Water Productivity in Irrigation Systems

Abstract

Situated in the south of the Iberian Peninsula, the Guadalquivir river basin's irrigation systems suffer from frequent water shortage due to the shortfall in this basin's average hydrological balance. Viable solutions are non-existent in the Spanish hydrological planning framework, neither in the Guadalquivir river basin nor in what the National Hydrological Plan (Ministerio de Medio Ambiente, 2001) has to offer. Therefore, it is necessary to turn to economic tools in order to find solutions, which will affect the demand or the reallocation of resources. In this study, a method that calculates the water productivity of an irrigation system and compares the result with the water cost paid by farmers is proposed and put into practice. The economic viability of resource reallocation and the application of the cost recovery principle can be studied using this data and can help with the more efficient use of water resources.     

An Analytical Hierarchy Model for Assessing Global Water Productivity of Irrigation Networks in Iran

Water Resources Management - Water management decisions in irrigation networks are often characterized by complexity, irreversibility and uncertainty. In the present study, an analytical hierarchy...     

Optimal Design of Pressurized Irrigation Networks to Minimize the Operational Cost under Different Management Scenarios

The adoption of measures leading to higher efficiencies in the use of both water and energy in water distribution networks is strongly demanded. The methodology proposed combines a multi-objective approach and a financial analysis to determine de optimal design of pressurized irrigation networks which entails the minimization of both the investment cost and operational cost under three operating scenarios that incorporate energy saving strategies: 1- all hydrants operate simultaneously; 2- hydrants are grouped into sectors and irrigation turns are established; 3- the on-demand operation of the network is assumed. This methodology has been applied in a real irrigation network located in Southern Spain showing that the lowest overall design cost (investment and operational costs) is achieved in scenario 2. The comparison of the selected solutions in the three proposed scenarios with the current network design considering the total fulfillment of irrigation requirements showed that operational cost savings between 65% and 76% could be achieved.     

An Empirical Assessment of On-Farm Water Productivity using Groundwater in a Semi-Arid Indian Watershed

Realistic estimation of irrigation volume applied to any crop at farm level generally requires information on event based discharge rates and corresponding periods of irrigation application. Use of mean seasonal discharge rates leads to erroneous estimation of volume due to unaccounted seasonal fluctuations in the water table, upon which the discharge rate of tube well is dependent. In the absence of such information, an alternative approach of estimating farm level water application based upon water table fluctuation data has been adopted in this study. The total actual water extracted during each irrigation event from the watershed was distributed among the farms irrigating crops in proportion to the product of irrigation time and the pump capacity (h_p). Volume of water withdrawal concurrent to an irrigation event was computed based on the water level fluctuations in the wells in conjunction with potential recharge contribution from the surface storage structures to the groundwater aquifer. A production function approach was used to estimate the marginal productivity of water for selected crops at various stages of plant growth. Water, as an input in the production function, encompassed either in-situ soil moisture storage from rainfall or irrigation from groundwater or both. The inter-season as well as intra-season groundwater use, and the consequent groundwater withdrawals were analyzed based on the marginal value and output elasticity of water at different crop growth stages during the season. The cotton crop realized marginal value product of water, ranging from Rs. 1.03/m³ to Rs. 10.43/m³ at different crop growth stages in cotton. Castor crop had the marginal value product ranging from Rs. 2.89/m³ to Rs. 6.81/m³. The availability and use of water, including soil moisture, in the two seasons, coupled with the local harvest prices received, yielded the differential marginal values of water.     

