Role of Groundwater in Irrigation Water Management in the Downstream Part of the Yellow River

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.     

Simulation of automatic control of an irrigation canal

Improved water management and efficient investment in the modernization of irrigation schemes are essential measures in many countries to satisfy the increasing demand for water. Automatic control of the main canals is one method for increasing the efficiency and flexibility of irrigation systems. In 2005, one canal in the irrigation scheme ‘Sector B-XII del Bajo Guadalquivir’ was monitored. This canal is representative of irrigation schemes in Southern Spain; it is divided into four pools and supplies an area of 5154 ha. Ultrasonic sensors and pressure transducers were used to record the gate opening and water levels at the upstream and downstream ends of each canal pool. Using the recorded data and the SIC (Simulation of Irrigation Canals) hydraulic model, two canal control options (local upstream control and distant downstream control) were evaluated using a PI (Proportional-Integral) control algorithm. First, the SIC model was calibrated and validated under steady-state conditions. Then the proportional and integral gains of the PI algorithm were calibrated. The controllers were tested using theoretical demand changes (constant outflow followed by a sudden demand increase or decrease) and real demand changes generated on the basis of a spatially distributed crop water balance that included a number of sources of variability (random and not random) in the determination of field irrigation timing and depth. The results obtained show that only the distant downstream controller was able to adjust quickly and automatically the canal dynamics to the varying water demands; it achieved this efficiently and with few spills at the canal tail, even when there were sudden and significant flow variations.     

Irrigation with saline water: benefits and environmental impact

The shortage of water resources of good quality is becoming an important issue in the arid and semi-arid zones. For this reason the availability of water resources of marginal quality such as drainage water, saline groundwater and treated wastewater has become an important consideration. Nevertheless, the use of these waters in irrigated lands requires the control of soil salinity by means of leaching and drainage of excess water and salt. However, the leaching of salts, soil microelements and agro-chemicals can lower the quality of the drainage water in the irrigation scheme. The irrigation return flows with water or poor quality are a source of pollution of the surface water bodies situated downstream of the drainage outlet. Deep percolation could also contaminate the groundwater. Therefore, irrigation with saline water requires a comprehensive analysis even beyond the area where water is applied. The problem should be treated beyond the scope of the irrigation scheme, taking into consideration the groundwater and downstream surface water resources of the river basin. Consequently, the sustainable use of saline water in irrigated agriculture requires the control of soil salinity at the field level, a decrease in the amount of drainage water, and the disposal of the irrigation return flows in such a way that minimizes the side effects on the quality of downstream water resources. This paper describes the guidelines for a preliminary evaluation of the suitability of water for irrigation and the key factors for salinity control in lands irrigated with saline water. Options to improve the quality of the drainage water, strategies for the reuse of this water and alternatives for disposal of the outflow are also analysed. The final goal is to obtain sustainable agriculture and maintain the quality of the water resources in the river basin.     

Reuse of drainage water in irrigation with the aid of 0-1 linear programming

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.     

Automatic dam management and river regulation for irrigation purposes

In FRANCE, for about twenty years now, water control has been achieved in canals specially designed for optimum efficiency in water conveyance and distribution. The regulation techniques consist in particular in using downstream or upstream float gates and baffle distributors — often used in Morocco for example. Their use implies specially designed canals with adapted civil engineering works and dykes. The application of these regulation techniques on old canals with continuous flow very often implies heavy investment and is impossible on natural rivers. On the other hand, the development of micro-computers and data transmission networks, and the definition of mathematical methods dealing with control systems, have pointed the way to another approach to the problem set by improving the efficiency of the feeder canal control. Using these new techniques, the Compagnie d'Aménagement des Coteaux de Gascogne (CACG), in collaboration with a staff of researchers, has studied a new approach to water management, and since 1984 has produced a complete set of automatic control equipment allowing the irrigation of 4000 ha, with a system efficiency close to 0.9. This approach has been set up in particularly difficult conditions, the river being used to supply several irrigated perimeters. It could as easily be installed on a canal, where it is not economical to invest in the large hydraulic structures necessary for traditional control.; The economic stakes are important because it is a matter of improving the performance of existing structures with little specific investment (sensors, micro-computers, software) and with extensive improvement in the systems management.     

