This research investigates the fair and efficient distribution of water among irrigators, focusin... more This research investigates the fair and efficient distribution of water among irrigators, focusing on the timely and uniform delivery of water. To achieve this, the study utilized various methods such as group discussions, critical informant and expert interviews, and field flow measurements. The degree of fairness in the distribution of irrigation water was determined by analyzing the shift in the relative water supply to end users. The effectiveness of irrigation is inversely proportional to the relative irrigation supply, which can be observed in the scheme's water delivery indicators. The study found that while the estimated delivered flow of water in the head, middle, and tail reaches of the canal was 1.21, 0.58, and 0.23 m 3 /s respectively, the required quantity of discharge was only 0.81, 0.31, and 0.15 m 3 /s. This discrepancy resulted in the inadequate, unreliable, and unequal water supply to irrigators. The research revealed that canal operation and maintenance were the main factors limiting the system's capacity. The findings showed that the adequacy, dependability, equality, and efficiency values were 0.8, 0.14, 0.40, and 0.71, respectively, suggesting that improvements are needed to ensure the timely and equitable distribution of water to irrigators.
International journal of water resources and environmental engineering, Nov 30, 2017
Assessment of irrigation performances is very essential while planning and chalking out managemen... more Assessment of irrigation performances is very essential while planning and chalking out management strategies for various irrigation. However, in Ethiopia, especially Tigray, performance evaluation of irrigation schemes is rarely conducted. The performance of Tahtay Tsalit irrigation scheme was not assessed yet and hence, this research was undertaken to assess the hydraulic performance of the irrigation scheme. The study was carried out during the irrigation season from September to November, 2016. The field measurements on canal dimensions, water flow measurements and water surface elevation were undertaken at selected sampling points. Simple descriptive statistics was employed for analysis of the data collected from field measurements and observations. However, hydraulic performance indicators were used to evaluate the performance of this irrigation scheme. Several factors such as flooding, sedimentation, design problems, damage of sluice gates, abstraction of irrigation water by unwanted plants has been identified in this irrigation scheme for mal-functional of different irrigation structures. Hydraulic performance of the irrigation system was evaluated using ten hydraulic performance indicators. There was no problem in irrigation adequacy (0.84 fair), equity (fair), dependability (0.057 good) and efficiency (0.77 fair) of irrigation water in this irrigation scheme. The average water surface elevation ratio, delivery performance ratio, and delivery duration ratio of the main canal during the monitoring period was less than one, greater than 5 and 150%, respectively. The highest sediment accumulation was observed at head and middle reaches of the irrigation scheme than the tail reaches. Generally, in this irrigation scheme there were a number of irrigation structures which had malfunctioned , and now required to be remodeled with sustainable solution to improve the performance of the irrigation scheme. Hence, it has been recommended that capacity building and awareness creation for irrigation water users, water committee, Woreda and Kebelle expertise are the main key factor to bring a change in irrigation water managements.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
African Journal of Agricultural Research, Jan 22, 2015
This experiment was conducted during February to June 2012 in Demonstration farm of Arba Minch Un... more This experiment was conducted during February to June 2012 in Demonstration farm of Arba Minch University located in the central rift valley of Ethiopia. The aim was to investigate the effects of different levels of deficit irrigation imposed at different growth stages of maize (BH-140) crop on its development, grain yield and water use efficiency. AquaCrop model was calibrated and validated using field experimentation data. The crop water requirement of maize for full irrigation application was calculated using CropWat 8.0. The water application levels considered were 100% of crop evapotranspiration (ETc), 75%ETc, 50%ETc and 25%ETc. based on these irrigation levels and four growth stages of maize crop, ten treatments were arranged. These treatments were replicated three times. Data collected during the experiment were: crop biomass, soil moisture content, irrigation depths and final yield. The result showed that the highest yield was found in treatment six, T6 (8842 Kg/ha) which was subjected to water deficit during mid-and maturity-stages; whereas minimum yield of about 5264 kg/ha was obtained under T8 which was irrigated imposed to deficit during the whole growing season except during the initial stage. The highest (2.11 kg/m 3) and lowest (0.93 kg/m 3) water use efficiency was recorded under T8 and T4. Generally, water deficit of 50%ETc during third and fourth growth stages had no significant effect on the grain yield of maize and it is worthwhile to save irrigation water during these growth stages. The model performed well in simulating the growth of aboveground biomass, grain yield, and canopy cover (CC) for most of the treatments but it was less satisfactory in simulating the growth performance of treatments under prolonged water-deficit. The fact that the AquaCrop model is easy to use, requires less input data, and its sufficient degree of simulation accuracy make it a valuable tool for estimating crop productivity under deficit irrigation, and on-farm water management for improving the efficiency of water use in agriculture.
Environmental risk assessment and remediation, 2018
The dry land areas of Ethiopia account for more than 66.6% of total land area, and are substantia... more The dry land areas of Ethiopia account for more than 66.6% of total land area, and are substantial crop producing areas fall within the semi-arid parts. As a result, crops experience moisture stress at any time during their growth stage. The first action to improve agricultural production in the dry land areas is to apply moisture conservation techniques and then use the limited water efficiently for enhancing water productivity. A study was conducted at Holte kebelle of Dirashae district from April 1, 2016-July 31, 2016 to evaluate effects of conventional practice and straw mulch applications on soil moisture conservation and yield of sorghum under rainfed agriculture with six levels of sorghum straw mulch. The experiment was designed as a single factor experiment in randomized complete block design and replicated four times. Soil moisture has been taken for six times of 30 cm interval up to sorghum root depth (90 cm) in 3 weeks interval and analyzed volumetric moisture content. Physical and chemical properties, Field Capacity and Permanent Wilting Point in respective depths were analyzed. The analysis of variance indicated that there was highly significant difference (p ≤ 0.05) for soil moisture contents determined at 0-30 cm, 30-60 cm and 60-90 cm at different sorghum growth stages and straw applied. 2.2 and 3.0 ton/ha straw mulch prolonged the days to harvesting due to more moisture conservation in the soil profile and significant in growth and yield parameters. The maximum volumetric soil moisture content was recorded in 2.2 and 3.0 ton/ha straw mulch, which were between the Field Capacity and Permanent Wilting Point at different growth stages of sorghum however, grain yield was higher in 2.2 t/ha. Based on the experiment therefore, application of 2.2 ton/ha of sorghum straw mulch was found more effective in conserving soil moisture for maximum yield under rain-fed agricultural system better than other treatments.
