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There are great distances between the embankments from Baihezhen to Taochengpu in the Yellow River where historically erosion and deposition of the channel had been changed rapidly and the river is in the wandering and varying regime. After years of improvement, the river regime has been basically controlled on the whole and the channel has gradually become stabilized. Under these conditions, in order to promote the ecological protection of the Yellow River and the development of floodplain areas, upgrade the level of river management, the river was simply divided into channel and floodplain. This paper proposed the concept of channel alignment for the first time, provided the definition and the principle of alignment setting, emphasized that establishing the channel alignment should take the safety of flood control as the premise, explained setting methods and on-site marking methods and also analyzed the functions of channel alignment. [ABSTRACT FROM AUTHOR]

Xiaolangdi Reservoir has played a great role in flood control, sediment reduction and profit improvement. This paper systematically analyzed the flood control operation and the function of the Xiaolangdi Reservoir. By analyzing the sediment erosion and sedimentation of the reservoir and the Lower Yellow River, the effect of sediment reduction of the reservoir was proposed. The benefit of flood control and sediment reduction of the reservoir was calculated. The results show that the reservoirs in the middle reaches of the Yellow River can block the flood and cut the peak for 15 times. The average peak cutting rate of Huayuankou Station is 36%, and the maximum peak cutting flow is 7 560 m³/s, which can effectively avoid the flood losses in the downstream beach area. Due to the decrease of sediment load, the sedimentation rate of the reservoir is lower than that in the design stage, and the sediment retention ratio of 1.26 relative to the downstream channel is lower than that of 1.57 in the design sediment retention stage. The sediment reduction effect of the reservoir is better, especially in the reach below the Aishan. According to the 2020 price level, the actual annual benefits of flood control (ice-run prevention) and sediment reduction of the reservoir are 5.927 billion Yuan more than the design value, and the cumulative present value of benefits is 21.873 billion Yuan more than the total investment (including power generation), indicating the economic rationality of the construction of the Yellow River water and sediment regulation backbone project, which provides a successful example for accelerating the construction of Guxian project [ABSTRACT FROM AUTHOR]

Fully tapping the regulating potential of reservoir groups in the middle reaches of the Yellow River and improving the sediment transport capacity of the lower reaches of the Yellow River play an important guiding role on river and beach management in the lower reaches of the Yellow River. Through the analysis of measured data and mathematical models, this paper calculated the influence of combined regulation and control of existing reservoir groups under different water and sediment conditions on sediment transport capacity of the lower reaches of the Yellow River, and further to analyzed the change of sediment transport capacity of the lower reaches of the Yellow River after Guxian and Dongzhuang reservoirs come into effect. The results indicate that by optimizing the joint regulation and control mode of the existing reservoir groups, the flow process with large sediment concentration discharged by the reservoir can increase the sediment carrying capacity of the downstream river by about 10%-12%. The sediment discharge into the downstream river during the sediment retaining period after Guxian and Dongzhuang Reservoirs come into effect are reduced, and the sediment transport capacity can be further improved by 11%-12% during the normal operation period. [ABSTRACT FROM AUTHOR]

Exploring the beach land function change and its driving factors in the lower reaches of the Yellow River is one of the important ways to promote the optimization and sustainable development of land function in the study area. Based on the land use remote sensing data from 1980 to 2020, this paper analyzed the temporal and spatial variation characteristics of various types of land functional land in the study area, and used geographical detectors to study the influence intensity and interaction mechanism of various factors on the land function change of the river beach and water area in the lower reaches of the Yellow River. The results show that a) the economic and water-sediment functional land covers the largest area and has the widest distribution range. The former is distributed along the river channel, and the area shows a trend of “sharp decrease-slow increase-stable”; the latter is along the river channel. b) Soil type and population spatial distribution are important driving factors affecting land function change in the study area. The spatial-temporal differentiation exhibits two-factor enhancement and nonlinear enhancement. [ABSTRACT FROM AUTHOR]

Continuous sharp bends exist widely in natural rivers. Studying the law of water and sediment movement has important guiding significance for the regulation and disaster prevention of sharp bends. Based on the movable bed physical model test of unsteady flow bed, this paper discussed the cumulative effect of continuous sharp bends on sediment transport capacity of the lower Yellow River reach. The results show that the continuous sharp bends cause additional energy loss, which leads to the overall deposition of the river channel under specific water and sediment conditions. The sediment transport capacity of the continuous sharp bend sections declines along the river and presents a characteristic of the greater the discharge, the greater the reduction of sediment transport capacity. The horizontal geometric characteristics of sharp bends can be expressed by the product of the ratio of center angle and curvature radius to river width. In the flood stage, the cumulative effect of continuous bends on sediment transport capacity is that the horizontal geometric characteristics of sharp bends are negatively correlated with sediment transport capacity. In the recession stage, when the floodplain discharge is close to the bankfull discharge, the sediment transport capacity slightly recovers in local bends, and after the flow returns to the channel, the horizontal geometric characteristics of the bends and the sediment transport capacity return to a negative correlation again. [ABSTRACT FROM AUTHOR]

