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1.
《Agricultural Water Management》2001,48(2):117-132
In this paper, the proposed optimisation model is applied to optimise water management in the Bembézar system, a small hydrological basin belonging to the Guadalquivir River basin in southern Spain that supplies water to the Bembézar River Irrigation District.In order to apply the model, the irrigation methods and performance in the irrigation district have been analysed through a set of field irrigation evaluations. Cropping patterns, crop productivity and other relevant agronomic and economic data have been collected.The influence of irrigation uniformity and the type of distribution of irrigation water on the crop yields, as well as the relationship between crop yields and irrigation scheduling have been analysed using the proposed model.A deterministic analysis has been carried out in the irrigation district in order to compare optimum water and cropping patterns management with actual ones.In order to account for the randomness of both climatic and water availability variables, a stochastic data generation has been carried out which considers the correlation between these hydrological series. The system is then analysed in a stochastic environment. Several simulations of the optimisation process have been carried out using generated data on climatic and water availability variables.The result of this analysis demonstrates that when only the satisfaction of the internal demands is considered, high quantities of water are allocated to the irrigation districts resulting in low economic benefits per unit of water used and lower irrigation efficiency. This situation has been compared with the solution provided by the hypothesis of a proposed water market in which it is possible to transfer part of the water of the system to other alternative uses at a fixed price. In this second hypothesis, water consumption in the irrigation districts was reduced. 相似文献
2.
Several parameters that measure the irrigation performance were analyzed for their relation to surface-irrigation design variables and yield. Application efficiency (AE), requirement efficiency (RE), uniformity coefficient (UC), deficit efficiency distribution (DED) and requirement distribution efficiency (RDE) were examined with respect to surface irrigation design variables (inflow discharge, length of the run, and time of irrigation cutoff). RE, RDE and UC were correlated with relative yield. Surface-irrigation models were used to simulate furrow and border irrigation and to determine the value of the performance irrigation parameters. A linear crop-water-production function was used to estimate yield. The RE and RDE were very well correlated with the design variables in border and furrow irrigation, and they were the parameters best correlated with the relative yield. The UC was not correlated with the design variables and gave a poor correlation with the relative yield. The AE was well correlated with the design variables. 相似文献
3.
《Agricultural Water Management》1996,29(2):129-145
Microtopography has long been recognized as one of the key variables in level-basin irrigation performance, although little effort has been devoted to establish its relevance. In this work, experimental data are used to quantify the influence of microtopography on irrigation performance. An irrigation evaluation was performed on a small level-basin (256 m2) LASER levelled to zero slope. Irrigation depth was gravimetrically measured and estimated at the 49 nodes of a regular network. Data from the irrigation evaluation and a two-dimensional flat-bed model were used to estimate irrigation depth. Irrigation times, soil surface elevation and distance to the inlet were estimated at the same nodes, and a correlation matrix was computed. Results showed that soil surface elevation was highly and significantly correlated with the times of advance (0.72571), recession ( −0.81571) and opportunity ( −0.85271), and with the measured irrigation depth ( −0.58371). Distribution uniformity using soil water measurements was 71.0%. Estimates from the irrigation evaluation and the two-dimensional model were 85.3% and 94.9%, respectively. The irrigation evaluation procedure could explain 3071% of the measured variability in irrigation depth. A large part of the unexplained variance in measured irrigation depth seems to be due to the spatial variation of infiltration properties. Predictions by the two-dimensional model were not significantly related to the measured values. A simple method was devised to estimate microtopography-adjusted irrigation performance from the results of a flat bed model and the standard deviation of elevation. Microtopography can have an important effect on level-basin irrigation performance. Models not considering this variable may incur large errors when simulating irrigation performance. 相似文献
4.
