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Many catchments in developing countries are poorly gauged/totally ungauged which hinders water resource management and flood prediction in these countries. This study explored the application of the PyTOPKAPI model to South African (Mhlanga) and Ethiopian (Gilgel Ghibe) case study catchments to test its suitability for simulating stream flows from ungauged catchments. The aim is to extend the model application to poorly gauged/totally ungauged catchments in developing countries. The model uses digital elevation data and other spatial data sources to set up the model parameters and the forcing files. To generate reliable stream flows, models generally need to be calibrated, which typically relies on the availability of reliable stream flow data. We show how application of simple lumped models for average runoff ratios, such as that proposed by Schreiber in 1904, can be used as an alternative to detailed calibration with gauged flows. This approach seems to be new; and we show how the proposed method, together with the PyTOPKAPI model, can be used to predict runoff responses in ungauged catchments for water resource applications and flood forecasting in developing countries.

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Trend analysis of hydrometeorological data is vital for proper water resources planning and management. This paper examines the trends of the hydrometeorological data in Gilgel Gibe catchment and whether the trends are significant. Daily rainfall, temperature, and streamflow data of the stations in/around (nearby) the catchment (7 stations for rainfall, 4 stations for temperatures, and 6 stations for streamflow) for a period longer than 25 years were collected and then analyzed to detect the variability and the changes in trend. Prior to conducting trend tests, the missed data were filled, and their inconsistencies were also adjusted. The nonparametric Mann-Kendall test along with Sen’s slope technique was employed to detect monotonic trends in the data series. The results showed that, on average, the rainfall exhibits an insignificant increasing tendency. It was also observed that there is, in general, an increasing trend in temperature (both maximum and minimum) in the study area. The analysis of the stream flows indicated that only one station (Bulbul Nr. Serbo) showed a positive slope at a 5% significance level. Two stations (Aweitu Nr. Babu and Gibe Nr. Seka) showed a slightly increasing trend, whereas the remaining 3 stations (Gibe Nr. Assendabo, Aweitu at Jimma, and Kitto Nr. Jimma) indicated an insignificant decreasing trend. The streamflow of the catchment generally shows a tiny decreasing tendency (0.007% per year) at its outlet. However, the results in general specified statistically insignificant trend changes of the hydrometrological data of the study catchment.

Electrocoagulation with ozone and photo is a hybrid electrochemical and AOP techniques used to treat wastewater and industrial effluent. In the present study, the effects of combining O3, UV, and EC processes on color removal as well as the related COD removal and EEC from the treatment of DIW were assessed. The results showed that, compared to other hybrid processes like O3/EC, UV/EC, UV/O3, and single processes of EC, O3, and UV, the combined process of O3/UV/EC is significantly more effective for treating DIW in terms of COD removal (98.99%) and complete color removal with a required EEC of 9.7 kWhr m-3. Number of process variables, including reaction time (1 to 5 hr), O3 (0.8 to 4 g L-1), UV (8 to 32 W), current density (0.08 to 0.23 A dm-2), pH (1 to 11), COD (1000 to 6000 mg L-1), inter-electrode distance (0.75 to 3.75 cm), and combination of electrodes were studied to analyze how they affected. The optimum operating circumstances underwent testing and shown outstanding effectiveness in eliminating the COD and determination of EEC from DIW. Overall, it was clear from the results that combined treatment approaches could be more effective in removing the pollutant successfully from DIW.