Assessment of Effects of Turbidity Variation on Water Temperature and Evaporation of Gilgel Gibe I Reservoir, Omo-Gibe River Basin, Ethiopia

Abstract

Turbidity has a significant impact on reservoir water by raising the temperature and evaporation rates. This study provided clear and concise information about the effects of turbidity alteration on reservoir water. The main objective of this study was to assess the effects of turbidity variation on reservoir water temperature and evaporation. To determine these effects, the samples were taken from the reservoir by stratifying it randomly along the reservoir course. To evaluate the relationship between turbidity and water temperature and also to measure the vertical alteration of water temperature, ten pools were burrowed, and they were filled with turbid water. Two class A pans were installed in the field to determine the effect of turbidity on reservoir evaporation. The data were analyzed using SPSS software and MS Excel. The results depicted that turbidity has a direct, solid positive relationship with water temperature at 9:00 and 13:00 and a vigorous negative relationship at 17:00, and water temperature decreased vertically from the top to the bottom layer. There was a greater extinction of sunlight in most turbid water. The differences in water temperature between the top and bottom layers were 9.78°C and 1.53°C for most and least turbid water at 13:00 observation hour, respectively. Turbidity has a direct and strong positive relationship with reservoir evaporation. The relation was analyzed using Spearman’s ranked correlation coefficient, and the vertical alteration of water temperatures was analyzed using a box and whisker plot. The tested results were statistically significant. The study concluded that an increment in reservoir turbidity immensely heightens both reservoir water temperature and evaporation.