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.

Geological conditions and key rock mechanics issues in the Western Route of South-to-North Water Transfer Project

In terms of special geological conditions of the Western Route of South-to-North Water Transfer Project, the classification method for surrounding rocks is discussed by combining with the construction method of tunnel boring machine （TBM）. The classification standard of surrounding rocks is put forward on the basis of physical simulations and engineering practices. Damage, deformation and evolution of surrounding rocks induced by TBM excavation are discussed. Meanwhile, the long-term deformation mechanisms and stability of surrounding rocks are also studied. On this basis, a three-dimensional constitutive model for interbedded sandstone slate and a fiat shell-joint element-foundation system for calculating internal forces of segment lining are established. The deformation features of surrounding rocks of deep and steep interbedded sandstone slate and their influences on internal forces of segment lining are presented. Finally, the design methods of segment lining constructed in deep and steep flysch are proposed.

Price Analysis of Water Supply for South-to-North Water Transfer Project

The factors influencing the water supply price of a hydraulic project include natural conditions and economic policies. This paper thoroughly demonstrates the water price of South-to-North Water Transfer Project from the viewpoint of economic policies. It is considered that if the project is assigned as a profitable one and built depending on commercial loan from bank completely or mostly, the water price will be too high to be undertaken by users,and if the project places the public good at first while considering the economic benefit, its investment mainly relies on the state (national or local governments) appropriation and self-raised funds and a little from the bank loan on favorable terms, the price determined according to the principle of satisfying the cost and reasonable profit will be relatively lower and can be undertaken by the users in the North China where water shortage is serious. The problem of higher water price of agricultural irrigation to the north of the Yellow River can be tackled by taking measures such as "compensating agriculture by industry" according to foreign practical experiences and relevant suggestions.

Simulation of Transport Channel in China's Middle Route South-to-North Water Transfer Project

The unsteady flow in the Middle Route South-to-North Water Transfer Channel was simulated numerically using an implicit solution procedure for the Saint Venant equations. An equivalent roughness was used to simulate the effect of many transfer structures on the water levels in the main channel. Various gate operating and control methods were analyzed to study the response to disturbances produced by varying the flow rates through the Tianjin outlet. The results show that when the inflow at the head changes in the same way as the sum of the flow rates through all the outlets, the transition time and the fluctuation of the water levels using the timed gate operation method are less than when using the simultaneous gate operation method, but the variations of the gate openings and flow rates through each control gate are much larger. The flow disturbances produced by the Tianjin outlet can be rectified within several channel sections and the transition time can be greatly shortened by allowing the water levels immediately upstream of the control gates to vary within proscribed ranges, rather than being held constant.

Coupling interaction between biodiversity and aquatic habitat area in Western Route Project vicinity

The Western Route of the South-to-North Water Transfer Project will divert water from the upper Yangtze River and its tributaries, the Dadu River and Yalong River, to the upper Yellow River. The project may ease the water shortage in the Yellow River Basin. However, it may also have some effects on the ecosystem in the upper Yangtze River Basin. Benthic invertebrates play an important role in the river ecosystem, particularly in the circulation of materials and nutrition. Benthic invertebrates are widely used to quickly assess river ecosystems because of their rapid response to changes in the water environment. The diversity of benthic invertebrates is closely associated with the aquatic habitat area. This study examined this interaction by sampling the benthic invertebrates in an expanding area. The conclusions are that the diversity of benthic invertebrates begins to decrease when the aquatic habitat area is reduced to 45% of the original area, and decreases dramatically when the aquatic habitat area is reduced to 10% of the original area. The aquatic habitat area should be kept at more than 45% of the original area in order to maintain the significant diversity of benthic invertebrates.

