Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu Lake in Taihu Basin

On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtz,e River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and water quality conjunctive dispatching ＇decisi＂ofi-makifig support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the -integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

Super-long Qinling Tunnel for Han River to Wei River Water Diversion Project

Han River to Wei River Water Diversion Project in Shaanxi Province is an inter-basin water diversion project approved by the State Council in 2005,which is a key hydraulic project in the 12th Five-Year Plan of China.It is expected to solve water resources shortage in the Guanzhong area of Shaanxi Province,effectively curb the deterioration of ecological environment in Wei River and reduce environmental geological disasters in the Guanzhong area.It is a strategic project for optimal allocation of water resources by adjusting the distribution of water resources in Shaanxi Province and promoting the economic development of the Guanzhong-Tianshui Economic Zone.Implementation of the project is of great importance to the sustainable economic and social development of the Guanzhong area.The project crosses the Yangtze River and Yellow River basins and passes through the Qinling Mountain.The huge-scale project has a profound historic impact on the economic development in the region.

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.

Relationship between Macroinvertebrates and Physico-Chemical Parameters to Access Water Quality of the Affon River in Bénin

The Affon River is one of the important rivers of the Ouémé River whose benthic diversity remained unknown. The present study aims to make the relationship between macroinvertebrates and physico-chemical parameters to access water quality of the Affon River. The measurement of physico-chemical parameters (temperature, pH, conductivity, transparency, depth and TDS, dissolved oxygen, ammonium, nitrite and phosphate) and the sampling of macroinvertebrates using a Surber net were carried out during floods in eight stations. A principal component analysis (PCA) and canonical correspondence analysis (CCA) were used. The indices of Shannon, Piélou, Simpson, Hilsenhoff, EPT and EPT/Chironomidae were used to assess the level of water pollution. The study identified 9755 macroinvertebrates divided into 4 classes, 14 orders and 49 families. Pollution-sensitive families (14 families) that are organic pollution indicators, as well as pollution-tolerant families (Chironomidae, Limnaeidae, Bithynidae, Physidae) were captured. Chironomidae were the most predominant and abundant family (FO = 100%). The predominance of Chironomidae coupled with the rarity of the Ephemeroptera, Trichoptera and Plecoptera would reflect the poor quality of the Affon River waters. The principal components analysis yielded groups of associations: The first group of stations Taneka 2 and 3 characterized by high values of ammonium and phosphate;and low values of conductivity and TDS;the second group of Tanéka 1 and Kolokondé 1 stations with low values of pH, transparency, ammonium and phosphates;and the third group of stations Kolokondé 2, Kpébouko1, Kpébouko 2 and Affon marked by high values of conductivity, TDS, transparency, depth and temperature. The canonical correspondence analysis revealed a strong positive correlation between Nemouridae and ammonium as well as between Perlidae, Taeniopterygidae, Ephemeridae, Heptageniidae, Isonychiidae, Elmidae and phosphate. This study is a crucial step for any management and monitoring of this river.

Real-time flood forecasting of Huai River with flood diversion and retarding areas

A combination of the rainfall-runoff module of the Xin’anjiang model, the Muskingum routing method, the water stage simulating hydrologic method, the diffusion wave nonlinear water stage method, and the real-time error correction method is applied to the real-time flood forecasting and regulation of the Huai River with flood diversion and retarding areas. The Xin’anjiang model is used to forecast the flood discharge hydrograph of the upstream and tributary. The flood routing of the main channel and flood diversion areas is based on the Muskingum method. The water stage of the downstream boundary condition is calculated with the water stage simulating hydrologic method and the water stages of each cross section are calculated from downstream to upstream with the diffusion wave nonlinear water stage method. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The faded-memory forgetting factor least square of error series is used as the real-time error correction method for forecasting discharge and water stage. As an example, the combined models were applied to flood forecasting and regulation of the upper reaches of the Huai River above Lutaizi during the 2007 flood season. The forecast achieves a high accuracy and the results show that the combined models provide a scientific way of flood forecasting and regulation for a complex watershed with flood diversion and retarding areas.

