Optimizing supplemental irrigation: Tradeoffs between profitability and sustainability

Water production functions are used to model yield response to various levels of supplemental irrigation (SI), to assess water productivity coefficients, and to identify optimum irrigation under various input-output price scenarios. The SI production function is taken as the difference between the total water production function (irrigation + rain) and that of rainwater. Theoretical analysis of the unconstrained objective function shows that the seasonal depth of SI to maximize profit occurs when the marginal product of water equals the ratio of unit water cost to unit product sale price. Applying this analysis to wheat in northern Syria, the production functions of SI under different rainfall conditions are developed. Coupled with current and projected water costs and wheat sale prices, the functions are used to develop an easy-to-use chart for determining seasonal irrigation rates to maximize profit under a range of seasonal rainfall amounts.Results show that, for a given seasonal rainfall, there is a critical value for the ratio of irrigation cost to production price beyond which SI becomes less profitable than rainfed production. Higher product prices and lower irrigation costs encourage the use of more water. Policies supporting high wheat prices and low irrigation costs encourage maximizing yields but with low water productivity. The resulting farmer practice threatens the sustainability of water resources. Balancing profitability versus sustainability is a challenge for policy makers. Our analysis can help national and local water authorities and policy makers determine appropriate policies for water valuation and allocation; and assist extension services and farmers in planning irrigation infrastructure and farm water management.     

Water productivity in smallholder irrigation schemes in South Africa

This study investigates the productivity and value of water in two smallholder irrigation schemes (Zanyokwe and Thabina) in South Africa. We apply the residual valuation method (RVM), willingness to pay (WTP) and cost-based approaches (CBA) (i.e. accounting costs of operation and maintenance) to evaluate water productivity and values per crop, per farm, and by scheme. In both schemes, water value estimated by the RVM for vegetables (cabbage, tomatoes and butternuts) is greater than water value for dry maize. At the farm and scheme levels, a comparison was made between gross margin per m³ of water, WTP per m³ and accounting cost per m³ to estimate the relative value of water productivity. The active farmers in the Zanyokwe scheme have lower WTP per m³ (R0.03) than the gross margin of output (R0.69). Also, the accounting cost (R0.084) per m³ of water is less than the gross margin. In the Thabina scheme, active farmers are willing to pay (R0.19) per m³ of water. Hence farmers in Thabina are ready to pay as much as three times the proposed costs of O&M (R0.062) per m³ of water used. Both the accounting cost and willingness to pay are less than the gross margin per m³ of water in the Zanyokwe scheme. Our findings indicate that extension and training may be required to improve the productive use of water for those farmers whose returns are insufficient to cover the cost of supply.     

Evaluating drip irrigation in commercial tea production in Tanzania

This paper evaluates the performance of the first drip irrigation scheme in commercial tea production in Tanzania with a view to making recommendations for improved management and providing data for investment decisions. Uniformity, efficiency and adequacy of irrigation were calculated and the scheduling of irrigation water was reviewed. Operators were interviewed to highlight the main benefits and problems of the system. Investment and recurrent costs of drip and overhead sprinkler systems were quantified and compared. Root development was assessed qualitatively using excavation pits. Irrigation uniformity DU and efficiency ranged between 88 and 95% in the 10 out of 14 irrigation blocks where endline pressures were at least 0.5 bars, and between 77 and 89% in the four blocks were endline pressure was less than 0.5 bars. Scheduling drip irrigation using tensiometers offered potential water savings of 26% in comparison to a water balance schedule, but these are not currently realised. Gross marginal income was very sensitive to tea price and yield. Economically optimal fertilizer rates vary in dependence of tea price and yield and appear to be lower than the current level of 300 kg N ha⁻¹. The higher costs under drip, compared to overhead sprinklers, were mainly for purchase and installation and fertilizer. The costs of labour for applying water and fertilizer were reduced by nearly 50%. At average 2002 tea prices of 1.31 US$ kg⁻¹, drip irrigation would improve the grower’s gross margin if an additional yield of at least 411 kg ha⁻¹ was achieved. The main threats to drip system performance are discussed. Future research efforts should aim at establishing the yield response of tea to water and fertilizer under drip irrigation.     