Different types of machine learning models have great differences in the prediction of groundwater arsenic. The existing machine learning models cannot simulate the spatial variation characteristics of groundwater arsenic pollution well. Based on 1081 measurements of arsenic concentration in shallow groundwater in northern Henan region of the Lower Yellow River, combined with human activities, climate, sedimentary environment, soil physical and chemical characteristics, hydrogeology and other environmental factors, this paper constructed a stacking integrated model with RF, XGBoost, SVM as the base learners and LDA as the meta learner to predict the spatial distribution of high arsenic groundwater in the study area, and identified the key environmental variables. The results show that arsenic concentration in groundwater in the study area ranges from 0.01 to 190 μg/L, and the excess rate is 16.74%. Comparing with RF, XGBoost and SVM, the Stacking integrated model has the maximum AUC, Accuracy, Specificity and Recall. The groundwater with high arsenic content is mainly distributed in the Taihang piedmont depression and the Yellow River rupture fan area, accounting for 33.81% of the total area. The Yellow River breach, the annual average temperature, annual precipitation, elevation and hydraulic gradient are the important environmental variables affecting the groundwater with high arsenic content in the study area. The comprehensive analysis shows that the sedimentary environment is significantly correlated with the arsenic enrichment in the groundwater. [ABSTRACT FROM AUTHOR]

Under the changing environment, the study puts forward the sediment disposal scheme that can maintain the stability of the lower reaches of the Yellow River and the floodplain to meet the requirements of the new situation, which plays an important guiding role in the control of the lower reaches of the Yellow River and even the watershed. Through the analysis of measured data and mathematical models, this paper analyzed the temporal and spatial distribution changes of sediment entering into the Yellow River. It is considered that after the completion of Sanmenxia Reservoir, the sediment discharge into the sea during the three reservoir operation stages is dominant, but after the completion of Xiaolangdi Reservoir, the sediment retaining in reservoir is dominant. Large reservoirs are important factors affecting the spatial distribution of sediment and the scouring and silting of the river channel. Under the scenario of 800 million to 300 million tons of incoming sediment of the Yellow River, the lower reaches of the Yellow River cannot achieve the stability of the river channel and the floodplain. Five sediment disposal schemes have been proposed. Through calculation, analysis and evaluation, the optimal scheme has been obtained, that is, Guxian and Taohuayu reservoirs plus floodplain ecological management scheme. The construction of Guxian Reservoir can basically realize that the riverbed of the lower reaches of the Yellow River will not be silted up for 50 years, and the floodplain ecological management can eliminate the secondary suspended river, in addition, the Taohuayu Reservoir can significantly improve the flood control standard for floodplain, so the comprehensive evaluation of the scheme is the best. [ABSTRACT FROM AUTHOR]

The Xiaolangdi Reservoir has been mainly used for sediment trapping and water-sediment regulating in order to reduce sedimentation of the lower Yellow River after operation, which results in lower sediment transport efficiency. At present, a suitable river channel scale of median water with the bankfull discharge capacity of 4 000 m³/s has been formed in the lower Yellow River. Under this riverbed condition, how to maintain the river channel of median water of the lower Yellow River and give full play to the river sediment transport capacity becomes new requirement to the operation of the reservoir. This paper analyzed the sediment transport efficiency at different sediment concentration levels and discharge levels based on the measured data of 306 non-overbank floods in the lower reaches of the Yellow River from 1960 to 2016 and proposed that the downstream river channel had a higher sediment transport efficiency when the large flow with sediment concentration greater than 60 kg/m³, but it was also prone to cause sedimentation in the river channel. The paper further proposed the sediment transport requirement to the operation of the reservoir based on maintaining the river channel of median water of the lower Yellow River. In order to improve the sediment transport capacity of the downstream river, when the bankfull discharge capacity of the downstream river channel was about 4 000 m³/s, the Xiaolangdi Reservoir could discharge large-flow processes with sediment concentration less than 100 kg/m³. When the bankfull discharge capacity of the downstream river channel was greater than 4 500 m³/s, the Xiaolangdi Reservoir could discharge large-flow processes with sediment concentration less than 200 kg/m³. When the bankfull discharge capacity of the downstream river channel was less than 4 000 m³/s in the future, the Xiaolangdi Reservoir would still mainly trap sediment to reinvent the river channel. The calculation results of the mathematical model show that the adjustment of the operation mode of the reservoir can improve the sediment transport capacity of the downstream river, alleviate the sedimentation of the reservoir and the downstream river and maintain the river channel of median water with the bankfull discharge capacity of 4 000 m³/s for a longer period of time. [ABSTRACT FROM AUTHOR]

