Land Cover Changes and Drivers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China from 2000 to 2015

The Middle Route of the South-to-North Water Diversion Project(MR-SNWDP)in China,with construction beginning in 2003,diverts water from Danjiangkou Reservoir to North China for residential,agriculture and industrial use.The water source area of the MR-SNWDP is the region that is most sensitive to and most affected by the construction of this water diversion project.In this study,we used Landsat Thematic Mapper(TM)and HJ-1 A/B images from 2000 to 2015 by an object-based approach with a hierarchical classification method for mapping land cover in the water source area.The changes in land cover were illuminated by transfer matrixes,single dynamic degree,slope zones and fractional vegetation cover(FVC).The results indicated that the area of cropland decreased by 31%and was replaced mainly by shrub over the past 15 years,whereas forest and settlements showed continuous increases of 29.2% and 77.7%,respectively.The changes in cropland were obvious in all slope zones and decreased most remarkably(–43.8%)in the slope zone above 25°.Compared to the FVC of forest and shrub,significant improvement was exhibited in the FVC of grassland,with a growth rate of 16.6%.We concluded that local policies,including economic development,water conservation and immigration resulting from the construction of the MR-SNWDP,were the main drivers of land cover changes;notably,they stimulated the substantial and rapid expansion of settlements,doubled the wetlands and drove the transformation from cropland to settlements in immigration areas.

Eco-environmental benefit assessment of China's South-North Water Transfer Scheme——the middle route project

This paper assess the eco-environmental benefits that may come from the middle route project of China's South-North Water Transfer Scheme(SNWT) with principles and methods of eco-economics and planning reports of SNWT's middle route project. Some benefits were calculated in monetary units. To make sure that the results can be comparable with normal monetary indices, concrete assessment objects and the parameters are prudently selected according to the major characteristics of the project and its water import region. Primary assessment revealed that in different project construction stages, the benefit could be more than 13 07 billion RMB Yuan in 2010 and 19 79 billion RMB Yuan in 2030, respectively. The monetary value tends to increase with social-economic development. To realize these potential benefits, however, calls for more endeavors.

Water-saving potential evaluation of water-receiving regions in Shandong province on the East Route of the South-to-North Water Transfer Project of China

Taking 13 water-receiving areas on the East Route of the South-to-North Water Diversion Project(ERSNWDP)in Shandong Province as the study area,and comparing it with Jiangsu Province on the ERSNWDP and the Middle Route of the South-to-North(MRSNWDP),the current water-saving potential of the water-receiving areas within the municipalities of Shandong was analyzed.Different water-saving scenarios were constructed and analyzed with key water-saving indexes in various industries.These indexes include the effective utilization coefficient of farmland irrigation water,total water consumption of industrial sectors with an added value of over 10000 RMB,average leakage rate of the urban public water supply pipe network and the penetration rate of water-saving appliances.Based on the scenarios,comprehensive water-saving potential of the 13 water-receiving area cities was calculated.The results show that the water-saving potential of the study area is at a relative high level.However,some cities still have a certain amount of water-saving potential for agriculture and industry to be elevated.Under the recommended water-saving scenario,the water-saving potential is 1.134 billion m3,accounting for 5.33%of the current total water consumption,of which 460 million m3 is in agriculture,600 million m3 in industry,is and 74.20 million m3 in urban domestic sector.Comprehensive water-saving measures for the study area were proposed from the aspects of agricultural,industrial and domestic water uses.Agricultural and industrial water saving are more significant.The major cities for agricultural water saving include Jining City,Heze City,Weifang City and Jinan City;the focus cities of industrial water saving mainly include Weihai City,Jining City and Qingdao City and etc.;the key water-saving areas for urban use mainly include Zaozhuang City,Jining City and Heze City.