L. Mateos 《Irrigation Science》2006,25(1):75-83
Standard evaluation procedures, based on field measurements and statistical, hydraulic models, have been developed for assessing irrigation systems performance. However, given the diverse nature of the irrigation methods, it is not possible to use a unique evaluation procedure. Ideally, variables would be measured at every point throughout the field under study, but that is clearly impractical. Instead, measurements are taken of selected samples, or irrigation models are used to predict field-wide distributions of the variables. In this paper, irrigation models for trickle, sprinkler and furrow irrigation are used to assess how well the irrigation performance indicators generated by standard procedures match those generated by whole-field simulations. Six performance indicators were used: distribution uniformity, uniformity coefficient of Christiansen, application efficiency, deep percolation ratio, tail water ratio and requirement efficiency. The analysis was applied to systems typical of cotton crops in Southern Spain. The results show that the procedure used to determine performance indicators in trickle irrigation provides good estimates of the whole field performance. The procedure used in sprinkler irrigation is also acceptable, but yields variable results. Finally, the standard procedure used for furrow irrigation produces biased, highly variable results and overestimates distribution uniformity. 相似文献
5.
J. Mohan Reddy 《Irrigation Science》1994,15(2-3):123-136
The design problem of furrow irrigation systems considering runoff and drainage water quality was formulated as an optimization problem, with maximization of net benefits as the objective. A power advance function with an empirically derived relationship between the furrow irrigation design variables and relative crop yield were used in the formulation. The generalized geometric programming technique was used to solve for the optimal values for the design variables that maximized the net benefits from a furrow irrigation system. The optimal efficiency for which the system must be designed under a given set of soil, crop, and economic conditions is not known in advance. In the design, the application efficiency was not specified a priori. It was an output from the optimal design. The analysis suggested that it might not be economical to design surface irrigation systems to achieve a high application efficiency that is specified a priori. In the absence of environmental degradation problems from irrigation, it may sometimes be profitable to design surface irrigation systems to operate at less than the standard application efficiency (55%–90%) that is routinely used in the design. Formulation of the design problem as an optimization problem would yield the optimal application efficiency that would maximize the net benefits to the farmer under any given set of conditions. 相似文献
6.
M. S. Moran 《Irrigation Science》1994,15(1):35-44
Agriculture has long been promoted as a prime beneficiary of remotely sensed data and satellite data are now routinely used in crop production forecasts and for resource surveys. However the potential for using satellite data for irrigation management has not been realized. An experiment was conducted at the Maricopa Agricultural Center, Arizona, to test the feasibility of using satellite and aircraft data for crop monitoring and irrigation management. This experiment identified several shortcomings of present satellite systems with respect to providing timely information for irrigation management. On the other hand, a preliminary evaluation of aircraft data showed some potential for application to irrigation scheduling. A simple cost/benefit analysis suggested that profits could be achieved through the communal use of remotely sensed information from both satellites and aircraft in moderate-size irrigation districts. 相似文献
7.
In this study a simulation model for real-time irrigation scheduling of water deliveries at the tertiary and secondary canal levels of large irrigation systems has been developed. The model is responsive to current season changes in weather and other variables. The irrigation scheduling of the subsequent week is found out at the end of each week by updating the status of the system with real time data up to that week and then by solving the model for the new conditions. The model is based on water balance approach for lowland paddy and a soil moisture simulation approach for determining the irrigation requirements of upland crops. Expected rainfall at different probability levels during the irrigation season was used based on past rain fall data and Leaky law. The model was applied to an irrigation system in Thailand for determining the required irrigation deliveries. Result of the application indicate that the model can be used for determining water deliveries in a real-time basis. 相似文献
8.
9.
应用具有决策支持系统(DSS)功能的SEDAM模型模拟黄河下游簸箕李引黄灌区的灌溉需求与渠系输配水状况,利用节水多准则分析方法评价农田与输配水系统的改善方案。以田间实测的各类典型数据资料为基础,采用随机方法生成与田间和各级渠道相关的数据,产生用于多准则分析的属性数据和性能指标。根据不同水平的与农田及输配水系统相关的决策变量,设计了8种用于改善农田与输配水系统的模拟方案,通过模拟的需水量与现状供水量之间的对比以及模拟的各类效用值随时间变化的趋势,对模拟结果进行分析。结果表明,采用改善的农田与输配水系统运行方案可有效地减少渠系渗漏量,较好地控制农田渗漏损失,利用田间径流排水作为补灌水源,达到节水增产、改善农田生态环境的目的。 相似文献
10.
