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.

IMPACTS OF THE SOUTH-TO-NORTH WATER DIVERSION PROJECTS (MIDDLE ROUTE)ON THE WATER ENVIRONMENT OF THE MIDDLE AND LOWER REACHES OF THE HANJIANG RIVER

In this paper, according to the rule of unbalanced sediment transport and the analysis of field data, different water diversion schemes were theoretically studied, including the erosion and sedimentation trend as well as their impacts on the environment of the middle and lower reaches of the Hanjiang River. The results showed that the 95×10 8m 3 water diversion scheme will cause less erosion and water level decrease than the 15×10 8m 3 water diversion scheme. Using a water diversion scheme of 95×10 8m 3, the decrease of water quantity can impact the river hydrodynamic regime substantially and the environments of the middle and lower reaches of the Hanjiang River will be greatly affected. It is therefore necessary to develop new water resources or build projects to meet the need of the environment and the needs for navigation.

Penalty model for delay of bidding section construction period in South-to-North Water Diversion Eastern Route Project from perspective of programs

According to the multi-project and program management theory, this paper analyzes the program generation principle and establishes a program based on progress goals. On the basis of the present situation of calculation of penalty for delay of the bidding section construction period with the critical path method, we studied the effects of contractor-induced delay of the bidding section construction period in detail, including the effects on the construction period of the bidding section itself, the earliest start times of the next bidding section and other subsequent bidding sections, and the construction period of the program, and then constructed a penalty model for delay of the bidding section construction period from the perspective of programs. Using the penalty model, we conducted a practical analysis of penalty for delay of the construction period of the Baoying station program in the South-to-North Water Diversion Project. The model can help determine the amount of penalty for delay of the construction period in bidding sections scientifically and reasonably,

Impact of the eastern water diversion from the south to the north project on the saltwater intrusion in the Changjiang Estuary in China

The south to the north project (WDP) on the saltwater intrusion in the Changjiang Estuary is studied by the improved three-dimensionai (3D) numerical model.The net unit width flux in the Changjiang Estuary as well as the sectional salt flux is calculated in the North Branch (NB),the South Branch (SB),the North Channel (NC),the South Channel (SC),the North Passage (NP) and the South Passage (SP),respectively.The net seaward water flux in the SB is reduced,and the net water flux spilling over from the NB to the SB is enhanced after the eastern WDP.Under the mean river discharge condition in the dry season,the net salt flux spilling over from the NB to the SB is increased by 2.09 t/s and 0.52 t/s during the spring and neap tides,respectively,due to the eastern WDP.The saltwater intrusion in the Changjiang Estuary is enhanced by the eastern WDP.Compared with that during the spring tide,the net water diversion ratio during the neap tide in the NC is smaller,and thus the enhancement of the saltwater intrusion by the eastern WDP is smaller in the NC,and larger in the NP and the SP.The tidally averaged surface salinity at the water intakes of the Dongfengxisha Reservoir,the Chenhang Reservoir and the Qingcaosha Reservoir rises both during the spring and neap tides.

Reliability model of organization management chain of South-to-North Water Diversion Project during construction period

In order to analyze the indispensability of the organization management chain of the South-to-North Water Diversion Project （SNWDP）, two basic forms （series connection state and mixed state of both series connection and parallel connection） of the organization management chain can be abstracted. The indispensability of each form has been studied and is described in this paper. Through analysis of the reliability of the two basic forms, reliability models of the organization management chain in the series connection state and the mixed state of both series connection and parallel connection have been set up.

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.

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.

LONG AND DEEP DIVERSION TUNNELS OF 1^(ST) STAGE PROJECT IN WEST ROUTE OF SOUTH-NORTH WATER TRANSFER PROJECT

West Route of South-North Water Transfer Project,situated in southeastern Qinghai-Tibet Plateau,is a giant project,which will deliver 17 billion m3 of water from the main stream and tributaries upstream of the Yangtze River to the upper reaches of the Yellow River. It is to be constructed in 3 stages, of which the 1st stage project includes delivering 4 billion m3 of water by gravity from two tributaries of Yalong River and three tributaries of Dadu River. The project consists of 5 dams,7 tunnels and a channel in series,with the dam height of 63～123 m and water transfer length of 260.3 km,of which the tunnels measure 244.1 km. The special climatic,environmental and geologic conditions make the project much more complicated in construction,especially 3 tunnels with the length longer than 50 km each create challenges to the technical requirements of engineering survey,design and construction.