An evaluation of the performance of six smallholder irrigation schemes in Zimbabwe

Informal and formal survey procedures were used to assess the performance of six smallholder irrigation schemes. The predominant crops grown at the schemes were maize (Zea mays) in summer and beans (Phaseolus vulgaris) in winter. Average crop yields range from 2.7 to 7.4 t/ha for maize and 0.4 to 2.4 t/ha for beans at the lowest and highest yielding schemes respectively. There was also a large gap between the lower and higher producing farmers at each scheme. Only one out of the six schemes realized a profit margin of more than ZWD 223 per month per plotholder (the minimum wage rate for agriculture workers) after operating and maintenance costs (currently met by government) were deducted. Major constraints on the schemes included limited cash for input purchases, unreliable water supplies for winter cropping, limited market outlets and poor roads. Ways of alleviating some of these constraints to improve overall scheme performance are proposed.     

Analysis of water application costs with a centre pivot system for irrigation of crops in Spain

The aim of this study was to present a methodology to analyse the main factors that influence annual water application costs in centre pivot irrigation systems and to determine the most cost-effective centre pivot design, given the variables of machine length, lateral pipe diameter, sprinkler type (LEPA and fixed and rotating spray plate sprinklers (FSPS and RSPS)), system capacity, application efficiency, and water and energy costs for the irrigation of crops such as maize under conditions in Spain. Annual water application costs were calculated as the sum of the investment (Ca), energy (Ce), water (Cw), and equipment maintenance costs (Cm). Parameters used to assess the influences on pivot design were system capacity S _c = 1.25 L s^?1 ha^?1; application efficiency Ea = 80% for FSPS, Ea = 85% for RSPS, and Ea = 90% for LEPA; water price P _w = 0.06 € m^?3 (0.081 US dollars); energy price En_e = 0.10 € kWh^?1 (0.135 US dollars); net annual crop irrigation water requirement N _n = 7,000 m³ ha^?1 year^?1; and net daily peak crop water requirement N _nmax = 7.63 mm d^?1 for maize. Results indicate that for plots smaller than 30 ha, the recommended pipeline diameter is 127.0 mm (5 in); for 30–40 ha, 168.3 mm (6 5/8 in); for 40–75 ha, 219.1 mm (8 5/8 in); and for 75–100 ha, 254.0 mm (10 in). A multidiameter pipe solution only slightly reduced water application costs in most cases studied. It was also determined that water costs and irrigation efficiency have a major influence on the total annual cost of water application; however, system capacity and energy price did not strongly affect total cost. For this reason, water application uniformity is very important and can be accomplished using a proper nozzle package and regular maintenance. The paper helps farmers determine the most cost-effective centre pivot design and management.     

Operation and maintenance in Asian irrigation: Reappraising government and farmer responsibilities and rights

A major policy concern in irrigation development is reducing government costs of both construction and operation and maintenance. There is increasing interest in shifting some of these costs to the farmers using the irrigation facilities. This paper discusses the opportunities for reducing certain direct costs to government by collaborative arrangements with water users so that the latter mobilize more of their own resources to implement specified O&M activities. Five propositions are discussed which suggest the prerequisites for successful collaboration: (1) reexamining the processes of design and construction now being used, (2) reorienting the policies and procedures of the irrigation agency, (3) increasing farmer involvement in operations, (4) increasing local organizational capacity, and (5) creating new financial procedures.     

Modeling farm-level adoption of deficit irrigation using Positive Mathematical Programming

Irrigated agriculture in the European Union (EU) is currently adapting to new conditions including the principle of the full recovery of water service costs, the reduction of water availability and the increasing variability in the prices of agricultural products. This has fostered an increasing number of economic analyses to investigate farmers’ behaviour by means of mathematical programming techniques including Positive Mathematical Programming (PMP) models.However PMP models generally consider only activities observed in the reference period even if, under new policies and market conditions, farmers can adopt irrigation techniques they have not used previously. In particular, under increasing water costs or decreasing water availability, farmers can introduce Deficit Irrigation (DI) techniques that might not have been profitable earlier.We propose an extension of the PMP approach to include DI techniques not observed in the reference period. These alternative techniques are identified by means of a crop growth model developed by the FAO. We apply our methodology to a Mediterranean area using three sets of simulations involving: increases in water costs, reductions in water availability, and changes in the prices of the products obtained from irrigated crops.Lacking observations of alternative irrigation techniques, our approach captures potential technology adjustments and assesses the impact of changes in water policy and market conditions in a better way.Simulation results show that increasing water costs do not motivate adoption of DI techniques. Rather, farmers are induced to save water by switching from full irrigation to deficit irrigation when water availability is reduced or the prices of irrigated crops are increased.     

