Ethiopian Journal of Water Science and Technology最新文献

{"title":"Impacts of Climate Variability on Livestock Resources and Pastoralist Adaptation Responses in Dollo Ado Woreda, the Case of Ethio-Somali National Regional State.","authors":"Degu Zewdu","doi":"10.59122/13578db","DOIUrl":"https://doi.org/10.59122/13578db","url":null,"abstract":"This study was conducted in Dollo Ado Woreda of Ethio- Somali-National-Regional State. The general objective of this study was to understand the impacts of climate variability on livestock system and pastoralist adaptation responses in DolloAddoWoredaEthio -Somali National Regional State. Rainfall and temperature data for 34 years were collected from three meteorological stations. Socio-economic data were collected using a structured esquestionnaire from150randomly selected sample households from three kebeles. Data were organized in excel and analyzed using Statistical Package for Social Scientists (SPSS)and analyzed using descriptive statistics. Coefficients of variation (CV), Precipitation concentration index (PCI), and standardized rainfall anomalies (SRA) were calculated for the period 1983 - 2019. Livestock-related information was gathered from Dollo Ado Woreda Animal Science Department. Then regression and correlation were computed between annual rainfall amount and temperature total over the study period. The findings for this study indicated that both rainfall and temperature over the study area had shown high spatial and temporal variability. The average annual precipitation concentration index (PCI) showed an irregular distribution of annual rainfall for all stations. The results also indicated that the study area has experienced several drought events and flood years with different magnitudes. The number of livestock population was positively associated with annual rainfall. While most livestock populations (except Camel and Goat) were negatively associated with mean annual temperature over the study area. Adaptation practices included mobility, destocking, livestock diversification, shifting from pastoralist to agro-pastoralist, and external support. Factors affecting pastoralist adaptation decisions were; age and sex of household head, family size, educational background, access to credit, and access to extension services training. Based on the results, it is recommended that households should use the most drought tolerant animals and as well as diversify their income. It is also better to use small-scale irrigation with the two rivers (Dawa and Genalle) instead of rearing only livestock.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114412557","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":"Application of AquaCrop and CropWat Models for Estimating Crop Water Requirement and Irrigation Scheduling of Maize in Metekel Zone, Ethiopia","authors":"Demeke Tamene Mitiku, A. H. Tefera","doi":"10.59122/13518ef","DOIUrl":"https://doi.org/10.59122/13518ef","url":null,"abstract":"The objective of the study was to compare AquaCrop Model with CropWat Model to estimate crop water requirement and irrigation scheduling of maize in the Metekel Zone. It also tries to compare the efficiency of Models for adoption in different situations in the study area. Crop water requirement and irrigation scheduling of maize in the study area were estimated using the CropWat Model based on soil, crop, and meteorological data. However, AquaCrop Model wasbased on soil, crop, and meteorological data including Co2, groundwater, field management, and fertility management condition. From the study, it was observed that the maximum reference evapotranspiration in the study area was found to be 7.1 mm/day in Guba and the minimum reference evapotranspiration was 2.9 mm/day in the Bullen district. The maximum ETo in all districts was found to in March and the lowest in August. The maximum ETc of maize was foundto be 702.4mm in the Guba district and the minimum ETc was found to be 572.6mm in Bullen district using CropWat but the effective rainfall for maize was determined as 185mm in the Wembera district. However, using the AquaCrop Model the maximum ETc of 565 mm was recorded in Guba but 425 mm was recorded as a minimum in the Wembera district for irrigated maize in the study area. From the study, it was observed that irrigation scheduling with a fixedinterval of 10 days with 12 irrigation events performed best. Moreover, the result revealed that there was a strong relationship and a significant relation between the simulated and observed values for validation. The model performance indicators showed that AquaCrop Model was well simulated in all parameters considered. Therefore, AquaCrop Model was found to be the most suitable soil-water-crop-environment management Model. So future studies should focus onaddressing deficit irrigation strategy with different field management conditions to improve agricultural water productivity under irrigated agriculture for the study area for major crops.