共查询到20条相似文献，搜索用时 15 毫秒
1.
Dimitrios Gotsis Mike Spiliotis Spyros Giakoumakis 《Irrigation and Drainage Systems》2011,25(4):385-394
Water management for irrigation in areas with high water scarcity includes not only domestic wastewater treatment but also practices for the reuse of drainage water during the irrigation period. The main problem that concerns the reuse of drainage water for irrigation is the accumulation of salts due to the effluents existing in the soil. In this paper an optimization technique is proposed for the management of drainage water that uses, in combination, a soil-water-plant model (SWAP) and a mixed 0-1 linear programming method. The optimization routine was applied to the irrigation network of Alfeios River in Western Greece, an area that is characterized by high precipitation imbalances between winter and summer months. 相似文献
2.
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
3.
《Agricultural Systems》1998,58(4):529-554
An integrated approach to reservoir, irrigation, and cropping management which links four different models—a hydrologic model (PRMS), a crop growth simulation model (EPIC), an economic model based on linear programming, and a dynamic programming model—is developed and demonstrated. The demonstration is based on an irrigation district located in a subhumid climate with an irrigation reservoir large enough for over-year storage. The model is used to make repeated simulations for various planning horizons. Two different types of results are presented. The first provides the probability that each of the various farm plans (land/crop/water allocation) will be chosen as the optimum in the first year of the planning horizon. The second approach provides probability distributions of accumulated revenues over a chosen length of planning horizon. Each distribution is associated with an initial reservoir level and a particular farm plan in the first year of the planning horizon. The consequence of selecting certain farm plans at the beginning of a specified planning horizon is therefore quantified in a probabilistic way. Based on families of probability–revenue curves, an irrigation manager can simultaneously evaluate crop, irrigation, and reservoir management options. 相似文献
4.
《Agricultural Water Management》2002,57(3):207-221
The Samanalawewa and Udawalawe reservoirs were built to harness the hydro-energy and irrigation potentials of the Walawe river in Sri Lanka. The recently completed Samanalawewa reservoir primarily generates hydropower while the Udawalawe reservoir, which was built in the 1960s, supplies water mainly for irrigation. With the addition of the Samanalawewa reservoir, located upstream of the Udawalawe reservoir, the Government of Sri Lanka is planning to increase the irrigated area of the Udawalawe reservoir. The Samanalawewa reservoir is expected to act as an additional storage for irrigation water supply. A study was carried out to investigate the operational behavior of these two reservoirs. The model used in the study is based on stochastic dynamic programming (SDP) and simulation techniques. Since, the direct application of SDP for two reservoirs is limited by the dimensionality of the problem, a sequential decomposition method is employed in the model. The algorithm employed breaks down the system into single-reservoir subsystems and subsequently, each subsystem’s operation is individually optimized using a SDP based optimization model and then simulated using a reservoir operation simulation model. The results indicate the usefulness of optimization techniques in planning reservoirs and deriving operational policies for them. The inclusion of the Samanalawewa reservoir reduces the irrigation water supply deficits at the Udawalawe reservoir. 相似文献
5.
利用动态规划法确定水库最优灌溉面积 总被引：1，自引：0，他引：1
王博 《中国农村水利水电》1997,(11):11-13
利用动态规划法对供水水库进行长系列优化调度，建立了一维或多维并联供水水库优化调度数学模型，编制了通用计算机程序，通过点绘水库灌溉面积与供水保证率、灌溉面积与缺水率曲线，在给定灌溉保证率下通过查曲线即可确定水训最优灌溉面积。 相似文献
6.
《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
7.
