The goal for water resource management and service provision in South Africa is captured in the succinct statement "Some, for all, forever". This provides the context and motivation for the protection of water resources:

If water, and the services provided by water resources, are to be available to people on an equitable basis in the long term (forever), then water resources require protection. This policy is founded on, and guided by the Water Law Principles accepted by the South African Cabinet in November 1996.

We have been used to thinking about water as a commodity, something which is contained in rivers, lakes and groundwater, stored in dams and reservoirs, transported in pipes and canals, and purchased for various uses and services, such as drinking water, irrigation or industrial processes. We need to broaden our view, and see that in fact, the water itself is only one part of a large and complex ecosystem. It is this larger ecosystem which provides us, not only with the water which we see as a commodity, but also with many other services and benefits.

• water for drinking and basic human needs;
• water for economic development (for example industry, agriculture, power generation);
• transport and/or purification of some waste products;
• subsistence or commercial supplies of fish and plants;
• opportunities for recreation;
• maintenance of habitats for conservation of particular plants, animals, landscapes and environments, for conservation of biodiversity, and for utilisation such as ecotourism;
• retention and storage of water;
• transport of flood waters.

Almost all of the services provided by utilisation of water resources rely on natural hydrological, biological and ecological processes, and require at least some degree of maintenance of the natural structure and character of aquatic ecosystems. As "renewable natural resources", water resources have a certain amount of resilience to the pressures and demands of utilisation. This resilience allows water resources to be utilised on a continuous basis, as long as the demands are not too great.

If a water resource is over-utilised or allowed to degrade too far, (ie too much water is taken out, too much waste is put in, natural shape and structure are modified too greatly by erosion, sedimentation or habitat degradation), then the water ecosystem loses resilience and begins to break down. The ecological integrity of the resource can be damaged: once this happens, the capability of the resource to meet people's demands for utilisation can be reduced, or possibly even lost altogether. If the utilisation of water resources remains at a level within the limits which can protect ecological resilience, then that level of utilisation can be sustained indefinitely.

In many cases in South Africa, our water resources have already been modified by utilisation and development, and no longer remain in their natural ecological state. A water resource does not have to be in a pristine or untouched state to have ecological integrity; even modified aquatic ecosystems can have the resilience which makes them renewable resources, so long as we manage them in such a way that we either maintain or rehabilitate a certain level of ecological function and integrity.

The fact that water is a renewable natural resource means that we need to change the way in which we perceive and value our water resources. This new perspective has two major implications for water resource management. First, we need to see a water resource not just as the commodity water, but as the whole ecosystem, of which water is one component. The ecological integrity which gives a water resource its resilience is an essential component of the value of the resource. This leads us to a new and broader definition of a water resource:

Second, we need to recognise and respect the limits to the degree of utilisation which can be sustained by a water resource before resilience is lost. Resilience in turn depends on maintaining a certain base level of ecological integrity and function. This level, which we call the Resource Base, is critical to the capability of water resources to sustain utilisation, and must be protected.

In recognition of the importance of the Resource Base, the Water Law Principles identify a "Reserve", which will give effect to the policy for protection. The Reserve is intended to protect the resilience of water resources, in order that basic human needs can be met (eg human health and safety and domestic water supply,) and ecological functions and processes can be sustained.

In order to reflect a new and broader perspective on water resources, the term "water resource quality" is used, rather than simply "water quality." This is a reminder that all components of aquatic ecosystems - the water environment - must function properly if we are to reach the goal of "some for all, forever."

The responsibility for management of water resources includes a responsibility to protect the users of water resources, which in turn requires protection of water resources from over-utilisation or impacts which cause degradation.

• protection to ensure sufficient water quantity and water quality (especially in relation to human health), to meet basic human needs;
• protection of ecosystem structure and function, in order to ensure that utilisation of water resources can be sustained in the long term;
• meeting the water quality requirements of other water users (agriculture, industry, recreation) as far as possible, within the constraints of requirements for protection of basic human needs and protection of the resources.

