A spatial analysis of eutrophication in dam reservoir water on the Molopo River at Mafikeng, South Africa

摘要: Abstract In water-scarce environments, surface water bodies serve both as sources and waste disposal channels. The Molopo River that drains through Mafikeng, South Africa, has been dammed for agricultural municipal supply, resulting in four reservoirs near Mafikeng. It receives discharges from point pollution source sewage processing plants. this study the spatial variation manifestation of eutrophication reservoir was examined. Surface samples were collected July (dry season), analysed nutrient (NO3−, PO43−) concentrations. dry season low river flow period perceived when problem is more acute. Near infrared (NIR) reflectance reservoirs, due to algae macrophytes like lettuce (Pistia stratiotes), used on satellite imagery. presence these plant NIR reflectors assessed using near-concurrent multispectral SPOT 5 images. image digital number (DN) values converted values. Geostatistical analysis indicated autocorrelation algal abundance by (NIR, 0.78–0.89 μm) reflectance. Ordinary kriging interpolation change away sources. Reservoirs with direct effluent had higher concentrations than those without results indicate range between eutrophic hypertrophic, show suitability imagery use assessment support environmental quality assessments inland bodies.