Shigeya Maeda Tatsuya Nagamochi Toshihiko Kawachi Junichiro Takeuchi 《Irrigation and Drainage Systems》2011,25(2):81-96
A multiobjective optimization model has been presented for allocating irrigation waters in a rice paddy area. Water-saving
practices conducted on the field-plot basis are considered and expressed in the optimal water allocation problem in the regional
scale. Irrigation water allocated to the blocks of paddy fields is divided into two components of a basic amount and a safety
margin in order to mitigate the effect of hydrological and hydraulic uncertainties on the study area. Four competing management
objectives with regard to total rice yield, total water-saving cost, equity of water allocation, and safety of water supply
are defined in the linear programming formulation so that noninferior solutions can be procured which are informative and
persuasive in decision-making. Applicability of the optimization model is examined using water allocation problems for a hypothetical
irrigation system. It is demonstrated that the optimization model can provide satisficing solutions where the four objectives
are harmonized under substantial variations of total water supply to the irrigation system. 相似文献
8.
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
9.
考虑不同层次利益主体的灌溉水资源优化配置 总被引：3，自引：0，他引：3
针对灌溉水资源优化配置中存在的非线性和不确定性等特点,同时考虑灌区不同层次决策主体利益,分别构建考虑上层管理者利益的区间线性分式规划(ILFP)模型以获得最大的灌溉水生产力和考虑下层农民利益的区间二次规划(IQP)模型以获得最大的产量。在此基础上,将灌区上、下层利益主体作为整体,构建线性分式二次双层规划(LFQBP)模型,以协调灌区不同层次决策主体利益,促进灌区可持续发展。将所构建模型应用于盈科灌区的粮食作物配水中。通过配水结果的比较来分析各模型的性质,结果表明ILFP模型和LFQBP模型更适用于干旱地区。所构建模型从不同角度反映灌溉配水的实际问题,其优化结果有助于灌区管理者权衡各层决策主体间的利益。 相似文献
10.
Optimization model of an irrigation reservoir for water allocation and crop planning under various weather conditions 总被引：1，自引：0，他引：1
This paper develops a non-linear programming optimization model with an integrated soil water balance, to determine the optimal
reservoir release policies, the irrigation allocation to multiple crops and the optimal cropping pattern in irrigated agriculture.
Decision variables are the cultivated area and the water allocated to each crop. The objective function of the model maximizes
the total farm income, which is based on crop–water production functions, production cost and crop prices. The proposed model
is solved using the simulated annealing (SA) global optimization stochastic search algorithm in combination with the stochastic
gradient descent algorithm. The rainfall, evapotranspiration and inflow are considered to be stochastic and the model is run
for expected values of the above parameters corresponding to different probability of exceedence. By combining various probability
levels of rainfall, evapotranspiration and inflow, four weather conditions are distinguished. The model takes into account
an irrigation time interval in each growth stage and gives the optimal distribution of area, the water to each crop and the
total farm income. The outputs of this model were compared with the results obtained from the model in which the only decision
variables are cultivated areas. The model was applied on data from a planned reservoir on the Havrias River in Northern Greece,
is sufficiently general and has great potential to be applicable as a decision support tool for cropping patterns of an irrigated
area and irrigation scheduling. 相似文献
11.