Sustainable utilisation requires achievement of a balance between an acceptable level of long term protection of water resources and water users, and society's present requirements for economic growth and development. The total prevention of pollution, while an ideal for which to strive in the long term, is not practical in the short to medium term, since neither the emission of waste to the water environment, nor the impacts of land uses on the water environment, can be prevented entirely. However, they can and must be managed and regulated to achieve adequate long term protection of water resource quality. This is the aim of the resource protection policy.

• resource-directed measures, ie defining a desired level of protection for a water resource, and on that basis, setting clear numerical or descriptive goals for the resource quality of the resource (the Resource Quality Objectives);
• source-directed controls, ie controlling impacts on the water resource through the use of regulatory measures such as registration, permits, directives and prosecution, and economic incentives such as levies and fees, in order to ensure that the Resource Quality Objectives are met;
• managing demands on water resources in order to keep utilisation within the limits required for protection;
• monitoring the status of the country's water resources on a continual basis, in order to ensure that the Resource Quality Objectives are being met, and to enable us to modify programmes for resource management and impact control as and when necessary.

The Resource Quality Objectives for a water resource are a numerical or descriptive statement of the conditions which should be met in the receiving water resource, in terms of resource quality, in order to ensure that the water resource is protected.

Because they are a statement of water resource quality, and not just water quality, the Objectives have four critical components, to cover each of the aspects of ecological integrity which are necessary for protection of the Resource Base:

• requirements for water quantity, stated as Instream Flow Requirements for a river reach or estuary, or water level requirements for standing water or groundwater. These are determined according to current procedures for assessing Instream Flow Requirements (IFR);
• requirements for water quality, which are determined on the basis of current guidelines and procedures as set out in the South African Water Quality Guidelines;
• requirements for habitat integrity, which encompass the physical structure of instream and riparian habitats, as well as the vegetation aspects;
• objectives for biotic integrity, which reflect the health, community structure and distribution of aquatic biota.

Resource Quality Objectives for a water resource are set on the basis of acceptable risk: that is, the less risk we are prepared to accept of damaging the Resource Base and possibly losing the services provided by the water resource, the more stringent would be the objectives. A higher risk to the Resource Base might be accepted, in return for greater short term utilisation, and then the Resource Quality Objectives would be set at less stringent levels.

Resource Quality Objectives are scientifically derived criteria, based on the best available scientific knowledge and understanding. They represent our best assessment of the resource quality which is necessary to provide a desired level of protection to a water resource, with a particular degree of assurance or risk. Resource Quality Objectives would be derived for individual water resources, such as river reaches, sub-catchments, estuaries, coastal marine waters, wetlands or groundwater resources, on the basis of formally accepted Department of Water and Sanitation policy statements, methodologies or publications.

For aquatic ecosystems, objectives can be derived which are based on measurement and understanding of the behaviour of ecosystems in field and laboratory conditions, and especially understanding of their behaviour under stress, induced by changes in water quantity, water quality or habitat integrity.

For recognised water users, the primary focus of objectives would be on water quality aspects. Objectives for water quality for recognised water users are based on scientific understanding of the direct physiological effects of changing water quality (such as effects on human health, or damage to a sensitive crop, or toxicity to livestock), or on assessment of economic impacts (such as the cost of increased water treatment, or the loss of productivity).

Once Resource Quality Objectives have been set for a resource, then those objectives would serve as a basis for water resource management. Objectives have a number of purposes in the context of resource management:

• Objectives represent a definite goal for the desired protection level and resource quality status of a water resource, towards which management can be directed. The goal might have to be approached in steps, as part of a long term programme, and then interim objectives can be used to define the steps and the time frame for achievement.
• Objectives provide a clearly understood line between which activities and impacts are acceptable and which are not acceptable. This includes the impacts of point sources, non-point sources, incident sources, land use and development, and water abstraction;
• Objectives provide a quantifiable, verifiable baseline for measuring the success of resource management activities and for reviewing the effectiveness of source-directed control and regulatory activities;
• Objectives give a stable framework, which can be kept in place for an agreed time period, for both resource managers and the regulated community to undertake decision making and planning.

