Eutrophication is the enrichment of water body by nutrients; especially nitrates and phosphates.rnThese nutrients are used by phytoplankton such as algae and Cyanobacteria. High nutrientrnconcentration cause algal bloom; if this is Cyanobacteria; it creates a big health problem tornhuman and cattle depending on drinking water reservoirs by releasing toxic substance. This studyrninvestigates and quantifies the nutrients at Dire reservoir so that it is easy to identify the potentialrnsource of nutrients to the Dire reservoir which was constructed by Addis Ababa Water andrnSewerage Authority for drinking water supply. Furthermore, the trophic status of the reservoirrnwas identified in comparison to the amount of Chlorophyll-a. In doing so, Reconnaissancernsurvey was made through systematic stratified sampling design where the soil, sediment andrnwater in and around the reservoir and the tributaries flowing to the reservoir were sampled andrnanalyzed in the laboratory for their nitrate and phosphate contents. A total of 22 waters, soil andrnsediment samples were taken for each of the sample types namely: water, sediment and soil inrnDecember and February, dry season. These were one from upstream and another fromrndownstream of the tributaries flowing towards the reservoir such as Legedadi, Silmicha andrnBerek. In addition, five soil, five sediment and five water samples were taken inside and aroundrnthe reservoir independently for the two months. The data obtained are tabulated to be analyzedrnusing Microsoft Excel and SPSS software. Accordingly, analysis of variance and correlation ofrnthe parameters are evaluated. There is high nutrient deposition in the sediment compared to thernsoil and water; it is more concentrated at the downstream than the upstream of the tributariesrnwhich are an indication of erosion of upstream soil during the rainy season and aggravated byrncrop cultivation in the watershed. Surprisingly, the chlorophyll- a concentration (0.35Î¼g/l) is notrnas much as the nutrients due to low light penetration. The reservoir is phosphorus limited and isrnhyper- eutrophic. The nutrients in the reservoir are mostly contributed by sediments of Legedadirn(18.6mg/kg) and Silmicha (34.9mg/kg) Rivers. Hence, IWM must be applied by the stakernholders paying attention to Silmicha followed by Legedadi and Berek tributaries.rnKey words: Nitrates, Phosphate, Sedimentation, Eutrophication