Optimal on-farm irrigation scheduling with a seasonal water limit using simulated annealing 总被引：1，自引：0，他引：1
As water resources are limited and the demand for agricultural products increases, it becomes increasingly important to use irrigation water optimally. At a farm scale, farmer's have a particularly strong incentive to optimize their irrigation water use when the volume of water available over a season is production limiting. In this situation, a farmer's goal is to maximize farm profit, by adjusting when and where irrigation water is used. However, making the very best decisions about when and where to irrigate is not easy, since these daily decisions require consideration of the entire remaining irrigation season. Future rainfall uncertainty further complicates decisions on when and which crops should be subjected to water stress. This paper presents an innovative on-farm irrigation scheduling decision support method called the Canterbury irrigation scheduler (CIS) that is suitable when seasonal water availability is limited. Previous optimal scheduling methods generally use stochastic dynamic programming, which requires over-simplistic plant models, limiting their practical usefulness. The CIS method improves on previous methods because it accommodates realistic plant models. Future farm profit (the objective function) is calculated using a time-series simulation model of the farm. Different irrigation management strategies are tested using the farm simulation model. The irrigation strategies are defined by a set of decision variables, and the decision variables are optimized using simulated annealing. The result of this optimization is an irrigation strategy that maximizes the expected future farm profit. This process is repeated several times during the irrigation season using the CIS method, and the optimal irrigation strategy is modified and improved using updated climate and soil moisture information. The ability of the CIS method to produce near optimal decisions was demonstrated by a comparison to previous stochastic dynamic programming schedulers. A second case study shows the CIS method can incorporate more realistic farm models than is possible when using stochastic dynamic programming. This case study used the FarmWi$e/APSIM model developed by CSIRO, Australia. Results show that when seasonal water limit is the primary constraint on water availability, the CIS could increase pasture yield revenue in Canterbury (New Zealand) in the order of 10%, compared with scheduling irrigation using current state of the art scheduling practice. 相似文献
12.
A model for optimal allocation of water from a single-purpose reservoir to an irrigation project with pre-determined multiple cropping patterns was developed. The model consisted of two modules: (I) the intra-seasonal allocation model (non-linear programming) which is used for allocation of water among different crops for a definite combination of state variables (inflow class, rainfall class, reservoir storage classes at the beginning and at the end of the season) for the non-dormant season to maximize total farm income; and (II) the seasonal allocation model (stochastic-dynamic programming) which is used for the convergent operating policy over seasons for optimal expected farm income over a year. The model was applied to Ardak reservoir dam (I.R. Iran) in an arid region. Low river inflow in the dormant season at the study area could not admit the reservoir class changes for specific combinations of state variables, and therefore resulted in a non-usable result. Imposing a fictitious positive relative net benefit for all possible combinations of reservoir class changes eliminated this problem. It was also shown that rainfall did not play a marked role in the study area, which is an arid region, and its stochastic nature can be removed from the model. 相似文献
13.
《Agricultural Water Management》2005,73(3):193-221
A mathematical model is developed to arrive at an optimal conjunctive use policy for irrigation of multiple crops in a reservoir-canal–aquifer system. The integration of the reservoir operation for canal release, ground water pumping and crop water allocations during different periods of crop season (intraseasonal periods) is achieved through the objective of maximizing the sum of relative yields of crops over a year considering three sets of constraints: mass balance at the reservoir, soil moisture balance for individual crops, and governing equations for ground water flow. The conjunctive use model is formulated with these constraints linked together by appropriate additional constraints as a deterministic linear programming model. A two-dimensional isotropic, homogeneous unconfined aquifer is considered for modeling. The aquifer response is modeled through the use of a finite element ground water model. A conjunctive use policy is defined by specifying the ratio of the annual allocation of surface water to that of ground water pumping at the crop level for the entire irrigated area. A conjunctive use policy is termed stable when the policy results in a negligible change in the ground water storage over a normal year. The applicability of the model is demonstrated through a case study of an existing reservoir command area in Chitradurga district, Karnataka State, India. 相似文献
14.
An inexact two-stage water management model for planning agricultural irrigation under uncertainty 总被引：2，自引：0，他引：2
In this study, an inexact two-stage water management (ITWM) model is developed for planning agricultural irrigation in the Zhangweinan River Basin, China. The ITWM model is derived from the incorporation of interval-parameter programming (IPP) within a two-stage stochastic programming (TSP) framework. It can reflect not only uncertainties expressed as probability distributions but also interval numbers. Moreover, it can provide an effective linkage between conflicting economic benefits and the associated penalties attributed to the violation of the predefined policies. Four decision scenarios associated with different water-resources management policies are examined. Targeted incomes, recourse costs, and net system benefits under different scenarios are analyzed, which indicates that different policies for agricultural irrigation targets correspond to different water shortages and surplus, and thus lead to varied system benefit and system-failure risk. The results are valuable for supporting the adjustment or justification of the existing irrigation patterns and identify a desired water-allocation plan for agricultural irrigation under uncertainty. 相似文献
15.
