Impacts of agricultural policy on irrigation water demand: a case study of Saudi Arabia

Saudi Arabia's groundwater resources have been heavily over-exploited to achieve food self-sufficiency. The country enacted a new agricultural policy that discourages the cultivation of wheat and encourages that of vegetables and fruits. This has produced significant reductions in irrigation water demand as well as food self-sufficiency. This paper reviews the performance of the Saudi agricultural sector and presents four scenarios forecasting the new policy's long-term impacts on the use of water for agriculture. The findings show that the new policy does not support sustainable utilization of groundwater resources. Additional policy modifications are needed to optimize the combination of import and domestic production of agricultural products based on a sustainable water utilization strategy.     

Water demand versus supply in Saudi Arabia: current and future challenges

Saudi Arabia is facing a chronic water-shortage problem. Demand far exceeds the sustainable yield of both conventional and non-conventional water resources. The resulting demand–supply gap is being bridged through groundwater depletion. In this paper, demand–supply gaps for the coming 20 years are projected under three scenarios: optimistic, moderate and pessimistic. Future sustainable water yields are calculated and allocated to projected water demand in the domestic, industrial and agricultural sectors. The study shows that Saudi Arabia will not be able to bridge the demand–supply gap in the near future. Intensive water demand management measures are needed in all sectors to minimize future demand–supply gaps, especially focused on the largest water consumer: the agricultural sector.     

Towards the Establishment of Water Management in Abu Dhabi Emirate

The Abu Dhabi Emirate is the largest of the seven emirates that compose the United Arab Emirates (UAE). Parallel to the growth of the country, the Abu Dhabi Emirate has witnessed remarkable development in many aspects of life over the past 35 years. This rapid development into a modern urban environment and the accompanying surge in population, caused by a major influx of foreign labor, have been imposing tremendous pressure on natural resources including water. The challenges of maintaining a sustainable freshwater supply in the Abu Dhabi Emirate are many. Conventional water resources are limited. Surface water is almost absent due to the scarcity of rainfall coupled with arid conditions. Groundwater is mostly brackish and nonrenewable. Over-pumping practices have resulted in a severe decline in groundwater levels and quality. The growing salinity in the ground water has impacted the increased salinity of agricultural land. In addition, water availability and demand are both subject to seasonal fluctuations, particularly during the hot and humid summer months. In the Abu Dhabi Emirate there is a high demand for freshwater used for irrigation of farmland, forests and landscaping; industrial and commercial uses; amenities and domestic use. A large portion of this demand is provided by desalinated water, which is expensive to produce. The need for rational water management is critical. Forecasting water demand is currently being used as the basis for the production expansion planning in order to meet the water demand for the emirate. With steady projected increases, the capacity to provide a continuous supply of freshwater is vital. Interruptions in the supply can be caused by emergencies and the minimum 1-year lead time needed for new desalination plant construction. Having an adequate storage system addresses some of the concerns related to establishing a freshwater supply. The Abu Dhabi Emirate needs long-term storage capacity equivalent to at least 1 year’s fresh water demand. One method of increasing this capacity is artificial recharge using excess produced desalinated water and treated wastewater. While there are currently pilot projects using this technique, more widespread use could be very beneficial. This paper describes the current water resources, water demands and techniques of storing water for future recovery in the emirate through artificial recharge techniques.     

灌区水资源实时优化调度

根据实时调度原理及农业水资源配置特点,建立了分层耦合的水资源实时优化调度模型,该模型包括供需水中长期预测、中长期优化配置、供需水实时预报、短期渠系配水和基于模糊识别的实时修正5个模块,应用该模型可实现对预报、决策、实施、修正的滚动向前调度。在中长期优化调度模块中提出了利用模糊聚类和马尔科夫时间序列的预测方法对有效降水量进行预测,并根据预测的年型计算作物需水量和地下水可开采量。实例计算表明,应用该模型实行的实时优化调度与各种供水已知情况下的理想最优调度方案偏差较小。     

基于单位象元尺度的黑龙港流域农用地下水资源供需分析

水资源匮乏和土地资源相对贫瘠是黑龙港流域最为严重的资源环境问题,基于对研究区遥感图像进行监督分类后得到的农业种植结构的分析,并运用作物缺水量和地下水资源供需短缺量、供需比的计算模型,开展了单位象元尺度的农业水资源供需平衡研究。结果表明,研究区冬小麦、水果和蔬菜分布较多的区域缺水最为严重,缺水量2 400m3/hm2以上的达到1.45万km2,占总面积的42.2%。据此,提出了区域水土资源优化配置方案,即在水资源短缺、土壤盐渍化或沙化地区,以种植耐干旱和耐盐咸的作物为主;在水资源丰沛、土壤有机质含量高和保蓄能力强的地区,以种植对水土资源要求高的作物为主。     