南水北调中线工程核心水源区石漠化治理探讨

淅川县是南水北调中线工程渠首和核心水源区,境内有亚洲第1大人工水库丹江口水库,生态区位十分重要,由于水源区周围的山体主要是喀斯特地貌,土壤脊薄,植被稀少,石漠化问题十分突出。为担起一库清水送京津的重任,治理石漠化迫在眉睫。2016年以来,淅川县根据不同石漠化类型,通过人工造林、飞播造林、封山育林、退化林修复等多种方式进行综合治理,积累了丰富的经验,为石漠化地区石漠化治理提供参考。

引江补汉工程实施后的南水北调中线水源工程可调水量分析

随着新时期南水北调后续工程的高质量发展,首批建设工程引江补汉工程正式开工,为支撑未来南水北调中线水源工程与引江补汉工程的联合协调运行,根据引江补汉工程设计参数,提出多组丹江口水库与引江补汉工程联合调度方式,并模拟分析得到引江补汉工程实施后南水北调中线水源工程可调水量具有重要意义。研究结果表明:设置引江补汉工程补水水位控制线、同步优化陶岔渠首引水调度线,充分利用引江补汉工程补水来满足汉江中下游用水需求,从而置换更多坝前水量引至陶岔渠首、清泉沟等用水需求方,可在一定程度上实现丹江口水库供水与引江补汉工程补水决策的有效衔接;相比于中线一期工程现状供水调度情景,采用合适的引江补汉工程与中线水源工程联合调度方式,可在保障汉江中下游用水量需求的同时,满足下游断面最小用水量达标率至98.9%~99.2%,并提高中线受水区可供水量17.7亿~25.8亿m^(3),继而有效协调中线水源工程的中线受水区、清泉沟渠首及汉江中下游等多方用水需求。

南水北调中线干渠闸门同步关闭水力响应特性

构建南水北调中线干渠局部一维非恒定渐变流模型,以“刁河闸—湍河闸”渠池为例,测试闸门调控方式和渠道运行条件对闸前壅水峰值水位、达到峰值水位所用时间、水力振荡频率、水力振荡幅度等水力响应特性的影响。研究表明:水力振荡上升过程快,下降过程慢,波幅随时间呈对数函数衰减;闸前壅水峰值水位随闸门关闭速度、闸门关闭幅度、输水流量、运行水位、渠道糙率的减小而近似线性地减小;达到峰值水位所用时间对输水流量、运行水位和糙率变化不敏感,随闸门关闭幅度和输水流量的增加而近似线性减小;水力振荡频率对闸门关闭所用时间、闸门关闭幅度、输水流量和糙率变化不敏感;水力振荡幅度对运行水位、糙率变化不敏感,随输水流量的增大而快速衰减。

南水北调中线工程水资源市场联动定价配置机制研究

配置机制是影响水资源配置效率的关键因素之一,为进一步提高南水北调中线工程水资源配置效率,采用均衡分析方法,探讨了目前配置机制存在的内生节水激励不足、市场均衡难以实现、水资源稀缺性体现不充分、市场化生态补偿机制不健全等问题,提出了包含供给侧市场、需求侧市场、受水区同一地级市内水权交易市场、受水区不同地级市间水权交易市场的南水北调中线工程水资源市场联动定价配置机制,并分析了各市场的运作机制及价格联动机制。为规避市场机制失灵,从政府监管和工程技术支持两个方面提出了新机制有效运行的保障措施。

水面光伏抑制蒸发作用对应节水量的优化配置--以白洋淀湿地补水为例

水面光伏可通过组件等的遮挡作用减少建设水域蒸发损失,规模开发后形成显著的抑制蒸发的节水潜力,如何再配置上述节水量以实现最佳水资源利用是亟待解决的问题。基于此,结合湿地生态补水问题,以湿地优势物种价值增量最大、湿地水资源保障能力增量最大和水源地用水效益损失最小为目标,构建水面光伏抑制蒸发作用对应节水量的优化配置模型,并以典型湿地——白洋淀进行案例分析。结果表明:水面光伏抑制蒸发的节水可在改善湿地生态补水工作中发挥关键作用。白洋淀低、中和高补水需求下,芦苇经济价值最大增加0.5亿、2.6亿和5.5亿元,水资源保障能力提高61%、42%和28%,丹江口水库在丰水年、平水年和枯水年的平均最小发电损失为0.25亿、0.38亿和0.43亿kW·h。白洋淀补水需求和丹江口水库来水的不同遭遇情景的配置方案表明:白洋淀在低补水需求时,建议高流量补水时段为3—6月和9月;在白洋淀中、高补水需求时,建议高流量补水时段为10月—次年2月或3—6月。