With climate change prevailing around the world, understanding the changes in long-term annual an... more With climate change prevailing around the world, understanding the changes in long-term annual and seasonal rainfall at local scales is very important in planning for required adaptation measures. This is especially true for areas such as the Awash River basin where there is very high dependence on rain-fed agriculture characterized by frequent droughts and subsequent famines. The aim of the study is to analyze long-term trends of annual and seasonal rainfall in the Awash River Basin, Ethiopia. Monthly rainfall data extracted from Climatic Research Unit (CRU 4.01) dataset for 54 grid points representing the entire basin were aggregated to find the respective areal annual and seasonal rainfall time series for the entire basin and its seven sub-basins. The Mann-Kendall (MK) test and Sen Slope estimator were applied to the time series for detecting the trends and for estimating the rate of change, respectively. The Statistical software package R version 3.5.2 was used for data extraction, data analyses, and plotting. Geographic information system (GIS) package was also used for grid making, site selection, and mapping. The results showed that no significant trend (at α = 0.05) was identified in annual rainfall in all sub-basins and over the entire basin in the period (1902 to 2016). However, the results for seasonal rainfall are mixed across the study areas. The summer rainfall (June through September) showed significant decreasing trend (at α ≤ 0.1) over five of the seven sub-basins at a rate varying from 4 to 7.4 mm per decade but it showed no trend over the two sub-basins. The autumn rainfall (October through January) showed no significant trends over four of the seven sub-basins but showed increasing trends over three sub-basins at a rate varying from 2 to 5 mm per decade. The winter rainfall (February through May) showed no significant trends over four sub-basins but showed significant increasing trends (at α ≤ 0.1) over three sub-basins at a rate varying from 0.6 to 2.7 mm per decade. At the basin level, the summer rainfall showed a significant decreasing trend (at α = 0.05) while the autumn and winter rainfall showed no significant trends. In addition, shift in some amount of summer rainfall to winter and autumn season was noticed. It is evident that climate change has shown pronounced effects on the trends and patterns of seasonal rainfall. Thus, the study contribute to better understanding of climate change in the basin and the information from the study can be used in planning for adaptation measures against a changing climate.
Journal of Engineering and Applied Science, Feb 13, 2022
Wonji Shoa Sugar Estate (WSSE) is one of the large-scale irrigation schemes in Ethiopia which was... more Wonji Shoa Sugar Estate (WSSE) is one of the large-scale irrigation schemes in Ethiopia which was established in 1951. The aim of this study was to evaluate the performance of current furrow irrigation water management practices of WSSE. Performance evaluation of the current furrow irrigation was evaluated based on field experiment and the WinSRFR model. For this purpose, ten fields were selected from commonly used furrow lengths (32, 48, and 64 m). Application efficiency, distribution uniformity, and deep percolation performance indicators were used for evaluation. The performance of furrow irrigation showed poor performance, and as an improvement option, inflow rate and cutoff time were altered keeping furrow geometry constant. Advance and recession times for all furrow lengths were recorded and simulated using the WinSRFR model to obtain an accurate cutoff time of irrigation. The result obtained showed that the time allocated for all furrow lengths was not accurately determined. As an improvement option, both inflow rate and cutoff time changed and the performance of furrow irrigation significantly improved. By changing those decision variables, application efficacy and deep percolation performance indicators were significantly improved but distribution uniformity was not changed. In almost all statistical indices used, predicted performances by model were better than computed values in the existing situation. From the current result, it can be concluded that the inflow rate and cutoff time should be changed to attain good performance and increase furrow irrigation efficiency. Highlights Performance of current furrow irrigation under Wonji Shoa sugar Estate was evaluated. For the evaluation purposes, different performance indicators were used from the measured data and the result was simulated using WinSRFR model. The performance of existing furrow irrigation practices was showed poor performances Based on the result obtained from the existing furrow irrigation performance, the improvement options were proposed and evaluated.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
African Journal of Agricultural Research, Jan 18, 2011
Deficit irrigation is becoming an important strategy to reduce agricultural water use in arid and... more Deficit irrigation is becoming an important strategy to reduce agricultural water use in arid and semiarid regions. A field experiment was conducted in 2007 to examine the effect of deficit irrigation on the yield performance of maize crop under Arba Minch (Ethiopia) condition. Based on four phonological growth stages (establishment, vegetative, flowering and grain-filling stages) of maize, the crop was subjected to water deficit during one, two or three growth stages. The highest yield obtained was 5.933 tons/ha and the lowest was 3.467 tons/ha. Treatments that were water stressed during single growth stages such as first and second as well as consecutively during two stages, that is, first and second growth stages produced yields that are not significantly different from the yield achieved under fully irrigated treatment. Compared to the maximum yield, 29 to 42% lower yields were registered under treatments that were subjected to water deficit during three growth stages. Not only frequency of water deficit periods but also its timing was found to have effect on the final yield. Treatments which were stressed during two growth stages had 2.2 (0011) to 38.5% (1010) yield reduction compared to the maximum yield. The highest yield reduction was observed under the treatment which was irrigated only during the fourth growth stage (0001), followed by treatment irrigated during first and third growth stages (1010) and then treatments irrigated only during second stage (0100). This shows that prolonged deficit over three growing stages will have more yield reduction impacts. Plots stressed during third and fourth growth stages were found to produce lower yields indicating the severe effects of water stress during flowering (tasseling and silking) and early grain-filling stages on yield. The comparison of water savings achieved under different treatments that had no significant differences in yield level from full irrigated plot (1111I) ranged from 18.2% (treatments 0111 and 1011) to 36.4% (0011). This indicates that water deficit during first and second growth stages had no significant effect on the grain yield of corn and it is worthwhile to save irrigation water under this condition. The water use efficiency increased with decreasing water supply and increasing yield level. Irrigation water use efficiency increased with decreasing water supply and related yield which may not be desirable from farmers' perspective.
