At a basin or sub-basin scale, particularly in semi-arid and arid areas, priority is often placed on monitoring and management of water quantity. Equally important, however, is the monitoring and management of water quality (DWAF 2004).
Quality is often characterised in terms of the concentration of different chemicals in the water (Hatfield 2008). What determines “good” or “bad” water quality depends on the purpose of the assessment and the intended use of the water — for example, water with naturally high concentrations of some metals may be unsafe to drink, but still suitable for agricultural purposes.
Water quality assessment involves comparing measured chemical concentrations with natural, background, or baseline concentrations, and with guidelines established to protect human health or the environment.
This chapter describes how physical, chemical, biological and qualitative indicators are used to come to the conclusions below and what human activities are most likely to contribute to the water quality problems in the basin. Below is a summary of key issues for water quality in the Kunene River basin.
Kunene River near Epupa.
Source: Langenhove 2007
( click to enlarge )
Key Facts
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The Kunene River is relatively unpolluted and the water quality is considered to be good as the basin contains only limited irrigated agriculture and industry. However, no significant, concluaive water quality assessment has been carried out in the basin;
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There are concerns where the river passes through settlements in the catchment of the possibility of micro-biological pollution from untreated and partially treated sewage outflows;
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The enormous potential for mining and industrial development raises the concern for future water quality issues;
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Deforestation, uncontrolled burning and the application of non-conservational agricultural techniques are leading to a decrease of surface water quality through soil erosion; and
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The storage of water through huge dams along the Kunene River has a negative downstream impact on water quality, resulting for example in a change of dissolved oxygen and nutrient concentration.
Chapter Summary
This chapter covers the following concepts and material:
Detailed information about the importance of water quality monitoring can be found under Resource Monitoring.
