Ethiopian Journal of Water Science and Technology最新文献

{"title":"Evaluation and risk Assessment of potentially toxic trace metals in water, sediment and fish from the City of Addis Ababa, Central Ethiopia","authors":"Alemnew Berhanu, T. Berhanu, J. Okonkwo, S. Leta","doi":"10.59122/134d6b2","DOIUrl":"https://doi.org/10.59122/134d6b2","url":null,"abstract":"Because of fast urban expansion and increased industrial activities, large quantities of solid and liquid wastes contaminated by trace metals are released into the nearby water bodies situated in Addis Ababa. Greater Akaki River (GAR) and Little Akai River (LAR), which join at Aba Samuel Reservoir, are the main rivers draining the city. Eleven (11) water, 11 sediment and 18 fish samples were taken and tested for the level of trace metals content, distribution, pollutionlevel, bioaccumulation, possible sources of pollutants and associated ecological risk. Trace metals were tested using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). USEPA guideline values, geo-accumulation index, contamination factor, and pollution load index were used to evaluate contamination levels and eco-toxicity. The results indicated that the mean concentration of Cr, Fe, Mn and Ni in water samples and Cd, Pb, Mn, Ni and Zn insediment samples exceeded their respective background values. Besides, the levels of Cr, Fe, Mn, Ni and Pb in the muscle of Clarias gariepinus were above the permissible limits for human consumption. Furthermore, ecological risk assessments using sediment samples revealed the widespread pollution by Cd and Pband moderate pollution by Mn, Ni and Zn. A comparison with similar studies revealed that sediments from the study area had the highest average value of Pb. Generally, the study indicated that Akaki River catchment and Aba Samuel Reservoir were found to be moderately to strongly contaminated by heavy metals and thus posed high ecological risks.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122454621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating the extent of soil degradation of Weito Watershed in lower Rift Valley Basin: Southern Ethiopia","authors":"M. Ayana, Aschalew Cherie Workineh, A. Mohammed, Samuel Dagalo Hatiye","doi":"10.59122/1355047","DOIUrl":"https://doi.org/10.59122/1355047","url":null,"abstract":"In this study, Revised Soil Loss Equation (RUSLE) was used to quantify the potential soil erosion in Weito Watershed. Rainfall data, soil data, DEM data and landuse-land cover data were used as input data sets to generate RUSLE factor values. RUSLE factors such as R_ the erosivity factor, K_the soil erodibility factor, LS_ thetopographic factor, C_ the crop management factor, and P_ the conservation support practice was analyzed and superimposed using raster calculator in ArcGIS10.1 to estimate and map the annual soil loss. The results showed annual soil loss ranging from 0 to 210 tons/ha and mean annual soil loss rate of 110ton/ha/yr. The annual soil loss rate in the western and south western part of the watershed was mainly identified as high and severe and hence, requires special attention with an immediate soil conservation practice.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124974409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of onion (Allium CepaL.) to soil moisture stress condition at different growth stages in the central Highland Vertisols Areas of Ethiopia.","authors":"Ashebir Haile, Gebeyehu Tegenu, Solomon Gezi","doi":"10.59122/135610e","DOIUrl":"https://doi.org/10.59122/135610e","url":null,"abstract":"Improving water use efficiency is an important strategy for addressing future water scarcity. Therefore, enhancing agricultural water productivity is a critical response since agriculture is the main consumer of global fresh water. The main objective of this study was to identify sensitive growth stages of onion to soil moisture stress, to determine the critical time for irrigation water application and water use efficiency for onion. The field experiment was conducted for threeconsecutive seasons (2015 – 2017) at main station of Debre Zeit Agricultural Research Center. Fifteen treatments were used. It is arranged by stressing application of the crop water requirement during irrigation event with combinations of four growth stages of onion. All treatments were laid out in randomized complete block design with three replications for each treatment. The result revealed that onion bulb yield and water use efficiency were significantly affected at p< 0.05 bydepriving irrigation water at growth stages among the all treatments. The highest bulb yield (23.8 t/ha) was observed from no stress (control) treatment and followed by stressing at initial (22.7 t/ ha) and at maturity stage (21.6 t/ha) with no statistical difference with control. However, the lowest yield was recorded at stressing all stages of the crop growth period except development (6.7 t/ha). There was also a significant differences of water use efficiency (WUE) detected among the treatments. However, the highest WUE (13.84 kg/m3) had been recorded at stressing all stages except initial. Under irrigated onion production, the mid-stage should be regularly monitored as it significantly affects the yield of onion. Besides, in the areas where irrigation water is limited, limiting the amount of water applied during development and maturity sage is the best solution to enhance water productivity without significantly reducing the bulb yield of irrigatedonion.