A comparative description of two farmer-managed irrigation systems in Nepal

The organization of two farmer-managed irrigation systems in the western hills of Nepal is described by examining the ways in which the activities of water allocation, water distribution, maintenance, and resource mobilization are performed. Due to the topography and environment, these two organizations are structured primarily to mobilize the large amount of labor required for maintenance of the intake and canal. Both organizations precisely define each member's water allocation. In one system, water is allocated in proportion to the area of an individual's land holding, while in the other water allocation is by purchased shares. These two cases were used to analyze the importance of the principle of water allocation for expansion of area irrigated and equity of access to irrigation. Evidence from the two systems shows that in this hill environment water allocation by purchased shares provides the individual incentive and an organizational mechanism for efficient development of irrigation resources. Expansion of area irrigated and equity of access to irrigation were found to be greater in the system which allocates water by purchased shares than where water was allocated in proportion to area irrigated.     

Comparing water management in rice-wheat production systems in Haryana, India and Punjab, Pakistan

The intensive irrigated rice-wheat systems in the northwest Indo-Gangetic Plains of South Asia are built on a long tradition of canal irrigation and the more recent advent of tubewells. Findings from farm surveys are used to examine water management and water productivity in the rice-wheat belt of India's Haryana State and Pakistan's Punjab province. Attributes of the irrigation sources help explain the widespread interest in groundwater use and the relative demise of canal water use. In each area groundwater now is the main irrigation source, used either solely or in conjunction with surface water. The ownership of tubewells is near universal among the surveyed farms, whereas conjunctive water use is more widespread during the monsoon season, among better endowed farmers and in the Pakistan Punjab. In Pakistan Punjab farmers primarily rely on diesel powered tubewells whereas Haryana farmers mainly use relatively cheaper electric power. Water productivity indicators for rice are markedly lower than those for wheat—largely reflecting significantly higher water inputs in paddy cultivation—but also vary between the study areas and by the prevailing water use, reflecting the limited incentives for farmers to use water wisely. A combination of technological, land use and market based approaches is likely to be most effective in achieving sustainable water management in these intensive cereal systems.     

Effects of alternative water distribution rules on irrigation system performance: a simulation analysis

Based on a simulation model reflecting physical and economic conditions typically found in rice irrigation systems in Asia, the irrigation performance implications of alternative water distribution rules for dry season irrigation are evaluated under varying degrees of water shortage. The rules examined reflect differing water distribution strategies designed either to maximize conveyance efficiency, economic efficiency, or equity; or to achieve a balance between efficiency and equity objectives. Irrigation performance is evaluated using several efficiency measures reflecting the physical, agronomic and economic productivity of water, and one measure of equity. Economic efficiency and equity among farmers within the portion of the irrigation system that is on in any given season are shown to be complementary, and not competing objectives. Economic efficiency and equity among all farmers within the command area of the irrigation system are largely complementary strategies at the lower levels of water shortage, but with increasing shortage, significant tradeoffs develop between these objectives. An operational rule for water distribution under a goal of maximizing economic efficiency is developed, and the data requirements for its implementation are shown to be modest. Under the model's assumed conditions of dry season rice production dependent solely on surface irrigation for water, the distribution strategy designed to maximize conveyance efficiency results in only modestly lower levels of economic efficiency and equity than could be achieved by the strategy designed to maximize economic efficiency.     

Efficacy of mulching, irrigation and nitrogen applications on bottle gourd and okra for yield improvement and crop diversification

An on-farm irrigation trial conducted on the upland of Chitwan valley of Nepal evaluated the amount and frequency of irrigation as well as the effect of nitrogen fertilizer and straw mulch applications on the performance of bottle gourd and okra vegetables. The experiment was laid out on split-split-plot design with fertilizer as main-plot factor, frequencies of irrigation as sub-plot factor, and amount of irrigation as sub-sub-plot factor. Data analysis revealed that frequency and amount of irrigation had a significant interaction effect on the number of nodes that emerge before the opening of the first flower in bottle gourd. Likewise, a significant effect of mulching was observed on the number of primary branches (P = 0.05). Number of nodes and primary branches both contributed to higher production of bottle gourd. Results also indicated that frequent application of higher amount of irrigation to bottle gourd could lead to reduced water productivity and suffer from yield losses. In the case of okra, low level of nitrogen application (30 kg N ha⁻¹) with low but daily watering had significantly higher yield (1,365 g plot⁻¹) than from higher level of nitrogen application (90 kg ha⁻¹) (P = 0.01). Interaction effect of all factors was also significant (P = 0.05) on the fruit yield of okra which implied greater value of smaller irrigation to contribute to increased returns to farmers by improving production level of okra in this area of Nepal     

