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1.
Performance assessment of irrigation water management in old lands of the Nile delta of Egypt 总被引：1，自引：0，他引：1
Doaa E. El-Agha David J. Molden Ashraf M. Ghanem 《Irrigation and Drainage Systems》2011,25(4):215-236
This paper provides the methodology and results of a cross-scale diagnostic performance assessment program of the irrigation water management in the old lands of the Nile Delta of Egypt. The analysis was done at three levels; main canal level, branch canals level and on-farm level of the Meet Yazid command (82,740 ha) for the year 2008?C2009 to highlight areas for improvement. At the main canal level the annual average percentage of irrigation water returning to drains and groundwater was 53% of the total water supplied. Since Meet Yazid lies at tail end of the delta, and there is groundwater salinity, opportunities for reuse are increasingly limited moving north to Lake Burullus. This would indicate opportunities for real water savings. The results of monthly relative water supply of the main canal indicated mismatch between demand and supply especially during the winter months, and when supply is low farmers do reuse drainage or groundwater. Also, the assessment of the three branch canals showed non-uniformity of water distribution and mismatch between demand and supply even when comparing improved and non-improved canals. At the on-farm level in paddy fields, the amount of irrigation flows to drains and saline sinks varied from 0.46 to 0.71 of inflow. In spite of these values of non-uniformity and low depleted fraction, the relative evapotranspiration (ratio of actual to potential) evaporation was uniformly high, indicating most crops of most farmers were not water stressed, which is also confirmed by the high yield values. The average values of productivity per unit water depleted by ETact were 1.04 and 1.05 kg/m3 for rice and wheat fields, respectively, with yields of rice and wheat at 8 and 6 t per ha respectively. On farm and tertiary improvements alone will not yield real water savings, as excess water in the main canal and drains will continue to flow out of the system. Rather the focus should first be on supplies to the main canal, accompanied by more precise on farm and water delivery practices at branch and tertiary levels, and ensuring that environmental flows are met. There is an added advantage of focusing on this tail end region of Egypt that this response would lessen vulnerability to reuse of polluted and saline water. 相似文献
2.
Agricultural water is delivered by open irrigation canals in system of reservoirs with a widespread distribution in South Korea. Traditional irrigation management problems include water distribution systems with less capacity than the peak demand, irregular delivery rates, and low irrigation efficiency and uniformity. It is necessary to strategically compare the estimated irrigation demands with the actual water supplies for decision making in order to maintain the water supply according to the demand. Accurate measurement and monitoring of water distribution systems is essential in order to solve the problems of water efficiency and availability. Auto water level gauges installed at the head and tail sections of each irrigation canal in the Dongjin River were used to measure the discharge during irrigation periods. In this study, we introduced an approach to assess the water delivery performance indicators of the open irrigation canals, which is essential for identifying the key issues for water management improvement. The irrigation efficiencies according to the water delivery performance indicators were measured with an automatic water gauge in the irrigation canals and were calculated from the spatial and temporal distribution of the water supply for the lack of planning in water delivery. The calculated performance indicators are useful to understand the irrigator behavior and general irrigation trends. Analysis of the results yielded insights into possible improvement methods in order to develop water management policies that enable irrigation planners to improve the temporal uniformity and equity in the water distribution. 相似文献
3.
Large-scale canal irrigation projects are commonly seen as profligate users of water. Their low water productivity has been attributed by many authors to deficiencies in management or to actions by farmers to circumvent management control over water distribution. Inadequate design has sometimes been cited as a contributing factor, but the relationship between design and manageability has received too little attention. In most conventional large-scale irrigation systems imperfect matching between water supply and demand is an inescapable fact of life that leads to operational spillages and low efficiency. Provision of auxiliary storage reservoirs at strategic points within the canal system can buffer this mismatch and improve service delivery and also aid recovery of return flows. Such reservoirs may bring additional benefits in that they provide opportunities for multiple-use management and increased productivity of irrigation water. This paper presents a case study of Mahaweli System H in Sri Lanka, which incorporates a large number of secondary reservoirs within its 25000 ha command area. The paper examines current operational performance and considers scope for and constraints to multiple-use management. 相似文献
4.