This paper designed the village platform reconstruction plan according to the flood control standard of resisting the once-in-twenty-year flood. Based on the water and sediment data, land use type data and terrain data of floods of different return periods in the lower Yellow River, Delft3D software was used to establish a two-dimensional mathematical model of water and sediment, and the flood evolution of the Huayuankou-Aishan section in the lower Yellow River under the current plan of the village platform and the reconstruction plan of the village platform were simulated and calculated respectively. The results show that under the two schemes, with the increase of flood magnitude, the submerged area of floodplain and non-residential land is gradually increased. Compared with the current village platform plan, under the village platform reconstruction plan, the submerged area of floodplain and residential land is reduced, and the submerged area of non-residential land slightly increases, but the submerged water depth of floodplain and non-residential land is gradually increased, and the proportion of the area in which the submerged water depth of the residential areas is reduced is more than 95%. The village platform reconstruction plan can reduce the submerged area and submerged water depth of the residential area in the study area, and play a role in protecting the residential area. [ABSTRACT FROM AUTHOR]

In order to study the spatial characteristics of "three livings" in cities in the plain area of the lower Yellow River, and to guide the development of regional territorial space and ecological environment protection, through the establishment of the "three living" territorial space evaluation system, based on the "element-structure-function" framework, this paper analyzes Dezhou, Shandong Province. Spatial distribution characteristics of "three lives" in 12 streets (towns) in Shidecheng District in 2019. The results show that: for land element endowment, urban streets have a high level of diversification, a low degree of concentration, rich land use types, and mainly residential land, while suburban towns are on the contrary, and gradually transition to industrial and agricultural production land. Dominant; for the structural location, the urban residential land and non-agricultural production area of each sub-district in the urban area and Yuanqiao Town are significant, the agricultural production and rural residential area of suburban towns are significant, and the ecological land except Zhaohu Town is all It has locational significance; for the functional pattern, the production function is characterized by a gradient, the living function is weakened from the core area to the outside, the ecological function is high in the surrounding areas and low in the middle, and the "three-life" functional space is distributed in circles. [ABSTRACT FROM AUTHOR]

The river regime evolution of wandering channel includes not only gradual process but also mutation process. The sudden change of river regime refers to the large adjustment of the local or overall river regime in a short period of time in a wandering channel. The sudden change of river situation has brought major challenges to river flood control, water supply security and river governance. If the sudden change of river situation is properly utilized in some cases, it can effectively improve the control ability of the river regulation project and enhance the stability of the river situation. This paper reviews the research progress from the practical significance, connotation and research methods of the abrupt adjustment of the river situation of the wandering channel, points out the shortcomings of the existing research, and puts forward the problems that need to be paid attention to in the future research on the river situation abrupt change. Carry out the research on the sudden change of the river situation of the wandering channel to point out the direction. [ABSTRACT FROM AUTHOR]

There are nearly 100 irrigation areas with the area above 10 000 mu alongside the Lower Yellow River. Irrigation from the Yellow River has brought huge benefits to agriculture, but sedimentation in channels is very serious. The key reason is that there is no reliable formula to calculate sediment transport capacity in channels and the cross-section of channels is not determined according to hydraulic optimization, which leads to larger cross-section and lower flow velocity than that needed for equilibrium sediment transport. By introducing sediment transport equilibrium relationship using sediment grading in the Lower Yellow River and the optimization methods of channel cross-sections, it had been found in this paper that the sediment transport capacity in irrigation channels could be doubled. This optimized design would introduce theoretical basis for the improvement of irrigation channels mid transportation of sediment into farm fields, and it also provided new technical support for long-distance transport of high -concentrated sediment-laden from for the Yd.low River. [ABSTRACT FROM AUTHOR]