Water Productivity in a Rigid Irrigation Delivery System

The rotational irrigation water delivery (warabandi) system practiced in the Indus river basin of Pakistan has continued for 100 years. Irrigation water allocated to the farmers under the warabandi system is proportional to farm size and is fixed. This rigid allocation system has been partly justified by its contribution to social equity though this may have been at the cost of economic gains. In order to assess the operation of warabandi’s basic rules, a farmers’ survey was completed from 124 farmers located on five watercourses. A questionnaire was administered to each farmer and farm management data were gathered. As fresh water resources are under stress and becoming scarce their efficient use in all applications should be assured in water allocations. It is shown from the survey results that water allocation based on very limited criteria does not maximize the socio-economic benefits gained from the use of scarce water. Thus, it is suggested that the existence or non-existence of fresh groundwater resources along with other critical variables should be taken into consideration when making canal water allocation decisions. Missed water deliveries due to failure of the canal system appear to be the largest cause of losses. Water charges need to be increased to fund large improvements in canal maintenance programs. It is pointed out that a framework should be developed as a tool to improve water productivity for Pakistan. This should include: consideration of the gross area of a tertiary canal, sensitivity of crop growth stage to water shortage, crop value, bias of allocation towards most water use efficient areas and water use efficient crops, the potential losses from water deficiency.     

水稻无水层灌溉水分生产率分析

通过较长时间小区试验,对水稻3种灌溉方法的产量、用水量、水分生产率进行了研究。结果表明:无水层灌溉与薄露灌溉、习惯灌溉相比,早稻分别增产651,990 kg/hm2,增产率为10.3%、16.5%;晚稻分别增产717,1 175 kg/hm2,增产率为9.9%、17.4%。同时,灌溉水量早稻分别节水830,3 150 m3/hm2,节水率为46%、69%;晚稻分别节水1 410,2 955 m3/hm2,节水率为58%、74%。无水层灌溉早稻、晚稻水分生产率分别为2.67,2.94 kg/m3,达到了国际领先水平。     

河南省农业灌溉水分生产力区域分异研究

农业灌溉水分生产力是提高区域灌溉效率、发展节水农业和调整产业结构的重要依据,对水资源管理和决策也具有重要意义。在计算2011年河南省18个地级市的灌溉水分生产力、分析其区域分异特征的基础上,将河南省灌溉水分生产力分为高值区、中值区和低值区三个分级区,并确定了灌溉水分生产力区域分异的影响指标,利用灰色关联度法分别对不同分级区灌溉水分生产力的影响因素进行了定量评价。结果表明:灌溉水分生产力不仅受作物产量和灌溉水量的影响,同时还与作物有效降水量、农业机械总动力等因素密切相关。     

Water Use Efficiency and Productivity of the Irrigation Districts in Southern Alberta

The data envelopment analysis (DEA) model was used to estimate the technical efficiency (TE) scores, the Malmquist total factor productivity (TFP) indices, and their implicit input shadow shares for 12 irrigation districts in Southern Alberta using data for the period 2008–12. The main purpose was to establish benchmarks so that future increases in conservation, efficiency and total factor productivity of water use (major goals of Alberta’s Water for Life strategy) can be assessed. Results of an input-oriented DEA model indicated that the irrigation districts were, on average, 84.3 % technically efficient in their input use, primarily the net water diverted. The output-oriented model indicated that the irrigation districts, alternatively, could expand their total irrigated areas by 58.3 % with the current level of input use. Over the period 2008–12, the year-to-year mean Malmquist TFP for the irrigation districts of Southern Alberta was estimated to be 0.98 %. Net water diverted was identified as the most important contributing input (76 %) to the TFP change. The second and third contributing factors were pivot irrigation technology (6 %) and precipitation (5 %).     

An Objective Multi-Criteria Evaluation of Water Management Scenarios

Advanced computer models are commonly used to simulate reservoir system's performance. If the number of possible management scenarios is large, it can be extremely difficult to follow related system's operation and get a valuable picture on its spatial and temporal behavior. The decision maker or analyst can be overburdened by quantity and complexity of information generated by model, particularly if system operation is repeatedly simulated for multiyear periods. Related problem is how to select the scenario with most desired long-term consequences. Possible approach is to use selected parts of model's output and re-interpret system behavior by means of certain performance indicators, create appropriate decision matrix and perform multi-criteria analysis to rank decision alternatives (scenarios). The paper proposes a methodology that includes: (1) multiyear simulations of system operation; (2) computing spatially and temporally distributed systemperformance indices such as supply reliability, resiliency and vulnerability; (3) unbiased entropy-based weighting the importance ofperformance indices; and (4) final ranking of scenarios by means of multi-criteria analysis. The number of scenarios and number of performance indices is not restricted, and to account for possibly large sets of scenarios, an ideal-point-distance multi-criteria method TOPSIS is suggested. Proposed methodology appeared to be confident and robust in proof-of-concept application in Brazil.     