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131209984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of furrow irrigation system on pepper (MelkaShota) production at Tanqua Abergelle district, Tigray, Ethiopia","authors":"E. Tariku, G/ Kiros Gebremedihin","doi":"10.59122/134110c","DOIUrl":"https://doi.org/10.59122/134110c","url":null,"abstract":"The field experiment was conducted in north Ethiopia, Tigray at sub-district called Sheka-tekli. The objective of the study was to evaluate the performance of furrow irrigation systems on pepper production. The furrow irrigation treatments were i) Conventional Furrow (CF), ii) Alternate Furrow (AF), and iii) Fixed Furrow (FF). The experimental design was a randomized complete block design (RCBD) with three replications. The climatic data were obtained from Ethiopian Meteorological Agency and New_LocClim software. The crop water requirement and irrigation scheduling were estimated using Cropwat8 software. The collected agronomic data were subjected to one way ANOVA while irrigation water related performances indicators were computed using equations. Accordingly, the fresh pepper yield for CF (12250 kg h-1) and AF (9670 kg h-1) were not significant different. However, there was significant difference between CF and FF methods of furrow irrigation. The fresh crop yield for FF was 7670 kg h-1. The water savings from AF and FF methods of irrigation as compared to the CF method was 30.62%.The economic irrigation water productivity was higher in AF (5.33 ETB m-3) than CF (4.68 ETB m-3) and FF (0.49 ETB m-3). Irrigation water productivity was 1.95 kg m-3, 2.22 kg m-3 and 1.76 kg m-3 for CF, and AF and FF methods of irrigation, respectively. Thus economic irrigation water productivity and environmental benefits foralternate furrow irrigation method (AF) was much superior as compared to other furrow irrigation methods.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128076459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Land Use/Land Cover Change on Watershed Hydrology: A Case Study of Upper Awash Basin, Ethiopia","authors":"Samuel Beyene, Abdella Kemal, Santosh Murlidhar","doi":"10.59122/13529d1","DOIUrl":"https://doi.org/10.59122/13529d1","url":null,"abstract":"Land use/land cover (LULC) change is one of the important factors which have direct impacts on watershed hydrology. The impact of LULC change on streamflow of Upper Awash watershed was carried out using Soil and Water Assessment Tool (SWAT). The LULC change analysis was performed by using unsupervised classification method using Earth Resources Data Analysis System (ERDAS) imagine 8.5 software. The study results showed that the watershed experienced significant LULC change during 1986 to 2009. SWAT model was calibrated for periods 1986 to 1999 and validated for the periods 2000 to 2009. SWAT model was calibrated and validated for the sensitivity of streamflow parameters. Consequently, ten parameters were identified to be sensitive. Further, this model was utilized to assess the impact of LULC change on streamflow for period 1986 to 2009. The result showed that there was a reasonable agreement between observed and simulated streamflow with coefficient of determination (R2) and Nash-Sutcliffe efficiency values 0.86 and 0.77 for calibration, and 0.84 and 0.76 for validation, respectively. The evaluation of SWAT hydrologic response unit (HRU) due to LULC change showed that monthly streamflow was increased by 16.13 % in wet months and decreased by 20.8 % in dry months between the years 1986 and 2000. While between the year 2000 and 2009, it was increased by 0.92 % and 5.82 % for wet and dry months, respectively. Similarly, surface runoff was found increased and groundwater decreased during the study period. Further, the calibrated model can be utilized to understand risk and reliability of different structures and analysis of climate change, water quality, and sediment yield. Hence, this type of study can be useful for sustainable development in the Upper Awash basin as well as in other regions of Ethiopia.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129269229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water Purification with Direct Solar Desalination for Arid Areas in Ethiopia","authors":"Jibril Hussien, K. Kassa, B. Mogesse","doi":"10.59122/1356893","DOIUrl":"https://doi.org/10.59122/1356893","url":null,"abstract":"The use of solar energy in thermal desalination processes is one of the most promising applications of in water purification. Solar desalination can either be direct; use solar energy to produce distillate directly in the solar collector, or indirect; combining conventional desalination techniques, such as vapor compression (VC) and multistage flash desalination (MSF), with solar collectors for heat generation. This paper describes a pilot study of direct desalination technology. The pilot experiment of desalination system was made up of a single basin (1.5m x 1.8m basin area) and two sided roof with 15 degree to the horizontal and sealed roof of 4 mm thick glasses. The glass cover roof was positioned from East to West orientation and obstruction free area to increase the efficiency of available sunlight utilization. Water quality parameters of the water and treated water were tested at Arba Minch University Water quality Laboratory. The study revealed that, the average yield of the distillate water was 2.6 L/m2/ day, where the average efficiency of the system was 29.5 %.Regression analysis showed that climatic variables such as temperature, wind speed and solar intensity were observed to affect the treatment efficiency of the production of distilled water in this pilot study. Accordingly, the experiment output transposed to Dollo Ado, Somali Regional state and the solar still was predicted to produce 3.4 - 5 L/m2 /day with climate condition of the area. Although the system requires large area with relatively low production, it is still suitable for use in remote and arid with high temperature.