President Xi Jinping’s statement that “protecting the Yellow River is a strategy that will last for a millennium for the great rejuvenation of the Chinese nation” has raised a new topic for the regulation of theLower Yellow River, that is, drawing up a millennium blueprint for channel regulation. Fluvial geomorphology investigates the evolution of rivers under natural and human intervention conditions on a time scale of thousands of years, which supports long-term decision making on river management. Firstly, this paper introduced the history of fluvial geomorphology, its research contents, subject characteristics and issues of interest when applied to the practice of river management. Then, guided by the complexity theory of alluvial channel evolution and based on the methodology of “synthetic microanalysis”, the workflow of applied geomorphology that works for channel regulation of the Lower Yellow River was proposed. A demonstration of running the workflow was based on the geomorphologic researches on the Yellow River flood history over the past six millennia. By identifying the risk sources of course shift of the Lower Yellow River, reexamining the connotation of the existing channel regulation strategy, and evaluating the risk of course shift in the next three hundred years, a five-step blueprint for channel regulation in this millennium was proposed. Finally, the scientific issues that should be answered were listed. [ABSTRACT FROM AUTHOR]

Based on the measured data of flow and sediment of 304 floods from 1960 to 2010 in the lower Yellow River, the study on the regularity of flow-sediment movement during floods in the lower Yellow River was presented. The lower Yellow River was divided into four sections by the four hydrological stations(Huayuankou, Gaocun, Aishan and Lijin). The relationship between sediment transport rate at the four stations and the flow discharge, sediment concentration and sediment transport rate at their nearest upper station was analyzed. The results show that the sediment transport rate at a given station has a good relationship with that at its closest upper station. The finer relationship of sediment transport rate between a given station and its nearest upper station based on the grading of sediment coming coefficient(Q/S) at Xiaolangdi Station is further obtained. The calculated sedimentation amount for each section of the lower Yellow River by using the proposed relationship in this paper agrees well with the measured data. The relationship established in this paper can be easily used to estimate the sedimentation in the lower Yellow River during floods, which is significant for quickly evaluating the effect of reservoir operation upstream on river bed variation in the lower Yellow River. [ABSTRACT FROM AUTHOR]

This paper established a two?dimensional hydrodynamic model, verified the correctness of the model by water balance method and then applied it to analyze the effect of levee?breach width and roughness on flood routing in protected zone of the Yellow River. The results show that the effect of the roughness is small. The effect of levee?breach width is obvious, there is an obviously increase of inundated area and flood routing speed with the increase of levee?breach width. When the longer distance of flood routing and larger inundated area will be, the increase of levee?breach width will cause greater losses compared with the roughness in flood protected zone. Moved to close the breach as soon as possible can decrease losses. [ABSTRACT FROM AUTHOR]

The roads for flood control and production are complex and unsystematic in the floodplain area of the lower Yellow River, but they do not constitute a perfect transportation system, and the existing roads layout are difficult to provide effective traffic support for emergency traffic and emergency evacuation in flood season. Based on the analysis of current situation and existing problems of the roads layout in the floodplain area of the LYR, combining with the distribution of villages, the layout of flood control projects and practical problems of flood control in the floodplain area, this paper put forward the layout principles and design criteria of the roads. Meanwhile, the plane and longitudinal sections of roads were arranged based on the geographical conditions of typical floodplain area, the relationship between roads and the flood control works of the LYR was illustrated, directional suggestions were put forward for the roads construction in the floodplain area of the LYR in the future. [ABSTRACT FROM AUTHOR]

The large-scale circulation background, ambient field, triggering mechanism and mesoscale system of a severe torrential rainfall process with localized extremely severe rainstorm which occurred in the lower Yellow River during 3-4 August 2020 were analyzed in this paper based on the conventional observation data, minutely and hourly data of regional automatic stations, NCEP (U.S. National Environmental Forecast Center) 1°×1° reanalysis data and satellite cloud images. The results show that the typhoon landing, the strengthening of warm-humid airflow at the edge of the subtropical high and the influence of cold air are composed of the favorable ambient fields for producing heavy rainstorm. The formation and maintenance of ß mesoscale convective system (MßCS) is the direct cause of the severe rainfall. In the first stage of the severe rainfall, the updraft center is in the middle and upper levels, which is caused by the large and isolated MßCS of clouds. The ground convergence line and low-level cold air provides the trigger mechanism, and the water vapor mainly comes from the edge of the subtropical high and the southeast coastal area of China. In the second stage, the ascending movement center is in the middle and low levels. The formation of radial vertical circulation makes the ascending movement develop continuously. The heavy rainfall is caused by the MßCS formed by the merger of multiple convective cloud clusters. The gradient of TBB (Genting quite black body brightness temperature) is large, the ground convergence line and wind shear provides the trigger mechanism, and the water vapor mainly comes from the southeast coast. [ABSTRACT FROM AUTHOR]