Potential Ecological Benefits of the Middle Route for the South-North Water Diversion Project

This paper presents a study of the middle route of the South-North Water Diversion Project. The middle route runs through the Northern China plain, where the water shortages are the most severe. There is not only a shortage of water for human usage, but also a shortage of ecological water. Although the current plan for the middle route is strictly focused on supplying water for residential and industrial use, the water can also potentially be used for ecological purposes. This paper evaluates the potential ecological benefits that can be brought to the fragile ecology in northern China by the middle route, in addition to the water supplied to residences and industry. The study describes ecological benefits of the middle route project, such as mitigation of groundwater extraction in the region and positive influences on the climate, the ecological uses of the middle route project itself, such as creating artificial niches along the channel and directly using the channel for ecological purposes, and the ecological uses of the water along the middle route such as diversion of the water into dyer channels that have suffered from drought conditions for decades.

On conservation and development of architecture and environment in the construction of large-scale national infrastructure——Exemplified by the Jiangsu Section of the Eastern Route South-to-North Water Diversion Project

The water-diverting route project’s characteristics,natural landscapes,and histories and humanism of the Jiangsu Section of the Eastern Route South-to-North Water Diversion Project were systemically analyzed through proposing and studying the canal culture routes,the water resources heritage corridors,the landscape and recreation corridors,and the town economic corridors.The station areas along the water-diverting route were scientifically zoned and graded through quantitative and qualitative synthetic methods.Both planning compendiums and construction controlling methods were proposed based on the project grades of points,lines,and areas.Conservation and development of architecture and environment in the large-scale national infrastructure construction were explored systemically.Theories and methods of developing harmonious water-supplying functions,ecological functions,landscape effects,and cultural effects of large-scale water resources were examined.

Computing payment for ecosystem services in watersheds: An analysis of the Middle Route Project of South-to-North Water Diversion in China

Payment for ecosystem services （PES） has attracted considerable attention as an economic incentive for promoting natural resource management recently. As emphasis has been placed on using the incentive-based mechanism by the central government, rapid progress on PES research and practice has been achieved. However PES still faces many difficulties. A key issue is the lack of a fully-fledged theory and method to clearly define the design scope, accounting and feasibility of PES criteria. An improved watershed criteria model was developed in light of research on PES practices in China, investigations on the water source area for the Middle Route Project of South-to-North Water Diversion and ecosystem services outflows theory. The basic principle of assessment is the direct and opportunity cost for ecological conservation and environmental protection in the water source area deduct nationally-financed PES and internal effect. Then the scope and the criteria methods were determined, and internal effect was put forward to define benefits brought from water source area. Finally, Shiyan City, which is the main water source area for the Project of Water Diversion, was analyzed by this model and its payment was calculated. The results showed that： （1） during 2003–2050, the total direct cost and opportunity cost would reach up to 262.70 billion and 256.33 billion Chinese Yuan （CNY, 2000 constant prices）, i.e., 50.61% and 49.38% of total cost, respectively; （2） Shiyan City would gain 0.23, 0.06 and 0.03 CNY/m3 in 2014–2020, 2021–2030, and 2031–2050, respectively.

南水北调西线工程水源区可调水量“十问”

南水北调西线工程是我国“四横三纵”国家水网主骨架尚待建设的最后一环,而水源区可调水量是西线工程规划论证面临的焦点和难点问题。本文从水资源本底条件与演变趋势,生态环境与经济社会发展需水,调蓄水库与输水工程规模,调水对水源区及其下游水资源开发利用、水生态环境、水力发电、航运等方面影响的角度,提出了与水源区可调水量相关的10个问题;以长江上游分布式水文模型为基础,建立了南水北调西线工程水源区可调水量模拟分析模型,力图系统、定量地回答所提问题。本文的主要研究结论有:在仅考虑满足水源区河道内外生态环境和经济社会需水的前提下,“上线+下线”组合方案多年平均可调水量为1.59×10^(10)m^(3),“完全下线”方案在建设岗托水库进行联调时,多年平均可调水量将达到1.74×10^(10)m^(3);在综合考虑调水对水源区水平衡、水力发电和航运影响及其可接受程度后,南水北调西线水源区可调水量为1.22×10^(10)~1.26×10^(10)m^(3)。长远来看,应谋划西南片区水网与国家水网主骨架、“大动脉”的连接与融合,在减小南水北调西线工程调水影响的同时,提高南水北调西线工程的整体供水能力以及对气候变化等外部条件的适应性。