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128267700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate Change Impact on Water Resources Availability of Finchaa-AmertiNeshe Multipurpose Cascaded Reservoirs","authors":"Sisay Simachew, Samuel Dagalo Hatiye","doi":"10.59122/13544e3","DOIUrl":"https://doi.org/10.59122/13544e3","url":null,"abstract":"The most profound effect of climatic change may be alterations in the regional hydrologic cycle and changes in regional water availability. Besides the increasing water scarcity, climate change threatens to exacerbate the current supply-demand imbalance. In this study, the impact of climate change on water availability and reliability to satisfy the increasing demand under changing the climate on Finchaa sub-basin has been evaluated using the Water Evaluation and Planning(WEAP) model. WEAP package was utilized to simulate the future water availability using the runoff generated by the Hydrologiska Byråns Vattenbalansavdelning (HBV) model as an input. The performance of the model was assessed using statistical tools such as Nash and Sutcliffe efficiency criteria (R2) and the Relative Volume Error (RVE) during model calibration and validation steps. R2 values were greater than 0.8 and RVE values were near 0 for all the three sub-catchments showing the better performance of the model. The prediction for future climate variables, on the other hand, showed an increasing trend for both maximum and minimum temperature values. However, for precipitation, it doesn’t manifest any systematic increasing or decreasing trend in the next three decades. Consequently, the total water availability in the study area is expected to decrease by 11.88% in the next thirty years. Compared to the base scenario, the simulated future inflow to Finchaa and Neshe reservoirs has shown a slight increment at the end of 2025 and a small decrease at the end of 2040. However, the simulated future inflow volume to Amerti reservoir has shown a likelihood of small and considerable decrease at the end of 2025 and 2040, respectively. Considering the future expansion in the study area, all future and existing demand sites in the study area may be fully satisfied with 100% demand site coverageand 98.89% demand site reliability under changing the climate. Finally, it can be concluded that even though the demand in the sub-basin is increasing greatly, the available water resources is expected to be satisfactory under changing climate conditions for the next thirty years.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126965699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Farmer’s Perception about Water Demand and Availability in Koga Irrigation Project Under Climate Change","authors":"B. Berhanu, A. Haile, K. Getnet, Y. Amha","doi":"10.59122/13431e1","DOIUrl":"https://doi.org/10.59122/13431e1","url":null,"abstract":"Irrigation is certainly a means for farmers to adapt to climate variability and change. However, the impact of climate change on irrigated agriculture and possible options to deal with it still deserves more research. We therefore assessed farmer‟s perception on climate change and its impact on current and future water management in the Koga irrigation scheme in Lake Tana sub-basin, source of upper Blue Nile River. Farmers in Koga who used to entirely rely on rain fed agriculture stated that the major benefits of the scheme are multiple cropping, increased productions and profits, savings, children‟s school enrollment and in general better livelihoods. Despite these observed benefits more than half of the respondents expressed dissatisfaction with the current water allocation.  Farmers are concerned that climate variability and change might exasperate the current water allocation issues. For example, hail strom was cited as one of the major climate stress in the region by 60% of respondent. Seven out of ten respondents felt a change in rainfall pattern (onset and variability) in the past 20 years.Slightly less than half of the farmers believe that temperature has increased over the past two decades. More than half of the farmers anticipate future water shortages due to climate change and sedimentation. Almost all of the respondents do not use other water sources during times of water shortage. The main reasons for not using additional source of water are long distance from river water, and long distance between existing hand dug groundwater wells and cultivated lands. About 38%, 12% and 12% of the respondents suggest respectively digging groundwater wells, rainwater harvesting and improved governance as better strategies to deal with future water shortage. Measures that will solve existing water allocation problems and enable farmers to better deal with the anticipated future water shortages will increase the resilience of the scheme.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128204343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Local Scour at Bridge Piers: the Case of Failure of Kulfo River Bridge at Arba Minch, Southern Ethiopia","authors":"N. Girma","doi":"10.59122/1342721","DOIUrl":"https://doi.org/10.59122/1342721","url":null,"abstract":"The scouring of the streambed around bridge piers can be caused by the characteristics of the stream itself, due to the contraction of the flow by the bridge crossing and/or due to other human interference upstream and downstream of the crossing. Kulfo River Bridge failure in October 1997 due to excessive scour under one of the piers after a flood event is one typical case. It was known that excessive sand/gravel was being extracted for construction purposes prior to the failure. To determine the extent and specific cause of the failure, river survey, bed material sampling and simulation of the pier scour under different river bed scour scenarios were conducted. From the bed material sampling, the grain size was found to vary from very fine sand to small cobbles, showing that the bed is in the coarse-grained class – gravel bed alluvial river. Simulation of the pier scour was done using BRI-STARS (Bridge Stream Tube Model for Alluvial River Simulation) model. The model was calibrated in two phases: (i) calibration of hydraulic parameters, and (ii) calibration of sediment transport parameters.Measured water surface elevations and Manning’s roughness coefficient were used as calibration parameters. Among the two gravel/sand mining scenarios (wet-pit mining from the active channel, and bar skimming or scalping above low water level) simulated, the wet-pit mining resulted in maximum scour under the bridge pier when it is followed by a 100-year flood and consequent failure. This result shows that sand/gravel extraction operations within or near the streambed have direct impact on the stream morphology and river structures.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133706412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}