The legal and administrative setting for the use of water resources in Mendoza, Argentina

The legal-administrative setting for the use of waterresources in Mendoza Province is founded on differentlegal rules. This includes the National Constitution,the Argentine Civil Code, National Laws, theConstitution of the Provincial State, the GeneralWater Law, (legal) administrative regulations of theGeneral Department of Irrigation.The current water law is based on the roman law, onthe Arab irrigation water rights which were brought toArgentina by the Spaniards and on the practices of theoriginal American pre-Colombian intermediate law.The latter is marked by a strong regional sense. Assuch, the water law is strongly influenced by theregions elements of nature and attempts to offersolutions to problems.The legal rules are discussed from a behavioral andorganizational perspective. Examples from the LowerTunuyan System are given to illustrate the day-to-dayeffects on irrigation water management.     

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.     

The quality of service provided by the irrigation department to the users associations, Tunuyan System, Mendoza, Argentina

The quality of service provided by the provincial Irrigation Department (DGI) to the Water Users Associations (UA), and subsequently by the UA's to the related water users, is based on the provincial water law. The intended volume of water being delivered per considered period further depends on the water availability and on the (crop irrigation) water requirements. The Service Level (SL) compares the intended water supply with the water supply that would be required to supply the entire irrigable area with sufficient water. As soon as the intended water delivery pattern is set, the measured actual delivery can be assessed against the intention. Several performance indicators are used in this context. Based on the assessment of the Water Delivery Performance Ratio and the Overall Consumed Ratio recommendations are made on changes which can be made to improve water use and reduce problems of waterlogging.     

Determining the optimal size of water users' associations

In 1985 the General Irrigation Department (DGI) of the Province of Mendoza, Argentina, launched a water users' associations reorganization program to attain administratively more effective associations. At that time there were 760 water users' associations (WUAs) managing a total irrigated area of 360,000 ha. Under the reorganization program all water users' associations of less than 1000 ha were merged into larger organizations. The main obstacle to the viability of small WUAs was the lack of adequate funding to perform their irrigation water management responsibilities. At that time it was thought that the ideal administrative area should range from 10,000 to 15,000 ha. Eight years after the reorganization, the total number of WUAs was reduced to 360. This paper reviews the experience with the reorganization program. It concludes that the optimal size should be between 3000 and 10,000 ha to minimize management costs. This conclusion is based on the detailed budgets of nine new WUAs administering from 500 to 14,000 ha.     

The Water Delivery Performance Within the Chivilcoy Tertiary Unit, Mendoza, Argentina

The 4th Chivilcoy tertiary unit (1630 ha)receives irrigation water from theMontecaseros canal. This canal and its 16tertiary units is managed by theMontecaseros Users Association (8531 ha),being one of the 13 UA's in the Rio TunuyanMedio irrigation system (81200 ha). The 4thChivilcoy unit was selected for performanceresearch because it is representative for amajor part of the Tunuyan system; itcontains (near abandoned) fields with waterlogging and salinity problems and fieldswith maximum attainable yields. This paperreports on performance indicatorsquantifying the water delivery to the 12quaternary units. Also the delivery ofwater to the 19 farms in the Los Saucesquaternary unit (109 ha) is quantified. Allflow data were measured with broad-crestedweirs fitted with pressure loggersmeasuring the head at 15 minutes intervals.Because of this short interval, the timingof water delivery could be monitored andcompared with the intended deliveryschedule.     

Performance of basin irrigation in the Lower Tunuyán River in Mendoza,Argentina

This paper results from the evaluation of irrigation in 37 different basins planted with perennial crops in the oasis irrigated by the Lower Tunuyán River in Mendoza, Argentina. The basins were evaluated by calculating management parameters through volumetric analysis. The results of this analysis were compared with the values obtained by means of the BRDRFLW mathematical model (Strelkoff, 1985). Four main elements were considered for analysis: application efficiency (ea), cut-off time (Tco), length (L), and net depth (DR), Multiple correlations were established and transferred to the graphics, which are simple and suitable for use by extensionists and farmers interested in improving basin irrigation efficiency.     

