Projecting Spring Consecutive Rainfall Events in the Three Gorges Reservoir Based on Triple-Nested Dynamical Downscaling

Spring consecutive rainfall events(CREs) are key triggers of geological hazards in the Three Gorges Reservoir area(TGR), China. However, previous projections of CREs based on the direct outputs of global climate models(GCMs) are subject to considerable uncertainties, largely caused by their coarse resolution. This study applies a triple-nested WRF(Weather Research and Forecasting) model dynamical downscaling, driven by a GCM, MIROC6(Model for Interdisciplinary Research on Climate, version 6), to improve the historical simulation and reduce the uncertainties in the future projection of CREs in the TGR. Results indicate that WRF has better performances in reproducing the observed rainfall in terms of the daily probability distribution, monthly evolution and duration of rainfall events, demonstrating the ability of WRF in simulating CREs. Thus, the triple-nested WRF is applied to project the future changes of CREs under the middle-of-the-road and fossil-fueled development scenarios. It is indicated that light and moderate rainfall and the duration of continuous rainfall spells will decrease in the TGR, leading to a decrease in the frequency of CREs. Meanwhile, the duration, rainfall amount, and intensity of CREs is projected to regional increase in the central-west TGR. These results are inconsistent with the raw projection of MIROC6. Observational diagnosis implies that CREs are mainly contributed by the vertical moisture advection. Such a synoptic contribution is captured well by WRF, which is not the case in MIROC6,indicating larger uncertainties in the CREs projected by MIROC6.

Estimation of Potential Risk of Reservoir-Induced Earthquake for the Proposed Hydroelectric Project on the Yangtze Gorges

The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the world.A research program has been carried out by the State Seismological Bureau of China.Based on the size of the reservoir and the lithology,geological structure,permeability,stress state,and previous seismicity in the region,the potential risk of reservoir-induced seismicity has been estimated.The results suggest that,after impoundment in the reservoir area,the possibility of induced seismicity cannot be completely ruled out.The areas with potential risk may be in some gorges composed of karstified carbonate and plutonic granite around the dam site.However,the magnitude is expected to be limited owing to the small dimension of the induced seismogenic faults.

Impact on Mountainous Agricultural Development in the Three Gorges Reservoir Area forced by Migrants of the Three Gorges Project

The Three Gorges Project attracts worldwide attention because of the Three Gorges migrants, and the agriculture of the Three Gorges Reservoir Area is a foundation for the development of the Three Gorges migrants. The Three Gorges Reservoir Area is situated at the mountainous area with bad agricultural development conditions and relatively low levels of development. As a result, the large-scale migration fias special influence on its agricultural development, which has attracted much attention. The paper analyzes influence that the migrants have forced on its agricultural development based on the scientific data, and makes some explorations on the models that are suitable for the development of mountainous agriculture in the Three Gorges Reservoir Area.

Soil Geochemistry Changes Induced by a Foreign Soil Reconstruction Project in Three Gorges Reservoir Region of China

Fertile topsoil was added onto the surface of barren slope land in Three Gorges Reservoir region of China in an anthropogenic process known as the foreign soil reconstruction project. The main goal of this paper was to reveal the influence of anthropogenic activities on pedogenic processes and soil classifications. Chemical weathering indices and comparative analysis were applied to discuss changes in geochemical compositions and weathering features of purplish soils(Cambisols) before and after the project. Results showed that:(1) The foreign soil reconstruction project slightly altered the major element composition of topsoil and improved the soil structure. Although the distributions of major elements in the original topsoil, original subsoil, foreign topsoil and newly constructed topsoil were all similar to that in upper continental crust, newly constructed topsoil was the most similar soil.(2) The chemical index of alteration was more sensitive than the weathering index of Parker at indicating chemical weathering status of purplish soil. The chemical weathering status of newly constructed topsoil was higher than that of the original topsoil and lower than that of foreign topsoil.(3) Anthropogenic activities may provide a promising new thought for the anthropogenic soil classification system. The scope and subgroups of Anthrosols should be extended and strengthened. Or there may be a need to combine Anthrosols and Technosols orders to create a new soil order. The results may be used for optimizing soil mellowing engineering activities and enriching the soil classification system.

