International Journal of Environmental Sciences Kgabi & Joseph Vol. 1 No.4 ISSN: 2277-1948 Online version available at: www.crdeep.com International Journal of Environmental Sciences Vol. 1 No. 4. 2012. Pp. 299-305 © Copyright by CRDEEP. All Rights Reserved. Full Length Research Paper D etermination of the Q uality of W ater in the Gammams River, W indhoek N nenesi Kgabi * & Gabriel Joseph Department of Environmental H ealth Sciences, Polytechnic of Namibia, Private Bag 13388, W indhoek, 9000 * Corresponding Author: N nenesi Kgabi ABSTRACT In this study chemical (COD, BOD, Copper & nitrate), biological (total coliforms, faecal coliforms and E-coli) and physical (turbidity, T DS, DO & pH ) water quality parameters were analysed for three study sites within the W indhoek City; and households in the vicinity of the Gammams river were surveyed using a standardized questionnaire. T he overall quality of the Gammams River can be represented per sampling point from poor to good as: W indhoek W est, Khomasdal, and Dorado Park. The W indhoek W est site contained the highest number of damaged manholes, signs of improper w aste disposal, high turbidity, BOD, COD, coliforms, high nitrates and copper; while Dorado Park had clear water, no manholes, no waste, and all the other characteristics of a healthy/good quality river. The quality of Gammams River differs from point to point within the same stream. This indicates the possible risk depending on the topography, run-off and meteorology of the area. All the parameters measured during this study exceeded the set standards and guidelines. T he results indicated high turbidity (9.99 NT U) upstream; faecal coliforms between 10 and innumerable counts/100 ml, and total coliforms (170 to innumerable); nitrate concentrations (1.5 to 28 mg/l) and dissolved oxygen ranging between 0.44mg/l and 11.41mg/l. The high coliform counts and other water quality parameters values exceeding acceptable limits are indicative of pollution from domestic wastes, open defecating, as well as from municipal sewer systems. Key words: W ater quality, Gammams River, water quality parameters INTRODUCTION Eighty percent of the rivers in Sub-Saharan Africa are trans- boundary (Duda & El-Ashry, 2000). These rivers have a high resource potential for socio-economic development through fisheries, tourism and recreation, irrigation schemes and hydropower generation. They also facilitate inter-country cooperation, meeting the goals and objectives of the African Union (UNECA, 2000). As a continent, Africa’s proportion of freshwater resource is comparable to its portion of the global population. Quality of water in rivers is a combination of their ionic composition, mineralization, the dissolved organic matter content, and the total and permanent hardness. The composition and characteristics of water in streams and rivers is determinative to a certain degree for its utilisation as a resource for variable economic activities; it is also crucial for the structure and function condition of aquatic ecosystems and the hydro-ecological safety of the river basins. The quality of a river at any point reflects several major influences including atmospheric inputs, climatic conditions and anthropogenic inputs (Bricker & Jones, 1995). The Gammams River is a non-perennial river that starts in the undeveloped parts of Olympia near Auasblick. The river passes through some of the up-market residential areas of Windhoek and the stream is very polluted (Pedro, 2009). Windhoek, the capital city of Namibia, is located in the Central Highlands approximately 1,540m above mean sea level. The annual rainfall in Windhoek is approximately 370 mm, while the potential surface evaporation rate is in the range of 3,200–3,400 mm/annum (Department of Water Affairs, 1988). Windhoek obtains its water from the four main sources of water namely: Von Bach Dam, groundwater (50 municipal production boreholes), and reclaimed water from both the New Goreangab Water Reclamation Plant (NGWRP) and the Old Goreangab Water Reclamation Plant (OGWRP) (Lahnsteiner & Lempert, 2005). The water demand for the city is constantly increasing due to the rapid industrial developments and population growth. The pollution of surface water from urban streams may have the potential to pollute the underground water resources (Pedro, 2009). Common water contaminants include suspended soil particles from erosion that cause turbidity and sediments in water bodies; inputs of nutrients that promote eutrophication, high primary productivity and depletion of dissolved oxygen; toxic substances such as heavy metals, pesticides and industrial chemicals and heated water from cooling of industrial processes. There are also additional possible effects on the water body which include; rise in organic load, metals and salt content, microbiological load, algal blooms, pharmaceutical products and endocrine disruptors (Iiputa et al., 2008). These may result in the following problems during treatment; taste and odour, filter clogging by algae, algae toxins, difficulties in treating the water, higher treatment cost, higher chlorine demand, bacterial and other growth in the pipes and distribution system, higher potential for pathogenic microbial pollution of the distribution system, metal deposits in reservoirs and distribution system, enhancement of corrosion, 299