Critical chain construction with multi-resource constraints based on portfolio technology in South-to-North Water Diversion Project

Recently, the critical chain study has become a hot issue in the project management research field. The construction of the critical chain with multi-resource constraints is a new research subject. According to the system analysis theory and project portfolio theory, this paper discusses the creation of project portfolios based on the similarity principle and gives the definition of priority in multi-resource allocation based on quantitative analysis. A model with multi-resource constraints, which can be applied to the critical chain construction of the A-bid section in the South-to-North Water Diversion Project, was proposed. Contrast analysis with the comprehensive treatment construction method and aggressive treatment construction method was carried out. This paper also makes suggestions for further research directions and subjects, which will be useful in improving the theories in relevant research fields.

Critical discharge at Datong for controlling operation of South-to-North Water Transfer Project in dry seasons

Previous research shows that there is a strong correlation between saltwater intrusion in the Yangtze Estuary and discharge at Datong. In the near future, the discharge of the Yangtze River during dry seasons will decrease due to the construction and operation of large water diversion projects, including the South-to-North Water Transfer Project, which will further exacerbate saltwater intrusion in the estuary. In this paper, a nested 1D river network model and a 2D saltwater numerical model are used to associate saltwater intrusion in the Yangtze Estuary with different values of discharge at Datong. It is concluded that 13 000 m3/s is the critical discharge at Datong for preventing saltwater intrusion and controlling the volume of water transferred by the South-to-North Water Transfer Project. Furthermore, based on the analysis of river discharge from Datong to Xuliujing and in consideration of the influence of all of the water diversion projects, operation schemes are proposed for the Eastern Route of the South-to-North Water Transfer Project for different hydrological years.

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.

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.

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.

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.

Application of SEDEA to evaluation of degree of harmony between water resources and economic development

This paper introduces the method of data envelopment analysis （DEA） for evaluation of the degree of harmony between water resources and economic development of the water conservancy area of China＇s South-to-North Water Diversion Project （SNWDP）. For this evaluation, a super-efficiency DEA （SEDEA） model was developed based on the super-efficiency method. To verify the applicability of the SEDEA model, both the SEDEA model and a normal-efficiency DEA （NEDEA） model were used to evaluate the degree of harmony between water resources and economic development of typical cities in the SNWDP water conservancy area. The results show that the SEDEA model ranks the degree of harmony of typical cities more efficiently than the NEDEA model, and thus can better evaluate the degree of harmony between water resources and economic development of different cities than the NEDEA model. Furthermore, the SEDEA model can be applied as an operational research tool in regional water resources management.

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。

南水北调东线一期工程受水区生态环境效益演变

研究南水北调东线一期工程通水以来受水区生态环境效益的演变态势,对南水北调后续工程高质量建设、加快构建国家水网以及促进工程综合效益发挥有决策参考作用。以定性定量相结合的方式分析东线一期工程在优化水资源配置、保障饮水安全、复苏河湖生态环境和畅通南北经济循环等方面的作用,进而结合层次分析法,从直接效益和间接效益2个方面,筛选构建东线一期工程受水区生态环境效益评价指标体系,主要包括工程年供水量、水质改善度、生态补水量、地下水压采量、地下水水位、水域面积、绿地面积和涵养水源等,并采用VlseKriterijumska Optimizacija I Kompromisno Resenje(VIKOR)多准则妥协解排序方法对南水北调东线一期工程通水以来即2013-2022年受水区生态环境效益演变态势进行分析。结果表明:南水北调东线一期工程通水的10年以来,受水区的生态环境整体复苏效果明显,近3年排序值保持在0.8以上;受降水偏枯进而影响地下水开采量和地下水水位等因素影响,2019年间接生态环境效益下降29.2%,之后迅速恢复并保持稳定。在分析直接效益和间接效益演变的基础上,从工程提质增效、提高工程水质状况以及完善体制机制建设等方面提出东线一期工程进一步促进受水区生态环境持续改善的策略和建议,以期为东线工程及受水区生态环境保护及高质量发展相关研究、决策制定等提供参考。

水网布局下黄河流域应对极端枯水的关键科学问题

变化环境下极端气象水文事件频发,长江、黄河面临同枯风险。在国家水网建设背景下,为提高长江、黄河同枯的极端不利情景下黄河流域水资源安全保障能力,本文分析了长江、黄河两大流域水资源安全面临的现实问题,识别了变化环境下大型流域枯水遭遇—水危机形成—跨流域调水潜力—多线路成网互济—极端枯水下水资源安全保障中亟需破解的关键科学问题,构建了水网布局下黄河流域应对极端枯水的总体研究框架,提出该领域重点研究方向包括:变化环境下长江、黄河极端枯水遭遇规律与空间变异机制,水危机风险多链路传导与复合影响定量评估,极端枯水下跨流域调水挖潜增供,长江和黄河跨流域联合调配与多线路互济精细化调控、极端枯水下流域水资源韧性提升优化调控等。