Seismic hazard assessment of the Three Gorges Project

Seismic monitoring data for the past 50 years in the Three Gorges Reservoir area show that the reservoir head area is a typical weak seismic region with low seismieity before impoundment and that the epicenters were concentrated in the east and west sides of the Zigui Basin, most of which were natural tectonic earth- quakes. After impoundment, the seismic activity shifted to the segment between Badong and Zigui along the Yangtze River, mainly within 5 km of the reservoir bank. The seismogenesis was categorized into four types： Karst collapse earthquakes, earthquakes caused by Karst gas explosion, mining tunnel collapse earthquakes, and rock （terrane） slip earthquakes, all of which are related to the lithology, structure, and tectonics of near- surface geological bodies of the area. Compared with the seismicity before impoundment, the seismic frequency increase was remarkable, with most of the magnitudes below Ms2.0. Therefore, the intensity of the earth- quakes remained at a low level. On November 22, 2008, a magnitude 4.1 earthquake, the largest earthquake recorded since impoundment, occurred in Quyuan Town, Zigui County. The intensity and PGA of reservoir-in- duced earthquakes are higher than those of tectonic earthquakes with equal magnitude, but the peak intensity of reservoir-induced earthquakes is not likely to go beyond that of the estimated range from earlier studies.

A Comparative Overview of Three Gorges Project's Sediment Handling

Water projects’ sediment deposition problems always cause widespread concerns. The gravity of them varies in accordance not only with reservoirs’ natural and socio-economic characteristics but also with their modes of operation. The unique characteristics, configuration and mode of operation of Three Gorges Project (TGP) reservoir are compared with those of several existing large reservoirs in this paper. As many reservoirs are troubling environment by gradually extending coarse sediment deposition at the uppermost end of fluctuating backwater region toward upstream, Gezhouba reservoir on Yangtze and Danjiangkou reservoir on Hanjiang have shown no trace of such upstream extension of sediment deposition in relevant prototype observation data for the past 20 and more years. TGP reservoir’s in-coming flow sediment conditions and configuration in plane are almost the same as those of Gezhouba reservoir, and TGP reservoir’s mode of operation(usually keeping a very low pool level for flood control in flood season and storing up in-coming flow only thenceafter) is similar to that of Danjiangkou reservoir. New findings of sediment research and prototype flow sediment investigations as well as new agenda of large hydro projects’ construction on Jinshajiang in nearest future assure the prospects of TGP sediment handling.

The resettlement planning and practice of Three Gorges Project

Migrant resettlement is essential to the success of the Three Gorges Project (TGP),and the smooth implementation of resettlement is ensured by the resettlement planning and effective organization management.In the process of resettlement planning and implementation,systematic legislation and document support system is established;environmental capacity analysis and assets appraisal methods are introduced;resettlement sites are selected through in-depth analysis and comparison;the relationship between resettlement compensation and local development is correctly understood and considered,and reasonable resettlement schedules are well prepared.Through the establishment of efficient management system and capital management mode of "static control and dynamic management",as well as the timely adjustment of plan according to actual situations,the resettlement is accomplished smoothly.Thus,the social stability of the reservoir area is ensured;the economic development of reservoir area is promoted,and it has promoted successfully the improvement of legislation,regulations and techniques for land requisition and resettlement.The paper also discusses the theory and prospective work of resettlement.

冲刷及整治工程叠加作用下武汉河段滩槽调整特征与成因

大型水库的修建引起了坝下游的滩槽调整,进而对河势、航运、防洪及生态等产生显著影响。为探究滩槽调整的驱动机制,采用1952—2022年水沙和1959—2021年地形观测资料,以长江武汉河段为例,分析了床沙组成、来水来沙及整治工程等因素的影响。研究表明:①武汉河段枯水河槽冲刷量占全河槽冲刷量的90.4%,断面趋向窄深化,河相系数减小。不同江心洲及汊道冲淤出现差异性调整,2001—2021年,铁板洲和白沙洲洲体面积分别减少了63.1%和61.5%,潜洲和天兴洲洲体面积分别增大了212.3%和14.5%;2013年后,铁板洲左右汊均冲,天兴洲汊道左淤右冲。②来沙量锐减,河床以0.125 mm≤d<0.25 mm的细沙居多,抗冲性较弱,是冲刷加剧的先决条件;三峡水库的削峰补枯作用加剧了枯水倾向汊河的冲刷幅度;整治工程改变了滩槽冲淤的横向分布,是江心洲差异性调整的主导因素,也是天兴洲保持左淤右冲的重要原因。③三峡水库蓄水前,洲滩之间演变联动性强;三峡水库蓄水后,来沙减少和中水期时间延长导致洲滩冲刷萎缩,洲滩之间演变联动性变弱;整治工程实施后,工程保持了心滩稳定且其缓流滞沙效应提高了抗冲性,心滩淤长的同时限制了边滩发育,叠加来沙进一步减少,边滩之间、心滩之间演变联动性进一步变弱,边滩与心滩之间演变联动性再次增强。