16.
山东禹城引黄灌区非充分灌溉配水模型 总被引：3，自引：0，他引：3
为了制定有多种作物且灌溉水源为动态变化的灌区的配水计划，提出了由充分灌溉和非充分灌溉2级模型组成的配水模型。其中非充分灌溉配水模型包括优化模型和模拟模型2部分，优化模型的方案具有较好的经济效益，而模拟模型的方案便于实施。模型中联合运用引黄水和地下水，可减少因黄河缺水对农业造成的重大损失。在此基础上编制的山东禹城灌溉配水管理决策支持系统界面友好，实用性强，基本上可灌溉灌区的管理需要。 相似文献
17.
Raul P. Lejano 《Irrigation and Drainage Systems》2006,20(1):125-137
Branched distribution systems are found in a large number of situations, including rural irrigation, reclaimed water distribution,
and effluent disposal. Much research has been developed around optimizing pipeline design assuming a predetermined geographical
layout of the distribution system. There has been less work done, however, on the problem of optimizing the configuration
of the network itself, which is a particularly crucial issue in lower-income areas where the need for cost-effective irrigation
systems is greatest. Generally, engineers develop the basic layout through experience and sheer intuition. In this paper,
a method is developed for determining an optimal layout for a branched distribution system given only the spatial distribution
of potential customers and their respective demands. The technique utilizes a mixed integer linear programming (MILP) algorithm
to optimize an empirically derived objective function. The method is tailored for practical application and allows the decision
maker to simultaneously solve for the optimal customer/user base and pipeline layout. The method is illustrated with a simple
example. 相似文献
18.
灌区灌溉用水时空优化配置方法 总被引：1，自引：0，他引：1
将传统的灌溉水量在作物间的优化分配模型和建立的渠系工作制度多目标优化模型与地理信息系统相集成,提出了基于空间决策支持系统的灌区灌溉用水优化配置的新方法.综合考虑了灌区内作物、土壤、气象站点、渠系布置的空间差异、年季间气象以及作物不同生育阶段对应参数的时间差异.与传统优化方法相比,该方法可根据管理者对优化精度的要求,灵活选择优化尺度,同时,简化了求解时空优化配水问题的繁琐程度,结果表现形式更加丰富.在此基础上建立的空间决策支持系统界面友好,运行效率高,可移植性和通用性强.经实例验证,优化后的配水方案与原配水方案相比较,灌溉总用水量减少296％,产量增加243％,水分生产率提高05 kg／m3,灌溉净效益增加168％.优化后配水方案具有将有限的水资源向经济价值较高作物转移的趋势.该方法为灌区灌溉用水优化配置提供了新思路. 相似文献
19.
This paper introduces a combined modelling approach using a simple water budget model (THC-model) and a 3D reservoir sedimentation
model (MOHID Water) to adapt reservoir operation and visualise their effects on the sediment deposition. By this, an effective
combined sediment-water management can be identified under semi-arid conditions for dry, median and wet years. Results are
presented for the reservoirs of the Tuyamuyun Hydro-Complex (THC), which is located in the lower Amu Darya River. The determination
of the actual and usable reservoir storage volume shows that siltation will significantly adversely affect the ability of
the in-stream Channel Reservoir to regulate seasonal demand for both irrigation and municipal water supply. However, modelling
scenarios results confirm the effectiveness of adapted operation rules for the THC reservoirs and show that the operation
of large dams could be modified according to a combined sediment-water management. The experience gained during this study
emphasizes the fact that the concept of a combined reservoir management of sediments as well as water can be an efficient
measure to improve the sustainable long-term use of reservoirs and to contribute towards a safe water supply in water crisis
regions. 相似文献