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1.
A linear programming (LP) based optimization model and a simulation model are developed and applied in a typical diversion type irrigation system for land and water allocation during the dry season. Optimum cropping patterns for different management strategies are obtained by the LP model for different irrigation efficiencies and water availability scenarios. The simulation model yields the risk-related irrigation system performance measures (i.e. reliability, resiliency and vulnerability) for the management policies defined by the optimization model. The alternative strategies are evaluated in terms of all performance criteria (i.e. net economic benefit, equity and reliability) simultaneously through a trade-off analysis using a multi-criteria decision making method (compromise programming). For the case study of the Kankai irrigation system in Nepal, with equal preference to the objectives, a management strategy with equal share of water among the project subareas appears to be the most satisfactory alternative under water shortage conditions. The existing water allocation policy is not economically efficient. Deficit irrigation in Early paddy appears attractive under favorable hydrologic scenario, particularly if accompanied by measures to improve existing irrigation system efficiency. 相似文献
2.
Joséphine Semaan Guillermo Flichman Alessandra Scardigno Pasquale Steduto 《Agricultural Systems》2007
Nitrate leaching is one of the many forms of environmental pollution resulting from irrigation and intensive agriculture. In this work, a method of combining an agronomic simulation model (EPIC) and a mathematical multi-objective programming model is used to analyse the effects of three agricultural policies on farmer’s revenue and nitrate leaching. An evaluation of the net social costs associated with the different policy measures is also given. The farmer’s behaviour in different policy scenarios was studied in terms of selected crops, irrigation technique and method, and adopted management practices with focus on farm management practices and water application efficiency. Irrigation water pricing, subsidies to adopt improved management levels, and taxation on the use of nitrogen fertilizer were examined. A trade-off emerges between the levels of nitrate leaching and net farmer’s revenue more pronounced for nitrogen tax policies than for water pricing. The results obtained indicate that nitrate leaching can be reduced by about 40% with an associated net social cost of 269 €/ha for the water pricing policy, 183 €/ha for the tax on fertilizer and 95 €/ha for subsidies to high efficiency management. 相似文献
3.
A hybrid fuzzy-stochastic water-management (FSWM) model is developed for agricultural sustainability under uncertainty, based on advancement of a multistage fuzzy-stochastic quadratic programming (MFSQP) approach. In MFSQP, uncertainties presented in terms of fuzziness and randomness can be incorporated within a multilayer scenario tree, such that revised decisions are permitted in each time period based on the realized values of the uncertain events. Moreover, fuzzy quadratic terms are used in the objective function to minimize the variation of satisfaction degrees among the constraints; it allows an increased flexibility in controlling the system risk in the optimization process. Results of the case study indicate that useful solutions for the planning of agricultural water management have been obtained. In the FSWM model, a number of policies for agricultural water supply are conducted. The results obtained can help decision makers to identify desired water-allocation schemes for agricultural sustainability under uncertainty, particularly when limited water resources are available for multiple competing users. 相似文献
4.
An integrated hydro-economic modelling framework to evaluate water allocation strategies II: Scenario assessment 总被引：2，自引：0，他引：2
Biju George Hector MalanoBrian Davidson Petra HellegersLuna Bharati Sylvain Massuel 《Agricultural Water Management》2011,98(5):747-758
In this paper the results of an assessment of the hydrological and economic implications of reallocating water in the Musi sub-basin, a catchment within the Krishna Basin in India, are reported. Policy makers identified a number of different but plausible scenarios that could apply in the sub-basin, involving; supplying additional urban demand from agricultural allocations of water, implementing a number of demand management strategies, changing the timing of releases for hydropower generation, changing the crops grown under irrigation, reducing existing stream flows and allowing for more environmental flows. The framework chosen to undertake this assessment was a simulation model that measures and compares the economic values of water allocation scenarios determined from a water allocation model that accounts for supplies of groundwater and surface water across a number of regions and over a variety of uses. Policy makers are provided with the range of measures on the security of the supply of water and the social costs and benefits of reallocating water between sectors and across regions within the sub-basin. Taking water from agriculture to supply urban users has a greater impact on irrigation supplies during dry years. It was also found that changing the allocation of water between sectors, by taking it away from agriculture had a large positive economic impact on the urban sector. Yet the costs involved in undertaking such a strategy results in a significant loss in the net present value of the scheme. Stream flow reductions, if significantly large (at around 20%), were found to have a large physical and economic impact on the agricultural sector. Implementing water saving strategies in Hyderabad was found to be more cost effective than taking water from agriculture, if rainwater tanks are used to achieve this. Changing the timing of hydropower flows resulted in best meeting of irrigation demand in NSLC and NSRC. Under this scenario, the crops grown under irrigation were found to have a significant economic impact on the sub-basin, but not as large as farmers undertaking crop diversification strategies, ones which result in farmers growing less rice. The security of supplying water to different agricultural zones has significantly improved under this scenario. Finally, releasing water for environmental purposes was found to have only a minor impact on the agricultural sector. 相似文献
5.