The protection and utilization of water front is the essential part of ecological protection and high quality development of the Yellow River Basin. Focusing on the lower reaches of the Yellow River, this paper conducted a study on quantitative methods of water front protection and utilization, which could meet the new developing requirements. We scientifically determined the scope of Yuanyang water front on the basis of previous relevant research, and deeply analyzed the changes of land use structure of Yuanyang water front in 2000-2015 and its drive mechanisms in time and space. Then, we built a multi-objective optimization model after balancing economic, social and ecological benefits, in accordance with the multiple demands on flood control, economic development and ecological protection for Yuanyang water front. And further we predicted a scene plan of water front protection and utilization in 2025. The results demonstrate that this method is able to optimize the protection and utilization of Yuanyang water front in term of quantity and provide a wide range of scene plans with consideration of different emphasis on economic or ecological benefits. And it offers a quantitative method for water front exploitation of the Yellow River Basin. [ABSTRACT FROM AUTHOR]

Ecological protection and high-quality development of the Yellow River basin has become a major national strategy. From the perspective of ecosystem protection and river health maintenance, this paper analyzed and evaluated the effect of ecological management in the lower Yellow River. The results show that the ecological base flow, the ecological flow in the sensitive period, the functional maintenance of the ecological corridor and the wetland ecological flow in the important sections of the lower reaches are fully satisfied. Compared with the period of 2009-2010, the number of fish species detected in Henan section and Shandong section has been increased by 16 and 12 respectively. The wetland area of the downstream river has been increased by 7.2% compared with that of 2019. The representative wetland area of reed marsh in estuarine area reaches to 17,300 hectares, exceeding the level of 14,000 hectares when the nature reserve was established in the early 1990s, playing an important role in the protection and restoration of the ecosystem of the lower reaches and the Yellow River delta. At the same time, it also points out that ecological protection and restoration are a long-term process and puts forward some suggestions on deepening ecological regulation in the lower reaches of the Yellow River and strengthening effect evaluation. [ABSTRACT FROM AUTHOR]

The floods occurred in the lower reaches of the Yellow River has been the serious hidden danger for the Chinese nation. The flooding of the Yellow River and the shifting of river channel had posed a great threat to the life and property security of the people in the lower reaches. According to the record of historical literatures and combing of previous research results, this paper discussed the relationship between the river training works and the Yellow River floods in the Ming and Qing dynasties. The research shows that the river training works are obviously in response to the flood events in the Ming and Qing dynasties and there is a positive correlation between the river works and floods. The flood frequency of the Yellow River in the late Ming Dynasty is higher than that in the early period and the river training works also show a corresponding trend. In the early and middle Ming Dynasty, there are more frequent floods and more river engineering works in Henan area. In the late Ming Dynasty and Qing Dynasty, the flood occurred frequently in the area south of the lower reaches of the Yangtze River, the construction of river training works are also more frequent. The Yellow River floods have promoted the construction of river engineering works, which can effectively control the flood of the Yellow River. However, the most of the river works are built after burst or blocked, mainly belonging to post-disaster response types. [ABSTRACT FROM AUTHOR]

The demonstration research project of river regime control and beach arm control is an important link to make the national key science and technology research and development program of "Research on River Channel and Beach Area Control of the Lower Yellow River" achieve the final results and be popularized in the lower Yellow River. This paper presented the "steel shaped sheet pile dam for river potential control ", "upward-facing variable flow dam for siltation", " steel pipe and tire permeable pile dams to bundle the flow of sand", "Z-shaped sheet pile beach protection", "efficient sediment disposal", "steel pipe pile dam shore protection", "steel pipe and tire permeable pile integrated dams", " single row steel pipe permeable pile buffer to limit the flow" and other pilot project forms respectively on the basis of expounding the research objectives, implementation and the general situation of the demonstration river section. The implementation of these projects shows that they can not only achieve the expected purposes of river regime control and diversion, sediment promotion by changing flow, sediment transport by beam, beach protection and erosion prevention, and efficient sediment transport to meet the needs of local people, but also can increase the types of demonstration projects, expand the demonstration role and achieve better demonstration effect. In particular, it does not occupy the original farmland, effectively protects other cultivated land, makes it easy to enter and occupy, and does not need emergency maintenance. In addition, it can directly deposit vast beach land in the downstream, which is conducive to ecological restoration, and obviously can directly and indirectly produce huge economic, social and ecological benefits. [ABSTRACT FROM AUTHOR]