《Agricultural Water Management》2001,47(1):37-53
Although rainfall in high rainfall regions is sufficient to meet the water demand of crops, its spatial and temporal distribution makes rainfed farming a risky proposition. Water harvesting can reduce the risk substantially by facilitating early planting by taking maximum advantage of the rainfall, thereby insuring the crop against rainfall aberrations. The proper design of a water harvesting system in a high rainfall region should take into account the spatial and temporal behavior of rainfall, water requirement of the crops, in addition to catchment characteristics. A simulation model has been developed to design a system for determining catchment/command area ratio, size of tank, desirable command area of a single tank and the feasibility/economics of lining of tank. The methodology facilitating the design of the system considered the catchment area characteristics, command area, and efficiency of conveyance system. It was found that for a rice-based cropping system in eastern India, a catchment/command ratio of 3.0 and tank size of 1750 m3/ha command area is required, which facilitates desirable moisture regime for rice and two irrigations to succeeding crop. The command area should not be extended beyond a limit to have a conveyance efficiency of 80% or more. Using traditional methodology, i.e. by total irrigation requirement method, the tank capacity requirement will be 4500–6000 m3/ha command area. 相似文献
5.
《Agricultural Water Management》1996,31(3):269-283
Rapid industrial development in the rice-growing regions has increased competition for the scarce water resources. Water reuse (surface and subsurface agriculture drainage water, storm runoff, sewerage effluent and industrial wastewater recycling) is in widespread use as a method of supplementing the paddy water supply, therefore, there is a need to clarify its effects on the paddy system water balance and riceland ecosystem. Field data and simulation results from a complex runoff model (created on a daily basis), were used to estimate the water balance and assess the effects on the irrigation system of a water shortage area in Niigata Prefecture, Japan. For three years (1991–1993), the average water reuse component was within the range 14∼ 15% of the total irrigation water supply. Apart from meeting the water needs at peak demand periods, water reuse is a quick-response water supply solution during dry spells, increasing both the water reliability and crop security. To understand the impact of water reuse on the riceland ecosystem, its effect on total phosphorus (T-P), total nitrogen (T-N), suspended solids (SS), and chemical oxygen demand (COD) was assessed. Blending of the drainage water was done to reduce the irrigation water concentrations, to approximate the traditional dual canal system and to increase farmer satisfaction with the water reuse system. Apart from the fact that the amount of return flow drained out of the irrigation system was reduced when drainage water was reused for irrigation, the effluent load reductions for SS and T-P owing to water reuse were consistently high. Hence, water reuse not only helps meet irrigation water needs, but also aids purification of the agricultural drainage water and preservation of the riceland ecosystem. 相似文献
6.
The WaDI (water delivery for irrigation) model deals with the relations between the collective water supply and the demand within irrigated schemes. It is based on a separate modelling of the water supply and demand, including (i) a simplified representation of the hydraulic structure, characteristics and organizational parameters of the scheme, (ii) an assessment of the water demand of farms based on their total irrigated area, cropping pattern and irrigation practices, (iii) a farm typology, (iv) a confrontation between water demand and supply at each node of the scheme from pumping plants to tertiary canals, and (v) calculation of response factors between supply and demand during the peak demand period. “What-if” scenarios are simulated in order to enhance the stakeholders’ capacity to plan strategic decisions such as water delivery allocation rules or infrastructure investments. WaDI was implemented on two Brazilian schemes. It allowed broadening the stakeholders’ limited representation of collective water supply and demand into a more comprehensive understanding of these relations. The approach however showed some limits, along with the difficulty of assessing the real impact on the stakeholders’ capacity for strategic planning. 相似文献
7.
基于物联网和云架构的渠灌闸门智能控制系统 总被引：1，自引：0，他引：1
为了实现农田明渠灌溉的精准化控制,设计了一种基于物联网和云架构的渠灌闸门远程智能控制系统,系统由一体化旋转式闸门、本地控制软件、远程终端访问系统和云端中间件组成。闸门采用旋转式阀芯结构设计,降低闸门启闭时的驱动能耗;基于ARM开发了嵌入式控制系统,实现水闸运行的本地控制和状态数据采集;集成了无线通讯模块和光伏电源系统,解决传统水闸野外安装布线繁琐和供电困难问题;通过在阿里云服务器建立数据中心,部署中间件,实现水闸远程数据传送与控制指令传达;建立了基于水位、流量双反馈的闸门开度云控模型,实现水闸群智能运行;根据旋转式闸门启闭阶段角速度变化规律,提出了水闸运行异常报警方法;开发了B/S版和APP版的远程终端访问系统,实现了灌区数据大屏、闸群远程控制和智能调度,适用于农田灌溉中小型渠道输水、配水的精准化控制。 相似文献
8.