Journal of Irrigation and Drainage Engineering-asce, Nov 1, 2021
Article Information Knowledge of crop evapotranspiration (ETc), the combined process of evaporati... more Article Information Knowledge of crop evapotranspiration (ETc), the combined process of evaporation and plant transpiration, is important in agriculture for scheduling farm operations and designing and managing irrigation and drainage systems. Development of crop coefficient (Kc) can enhance crop evapotranspiration (ETc) estimates in specific crop growth stages. However, locally determined Kc information is not available for many important crops in Ethiopia. This research was, therefore, conducted to determine growth stage specific Kc and crop water use for sorghum (Sorghum bicolor L.) var. Gambella-1107 at the Melkassa Agricultural Research Center which is located in a semi arid climate zone in Ethiopia. Drainage type lysimeter was used to measure Gambella-1107 crop water use under water balance system on a clay loam soil and local weather data were used to determine the reference evapotranspiration (ETo). Crop coefficient was developed from measured ETc and ETo calculated using weather data. The growth stages of the crop were assessed as the seasonal change of plant height (pH), leaf area (LA) and leaf area index (LAI). The yield obtained was 5.3 t ha-1 and the measured LAI were 0.2, 4.2, 4.9 and 1.6 at the initial, development, midseason and late season stages, respectively. The maximum LAI was achieved when the plants reach their maximum height at mid-season stage with high crop evapotranspiration due to leaf enlargement that increases transpiration. The measured ETc values were 53.8, 138.5, 214.4, and 94.0 mm during the initial, development, midseason and late-season stages, respectively, and the seasonal total value was 500.7 mm. The calculated Kc values for the crop were 0.45, 0.83, 1.18 and 0.78 during the initial, development, mid-season and late-season stages, respectively. These values were greater than those reported in FAO publication for sorghum varieties which could be a result of soil, climate and crop genetic differences. This suggests the need for developing site-specific Kc values for proper irrigation management.
Awash basin is the only basin that operates with the concept of river basin management and irriga... more Awash basin is the only basin that operates with the concept of river basin management and irrigation water pricing in Ethiopia. The effectiveness and impacts of the current irrigation water pricing system in the basin has not been studied yet. Hence, the objective of this research is to evaluate effects of irrigation water pricing on scheme level water productivity in Awash River basin. Based on systematic selection criteria, 29 irrigation water users were selected from middle and upper Awash. Structured questionnaire and discussions have been used to generate the primary data. Scheme specific data such as area cultivated, amount of water diverted each year, water fee, service charge and operation and maintenance cost for primary irrigation canals of each legal water user in the basin for five consecutive production years (2005/06-2009/10) were collected from Awash Basin Authority. SPSS and CROPWAT were used to analyze the information gathered through questionnaires and irrigation water requirement respectively. Water productivity of cotton, sugarcane and onion was computed for total available water (excess rainfall + irrigation), irrigation water and water lost through crop evapotranspiration. The current irrigation water pricing in Awash basin seems to be low and does not encourage individual users in improving water productivity. Hence, it is resulted in low crop water productivity. Therefore, cost of irrigation water in Awash basin should have to be optimized with a well specified and revised pricing objective(s) if it has to influence the water productivity.
