Spatial evaluation of land use variability on water quality of the Densu Basin, Ghana

The effect of different land use types on the physicochemical water quality of a semi-arid coastal basin is examined. From nine (9) sites, a comprehensive sampling campaign was executed during October 2018 to January 2019. One-way ANOVA, Pearson correlation and multiple regression analyses were used to determine the relationship between water quality characteristics and land use types at the sub-basin and buffer-zone scales. The one-way ANOVA test indicated that most of the parameters are significantly different (p< 0.05) among the sampling sites with the exception of pH, total hardness (TH), nitrate-nitrogen (NO3-N), ammonia-nitrogen (NH3-N), dissolved oxygen (DO), chemical oxygen demand (COD) and iron (Fe). Agriculture and built-up/bare land had a positive relationship with turbidity, TSS, conductivity and Fe within 50 m and 150 m buffer zones. Built-up/ bare land showed a positive relationship with turbidity, TSS and Cl at the sub-basin scale. Forest cover correlated negatively with water quality although not significantly. Grassland correlated significantly with temperature, Cl and total hardness. Results of the multiple regression analysis indicate that land use types within the riparian buffer zones had greater impact on water quality than at the sub-basin scale. This work provides essential information for land use planners and water managers towards sustainable water resources management.