南水北调中线工程沿线区域创新合作的共生机制与模式

区域创新合作主体由合作创新而产生了关联,随着合作的延续与深入,信任关系不断加深,创新合作网络将向共生合作网络演进。研究从南水北调中线工程沿线区域创新合作入手,对南水北调中线工程沿线区域创新合作机制以及合作模式进行分析。运用扎根理论进行系统探索,辨识和提取共生要素,构筑其共生合作机制,同时构建了产业链、创新链、资金链、人才链、生态链五链融合合作模式体系,以期对南水北调跨流域创新合作带来新的启示。

南水北调中线工程水位的水动力-神经网络耦合预测模型

南水北调中线工程通常以闸前常水位调度运行,而水位在闸门调控影响下多数处于非平稳状态,探索其变化规律对于监测数据和研究方法均有一定限制和要求。监测数据方面,针对大量的高频监测数据选取均值滤波、滑动平均值滤波、递推中位值平均滤波法、滑动小波变换进行数据预处理,提高数据质量、增强数据预测的可行性。研究方法层面,以BP神经网络模型和长短期记忆(long short-term memory,LSTM)网络模型为主体框架,以水动力模型的模拟数据为辅助支撑,对比单神经网络在不同工况下的预测效果,输出水动力-神经网络组合预测结果。结果表明:数据预处理是数据分析和预测的必要环节,高频数据滤波处理再预测可以提高数据预测的精度;均值滤波、递推中位数均值滤波方式对数据预处理的效果最好,指标合理时滤后决定系数(R^(2))精度均超过0.95,且均方根误差(RMSE)和平均绝对误差(MAE)不超过0.02,准确性高;基于滤后数据进行模型构建,通过对比数据驱动模型和数据-机理双重驱动模型的计算结果,R^(2)维持在0.98附近,RMSE、MAE维持在0.01左右,耦合模型具有更好的稳定性和准确性。

超标准暴雨洪水条件下南水北调中线工程沿线各单元风险评估

对南水北调中线工程沿线639个单元工程风险进行评估,并对灌渠河、贾河、金水河、石门河和沙沟5个典型单元进行重点分析。结果表明:中线工程沿线639个评估单元中,风险事件可能性指数为1的单元占比最大,风险等级以一般风险为主;在5个典型单元中,极端降雨移用(植)后在交叉断面处形成的洪水基本上呈现流域面积越小洪水量级越大的特点。此外,灌渠河排水倒虹吸发生渠顶漫溢的风险低;贾河梁式渡槽、沙沟排洪渡槽和石门河渠道倒虹吸均存在较高的工程风险;金水河渠道倒虹吸在超标准洪水下河道冲刷满足要求,工程风险较低。研究成果对提前部署南水北调中线工程防御超标准暴雨洪水具有指导意义。

南水北调中线工程水体溶解性有机质分子组成特征

为揭示南水北调中线工程水体中溶解性有机质(Dissolved Organic Matter,DOM)的组成变化特征,采集南水北调中线总干渠沿线及丹江口水库水样,利用傅里叶变换离子回旋共振质谱(Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,FT-ICR MS)分析了DOM的分子组成及其空间变化,并探讨了总干渠沿线DOM变化成因和环境意义。结果表明:丹江口水库和总干渠均检出DOM物质3200余种,仅含C、H和O的物质(CHOs)为主要组分,约占所有检出物质的61%,含C、H、O和N的物质(CHONs)占30.5%~31.5%,含C、H、O和S的物质(CHOSs)仅占7.3%~8.4%,结合O/C和H/C分类,丹江口水库和总干渠水体DOM主要组分为木质素(60%以上)。相较于丹江口水库,总干渠水体DOM组分发生了较大变化,蛋白质类组分占比由3.70%升至8.65%,表明总干渠中有蛋白质生成;稠环类物质占比由9.43%下降至4.77%,单宁酸类的变化趋势与稠环类物质类似。总干渠局部区域藻类增殖过程是引起总干渠中CHONs和CHOSs类DOM组分和占比升高的主要原因。研究成果可为科学认识南水北调中线工程水体水质变化过程提供科学依据。