玛纳斯河灌区农户农业灌溉水价承受能力研究

从玛纳斯河灌区农户种植棉花平均生产成本和收入情况、水费占成本、收入的比例情况、农户可接受的灌溉水费占单位面积投入比例、农户对现行灌溉水价的评价及对水价构成的认识等方面进行了抽样调查.在此基础上对灌区农户灌溉水价的承受能力进行了分析,给出了该灌区农户水费承受能力指标及2006年该灌区农户可承受的平均终端灌溉水价为0.110 9元/m 3 .为该灌区制定农业灌溉水价改革政策、提高农业水资源利用效率等提供基础资料.     

The financial viability of irrigation management companies: A case study of Cu Chi irrigation system,Vietnam

A crucial, yet little understood, element in the economic studies of irrigation is the role played by companies who manage the supply of water. Many of these companies are publicly managed as they have the potential to act as monopolists. Possibly as a consequence of their ownership structure, analysts have questioned the economic viability and management of these firms. The case is made that many of these companies do not run profitably, that they rely on government subsidies to survive, that they do not spend enough on maintenance and that they run down their capital base. The purpose in this paper is to specify the measures that allow analysts to examine the financial viability of a publicly owned irrigation management companies and to apply these to a scheme in Vietnam. Of concern and contention in any irrigation scheme is the price that a company should charge for water in order to recover costs in the short-run. It was found that the company under investigation could not operate without subsidies and did run down their assets. It was found that a great disparity exists between what the consumers were charged for water and what the company received for supplying it. To ensure the sustainability of the Irrigation Management Companies in long term, they may have to increase the water fee by 3.75 times the current rate set by the provincial government (US$ 20 per ha).     

On-farm labour allocation and irrigation water use: case studies among smallholder systems in arid regions

On-farm measurements and observations of water flow, water costs and irrigation labour inputs at the individual parcel level were made in case studies of smallholder irrigation systems in sub-Saharan Africa and south-eastern Arabia. The systems, in which the water source supplied either single or multiple users, were analysed to address the fundamental issues of labour allocation for on-farm water management as this has important consequences for the success of such systems. Results show that the costs associated with accessing water influenced labour input, because when they were low the farmers tended to increase the irrigation rate and reduce the amount of time they spent distributing the water within their parcels. Conversely when water costs were high, lower flow rates and more time spent in water distribution were observed, and this resulted in more uniform irrigation and higher irrigation efficiency. Also, opportunities and demands for farmers to use their labour for activities other than irrigation can lead them to modify operational or physical aspects of the system so that they can reduce the time they spend distributing water within the parcels, particularly when the water is relatively cheap. Awareness and better understanding of how farmers may allocate their labour for water management will lead to more effective planning, design and management of smallholder irrigation systems.     

Evaluating irrigation performance in a Mediterranean environment

Assessment of irrigation performance is a prerequisite for improving water use in the agricultural sector to respond to perceived water scarcity. Between 1996 and 2000, we conducted a comprehensive assessment of the performance of the Genil–Cabra irrigation scheme (GCIS) located in Andalusia, southern Spain. The area has about 7,000 ha of irrigated lands distributed in 843 parcels and devoted to a diverse crop mix, with cereals, sunflower, cotton, garlic and olive trees as principal crops. Irrigation is on demand from a pressurized system and hand-moved sprinkler irrigation is the most popular application method. Six performance indicators were used to assess the physical and economic performance of irrigation water use and management in the GCIS, using parcel water-use records and a simulation model. The model simulates the water-balance processes on every field and computes an optimal irrigation schedule, which is then checked against actual schedules. Among the performance indicators, the average irrigation water supply:demand ratio (the ratio of measured irrigation supply to the simulated optimum demand) varied among years from 0.45 to 0.64, indicating that the area is under deficit irrigation. When rainfall was included, the supply:demand ratio increased up to 0.87 in one year, although it was only 0.72 in the driest year, showing that farmers did not fully compensate for the low rainfall with sufficient irrigation water. Nevertheless, farmers in the area made an efficient use of rainfall, as indicated by the relatively high values (0.72–0.83) for the ratio of actual:attainable crop yields. Water productivity (WP) in the GCIS oscillated between 0.72 €/m³ and 1.99 €/m³ during the 4 years and averaged 1.42 €/m³ of water supplied for irrigation, while the irrigation water productivity (IWP) averaged 0.63 €/m³ for the period studied. WP is higher than IWP because WP includes production generated by rainfall, while IWP includes only the production generated by irrigation.Communicated by A. Kassam     