Unless attention is given to productivity improvements in food production, feeding the ever-incre... more Unless attention is given to productivity improvements in food production, feeding the ever-increasing population persist to be the challenge for Ethiopia. The hope that irrigation development improves the productivity of agriculture, ensures food security, overcome impacts of rainfall variability and reduces poverty depends largely on how well the schemes are being operated and managed. This paper presents the results of performance assessments made in selected irrigation schemes in Ethiopia. For this purpose indicators that measure the water delivery and supply as well as output performances have been applied under data scarce situation. The conveyance efficiency in the main systems is found to be in the order of 58 - 89%. Generally the scheme level values of water supply performance indicators such as annual relative water supply (ARWS) and annual relative irrigation supply (ARIS) are equal to unity in Wonji irrigation scheme and greater than one in other schemes indicating that the water supplied exceeded the estimated demand. The values of water delivery ratio (WDR) varies between 0.62 (Wonji scheme) and 1.07 (Hare scheme). Scheme level values of water delivery and supply performance indicators revealed that there is no constraint of water availability at the scheme level. Schemes that produce sugar cane have higher outputs per units of water supplied and harvested area. On the contrary, community managed schemes showed low water productivity than that of large scale government agency managed schemes. As it is evidenced from the analysis of 59 irrigation schemes in the Awash river basin, schemes that use pump diversion have the opportunity to better control the water and sedimentation that enters the field. Pricing of irrigation water and the cost incurred in water conveyance were found to have a positive effect on the land and water resources of the irrigation schemes. Currently the direct water use fee is low to influence the demand and efficiency of water use. However, schemes which use pump diversion were found to consume less water and tended to expand land linearly with the increasing amount of diverted water. Low productivity of irrigated agriculture is possibly attributed to poor conditions of the irrigation infrastructure, inadequate management capacity and skills, lack of proper operation and on-farm water management skills and procedures, lack of incentives and hence low motivation to improve performance. Investment on these factors will have potentially significant impact in improving performance
The water users located at the upstream of the irrigation system have more access to water than t... more The water users located at the upstream of the irrigation system have more access to water than those located at the downstream of the system. Moreover, the irrigation activity of tail-enders is seriously affected in both water scarce and water abundant periods due to under and over irrigation respectively. Not only water but also the situation of landholding affects the productivity and income of the farming community. The goal of this study was to assess the spatial variation of irrigation performance and to evaluate its effects in terms of performance of agricultural production (intensification and productivity), income and resources base as well as the environment. Across-system performance assessment study sponsored by International Water Management Institute (IWMI) was done on the basis of simple illustration of the approach followed for the assessment and different levels of water accessibility along the canal reaches. The level of availability of irrigation water or accessibility to the farm is affected by the proximity of the farm to the water source or to the water carrying canals. The study confirmed that as one gets away from both the water source and the canal the accessibility of water becomes less and less, unless proper system for water allocation is in place and practiced. In view of that, six zones can be differentiated based on the condition of water accessibility. These are highly accessible, moderately accessible, less accessible, very less accessible, poorly accessible and water scarce zones. Sometimes the tail-end, which is characterized by water scarce zone, is also found to be affected by water logging. Since, available water and demand for water are not continuously monitored and managed, the situation outlined paves the path for potential conflicts among water users in response to visible livelihood differences. Despite disruption of downstream users from irrigating their field, significant loss of scarce resource by the upstream users have resulted in detectable environmental threat such as water logging, sodicity (10.44meq/l, k (H.C.) 0.00279cm/hr) and salinity problems in the area.
Knowledge of soil infiltration characteristics is required increasingly for the proper design and... more Knowledge of soil infiltration characteristics is required increasingly for the proper design and efficient management of irrigation. Various empirical and physically based infiltration models have been used for several years, but the practical use of many is limited by parameter determination problems, which, in turn, are influenced by factors acting at the surface and within the soil, initial and boundary conditions, etc. In this study, a simplified approach for determining parameters for the Kostiakov equation was tested and validated. The equation's linearized form, using logarithmic transformation and field data collected from five sites, was employed. The results show that cumulative infiltration can be described well using the approach. Its quality is also confirmed by performance indices like R2 and standard error, whose values ranged from 0.985 to 0.999 and 0.020 to 0.005, respectively, suggesting that the simplified approach described is sufficient for practical purpos...
African Journal of Environmental Science and Technology, 2020
Water quality is a highly concerning issue as long as irrigation is planned to be used for crop p... more Water quality is a highly concerning issue as long as irrigation is planned to be used for crop production. Hence, groundwater at Bochessa catchment was assessed to determine the spatiotemporal variability of its quality and to evaluate its suitability for irrigation. For this study, 8 boreholes were selected and sampling was done during the dry and wet seasons between 2015 and 2017. Totally 48 water samples were collected from monitoring boreholes for laboratory analysis. Water samples were analyzed for 13 parameters including major cations and anions. The general linear model of two ways analysis of variance was used to determine the variability of parameters across the seasons and locations. The results revealed that about 46.0 and 16% of the parameters showed significant variation at P<0.05 across seasons and locations, respectively. This suggests temporal variation has a noticeable effect on the quality of groundwater. Almost all quality parameters showed a declining trend during the wet season. This also confirmed that how temporal variation influences groundwater quality in the area. SAR values in all locations were found within the limit and the water is suitable for irrigation. However, its values showed an increasing trend over time suggesting sodicity may challenge irrigation practices. Therefore, management practices such as; irrigation-fallowing, leaching, and choice of crops may help the farmers to maintain soil productivity.
Dear Participants of the symposium and ladies and gentlemen Ladies and Gentlemen: Allow me to wel... more Dear Participants of the symposium and ladies and gentlemen Ladies and Gentlemen: Allow me to welcome you all to the symposium and exhibition titled "Best Practices and Technologies for Agricultural Water Management in Ethiopia", on behalf of the symposium organizing committee and on behalf of International Water Management Institute. Allow me also please to provide a background reason why this symposium is organized and to introduce the program As you all well know, Ethiopia is a country with land area of over 1.1 million km 2 and it is the second most populous country in sub-Saharan Africa (SSA) (and third on the continent of Africa) with estimated population approaching 80 million people. The population growth is estimated at about 2.8% and this then doubles the population almost every quarter of a century. This is a primary challenge that needs to be properly addressed with equivalent economic growth Majority of the population earn their living from agriculture and most of them are poor. The main economy of Ethiopia dependent on Agriculture, which is mainly dependent on rain fed system, under highly variable rainfall conditions, with progressive degrading natural resources base. The wider poverty vicious cycle of Ethiopia takes dimensions of population growth extending agriculture and livestock into less and less favorable land, deforestation to obtain more agricultural land and more energy to meet demand land and water degradation damage to ecosystem, poor productivity, food insecurity increasing poverty poor health, malnutrition inability to invest in maintaining or improving (land, water, labour) productivity further population growth, degradation and deepening poverty. This is a poverty vicious cycle further aggravated by shocks such as war, drought, etc. xvi
Irrigation water, irrespective of its source, contains a great deal of harmful substances that ma... more 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...