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121710529","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":"Seasonal effect on the accuracy of Land use/Land cover classification in the Bilate Sub-basin, Abaya-Chamo Basin, Rift valley Lakes Basin of Ethiopia.","authors":"Alemeshet Kebede Yimer, A. Haile, Samuel Dagalo Hatiye, Assefa Gedle Azeref","doi":"10.59122/134c842","DOIUrl":"https://doi.org/10.59122/134c842","url":null,"abstract":"A correct and timely land use/land cover (LULC) classification provides indispensable information for the effective management of environmental and natural resources. However, earlier studies mapped the LULC map of Bilate Sub-basin using remote sensing images that were acquired for a single season. Hence, these studies did not consider the seasonal effects on the accuracy of LULC classification. Therefore, the objective of this study was to evaluate changes inclassification accuracy for images acquired during wet and dry seasons in the Bilate Sub-basin. LULC of the study area was classified using the Landsat 8 satellite imageries. Based on field observations, we classified the LULC of the study area into 9 dominant classes. The classification for the two seasons resulted in a noticeable difference between the LULC composition of the study area because of seasonal differences in the classification accuracy. The overall accuracy of theLULC maps was 80%for the wet season and 90% for the dry season with Kappa coefficient values of 0.8 and 0.9 respectively. Therefore, the two seasons showed a significant difference in the overall accuracy of the classification. However, we discovered that when the classification accuracy was tested locally, that is for individual pixels, the results were not the same. In Bilate Sub-basin, several pixels (14.71%) were assigned to different LULC classes on the two seasonsmaps while 85.29% of the LULC classes remained unaltered in the two maps. According to the classification results, the season had a noticeable effect on the accuracy of LULC classification. This suggests that for LULC classification, multitemporal images should be used rather than a single remote sensing image.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116881552","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":"Can We Model Floodplain Inundation Patterns in Data-Scarce Areas?","authors":"Mehari Gebreyohannes Hiben, G. di Baldassarre, A. van Griensven","doi":"10.59122/135811f","DOIUrl":"https://doi.org/10.59122/135811f","url":null,"abstract":"This paper proposes a methodology to model floodplain inundation patterns in data-scarce areas by using global remote sensing data. In particular, MODIS data are used for hydraulic model (HEC-RAS) calibration and validation purposes which is coupled with Geographic Information System (GIS) to map flood extent areas, while NASA's SRTM is used to describe floodplain topography. The Fogera floodplain (the upper Blue Nile in Ethiopia) is used as an example application to illustrate the methodology. To this end, parameter and input uncertainty is explicitly taken into account and visualized via probabilistic floodplain maps of the ensemble simulation. In view of that, model performance, reliability, and predictive uncertainties are critically discussed. This approach revealed that abetter characterization and visualization of the flood hazard. Also, the study investigates the impact of land-use changes on floodplain inundation patterns using a SWAT modeling system and the propagation of this land-use change in flood inundation patterns is seen again via probabilistic flood maps. This helps planners to use remote sensing data to model and monitor flooding.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124562245","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":"Modeling Long-Term Water Allocation and Analysis of Alternative Strategic Scenarios in the Catchment Area of Bilate River, Rift Valley Lakes Basin, Ethiopia","authors":"Desalegn Laelago, S. Tekleab, M. Dananto","doi":"10.59122/134aa4c","DOIUrl":"https://doi.org/10.59122/134aa4c","url":null,"abstract":"A water shortage stress might have resulted from the extensive water resources development plan in the Bilate catchment owing to the rapidly growing population, irrigation development expansion, climatic variability, and socioeconomic development. Furthermore, the lack of sufficient knowledge about available water resources and lack of coordination in water resources management skills in the basin often aggravates the competition of fixed waterresources among the users. Therefore, modeling long-term water allocation should be implemented to determine the optimal allocation of water resources, maximize the overall benefits without compromising ecological requirements, and propose mitigation measures that may alleviate the problem of water scarcity during peak demand periods. The Water Evaluation and Planning (WEAP) model is generally used in the formulation and evaluation of alternative plansfor responding to water-related problems and water resources developments. To assist in the assessment of spatialtemporal streamflow simulations within watersheds, the Soil and Water Assessment Tool (SWAT) employed in the Bilate River and its sub-catchments. The Indicators of Hydrologic Alteration (IHA) and CROPWAT 8.0 software programs were used to estimate streamflow requirement (IFR) and the crop water requirement, respectively. Three development scenarios include the agricultural and socio-economic development effect, climatic change, and alternatives that were built in the long-term planning horizons (2013-2050). The modeling water allocation for each sub-catchment was done by considering the Ethiopian water allocation and apportionment criteria and water act priority order. The result revealed that agriculture growth (increasing irrigation projects) and socio-economic development caused a significant increase in water demand. Hence unmet water demands in different parts of the catchments were increased. Similarly, the effect of climatic variation scenarios has been increased unmet demands in the middle year of the planning horizon(2030-2050). Therefore, developing adaptation strategies scenarios helps to mitigate water scarcity and improve water availability for productive use.