Volume II - The Northern Cape Provincial Spatial Development ...

Northern Cape PSDF
Volume 2
December 2011
low flows and the lack of variation in flow has been identified as contributing factors to the
eutrophic conditions in the middle reaches of the Vaal River.
Water quality studies have also found localised occurrence of microbiological pollutants in
specific catchments, including the Harts River catchment. The reason for microbiological
contamination is that many of the wastewater treatment works are not performing to their
specifications and are not complying with their licence discharge standard requirements.
Investigations have found that the maintenance and management of the sewerage systems
have also fallen into disrepair in many of the local municipalities in the immediate vicinity of
the specific catchment. This is resulting in microbiological pollution of the receiving streams
with the resulting public health issues.
C.2.8.2 LOWER ORANGE
Nutrients and algae blooms are the main concern in the Lower Orange WMA. Salination is
currently not the main problem experienced in the Lower Orange WMA in terms of water
quality. The pre‐feasibility study conducted in 2004/2005 found that total dissolved salts
concentrations in the Orange River, just downstream of its confluence with the Vaal River,
were in a range of 150 to 160 mg/l. However, according to the September/October 2006
edition of ‘The Water Wheel’, substantial volumes of low salinity water from the Orange
River has been diverted to the Vaal River Catchment since the implementation of the
Lesotho Highlands Water Project. This has led to increased salt levels in the Gariep and
Vanderkloof dams. The article reports on a Water Research Council funded study focused on
the river reach between Boegoeberg and Onseepkans. More than 35 000 ha of land in this
area are under irrigation cultivation, with 60% grapes and 20% cotton. The study found that
the water in this stretch is still in relatively good quality, with limited potential for salinity
and sodicity, but that there are problems in the area between Onseepkans to Alexander Bay,
with the highest potential for problems at Alexander Bay where the water quality was
influenced by tidal flows. However, an unyielding increase in salinity could seriously affect
the economy of the Boegoeberg‐Onseepkans area, as it has been found that grapevines are
more sensitive to salinity under local conditions than found by international salinity
guidelines. The following water quality management strategies for the Vaal River have been
recommended 4 :
a) Improving management of the water resources of the system by more effective
monitoring, assessment and reporting.
b) Implementing source control measures through licensing, EIA and EMPR processes.
c) Putting in place Water Quality Objectives (WQOs).
d) Maintaining or improving the water quality of the water resources of the system for
all users and beneficial uses
e) Controlling the salinity, eutrophication and microbiological levels.
C.2.9 WATER‐RELATED KEY ISSUES
4
As recommended in the following documents:
DWAF. 2004. Internal strategic perspective – System: Overarching. February 2004. Report number P RSA
D000/00/0104. Page 2‐16.
DWAF. 2008. Integrated water quality management plan for the Vaal River system: Water Quality
Management Strategy. Directorate National Water Resource Planning. Report
Office of the Premier &
Department of Rural Development & Land Reform
26
Dennis Moss Partnership