以黑龙江省和平灌区为例,构建基于多目标模糊规划的灌区多水源优化配置模型,该模型能够在提高农业灌溉用水净效益的同时有效减少农业灌溉水量,促进和平灌区多水源高效配置。采用具有非线性隶属度函数的模糊多目标规划求解模型,得到不同流量不同水源下的最优配水方案。结果表明:不同流量水平下水稻不同生育阶段均存在缺水现象,低流量下需从柳河水库引入外调水才能保证水稻的最小需水量。为保证灌区整体效益,按照引水工程、提水工程、井灌工程的先后顺序进行配水,并得到多目标配水模型在不同情景下的运行稳定情况。该模型可以高效地进行灌区多水源在作物各生育阶段的优化配置。 相似文献
6.
《Agricultural Systems》2001,68(3):233-252
This paper introduces a linear programming optimization model for analyzing inter-seasonal allocation of irrigation water in quantities and qualities and their impact on agricultural production and income. The SAWAS model is a developed version of the Agricultural Sub-Model (AGSM). In this research, we stress water scarcity as a problem that arises when water is not found in proper quantity and quality at the appropriate place and time. The model is designed to serve as a decision-making tool for planners of agricultural production on both the district and the regional level. It generates an optimal mix of water-demanding activities that maximizes the net agricultural income of the districts and gives the water demands under various prices. It also provides the planner with tools to carry out ‘what-if’ experiments and to generate optimal water demand curves. A principal feature of SAWAS is the use of demand and the benefits from water together with costs and optimization within the agricultural sector to specify the optimal usage of different water qualities. Hence the agricultural planner can use the outputs of SAWAS in order to bridge the gap between the limited water resources and the increased agricultural production in an area that suffers from severe water scarcity. The paper applies the SAWAS model to the Jordan Valley in Jordan. 相似文献
7.
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. 相似文献
8.
Due to urban growth, some agricultural lands have been replaced by residential, municipal, and industrial areas. In some cases the remaining agricultural land will not have enough water because of transfers from agriculture to M&I (municipal and industrial) users. Therefore, in many places, especially in arid and semi-arid regions, the use of treated wastewater as a reliable source of irrigation water has already been, or will be, considered in the future. Due to its unique characteristics, this new resource has many challenges that cannot be ignored, such as health issues, water quality, and long- and short-term effects on soils and crops. The study described herein considered the development of a new GIS-based model for planning and managing the reuse of treated wastewater for the irrigation of agricultural and green lands, considering various factors such as population and urban growth. The model is composed of several different modules, including an urban growth model. These modules are designed to help in the decision-making process for allocations of water resources to agricultural areas, considering factors such as crop types, crop pattern, water salinity, soil characteristics, pumping and conveyance costs, and also by comparing different management scenarios. Appropriate crops that can be grown with a specific water salinity and soil characteristics, proper water resources for each farm (according to pumping and conveyance costs, and analysis of water demand, and water supply) can be determined through the application of this model. The model can also rank agricultural areas and open spaces in and near an urban area according to their suitability for irrigated agriculture. 相似文献
9.
The government of Zimbabwe uses agricultural development as one of the ways to stimulate economic growth. Agriculture in Zimbabwe is characterized by a dual agrarian system comprising the large scale commercial sector and the smallholder communal sector. The communal sector, 47 percent of the country, supports more than 70 percent of the population. One strategy used to improve agricultural performance is the development of agricultural infrastructure. Of the 117, 830 ha developed for irrigation only slightly more than 6 percent is in the communal (smallholder) sector. The smallholder irrigation systems are managed under four different systems, namely the government-managed Agritex, farmer-managed community, the informal bani (dambo) managed by farmers and the ARDA outgrowers managed jointly by a parastatal and farmers. This paper evaluates the benefits and costs associated with these different management systems. Benefit-cost ratios are computed for each system. The bani system achieves higher benefit-cost ratios than the community, which achieves higher ratios than the Agritex management system. This indicates that the government should consider using the community system for developing the potential 93,000 ha of communal smallholder irrigation systems. It should also seriously consider the bani system as an alternative development strategy. 相似文献
10.