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134059730","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":"Optimal Irrigation Scheduling of Garlic (Allium sativum L.) using Allowable Soil Moisture Depletion for Water Scarce Areas of Ethiopia","authors":"A. H. Tefera, S. Kebede, Gebeyehu Tegenu Mola","doi":"10.59122/1350a01","DOIUrl":"https://doi.org/10.59122/1350a01","url":null,"abstract":"The main objective of this study was to evaluate the responses of garlic to the irrigation regime (when and how much) to irrigate. The field experiment was conducted at the main station of Debre Zeit Agricultural Research Center in 2016 and 2017. Five treatments for allowable soil moisture depletion levels (ASMDL) of irrigation at 60%, 80%, 100%, 120%, and 140% were used. Application of irrigation water for garlic was scheduled when 30% of the total water available in the soil profile was depleted. Treatments’ were laid out in RCBD experimental design with three replications for each treatment. In the study, it was observed that there was a significant difference in marketable yield and water use efficiency (WUE) between treatments. The maximum marketable bulb yield (7.5 t/ha) and WUE were observed by applying irrigation water at 20% more than the recommended ASMDL and the lowest (4.68 t/ha) was recorded at 40% less than the recommended ASMDL. Reducing the allowable soil moisture depletion level by 40% and also by 20% from the recommended fraction (0.30) has significantly increased the water use efficiency. Generally, from this study it has been observed that irrigating garlic at a shorter frequency enhance yield and water productivity. Therefore, managing the soil moisture content above the allowable depletion level (i.e 60% ASMDL and 80% ASMDL) was better than using the recommended allowable depletion and the other lower levels. Hence, to have a higher yield and maximum water productivity, it was recommended to irrigate garlic frequently.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116095167","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":"Regionalization of Conceptual Rainfall-Runoff Model Parameters for Predicting Stream Flows of Ungauged Catchments in the Upper Blue Nile Basin","authors":"A. L. Akawka, A. Haile, D. W. Goshime","doi":"10.59122/1352681","DOIUrl":"https://doi.org/10.59122/1352681","url":null,"abstract":"Water resources development and research significantly suffered from lack of stream low data. Regionalization of model parameters was found veryuseful in filling such data gaps. We therefore regionalized the parameters of the HBV model so that the model could be used in ungauged catchments ofthe Upper Blue Nile (UBN) basin. Although we collected stream flow data for 76 stations from the Ministry of Water, Irrigation and Electricity, our dataquality assessment indicated that only 20 stations were suitable for calibrating the HBV model. We calibrated the model using hydro-climate data of 6 years and validated the calibrated model for independent data of 4 years. The calibrated model reproduced the overall pattern and base flow of the catchments. However, it noticeably missed several peak flows. The values of the calibrated parameters varied with the characteristics of the catchments. We therefore developed a multiple regression relationship between the parameters and catchment characteristics for the basin. The relationship was statistically significant and therefore could be used to apply the HBV model for un-gauged catchments in UBN for water balance studies, climate change impact assessment, and recharge estimation. However, additional work specifically improved data sets were needed to improve the regionalization results for peak flows.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"39 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130733991","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 coagulant type and magnetic ion exchange (MIEX) pre-treatment on floc strength and structure at the Kluizen Water Treatment Plant, Belgium","authors":"Gizeshwork Tadesse Gurmu, A. Verliefde","doi":"10.59122/13401d4","DOIUrl":"https://doi.org/10.59122/13401d4","url":null,"abstract":"Drinking water supplied to the community should be free from Disinfection ByProducts (DPB). DPB occurs when organic matter is present in surface water and reacts with chlorine. Conventional coagulation and flocculation processes have been used in water treatment plants to remove organic matters from raw water. Recently, Magnetic Ion Exchange (MIEX) followed by coagulation and flocculation has started to attract attention since it improves natural organic matter removal and decreases coagulant demand. The efficiency of NOM removal and downstream processes not only depends on the prior removal process of organic matter but also on the structure , size and strength of flocs formed in the coagulation