局部降温对输水渠道水华抑制的影响分析

南水北调中线工程自通水以来,发挥着巨大的社会和经济效益,已成为京津地区的主力水源。中线工程输水的水质理化指标相对稳定,但局部渠段存在藻类异常增殖现象,有水华爆发的风险。针对出现的藻类异常增殖问题,在通冷风这一改变局部气象条件的工程措施基础上,建立了澎河—沙河渡槽段平面二维水动力和水质模型,研究了通风位置、通风温度和通风时长等因素对输水渠道水温和藻类的影响。研究表明:水温和叶绿素a浓度均与通风位置、通风温度和通风时长有关,通风温度越低、通风时长越长,平均水温和叶绿素a浓度下降幅度越大,平均水温最高可下降约2℃,叶绿素a浓度最大可降低约54.5%,且仅上游和全渠段通风均可有效降低水温和抑制藻类生长,仅下游通风对水温和藻类的影响较小。因此,采取局部降温的方式可以起到一定的降低叶绿素a浓度的作用,综合考虑藻类抑制效果和工程成本,在水华易爆发渠段的上游通冷风是行之有效的工程措施。

南水北调中线水源区植被指数时空变化分析

通过单线性回归(SLOPE)和地理加权回归(GWR)法,用植被指数(NDVI)研究南水北调中线水源区的植被分布变化趋势及机制,为保障水量和水质提供理论支撑。结果表明,2000—2019年水源区NDVI和入库流量呈现同步增长,植被逐渐变好,2007年以前NDVI增长幅度大,2008—2011年处于波动阶段,2012年以后增长幅度减小;NDVI变化最明显的是研究区东北部、西部和丹江口库区周边,这些区域地势相对低平、人口集中,中山和高山区NDVI变化不大;高程、坡度、人口数和城镇化是影响水源区NDVI分布的主要因素,降水、气温和产业比重是次要因素;各因素影响的强度和方向在空间上有异质性,自然地理因素对NDVI影响的最显著范围为高程1090 m以下、年均降水量980 mm以上的区域,人文地理因素影响的显著范围区是人口密度大、城镇化率高的地区。

南水北调西线工程上线水源区大型底栖动物群落结构及环境驱动因子

为评估南水北调西线工程上线水源区大型底栖动物群落结构及环境驱动因子,于2022年7月(汛期)和11月(非汛期)开展监测采样工作。采用生物多样性指数和丰度-生物量比较曲线(ABC曲线)作为大型底栖动物群落特征参数,分析大型底栖动物群落在水源区的结构,并对其进行多元排序和Pearson相关性分析。结果表明:共采集45种大型底栖动物,隶属于4门5纲10目32科44属,其中优势种8种,所有优势物种出现频率均大于50%,水源区大型底栖动物群落结构一致性较高;水源区Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数均值分别为4.01、1.68、0.61;多数采样区域大型底栖动物的ABC曲线呈纠缠态势,其丰度和生物量累积百分比的差值面积在0附近波动,群落以小个头物种为主;优势种以耐污值低的敏感种类为主,说明河流几乎不受污染,水体清洁;pH值是影响水源区大型底栖动物群落结构的主要环境驱动因子。

基于多方法综合比较的南水北调西线工程水源区生态需水研究

针对南水北调西线工程调水需求,以方法比选、目标修正、可行性验证为主线,提出了一套多方法综合确定水源区生态需水过程的思路,并制定了10个坝址断面枯水期和非枯水期的生态基流、敏感生态需水及年生态水量目标。结果表明:水源区坝址断面枯水期生态基流在多年平均流量中的占比约为20%,非枯水期占比约为40%;3—6月为鱼类集中产卵敏感期,需要每月发生一次脉冲流量过程,每次至少持续10 d,脉冲流量在多年平均流量中的占比为48%~73%;各坝址断面年均生态水量在多年平均径流量中的占比约为70%,其中丰水年、一般偏枯年、枯水年生态水量占比分别为68%~78%、66%~75%和61%~70%;研究结果符合长江流域现有管控要求,具备较好的现实可达性。