Performance of Water Users' Associations in the Lower Tunuyan Area, Argentina

The functioning of 19 Users' Associations(UA's) in the Tunuyan region was evaluatedon the basis of an 85-questionquestionnaire and related interviews. The collectedinformation indicates that the management know-how of the UA'sis not appropriate for the new tasks involved in managing thelarger command areas(average 4000 ha). For a UA to be able tomaintain and modernize the irrigationsystem, sufficient funds must be available.For this to occur, the fee collection ratiomust be as high as practical. In thiscontext we conclude that an up-to-datewater users register is needed to chargethe actual user with the correct fee.Participation of farmers in the UAdecreases sharply with increase infarm size. Some of the contacts betweenfarmers and the UA are related to farmerknowledge of on-farm irrigation technology.Strangely, no formal training for on-farmirrigation is available in the region. TheUA's should join forces in providingextension to the farmers. This could reducethe number of reported conflicts(misunderstandings) between the UA and, inparticular, the small (and relatively lowskilled) farmers.     

Division of irrigation water in The Fayoum,Egypt

The division of irrigation water in The Fayoum, Egypt, has been measured. Factors influencing this division are discussed: the hydraulic conditions at structures and canals, the operation regime of gates, lack of reliable gauge data for system operation, shortage of labour, and the water level in Lake Qarun. A deviation from uniform supply has been found for the entire Fayoum, but also along a lateral and sub-lateral. The reasons for this are discussed and suggestions for possible technical improvements of The Fayoum system are given.Abbreviations FWSBM Fayoum Water and Salt Balance Model Project - MSL Mean Sea Level at Alexandria - FID Fayoum Irrigation Department - mcm million cubic metres     

参与式灌溉管理的内涵及发展

灌溉是一个复杂的系统，不仅包括各式各样的灌溉技术，而且还包括错综复杂的社会因素。引用Uphoff、Oorthizen和Repetto的理论阐明灌区内各项水利活动的相互关系以及实行参与式灌溉管理的缘由。通过对调查实例的介绍，分析了农民用水协会和承包这两种主要的改革模式，提出了作者对我国参与式灌溉管理推广和发展的建议。     

Managing the water balance of The Fayoum Depression,Egypt

A study of the water balances of The Fayoum irrigated lands and Lake Qarun was made to investigate the management of the irrigation system and the efficiency of irrigation water use. The two water balances are strongly interrelated. The drainage flow to Lake Qarun and the water level of the Lake are in delicate balance. A rise in Lake level causes the inundation of adjacent land. Management of The Fayoum water balance assumes control over irrigation water flows, but this control has technical and organizational limitations. Also discussed is the influence of irrigation practices in The Fayoum on the water balance (e.g., the autumn flushing of fields and farmers' preference for not irrigating at night in winter). Notwithstanding a high overall efficiency, irrigation efficiency during the winter is low. The reasons for this are given, together with the constraints against improving system management. Improved uniformity of the division and application of irrigation water will enable a better technical control of flows and will result in better water management in The Fayoum. Abbreviations: FID — Fayoum Irrigation Department, 1 feddan (fe) — 0.4 ha, 1 mcm — 1 million cubic metres: an average annual flow of 3.17 m³/s gives 100 mcm, m³/fe.year — supplied volume (m³) per surface area (fe) per year: 1000 m³/fe.year equals 240 mm/year, MSL — Mean Sea Level     

丘陵区村镇水厂取水水源地水环境特征与综合治理-以四川省乐至县为例

对乐至县石河堰型水源地和水库型水源地进行调研,在对其自然环境和水环境对比分析的基础上,对石河堰型水源地和水库型水源地的水环境治理模式进行探讨,提出了源头控制结合生态修复的综合治理模式。     