Multiple-Use Management in a Large Irrigation System: Benefits of Distributed Secondary Storage

Large-scale canal irrigation projects are commonly seen as profligate users of water. Their low water productivity has been attributed by many authors to deficiencies in management or to actions by farmers to circumvent management control over water distribution. Inadequate design has sometimes been cited as a contributing factor, but the relationship between design and manageability has received too little attention. In most conventional large-scale irrigation systems imperfect matching between water supply and demand is an inescapable fact of life that leads to operational spillages and low efficiency. Provision of auxiliary storage reservoirs at strategic points within the canal system can buffer this mismatch and improve service delivery and also aid recovery of return flows. Such reservoirs may bring additional benefits in that they provide opportunities for multiple-use management and increased productivity of irrigation water. This paper presents a case study of Mahaweli System H in Sri Lanka, which incorporates a large number of secondary reservoirs within its 25000 ha command area. The paper examines current operational performance and considers scope for and constraints to multiple-use management.     

Farmer's perspective on irrigation performance

Of the many client groups with interests in irrigation system performance, farmers are probably the least often considered. This paper attempts to explore the meaning of irrigation performance from their perspective, highlighting at the outset basic difference between this perspective and that of system managers. It then reviews several important concepts underlying a consideration of performance in irrigation systems. The paper then proposes and discusses a set of twelve measures of irrigation service judged to be of interest to farmers. These are adequacy, timeliness, equity, tractability, convenience, predictability, temperature, sediment content, salt content, nutrient content, toxics, and pathogens.     

建立灌区农民用水者协会的探讨

建立农民用水者协会（ＷＵＡ），国家将支、分渠系灌溉工程的使用与管理权移交给农民，这符合我国政府关于水利工程分级管理的方针政策，对促进灌区工程体制改革，适应社会主义市场经济新要求，实现灌区自我维护，自我发展，经济自立，均具有较大的实践意义。１９９５年４月，湖北省人民政府办公厅３３号文同意在湖北省世行贷款项目区内开展经济自立灌溉区试点工作，并将漳河水库三干渠三分干灌区首批列入试点，在省世行贷款水利项目办公室和荆门市人民政府领导和支持下，通过一年的试点工作实践，先后组建了１１个农民用水者协会，并开始试运行。作者就组建农民用水者协会过程中涉及的有关问题从理论上进行了初步总结。     

Performance assessment of irrigation water management of heterogeneous irrigation schemes: 2. A case study

The non-uniformity of soils, weather, fields, cropping pattern and canal systems in most surface irrigation schemes makes irrigation water management complex, but optimum performance is important particularly in irrigation schemes with limited water supply. This paper focuses on the performance of irrigation water management during the area and water allocation with a case study of an irrigation scheme in the semi-arid region of India. Often the irrigation managers or authorities of these heterogeneous irrigation schemes also need to deal with different allocation rules. The allocation plans and the corresponding water delivery schedules during the allocation process were estimated with the help of a simulation–optimisation model for different allocation rules based on cropping distributions (free and fixed), water distributions (free and fixed-area proportionate), irrigation depth (full, fixed depth and variable depth irrigation) and irrigation interval (from 14 to 35 days). The performance measures of productivity (in terms of net benefits and area irrigated), equity (in water distribution), adequacy and excess were assessed for these different allocation plans and schedules. These were further compared with the performance measures of the existing rule (fixed depth irrigation at a fixed interval). The analysis revealed that these performance measures are in some cases complimentary and in other cases conflicting with each other. Therefore, it would be appropriate for the irrigation managers to understand fully the nature of the variation in performance measures for different allocation rules prior to deciding the allocation plans for the irrigation scheme.     