N.K. Tyagi A. Agrawal R. Sakthivadivel S.K. Ambast D.K. Sharma 《Irrigation and Drainage Systems》2004,18(1):73-88
Investigations were made to study the effect of unequal distribution of canal water in land and water productivity of the rice—wheat cropping system in terms of head—tail relationship in Bhakra Canal command, Haryana. Information on water supply, agronomic practices, crop yield, etc.,were collected from 216 farmers comprising 36 farmers each from the head, middle, and tail watercourses of two minors during year 2000–01. The unequal supply of canal water and presence of marginal quality groundwater creates large variations in the cropping pattern, irrigation application, and land and water productivity of the irrigation system. The groundwater of tail reaches, being saline in nature, was about 25% less productive as compared to head reaches. The unavailability of canal water in the tail reaches creates more dependency on groundwater. Due to its poor quality the crop production in the tail reaches was less by 10 to 20% in case of wheat, and 20 to 40% in case of rice, as compared to head reaches. Groundwater transfer from head to tail reaches and cultivation of low water requiring salt tolerant crops/varieties would be helpful in reducing the productivity gap and increasing the profitability of the farms in the region. 相似文献
9.
Rice–Wheat rotation system utilizes surface, ground and rain water resources conjunctively. Recent studies have shown increasing
contribution of groundwater for crop irrigation. As the system utilizes water pumped from the underlying aquifer and partly
seeps back, a cycle of recharge and discharge continues. Sustainability of groundwater system for the on-going drought in
the country depends mainly on the recharge of the aquifer. The reported study was, therefore, carried out to measure and assess
the recharge contribution of a distributary of canal in Punjab, Pakistan. Assessment of recharge through distributary was
carried out using a groundwater flow “MODFLOW” model, which utilized the observed watertable, climatic, crop and soil for
a period of about 1 year in addition to hydraulic conductivity, evapotranspiration and aquifer characteristics data. The requisite
primary data for “MODFLOW” were collected from field and secondary data from public sector organizations dealing with water.
Model calibration involved changing input parameters within reasonable limits until acceptable matches were obtained between
the observed and simulated water levels for all observed hydrographs. The external inputs such as, recharge through irrigation,
precipitation, stresses due to evaporation, lateral flow and stream were simulated to calculate the monthly water budget of
aquifer. As concluded, recharge contribution was 16.5% of the inflow rate of the distributary. Using predicted results of
the model a relationship between recharge (R) and discharge (Q) was also developed. Although, the presented results of recharge
contribution were limited to one distributary of canal irrigation system, yet the developed methodology can be extended to
the other canal systems of the Indus Basin. 相似文献
10.
The Upper Swat Canal (USC) System became operational in 1917–1918 in North West Frontier Province (NWFP) of Pakistan. The
rehabilitation and modernization of the USC was undertaken with a view to overcoming the shortage of water supplies for irrigation.
The water allowance was enhanced from 0.39 to 0.77 Ls−1 ha−1 in the study area. Recently, the operation and management of a secondary canal or ‘distributary’ was transferred to the Farmers
Organization (FO). This distributary named ‘Chowki’ offtakes from the Maira Branch of the USC. The cultivable command area
(CCA) of this distributary is 4,306 ha and it serves 1,485 beneficiaries. A management committee on Chowki Distributary was
formed in 2003. This distributary consists of one main and two minor channels having twenty-eight direct outlets. The Simulation
of Irrigation Canal (SIC) hydrodynamic model was used to evaluate the flexibility of Chowki Distributary. The model was calibrated
at 100, 80 and 70% of the design discharge (Q
d) and it was validated at 90, 85 and 60% of the design discharge. The observed and simulated water levels were in close agreement
with each other for the calibration and validation periods. The statistical analysis and paired t-test indicate that the model results are not statistically different from the measured values at 1% significance level. The
simulated results of the SIC model were applied to studying flexibility of the outlet structures along the Chowki Distributary.
The flexibility analysis demonstrates that poor performance is inbuilt into the system due to inadequate control over the
accuracy of the crest setting during the construction of the outlets. 相似文献
11.
