Spatial and Temporal Variations of the Physicochemical Parameters of the Water Quality of Lake Basaka, Oromia Region, Ethiopia

The water quality of Lake Basaka is currently influenced by natural and anthropogenic activities. The objective of this study was to examine the spatial and temporal variations in physicochemical water quality parameters in Lake Basaka. The water sample was collected in the dry and wet seasons for the verification of some selected parameters. Laboratory analysis was performed at the Abbay Basin Development Authority Water and Wastewater Laboratory. Statistical analysis of physicochemical parameters was used in the dry and rainy seasons during the year 2021. An analysis of variance (ANOVA) was performed to measure the significant spatio-temporal variation of the physicochemical parameters of water quality. The ANOVA results indicated that the physicochemical indicators of water quality have a significant variation with time and space. Spatial maps were also generated using the GIS (interpolation) tool to understand the spatial distribution of each water quality indicator in Lake Basaka. The result shows a high spatial variation of PH, EC, Na, F, and bicarbonate in the Abadir and Addis Ababa roadside. The temporal variation of the quality of Lake Basaka shows a decreasing trend due to the dilution of freshwater (runoff or hot springs) towards Lake Basaka. The water quality index (WQI) was used to assess the general state of the water quality of the lake for irrigation purposes. Lake Basaka's water quality index is 103.97, indicating poor water quality in the lake. In general, this document revealed that the water status of Lake Basaka is currently not suitable for any purpose due to poor quality, as a result, the expansion of the lake becomes a great challenge for the city of Metahara and the sugar plantation of Metahara from time to time.