Large-scale Irrigation Systems Research Articles

Conjunctive groundwater use: a ‘lost opportunity’ for water management in the developing world?

Conjunctive groundwater use with surface-water resources has only occasionally been considered in the hydrogeological literature and at scientific conferences (e.g. Bredehoeft and Young 1983; Sahuquillo 2002), although in terms of practical water management it represents one of the most important responses to improving drought water-supply security and for long-term climate-change adaptation, and in terms of underpinning science its design requires a refined understanding of resource interconnectivity (both naturally and perturbed by irrigation works or practices) and of aquifer salinisation processes. The aim of this essay is to provide an overview of current conjunctive use in the developing world for both irrigated agriculture and urban water-supply, and to highlight the great potential that planned ‘conjunctive management’ has as a climate-change adaptation strategy. It is primarily relevant to larger alluvial plains, which often have important rivers, large-scale irrigation systems and major aquifers in close juxtaposition—although the potential for conjunctive management can be present in a wider range of settings. There is no rigorous definition for ‘conjunctive use’; however, for the present purpose it is proposed to consider only situations where both groundwater and surface water are developed (or co-exist and can be developed) to supply a given urban area or irrigation canal-command—although not necessarily using both sources continuously over time nor providing each individual water user from either source. Adopting this rather narrow definition excludes consideration here of artificial recharge of aquifers with surface runoff or by rain-water harvesting (without direct supply from the surface-water source), use of groundwater pumping to support river baseflows (without direct supply from water wells) and catchment-scale integrated water-resources management embracing everything from flood protection to wastewater reuse (because of insufficient finance as yet to apply this in the developing world)—although it is recognised that all such techniques can play an important role in water-resources management. A key characteristic of conjunctive use is that it deploys the large natural groundwater storage associated with most aquifers to buffer the high flow variability and drought propensity of many surface watercourses (Foster et al. 2010a), and is thus capable (at varying levels of efficiency) of achieving: (1) much greater water-supply security—by taking advantage of natural aquifer storage, (2) larger net water-supply yield than would generally be possible using one source alone, (3) better timing of irrigation-water delivery—since groundwater can be rapidly deployed to compensate for any shortfall in canal-water availability at critical times for crop growth, (4) reduced environmental impact—by counteracting land water-logging and salinisation, and (5) excessive river-flow depletion or aquifer overexploitation. These benefits have been the driving force for spontaneous conjunctive use of shallow aquifers in irrigation-canal commands worldwide.

Head-enders as stationary bandits in asymmetric commons: Comparing irrigation experiments in the laboratory and the field

The emergence of large-scale irrigation systems has puzzled generations of social scientists, since they are particularly vulnerable to selfish rational actors who might exploit inherent asymmetries in the system (e.g. simply being the head-ender) or who might free ride on the provision of public infrastructure. As part of two related research projects that focus on how subtle social and environmental contextual variables affect the evolution and performance of institutional rules, several sets of experiments have been performed in laboratory settings at Arizona State University and in field settings in rural villages in Thailand and Colombia. In these experiments, participants make both a decision about how much to invest in public infrastructure and how much to extract from the resources generated by that public infrastructure. With both studies we find that head-enders act as stationary bandits. They do take unequal shares of the common-pool resource but if their share is very large relative to downstream participants' shares, the latter will revolt. Therefore for groups to be successful, head-enders must restrain themselves in their use of their privileged access to the common-pool resource. The comparative approach shows that this result is robust across different social and ecological contexts.

Strategies and engineering adaptions to disseminate SRI methods in large-scale irrigation systems in Eastern Indonesia

The system of rice intensification (SRI) developed in Madagascar has been controversial in part because there have been no large-scale, long-term evaluations of the impact of its alternative methods. This paper summarizes experience with the dissemination of SRI practices across eight provinces in Eastern Indonesia over nine seasons from 2002 to 2006 under a major irrigation project. The Decentralized Irrigation System Improvement Project (DISIMP) was financed by the Japanese Government with project management by a Nippon Koei consultant team. SRI has been introduced in Indonesia via several organizations and in different parts of the country starting in 2000. The evaluation reported here, made by the DISIMP technical assistance team, is based on data from 12,133 on-farm comparison trials that covered a total area of 9,429 ha. Under SRI management, average paddy yield increase was 3.3 t/ha (78%). This was achieved with about 40% reduction in water use, 50% reduction in chemical fertilizer applications, and 20% lower costs of production. The farmers whom DISIMP was assisting to take up SRI were usually cultivating their paddy fields individually within irrigation systems where it was difficult to reduce water applications as recommended for SRI. Accordingly, innovations had to be made in soil and water management to create relatively aerobic soil conditions so that farmers could get the more productive rice phenotypes expected from SRI practice. This article describes the modifications made to adapt SRI concepts, pointing to the value of introducing in-field ditches, which was confirmed through paddy tract surveys. This experience and analysis showed how SRI methods could be utilized within irrigation systems where water management was not (yet) tailored to SRI production practices. Subsequently, modifications in irrigation system management are being made to be more supportive of SRI cultivation.

