent and minimise pollution

• Implement adequate measures before closure to prevent pollution and to provide for sustainable use of the water resource

• Only discharge polluted water from point or diffuse sources in accordance with the conditions prescribed by DWAF

• Make adequate financial provisions to ensure that the impact management measures planned can be implemented

V.6 Shortcomings of the approach

Various shortcomings were identified as a result of the experience gained during the development and implementation of the water quality management approach in the

Witbank Dam catchment The following issues require attention:

• The development of a catchment plant that focuses on water quality alone serves a limited purpose Water supply and demand issues must be included in the development

of a catchment water management plan to ensure effective water resource management

• Commitment to water-related issues are currently voluntary, particularly those outside the direct influence of the Act administered by DWAF In most cases, these pertain to influence on land use which is crucial to the success of a plan Mechanisms have to be established to ensure that commitments are fulfilled Some of these will be addressed by amendments to the Water Act envisaged in the near future

• The institutional capacity of the DMEA particularly needs to be improved This

department, the lead agency in the implementation of the integrated management

system for prospecting and mining, has shown shortcomings with respect to its

awareness of the needs of the water environment, and with respect to managing a

complex system, such as the integration system for prospecting and mining

• Participation of stakeholders must be ensured right from the initiation of the

development of a catchment water quality management plan In the case of the Witbank Dam plan, the technical aspects were developed with limited participation It became clear recently that, for this reason, difficulties could be experienced with the

implementation of the plan Stakeholders do not feel they have "ownership" of the plan,