A model to estimate timing of aquatic weed control in drainage canals

In many parts of the Netherlands a dense network of watercourses is necessary to drain the land. A related aspect is thechanging transport capacity of the water courses due to thegrowth of aquatic plants in the growing season. In turn thisphenomenon requires aquatic weeds to be controlled by waterboards in order to maintain the water course's required capacity.The procedure outlined in this paper can be used to determinethe frequency of weed control based on hydrological andhydraulic conditions. The drainage from groundwater gives anexpected variation in discharge over the growing season. Thepermissible flow rate is governed by both the growth of weedsand the permissible water levels in the water course. Weedcontrol is necessary during the growing season when theexpected discharge is more than the permissible flow rate. Thisprocedure has been incorporated in the model MWW(Maintenance of Water courses by Water boards). An examplehow to use MWW is given.     

盐碱地排水沟水体盐分变化规律

为了研究陕西卤泊滩盐碱地排水沟在排水出路受阻,上游灌区退水导致排水沟周期性较高水位运行条件下的水体盐分变化情况,选择研究区3条排水沟,进行野外水盐监测试验,测定了排水沟水体盐分随时间的变化规律.研究结果表明:在当前条件下影响研究区排水沟水量的主要因素为干旱蒸发和上游灌区退水.干旱期排水沟水量较少,上游灌区低含盐量的退水进入研究区排水沟内,致使水量显著增大,在研究区下游排水沟内水深达1.15 m;排水沟水体电导率值在干旱季节较高,盐分从上游至下游呈现出一定的富集现象;上游监测点位水体电导率基本维持在2~14 ms/cm,下游水体电导率值高达25.2 ms/cm;研究区上游灌区退水在排水沟内大量蓄积,使得排水沟水体电导率值降低至1.9 ms/cm,稀释率高达10倍,表明退水可以稀释排水沟中的盐分水平,维持排水沟水体盐分平衡,达到排盐效果.     

Blue node concept: a regional water management strategy

Water scarcity is, in general, not a problem in the Netherlands. Scarcity is caused by pollution and especially non-point pollution. For the water manager the central task is the supply of water with good quality at the right time at the right place. This task depends on the demand of the different kinds of land uses, the stock of water in the area during the year, and the possibilities to separate parts of the water system with bad water quality from parts with good water quality. To do so the blue node strategy has been developed and is illustrated in this article.     

Controlled water table management as a strategy for reducing salt loads from subsurface drainage under perennial agriculture in semi-arid Australia

Recent community based actions to ensure the sustainability of irrigation and protection of associated ecosystems in the Murrumbidgee Irrigation Area (MIA) of Australia has seen the implementation of a regional Land and Water Management Plan. This aims to improve land and water management within the irrigation area and minimise downstream impacts associated with irrigation. One of the plan objectives is to decrease current salt loads generated from subsurface drainage in perennial horticulture within the area from 20 000 tonnes/year to 17 000 tonnes/year. In order to meet such objectives Controlled Water table Management (CWM) is being investigated as a possible ‘Best Management Practice’, to reduce drainage volumes and salt loads.During 2000–2002 a trial was conducted on a 15 ha subsurface drained vineyard. This compared a traditional unmanaged subsurface drainage system with a controlled drainage system utilizing weirs to maintain water tables and changes in irrigation scheduling to maximize the potential crop use of a shallow water table. Drainage volumes, salt loads and water table elevations throughout the field were monitored to investigate the effects of controlled drainage on drain flows and salt loads.Results from the experiment showed that controlled drainage significantly reduced drainage volumes and salt loads compared to unmanaged systems. However, there were marked increases in soil salinity which will need to be carefully monitored and managed.     

淮河三河尖水位站特征水位分析研究

特征水位是防汛预警决策的重要依据.近年来,淮河三河尖水位站经常出现大范围、长历时的水位超警,现有的特征水位已逐渐不能适应当前防汛工作需要.采用上下游水面线分析、水力学法、水位过程线对比分析和最高水位年频次分析等方法分别得出相应的特征水位,综合考虑堤防超高、特征水位确定原则以及抗洪抢险联动性等因素,提出更为合理可行的特征...     

