Transcript Water Quality Presentation

State of water quality in South Africa
Masibambane Coordinating Committee Meeting
Birchwood Hotel
25 February 2010
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Outline
• Background
– Contributing factors to water quality problems
– Impacts of factors on water
• Status of water quality & effects on human
health
• Status of dam storage
• Conclusion
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Background
• To establish the status and trends of water quality,
monitoring and assessments are critical to collect
data.
• Good design of monitoring programmes ensures data
that add value in managing water resources and
decision making.
• Good management of water is about partnership
with relevant stakeholders (interested parties) (Good
Governance).
• River flows play an important role in the regulation
of the quality of water.
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Contributing factors to water quality
problems
• Return flows from irrigation that may contain high
salt loads.
• Sewage treatment plants discharging poor quality
effluent including raw sewage.
• Mining & industrial activities.
• Afforestation and erosion due to poor land-use
practices.
• Informal settlements
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Impacts of these factors on water
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Salinisation (from salts)
Feacal pollution
Eutrophication
Sedimentation
Toxicity (POPs e.g. DDT used for Rx of malaria )
Radioactivity (uranium, strotium)
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Status and effects on human health
• Salinisation is a major problem
– The southern eastern and western cape have potential high risk to human
health because of high levels of salts. Chloride & Sodium are the major
contributors (1st picture).
• Faecal contamination poses a high risk (ito water-born diseases) in most
areas if drank without treatment (2ndpicture).
• Eutrophication
– High levels of nutrients () render water unfit for use
– may block the aquatic organisms airways.
• Most WMAs experience significant to severe problems related to
eutrophication.
– The most affected impoundments, Hartbeespoort, Rietvlei and
Roodeplaat dams, are in the Crocodile West-Marico WMA.
– The Middle Vaal WMA has serious eutrophication potential
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Storage water in reservoirs
• Water storage varies in the country with the
southern cape experiencing very low levels and parts
of eastern cape having moderately low levels.
• Others part of the country have moderate to high
storage.
• However, looking at individual catchments, some are
experiencing low flow which result in water
restrictions being imposed.
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Conclusion
• Monitoring & assessments are critical to
protect water resources
– This translates to prevention or limiting pollution.
– Prevention of pollution will ensure water is fit for
use or water quality is good.
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