南水北调中线工程水源区环境规制对经济高质量发展的影响

为研究南水北调中线工程水源区环境规制通过水资源利用对区域发展质效的影响,基于2005—2022年南水北调中线工程水源区12个城市的面板数据,构建基准回归模型、中介效应模型和门槛效应模型,实证分析了环境规制、水资源利用效率和经济高质量发展之间的关系。结果表明:环境规制对经济高质量发展具有正向促进效应,该促进效应在不同区域间存在异质性,环境规制的促进作用在用水量小的地区更加显著,而在用水量大的地区,丰富的水资源限制了环境规制对经济高质量发展的促进作用;在环境规制影响区域,水资源利用效率在经济高质量发展过程中发挥出显著的中介作用,水资源利用效率中介效应占环境规制总促进效应的比例为13.5%;水资源利用效率在环境规制对经济高质量发展影响中具有门槛效应,当水资源利用效率超过4.3后,环境规制对经济高质量发展的促进效应显著增强。

水上光伏覆盖对明渠水质的影响规律研究

水上光伏带来的太阳短波辐照度变化对缓解输水明渠藻类增殖问题的效果亟需评估。以南水北调中线干渠为例,建立干渠安阳河节制闸至坟庄河节制闸渠段的水动力和水质模型,分析比较明渠水面悬浮式覆盖水上光伏带来的太阳短波辐照度变化和水上光伏不同覆盖位置对渠道水温和水质的影响规律。研究表明:在开展水上光伏项目时,渠道接收的太阳短波辐照度降低会使得水温、藻生物量和溶解氧含量下降,营养盐含量有所上升。太阳短波辐照度降低50%后,藻生物量开始逐渐降低。在覆盖率和透射率一定的情况下,不同覆盖位置情景下对藻生物量的削减峰值区别较小。当太阳短波辐照度由高到低逐渐变化时,流速变化对藻生物量的影响幅度呈先升高后下降趋势。

高雷诺数下倒虹吸闸墩绕流水力特性

为研究倒虹吸出口闸墩绕流特性,以南水北调某典型倒虹吸为例,基于Flow3D软件建立倒虹吸模型,根据现场原型实测水位、流速进行模型验证;利用该模型模拟了雷诺数6.17×10^(6)~9.38×10^(6)范围下闸墩绕流特性。结果表明,高雷诺数条件下,随着雷诺数的增加,闸墩绕流造成的液面波动幅度增加,中墩液面波动显著大于边墩;闸墩后的尾涡量持续增加,雷诺数对斯特劳哈尔数影响不大;边侧闸墩受力的非对称性明显,边墩闸室间特征流速偏流比存在先增大再减小的变化规律,偏流效应造成的离心距不断增加。本研究可针对性改善输水工程水流流态。

南水北调中线工程输水建筑物整流累积效应研究

为分析输水建筑物整流对南水北调中线工程输水能力的影响,以陶岔渠首闸至十二里河渡槽渠段为例,建立一二维耦合水动力模型,其中渠道段采用一维模型,4个输水建筑物段(刁河渡槽、湍河渡槽、严陵河渡槽和淇河倒虹吸)采用二维模型,利用多年实测数据对耦合模型进行率定。分别对无整流方案和15种整流方案进行模拟计算,分析不同整流方案对上下游的影响,进而确定水头损失最小的整流方案。结果表明:单体整流影响范围为建筑物上下游3~5 km,多个建筑物整流的累积效果小于单个建筑物整流效果的线性叠加;对渠段中间2个输水建筑物(湍河渡槽、严陵河渡槽)进行整流的效果优于对上下游2个输水建筑物(刁河渡槽、淇河倒虹吸)进行整流的效果。