A method is presented to analyse the impact of the selection of irrigation gates on operational performance of the Sungai Muda Irrigation Scheme in Malayisa. The method examines the discharge capacity of the water control gates at all levels in order to compare the specific water supply (the ratio of supply to command area) with the specific water demand which is the required hydromodule. The term hydromodule is the reciprocal of water duty and thus has units of litres/second/hectare. The greater the deviation between the two, the greater the potential loss of control during the operation of the scheme. The method is relatively simple but is more complex in this particular example as two hydromodules are used for the irrigation of basin rice; one for the presaturation period and one for the normal supply period. The most common cause of loss of water control is found to be provision of oversized turnout gates at the head of secondary and tertiary canals. Such design approximations enable more water to be used in those command areas thus leading to waste and to shortage of water in other areas. It is suggested that during design and rehabilitation of irrigation schemes, the operational implications of design approximations should be examined more carefully. 相似文献
12.
This work addresses management of water for irrigation in arid regions where significant delays between the time of order and the time of delivery present major difficulties. Motivated by improvements to water management that will be facilitated by an ability to predict water demand, it employs a data-driven approach to developing canal flow prediction models using the relevance vector machine (RVM), a probabilistic kernel-based learning machine. A search is performed across model attributes including input set, kernel scale parameter and model update scheme for models providing superior prediction capability using the RVM. Models are developed for two canals in the Sevier River Basin of southern Utah for prediction horizons of up to 5 days. 相似文献
13.
The equitable distribution of canal water is imperative to ensure social justice as well as crop productivity. In north-west
India and Pakistan, water from the tertiary canal (watercourse) is distributed to the farmers through a rotational system
of irrigation. In this system the duration of supply to each farmer is in proportion to his holding in the outlet (watercourse)
command, without considering the seepage loss. The rate of seepage loss increases with increase in length of watercourse from
head to tail. Thus, the farmers in the lower reaches get much less water per unit area than the farmers in the upper reaches.
The farmers must be compensated for the seepage loss. Therefore, a model was developed to ensure equitable distribution of
water to the farmers located on a watercourse in proportion to their land holdings giving due compensation for the seepage
loss. The model is based on the assumption that soil throughout the length of flow is homogeneous and loss through evaporation
is negligible. The model developed ensures an equitable distribution of water to the farmers according to their land holdings.
A comparison of existing and revised time allocation reveals that the farmers located in the upper reaches were getting more
time (up to 12.2 min per unit area), while the farmers located in the lower reaches have been getting less time (up to 28.1 min
per unit area). The existing allocation of time of 0.75 h per unit area to all the farmers according to the old rules was
revised to 0.546–1.219 h per unit area from head to tail. The conclusions drawn suggest that the strategy developed here should
be adopted elsewhere in the existing system of irrigation for equitable distribution of canal water.
Received: 21 December 1999 相似文献
14.
以拉萨河下游河谷地区为研究对象,依据1989-2010年拉萨、墨竹工卡气象站气象资料和Landsat卫星遥感影像提取的主要作物(青稞、冬小麦及油菜)种植面积,计算不同典型年份研究区总灌溉需水量;结合拉萨水文站1989-2010年径流序列资料,分析区域灌溉用水的供需平衡.结果表明:拉萨河谷地区的种植模式以粮食作物为主,河谷区种植面积在1990-2010年间增长约8%,作物种植结构没有发生显著性的变化.农作物种植面积的增加引致灌溉需水量大幅度增加,2010年的灌溉需水量达到16亿m3,比1990年增长约35%,青稞为灌溉需求最大的作物.河流径流量及灌溉用水需求的季节性变化存在差异,每年4-6月灌溉供需关系较为紧张,灌溉量占径流量近10%~20%,每年12月至次年4月正值河流枯水季,尽管该期间灌溉需水量较低,但对水资源造成的压力也是不容忽视的.拉萨河谷地区水资源供需关系较为紧张. 相似文献
15.
Real-time forecasting of short-term irrigation canal demands using a robust multivariate Bayesian learning model 总被引：1，自引：0，他引：1
In the lower Sevier River basin in Utah, the travel times between reservoir releases and arrival at irrigation canal diversions limit the reservoir operation in enabling delivery changes, which may not be compatible with the on demand schedule in the basin. This research presents a robust machine learning approach to forecast the short-term diversion demands for three irrigation canals. These real-time predictions can assist the operator to react promptly to short-term changes in demand and to properly release water from the reservoir. The models are developed in the form of a multivariate relevance vector machine (MVRVM) that is based on a Bayesian learning machine approach for regression. Predictive confidence intervals can also be obtained from the model with this Bayesian approach. Test results show that the MVRVM learns the input–output patterns with good accuracy. A bootstrap analysis is used to evaluate robustness of model parameter estimation. The MVRVM is compared in terms of performance and robustness with an Artificial Neural Network. 相似文献
16.