Crossed destinies: 30 years of research in large-scale irrigation systems

La « grande hydraulique » fut un modele scientifique et centralisateur d’amenagement par l’irrigation, concu et gere par des corps d’ingenieurs bâtisseurs depuis la deuxieme partie du xix e siecle. Traversant plusieurs crises, elle a constitue de ce fait un champ de recherche exceptionnel, inspirant une multitude d’ecoles de pensee. Au cours des 30 dernieres annees, trois paradigmes forts fondes sur l’action preeminente de l’Etat, puis sur l’action collective, et plus recemment sur l’action individualiste et la regulation par le marche, ont fortement influence les programmes de recherche mais aussi les politiques publiques sur l’irrigation. Si l’enrolement de la recherche au service d’Etats amenageurs, ou de bailleurs de fonds, a ete tres marquant pour le domaine de l’irrigation, le propos pourrait etre sans doute elargi a d’autres domaines (sciences agronomiques, par exemple) et a d’autres acteurs. La proximite croissante entre la recherche et la societe constitue en meme temps une opportunite pour une recherche vivante operant dans un double souci de rigueur et de pertinence. Ceux-ci s’opposent au quotidien, mais peuvent se conjuguer dans le temps.

Volumetric water control in a large-scale open canal irrigation system with many smallholders: The case of Chancay-Lambayeque in Peru

Volumetric water control (VWC) is widely seen as a means to increase productivity through flexible scheduling and user incentives to apply just enough water. However, the technical and social requirements for VWC are poorly understood. Also, many experts assert that VWC in large-scale open canals with many smallholders is not feasible. This article debates the practice of VWC, drawing on field studies in the arid North Coast of Peru. Here the large-scale Chancay-Lambayeque irrigation system achieved high allocation, distribution and financial performance with on demand delivery to some 22,000 smallholdings, under a VWC approach, with full cost recovery for operation and maintenance. This study shows there are options to promote VWC if its different elements – volumetric allocation, distribution, metering and pricing – are planned together.

Multi-Objective Planning Model for Large Scale Irrigation Systems: Method and Application

An increase in demand, and droughts in recent years have resulted in the need for tools to allocate limited water between users in different regions in order to achieve economic, social and environmental benefits. Multi-objective planning is an important decision support tool for natural resource management. Planners, decision makers and stakeholders use this approach in the decision-making process. In this research, a multi-objective planning model was developed and applied on the Menemen Left Bank Irrigation System of the Lower Gediz Basin in Turkey. The aims of the model were to increase the benefit from production, to increase the size of the total area irrigated, and to reduce the water losses occurring at network level. The model was applied to an open channel system consisting of 44 tertiary channels receiving water from three secondaries, serving an area of 3,606 ha. The model predicted a 20.63% increase in income, and a 29.26% decrease in the total irrigation water requirements of crops dependent on projected changes in the actual crop pattern of the research area. This decrease caused a reduction of 29.90% in expected water losses over the network as a whole. The operation of the model enabled optimum productivity and income at the system level per unit of land and water resources.

Performance diagnosis of Mae Lao Irrigation Scheme in Thailand (I) Development of Unsteady Irrigation Water Distribution and Consumption model

The Mae Lao Irrigation Scheme is one of the largest irrigation projects in Northern Thailand. According to the field reconnaissance, water shortage usually occurs during the dry season. And it is very difficult to equally distribute available water to the paddy fields from the upstream to the downstream parts of the system. To understand and identify the causes of the problems, the measurement of water level and flow rate along all canals may be effective. However, it is not easy to achieve this in such a large-scale irrigation system. Thus, the numerical simulation becomes the second option. The objective of this study is to identify and quantify the real water shortage causes by developing an Unsteady Irrigation Water Distribution and Consumption model which can simulate the water movement and consumption in the whole irrigation system. The beneficial area of the right main canal is modeled based on the physical aspect of the system. The components of the model consist of canal networks, control structures, and paddy fields. A canal is divided into several portions called reach. The Saint-Venant equations are applied to describe the unsteady water movement in each reach. Flow movement at the control structure is expressed by the boundary condition. The paddy fields are modeled to make paddy block and connected to each reach. The water consumption in each paddy block is estimated by Paddy Tank model. The numerical model is successfully developed showing the ability to simulate the water movement and consumption properties in this irrigation system.