引江补汉工程控制枢纽品字型双层闸门水力控制技术

石花控制闸是引江补汉工程的控制枢纽,采用品字型双层闸门布置解决了引江补汉工程高水头、超长有压输水水力控制关键技术难题。为了探究石花控制闸品字型双层闸门水力控制技术,采用数值计算和水工模型试验的方法开展研究:①采用一维、三维耦合数学模型计算控制闸启闭引起的系统水力过渡过程,为工程设计提供边界条件;②采用物理模型试验分析控制闸体型的合理性。结果表明:系统沿线最大、最小压力均满足相关规程要求;控制闸内水流流态、压力分布等指标正常,控制闸体型合理。石花控制闸总体设计方案合理,布置方式和研究方法可为其他类似工程提供参考。

农村供水工程中生物慢滤净水工艺数字孪生实践

在新形势下,国家大力推进数字孪生技术在农村供水工程管理中的应用。我国西南丘陵山区农民居住较为分散,水源多样,生物慢滤技术因其构造简单、对水质适应性强而被广泛应用,但在日常运行过程中存在维护不及时、无法准确判断出水是否达标等问题,对供水安全构成威胁。生物慢滤技术实施数字孪生建设,通过在关键节点安装监控设备,监测供水过程的浊度、滤速和水质等参数,监测数据由无线遥感终端汇集至数据分析系统,对超出阈值的实时数据发出报警,通知管水员实地检查。三峡库区秭归县水田坝乡工程实践结果表明,农村供水工程进行智慧化改造能够改变人工现地管理传统方式,减轻了管水员的工作压力,供水水质得到保障。从实践的效果来看,生物慢滤净水工艺数字孪生是农村供水工程智慧化供水的一次有益尝试。

基于卫星遥感的涉河建设项目调查平台设计与应用

涉河建设项目建设周期长,存在数据更新滞后和共享不方便的问题,为了及时掌握涉河建设项目的建设现状,利用卫星遥感影像、地理信息技术和计算机技术,探索了内业外业在线协同工作的模式,按照数据收集、内业解译研判、外业复核、成果整理的建设思路,研发了涉河建设项目在线调查平台,并在三峡库区涉河建设项目调查中得到应用,最终形成了一套包括1425个涉河建设项目的台账数据。结果表明:该平台实现了涉河建设项目的内业解译研判和外业采集复核等功能,提高了数据更新效率,提供了数据共享渠道。研究成果对三峡库区范围内的涉河项目管理及摸清河湖岸线利用现状具有借鉴意义。

三峡工程泥沙问题研究进展与展望

泥沙问题是三峡工程的关键技术问题之一,关系到三峡工程设计成败和安全高效运行。在三峡工程论证、设计、建设和运行的各个阶段,针对重大的工程泥沙问题进行了系统和持续的监测与研究,为三峡工程成功建成与运行提供了重要科技支撑。本文系统阐述了三峡工程泥沙问题的研究历程与解决途径,对三峡水库蓄水运用以来入库水沙变化、水库淤积、坝下游冲刷、泥沙优化调度等方面取得的研究成果进行了分析总结。研究成果表明三峡工程泥沙问题及其影响基本未超出论证与初步设计的预测,处于安全可控状态。本文还根据新需求对今后泥沙问题研究提出了建议,包括梯级水库泥沙联合调度、泥沙变化的生态效益、泥沙监测技术提升等。

发挥长江经济带关键骨干作用 促进三峡工程安全运行和库区高质量发展

三峡工程是“国之重器”,具有防洪、发电、航运、水资源利用等巨大的综合效益,是长江的骨干性、控制性水利枢纽工程,在长江大保护与长江经济带高质量发展中发挥了巨大的作用。按照习近平总书记关于三峡工程“一个标志、三个典范”的高度评价,文章准确把握了三峡工程和三峡库区在长江经济带发展中的关键骨干作用,深入理解了三峡工程安全运行和库区高质量发展面临的新形势新要求,合理确定了世界水工程安全运行管理典范、国家重要淡水资源战略储备库、生态优先绿色发展和谐稳定共同富裕示范区、人与自然和谐共生三峡新文化引领者等四大战略定位,系统谋划了促进三峡工程高水平安全运行和库区高质量发展的具体实施路径。