针对西北干旱区农业水资源短缺的问题,以新疆洛浦县为例,从作物种植结构调整和灌溉面积变化、灌溉水利用系数提高及灌溉方式改变等方面进行节水分析,并对预测水平年农业供需水平衡进行了预测计算,预测结果表明：现有的灌排工程不能满足农业可持续发展要求;提高灌溉水利用系数势在必行;采用滴灌技术极大地减少了农业用水量,是解决农业供需水矛盾的有效措施。最后,根据预测结果,提出了解决农业水资源短缺、可持续发展的对策,为其他区域水资源的合理开发利用提供有益的参考。 相似文献
17.
18.
Continuous upstream water development in the South Indian Krishna Basin has resulted in declining water availability downstream. Upstream water use is not adjusted to reflect rainfall fluctuations, and downstream farmers of the Nagarjuna Sagar irrigation project in the state of Andhra Pradesh are increasingly vulnerable to water supply shocks. Understanding the adaptive capacity of irrigated command areas to fluctuating water conditions is critical. This paper documents the wide range of adjustments adopted by managers and farmers in Nagarjuna Sagar during a period of fluctuating water availability (2000-2007). Primary and secondary data indicate managerial adjustments such as rotational and timely water supplies to meet critical water demands of standing crops. Farmers responded to changing conditions through: (a) crop diversification, (b) shifting calendars, (c) conjunctive use, (d) suspending cultivation, (e) sale of livestock, (f) out-migration, and (g) tampering with the irrigation system. Adaptive strategies are more diverse in the tail-end than in the head-end of the canal network and local adjustments are often uncoordinated and may degrade the resource base. A better understanding of the practices induced by changes in water availability is needed to refine current water allocation and management in large surface irrigation projects. Crop diversification, deficit irrigation in low-flow years, and conjunctive use are some of the practices to be promoted in a conducive agricultural environment. 相似文献
19.
Results are presented of field research on water distribution in the command area, covering 18,200 ha, of a secondary irrigation canal in the Tungabhadra Left Bank Scheme, Karnataka State, India.The official objective of the Scheme and the resulting implications for the water distribution are discussed first. An explanation of the planning and operation of the water distribution follows.The results are based on analyses of the water flows taken from the D36 secondary canal and distributed along the canal to the pipe outlets (inlet structures to the tertiary units), and of the canal section rotation practised along the canal. The analyses concentrate on three dimensions of the water supply:The design flows, according to the official Scheme objectives and criteria;The targets, as set by the system operators before every season;The actual distribution procedures and flows, as observed during the operation.The analyses, supported by flow measurement data, illustrate that the water distribution is not based on consistent and clear criteria and procedures, but that it is the outcome of varying compromises, decided upon pragmatically by the field staff, to bridge the gap between the farmers' demands and the upstream constraints to water availability. This paper explains the widespread phenomenon of head reaches taking too much water, leaving little or nothing for the tail end of the canal. 相似文献
20.
The non-uniformity of soils, weather, fields, cropping pattern and canal systems in most surface irrigation schemes makes irrigation water management complex, but optimum performance is important particularly in irrigation schemes with limited water supply. This paper focuses on the performance of irrigation water management during the area and water allocation with a case study of an irrigation scheme in the semi-arid region of India. Often the irrigation managers or authorities of these heterogeneous irrigation schemes also need to deal with different allocation rules. The allocation plans and the corresponding water delivery schedules during the allocation process were estimated with the help of a simulation–optimisation model for different allocation rules based on cropping distributions (free and fixed), water distributions (free and fixed-area proportionate), irrigation depth (full, fixed depth and variable depth irrigation) and irrigation interval (from 14 to 35 days). The performance measures of productivity (in terms of net benefits and area irrigated), equity (in water distribution), adequacy and excess were assessed for these different allocation plans and schedules. These were further compared with the performance measures of the existing rule (fixed depth irrigation at a fixed interval). The analysis revealed that these performance measures are in some cases complimentary and in other cases conflicting with each other. Therefore, it would be appropriate for the irrigation managers to understand fully the nature of the variation in performance measures for different allocation rules prior to deciding the allocation plans for the irrigation scheme. 相似文献