Lake Malawi is one of the world’s greatest fresh water lakes in the world. It is ranked number five of the world’s fresh water lakes based on its volume estimated to be 7775.00 km3. The lake has a biodiversity of up to 1000 aquatic species. Not only does the lake provide habitat to the aquatic life, it also provides economic as well as recreational services to the Malawian society. There has been growing concerns that the water quality in Lake Malawi is declining. These declines have been in both the absolute values
of the water quality parameters as well as the extents of the changes. These water quality declines have been attributed to anthropogenic activities on the lake’s catchment. These activities are in the form of agriculture and settlements. This paper assesses the changes in water quality, both absolute values and the coverage of the changes are used. The changes in the water quality parameters is determined by image differencing. The significance of these changes are established using Anova with a single factor. It is observed that there is significance in changes of water quality. When an attempt was made to determine whether there were seasonal variations, the results suggested that the variations were insignificant. Such a conclusion was based on the comparison of the P value and the alpha value. An attempt is also
made to assess changes in land cover. Land cover changes are indicative of human activities on the catchment. It is observed that there is an increase in human activities which are in the form of settlements and agriculture. The increase in these activities has led to the depletion of forest resources on the catchment. This is explained by the correlation coefficients on the outputs of the correlation analysis between the various land covers. A relationship between the changes in water quality and the changes in land cover is also established. However, there were weak relationships between absolute water quality parameter values and land cover changes except for forest resources versus Secchi Disk Transparency. The results suggested that reduction in
forest resources leads to a decline in water clarity. Stronger relationships were established when coverages of declining water quality were used against the land cover changes in the correlation analysis. The results suggested that human activities have played an upper hand in the depletion of forest resources on the catchment and has resulted in the decline in water quality in the lake.