Integration of physicochemical assessment of water quality with remote sensing techniques for the Dikgathong Damin Botswana.

Water quality has become a global concern due to ever increasing population and developmental activities that are polluting water resources. Botswana’s water resources are threatened by various pollution sources such as agricultural runoff, industrial and domestic effluents.This study was carried out to assess the water quality of Dikgathong Dam in Botswana using physicochemical analysis of water quality parameters and remote sensing techniques.The study first assessed landuse patternsbefore construction (2010) and after construction (2015) to establish dominant landuse inorder to select water quality parameters related to the principal landuse in the catchment. Images for 2010 and 2015 were acquired from Landsat and were classified using the supervised classification through the Maximum Likelihood algorithm. Results showed that forest and shrubs were the dominant landuse covering 73.7 % of the total area, followed by settlements (21.1 %) and agricultural fields (2.76 %).Chl_a, COD, EC, TP, TN, TSS, NO3 and NO2 were selected for testing and analysis based on their relationship with forest, settlements and agricultural fields.For assessment of water quality, ten points were sampled in the dam from 15th January to 07th April 2016. Temperature,pH, EC, COD, TDS, TSS, turbidity, chloride, nitrates, sodium, potassium, calcium, magnesium, sulphates, phosphates, total phosphorus, alkalinity, hardness and algae were tested and analysedaccording to standard methods. Only COD, turbidity and TSSexceededthe limits set by Environmental Protection Agency (EPA)surface water standards of 2001, making Dikgathong Dam slightly polluted.One way ANOVA showed significant variations (p