AWARE

Agent-based Watershed Analyses for Resource and Economic Sustainability

S. Farolfi (coordinator) - S. Perret - L. Erasmus - P. Bommel

The National Water Act of South Africa promotes integrated and decentralised water resource management as well as the set-up of new institutions. The main objective of the National Water Resource Strategy (NWRS) is to match and balance water demand with water supply, according to sustainability, equity and efficiency objectives.

The implementation of the Act and its' related NWRS face many social questions and economic uncertainties, owing to a context of water scarcity, profusion of users and uses, backlogs and inequalities in infrastructure and water supply. In this context it is believed that one of the key tasks that is incumbent upon Catchment Management Agencies and Committees (CMAs - CMCs) is to regulate and control water demand.

The approach set up for this purpose is the allocation of water use authorisations to users for which a licensing process is necessary. This a process raises a number of questions as to how to prioritise licensing between different use and users, when and how should the licenses be revised and what might be the impact of certain licensing strategies.

AWARE is a multi-agent systems model constructed in Cormas © to investigate the economic efficiency, environmental sustainability and social desirability of some of the potential water management strategies that Catchment Management Committees could use. Although actual processes are unfolding and developing progressively, AWARE aims at investigating situations whereby once established, CMAs and CMCs would handle the licensing processes. It is a prospective simulation-oriented tool.

The perspectives and behaviour of the Catchment Management Agency (CMA) and the individual users are represented in AWARE. These individual users include communities, irrigation boards, forestry agencies, industries and mines.

The Steelpoort sub basin in the Olifants river catchments has been selected as study area because of its complete representation of the major sectors of water use and the availability of data. Attributes of the Steelpoort sub basin such as elevation means annual run-off. Land use has been obtained from a geographic information system (GIS). The average annual run-off is used to calculate the total volume of water that is available to the CMA, and includes water available for licensing for human utilisation and water available for the preservation of essential ecosystems (ecological reserve).

Water quotas are allocated and issued by the CMA every 5 years. When licenses are to be issued, water users (urban and rural communities, irrigation boards, livestock farmers, forestry agencies, industries and mines) send an estimate of water demand to the CMA. If the demand for water for which the CMA will issue licenses is higher than the water demanded by all the users, each user will receive a quota or license for the amount of water it has requested. If the water demanded is more than the volume to be licensed, the CMA prioritises the issuing of licenses according to one of five strategies below:

1. No prioritisation. All users receive licenses for a percentage of the amount of water that they have requested. This percentage is the same for all users and depends on the overall available resource. The ecological reserve is not used in licensing.
2. Social strategy. Urban and rural communities are issued with licenses first. The rest of the users share remaining unlicensed water proportionately so that all users receive licenses for an equivalent percentage of what they have requested. The ecological reserve is not used in licensing.
3. Rural strategy. Smallholders as well as irrigation boards are prioritised after the rural communities have received licences. After these three user categories, remaining unlicensed water is shared between the remaining users. All such users receive licenses for equivalent percentages of what they had demanded. The ecological reserve is not used in licensing.
4. Ecological-economic strategy. Mines and industries are prioritised for water licensing. Thereafter the rest of the users share remaining unlicensed water. All such users receive a license for an equivalent percentage of the water they have demanded. The ecological reserve is not used in licensing.
5. Economic strategy. Again mines and industries are prioritised for water licensing. Water licenses are allocated to the rest of the users as such that all users receive a license for an equivalent percentage of the water they have demanded. If the water licensed to these users is less than what they have requested, the ecological reserve will also be licensed by the CMA.
   

Each type of user is charged a sector-dependent price per unit of water for which they receive quotas. These quotas are used to calculate the annual income for the CMA. The CMA's income is therefore independent of the actual amount of water received by the users. In order to calculate the actual annual volume of water received by the users, a periodic fluctuation around the mean annual runoff, representative of the South African climate, was used. If the annual run-off is more than or equal to the amount of water licensed by the CMA, each user receives the same volume of water as per received license. If the annual run-off is less than the volume of water licensed by the CMA, each user receives a proportionate percentage of the water it has been granted a license for. This proportion is equivalent to the percent of water licensed by the CMA that is available in runoff in that particular year.

Each user makes an annual assessment of the amount of water it receives. If the water quota is less than satisfactory, a complaint of water shortage is sent to the CMA. A users level of satisfaction depends on its sector of water use. After five years, licenses for water use are reallocated (the basic time frame for the model is a year).

AWARE is useful for investigating the economic, environmental and social consequences of strategies that the CMAs may use in issuing licenses for water allocation. The model can be used to compare different strategies in terms of economic effectiveness, environmental sustainability and social desirability. Since AWARE is individual-based, it is useful in elucidating global outcomes resulting from individual behaviours that otherwise would only have become obvious though trial-error management.

AWARE can only be applied to situations for which the model was originally constructed. In other words the model cannot be used to investigate the effectiveness of the CMA's management strategies under economic scenarios of growth or stasis or social scenarios such as the effect of HIV/Aids on water demand since these factors have not been incorporated in the model.

For further information visit the CeePA web site (The Centre for Environmental Economics and Policy in Africa) or contact the authors.