Depth profile of reservoir water quality in the Southwest of Ethiopia

The objective of this research was to investigate the variation water quality parameters at different depths Gilgel Gibe I reservoir in Oromia Jimma zone during wet seasons. Five stations within were selected, and determined four (surface, 5 m, 10 15 m). Water analyzed on-site using a HACH, HQ40d portable multi-meter, turbidity measured Wag tech meter laboratory standard method. Comparison among conducted one-way ANOVA Tukey's pairwise comparisons with 5% significance level. probable contributing source investigated physicochemical depth identified Principal components analysis. results show that wise except for total suspended solids (TSS), dissolved (TDS), phosphorus (TP) soluble reactive (SRP) rest showed statistically significant difference p < 0.05 Negative correlations found between oxygen (DO), temperature, pH, nitrate (N03-) chlorophyll (Chl.a) while positive electrical conductivity (EC), biochemical demand (BOD5), N03-. study revealed release nutrients associated increased concentration BOD5 bottom caused low due consumption. This further aggravated through decomposition organic matter, indicating pollution resulting from runoff catchment. presence dense masses blue-green algae pelagic suggested ample its blooming reduction quality, possible eutrophic conditions. Therefore, catchment management is required protect aquatic life function as whole degradation.