Is the hydraulic hypothesis dead yet? Irrigation and social change in ancient Yemen

Irrigation played an important role throughout ancient Southwest Arabian histories. Irrigation structures provide some of the earliest evidence of crop agriculture and large-scale flash floodwater irrigation systems sustained ancient states; the region thus offers important potential for reconsidering links between irrigation and social change. This paper examines millennia-long connections between social relations and the increasing technological and organizational complexity of irrigation in ancient Yemen. While the hydraulic hypothesis in its original deterministic formulation does not adequately account for the complexity and diversity of regional histories, large centrally managed irrigation systems played an indisputably significant role in Southwest Arabian state formation. Irrigation not only generated the food to sustain burgeoning populations but, just as importantly, afforded ancient kings the ideological prestige of commanding transformation of hyper-arid areas into lush, bountiful oases.

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Investigation of Integrated Management of Large-Scale Irrigation and Aquaculture Systems

The importance of nonirrigation uses of irrigation water to the livelihoods of the rural poor living close to irrigation systems has generally been ignored both in planning and operating these systems. An improved understanding of competition and complementarity of irrigation and nonirrigation uses is essential for increased productivity of irrigation water. This paper selected two typical types of large-scale irrigation systems as case study sites, i.e., the Lower Bhavani Project in Tamil Nadu, India—a canal-based irrigation system and Mahaweli System H, Sri Lanka—a tank-based irrigation system, and explored their potential for and constraints to integrated management for irrigation and aquaculture. The results revealed that for irrigation canals water supply reliability, canal flow velocity, and cage anchorage but for irrigation tanks water, supply reliability may impose constraints to integration of cage-based fish farming. However, the potential can be improved through more responsive operation and ma...

Application of a 45° Bend Pipe with a Bypass Flow Meter without Changing the Flow Direction or the System Construction

Sprinkler systems are widely used in agricultural production. Rapid and accurate determination of flow discharges is required in order to optimize the control and management of sprinkler systems. A number of studies on measurement methods and instruments have been published, but these options are very expensive. With the aim of finding techniques that are low in cost and require low energy consumption, the use of 90 bend pipe flow meters has been examined, but the equipment is difficult to install. In this study, we found that 45 bend pipes can be installed on any main straight pipe section without influencing the flow direction or pipeline system construction. The main flow discharge can then be defined by the proportion of the bypass flow discharge. The procedure for the design of bypass flow meters was accomplished by introducing orifices with different diameters into a bypass route based on the obtained experiment results. Since the bypass flow discharge is very small in comparison with the main pipe flow discharge, a small flow meter can be installed on the bypass route with considerable reduction in cost. Moreover, a float-type flow meter can also be installed on the bypass route in order to rapidly and accurately determine the flow discharge. Consequently, the control and management of the quantity of irrigated water are easier and more convenient. Accurate and timely water measurement is important for large-scale irrigation systems in agriculture.

Large-Scale Reservoir Construction and Political Centralization: A Case Study from Ancient Korea

The relationship between centralized political authority and the construction of large-scale irrigation systems has been a major research topic in both anthropology and archaeology for many decades. One of the objects of this research has been to determine whether large-scale irrigation works were a cause or a result of political centralization. Some scholars (e.g., Wittfogel) have argued that construction of such projects played a critical role in the emergence of centralized, bureaucratic social structures. Others believe that large-scale irrigation works were constructed only after a centralized government emerged, and that before this, local people managed relatively small-scale cooperative irrigation works without intervention of a centralized political authority. This paper argues that large-scale reservoirs were constructed only after and because of the appearance of centralized political organization, in this case, the Silla Kingdom in ancient Korea.

A Simulation Model to generate the Demand Hydrographs in Large-scale Irrigation Systems

The study reports the development of a model for the generation of daily volumes and hourly discharge hydrographs, withdrawn from on-demand pressurised irrigation systems. The model is based on the simulation of the water budget at the level of each single hydrant. Under the hypothesis that the initial soil moisture is at field capacity, once the soil water reserve falls down a pre-defined limit value, irrigation occurs. The farmer's management strategy was simulated using a stochastic approach allowing for the generation of the initial time of each irrigation at each hydrant. The aggregation of the hydrant hydrographs generates the discharge hydrographs at the upstream end of the network. The calibration of the model was carried out comparing the generated and measured hydrographs at the upstream end of an irrigation network in Southern Italy. The results obtained are satisfactory even though they require further verifications. The comparison has generally shown a good correspondence, particularly for daily withdrawn volumes. The simulated hourly discharges showed, sometimes, hourly peaks higher than the measured ones. The proposed model, when well calibrated, can be used for the design of new irrigation systems as well as for the analysis of existing ones.