水资源不均等分配及其影响分析以簸箕李灌区为例

以簸箕李灌区为例,分析了该灌区水资源不均等分配及其所带来的对水资源利用方式和效率的影响。结果表明,在灌区内部从上游到下游,水资源可利用量很不均等,上游享用更多的水资源,地下水起到了调节水资源可用量年内波动的作用。上游地区地下水调节了春季水资源可用量的变异性,下游汛期储存的地下水在来年春季被重新利用,年平均利用量达到降雨灌溉总量的40.7%。下游农民应对水资源短缺的另2种途径是进行排水管理和减少种植面积,平均排水再利用量达到40 mm,因此下游地区具有更高的水资源利用效率。在水资源配置中应注意配置方案对水资源利用方式和效率的影响,同时要兼顾效率和公平。     

石羊河流域井灌区土壤水分深层渗漏研究

基于土壤水分亏缺、总有效水分和实际有效水分的概念,建立土壤水分水量平衡模型,通过计算作物根系层的深层渗漏量,来反映土壤水与地下水之间量的相互转化关系。研究结果表明,研究期间的总深层渗漏量为9 4.1 9 mm,占研究期间总灌水量和降雨量的2 0.1%,这部分水量通过根系层补给下层土壤,最终补给地下水。     

Delivery system performance case study: Wellton-Mohawk irrigation and drainage district,USA

An irrigation district in southwestern Arizona was studied to assess the performance of its water delivery system. Data were obtained through monitoring of lateral canals, examining water order reports and bills, and conducting a diagnostic analysis of the water delivery and on-farm irrigation systems through interviews. A number of differences between official andde facto district operating policies were found. These policies had changed over the years and provided far more flexibility and better service than provided by the original official policy. The canal system, which was designed to be operated under upstream control, was found to be operated under a complex mixture of manual upstream and downstream control that resembled dynamic regulation. Farmers made official (recorded) water orders only about half the time. Deliveries usually occurred within one day of the ordered date, as per district policy, with more late deliveries at the tail end of the system during peak water use periods. On average, the district delivered the rate and duration ordered, but average flow rates for individual deliveries were not accurately estimated due to fluctuating flows. The two biggest shortfalls observed were the lack of water measurement records at intermediate points in the system and lack of thorough water accounting. These shortfalls appeared to have had only a minor effect on overall district objectives.     

陕西沣河水环境特征及污染构成解析

通过资料收集和现场监测,对沣河2001-2011年水污染时空变化特征和成因进行了分析;在沣河秦渡镇水文站断面进行了洪水期与非洪水期水质水量同步监测,分析比较了洪水期和非洪水期水质特征;分别采用构建的水文分割法和通用的平均浓度法对沣河非点源污染负荷及其比重进行了计算。结果表明：（1）沣河2001～2006年污染较严重,2007～2011年水质逐年好转;2001～2006年从上游到下游沣河水质沿程逐渐恶化,2007～2011年沣河流域水质污染情况为上游<下游<中游;沣河2001～2006年NH3-N平均浓度基本处于Ⅲ类水质以内,2007～2011年基本处于II类水质以内;沣河2005~2006年COD平均浓度处于IV类水质以内,2007～2011年处于II类水质以内;洪水期水质好于非洪水期水质。（2）水文分割法和平均浓度法计算结果符合良好,该法可用于有限资料条件下非点源污染负荷的估算。沣河非点源污染影响在2007年后明显增大,2009年（P=45%）沣河秦渡镇水文站以上流域NH3-N和TN非点源污染负荷在总负荷中所占比例分别为47.40%和50.78%。NH3-N和TN年内非点源污染负荷所占比重从枯水期到丰水期呈明显递增趋势。     