山东省沂源县水资源现状及持续发展对策

对山东省沂源县地下水资源进行定量评价 ,对地表水和地下水的水质现状进行定性分析 ,为解决沂源县可持续发展所面临的水资源紧缺问题 ,提出在不引起环境问题的前提下 ,加大地表水的利用量 ;用已轻度污染的地表水进行农灌 ,利用土壤的净化作用 ,去除污染水中的有害成分等方法 ,达到治理污染 ,满足用水需要的目的。     

基于水资源现状的黑龙港流域农业节水技术分析

通过对目前黑龙港流域水资源利用现状的分析,从浅层微咸水利用、生物节水、优化农业种植结构以及耕作技术等方面阐述了该区域农业节水技术的研究进展,提出了必须采取综合技术措施建设节水型现代化农业,才能从根本上解决黑龙港地区水资源供需平衡与可持续发展。     

农业节水首先要合理调控利用当地水资源

我国灌区妈水的利用率低，水浪费严重，这是农业节水主要潜力之所在。灌区应以开发利用浅层地下水为基础，引地表水作补充，采取井渠结合地表水地下水联合运用的灌溉方式，合理调控利用当地水资源。在靠井灌溉没有渠灌水源的地区，要拦蓄降雨径流及汛后河水回补地下源。在有条件开发地下水的河水灌区，要井渠并用，优化调度水资源。在灌溉管理上，要按农业用水量控制灌溉水量。建议按流域和灌区工发利用和管理水资源，在河水灌区积极     

汾河灌区存在的问题和发展对策

汾河灌区灌溉供水严重不足，每年平均只灌一次，每亩次净灌５７ ｍ３ ，严重制约着农业生产的发展。为此，加速发展河井双灌，合理引用区间（ 洪） 水，取消沿河高灌抽水，发展工业供水市场，开展节水灌溉等，可促进灌区农业的持续发展。     

Policies for water resource management in semiarid regions

Many of the freshwater problems of the 21st century will arise from increasing demands for water generated by rapid population growth, urbanization, industrialization and irrigation needed to satisfy the additional demand for food. The increased demand for water is being exacerbated by the excessive pumping of groundwater aquifers, some of which hold ancient or fossil’ water, and by the deteriorating quality of both surface and groundwater supplies. When it comes to the role and the fate of water resources in semiarid environments, despite the many differences socially, politically, culturally and economically among regions around the globe, many similarities actually exist. This article will examine in some detail how these issues manifest themselves in three geographic regions: the Western USA, especially the Central Valley of California; northwest Mexico, especially the Comarca Lagunera and Costa de Hermosillo; and the Aral Sea region of the Central Asian Republics of the Soviet Union. These case studies show that, in order to improve water management and use patterns, we must learn from past experience, utilize available information effectively, and avoid making the same old mistakes. One lesson from the past is very clear: without appropriate policy and institutional adjustments, no technical or engineering fix will succeed.     

北京地下水水权市场建设问题思考

北京水资源供需矛盾突出,局部地下水处于超采状态,用水结构不断发生变化,且需水量日渐增加。地下水权交易市场的建立可以缓解地下水超采的压力,有效地对水资源进行二次配置,极大地促进社会经济可持续发展。在分析国内外水权交易实践的基础上,结合我国具体的地下水利用特征,分析地下水水权交易过程中值得注意和完善的关键问题,为北京地下水水资源管理和地下水水权交易市场的发展提供参考。     

Groundwater Management for Sustainable Development of Urban and Rural Areas in Extremely Arid Regions: A Case Study

In Saudi Arabia, the recharge to local and regional aquifers is mostly indirect, very limited and insignificant, especially with low annual precipitation. Most of the stored groundwater in local and regional aquifers is non-renewable fossil water. With rapid socio-economic developments and increasing population coupled with agricultural and industrial growth in the Kingdom, especially after the large increase in oil revenues after 1974, the water demands have increased drastically. By understanding the aquifer features, the country followed a planned approach based on controlling aquifer development and demand management to use its groundwater resources. The socio-economic developments in rural areas have been very pronounced. Corrective demand management measures including reduction in cultivated areas and modification in agricultural support policies in addition to the augmentation of water supplies by the reuse of treated wastewater have reduced the stress on groundwater. The establishment of a special Ministry for water and the adoption of a national water planning approach and the use of an integrated water resources management tool are expected to contribute effectively to the achievement of sustainable groundwater resources and the national interest of the country.     