This research investigates the fair and efficient distribution of water among irrigators, focusin... more This research investigates the fair and efficient distribution of water among irrigators, focusing on the timely and uniform delivery of water. To achieve this, the study utilized various methods such as group discussions, critical informant and expert interviews, and field flow measurements. The degree of fairness in the distribution of irrigation water was determined by analyzing the shift in the relative water supply to end users. The effectiveness of irrigation is inversely proportional to the relative irrigation supply, which can be observed in the scheme's water delivery indicators. The study found that while the estimated delivered flow of water in the head, middle, and tail reaches of the canal was 1.21, 0.58, and 0.23 m 3 /s respectively, the required quantity of discharge was only 0.81, 0.31, and 0.15 m 3 /s. This discrepancy resulted in the inadequate, unreliable, and unequal water supply to irrigators. The research revealed that canal operation and maintenance were the main factors limiting the system's capacity. The findings showed that the adequacy, dependability, equality, and efficiency values were 0.8, 0.14, 0.40, and 0.71, respectively, suggesting that improvements are needed to ensure the timely and equitable distribution of water to irrigators.
International journal of water resources and environmental engineering, Nov 30, 2017
Assessment of irrigation performances is very essential while planning and chalking out managemen... more Assessment of irrigation performances is very essential while planning and chalking out management strategies for various irrigation. However, in Ethiopia, especially Tigray, performance evaluation of irrigation schemes is rarely conducted. The performance of Tahtay Tsalit irrigation scheme was not assessed yet and hence, this research was undertaken to assess the hydraulic performance of the irrigation scheme. The study was carried out during the irrigation season from September to November, 2016. The field measurements on canal dimensions, water flow measurements and water surface elevation were undertaken at selected sampling points. Simple descriptive statistics was employed for analysis of the data collected from field measurements and observations. However, hydraulic performance indicators were used to evaluate the performance of this irrigation scheme. Several factors such as flooding, sedimentation, design problems, damage of sluice gates, abstraction of irrigation water by unwanted plants has been identified in this irrigation scheme for mal-functional of different irrigation structures. Hydraulic performance of the irrigation system was evaluated using ten hydraulic performance indicators. There was no problem in irrigation adequacy (0.84 fair), equity (fair), dependability (0.057 good) and efficiency (0.77 fair) of irrigation water in this irrigation scheme. The average water surface elevation ratio, delivery performance ratio, and delivery duration ratio of the main canal during the monitoring period was less than one, greater than 5 and 150%, respectively. The highest sediment accumulation was observed at head and middle reaches of the irrigation scheme than the tail reaches. Generally, in this irrigation scheme there were a number of irrigation structures which had malfunctioned , and now required to be remodeled with sustainable solution to improve the performance of the irrigation scheme. Hence, it has been recommended that capacity building and awareness creation for irrigation water users, water committee, Woreda and Kebelle expertise are the main key factor to bring a change in irrigation water managements.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
African Journal of Agricultural Research, Jan 22, 2015
This experiment was conducted during February to June 2012 in Demonstration farm of Arba Minch Un... more This experiment was conducted during February to June 2012 in Demonstration farm of Arba Minch University located in the central rift valley of Ethiopia. The aim was to investigate the effects of different levels of deficit irrigation imposed at different growth stages of maize (BH-140) crop on its development, grain yield and water use efficiency. AquaCrop model was calibrated and validated using field experimentation data. The crop water requirement of maize for full irrigation application was calculated using CropWat 8.0. The water application levels considered were 100% of crop evapotranspiration (ETc), 75%ETc, 50%ETc and 25%ETc. based on these irrigation levels and four growth stages of maize crop, ten treatments were arranged. These treatments were replicated three times. Data collected during the experiment were: crop biomass, soil moisture content, irrigation depths and final yield. The result showed that the highest yield was found in treatment six, T6 (8842 Kg/ha) which was subjected to water deficit during mid-and maturity-stages; whereas minimum yield of about 5264 kg/ha was obtained under T8 which was irrigated imposed to deficit during the whole growing season except during the initial stage. The highest (2.11 kg/m 3) and lowest (0.93 kg/m 3) water use efficiency was recorded under T8 and T4. Generally, water deficit of 50%ETc during third and fourth growth stages had no significant effect on the grain yield of maize and it is worthwhile to save irrigation water during these growth stages. The model performed well in simulating the growth of aboveground biomass, grain yield, and canopy cover (CC) for most of the treatments but it was less satisfactory in simulating the growth performance of treatments under prolonged water-deficit. The fact that the AquaCrop model is easy to use, requires less input data, and its sufficient degree of simulation accuracy make it a valuable tool for estimating crop productivity under deficit irrigation, and on-farm water management for improving the efficiency of water use in agriculture.
Environmental risk assessment and remediation, 2018
The dry land areas of Ethiopia account for more than 66.6% of total land area, and are substantia... more The dry land areas of Ethiopia account for more than 66.6% of total land area, and are substantial crop producing areas fall within the semi-arid parts. As a result, crops experience moisture stress at any time during their growth stage. The first action to improve agricultural production in the dry land areas is to apply moisture conservation techniques and then use the limited water efficiently for enhancing water productivity. A study was conducted at Holte kebelle of Dirashae district from April 1, 2016-July 31, 2016 to evaluate effects of conventional practice and straw mulch applications on soil moisture conservation and yield of sorghum under rainfed agriculture with six levels of sorghum straw mulch. The experiment was designed as a single factor experiment in randomized complete block design and replicated four times. Soil moisture has been taken for six times of 30 cm interval up to sorghum root depth (90 cm) in 3 weeks interval and analyzed volumetric moisture content. Physical and chemical properties, Field Capacity and Permanent Wilting Point in respective depths were analyzed. The analysis of variance indicated that there was highly significant difference (p ≤ 0.05) for soil moisture contents determined at 0-30 cm, 30-60 cm and 60-90 cm at different sorghum growth stages and straw applied. 2.2 and 3.0 ton/ha straw mulch prolonged the days to harvesting due to more moisture conservation in the soil profile and significant in growth and yield parameters. The maximum volumetric soil moisture content was recorded in 2.2 and 3.0 ton/ha straw mulch, which were between the Field Capacity and Permanent Wilting Point at different growth stages of sorghum however, grain yield was higher in 2.2 t/ha. Based on the experiment therefore, application of 2.2 ton/ha of sorghum straw mulch was found more effective in conserving soil moisture for maximum yield under rain-fed agricultural system better than other treatments.
