Selection of Optimum Pollution Load Reduction and Water Quality Improvement Approaches Using Scenario Based Water Quality Modeling in Little Akaki River, Ethiopia

The collective impacts of rapid urbanization, poor pollution management practices and insufficient sanitation infrastructure have driven the water quality deterioration in Little Akaki River (LAR), Ethiopia. Water modeling using QUAL2Kw was conducted LAR aimed at selecting optimal improvement load reduction approaches based on evaluation five scenarios: modification point sources (PS) (S1), nonpoint (NPS) (S2), simultaneous PS NPS (S3), application local oxygenators fish passages cascaded rock ramps (S4), an integrated scenario (S5). Despite S1 resulting average Biochemical Oxygen Demand (BOD) (17.72%), PO4-P (37.47%), NO3-N (19.63%), objective (WQO) could not be attained. Similarly, though significant found by S2 S3 evaluation, it did secure permissible BOD LAR. Besides, as part instream measure, a evaluated (S4) resulted load. All individual scenarios were successful hence integration (S5) that gave relatively higher pollutant rate ultimately better approach to improve loads river. In conclusion, control strategy integrally incorporating use source-based wastewater treatment, diffuse through best measures such feasible for river management, reduction, aquatic life protection sustainable development catchment.