小塔山水库水资源配置及保障措施研究

在小塔山水库可供水量分析基础上,合理规划配置小塔山水库供水量,并制定供水分配原则及方案。针对农灌用水不足的问题,从增加小塔山水库蓄水量、推广农灌节水、加强小塔山水库外来水补给以及水库运行管理等多方面采取相应措施予以保障。通过对小塔山水库水资源合理配置,可实现小塔山水库水资源的可持续利用,在充分保障赣榆区居民生活用水的同时,也满足农灌用水基本需求,有效解决生活用水和农灌用水争水矛盾问题。     

江苏省农业节水问题研究

分析了江苏省水资源的特点 ,指出发展节水灌溉可以提高水资源和土地利用率 ,缓解水资源供需矛盾 ,促进农业可持续发展。提出江苏省发展农业节水的主要途径为加强渠道防渗 ,推广水稻节水高效灌溉技术 ,发展沟灌、畦灌、喷灌、微灌地膜覆盖栽培技术。提出为加快节水农业的发展 ,必须依法治水 ,广泛筹集资金 ,改革水利工程管理体制 ,加大科技投入 ,理顺水费价格。     

提高灌溉水利用系数，保障国家粮食安全与水安全

针对我国粮食生产面临的巨大挑战以及日益尖锐的农业用水供需矛盾,分析我国灌溉水利用现状,提出提高灌溉水利用系数的工程、技术和管理措施,旨在为我国缓解水资源供需矛盾,保障国家粮食安全,实现水资源的可持续利用提供借鉴。     

基于模拟技术的灌区水资源供需平衡分析

利用系统工程的思想,建立灌区水资源需水计算的数字模拟模型,并对都江堰灌区水资源开发利用现状及灌区水资源供需平衡进行了分析。以都江堰灌区为例,将灌区分为若干子区,分析该流域的供水能力、供需现状及供需发展情况。讨论各规划水平年水源工程和解决分区内水资源紧缺问题。     

ET管理是农业节水灌溉水资源管理的方向

ET是蒸发蒸腾耗水量的代号。ET管理即采取工程的、农业的和管理的综合节水措施,把节水灌溉项目区的耗水量控制在包括降水在内的水资源许可的范围内,实现水资源供耗平衡,可持续利用的目标。介绍了世行贷款项目农业节水灌溉一期项目实施ET管理概况及取得的主要成果。     

白山市农村土地整治工程水资源 供需平衡分析

土地整治的重要影响因素是水资源,作为粮食生产支撑的水资源供需平衡分析是工程建设的重要环节和技术保障。经过需水量和供水量的计算,白山市整体推进农村土地整治示范建设重大工程项目区多年平均水资源可利用量为899.01万m3/年。预测2015年需水量为555.24万m3,其中生活需水量416.52万m3;农业灌溉需水量为138.72万m3。研究结果表明： 供水量大于需水量,全区水资源略有盈余,各项目区在设计供水工程条件下,基本可以达到供需平衡。     

再生水灌溉研究进展

从再生水灌溉对土壤、作物、地下水和土壤斥水性4个方面简述国内外再生水灌溉的发展概况和研究进展。已有研究表明：再生水灌溉对土壤肥力和土壤酶活性的影响尚未有定论;再生水对农作物生长的影响尚有分歧;再生水灌溉对地下水水质具有一定的影响,并显著影响地下水水环境;长期的再生水灌溉会引发土壤斥水性的产生,且土壤斥水持续时间与土壤有机质质量分数呈正相关。目前存在的问题有：再生水灌溉对土壤和农作物的影响研究不一致,如何消除再生水灌水对地下水和土壤斥水性的影响。认为由于再生水中含有作物正常生长的必要营养元素,若能克服再生水灌溉存在的问题,可缓解淡水资源的压力和减少化肥的使用,避免环境的污染。     

干旱缺水区民勤县水资源持续高效利用措施研究

采用调查研究和统计分析方法,对民勤县石羊河流域重点治理工程及其效益得以显现的关键技术管理措施和效果进行调查研究。结果表明,指标层层细化、"三水"联合调度、轮次定额配水、推行差别水价政策、推广节水技术、调整农业种植结构、落实责任等措施,是实现水资源严格管理和高效利用的有效措施;责任制度落实、层层监督检查是水资源精细化管理的有效行政推动措施;乡(镇)水资源管理办公室是水源配置方案有效落实的重要组织保障措施;采用计量监控、监测设施设备是水资源管理的有效管控手段;依据水权和农产品动态趋势,适时调整农业种植结构,逐步形成以水定布局、节水高效的动态种植结构模式,是巩固水资源管理成果、推动水资源持续利用效益再上台阶的有效途径;以滴灌为主的高新高效技术推广和设施农牧业的高效发展是干旱缺水区缓减水资源供需矛盾、持续高效利用有限水资源和巩固流域生态修复成果、促进生态环境趋于良性循环的战略措施。