南水北调中线工程水源区和受水区的降水时空变化特征及丰枯遭遇

[目的]基于1950—2022年时间序列ERA5再分析降水数据,探究南水北调中线工程水源区和受水区降水量时空变化特征,旨在保障跨流域调水的可行性和持续性,为南水北调中线工程水资源调度和运行管理提供科学参考。[方法]采用Mann-Kendall检验、小波分析、云模型以及Copula函数等方法,分析水源区和受水区降水变化趋势以及丰枯遭遇特征。[结果]①1950—2022年南水北调工程水源区和受水区分别按照年降水量34.75和39.35mm/(10a)幅度减少,水源区年降水量存在43a的主周期,受水区年降水量存在55a的主周期。②云模型隶属云图夏季降水量分布不均且离散程度较高,而冬季分布均匀且较集中。③调水不利的组合汛期和非汛期遭遇频率分别为23.15%和25.92%。[结论]水源区和受水区年降水量均呈现明显减少趋势,水源区丰枯交替变化显著;南北丰枯异步概率大于丰枯同步,同枯频率不高,有利于调水工程的安全性和可靠性。研究结果可为制定南水北调中线工程相关政策和技术指导提供理论依据,有助于工程的规划和管理,提高水资源利用效率和可持续性。

新形势下南水北调中线工程智慧调度的研究框架思考

南水北调中线工程智慧调度是新形势下实现精确精准调水、支撑工程高质量发展的重要途径。系统分析了南水北调中线工程通水以来的运行条件变化,提出了新形势下中线工程智慧调度需解决的关键科学技术问题,并提出了未来重点研究内容:要在研究复杂调水系统多水源多用户水资源均衡调配方法基础上,研发中线工程多场景输水智慧调控技术、事故智能预警与精细控制技术体系、决策支持平台,形成中线工程调度的科学决策管理模式,为国家水网重大工程智慧调度管理提供科学应用范式。

基于HHO的跨流域调水工程受水区水资源优化配置研究

跨流域调水工程是解决我国水资源时空分布不均和缓解水资源供需矛盾的重要措施。山东省黄水东调工程、引黄济青工程和胶东调水工程是缓解胶东地区潍坊、青岛、烟台、威海四市水资源紧缺问题的重要跨流域调水工程。为充分发挥调水工程社会和经济效益,在考虑受水区缺水量、工程输水能力及沿途分水口门设计流量等基础上,以受水区四市综合缺水率最小和调水工程经济效益最大为双目标,构建了胶东地区跨流域调水工程水资源优化配置模型,采用哈里斯鹰优化算法(HHO)求得现状水平年和规划水平年在50%、75%和95%频率时3种不同目标协调机制(以综合缺水率最小为主导、以调水工程经济效益最大为主导及两目标均衡)16个分水口门的调水方案。结果表明:(1)通过调水工程调引黄河水和长江水,使四市缺水量大幅减少;(2)当经济效益目标所占比重越大时,计量水价越高的分水口门供水量越大;(3)从三个调水工程利用程度来看,黄水东调工程利用程度最高,其次为引黄济青工程和胶东调水工程。本文为山东省胶东地区跨流域调水工程的水资源配置提供了决策支持。

南水北调东线工程典型供排闸站施工导流分析研究

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南水北调中线工程突发水污染生态补偿机制研究

突发水污染已成为制约南水北调中线工程可持续调水的重大安全隐患,亟须解决南水北调中线工程突发水污染的生态补偿机制设计问题。针对应由中线局承担责任的南水北调中线干渠突发水污染场景,从多利益相关者合作视角出发,明确了中线局向纳污地政府提供生态补水的突发水污染生态补偿机制,基于合作博弈理论,构建了中线局与纳污地政府合作联盟的纳什议价模型,并以河南省邓州市为例开展研究,主要研究结果表明:①生态补水天数与纳污总损失呈现出显著的正向相关关系,且伴随纳污总损失逐步增大,中线局议价能力对补水天数的影响能力呈现出边际递减特征。②中线局生态补水成本与生态补水天数具有显著的正向关系,随着中线局议价能力的增强,生态补水成本的规模效益呈现一定的弱化趋势。③在一定的生态补水规模范围内,中线局与纳污地政府能够达成有效的合作联盟。