Soybean yields and soil water status in Argentina: Simulation analysis

Recent changes in management of soybean production in Argentina may have large impacts on the soil water balance and on crop yield response. Changes in this system have included widespread adoption of a no-till management leaving crop residue on the soil surface, intensive cropping rotations (e.g. double cropping of wheat and soybean) so that the soil may not be fully recharged with water at the time of soybean sowing, and the occurrence of high water tables in a number of areas. The objective of this analysis was to assess the need to account for these factors in simulating soybean yields in Argentina. The influence of no-till management was simulated by simply decreasing the soil evaporation estimated for a bare soil by 70%. However, this alteration resulted in an over prediction in yield in many cases when it was assumed that the soil water content had been fully recharged at the initiation of the simulations. The difficulty with assuming a full soil water profile was confirmed when simulated yields were found to match well with observed yields when measured soil water content was used as an input to the model at the beginning of the soybean season. Finally, even with decreased soil evaporation there were still a few cases where simulated yield was less than observed yield. In these cases, a hypothetical water table, which relieved any drought stress once roots reached a depth of 1 m, resulted in yields that more closely matched observations. Overall, these results highlighted the need to estimate well both the influence of crop residue on soil evaporation and the soil water profile at sowing in simulating soybean yields in Argentina.     

Managing scarce water resources in Asia: The nature of the problem and can remote sensing help?

Water demands are outstripping supplies in many parts of Asia and causing conflicts, especially as rapidly urbanizing and industrializing areas compete with more traditional agriculture on alluvial plains near expanding metropolises. The environment is increasingly being seen as a legitimate and important user of water, often in competition with irrigation, domestic, industrial, hydropower and community uses of water. Any future scenario requires an improvement in water productivity, especially in agriculture. Surface and ground water supplies are not well regulated owing primarily to a weak knowledge base, analytical capacity in addition to a number of traditional institutional, governance, political and other factors. Water policy makers have, therefore, to work out strategies for integrated water and environmental management, which rely on a proper knowledge base of the basin hydrological and pollution conditions. Examples from various countries in Asia are elaborated in this paper to demonstrate how spatially distributed evapotranspiration data from remote sensing, in conjunction with other key data, can help to build the knowledge base for integrated basin scale water management. Remote sensing is not a solution, but it provides key data that is difficult to access by conventional data collection methods.     

山东禹城市用水协会的实践与问题

禹城市自2001年开始在小型灌区成立用水者协会，正处于实践的初期，从运行效果来看，用水者协会(WUA)不但解决了小型灌区的管理维护、农民用水问题，同时还为推行农业节水提供了很好的平台。以禹城市用水者协会的发展过程为例，分析它的初步效益、潜在效益、存在的问题和发展方向，以期为农村小型灌区的改革提供参考。     

Managing water in rainfed agriculture—The need for a paradigm shift

Rainfed agriculture plays and will continue to play a dominant role in providing food and livelihoods for an increasing world population. We describe the world's semi-arid and dry sub-humid savannah and steppe regions as global hotspots, in terms of water related constraints to food production, high prevalence of malnourishment and poverty, and rapidly increasing food demands. We argue that major water investments in agriculture are required. In these regions yield gaps are large, not due to lack of water per se, but rather due to inefficient management of water, soils, and crops. An assessment of management options indicates that knowledge exists regarding technologies, management systems, and planning methods. A key strategy is to minimise risk for dry spell induced crop failures, which requires an emphasis on water harvesting systems for supplemental irrigation. Large-scale adoption of water harvesting systems will require a paradigm shift in Integrated Water Resource Management (IWRM), in which rainfall is regarded as the entry point for the governance of freshwater, thus incorporating green water resources (sustaining rainfed agriculture and terrestrial ecosystems) and blue water resources (local runoff). The divide between rainfed and irrigated agriculture needs to be reconsidered in favor of a governance, investment, and management paradigm, which considers all water options in agricultural systems. A new focus is needed on the meso-catchment scale, as opposed to the current focus of IWRM on the basin level and the primary focus of agricultural improvements on the farmer's field. We argue that the catchment scale offers the best opportunities for water investments to build resilience in small-scale agricultural systems and to address trade-offs between water for food and other ecosystem functions and services.     