黄土高原地区水土保持减水减沙效

水土流失是西北黄土高原地区生产和生活环境不断遭受破坏的重要原因，严重的水土流失不但危害着该区的生态环境，而且大量入黄泥沙进入下游，导致河床不断抬高，给下游防洪及农业生产造成危害。近年来，众多水土保持工作者进行了大量的探索、研究与实践，提出许多水土保持模式，探讨了评价水土保持模式减水减沙效益计算的水文法，SCS模型法以及水保法，并对三种方法就同一实例进行计算和对比分析，给出合理性建议。     

基于水动力学模型的渠道流量控制系统研究

针对渠道流量较大、水流条件复杂的流量测量问题，提出一种水动力学模型的渠道流量计算方法，并以此搭建基于水动力学模型的渠道流量控制系统。首先建立水动力学数学模型，采用两点水位量水法计算渠道流量，即在闸门上、下游选择两个断面，利用水位传感器实时测量断面水位数据，通过上位机求解水流控制方程得到两处断面的流量，取均值作为渠道的流量值，其次结合PLC搭建渠道流量控制系统，根据调度要求控制闸门的启闭，实现渠道流量的精准控制。在加大供水流量、水流条件复杂条件下，流量计算结果与多声道超声波流量计所测数据相比，平均偏差率小于5%。通过试验研究表明：控制系统流量控制误差为0.514%，系统响应时间小于200 ms，平均无故障运行时间大于10 000 h。控制系统的研究为后续渠道流量调度工程建设提供理论依据和案例支撑，具有较强的应用价值。     

农田排水对塔里木河水质盐化的影响研究

在塔里木河流域农田排水的发展可以划分为三个阶段,即“旱排水”、排水渠建立和逐步完善阶段。农田排水虽对灌区内部的盐渍化治理起到了很大的作用,但排水进入河流对河水的水质盐化影响很大。所以应寻找新的排水出路,多途径排水。同时发展节水灌溉,改变传统的排水洗盐方式,才是干旱区农业发展的方向。     

太湖流域平原河网地区引水河道水质控防消纳技术研究

针对太湖流域平原河网地区引水河道水质受联通支河、排水口影响及水安全要求高特性,提出防控重点及关键环节,构建自陆域至水域、从上游到下游外的全方位立体式污染物防控消纳技术体系,确保引水安全。     

基于水文水动力模型的浦阳江流域洪水情景模拟

浦阳江流域地形复杂,包括山丘、盆地和平原.中游诸暨盆地是人口主要聚集地,受上游山区洪水和下游钱塘江潮位顶托影响,洪涝灾害形势严峻.为解决上述问题,本文对流域上游山区采用新安江水文模型模拟降雨径流过程,对下游盆地区采用IFMS一、二维水动力模型模拟水流运动,并以水文模型的计算结果作为水动力模型的边界条件进行水文水动力模型...     

Water ‘banking’ in Fergana valley aquifers—A solution to water allocation in the Syrdarya river basin?

The Syrdarya river is an example of a transboundary basin with contradictory water use requirements between its upstream and downstream parts. Since the winter of 1992-93, the operational regime of the upstream Toktogul reservoir on the Naryn river - the main tributary of the Syrdarya - has shifted from irrigation to hydropower generation mode. This significantly increased winter flow and reduced summer flow downstream of the reservoir. Consequently, excessive winter flow is diverted to the saline depression called Arnasai, while water for summer irrigation is lacking. This study suggests to store the excessive winter flows temporarily in the upstream aquifers of the Fergana valley and to use it subsequently for irrigation in summer. It is estimated that groundwater development for irrigation could be practiced on one-third of the irrigated land of the valley, and conjunctive use of groundwater and canal water on another third; the rest will remain under canal irrigation. This strategy will lower the groundwater table and create aquifer capacity for temporal storage of excessive water—“water banking”. This use of the term is only one of many concepts to which “water banking” or “groundwater banking” is applied. In this paper, the term is applied for temporary storing of river flow in subsurface aquifers. Pilot modeling studies for the Sokh aquifer - one of the 18 aquifers of the Fergana valley - supported that this strategy is a feasible solution for the upstream-downstream issues in the Syrdarya river basin. Field studies of water banking are required to determine the scale of adoption of the proposed strategy for each aquifer of the Fergana valley.