This paper analyzed the influencing factors of the decrease of water and sediment, the serious erosion of river bed and the serious collapse of fm·mland. It <thening the dike", which was inherited until today . c) In order to curb the collapse of fau-mland on " the second beach ", the research group of" demonstration project of river regime control and beach area treatment in the lower Yd.low River" built " steel tube wheel tire permeable pile: bunch flow sand transpm1 demonstration project" and "Z-type steel sheet pile shmJ protection demonstration project" on the opposite b.mk of the " steel sheet pile composite dam demonstration project" of the Xindianji centnJized control and guide projcx·t, which can become a feasible: countermeasure for sho

In the detection of dike hidden danger, geophysical method has the advantages of fast, economic and non-destructive. However, due to the complex structure of dike engineering and the complex distribution and types of hidden danger, the common single geophysical method has its limitations and shortcomings, which can not solve the problem of dike hidden danger distribution in an all-round way. In this paper, taking the hidden danger detection of a dike project in the lower Yellow River as an example, the comprehensive geophysical methods, such as geological radar method, high-density electrical method and surface wave method were used to detect the hidden danger. Different methods referred to each other and complement each other, so as to comprehensively solve the characteristics and distribution issues of the hidden danger. At the same time, it also provided some reference for the selection of methods to solve similar hidden danger detection issue. [ABSTRACT FROM AUTHOR]

This paper explained the logical relationships among subjects of the key project of National Key R & D Program of China that “Research on Managements of Channels and Beach Areas in the Lower Yellow River” and clarified the importance of the demonstration project. Following arguments, the demonstration project site was determined to be about 100 m below the proposed extended last spur dike of Xindianji Control Project in Dongming floodplain area. It could effectively prevent downslide of river regimes and avoid flood threat to the village platform under construction. Besides, it also could curb the downward trend of the river regime in the lower head of the Laojuntang Project by stabilizing the sites that flow touching the management structures. Furthermore, a new structure for river management and emergency rescue, namely the sheet pile combination technology was developed, which could realize different functions by adjustments of components spatially. By adopting the reinforced concrete panel hydraulic insertion technology in sinking piles, when the pile top was 3 m lower than the corresponding sheet, this design could deepen foundation, reduce effects on upper flow movement and promote sediment deposition between two piles. Also, the seawall built in the northern part of the Yellow River delta had withstood the test of storm surges. With the rapid developments of rust prevention and piling technology, reinforced concrete could be changed into steel structure in order to achieve the goal of accurate design. That is, prefabricating-assembling the Hbeam with wide flange and steel pipe into the “profiled sheet pile” element and adding overhanging-submerged anti-impact device on the facing water surface every 7.5 m, which more reflects the independent innovation of research and development technology. Thus, the demonstration project was optimized into the structural form of “steel sheet pile combined dam with overhanging flow changing and sediment silting device”. Finally, the technical details of component processing and construction were introduced. [ABSTRACT FROM AUTHOR]

Selenium，as one of the essential micronutrients is closely related to human health. In this paper，the contents of selenium and cad- mium， mercur^^，lead，arsenic，copper and chromium in the surface and deep layers of Yuanyang section in the floodplain area of the Lower Yellow River were obtained by sampling and analysis and the quality of selenium was evaluated. The results show that the selenium content in surface soil is 0.022-1.232 mg/kg and the average is 0.448 mg/kg，the selenium content in deep soil is 0.081-2.570 mg/kg and the average is 0.945 mg/kg. Generally，it belongs to medium and high selenium soil. Selenium deficient areas are mainly distributed in the west part of the studied area， while the areas with higher selenium content are mainly concentrated in the middle part and the distribution range of seleni- um in the surface and deep layers is consistent. The selenium content is mainly affected by soil parent material， pH and the organic matter. In addition， the contents of cadmium， mercury， lead， arsenic， copper and chromium are relatively lower and the soil environmental quality is good as a whole. [ABSTRACT FROM AUTHOR]

In recent years，the wandering channel in the low-er reaches of the Yellow River has been in the process of small discharge for a long time. This phenomenon will not only cause the collapse of the beach area，but also with the development of the defor^ned river course，it is possible to for^n the adverse river conditions such as horizontal flow and inclined flow，which will cause the risk of the mainstream directly rushing to the top of the levee. Since 2016，with the increase of the amount of water coming from the downstream flood season，the original abnormal river regime formed at the sections of Kaiyi-Zhaogou，Peiyu-Dayulan and Dong’ an-Taohuanyu have been eliminated under the natural hydraulic conditions and the river regime has been smooth gradually. However， the abnormal river regime in the section of Weitan still exists. Based on prototype investigation，model test and other means，this paper systematically analyzed the evolution law，of deformed river regime in Weitan section. According to the study，at present，the maximum flood peak discharge in the downstream of the Yellow River is generally about 4 000 m3/s during the water and sediment regulation and this abnor^mal river regime is difficult to be eliminated naturally in this water and sediment process. In order to achieve the required hydraulic conditions，the flood peak discharge needs to reach 10 000 m3/s. However， because the goal of water and sand regulation downstream is to protect the beach， it is suggested that artificial cutting of the beach should be adopted to carry out artificial cutting of the bend. [ABSTRACT FROM AUTHOR]