引江补汉工程部分岩石磨耗性与等效石英含量关系

为研究引江补汉工程岩石磨耗性与岩石矿物组成之间的关系,通过收集整理工程地质勘察过程中获得的部分岩石磨耗性指数(CAI)及其相应矿物成分测试数据,进行岩石等效石英含量Qe及其与岩石磨耗性CAI值的相关性分析计算。结果表明:在收集的数据中,侵入岩和片麻岩岩石磨耗性和等效石英含量相对较高,对TBM刀具磨损影响较大,碳酸盐岩相对较低;侵入岩和片麻岩的岩石磨耗性CAI值具有随等效石英含量Qe的增加而增大的趋势,两者之间具有相关关系,碳酸盐岩岩石CAI值与Qe无统计上的相关关系;部分碳酸盐等效石英含量较低,但具有较高的磨耗性,据此可推测岩石矿物成分不是控制其磨耗性的主要因素。

The analysis on reservoir sediment deposition and downstream river channel scouring after impoundment and operation of TGP

According to the measured data after impoundment and operation of the Three Gorges Reservoir,the reservoir sediment deposition and downstream river channel scouring are described briefly and compared with the research results achieved in the demonstration stage.It is indicated through analysis that the reservoir sediment deposition and downstream river channel scouring during 8-year impoundment and operation are still within the original forecast,so the original forecasting results are feasible.The further observation and comparison should be conducted because the comparison between the observed data and the original forecast is not so sufficient in time and the prototype observation and related research work should be strengthened in the future.

三峡工程运行后水库下游弯曲河道演变规律

三峡工程运行后水库下游河道水沙过程发生较大改变,引起弯曲型河道演变规律调整,对河势稳定、防洪安全等可能产生不利影响。基于实测资料分析了三峡工程运行后水库河道下游典型弯道演变规律及其主要动因。结果表明,三峡工程运行后水库下游典型弯道段均出现“切滩”,其主要原因是进入各河段的泥沙尤其是细颗粒沙量大幅减少;而下荆江绝大多数弯道段出现“撇弯”的主要原因为月均径流量过程变异系数较大、弯道段本身弯曲半径较小。随着长江上游干支流梯级水库陆续运行,预计水库下游各河段月均径流量过程变异系数将继续增大,将可能引起目前未发生“撇弯”但弯曲半径相对较小的弯道段发生“撇弯”。

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。

数字孪生三峡建设总体框架及应用效益

数字孪生三峡建设可推进实体工程与数字孪生工程同步交互映像,有效提升长江流域调度管理以及三峡工程综合管理能力,确保三峡工程长期安全稳定运行,更好地发挥综合效益。分析了数字孪生三峡建设的目标,对由信息化基础设施、数字孪生平台、业务应用、网络安全体系、保障体系组成的数字孪生三峡建设总体框架进行了介绍,从防洪精准调度、三峡枢纽工程运行安全管理、三峡水库运行安全管理等方面总结了数字孪生三峡建设的初步成果及应用效益,并对下一步建设提出了建议。

强干扰河流生态学基本问题与技术体系探析

河流生态系统在强干扰行为影响下将发生系列变化。归纳了国内外对河流生态学的研究进展,论述了强干扰河流的定义、分类、生态学特征,从水文、地貌、泥沙、生物四个方面建立强干扰河流生态学研究框架,并构建了包括水库生态系统、水工程生态调度、过鱼设施、水生生物保护区、鱼类洄游特性五个方面的技术体系,对其应用场景进行了分析。

引江补汉工程输水线路工程地质选线研究

引江补汉工程是南水北调中线工程的后续工程,可行性研究阶段坝下方案输水隧洞初拟4条线路进行比选,比选线路区地形地质条件和工程地质问题复杂,具有线路长、埋深大,地层岩性复杂多样、可溶岩和软质岩分布较多,地质构造背景复杂、总体地应力水平高等地质特点,深埋长隧洞工程可能涉及的工程地质问题均有可能出现,有必要选择一条地质条件相对较优的线路。经分析研究,将线路比选考虑的地质因素分为关键地质因素、重要地质因素、一般地质因素,并建立多因子条件下的线路比选模型,经工程地质综合比选,龙安1线输水隧洞方案总体较优,地质选线成果为工程设计综合选线提供了重要依据,地质比选研究思路与方法可为同类工程提供借鉴。