With climate change prevailing around the world, understanding the changes in long-term annual an... more With climate change prevailing around the world, understanding the changes in long-term annual and seasonal rainfall at local scales is very important in planning for required adaptation measures. This is especially true for areas such as the Awash River basin where there is very high dependence on rain-fed agriculture characterized by frequent droughts and subsequent famines. The aim of the study is to analyze long-term trends of annual and seasonal rainfall in the Awash River Basin, Ethiopia. Monthly rainfall data extracted from Climatic Research Unit (CRU 4.01) dataset for 54 grid points representing the entire basin were aggregated to find the respective areal annual and seasonal rainfall time series for the entire basin and its seven sub-basins. The Mann-Kendall (MK) test and Sen Slope estimator were applied to the time series for detecting the trends and for estimating the rate of change, respectively. The Statistical software package R version 3.5.2 was used for data extraction, data analyses, and plotting. Geographic information system (GIS) package was also used for grid making, site selection, and mapping. The results showed that no significant trend (at α = 0.05) was identified in annual rainfall in all sub-basins and over the entire basin in the period (1902 to 2016). However, the results for seasonal rainfall are mixed across the study areas. The summer rainfall (June through September) showed significant decreasing trend (at α ≤ 0.1) over five of the seven sub-basins at a rate varying from 4 to 7.4 mm per decade but it showed no trend over the two sub-basins. The autumn rainfall (October through January) showed no significant trends over four of the seven sub-basins but showed increasing trends over three sub-basins at a rate varying from 2 to 5 mm per decade. The winter rainfall (February through May) showed no significant trends over four sub-basins but showed significant increasing trends (at α ≤ 0.1) over three sub-basins at a rate varying from 0.6 to 2.7 mm per decade. At the basin level, the summer rainfall showed a significant decreasing trend (at α = 0.05) while the autumn and winter rainfall showed no significant trends. In addition, shift in some amount of summer rainfall to winter and autumn season was noticed. It is evident that climate change has shown pronounced effects on the trends and patterns of seasonal rainfall. Thus, the study contribute to better understanding of climate change in the basin and the information from the study can be used in planning for adaptation measures against a changing climate.
Journal of Engineering and Applied Science, Feb 13, 2022
Wonji Shoa Sugar Estate (WSSE) is one of the large-scale irrigation schemes in Ethiopia which was... more Wonji Shoa Sugar Estate (WSSE) is one of the large-scale irrigation schemes in Ethiopia which was established in 1951. The aim of this study was to evaluate the performance of current furrow irrigation water management practices of WSSE. Performance evaluation of the current furrow irrigation was evaluated based on field experiment and the WinSRFR model. For this purpose, ten fields were selected from commonly used furrow lengths (32, 48, and 64 m). Application efficiency, distribution uniformity, and deep percolation performance indicators were used for evaluation. The performance of furrow irrigation showed poor performance, and as an improvement option, inflow rate and cutoff time were altered keeping furrow geometry constant. Advance and recession times for all furrow lengths were recorded and simulated using the WinSRFR model to obtain an accurate cutoff time of irrigation. The result obtained showed that the time allocated for all furrow lengths was not accurately determined. As an improvement option, both inflow rate and cutoff time changed and the performance of furrow irrigation significantly improved. By changing those decision variables, application efficacy and deep percolation performance indicators were significantly improved but distribution uniformity was not changed. In almost all statistical indices used, predicted performances by model were better than computed values in the existing situation. From the current result, it can be concluded that the inflow rate and cutoff time should be changed to attain good performance and increase furrow irrigation efficiency. Highlights Performance of current furrow irrigation under Wonji Shoa sugar Estate was evaluated. For the evaluation purposes, different performance indicators were used from the measured data and the result was simulated using WinSRFR model. The performance of existing furrow irrigation practices was showed poor performances Based on the result obtained from the existing furrow irrigation performance, the improvement options were proposed and evaluated.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
African Journal of Agricultural Research, Jan 18, 2011
Deficit irrigation is becoming an important strategy to reduce agricultural water use in arid and... more Deficit irrigation is becoming an important strategy to reduce agricultural water use in arid and semiarid regions. A field experiment was conducted in 2007 to examine the effect of deficit irrigation on the yield performance of maize crop under Arba Minch (Ethiopia) condition. Based on four phonological growth stages (establishment, vegetative, flowering and grain-filling stages) of maize, the crop was subjected to water deficit during one, two or three growth stages. The highest yield obtained was 5.933 tons/ha and the lowest was 3.467 tons/ha. Treatments that were water stressed during single growth stages such as first and second as well as consecutively during two stages, that is, first and second growth stages produced yields that are not significantly different from the yield achieved under fully irrigated treatment. Compared to the maximum yield, 29 to 42% lower yields were registered under treatments that were subjected to water deficit during three growth stages. Not only frequency of water deficit periods but also its timing was found to have effect on the final yield. Treatments which were stressed during two growth stages had 2.2 (0011) to 38.5% (1010) yield reduction compared to the maximum yield. The highest yield reduction was observed under the treatment which was irrigated only during the fourth growth stage (0001), followed by treatment irrigated during first and third growth stages (1010) and then treatments irrigated only during second stage (0100). This shows that prolonged deficit over three growing stages will have more yield reduction impacts. Plots stressed during third and fourth growth stages were found to produce lower yields indicating the severe effects of water stress during flowering (tasseling and silking) and early grain-filling stages on yield. The comparison of water savings achieved under different treatments that had no significant differences in yield level from full irrigated plot (1111I) ranged from 18.2% (treatments 0111 and 1011) to 36.4% (0011). This indicates that water deficit during first and second growth stages had no significant effect on the grain yield of corn and it is worthwhile to save irrigation water under this condition. The water use efficiency increased with decreasing water supply and increasing yield level. Irrigation water use efficiency increased with decreasing water supply and related yield which may not be desirable from farmers' perspective.