Investigation of Large-scale Field Irrigation System in Shamoh Region

Investigation of Large-scale Field Irrigation System in Shamoh Region

Construction of Large-scale Field Irrigation System in Shamoh Region

Construction of Large-scale Field Irrigation System in Shamoh Region

Consumptive water use to feed humanity - curing a blind spot

Abstract. Since in large parts of the world it is getting difficult to meet growing water demands by mobilising more water, the discourse has turned its focus to demand management, governance and the necessary concern for aquatic ecosystems by reserving an "environmental flow" in the river. The latter calls for attention to river depletion which may be expected in response to changes in consumptive water use by both natural and anthropogenic systems. Basically, consumptive use has three faces: runoff generation influenced by land cover changes; consumptive use of water withdrawn; and evaporation from water systems (reservoirs, canals, river based cooling). After demonstrating the vulnerability to changes in consumptive use under savanna region conditions - representative of many poverty and hunger prone developing countries subject to attention in the Millennium Development Goal activities - the paper exemplifies; 1) changes in runoff generation in response to regional scale land cover changes; 2) consumptive use in large scale irrigation systems. It goes on to analyse the implications of seeing food as a human right by estimating the additional consumptive use requirements to produce food for the next two generations. Attention is paid to remaining degrees of freedom in terms of uncommitted water beyond an environmental flow reserve and to potential food trade consequences (so-called virtual water). The paper concludes that a human-right-to-food principle will have major consequences in terms of altered consumptive water use. It will therefore be essential for humanity to address river depletion to avoid loss of resilience of the life support system. This will demand a deep-going cooperation between hydrology, ecology and water governance.

Understanding water delivery performance in a large-scale irrigation system in Peru

During a two-year field study the performance of the water delivery was evaluated in a large-scale irrigation system on the north coast of Peru. Flow measurements were carried out along the main canals, along two secondary canals, and in two tertiary blocks in the Chancay-Lambayeque irrigation system. The most important finding was the unexpectedly high accomplishment rate of the actual delivery at field level compared with the on-request schedule. Delivery performance ratios (DPRs) were very close to unity. Three main factors were identified contributing to this good performance: the high degree of accountability of the Water Users' Association towards the water users, the skills and experience of the operators to deal with the - difficult to operate - undershot sliding gates, and the high degree of mutual social control among the water users and their high labour input. It is concluded that the institutional design and skills of operators made a good delivery performance possible, overcoming the difficulties caused by the irregular water supply, infrastructure and on-request schedule

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.

Can development of water resources reduce poverty?

The United Nations Millennium Declaration and resolutions at the 2002 World Summit on Sustainable Development give high priority to poverty reduction in international development agenda for the next decade and a half. It is now widely recognized that water resources development and management play a fundamental role in sustainable growth and poverty reduction. However, investments in water resources development, which were considered a high priority by governments and aid agencies for decades, have fallen drastically. The key question addressed in this paper is: Can water resources development reduce poverty? It examines the impacts of past investments on water resources development and management, (especially on irrigation), on poverty reduction. It is shown that past investments in irrigation development have made a significant contribution to alleviating poverty. In recent years investments made by private farmers in groundwater irrigation may have had a larger impact on livelihoods for poor people than the public investments in large-scale surface water irrigation systems. It is argued that there is not a single silver bullet to reduce poverty though water resources development or management. The best chance for lasting and sustainable impact on poverty is likely to be achieved through a combination of sustainable water resources development, combined with the development of appropriate pro-poor institutions and technologies.

Migration and intensification of water conflicts in the Pangani Basin, Tanzania

Migration of population in search of better sources of water is a widespread phenomenon in Africa with a long-standing history. In the case of the Pangani River Basin in the North East of Tanzania, migration has led to intensive water conflicts caused by the convergence of pastoralists and farmers, traditional irrigation systems and large scale irrigation systems; and other uses including hydropower generation in the basin. The main determinants of these water conflicts in the basin include rapid population increase of both human beings and livestock. The rapid population dynamics of both livestock and human population as a result of natural increase and migration generate additional demands for water as do the irrigation systems, which allow little water downstream for other uses such as generation of power and land alienation, resulting in poor water rights management. Measures that have been taken to resolve some of these water conflicts including the improvement of irrigation systems so they do not waste water and application of environmental impact assessment techniques wherever new projects are introduced in the basin.