In order to speed up the information process of intelligent detection on the quality of flood control engineering works in the lower reaches of the Yellow River, the connotation of top-level design of intelligent quality detection of flood control project in the lower reaches of the Yellow River was put forward in combination with the internet of things, including the concept of top-level design and the unified problems that need to be solved in top-level design for quality intelligent inspection of hydraulic engineering. This paper put forward the general structure for intelligent quality inspection of flood control project in the lower reaches of the Yellow River, and briefly described the construction objectives, business processes, system functions, project technical routes and innovations of the quality inspection and management system of flood control project in the lower reaches of the Yellow River. The influence of intelligent detection on the quality detection and management of flood control project in the lower reaches of the Yellow River was analyzed, including the change of management characteristics and management system. Emphasis was placed on the transformation of management functions-process management as the main and function management as the supplement. The proposal of intelligent detection provides an important guarantee for the realization of information of quality inspection of flood control project in the lower reaches of the Yellow River. [ABSTRACT FROM AUTHOR]

Since the operation of Xiaolangdi Reservoir, the river bed of the lower Yellow River has been continuously scoured and cut down, and the water level of the same discharge has been lowered, which has a negative impact on the diversion capacity of the Yellow River diversion culvert gate. Affected by the change of boundary conditions of downstream riverbed, it is necessary to reconstruct part of the river bed. Location selection is the key point and key point of engineering design in the reconstruction project of culverts and sluices in the lower reaches of the Yellow River. Based on the study of the variation and influence of diversion flow and water level in the lower reaches of the Yellow River, this paper took Weishan sluice as an example, from the aspects of geology, flow conditions, siltation of diversion channels, temporary occupation of land for diversion channel silting and ecological environment, and its impact on the original buildings, the factors influencing the construction period were analyzed and demonstrated comprehensively and the gate site selection was determined. [ABSTRACT FROM AUTHOR]

The river regulation work of the lower Yellow River is a complex systematic project. It is not only influenced by those boundary conditions of societies, environments and incoming water and sediment volumes outside the system, but also restricted by the relations of floodplain and main-channel inside. In recent decades, many researchers have done much work from different layers and aspects on this issue. This paper introduced the research progress of the theory and technology on synergistic regulation for floodplain and main-channel of the lower Yellow River and put forward the strategy and methodology of synergistic regulation for floodplain and main-channel to adapt the future boundary conditions of nature, societies and environments, which might solve the conflict between flood prevention and social-economic development in the floodplain and achieve a harmonious state finally. [ABSTRACT FROM AUTHOR]

In order to comprehensively promote the protection and restoration of aquatic ecological environment, according to the arrangement of the Ministry of Water Resources, pilot work on ecological flow in the lower Yellow River had been carried out from 2016 to 2018 and the flow indicators of ecological function maintenance and ecological service demand in the Lower Yellow River had been studied. Taking 2018 Yellow River downstream ecological water regulation as an example, this paper analyzed the ecological regulation practice. Through the determination of the objectives and principles of ecological water quantity regulation, the research and implementation of the ecological water quantity regulation scheme and the analysis of the regulation effect were carried out. The results show that the practice of ecological water regulation in the Lower Yellow River has effectively increased the freshwater resources into the sea, increased the satisfaction degree of ecological flow, further increased the area of wetland in the lower reaches, maintained and improved the function of ecological corridor in the river course and promoted the protection and restoration of aquatic habitats of the Yellow River. [ABSTRACT FROM AUTHOR]

Erosion and deposition is depended mainly on oncoming water and sediment in the Lower Yellow River (LYR). It varies with changes of flow discharge and sediment concentration. The less sediment concentration is, the smaller ratio of deposition to oncoming sediment load is, and the larger water volume per unit for sediment transport will be. On the contrary, the higher sediment concentration is, the greater ratio and the less water volume will be. Under a circumstance of less water and more sediment, increasing shortage of water resources and contradiction between supply and demand, optimizing matches of oncoming flow and sediment and modeling floods of high efficient sediment transport can be carried out by reservoir regulation to reduce deposition and water volume for sediment transport. Based on typical floods of high efficient sediment transport in LYR, relationship between the ratio and water and sediment factors was established. A critical sediment concentration for erosion and deposition corresponding to discharge of 4,000 m3/s was 50 kg/m3. On the basis of flood and sediment transport pattern in the LYR, this paper analyzed the changes of water volumes per unit for sediment transport with changing of sediment concentration under restriction that the river channel maintained basically no deposition. Then, optimizing indices of flow and sediment for high efficient sediment transport were flood discharge of 4,000 m3/s, ratio of deposition to incoming sediment load of 0-15% and corresponding sediment concentration range from 50 to 75 kg/m3. [ABSTRACT FROM AUTHOR]

