Accurate measurement of precipitation is vital to investigate the spatial and temporal patterns of precipitation at various scales for rainfall-runoff modeling. However, accurate and consistent precipitation measurement is relatively sparse in many developing countries like Ethiopia. Nevertheless, satellite precipitation products may serve as important inputs for modeling in an area with scarce field data for a wide range of hydrological applications. In this study we evaluate the high-resolution satellite rainfall products for hydrological simulation, the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) and Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis (TMPA_3B42v7) satellite rainfall products for stream flow simulation at daily temporal and 0.25° × 0.25° spatial resolution. The study area is located in Dabus watershed, Abbay basin, Ethiopia. We applied a nonlinear power law to remove the systematic error of satellite precipitation estimates for input into HEC-HMS hydrological model for runoff generation. The performance of the satellite rainfall and hydrological model was evaluated using Nash–Sutcliffe efficiency (ENS), coefficient of determination (R2), relative volume error (RVE), and percentage error of peak flow objective functions. The result of HEC-HMS model performance revealed R2 of 0.78, ENS of 0.69 for CHIRPS_2 and R2 of 0.79, ENS of 0.76 for TMPA_3B42v7 satellite rainfall products during calibration periods. Our result indicated that the HEC-HMS model well predicated catchment runoff for both satellite precipitation products. The study shows that the model performance was significantly improved when bias-corrected satellite rainfall input replaced than the original uncorrected satellite products. Overall, our study showed that gauge-based simulation outperformed than satellite in terms of all objective functions over the study area.

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In Ethiopia soil erosion and land degradation has become a key issue, because of roughed and steep slope topography that soil erosion become accelerating. The main objective of this study was to identify soil erosion hotspot areas in Dengora and Meno watersheds using Revised Universal Soil Loss Equation (RUSLE) and Multi Criteria Decision Analysis (MCDA) techniques. To achieve such objective RUSLE model was used to estimate potential soil losses by utilizing information on Soil, land use/cover, topography, and climatic data. MCDA technique considered land use, soil type, topographic wetness index, stream power index and potential location of gullies. The factors were weighted using pair-wise comparison matrix and weights were combined using Weighted Overlay. Based on RUSLE model, the average annual soil loss of Dengora and Meno watersheds were reaches up to 223.97and 256.09-ton ha-1yr-1 respectively. In Dengora watershed 70.4%, 18.7%, 10.74% and 0.14% and Meno watershed 76%, 16.54%, 7.3% and 0.14% of the total watershed area slightly, moderately, highly and very highly sensitive to soil erosion respectively. On the other hand, GIS based MCDA technique reveals that in Dengora watershed 9.7%, 64.5%, 18% and 7.8% and Meno watershed 6.1%, 71.3%, 23.23% and 0.375% of the total watershed area was highly, moderately, slightly and currently not sensitive to soil erosion respectively. Based on validation, field level observation, MCDA model prediction was more accurate than RUSLE. Both of the watersheds were at moderate risk. Bottomlands of the watersheds under were highly sensitive areas for erosion. Therefore, immediate attention for soil and water conservation practices.

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The objective of this study is evaluating channel stability investigation and recommend appropriate mitigation measure of Mersa river, Awash basin Ethiopia. HEC-RAS5.0.7 model with BSTEM (its extension) was used for assessing Mersa riverbed and bank stability and identifying flood prone area. To achieve the objective both filed investigation such as river cross section data collected, soil sample taken and experimental tasks such as sieve analysis, triaxial compression test are carried out. HEC-RAS model simulation with Yang sediment transport formula is best representative for study reach as compared to Meyer Peter and Muller sediment transport method. For entire simulation period an average aggradation was 1.24m and 0.98m at upstream and downstream reach respectively, whereas average degradation on both upstream and downstream reach was 1.25m. The average erosion generated from Mersa river was 22.47kt/yr. Both aggradation and degradation were observed on the study reach but Mersa river reach more affected in erosion than deposition. Mersa riverbank stability and toe erosion assessed by BSTEM of HEC-RAS was safe and again bank toe neither aggrade nor degrade in response to the flow. Additionally, Water surface of Mersa river was computed using steady flow analysis shows that flood over top above the bank, adjacent area (Mersa town) was severed by flood and the reality also true. The reality also true especially due to flood loss their farmland and different property. Finally, this investigation presented that channel bed was unstable while bank was stable. Different stabilization measures like Gabion bank, Check dam and drop structure were recommended to prevent flood prone area from flood and to control channel bed instability.