Journal of Irrigation and Drainage Engineering-asce, Nov 1, 2021
Article Information Knowledge of crop evapotranspiration (ETc), the combined process of evaporati... more Article Information Knowledge of crop evapotranspiration (ETc), the combined process of evaporation and plant transpiration, is important in agriculture for scheduling farm operations and designing and managing irrigation and drainage systems. Development of crop coefficient (Kc) can enhance crop evapotranspiration (ETc) estimates in specific crop growth stages. However, locally determined Kc information is not available for many important crops in Ethiopia. This research was, therefore, conducted to determine growth stage specific Kc and crop water use for sorghum (Sorghum bicolor L.) var. Gambella-1107 at the Melkassa Agricultural Research Center which is located in a semi arid climate zone in Ethiopia. Drainage type lysimeter was used to measure Gambella-1107 crop water use under water balance system on a clay loam soil and local weather data were used to determine the reference evapotranspiration (ETo). Crop coefficient was developed from measured ETc and ETo calculated using weather data. The growth stages of the crop were assessed as the seasonal change of plant height (pH), leaf area (LA) and leaf area index (LAI). The yield obtained was 5.3 t ha-1 and the measured LAI were 0.2, 4.2, 4.9 and 1.6 at the initial, development, midseason and late season stages, respectively. The maximum LAI was achieved when the plants reach their maximum height at mid-season stage with high crop evapotranspiration due to leaf enlargement that increases transpiration. The measured ETc values were 53.8, 138.5, 214.4, and 94.0 mm during the initial, development, midseason and late-season stages, respectively, and the seasonal total value was 500.7 mm. The calculated Kc values for the crop were 0.45, 0.83, 1.18 and 0.78 during the initial, development, mid-season and late-season stages, respectively. These values were greater than those reported in FAO publication for sorghum varieties which could be a result of soil, climate and crop genetic differences. This suggests the need for developing site-specific Kc values for proper irrigation management.
Awash basin is the only basin that operates with the concept of river basin management and irriga... more Awash basin is the only basin that operates with the concept of river basin management and irrigation water pricing in Ethiopia. The effectiveness and impacts of the current irrigation water pricing system in the basin has not been studied yet. Hence, the objective of this research is to evaluate effects of irrigation water pricing on scheme level water productivity in Awash River basin. Based on systematic selection criteria, 29 irrigation water users were selected from middle and upper Awash. Structured questionnaire and discussions have been used to generate the primary data. Scheme specific data such as area cultivated, amount of water diverted each year, water fee, service charge and operation and maintenance cost for primary irrigation canals of each legal water user in the basin for five consecutive production years (2005/06-2009/10) were collected from Awash Basin Authority. SPSS and CROPWAT were used to analyze the information gathered through questionnaires and irrigation water requirement respectively. Water productivity of cotton, sugarcane and onion was computed for total available water (excess rainfall + irrigation), irrigation water and water lost through crop evapotranspiration. The current irrigation water pricing in Awash basin seems to be low and does not encourage individual users in improving water productivity. Hence, it is resulted in low crop water productivity. Therefore, cost of irrigation water in Awash basin should have to be optimized with a well specified and revised pricing objective(s) if it has to influence the water productivity.
