An integrated assessment of socio-economic and ... - Unesco

Operational information Celiwe Mbuli
The Orange River is the longest river in Southern Africa, stretching from Lesotho
down to the Orange River mouth in Alexandra Bay. One of the main tributaries of the
Orange is the Vaal River. Analysis from the Water Resources Yield Model shows that
1680Mm 3 /a of water still enters the Orange from the Vaal; although the Vaal River
System is operated such that the outflows from the Vaal River System into the
Orange River are minimised. These inflows occur as a result of uncontrolled spills
from major dams upstream of the Orange/Vaal confluence, local runoff generated in
the intervening catchment downstream of the major dams and upstream of the
Orange-Vaal confluence as well as a result of operational losses in the Lower Vaal.
Many transfers occur from the Orange River catchment as well as to and from the
Vaal River catchment. The developments that are taking place in the Upper Vaal
affect the water quality downstream in the form of return irrigation flows and
discharge. Interdependency within the system therefore makes operation
complicated and increases the need to operate the Vaal and the Orange River in an
integrated systems context.
Water quality in the Lower Vaal catchment is poor; for example in the Harts River
before its confluence with the Vaal River. Taung dam on the upper reaches of the
Harts River is currently unused. Options to utilize this dam need to be analysed to
determine the long term yield of the dam and possibly operating rules could then be
determined to efficiently use the dam.
The National Water Act (36 of 1998) requires that water for the Reserve should be
allocated before any other developments. Water management plans that will give
effect to operationalisation of the reserve need to be developed. For example if from
the analysis of determining the options for Phase 2 of Lesotho Highlands Water
Project, it is determined that there is surplus water available in Katse Dam, water
could then be released from the Dam to improve the situation in the Orange River.
As part of Water Conservation and Water Demand Management, reduction of
operational losses needs to be seriously looked at; for example Water Management
Plans that prioritize irrigation schemes to install metering systems need to be
developed. This will create consumer awareness for effective water use. Rainwater
harvesting as recommended in the Orange River Replanning Study will contribute to
more effective irrigation schemes, it will also improve socio-economic status of
dependent marginalized communities.
Regular liaison among water managers in setting objectives for managing the
Orange River basin is necessary. Collaboration needs to be improved to discuss
issues of common interest.
To conclude; the complexity of operation of the system in an integrated manner
remains a challenge. Implementation of all the policies in place is an iterative process
which will have to be tested and periodically updated through involvement of all roleplayers
including environmental scientists and socio-economists. If something
doesn’t work out we will have to revisit the strategies and try different ones.
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