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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:
- 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.
- 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.
- 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.
- 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.
- 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.
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