Canal irrigation at night

Most canal irrigation water in South and Southeast Asia and elsewhere continues to flow at night and much is badly used or wasted. Yet what happens to water at night is a neglected subject, a matter for anecdotes more than analysis. Darkness, cold, fear, normal working hours, and desire for sleep deter irrigation staff, farmers and labourers from activities at night. At the farm level, irrigation at night entails extra labour and costs. It requires smaller streamflows and well shaped fields. Paddy and trees are the easiest crops to irrigate, and younger, lower and more thinly spread crops are usually easier than those which are older, taller and denser. On the lower parts of main systems, control at night often passes informally from irrigation staff to irrigators. Potential productivity of water at night is slightly raised by lower evaporation losses, but this gain is negligible compared with losses from breaks in channels, inefficient water application, and wasted water flowing into drains. Reuse of night drainage water lower down sometimes makes waste less wasteful than it appears. Equity effects at night are mixed: some farmers poach at the expense of others, but some get water at night who are denied it during the day. Night irrigation increases costs and inconvenience to small farmers, but raises labourers' incomes. Flooding and waterlogging can result from uncontrolled water flows at night.Practical implications are of two types: a)reducing irrigation at night, especially where water can be saved and stored by regulating releases from main reservoirs; in storage or by travelling in canals; by use of intermediate reservoirs; by pondage on-farm; or as groundwater. Care is needed in analysing what is waste and what is water saved. b)improving irrigation at night — by making flows predictable and manageable; by improving convenience and efficiency including lighting, ease of movement and field shaping; by choosing easy crops; by zoning for night flows; and by phasing for short nights, warmth and visibility. The potential for better performance on canal irrigation systems is probably large. It is hoped that this paper will encourage and provoke system managers, designers and researchers to explore the practical potential of this neglected subject about which much more needs to be known. Canal irrigation at night is too important to remain a blind spot any longer.B.C. Punmia & Pande Brij Basi Lal,Irrigation and Water Power Engineering, 7th ed., 1983, p. 48The magnitude of waste involved in not irrigating at night is so huge that savings from other sophistications in the field of water management like the lining of watercourses etc. pale into insignificance.S.P. Malhotra, 1983.Night irrigation and what we know about it is truly a blank page in our books.Gabriel J. Tibor, 1985.     

Farmers’ incentives to save water with new irrigation systems and water taxation—A case study of Serbian potato production

Drip irrigation systems and irrigation strategies like deficit irrigation (DI) and partial root drying (PRD) are potential water saving irrigation systems and strategies. This paper analyses the Serbian farmer's economic incentive to use these water saving systems and strategies instead of the present sprinkler irrigation. The analysis is a partial budgeting analysis, based on irrigation application efficiency from the literature, standard figures for power requirements, pumping efficiency and friction losses for various sources of water and pressure requirements, yields and water use from recent Serbian field experiments, as well as prices and cost structures for potatoes collected in the Belgrade region. The analysis shows that changing the present system and strategy can save a significant amount of water (almost 50%). At the same time, however, irrigation costs are also significantly increased (more than doubled), and the total production costs are increased by 10% (deficit drip irrigation) and 23% (PRD). Increased taxes on water, investment subsidies, increased energy prices, and an increased yield or yield quality may provide incentives for farmers to change to new systems and strategies. The analysis indicates that a 0.80 to 1.97 € m⁻³ water tax is needed to make deficit drip irrigation and PRD profitable. The socioeconomic cost of providing water for irrigation and the alternative value of saved water are probably not that high. Thus, water taxation may not be a socioeconomic efficient means to improve the irrigation water productivity of Serbian potato production. Drip irrigation and PRD may, however, also increase the yield quality, and a 10-23% quality premium (price increase) is needed to make deficit drip irrigation and PRD profitable.     