《Agricultural Water Management》2001,48(2):103-116
In this paper, an economic optimisation model for hydrologic planning in deficit irrigation systems is proposed. Irrigation water allocation between agricultural demands is carried out following an economic efficiency criterion with the aim of maximising the overall economic benefits obtained, allocating available water to each user as a function of the water’s profit margin. Water resources constraints in the system are considered. Aggregated economic functions for each irrigation district are generated optimising the water used for the cropping pattern. Stochastic nature of water availability and irrigation requirements have been taken into account.Due to the complexity of the system, the problem has been broken down into three independent optimisation sub-problems that perform hierarchically. Each of these sub models takes into account a different resolution level of the system: crop, irrigation district and the whole basin.The proposed model has been used in a subsequent paper to optimise water allocation planning in a small basin in southern Spain; the Bembézar system. 相似文献
11.
A mathematical model based on the complete hydrodynamic equations describing open-channel flow is developed for simulation of a complete irrigation in a surface irrigation system. An explicit two-step numerical scheme has been employed for the solution of the flow equations. The total infiltrated water depth at each location along the field is determined. From this intermediate result three performance parameters, expressing the merits of the irrigation as affected by the magnitude of each of the various independent physical or management variables involved in the process, are evaluated. Through an analysis of these effects the selection of the proper size or magnitude of a number of the major parameters becomes possible and thus an optimum combination of the main design or operation parameters in a surface irrigation system can be obtained. Two examples of the proposed technique are included as well as some typical graphs of standardized solution. 相似文献
12.
The manager of an irrigation project needs to know the irrigation time and depth so as to maximize economic return or minimize irrigation cost. This is particularly important for periods of peak demand. This paper describes a procedure to derive the optimal irrigation policy (depth and timing) which will minimize the total cost per unit time during each stage in the growing season of a single crop. The analysis is based on an inventory control model. First, the water depletion by the plant is derived. Then, the economic loss due to the decrease in yield caused by delaying irrigation and the cost of water application are considered. All the variables involved are considered as deterministic. A numerical example is presented to illustrate the use of the proposed method. Finally a sensitivity analysis is used to study the effect of uncertainties in the estimated quantities. 相似文献
13.
K. H. Solomon 《Irrigation Science》1984,5(3):161-172
Summary A number of irrigation performance parameters have been used to quantify irrigation uniformity and efficiency. These parameters are usually regarded as performance indices only, without a physically significant interpretation. Common irrigation uniformity and efficiency measures can be related to expected yields from non-uniform irrigation of certain hypothetical crops. Calculation of these measures is equivalent to, or closely related to, calculation of expected yields with non-uniform irrigation for the water-yield functions of Fig. 1. This relationship between performance measures and expected yield lends physical significance to irrigation uniformity measures, and suggests useful generalizations of traditional uniformity and efficiency measures that are directly related to crop yield.Contribution from the U.S. Salinity Laboratory, USDA-ARS, Riverside, CA 92501 相似文献
14.
Water scarcity in the Bojili irrigation District, which is located in the Shandong province in China, affects the management of the irrigation system and has led to the development of water storage functions inside the system. In particular, the irrigation and drainage scheme is used for short-term water storage whereas groundwater is used for long-term storage which is replenished during the monsoon season and drawn from when crop water requirements are not satisfied by surface irrigation.In this paper the storage functions are quantified. The role of groundwater, in relation to rainfall and irrigation depths, is analysed in detail. This analysis, which was carried out at the district and at sub-system scales, is based on data collected from fifty five observation wells between 1991 and 1996 at a 10-day time intervals. The sub-systems, called “divisions”, represent the areas for which irrigation-related information is available.Rainfall, groundwater levels and irrigation data are consistent. They demonstrate the inequity of water allocation between upstream and downstream water users. Accordingly strategies for water management differ between these users. These strategies only partially compensate the effects of scarcity demonstrated by decreasing cropping intensities from upstream to downstream parts of the District. 相似文献
15.
基于实时气象信息的灌溉决策支持系统,是利用实时的气象信息结合灌溉预报模型,实现灌溉管理的自动化、智能化。详细介绍了基于实时气象信息的灌溉决策支持系统主要的数学模型、系统结构及功能。与现有的灌溉管理系统相比本系统在改进了灌溉计划的制订流程、增加了实时气象预报的灌溉计划修正功能,并提供智能的人工干预功能;此外,结合数据分析技术和灌溉管理的实际特点,利用回归分析方法解决由于极端天气或数据采集过程中引起的数据缺失及错误问题,提供灌溉决策的准确性。实际应用表明,系统具有较高的实用性和准确性,为灌区灌溉管理提供了科学手段及依据。 相似文献
16.