process as well. This study aims at comparing (1) floc structures (i.e. floc sizes, floc strength, and fractal dimensions) generated from coagulation of raw water and (2) water pre-treated with magnetic ion exchange obtained from Kluizen water treatment plant (Kluizen, East-Flanders, Belgium). The floc sizes during growth, breakage and re-growth were measured using (laser) light scattering (Malvern Mastersizer 2000), coupled with jar test equipment. The strength of flocs was evaluated by empirically relating the floc size to the increased shear rate applied. The results show that pre-treated water coagulated with all the coagulants produces flocs with larger sizes compared to the flocs generated from raw water. For both water types, FeCl3 gave better recoverability after breakage than PACl and AlCl3. After pre-treatment, the floc size was increased by 19%, 63% and 64% forthe coagulants such as PACl, AlCl3, and FeCl3, respectively. Coagulation process with PACl generated flocs with higher fractal dimension and lower strength constants which indicates that flocs generated is strong and compacted micro-flocs. The floc size measurement techniques and coagulation system were found to have an impact on the resulting floc sizes.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116059550","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":"Quality of hydro-meteorological data in remote stations: the case of Weito river watershed, Ethiopia","authors":"M. Ayana, A. Mohammed, Samuel Dagalo Hatiye, Aschalew Cherie Workineh, F. Worku","doi":"10.59122/13414b1","DOIUrl":"https://doi.org/10.59122/13414b1","url":null,"abstract":"Engineering studies of water resources development and management heavily depends on hydro-meteorological data. Some of the errors, manual or machine, might exist in the stream flow observation that we collect from different organizations. The main objective of this study was to identify the implications of hydro-meteorological data quality on water resources planning in Weito Watershed. Hydrological and meteorological data of 1985-2011 were collected from MoWIE and NMA. Grubbs T-test was used for identifying outliers in the observed data. In addition, F and t-test for stability of variance and mean were carried out, respectively. Estimation of D-days average minimum flow was also done. Based on 1985-2011 hydro-meteorological data, Grubbs T-value, F-test, and t-test yielded value of 2.86, 0.897 and -0.05, respectively. This indicates, stability of the historical data against mean and variance with no or insignificant outlying values. During the identified dry periods, average minimum flow during 7, 15, and 30 days showed water availability above 5m3/s in the river. The statistical data analysis test and D-days average minimum flow indicated no inflated historical data problem in Weito gauged near bridge. However, the local community did not agree with the results obtained. Therefore, we strictly recommend stake holders, research institutions, and organizations to further verify the quality of these data.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114620621","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":"Evaluation of Surface and Ground Water Quality for Irrigated Agriculture in Ziway Area","authors":"Demelash Wendemeneh, M. Ayana, Partap Singh, A. Haileslassie","doi":"10.59122/134ef80","DOIUrl":"https://doi.org/10.59122/134ef80","url":null,"abstract":"Irrigation water, irrespective of its source, contains a great deal of harmful substances that may reduce crop yield and deteriorate soil quality. The quality of available water sources, in this regard, should be evaluated before using them for irrigation purposes. Therefore, this study was aimed at assessing the quality of irrigation water that farmers used in the area and suggesting possible management options. A total of 24 water samples were collected from 4 extensively used bore holes and 2 abstraction points along the Bulublla River in 2016 and 2017. Fourteen quality parameters were applied following standard laboratory procedures. General linear model of two ways analysis of variance was used to evaluate quality parameters across the locations and water sources. The results revealed that about 64.3% of the parameters showed remarkable variation at P<0.05 across water sources while 35.7% showed variation across locations. Moreover, about 93% of the quality parameters showed higher values in groundwater samples compared to surface water. This suggests that the quality of groundwater would be an issue in the area. Sodium adsorption ratios in all locations were found within acceptable limits for irrigation, but its highest value was observed in groundwater samples. Other secondary water quality indices had also remained very high in ground water samples. Thus, paying attention to thequality of groundwater was very important to maintain soil productivity. In general, all crops could be grown effectively with the assessed water sources. However, management practices such as; fallowing, conjunctive use of both sources and choice of salt tolerant crops might help to maximize yield if crops were irrigated with groundwater.","PeriodicalId":156282,"journal":{"name":"Ethiopian Journal of Water Science and Technology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115139043","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}