A study on construction costs per unit area of irrigation projects

The cost constructing for irrigation is often given in $/ha. In deciding whether a project is worth undertaking, it is important to weigh the anticipated benefits against the expected costs. In this study, unit area construction costs based on the way of project water supply (gravity, pump) and scheme type (classic canal, flume, pipe) were calculated for the 211 irrigation projects operated and constructed by DSI (State Hydraulic Works) in Turkey. In a case study of the 27 irrigation schemes constructed by DSI in the Büyük Menderes and West Mediterranean basins, construction costs per unit area, irrigation ratio, and amount of unproductive costs were determined. As a result, though the area of 76383 ha was constructed for irrigation schemes, this area wasn??t under irrigation services with several various reasons; therefore, 641 million $US according to water supply way, and 574 million $US to the scheme type were unproductive investment for irrigation projects researched in the basins.     

Management model for decision support when applying low quality water in irrigation

Use of low quality water for irrigation of food crops is an important option to secure crop productivity in dry regions, alleviate water scarcity and recycle nutrients, but it requires assessment of adverse effects on health and environment. In the EU-project “SAFIR¹” a model system was developed that combines irrigation management with risk evaluation, building on research findings from the different research groups in the SAFIR project. The system applies to field scale irrigation management and aims at assisting users in identifying safe modes of irrigation when applying low quality water. The cornerstone in the model system is the deterministic “Plant-Soil-Atmosphere” model DAISY, which simulates crop growth, water and nitrogen dynamics and if required heavy metals and pathogen fate in the soil. The irrigation and fertigation module calculates irrigation and fertigation requirements based on DAISY's water and nitrogen demands. A Water Source Administration module keeps track of water sources available and their water quality, as well as water treatments, storage, and criteria for selection between different sources. At harvest, the soil concentrations of heavy metals and pathogens are evaluated and the risk to consumers and farmers assessed. Crop profits are calculated, considering fixed and variable costs of input and output. The user can run multiple “what-if” scenarios that include access to different water sources (including wastewater), water treatments, irrigation methods and irrigation and fertilization strategies and evaluate model results in terms of crop yield, water use, fertilizer use, heavy metal accumulation, pathogen exposure and expected profit. The management model system can be used for analysis prior to investments or when preparing a strategy for the season.     

Irrigation water rates in Mendoza's decentralized irrigation administration

The cost of irrigation water to the farmers in Mendoza Province consists of three components; canal cleaning by the farmer, a water charge to their Users Association (UA) and a water charge to the provincial Irrigation Department (DGI). The total cost of irrigation water shows large differences when the area of the UA is taken into consideration: farmers in smaller associations pay considerably more than those in large units. This is the case for all three groups of costs. The annual budgets of 31 UA's were analyzed with respect to 19 budget items prescribed by DGI. Several of these items contain a low percentage of the total budget. Further, they make participation of users during the annual meeting in which the budget is discussed and approved unnecessary difficult. We recommend to reduce the number of budget items to 7. Because of low collection levels (average 64%) the UA's spend a major part of their income on recurrent costs like salaries. As a result little is spent on maintenance and improvement of the system, creating dissatisfaction with the paying water users. Thus. a vicious circle needs to be broken about the deterioration of the system, dissatisfaction of users, less participation in the running of the Association and further deterioration. Recent experience shows that the discontinuation of flow to non-paying users in combination with improved water delivery services by the UA breaks the circle.     

Analysis of water application cost with permanent set sprinkler irrigation systems

In order to identify the subunit design incurring the lowest costs, it is necessary to consider various factors, thereby assuring the correct hydraulic performance of the subunit. Water application costs with a sprinkler irrigation system comprise: investment cost (pumps plant, pipes, sprinklers, ditches), energy, manpower, maintenance and water costs. This work analyses the influence of different design and performance factors, such as subunit arrangement, spacing, working pressure, average application rate, and application efficiency on water application costs in a permanent set sprinkler irrigation subunit. The results show that the most important factor is the spacing between sprinklers. The next most important factor is the shape of the subunit (number of laterals and number of sprinklers per lateral). Working pressure is important too, since a decrease in pressure will result in a decrease in energy costs, although pipe diameter will need to increase. The higher the average application rate of the system, the higher the water application cost. The influence of irrigation efficiency is higher as water price increases. The water application cost can be reduced by 40% when application efficiency increases from 60% to 90%.Communicated by A. Kassam     