Temporary water trading is an established and growing phenomenon in the Australian irrigation sector. However, decision support and planning tools that incorporate economic and biophysical factors associated with temporary water trading are lacking. In this paper the integration of an economic trading model with a hydrologic water allocation model is discussed. The integrated model is used to estimate the impacts of temporary water trading and physical water transfers. The model can incorporate economic and biophysical drivers of water trading. The economic model incorporates the key trade drivers of commodity prices, seasonal water allocations and irrigation deliveries. The hydrologic model is based on the Resource Allocation Model (REALM) framework, which facilitates hydrologic network simulation modelling. It incorporates water delivery system properties and operating rules for the main irrigation and urban centres in a study area.The proposed integration method has been applied to a case study area in northern Victoria, Australia. Simulations were conducted for wet and dry spells, a range of commodity prices and different irrigation distribution system configurations. Some example analyses of scenarios incorporating water trading were undertaken. From these analyses potential bottlenecks to trade that constrain the economic benefits from temporary water trading were identified. Furthermore, it was found that in certain areas of the system, trading can make impacts of long drought spells worse for water users, e.g. irrigators. Thus, the integrated model can be used to quantify short-term and long-term third party impacts arising from temporary water trading. These findings also highlight the need to link “paper trades” (estimated by economic models) to physical water transfers (estimated by biophysical models). 相似文献
11.
Lap Doc Tran Steven SchilizziMorteza Chalak Ross Kingwell 《Agricultural Water Management》2011,101(1):42-51
Choosing the appropriate reservoir water management strategy can be difficult when the water has multiple uses. This study examines this problem for reservoir managers where water use involves irrigation and fisheries. A stochastic dynamic programming (SDP) model is developed to facilitate reservoir management, using a case study illustration for southern Vietnam. The model includes the response of rice and fish yields to key factors including reservoir water levels, the timing and quantity of water release, and climatic conditions. The model also accounts for variation in rainfall patterns, irrigation requirements, and the demand for low water levels during the fish harvest season. Three production scenarios are examined where the reservoir's water is used for: only producing rice (scenario 1), only producing fish (scenario 2), and producing rice and fish (scenario 3). Key findings are: (1) for scenario 1, adequate water should be released to meet rice growing water requirements and residual water should be stored as a source of water in case of low rainfall, (2) for scenario 2, sufficient water needs to be released prior to the fish harvest to maximize this harvest; and (3) for scenario 3, water should be released prior to fish harvest, but sufficient water should remain to satisfy the water requirements of rice. When the reservoir is managed for joint production of rice and fish, net benefits are 6% greater than when the reservoir is managed solely for rice production. The SDP model developed in this paper could be adapted and applied to other multiple-use resources such as forests, river basins, and land. 相似文献
12.
《Agricultural Water Management》2002,52(2):139-154
It is important to promote efficient use of water through better management of water resources, for social and economical sustainability in arid and semi-arid areas, under the conditions of severe water shortage. Based on the developments in deficit irrigation research, a recurrence control model for regional optimal allocation of irrigation water resources, aiming at overall maximum efficiency, is presented, with decomposition-harmonization principles of large systems. The model consists of three levels (layers). The first level involves dynamic programming (DP) for optimization of crop irrigation scheduling. The second level deals with optimal allocation of water resources among various crops. The last level concerns optimal allocation of water resources among different sub-regions. As a test, this model was applied to the combined optimal allocation of multiple water resources (surface, ground and in-take from the Weihe river) of Yangling, a semi-arid region on the Loess Plateau, China. Exemplary computation showed that not only are the results rational, but the method can also effectively overcome possible “dimensional obstacles” in dynamic programming of multiple dimensions. Furthermore, each sub-model is relatively independent by using various optimization methods. The model represents a new approach for improving irrigation efficiency, implementing water-saving irrigation, and solving the problem of water shortage in the region studied. The model can be extended in arid and semi-arid areas for better water management. 相似文献
13.
中国节水灌溉装备与技术发展展望 总被引：1，自引：0，他引：1
分别从灌排设施、灌排管理体制和投资政策3个方面,回顾了中国灌溉排水70 a以来所取得的成就.随着灌溉面积增大,灌排设施极大提高了中国粮食产量和农业生产能力;灌排管理体制发生巨大变化,由农民集体管理为主转化为骨干工程国家事业单位管理为主,促进了灌排工程快速发展和良性运行;投资政策有效地服务了水利基本建设.但目前中国依旧存在灌溉用水利用率较低、水肥一体化灌溉农田占比较低和灌溉系统信息化程度较低等问题,与高质量的农业生产发展还有很大的距离.结合国家粮食与生态保障的战略需求,分别从大中型灌区节水改造、水肥一体化节水灌溉装备与技术和喷滴灌、管道输水灌溉和泵站改造方面,提出了中国节水灌溉装备与技术的未来机遇和挑战.为了促进中国节水灌溉行业发展,加强灌排装备的理论研究和自主创新,发展高效、节能和环保的技术和产品,提高产业信息化、智能化和网络化,是实现农业现代化生产建设的必然趋势. 相似文献
14.