国外水利工程管理方法对我国水利工程的启示

水利工程的管理直接影响着工程建设的成本、周期和质量,文章分析了发达国家对水利工程管理体制,并从中找到了适合我国水利工程有益的东西,希望能给同行起到一些借鉴作用.     

Land and water rights and the design of small scale irrigation projects: The case of Baluchistan

In countries around the world where small-scale irrigation systems are being improved, the design and functioning of these upgraded systems will be greatly enhanced if pre-existing patterns of land and water rights and established procedures for system operation are taken into account. An appreciation of these rights and procedures can greatly influence the layout of the water distribution network, water management practices, anticipated cropping patterns, and the related incidence of project benefits. Failure to do so will almost certainly have an adverse effect upon the functioning of the irrigation system, and can often result in serious conflicts. This is illustrated by the case of small-scale irrigation development in Baluchistan Province, Pakistan, where limited analysis of property rights and management practices and lack of consultation with intended beneficiaries caused major delays during the initial stages of project implementation. However, by introducing a methodology for social action that included an assessment of property rights and extensive consultation with affected households during the design and construction phases, the physical features and operating procedures for the upgraded irrigation system were crafted in a manner which maximized economic returns within the range of options acceptable to the local community.     

Crop rotations in Argentina: Analysis of water balance and yield using crop models

Cropping schemes have developed in east-central Argentina for rainfed soybean (Glycine max Merr.) production that invariably employ no-tillage management. Often these schemes include growing soybean in a sequence of crops including wheat (Triticum aestivum L.) and maize (Zea mays L.). The full impact of various rotation schemes on soil water balance through a sequence of seasons has not been explored, although the value of these rotations has been studied experimentally. The objective of this work was to investigate through simulations, potential differences in temporal soil water status among rotations over five years. In this study, mechanistic models of soybean (Soy), maize (Maz), and wheat (Wht) were linked over a five-years period at Marcos Juárez, Argentina to simulate soil water status, crop growth, and yield of four no-till rotations (Soy/Soy, Soy/Wht, Soy/Maz, and Soy/Maz/Wht). Published data on sowing dates and initial soil water contents in the first year from a no-till rotation experiment were used as inputs to the model. After the first year, soil water status output from the model was used to initiate the next crop simulation in the sequence. The results of these simulations indicated a positive impact on soil water balance resulting from crop residue on the soil surface under no-till management. Continuous soybean and the two-year soybean/maize rotation did not efficiently use the available water from rainfall. Residue from maize was simulated to be especially effective in suppressing soil evaporation. Thus, the Soy/Maz simulation results indicated that this rotation resulted in enhanced soil water retention, increased deep water percolation, and increased soybean yields compared with continuous soybean crops. The simulated results matched well with experimental observations. The three-crop rotation of Soy/Maz/Wht did not increase simulated soybean yields, but the additional water retained as a result of decreased soil evaporation resulting from the maize residue allowed the addition of a wheat crop in this two-year rotation. Simulated soybean yields were poorly correlated with both the amount of soil water at sowing and the rainfall during the cropping period. These results highlight the importance of temporal distribution of rainfall on final yield. These models proved a valuable tool for assessing the consequences of various rotation schemes now being employed in Argentina on temporal soil water status, and ultimately crop yield.     

Social power,water control and irrigation systems

The principal finding of the study is that social power positions held by Egyptian farmers sharings a common watercourse do not have significant influence in the farmer's ability to control irrigation water distribution. Other variables used to describe irrigation management; location on the water course and farmers' use of more than one source of water to irrigate; also do not yield any explanations as to why particular farmers have more control over their irrigation than others. Farmers who have more control are less likely to be affected by other farmers' actions, physical problems on delivery canals, breakdown in pumps, and government officials actions. While differences in irrigation control among farmers exist, no single cause is identified. Two explanations for the findings are (1) water control is sufficient for a large percentage of Egyptian farmers, and (2) adequately explaining irrigation behavior cannot be done with separate variables.Deceased