Wet-Dry Runoff Correlation in Western Route of South-to-North Water Diversion Project,China

The Western Route of the South-to-North Water Diversion Project is an important trans-basin diversion project to transfer water from the upstream Yangtze River and its tributaries （water-exporting area）, to the upstream of the Yellow River （water- importing area）. The long-term hydrologieal data from 14 stream gauging stations in the Western Route area and techniques including the pre-whitening approach, non-parametric test, Bayes, law, variance analysis extrapolation, and Wavelet Analysis are applied to identify the streamflow eharacteristics and trends, streamflow time series cross-correlations, wetness-dryness encountering probability, and periodicities that occurred over the last 50 years. The results show that the water-exporting area, water- importing area, and the streteh downstream of the water-exporting have synehronization in high-low flow relationship, whereas they display non- synchronization in long-term evolution. This corresponds to the complicated and variable climate of the plateau region. There is no obvious increasing or decreasing trend in runoff at any gauging station. The best hydrological eompensation probability for rivers where water is diverted is about 25% to lO%, and those rivers influenced significantly by diversion are the Jinsha and Yalong rivers. Proper planning and design of compensation reservoirs for the water-exporting area and stretch downstream of the water- exporting area can increase the hydrological compensation possibility from water-exporting area to the water-importing area, and reduce the impact on the stretch of river downstream of the water- exporting area.

Application of River Network Hydrodynamic Model in Determining Water Distribution Scale of Haishu Plain

The water distribution network is an important part of the plain water environment improvement system. To make efficient use of the regional water diversion source, scientifically distribute the water diversion flow and improve the water environment carrying capacity of Haishu Plain, the river network hydrodynamic model is used in this paper to simulate the water intake location, reasonable water quantity and influence range of water transfer in Haishu Plain. The simulation results have high accuracy, which can provide a scientific basis for the scale, water transfer mechanism and project layout of water transfer construction in Haishu Plain and show a strong reference value for the study of water diversion and distribution scheme of coastal plain river network.

A numerical study on water diversion ratio of the Changjiang(Yangtze)estuary in dry season

We studied the flood, ebb and tidal averaged along (net) water diversion ratio (WDR) during dry season in the Changjiang (Yangtze) estuary, China, along with the effects of northerly wind, river discharge, tide and their interactions on WDR using the improved version of three-dimensional numerical model ECOM. Using data for annual mean wind speed and river discharge during January, we determined that the flood, ebb, net WDR values in the North Branch of the estuary were 3.48%, 1.68%,-4.06% during spring tide, and 4.82%, 2.34%,-2.79% during neap tide, respectively. Negative net WDR values denote the transport of water from the North Branch into the South Branch. Using the same data, the corresponding ratios were 50.09%, 50.92%, 54.97%, and 52.33%, 50.15%, 43.86% in the North Channel and 38.56%, 44.78%, 103.96%, and 36.92%, 43.17%, 60.97% in the North Passage, respectively. When northerly wind speed increased, landward Ekman transport was enhanced in the North Branch, increasing the flood WDR, while the ebb WDR declined and the net WDR exhibited a significant decrease. Similarly, in the North Channel, the flood WDR is increased, the ebb WDR reduced, and the net WDR showed a marked decrease. In the North Passage, the flood WDR also increased while the ebb and net WDR declined. As the river discharge increased, the flood and ebb WDR of the North Branch increased slightly and the net WDR increased markedly. In the North Channel the flood and ebb WDR changed very slightly, while the net WDR declined during spring tides and increased during neap tides. The WDR in the North Passage changed slightly during flood and ebb tides while the net WDR showed a marked increase. The WDR values of different bifurcations and the responses to northerly wind, river discharge, and tide are discussed in comparison with variations in river topography, horizontal wind-induced circulation, and tidal-induced residual current.

Engineering Strategies on Flood Control in Middle Reach of Yangtze River, China

Flood disaster has been a serious hidden danger since the ancient time. The essential cause for the fact that floods have not been eliminated for hundreds of years is that time honored strategies do not suit the cases of flood prevention. In the view of geological environmental analyses of flood formation and from the synthesis of experiences gained in flood control in the past hundreds of years, sluggish draining of flood, silt sedimentation in channel and building levee blindly constitute the main cause of intractable flood for a long time in the middle reach of the Yangtze River. Draining away silt and water is the only way to stamping out flood disaster. Opening up artificial waterways for flood diversion, draining away the silt of channel into the polders, and storing the flood water are important engineering measures for the flood control and damage reduction.

Increasing probability of concurrent drought between the water intake and receiving regions of the Hanjiang to Weihe River Water Diversion Project,China

Water diversion projects are an effective measure to mitigate water shortages in water-limited areas.Understanding the risk of such projects increasing concurrent drought between the water intake and receiving regions is essential for sustainable water management.This study calculates concurrent drought probability between the water intake and receiving regions of the Hanjiang to Weihe River Water Diversion Project using Standardized Precipitation Index and Copula functions.Results showed an increasing trend in drought probability across both the water intake and receiving regions from 2.67%and 8.38%to 12.47%and 14.18%,respectively,during 1969-2018.The return period of concurrent drought decreased from 111.11 to 13.05 years,indicating larger risk of simultaneous drought between the two regions.Projections from CMIP6 suggested that under the SSP 2-4.5 and 5-8.5 scenarios,concurrent drought probability would increase by 2.40%and 7.72%in 2019-2050 compared to that in 1969-1990,respectively.Although increases in precipitation during 2019-2050 could potentially alleviate drought conditions relative to those during 1991-2018,high precipitation variability adds to the uncertainty about future concurrent drought.These findings provide a basis for better understanding concurrent drought and its impact on water diversion projects in a changing climate,and facilitate the establishment of adaptation countermeasures to ensure sustainable water availability.