智慧水资源管理与调配应用评价指标体系构建

为了推进智慧水资源管理与调配应用的发展,根据水利业务应用中预报、预警、预演、预案的特点,按照可获取性、可量测性、可代表性的原则,结合《“十四五”智慧水利建设规划》中水资源管理与调配应用的主要内容,构建由3个一级指标、9个二级指标和24个三级指标构成的智慧水资源管理与调配应用评价指标体系,提出指标计算方法,并对南水北调中线工程进行实例研究。结果表明,南水北调中线工程智慧水资源管理与调配应用的总得分为84.9分,为良好等级,一级指标中水资源管理应用得分最高,为95.3分,水资源调度应用得分为81.5分,数字化场景应用得分偏低,为70.8分,亟需改进。

数字孪生南水北调中线工程建设思路

南水北调工程受限于当时规划设计和信息化总体建设水平,存在输水调度不能与沿线受水区实现供需最优配置,水质监测自动预警程度不高、水污染突发事件应急处置缺乏科学决策支持及工程安全风险不能主动精准预警等问题。为解决上述问题,基于南水北调中线工程的建设现状和数字孪生技术特点,从框架设计、技术路线规划2个方面提出数字孪生南水北调中线工程的总体建设思路,并且围绕工程安全、供水安全、水质安全的“四预”需求,详细阐述实施路径和重点建设内容,为数字孪生南水北调中线工程建设提供重要参考。

南水北调中线工程总干渠冬季大流量输水水温调控措施

为保障南水北调中线工程冬季输水安全,利用建立的总干渠全线一维水温模型,针对350、280、210和150 m3/s这4种不同输水流量方案,模拟分析各方案在强冷冬、冷冬、平冬和暖冬等典型冬季气象条件下总干渠冬季输水保温效果,在此基础上提出总干渠冬季无冰盖大流量输水水温调控措施。结果表明:针对不同典型冬季气象条件,在有限条件下采取无冰盖大流量输水调度运行方式,可不同程度缩短输水流动时长、减少沿程水体热量损失,从而达到保温效果;在各典型冬季年份气象条件下,随着总干渠输水流量增大,沿程水温比降相应减缓,明渠末端水温相应提升;在冬季气象条件适宜情况下,总干渠冬季采取无冰盖大流量输水水温调控措施,既有利于减小水温降幅,同时也可有效解决冬季输水能力受限问题;建议根据总干渠中短期气温预报和水温预测情况,在冷冬、平冬和暖冬等典型冬季气象条件下尽可能采取较大输水流量输水模式,在强冷冬气象条件下可分时段、分渠段采用无冰盖大流量输水模式。

南水北调中线水源地农业面源污染时空演化特征

基于清单分析法对2010—2019年南水北调中线水源地农业面源污染物TN和TP的排放量进行测算,并结合ArcGIS软件对其时空演变特征进行分析。结果表明:2010—2019年,南水北调中线水源地农业面源污染物TN负荷和TP负荷整体上呈现先增加后减少的趋势;TN和TP污染强度呈先升后降趋势;化肥、畜禽养殖和农村生活是水源地农业面源污染TN和TP负荷的主要来源,且化肥比重缓慢增加,畜禽养殖比重不断下降,农村生活比重不断增加。研究结果可为中线水源地农业面源污染治理、生态保护等方面政策及措施的制定提供决策支持。

南水北调中线工程河南省受水城市地下水生态系统服务价值评估

选取南水北调中线工程河南省受水城市为典型研究区域,综合运用市场价值法、替代工程法和等效替代法等对南水北调中线工程河南省受水城市2008—2019年地下水生态系统服务价值进行评估。结果表明:河南省11个受水城市中,地下水生态系统服务价值最高的是郑州市,变化较为稳定的是平顶山市、漯河市和许昌市,变化最剧烈的是鹤壁市。郑州市2019年地下水生态系统服务价值为213.17亿元,其中,调节服务价值最高,支持服务和供给服务价值次之,社会服务价值最低;在各指标中水源涵养指标占总价值比例最高,预防地面沉降指标次之,科研教育指标占比最小。河南省受水城市2008—2019年多年平均生态系统服务价值为1030.37亿元,变化趋势为先下降后上升,转折点出现在2013年,原因是地下水压采、南水北调中线工程置换地下水、植树造林、水土保持等措施增加了地下水资源量。研究结果可为南水北调中线工程受水城市生态环境效益评价及地下水保护提供参考依据。