为研究低压喷灌下喷灌机行、止速率比的合理取值,以自行研制的轻小型移动式喷灌机组为研究对象,通过室内组合喷头试验,探究行、止速率比与喷灌均匀性和喷灌强度的关系。通过spss软件进行方差分析,并采用多重比较分析法,进行差异显著性分析。结果表明:在工作压力为0.07 MPa情况下,行、止速率比对喷灌均匀性系数没有显著性影响,对喷灌强度具有显著性影响。当行、止速率比为45%时,喷灌均匀性系数在85%以上,同时喷灌强度为20.5mm/h,增大行、止速率比可小幅度的增大喷灌强度,60%的行、止速率比下喷灌强度为21.1mm/h,在90%时略有下降,达到19.97mm/h。喷灌强度基本趋于一致,可满足喷灌要求。 相似文献
17.
E. Playán J. Cavero I. Mantero R. Salvador S. Lecina J.M. Faci J. Andrés V. Salvador G. Cardeña S. Ramón J.L. Lacueva M. Tejero J. Ferri A. Martínez-Cob 《Agricultural Water Management》2007
In the last decade irrigation districts in the Ebro Valley of Spain have started to use database applications to enhance their management operations. Such applications often put more emphasis on administrative issues than on water management issues. A new irrigation district management software called “Ador” is presented in this paper. This database application has been designed to overcome limitations identified in an analysis of the software used in the study area. Ador can be used in irrigation districts independently of the type of irrigation system (surface, sprinkler or trickle) and the type of irrigation distribution network (open channel or pressurised). It can even be used in irrigation districts combining different types of irrigation systems and different types of irrigation distribution networks. The software can be used with minimum district information. The goals are to manage detailed information about district water management and to promote better on-farm irrigation practices. Ador is currently used to enhance management of 62 irrigation districts accounting for some 173,000 hectares in the Ebro Valley. 相似文献
18.
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
19.
Deficit irrigation has been suggested as a way to increase system benefits, at the cost of individual benefits, by decreasing the crop water allocation and increasing the total irrigated land. Deterministic methods are common for determining optimal irrigation schedules with deficit irrigation because considering the inherent uncertainty in crop water demands while including the lower and upper bounds on soil moisture availability is a hard problem. To deal with this, a constraint state formulation for stochastic control of the weekly deficit irrigation strategy is proposed. This stochastic formulation is based on the first and second moment analysis of the stochastic soil moisture state variable, considering soil moisture as bounded between a maximum value and a minimum value. As a result, an optimal deficit irrigation scheduling is determined using this explicit stochastic model that does not require discretization of system variables. According to the results, if irrigation strategy is based on deterministic predictions, achievement of high, long-term expected relative net benefits by decreased crop water allocation and increased irrigated land may have a higher failure probability. 相似文献
20.
基于随机降雨的水稻优化灌溉制度 总被引：3，自引：3，他引：0
为了确定合理的水稻灌溉制度,在水稻灌溉试验资料的基础上,建立了以旬灌溉水量为决策变量的水稻灌溉制度优化模型,采用了蒙特卡罗方法和漳河灌区30 a实际降雨资料模拟出500 a的旬降雨,运用遗传算法解决以模拟降雨作为输入的优化模型,求得了每个模拟年份各旬在5种设定的灌溉定额条件下的灌溉水量,并通过对结果的统计分析,得到了不同灌溉定额条件下作物生长情况和各旬灌水量的概率分布。结果表明,漳河灌区30 a长序列旬降水服从伽玛分布。灌溉定额为120 mm时,中稻不发生枯萎;灌溉定额为180 mm时,基本保证中稻生长良好。以30 mm为灌水定额步长,灌溉定额为180 mm时,6月上旬和8月上旬各灌30 mm,6月中旬和7月下旬各灌60 mm。6月中旬、7月下旬和8月上旬缺水对产量的影响较大,其需水量应优先被满足。 相似文献