Developing Strategies for Agricultural Water Management of Large Irrigation and Drainage Networks with Fuzzy MCDM

Sustainable water resources management aims at increasing the efficient use of water and achieving food security. This work proposes a generalized novel spatial fuzzy strategic planning (SFSP) in combination with multi-criteria decision making (MCDM) and a conceptual agricultural water use model for determining sustainable agricultural water management strategies. The proposed framework is applied to an irrigation and drainage network in Iran, which constitutes a large-scale water resource system. A spatial strength, weakness, opportunity, and threat (SWOT) analysis of internal and external factors related to agricultural water management is applied in this work. Possible water management strategies were ranked with the MCDM approach that combines the Analytic Hierarchy Process (AHP) and the Fuzzy technique for order-preference by similarity to ideal solution (TOPSIS). The AHP estimates the criteria weights and the TOPSIS model prioritizes the agricultural water management strategies. The results of SWOT analysis show that the final scores of the internal and external factors are equal to 2.9 and 2.73, respectively. Accordingly, the most attractive strategic type is a SO (aggressive) strategy, and a combination of structural and non-structural strategies (SO, ST, and WO strategies) are the top-ranked ones. Proposed strategies for water supply and demand management are the development and rehabilitation of the physical structure of water resources system of irrigation network, improvement of operation management and maintenance of water resources system, wastewater management, and inter-basin water transfer within the irrigation network. The results indicate that the total annual volume of agricultural water under normal conditions is about 1.8 billion cubic meters, of which about 1707 million cubic meters (95%) issue from surface water sources and 90 million cubic meters (5%) from groundwater sources. The proposed model and the calculated results provide viable and effective solutions for the implementation of sustainable management of water resources and consumption in large-scale water resources systems.

     

Water and Radiation Effect on Sweet Sorghum Productivity

Suitability of sweet sorghum in Greece, where irrigation supply during crop development is limited as rainfall is scarce and evapotranspiration loss is high, is examined in relation with radiation availability. A two-year field experiment was conducted, in central Greece, imposing four soil water regimes via different irrigation treatments: (1) Highly irrigated, (2) Highly irrigated till anthesis when irrigation stopped, (3) Medium irrigated, and (4) Low irrigated. It was found that above-ground dry biomass production from non-water-stressed sweet sorghum plants suggests a high productivity potential among C₄ crops. Under water shortage, radiation use efficiency may be significantly lower. Radiation use efficiency seems to be linearly related to water consumption. Stressed plants (probably except severely stressed) seem to use available water more efficiently than unstressed plants. The slope of the line relating dry matter produced and water evapotranspired increases the sooner the stress is sensed. Yield reduction resulting from post-anthesis irrigation stopage is very little. High water use efficiency values tend to be related with low radiation use efficiency values.     

高扬程多梯级泵站提水灌区用水管理调度技术

概括介绍了水利部“948”计划项目“高扬程多梯级泵站提水灌区用水管理调度技术”的技术成果，主要包括高扬程提水灌区用水管理信息系统，灌溉渠系水流模拟仿真系统，渠道闸门太阳能自动控制系统和微功耗大容量自记式水位计等，这些成果在注重创新研究的同时，又强调技术的实用性，在灌区用水管理中得到了实际应用。     

节水灌溉工程管理方法浅析

1　节水工程存在的问题　　随着工农业生产规模的不断扩大 ,水资源短缺的问题在沈阳市日益突出 ,而在农业用水占全市总用水量 70 %的情况下 ,如何有效合理地控制农业用水就成为了制约沈阳市经济发展的关键因素。从国外的先进经验来看 ,大力发展节水灌溉是控制农业用水的有效途径。近几年 ,沈阳市也非常重视节水灌溉的发展 ,从统计数字来看 ,本市目前已发展节水灌溉面积 1 0万hm2 。但从已建的节水工程来看 ,普遍存在以下两方面问题 :1 1　盲目投资 ,对项目可行性分析不足以往的节水灌溉项目往往注重形象工程 ,长官意识严重 ,而对不同地区的…     