Unless attention is given to productivity improvements in food production, feeding the ever-incre... more Unless attention is given to productivity improvements in food production, feeding the ever-increasing population persist to be the challenge for Ethiopia. The hope that irrigation development improves the productivity of agriculture, ensures food security, overcome impacts of rainfall variability and reduces poverty depends largely on how well the schemes are being operated and managed. This paper presents the results of performance assessments made in selected irrigation schemes in Ethiopia. For this purpose indicators that measure the water delivery and supply as well as output performances have been applied under data scarce situation. The conveyance efficiency in the main systems is found to be in the order of 58 - 89%. Generally the scheme level values of water supply performance indicators such as annual relative water supply (ARWS) and annual relative irrigation supply (ARIS) are equal to unity in Wonji irrigation scheme and greater than one in other schemes indicating that the water supplied exceeded the estimated demand. The values of water delivery ratio (WDR) varies between 0.62 (Wonji scheme) and 1.07 (Hare scheme). Scheme level values of water delivery and supply performance indicators revealed that there is no constraint of water availability at the scheme level. Schemes that produce sugar cane have higher outputs per units of water supplied and harvested area. On the contrary, community managed schemes showed low water productivity than that of large scale government agency managed schemes. As it is evidenced from the analysis of 59 irrigation schemes in the Awash river basin, schemes that use pump diversion have the opportunity to better control the water and sedimentation that enters the field. Pricing of irrigation water and the cost incurred in water conveyance were found to have a positive effect on the land and water resources of the irrigation schemes. Currently the direct water use fee is low to influence the demand and efficiency of water use. However, schemes which use pump diversion were found to consume less water and tended to expand land linearly with the increasing amount of diverted water. Low productivity of irrigated agriculture is possibly attributed to poor conditions of the irrigation infrastructure, inadequate management capacity and skills, lack of proper operation and on-farm water management skills and procedures, lack of incentives and hence low motivation to improve performance. Investment on these factors will have potentially significant impact in improving performance
The water users located at the upstream of the irrigation system have more access to water than t... more The water users located at the upstream of the irrigation system have more access to water than those located at the downstream of the system. Moreover, the irrigation activity of tail-enders is seriously affected in both water scarce and water abundant periods due to under and over irrigation respectively. Not only water but also the situation of landholding affects the productivity and income of the farming community. The goal of this study was to assess the spatial variation of irrigation performance and to evaluate its effects in terms of performance of agricultural production (intensification and productivity), income and resources base as well as the environment. Across-system performance assessment study sponsored by International Water Management Institute (IWMI) was done on the basis of simple illustration of the approach followed for the assessment and different levels of water accessibility along the canal reaches. The level of availability of irrigation water or accessibility to the farm is affected by the proximity of the farm to the water source or to the water carrying canals. The study confirmed that as one gets away from both the water source and the canal the accessibility of water becomes less and less, unless proper system for water allocation is in place and practiced. In view of that, six zones can be differentiated based on the condition of water accessibility. These are highly accessible, moderately accessible, less accessible, very less accessible, poorly accessible and water scarce zones. Sometimes the tail-end, which is characterized by water scarce zone, is also found to be affected by water logging. Since, available water and demand for water are not continuously monitored and managed, the situation outlined paves the path for potential conflicts among water users in response to visible livelihood differences. Despite disruption of downstream users from irrigating their field, significant loss of scarce resource by the upstream users have resulted in detectable environmental threat such as water logging, sodicity (10.44meq/l, k (H.C.) 0.00279cm/hr) and salinity problems in the area.
Knowledge of soil infiltration characteristics is required increasingly for the proper design and... more Knowledge of soil infiltration characteristics is required increasingly for the proper design and efficient management of irrigation. Various empirical and physically based infiltration models have been used for several years, but the practical use of many is limited by parameter determination problems, which, in turn, are influenced by factors acting at the surface and within the soil, initial and boundary conditions, etc. In this study, a simplified approach for determining parameters for the Kostiakov equation was tested and validated. The equation's linearized form, using logarithmic transformation and field data collected from five sites, was employed. The results show that cumulative infiltration can be described well using the approach. Its quality is also confirmed by performance indices like R2 and standard error, whose values ranged from 0.985 to 0.999 and 0.020 to 0.005, respectively, suggesting that the simplified approach described is sufficient for practical purpos...
African Journal of Environmental Science and Technology, 2020
Water quality is a highly concerning issue as long as irrigation is planned to be used for crop p... more Water quality is a highly concerning issue as long as irrigation is planned to be used for crop production. Hence, groundwater at Bochessa catchment was assessed to determine the spatiotemporal variability of its quality and to evaluate its suitability for irrigation. For this study, 8 boreholes were selected and sampling was done during the dry and wet seasons between 2015 and 2017. Totally 48 water samples were collected from monitoring boreholes for laboratory analysis. Water samples were analyzed for 13 parameters including major cations and anions. The general linear model of two ways analysis of variance was used to determine the variability of parameters across the seasons and locations. The results revealed that about 46.0 and 16% of the parameters showed significant variation at P<0.05 across seasons and locations, respectively. This suggests temporal variation has a noticeable effect on the quality of groundwater. Almost all quality parameters showed a declining trend during the wet season. This also confirmed that how temporal variation influences groundwater quality in the area. SAR values in all locations were found within the limit and the water is suitable for irrigation. However, its values showed an increasing trend over time suggesting sodicity may challenge irrigation practices. Therefore, management practices such as; irrigation-fallowing, leaching, and choice of crops may help the farmers to maintain soil productivity.
Dear Participants of the symposium and ladies and gentlemen Ladies and Gentlemen: Allow me to wel... more Dear Participants of the symposium and ladies and gentlemen Ladies and Gentlemen: Allow me to welcome you all to the symposium and exhibition titled "Best Practices and Technologies for Agricultural Water Management in Ethiopia", on behalf of the symposium organizing committee and on behalf of International Water Management Institute. Allow me also please to provide a background reason why this symposium is organized and to introduce the program As you all well know, Ethiopia is a country with land area of over 1.1 million km 2 and it is the second most populous country in sub-Saharan Africa (SSA) (and third on the continent of Africa) with estimated population approaching 80 million people. The population growth is estimated at about 2.8% and this then doubles the population almost every quarter of a century. This is a primary challenge that needs to be properly addressed with equivalent economic growth Majority of the population earn their living from agriculture and most of them are poor. The main economy of Ethiopia dependent on Agriculture, which is mainly dependent on rain fed system, under highly variable rainfall conditions, with progressive degrading natural resources base. The wider poverty vicious cycle of Ethiopia takes dimensions of population growth extending agriculture and livestock into less and less favorable land, deforestation to obtain more agricultural land and more energy to meet demand land and water degradation damage to ecosystem, poor productivity, food insecurity increasing poverty poor health, malnutrition inability to invest in maintaining or improving (land, water, labour) productivity further population growth, degradation and deepening poverty. This is a poverty vicious cycle further aggravated by shocks such as war, drought, etc. xvi
Irrigation water, irrespective of its source, contains a great deal of harmful substances that ma... more 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...
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