灌区配水调度模型及其应用

为使灌区的用水管理由经验定性决策向科学定量决策过渡，研制了位山灌区配水调度模型。本模型以干渠测流站为基础，按照“流量包段、责任到所”及“计量供水到县（市区）”的原则，将灌区分设东、西渠系统，干渠分为若干段，段内分片。模型设计紧密联系位山灌区的配水现状，分析研究存在的问题，将常规调水技术抽象概化成不同的配水方式。该配水调度模型从1991年开始使用至今。     

Evaluating planning and delivery performance of Water User Associations (WUAs) in Osh Province, Kyrgyzstan

The primary objective of an irrigation organization is to provide efficient and effective management of water resources to achieve enhanced agricultural production. Performance assessment studies provide a tool to evaluate and promote this objective. The study examines the existing planning procedures and assesses irrigation performance of four Water User Associations (WUAs) located in Osh Province, Kyrgyzstan. Performance was evaluated using indicators of adequacy, efficiency, dependability and equity. Indicators were calculated for each irrigation season over the period 2003 to 2007. In general, all WUAs were found to be strong in terms of adequacy and efficiency standards. However, performance with respect to dependability and equity was poor. The results suggest that more effort is needed to improve temporal uniformity and equity in water distribution. In order to achieve this, estimations of irrigation requirements by WUA managers needs to be improved and mechanisms developed to request water in quantities, which are needed to maintain equity across the WUA outlets and among water users. The study concludes that the establishment of WUAs in Kyrgyzstan has helped to address the problem of water distribution and allocation among a large number of farmers. However, further training of farmers and managers is required to build their capacity to share water and ensure equity among users particularly during periods of less than optimal water supply. The findings of this research suggest that application of a pre-determined set of indicators can be a useful and cost effective tool to measure the performance of WUAs. This is particularly important for Central Asia where the performance of the recently established and state initiated WUAs to replace former collective farms is now a key element in future sustainable water management. The study identified uncertainties in the estimation of WUA water demands based on previous methods and suggests more attention and care required in calculating water requirements.     

Comparison between the efficiencies of surface and pressurized irrigation systems in Jordan

A study was carried out to determine the efficiencies of water use in irrigation in the Jordan Valley Project. The study aimed to evaluate, the overall or project efficiency (E_p) which includes: the irrigation system efficiency, being the combined conveyance and distribution efficiency (E_s); and the field application efficiency (E_a). Evaluation of these efficiencies includes the comparison of open canals with surface irrigation versus pressurized pipes with sprinkler or drip irrigation systems. Data was collected from different sources to achieve the above mentioned purposes, beside the field experiments which were carried out specially for this study.It was found that the overall or project efficiency (E_p) for open surface canal with surface irrigation under citrus was 53%. While it was 42% under vegetables. Whereas E_p for pressurized pipe systems was 68%, and 70% for sprinkler and drip irrigation methods, respectively.The E_s for an open canal, (King Abdullah Canal, KAC) was 65%. While it was 77% for pressurized pipe projects during 1989–1991. Concerning the E_a, it was found to be equal to 82% and 64%, for surface irrigation on citrus and vegetables, respectively. Whereas it was 88% for citrus under sprinkler, and 91% for vegetables under drip irrigation. These values for the field application efficiency are acceptable according to Finkle (1982). The low E_s value for the canal is due, mainly, to high evaporation and seepage, unreported deliveries, and unavoidable measurement losses. Whereas, in pressurized pipe projects, it is due to the unreported deliveries, unavoidable measurement losses, and leakage.     

灌区耗水量变化对地下水均衡影响研究

从宝鸡峡灌区水资源形成及转化的角度出发界定了灌区耗水量的概念。通过对灌区水量平衡关系分析,建立了灌区地下水量平衡模型,通过模型计算与分析,结果表明渠系及田间入渗补给量、地下水开采量是主要的地下水平衡要素;宝鸡峡灌区1991~2003年渠系蒸发及浸润损失量和渠系渗漏补给量总体呈递减的趋势,当渠首引水量和渠系利用系数一定时,渠系蒸发及浸润损失量和渠系渗漏补给量呈反比关系。灌区田间灌溉耗水量与田间灌溉入渗补给量也呈递减趋势;灌区地下水耗水量和地下水开采量总体呈上升趋势。     

宁、陕大型灌区地面灌溉存在问题与对策

讨论了陕西与宁夏二省 (区 )大型灌区骨干工程、田间配套工程情况 ;土壤盐渍化发展与治理措施效果 ;井渠结合灌溉、管理体制改革经验等。分析了灌溉定额偏大及土壤盐渍化等问题的成因与危害。针对各灌区存在的实际问题 ,提出了解决的对策与措施     

基于水量平衡下的灌区用水计划编制方法综述

为了精准指导农田灌溉,合理优化渠系输配水,提高水资源的利用率、灌区的管理水平和总效益,对灌区用水计划的编制方法展开了理论研究.将用水计划的编制过程概括为实时灌溉预报和渠系配水两部分,分别进行归纳整理和分析.在对国内灌区用水计划的编制方式进行了解的基础上,着重介绍了利用土壤水分平衡方程进行实时灌溉预报的方法,总结各参数预...     

