The Namibian Scoring System (NASS) version 2 rapid bio-assessment method for rivers

  • R W Palmer Palmer Environmental Consultants, PO Box 4349, White River 1240, South Africa
  • E D Taylor IUCN — The World Conservation Union, Okavango Delta Management Plan, PO Box 35, Maun, Botswana
Keywords: aquatic invertebrates, biomonitoring, biotic index, Caprivi, Namibia, river health, SASS5, Zambezi


This paper presents a rapid bio-assessment method for assessing the ecological condition of streams and rivers in Namibia. The method uses the composition and abundance of aquatic invertebrates, which are identified in the field, mostly to family level. The method is based on the South African Scoring System version 5 (SASS5), which has been modified to account for additional tropical invertebrate taxa that occur in northern Namibia. The method was applied to the Zambezi River near Katima Mulilo and NASS results were found to fluctuate predictably with changes in water level. Training of Namibian personnel to apply the method, as part of the National Water Quality Monitoring Programme, is recommended.

African Journal of Aquatic Science 2004, 29(2): 229–234

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eISSN: 1727-9364
print ISSN: 1608-5914