The need for caution, and the desire to prevent unintentional exceedance of the limits of sustainable utilisation, are recognised as cornerstones of the policy of protection. The approach which has been adopted is that of setting limits on the basis of acceptable risk. Hence the resource protection policy requires that quantifiable Resource Quality Objectives be set which reflect our understanding and acceptance of a particular level of risk of exceeding and possibly causing irreversible damage to a water resource.

The extent of the risk which we will accept is related to the value or importance which we place on a specific water resource. Some resources will have a very high value to us, whether because of their ecological importance and value, or because of their sensitivity to certain forms of utilisation, or because of a need to maintain long term reliability of the services provided. In such a case, we would set especially stringent Resource Quality Objectives, to minimise the risk of irreversible damage.

For other water resources, our short term needs for water or economic development might be so important or so urgent, that we would accept a greater risk of exceeding the "point of no return", and hence a greater risk of failure of the resource, in exchange for allowing more utilisation. However, the particular level of risk should be accepted by all stakeholders, including impacters and water users, with a clear and common understanding of the possible long term consequences.

Adopting a risk-based approach provides a nationally consistent basis for deciding on the acceptability of impacts, while at the same time allowing natural site-specific differences to be taken into account. It is the concepts of levels of risk, and levels of protection, which are nationally applicable, rather than the numerical objectives themselves. In only a few cases (such as for persistent toxic substances) would it be practical to set numerical objectives which would be applicable to all water resources of a particular class wherever they were in the country. A concentration which posed only a slight risk to a particular ecosystem in one geographical region may result in a much higher risk in another geographical region, depending on the resilience of the adapted ecosystem, the background quality of the water, and the natural flow regime.

In the Water Law Principles, the Reserve is specifically identified as that water quantity and quality necessary to protect basic human needs, and aquatic ecosystems. The Resource Quality Objectives for a water resource are a rigorous numeric or descriptive statement of the requirements of the Reserve for that particular water resource, in measurable, enforceable terms.

It is especially important to note that the Reserve is not just the minimum water quantity, water quality, habitat and biotic integrity required for protection. For a water resource which is classified as being of high protection status, the Reserve would be set at a higher level, which would correspond to the idea of minimum risk and maximum caution. For a water resource in a lower protection class, the Reserve would be set at a level which should still afford protection to the resource, but without the benefit of the buffer which caution provides.

Yet to assume that a "higher" Reserve necessarily means that only a greater quantity of water is allocated to protection of the resource is somewhat simplistic. The assurance or reliability of water, especially under extreme climatic conditions, is just as critical an aspect of the Reserve as the quantity and quality.

Depending on the level of risk which is acceptable, Resource Quality Objectives could be set at any level on a continuum between no protection at all (certain damage) and maximum protection (no risk). In practice, the decision on the level of protection which is desirable, the subsequent setting of objectives to reflect that decision, and the control and regulation of activities impacting on a water resource, can be streamlined and facilitated by the implementation of a protection-based classification system.

Under a national protection-based classification system, water resources can be grouped into classes representing different levels of protection. The risk which can be accepted in each class is related to the level of protection required for that class. This provides a nationally consistent basis and context for deciding on an acceptable level of short term risk, against the requirements for long term protection of a water resource. For water resources which are especially important, sensitive, or of high value, little or no risk would be acceptable, and they would be assigned a high protection class. In other cases, the need for short to medium term utilisation of a water resource may be more pressing: the resource would still be protected, but would be assigned a class which reflected a higher risk. In addition, certain activities or impacts would be regulated or controlled to a certain degree in each class. Some impacts might be prohibited entirely in the highest protection class.

A system comprising a few protection classes is recommended: the highest class, requiring the greatest level of protection, and allowing no risk to the Resource Base, would include "special" water resources of very high value. These might be special in terms of their conservation importance, or because they support very important and sensitive uses. (In some countries, the term "heritage rivers" is used to denote the highest class.) The lower classes would reflect slight risk, moderate risk or high risk of damage to the Resource Base, and the Resource Quality Objectives in each case would reflect the level of risk associated with the class.

Overall, the assignment of a specific class to a water resource gives a clear message to both users and impacters regarding the social, economic and ecological value of that water resource. Classification represents a vision of how people feel their water resource should be managed, in terms of resource quality.