Strategies to improve manual operation of irrigation systems in Sri Lanka

Improvements to normal operational procedures are investigated for the main types of irrigation system identified in Sri Lanka. Scheduled and unscheduled changes of flow regime the systems are likely to experience and the opportunities for improved operations related to the physical characteristics of each type are analyzed.Performance of several alternative manual operational procedures are evaluated and compared using a hydraulic model (Simulation of Irrigation Canal, SIC) for three different irrigation subsystem types (Single Bank canal; Double Bank canal; Canals with intermediate Storage). Results of these simulations show that current practice, based on a fixed frequency of operation of 12 hrs and a target water depth set to the spill level of the cross-regulator, is not far from the optimal for systems without on-line storage. A slight improvement can be expected if the frequency of operation is increased to 6 hrs. For systems with on-line storage it is recommended to split operational procedures into two parts, one related to the canal and one to the storage. Among different options investigated, discharge control at the downstream regulator of the storage appears to be the most reliable as it performs well whatever operation procedures are selected for the canal.Irrigation systems in Sri Lanka are subject to frequent positive flow changes (Supply fluctuations, Runoff, Return-flow changes). As far as water management is concerned, improvements to be expected from normal operation procedures appear to be somewhat limited because management of flow changes is not an objective. For instance little effort is made to harvest runoff under the current practices. One conclusion of the study is that new strategies for the harvest, storage and release of positive flow changes should be tested and, where appropriate, implemented to improve the overall efficiency of operation in irrigation systems in Sri Lanka.     

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.     

Wandering off the paths of planned innovation: The role of formal and informal intermediaries in a large-scale irrigation scheme in Morocco

For many years, large-scale irrigation around the world was based on state-driven water management and on a planned innovation process and diffusionist extension services. The purpose of this study is to show that formal extension services are not the only intermediaries of innovation and that local innovations take place at the initiative of farmers even in state-driven irrigation schemes. The study addressed changes in farming systems in a large-scale irrigation scheme in Morocco from two angles: a review of planned innovations and analysis of the actual innovation process at the village level. We show that the implementation of the large-scale irrigation scheme contributed to agricultural development, but often indirectly, and that it was not the only source of innovation. We also show how these results support recent thinking on innovation systems. Today, informal labour, neighbour and marketing networks are the main innovation intermediaries. New practices in agricultural extension are required to facilitate local innovations and to link farmers to more global innovation networks.     

石家庄井灌区农户灌溉行为调查及节水潜力分析

农户作为农业用水的主体,对其灌溉行为的研究成为目前关注的焦点。通过对石家庄市井灌区农户的大量调研,总结了农户灌溉行为的多样性及农户间的差异性,对产生灌溉行为差异的影响因素进行了深入分析。结合长期试验获得的该地区冬小麦/夏玉米优化灌溉标准,与农户实际的多样灌溉制度进行对比,从农户灌溉行为的角度分析了该地区的节水潜力,为合理灌溉制度的制定及农业水资源的管理提供了依据。     

陈垓引黄灌区渠系优化配水研究

该文以系统工程的原理方法,结合山东省陈垓引黄灌区北二干渠系统实际情况,分别以灌溉净效益最大和轮灌时间最短为目标,建立了作物最优种植面积和渠系优化配水模型,应用计算机求解,取得了满意的作物优化布局和优化配水成果。实践证明,本项成果在节水、灌溉增产、提高灌区科学管理水平等方面都有着十分重要的作用。     

依靠农民全面开展节水灌溉

缺水是世界普遍现象，节水是长期战略措施。开发农业节水，一方面要改善灌溉系统的基础设施，推广节水新技术，另一方面应应该吸收农民参与灌溉管理，充分发挥农民的积极性。农民参与灌溉管理是必然的趋势，也是农业节水最有效的措施之一。