灌区灌溉用水管理决策支持系统总体设计

在分析灌溉用水管理主要内容和决策流程以及确定的系统开发原则基础上,提出了具有系统结构合理、软件设计先进、实用性强、扩充性能好、适应实时决策要求的灌溉用水管理决策支持系统总体设计方案以数据库和知识库作为信息基础,以模型库作为管理决策的重要支撑手段,针对以上三库相互之间在概念和结构上存在交叉,在运行中存在数据流交换的特点,建立总控系统。通过多组件之间的接口集成整个决策支持系统,实现信息查询、灌水预报、水量分配等功能。该系统界面友好、直观,操作灵活、方便。     

Integrated Water Resources Management in Polrud Irrigation System

Water is needed in all aspects of life and is vital to its social, economical and environmental dimensions. Having a key role in sustainable development, water management requires an integrated approach. Irrigation Water shortage promotes the development of innovative management and supply enhancement models. Effective water management requires a comprehensive consideration of all related aspects, e.g., technical, social, environmental, institutional, political and financial. Then the conventional methods of cost-benefit analysis and single-objective models have changed to multi-objective models. The rising of population in Iran puts significant pressure on authorities and infrastructures to provide water. Without improvement in water management, Irrigation demand will continue to increase, water supplies will diminish and the population pressure will decay infrastructure. This paper describes compromise programming to solve multi-criteria decision making in irrigation planning for Polrud project in the North of Iran. The important objectives of project are: regulation of reliable water at the demand time, improving rice and tea production, domestic water supply, environmental needs as well as reducing social conflicts. After execution of the model, results show the optimum decision for crops pattern and extents of allocated water to each area. This study is a successful implementation of IWRM in irrigation planning.     

水库灌区抽水站水泵选型设计

在抽水站设计中,需对大量的基础数据处理后才能进行工况点的计算。此文试着在水泵选型设计计算时,对水泵工况点参数进行拟定和工况点计算的程序化,从而真正地利用计算机减少设计人员的工作量。     

Sustainable Water Supply and Demand Management in Semi-arid Regions: Optimizing Water Resources Allocation Based on RCPs Scenarios

Climate as one of the key factors in water resources management affects the amount of water in the hydrological cycle, which subsequently impacts the level of water availability. Considering the challenges that the South Alborz Region, Iran is currently facing in supplying water for various consumers; in this study, the climate change adaptation scenarios are investigated for sustainable water supply and demand. This study uses a procedure in which five different adaptation approaches, under RCPs scenarios, were established using the WEAP model to assess the impacts of various adaptation strategies on increasing the balance between water supply and demand over current and 2020s accounts. The findings suggest an imbalance between supply and demand in the current situation with the greatest imbalance in domestic use while the minimum in the industrial sector. The results of assessing adaptive scenarios show that various scenarios have different effects on balancing the water supply and demand by different consumers; on the other hand, the scenarios that directly affect domestic water demand have the greatest effect on minimizing the gap between supply and demand in the region; therefore, the options for decreasing the population demand along with diminishing the losses in the domestic water distribution network are the most effective alternatives for balancing supply and demand under all of the climate scenarios. The findings of this research indicate that adaptive management with the focus on restricting demand helps actively management of water resources in the regions with scarce water resources.

     

用水户参与式灌溉管理模式初探

实现用水户参与式管理是进行灌区体制改革的重要途径。文章论述了用水户参与式灌溉管理的内涵、要求和基本模式。在回顾国外其他国家发展灌区参与式管理的历史经验基础上,文章重点介绍了湖南省岳阳市铁山灌区用水户参与式管理的基本情况和管理成效,同时,文章根据实施用水户参与式灌溉管理模式的实践提出了相关的建议和看法。     

加强水利工程水费征收及管理

本文通过对有关政策及征收术费与解决农村负担的关系的分析,说明征收水利工程术费的重要性。