Assessment of water quality for river health using macroinvertebrates and selected physicochemical parameters: a case study of the Orange River in Namibia
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Date
2013
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Publisher
University of Dar es Salaam
Abstract
The land use activities which have an effect on water quality and river health are believed to be increasing along the Orange River in Namibia. These are irrigation with more than 2000 ha under irrigation and approximately 2000 ha planned for the future, urban development at Noordoewer and Aussenkehr; and weir construction at Sendelingsdrift. Population increase has resulted in informal settlement proliferation, with no proper sanitation facilities at Aussenkehr. This study aimed at assessing the current water quality and overall health of the Orange River in Namibia. Eight sites were sampled for macroinvertebrates, physical and chemical water quality parameters such as: nutrients in the water, its pH, turbidity, presence of bacteria, etc. Landsat images were also used to assess the influence of land-uses on water quality. Existing institutional and legal frameworks on river health in Namibia were also reviewed. South African Scoring System (SASS) results indicated a fair water quality condition in category C showing that the river is moderately modified. Water quality parameters at all sites varied moderately and were within acceptable limits, except for turbidity and chlorophyll a. There was a significant difference in the mean concentrations of all nine water quality parameters among sampling periods, whereby F-value > F-critical at α = 0.05 among sites, F-value < F-critical at α = 0.05, except for turbidity and chlorophyll a. The Landsat images also showed minimal changes in land-use activities between 2002 and 2012, with difference of about 38 ha in irrigated area. It was also found that policies and legislations address water resources management from a broader spectrum, not specific to river health. It was concluded that the water in the Orange River is still fit for use. However, there is an urgency to develop a water quality monitoring and river health programme.
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Keywords
Water quality management, Orange River, Macroinvertebrates, Namibia
Citation
Munyika, S. N (2013) Assessment of water quality for river health using macroinvertebrates and selected physicochemical parameters: a case study of the Orange River in Namibia, Master dissertation, University of Dar es Salaam. (Available at http://41.86.178.3/internetserver3.1.2/detail.aspx)