基于组合权重TOPSIS模型的河南省引黄受水区水资源承载力研究

为确定河南省引黄受水区水资源承载力状况,构建了包括水资源、生态环境和经济社会3个准则的指标体系,采用基于AHP法和EWM法组合权重的TOPSIS模型,对该区2010-2021年水资源承载力进行评价。结果表明:2010-2021年河南省引黄受水区水资源承载力呈现上升态势,但水资源承载力等级整体偏低,大多数为Ⅲ级(临界),均未达到Ⅰ级(可承载)水平;2021年河南省引黄受水区水资源承载力障碍因子中供水模数影响最大,城市污水处理率影响最小;从水资源和生态环境准则来看,该地区水资源承载力还有很大提升空间,可以从加大水资源管理力度、加强节水宣传等方面加以改善。

Why Does the Repaired Len Small Levee, Alexander County, Illinois, US Continue to Breach during Major Flooding Events?

One only needs to study the soil and geologic history and location of the ancient Mississippi and Ohio Rivers to understand why Len Small levee if patched will continue to fail. Much of Dogtooth Bend located in Alexander County, Illinois was originally in the ancient Ohio River valley (Figure 1) alluvial sediments north and east of the confluence with the ancient Mississippi River. The ancient Ohio River valley soils underlain by alluvial sediments and have been easily eroded by the re-aligning modern Mississippi River which now travels through the bedrock controlled Thebes Gap (Figure 2) and into the Ancient Ohio river valley. The primary objectives of this paper are: 1) to explain why Len Small levee, Alexander County, Illinois, US will continue to breach during major flooding events if repaired and 2) to develop a new combined raised causeway and levee system which will provide a Mississippi River floodwater bypass, be sustainable, encourage and fund a land use change, restore the degraded highway road beds, protect remaining Dogtooth Bend farmsteads and farmland that have not yet been degraded by past flooding events and provide floodwater storage during major flooding events at the confluence of the Mississippi and Ohio Rivers.

A STUDY ON THE WATER RESOURCES AND SEDIMENT PROBLEMS IN THE IRRIGATED AREA OF NORTHWEST SHANDONG PROVINCE

There are very serious water and sediment problems in the irrigated areas of northwest Shandong Province. In upper reaches of the irrigated area, the Yellow River water are widely used for farmland watering while leaving the ground water unusedion. But in the lower reaches, there is not enough surface water to be channeled for irrigation, so the ground water has always been over extracted, in some parts of the lower reaches, the descending water table caused the formation of funnel. Siltation in canals are very difficult to be cleared up, the drop of agriculture yield in the sandy land close to the channel head and along the main channels impair the living conditions of the local people. The conflicts between the excessive dependence on the Yellow River and the decreasing tendancy of water amount provided by the Yellow Ricer forces the local government to find new ways to solve the water resource problems. The answer could be: Using new technique for the irrigated system, pay more attention to the ground water development, and the construction and maintenance of wells.

平原河网水动力优化调度与水环境改善的响应关系研究

平原河网河道流动性较差是引起水环境污染严重的主要原因,引调水是改善平原河网地区水环境的重要措施之一。本文以佛山市三山围为例,基于实测资料构建了河网水动力水质耦合模型,采用15天的连续水动力水质监测数据对模型进行了验证,并将NSE和RMSE模型评价指标用于模型评价。同时结合地势、潮汐规律和景观水位等设计了4种闸控模式和7种景观控制水位,共28种模拟工况,模拟分析了不同条件下的水动力水质改善与内外江潮位变化、引排水流量及其空间分布、闸控方式和景观水位等综合响应机理。结果表明:构建的模型合理可靠。研究区域受引排水路径的影响,河道流动性差异较为显著。综合考虑河道流量分布、水流路径、分汊河道分流作用和外江污染物浓度等对河道水质的作用效果并有效结合潮汐河网的动态水环境容量和污染源排放的时空分布对水环境的改善作用将非常显著。与低景观控制水位相比,高景观控制水位的内江动态水环境容量相对较大,污染物浓度较低。景观控制水位从0.2 m上升至0.8 m时,不同引调水路径的引水流量上升28.00%~64.70%,断面氨氮浓度削减了0.85~5.50 mg/L,削减比例达到28.89%~67.23%。本研究为平原潮汐河网水环境优化调度研究提供了新的思路,为相关部门对平原河网的水环境改善提供了重要的参考。