The benefits of improved irrigation efficiency on production and income in rice-based irrigation systems is analyzed using a combination of simulation and structural model estimation techniques for five diversion irrigation systems in the Philippines. The results show that increased efficiencies generate substantial production and income benefits. With the limitations on new system development, designing and enforcing appropriate real-time water resource management policies to capture high potential benefits of improved irrigation efficiency should be an increasingly high priority for policy-makers. 相似文献
15.
A fertile discussion is developing in the EU regarding the application of the Water Framework Directive (60/2000) (WFD), the legislative act that provides the framework for water regulation in Europe and emphasises the role of economic instruments in water policy. The objective of this paper is to provide an evaluation of different instruments designed to deal with the management of water for agriculture, in the perspective of WFD implementation and agricultural price scenarios. The paper focuses on the regulation of mixed source unmetered water and carries out a comparison of flat rate versus differentiated contracts as the policy instrument. The analysis is based on a combination of linear programming and a Principal-Agent model. The empirical model is applied in an agricultural area of Northern Italy. The results show the feasibility of incentive-oriented policy instruments, even in the less sophisticated form of flat rate area payments. They also show the relevance of agricultural market scenarios and policy scenarios in the design of the optimal policy instruments. The adoption of such instruments, however, could require a revision of the role of different institutions involved in water management. 相似文献
16.
《Agricultural Water Management》1996,31(3):237-251
Appropriate information is a pre-requisite for improving the management of irrigation systems. An effort was made to establish the information system required in management of an irrigation unit at the tertiary level (Ban-Rom Water Users' Association, Thailand). A computerized database was developed for use on a microcomputer using the combination of a commercial database management system and a linear programming optimizer. This information system was simple to operate through the use of menu-driven procedures.This database system can replace the previous manual system for data recording and retrieval of information related to the management of agricultural organizations and related irrigation aspects. The optimal solution for cropping pattern and water allocation obtained from the system can be used as a guideline in pre-season planning for irrigation delivery and crop selection. 相似文献
17.
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. 相似文献
18.
A robust modeling approach for regional water management under multiple uncertainties 总被引：1，自引：0，他引：1
In regional water management systems, various uncertainties may be derived from random feature of resource conditions and natural processes, errors in estimated modeling parameters, as well as imprecision or fuzziness human-induced. This leads to difficulties in formulating and solving the resulting regional water management problems. In this study, a robust multistage interval-stochastic programming (RISP) method is developed for dealing with vague and random information in regional water management systems. The decision variables are useful for justifying and/or adjusting the decision schemes for agricultural activities through the incorporation of their implicit knowledge on regional water management. Different policies for agricultural water supply have been analyzed. The results can help to identify desired water-allocation schemes for agricultural sustainable development that the prerequisite water demand for supporting crops’ survival can be guaranteed when the water resource is scarce. 相似文献
19.
One of the methods for increasing productivity of water consumed in agriculture is by improved water supply management. This
paper presents results from an optimization study of the Malampuzha irrigation project of the Bharathapuzha river basin of
Kerala in India. The objective of this study is to determine whether significant improvements might be realized from optimization
of operation of the reservoir system. To do this a mixed integer linear programming (MILP) model is developed and five different
management strategies are tested. The result indicates that a management strategy with deficit irrigation by supplying less
water in non-critical growth period and maximum water during stress sensitive periods is a best viable solution for better
performance. A MILP model, rather than a linear programming (LP) model, is used to ensure that the reservoir does not spill
before reaching its capacity. 相似文献
20.
应用线性规划数学模型对河南省韩董庄引黄灌区作物种植布局和引黄水及地下水联合运用进行了分析.对作物种植规划,作物灌溉增产效益,引黄工程及井灌工程运行费用,引黄供水能力等参数进行了详细分析计算,建立了灌溉水资源优化调配模型,应用计算机求解提出了灌区作物种植优化布局方案及水资源优化调配方案,并给出了各种灌溉方案条件下的灌溉效益,所得结果对灌区规划与发展具有重要参考价值. 相似文献