WATER QUALITY AND AGRICULTURAL WATER USE IN SOUTH AFRICA:
RESEARCH AND TECHNOLOGY TRANSFER ARC: PUBLIC SUPPORT SERVICES DIVISION
INTRODUCTION
One
of the pillars of the ARC-PSS Division is to promote the sustainable management
and use of the agricultural natural resources through research, technology
development, technology transfer and scientific services. The ultimate
objective of the research and development (R&D) is to increase the
productive efficiency of agro-ecosystems. One of the key strategic focus areas
of research and information generation is on 'Water quality and agricultural
water use"
CURRENT RESEARCH/ACTIVITIES RELATED TO WATER QUALITY
The following are some of the main research focus areas and activities
being carried out within the ARC-PSS division:
1. Assessment of the effect of different water qualities on crop production.
The study focuses on the constraints and types of crop that can be grown in a
study area (near Blesbokspruit) as part of the Grootvlei Desalinisation
Project. '
2. The effect of Wetland systems and Goldmine effluent water use on irrigated
agriculture. The project evaluates the Blesbokspruit wetlands with respect to
pollution from industrial, mining and sewerage discharges.
3. Water quality analysis for agricultural use in rural areas of the Eastern
Cape. KwaZulu Natal and the Western Cape provinces. The Analytical laboratory
at the Institute for Soil, Climate and Water (ISCW) analysed over 250 samples
for water quality during 2005 for the DoA (Water Use and Irrigation Development
Directorate). The water is from boreholes used for both domestic and
agricultural production. During 2006/07, 300 samples are likely to be analysed
for Mpumalanga and Gauteng provinces.
4. Assessment of Water Quality and land degradation in Wetland areas. The
Institute for Soil, Climate and Water has established a working group which
will focus on "Conservation of Wetlands". During 2005, iln the
Eastern Cape Province, an awareness project was conducted at Umthatha catchment
Dam. Three more proposals have been submitted for 2006/07 for Gauteng, and the
Eastern Cape Provinces to rehabilitate wetlands and assess water quality in
these wetland lands.
5. Impact of water quality in Irrigation schemes. This is an on-going project
which deals with assessing water quality in irrigation schemes under the RESIS
programme in the Limpopo Province
6. Soil-Crop-Water quality studies ie. Monitoring the effect of water quality
and soil and land productivity. Under this project, the emphasis is to evaluate
the water quality degradation in our river systems and its impact on soil
erosion, crop and grazing land
7. Water quality analysis for SA DC countries: As part of our international and
SADC obligations, ISCW analytical laboratory is involved in various projects in
water quality analysis as follows:
·
Zambia (26 samples received from Dept of Water affairs);
·
Lesotho (samples from Lesotho Highlands project);
·
Botswana (samples received from mining company)
8. Rain water harvesting project. Since water is a scarce resource, ISCW
embarked on developing methods and technologies to improve the retention of
rain water based on In-field water harvesting technologies. New projects have
been initiated to look into other rain water harvesting technologies such as
water from roofs and roads which can be used for agricultural purposes.
9. Conservation agriculture including land care projects. Technologies which
conserve soil and water have been developed and transferred to various farmers
in KwaZulu Natal, Limpopo and the Eastern Cape province.
During 2005/06, the ISCW received recognition in water related projects by
receiving the following awards: The KwaMhlanga LandCare project, for which ISCW
is the main service provider, was awarded a trophy for the best overall
LandCare project in Mpumalanga, as the project implementing most LandCare
principles; the water harvesting group based in the Free State Province was one
of the five National Science and Technology Forum Award finalists in the
category for organizations that have made an outstanding contribution towards
science, engineering and technology over the last 10 years
CHALLENGES AND FUTURE ACTIVITIES
Soil salinity is a major problem that affects virtually all of the major
irrigation schemes in South Africa. With the increased use of the water
resources, the salinity level in the rivers is bound to rise in future and this
is likely to exacerbate the extent of the problem. Through return flow to river
systems, irrigation itself may contribute to this hazard.
Two flagship awareness campaigns of national agricultural and environmental
importance in which the ARC-PSS division actively participated, are climate
change and the conservation of wetlands. Climate change is one of the currently
key scientific and policy issues of great concern as perturbations in climate
parameters could be largely amplified by adding to the already high risk and
stressed water resources and to socio-economic well-being. In addition to its
natural resource conservation, ISCW has initiated activities to improve
wetlands and water quality management
Wetlands can be regarded as the biological congregation where water and land
overlap. Wetlands act as natural water harvesting points and therefore
constitute a valuable agricultural resource with significant benefits in terms
of food security, health and income. The unsustainable management and
utilization of wetlands, however, is bound to contribute to the loss in natural
capital with harmful consequences for peoples' livelihoods. Best practices must
therefore be identified and developed so that wetland management can be
tailored to landscape conditions and potential. One of the major constraints to
the sustainable use and management of wetlands is insufficient knowledge or the
lack of knowledge.
Gold mining activities in the Witwatersrand area have created certain concerns
about the radio active pollution of the river systems in that area since the
early 90s. The possible presence of Uranium in the river systems of the said
area, amongst others, is presumed to be from sediments of the mining activities
or through decanting of ground water (Dolomite aquifer).
Screening surveys of radioactivity in the Mooi River catchment were conducted
by the Institute of Water Quality Studies (IWQS) of the Department of Water Affairs
and Forestry in 1995 and 1996. Elevated levels of radionuclide of uranium and
radium were detected in streams close to mining activities.
In terms of the results of this study, it was found that although the great
majority of sampling sites in the catchments showed low levels of water born
radionuclide, the sites that showed significant concentrations of water born
radionuclide were associated with discharges of mine water into the river
system, while the levels of radioactivity in the water column declined with
distance from the mining operations.
In view of the fact that there are irrigation areas downstream of Mooi river
and many other rivers in the Witwatersrand areas, associated with gold mining
activities, the more detailed investigations as stipulated above, should cover
the impact of such risks to humans through consumption of agricultural products
from these schemes.
The following could form part of a nationwide research agenda in order to find
solutions due to increasing water demand and increasing water quality
degradation:
·
Research in water quality degradation to establish the extent of
degradation in our river systems, wetlands and irrigation schemes.
·
Soil-crop-water quality studies with emphasis on developing monitoring
tools/technologies and assessing impacts of soil erosion, mining and water from
industries
·
Development of water quality monitoring tools and guidelines due to
return flow from irrigation, mining and industries
·
Establishment of a comprehensive country wide water quality monitoring
network