Background
The water requirements in the Olifants Water Management Area (WMA) have increased
substantially over the last number of years due to diverse activities – power
generation, mining, steel industry, urban development, eco-tourism and
agriculture. The mining industry in particular has grown fast in this area.
The Olifants River catchment is currently one of South Africa’s most stressed
catchments as far as water quantity and water quality is concerned.
A reconciliation strategy needs to be developed for the study area to alleviate
the current water deficits and to ensure a sustainable water supply for the next
20 years.
It was decided to add the towns of Polokwane and Mokopane and surrounding areas
to the study area as Polokwane already receives water from the Olifants
catchment and Mokopane will also soon receive water from Flag Boshielo Dam in
the catchment.
Rationale of the study
Various concerns have contributed to this urgent need for the development of the
strategy:
Concern 1: Water quality problems as a result of industries, mining and
irrigation.
Mining activities in the upper parts of the Olifants Catchment cause drainage of
acidic water into the rivers. Serious acid conditions prevail in the Klipspruit
and Kromdraaispruit catchments due to failed neutralization plants. The sulphate
concentrations exceed the Resource Water Quality Objectives (RWQO) in a number
of catchments. The total dissolved solids (TDS) and sulphate concentrations in
the Witbank, Middelburg and Loskop Dams have been increasing since 1970.
Sulphate load will have to be removed from the system to arrest the increase.
The sources of pollution are not only mines but also power stations and
industries. The trophic status of the rivers and dams are mesotrophic. Four of
the five major waste water treatment plants discharge into streams which flow
directly into the upper end of the Loskop Dam. This has resulted in eutrophic
conditions in the dam with periodic blue green algae blooms.
Many of the mines are filling with water and have reached a stage where they are
generating excess water that needs to be managed. This excess mine water is in
excess of the contribution that would be made naturally by the mined catchment
area. Mine water treatment and reclamation is being pursued by a number of mines
using desalination technologies to treat mine water to potable standards. The
Emalahleni Mine Water Reclamation Plant (MWRP) is operational and the Optimum
MWRP is under construction.
Return flows from irrigation lands contain high salt loads and increase the
salinity of the receiving streams. The water entering the main stem of the
Olifants River via Flag Boshielo Dam is already salinised to such an extent that
it exceeds the Target Water Quality Range for TDS for more than 50% of the time.
Concern 2: Sewage effluent from municipalities does not meet the water quality
standards.
Waste water treatment plants in the catchment are performing poorly and are
overloaded, resulting in discharge of organics, phosphate and amonia into the
Olifants River.
Concern 3: Mining operations in the catchment – Increase in water requirements.
The growth in the mining industry has increased the water requirements in the
catchment significantly. The De Hoop Dam and pipeline infrastructure will
satisfy the water requirements for some time, but if the mining industry keeps
growing, further water augmentation schemes will be required. The mining
industry brings wealth to the area and water supply to the mines should be
supported. However, the industry can also cause a series of pollution problems,
as mentioned in Concern 1.
Concern 4: Growing water requirements – Urban and Rural.
The total population in the study area exceeds 3 million people. The added towns
to the study area, Polokwane and Mokopane have populations of 168 000 and 89 000
respectively. The majority of the people live in rural areas and the households
are situated over a wide spread area. These households are greatly dependent on
groundwater, but groundwater yields in 90% of the study area are relatively low
(between 0.1 ℓ/s – 1.0 ℓ/s). Augmenting the water supply to the rural households
is therefore a problem. Some areas will soon be serviced from the pipelines from
De Hoop and Flag Boshielo Dams, but only areas on the pipeline routes to
Polokwane and Mokopane can be reached.
The growing mining industry causes an increase in water demands in urban centres
and municipalities must cater for these population growths.
Concern 5: Further Water transfers, in and out will be required.
The Olifants River Catchment is dependent on a number of other catchments and the
Limpopo WMA has a growing dependency on the Olifants catchment.
There are several water transfer schemes in and out of the Olifants River
Catchment. These have been presented in Table 1.
Table 1: Water Transfers in and out of the Olifants Catchment (2010 estimate)
|
From/To |
In |
Out |
|
Metsweding |
|
5 million m3/a |
|
Vaal |
77 million m3/a |
|
|
Usutu |
51 million m3/a |
|
|
Komati |
100 million m3/a |
|
|
Polokwane |
|
9 million m3/a |
|
Total |
228 million m3/a |
14 million m3/a |
All the transfers into the catchment occur in the Upper Olifants, and are
mainly utilised for cooling water for power generation by the Eskom power
stations. The transfer out to Metsweding occurs from the Upper catchment,
whereas the transfer to Polokwane occurs from the Middle Olifants.
The pipeline which is planned for Mokopane from Flag Boshielo Dam will have a
capacity to convey 40 million m3/a to the town.
The water transfer to Polokwane which is currently 9 million m3/a, is also
expected to increase in the near future.
Concern 6: High water consumption by the Irrigation Sector
The irrigation sector consumes approximately 70% of all water use in the
catchment. The irrigation sector, however, is not the best contributor to the
GDP of the study area. Any further developed yield should be made available to
the environment and other higher priority water users.
It is not the intention to cut the existing water allocations to the irrigation
sector in the catchment to such extent that this will have a ripple effect in
terms of job losses and poverty.
The DWA’s objectives in terms of the Water Allocation Reform programme where
equity to access for water is promoted, also places an increasing demand on the
available water.
Concern 7: Invasive Alien Plants
Invasive Alien Plants (IAPs) such as Black Wattle have taken the space of
various indigenous plants. The alien plants use more water than indigenous
plants and reduces the surface water runoff in the rivers. It is estimated that
approximately 440 km2 of the catchment area is infested with IAPs.
Concern 8: Ecological Water Requirements
The ecological water requirement component of the Reserve was determined more
than 10 years ago. However, in order to maintain the lower stretch of the
Olifants River (the portion that runs through the Kruger National Park) in a
Category B, a water requirement of 400 million m3/a in the form of low flows and
freshets was determined. If the lower part of the river is allowed to
deteriorate to Category C, 300 million m3/a will still be required. The B
Category requirement is equivalent to a 98% assurance of supply of 200 million
m3/a.
This ecological requirement results in a current water deficit of 207 million
m3/a and, if no interventions are implemented, it will result in a future water
deficit of 263 million m3/a in 20 years’ time, because of the growth in water
requirements.
Concern 9: Meet the international obligations
A treaty between the Governments of the Republics of South Africa and Portugal
relating to Massinger Dam was signed in 1971. The Treaty was taken over by
Moçambique. The SADC Protocol on Shared Watercourses will have to be honoured by
South Africa and Moçambique.
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