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。

引江济淮工程(河南段)水资源调配系统设计与开发

为强化引江济淮工程(河南段)水资源统一调配,基于Spring Boot和Vue前后端分离开发的模式,利用天地图API、WebGL、Echarts等技术设计研发引江济淮工程(河南段)水资源调配系统。从设计思路、功能界面、关键技术3个角度论述系统设计思路和实现过程,从而实现地理信息服务、供需水预测、水资源优化配置、水资源优化调度等功能,实现水量分配可视化、运行调度智能化和跨流域调水管控一体化。系统测试结果表明:引江济淮工程(河南段)水资源调配系统的建立提高了受水区水资源精细化管理的水平,解决了引江济淮工程(河南段)跨流域调水的配置难题,为受水区水资源高效利用提供有效的技术支撑。

引江补汉工程丹江口下游近坝段枯水期通航水位恢复试验研究

引江补汉工程补水口位于丹江口大坝下游安乐河出口约5 km处,且补水量与调水量基本一致,工程对航道的影响主要体现在减水段,为恢复枯水期通航水位需要开展航道综合治理。利用河工模型试验论证了综合治理方案的效果,并对方案进行了优化及进一步论证。结果表明,减水-补水212 m 3/s方案尾门水位分别为86.47、85.90 m条件下,引航道口—黄家港段水位下降,黄家港以下水位保持不变,其中引航道口水位下降幅度最大,分别下降0.08、0.19 m;综合治理方案1实施后引航道口水位下降均为0.02 m,减水段的水位仍未恢复至调水前的水平,主因是从安乐河口补水的水流并未能进入到左侧主航道内;基于试验研究结果,建议对综合治理方案进行优化,在沧浪洲出水口下沿布置2道护底带;通过试验论证了护底带的4个高程,建议护底带高程为85.5 m,并对护底带高程进一步细化论证;优化后的方案可使引航道口至黄家港段的水位略超过调水前的水平,其中引航道口处最大水位抬高0.06 m。

不同调水方式对巢湖水质影响模拟

引调水工程是目前用来改善湖泊水质的重要手段,然而引调水的调水路线、来水水量以及来水水质对湖泊水质改善效果都至关重要。本文以“引江济巢”工程为例,针对巢湖的浅水湖泊特征,考虑引调水入湖后不仅对水量和水质有直接改善作用,还可能因为湖区水动力条件改变及内源释放影响水质,通过构建二维水动力水质模型,模拟不同调水路线、水量下湖区水动力条件,进一步考虑不同来水水质和底泥释放对水质改善的影响。结果显示,调水对流场的扰动在丰水年较弱、枯水年较强,流量对湖区水质影响随流量增大而增强,来水水质的优劣是决定湖区水体水质是否改善的关键。整体而言,西湖区受调水影响较小,东湖区能够对全湖水质变化起到指示作用。调水方案应基于湖泊实际水量与水质状态综合考虑调水流量与水质制定。

基于时序Sentinel-2影像的引黄灌区作物结构提取和供需水分析

在黄河流域用水指标严格控制的背景下,以山东省东营市垦利区引黄灌区为例,利用2022年时序Sentinel-2遥感影像构建作物生育期的NDVI时间序列,采用决策树分类方法提取灌区作物种植结构,基于垦利站气象资料和Penman-Monteith公式,分析了1973—2022年各作物的需水特性,利用遥感影像解译的各作物种植面积,计算了2022年灌区作物在不同降水保证率(5%、25%、50%、75%、95%)条件下的灌溉总需水量,结合2023年分配给灌区作物的灌溉水指标探究了灌溉水资源供需之间的平衡。结果表明:基于NDVI时间序列构建决策树分类方法可有效提取作物的种植结构,总体分类精度为85.07%,Kappa系数为0.819,能够满足作物灌溉需水量的研究。作物净灌溉需水量年际波动较大,水稻和冬小麦补充灌溉水量在所有作物中位列前两位,均值分别为913 mm和410 mm;处于雨季生长的夏玉米、夏大豆补充灌溉水量较小且灌溉需求均值较小。研究区2023年分配的灌溉水指标在降水保证率为50%时研究区灌溉水亏缺量为235.5万m^(3),在降水保证率为75%和95%时灌溉水亏缺量分别为1 754.5万m^(3)和2 261.5万m^(3)。