6. Conclusions
The above analysis demonstrates the use of multivariate statistical techniques to study the source/genesis of chemical parameters in surface water systems. Though the two multivariate techniques provide powerful means of studying the source genesis of the hydrochemistry of the Basin, the HCA gives broader and less definitive classifications than the PCA since the clustering and interpretations based on the dendrograms are largely subjective. The PCA, with the varimax rotation, is much more definitive and provides much more insight into the processes controlling the hydrochemistry at the different locations along the Basin. The application of both the R-mode HCA and PCA with varimax rotation, however, has been more effective than the use of either one of them alone. The hydrochemistry of the basin is controlled largely by the weathering of minerals (silicates, carbonates, gypsum and apatite) from the underlying meta-sediments of the Birimian and Tarkwaian Systems, and the decay of organic matter from the heavily forested regions. There is no strong evidence of high anthropogenic impacts on the hydrochemistry of the basin, though there are variations at the different locations studied. The hydrochemistry at Ankwaso is principally controlled by the weathering of silicate minerals, whereas those of Dominase and Prestea are, respectively, influenced by precipitation and domestic wastewaters, and the decay of organic matter.