MOPECO: an economic optimization model for irrigation water management

Water is a natural, sometimes scarce, and fundamental resource for life, essential both for agriculture in many regions of the world and also to achieve sustainability in production systems. Maximizing net returns with the available resources is of the utmost importance, but doing so is a complex problem, owing to the many factors that affect this process (e.g. climatic variability, irrigation system configuration, production costs, subsidy policies). The MOPECO model is a tool for identifying optimal production plans, and water irrigation management strategies. The model estimates crop yield, production and gross margin as a function of the irrigation depth. Finally, these gross margin functions are used to determine an optimum cropping pattern and irrigation strategy to maximize the gross margin on a farm in a specific scenario. Since the relationships between the variables are generally non-linear and the number of alternative strategies is quite large, the optimum process is complex and computationally intensive. Genetic algorithms are therefore used to identify optimal strategies. This paper describes the MOPECO model, which comprises three computing modules: (1) estimation of net water requirements; (2) derivation of the relationship between gross margin and irrigation depth; and (3) identification of the crop planning and the water volumes to be applied. The results obtained by applying the MOPECO model to a specific irrigable area in a semi-arid area of Spain, with great deficits and high water costs, are also included and discussed. These results usually show that the irrigation depth for maximum benefits is lower than that necessary to obtain maximum production. In some areas of Spain, horticultural crops are nearly always part of the optimum alternative. The crops that become part of the optimum alternative are mainly horticultural crops with a high gross margin and low water requirements. The irrigation depths selected for the ideal crop rotation are included among the irrigation depth of maximum economic efficiency and the maximum gross margin irrigation depth. Both are lower than that necessary for the maximum yield. This model helps farmers, extension services, and other agents to analyse, make decisions and optimize water management.Communicated by A. Kassam     

Pricing of irrigation water under alternative charging methods: Possible shortcomings of a volumetric approach

The European water framework directive aims to protect the environmental quality of water and encourage its efficient use. EU member states are required to implement efficient water management systems and appropriate water-pricing methods. This paper examines the economic effects that may arise given the introduction of two different methods for pricing irrigation in the Mediterranean area. The considered pricing methods charge farmers for the costs incurred by water user associations (WUAs) in managing water distribution networks. The first method, based on the metered use of water by farms, is known as the volumetric pricing method. The second is an area-based pricing method, whereby fees are charged per hectare according to the estimated average water use for each crop. The economic effects and the impacts on the water usage of these two schemes are analyzed using a mathematical model that represents the farm sector in a Mediterranean area that relies on a dam for irrigation. The possible effects are analyzed under two scenarios: first, the methods are applied to the observed water-pricing conditions, second, an additional charge is introduced to recover unaccounted costs of the water supply system (e.g., long-term costs related to infrastructure, and the operational and maintenance costs of dams) in line with the water framework directive principle of cost recovery. The results show that the introduction of an additional charge via the volumetric pricing method could stimulate the substitution of water provided via collective networks with groundwater. This could adversely affect the financial situation of the WUA and have negative environmental consequences. This negative outcome does not arise in the case that an additional charge is applied via the area-based pricing method.     

On-farm performance evaluation of improved traditional small-scale irrigation practices: A case study from Dire Dawa area, Ethiopia

Field evaluation of surface irrigation systems play a fundamental role to determine the efficiency of the system as it is being used and to identify management practices and system configurations that can be implemented to improve the irrigation efficiency. This study evaluated the performance of an ‘improved’ traditional small-scale irrigation practice at Adada, a representative small-scale irrigation practice in Dire Dawa Administrative Council, Eastern Ethiopia. In order to determine numerical values of performance measures, certain parameters were measured/observed before, during and after an irrigation event while farmers are performing their normal irrigation practice. These parameters include: irrigated crop, irrigation method, stream size, cutoff time, soil moisture deficiency, and field size, shape and spacing. The results showed that the irrigation water applied to a farmer's plot during an irrigation event/turn was generally higher than the required depth to be applied per event. Since the irrigation method used was end-dyked, the major cause of water loss was due to deep percolation. The deep percolation loss was 32% in sorghum, 57% in maize, and 70% in tomato and potato fields. The type of irrigation system used, the ridged irrigation practice and the poor irrigation scheduling in the study sites were the main problems identified in the management and operations of the schemes. The following corrective measures are recommended to improve the system: (1) farmers should regulate the depth of irrigation water they apply according to the type of crop and its growth stage, change the field irrigation system and/or configuration especially for shallow rooted row crops, to furrow system, (2) guidance and support to farmers in developing and introduction of appropriate irrigation scheduling, and (3) future development interventions towards improvement of traditional irrigation practices should also focus in improving the on farm irrigation systems in addition to improving physical infrastructure of the scheme.