Classification of a water resource, and the subsequent derivation and setting of objectives, should ideally be undertaken in a formal process of negotiation and consensus-seeking among all stakeholders. Stakeholder groups which should be represented in this process include water user sectors, industrial sectors, agricultural sectors, public sectors, special interest groups, local and regional government, as well as other government departments responsible for resource development and for resource protection.

Through such a process, all stakeholders, including water users, impacters and the regulatory agency, can come to agreement on the level of protection which will be given to the resource, in full understanding of the implications for the degree of utilisation which can be sustained, and for the kinds of impacts which are acceptable.

Ideally, the process of classification and setting of objectives should be conducted within an integrated catchment management framework, and could be co-ordinated through the relevant catchment authority or management body. The representation of local interests in this process is very important; however, since water is managed as a national resource, there should also be representation of regional and national interests, perhaps through the formal participation of regional and national government and regulatory agencies.

The purpose of a classification system is to provide a set of nationally consistent rules to guide decision making about water resources - what we will allow to happen in our water resources, and what we will not. A national classification system allows transparency, accountability and long term goal-setting to be incorporated into water resources management. Water resources which need to be improved can be identified, and the necessary control measures can be implemented to meet the requirements associated with the assigned class.

A classification system need not be highly complex. In some countries, the terms "drinkable", "swimmable" and "fishable" are used to classify water resources: the water quality requirements would be most stringent for the "drinkable" class, and focused on microbiological contaminants in water. Immediately a class such as "drinkable", "swimmable" or "fishable" is assigned to a water resource, it is possible to set rules about what may be allowed to be discharged to the resource and what conditions must be maintained in the resource.

Table 1 shows an example of how classification of a water resource might be used to set water environment objectives which reflect an agreed balance between protection and utilisation. The new policy requires that the classification system should encompass resource quality, not just water quality, and so objectives for ecological aspects must be incorporated into classification, in the manner proposed in Table 1. The characteristics of the ecological integrity protection classes A through D are described in Table 3, and resource quality objectives can be derived in order to protect and maintain those characteristics. In a similar manner, the fitness for use classes shown in Table 2 can be used as a basis for deriving numerical objectives to maintain certain water quality characteristics.

The objectives for utilisation (water quantity, water quality and land use) would of necessity be set within the constraints of what would be suitable for the aquatic ecosystem: for example, a largely unmodified river could be assigned a class B status, but natural background conditions may be such that the water in the river would not meet, say, Class I irrigation objectives due to naturally high TDS. Nevertheless, the objectives for maintenance of ecological integrity at class B status would determine or constrain the activities which would be permitted and the human uses for which that river might be fit.

Thus River X, reach 2 would have a classification of Bd_IIa_IIIr_i. This means that

r_i: the water resource would be fit for intermediate contact recreation.

Once these characteristics, related to the desired status of a water resource, have been decided, then numerical and narrative water environment objectives can be set for the reach in question, for flow, water quality, habitat integrity and biotic integrity, such that the desired ecological and fitness-for-use status can be achieved and maintained.

6. PROPOSED CLASSIFICATION SYSTEM FOR WATER RESOURCES

The final, full classification system for water resources in South Africa will integrate the rules for ecosystem protection (4 classes A to D), the rules for protection of basic human needs (5 classes blue to purple, assuming basic treatment) and water users (recreation, agriculture, industry, bulk domestic supply). Three integrated management classes are proposed, as follows:

Class I: Special Water Resources

• Retain natural or almost natural ecological characteristics (ecological class A)
• Safe for contact recreation and most water uses, including sensitive uses
• Can be used for basic human needs with minimum treatment

Class II: General Water Resources

• Retain a high degree of ecological function and integrity (ecological class B to high C)
• Safe for some recreation and non-sensitive water uses
• Can be used for basic human needs with conventional treatment

Class III: "Hard-working" Water Resources

• Retain at least some ecological function, but probably highly modified from natural (ecological class D)
• Safe for some non-contact recreation and some non-sensitive water uses
• May require advanced treatment to meet basic human needs requirements