The paper is intended to address the effects of the abandoned Jing-Han railway bridge piers in the lower Yellow River upon the local plan-forms and propose for countermeasures. The study will be of significant implications in local flood fighting, restoring local ecological landscape and water diversion. The authors, using multiple-year field data of local channel plan-forms measured near the piers, analyzed the features and reasons for the near plan-form changes and the effects of the piers and made a suggestion for curing the negative consequences. First, the main stream touching the deflecting works in the reach near the abandoned Jing-Han Railway Bridge piers have been found shifting downstream, with the main stream thread tending to get straightened, consequently making the main stream out of touch with the several neighboring deflecting works. Second, the remaining piers and their supporting stone works have been found to act as a comb, resisting and spreading the local flow, affecting the plan-form significantly. Last, it is suggested that efforts should be made to remove the abandoned piers and ripraps in the range of 600 m within the channel regulating alignment lines, and dredge the neighboring reaches so that the main stream deflected from the upstream works can approach directly the receiving arm of the downstream works at Laotianan, getting deflected by the works, further downstream, at Baohezhai, Mazhuang and Huayuankou. [ABSTRACT FROM AUTHOR]

In view of the hislory of the Yellow River, there have been hyper concentration floods under the condition of channel scouring. Considering the powerful sediment transport capacity of hyper concentration floods, this paper studied the possibility of adopting hyper concentration floods mode to transport plenty of sediment in the lower reaches of the Yellow River, and made a quantitative analysis of the critical conditions of hyper concentration flow to achieve the equilibrium of SCOUling and silling and even the state of channel scouring. Quantitative calculation was carried out at the Huayiiaukou section, and the variation of relative sediment transport capacity was taken as the main physical quantity to carry out the analysis and comparison under different water and sand conditions. The results show that the hyper concentration floods under natural conditions in the balance of scouring and silting have certain particularities, especially the relationship lwtween gradation and sediment concentration might satisfy certain conditions with exchanging of suspended sediment and bed sediment along the river. In addition, the continuous duration of hyper concentration is one of the necessary conditions for long-distance sediment transjK)rt. [ABSTRACT FROM AUTHOR]

The paper sliow.s the suininar)' in the significant changes of the wandering Yellow River due to continuous low concentrated flow released from the Xiaolangdi Reservoir, which will lead to more in-depth understandings of the law governing the morphological changes of the wandering reach of the river and a proposal for their effective control. Analysis of the data of the river regime in the reach from Tiexie to Gao-cuii measured from 2000 to 2015 leads to the understandings. First, plan forms change in large scales and become more scattered with channel widths increased, in channel liars increased in number and abnormal bends becoming more apparent. Second, relative to a flow deflecting dike, the point where main channel flow attacked the dike shift downstream in the first half period and upstream in the second half. The regulating processes of the kind move from upstream to downstream. Last, it is proposed that the segments from Dong* an to Taohuayu, Sanguan-miao to Heigangkou and Baocheng to Qiugzhuang, which are found most likely to endanger the people living on the nearby floodplains, should be trained first and that high attention to any new slates should be paid so as to secure safety in flooding. [ABSTRACT FROM AUTHOR]

Floodplain is the important region for flood flowing, detention and desanding of the Yellow River as well as the surival home of 1.895 million people, so the contradiction between the economic and social development of floodplain and river management has become the focus of relevant departments in Shandong and Henan provinces. In this paper, the role of floodplain in flood sediment treatment, the functional changes of floodplain for flood detention and desanding, the utilization of floodplain in region and the industrial development and population relocation of the floodplain are summarized systematically and thus three main issues at the moment were pointed out： Firstly, there is a bigger controversial between the future sediment regime of the Yellow River and the strategic positioning of floodplain for desanding. Secondly, some issues like flood control and population relocation that restrict the industrial development of floodplain remain unresolved. Finally, study on synergy between construction of ecological civilization in floodplain and downstream flood control is insufficient. On the basis, sever¬al important research projects were proposed, including strengthen research on treatment direction from the strategic point of view, strengthen research on impact of different treatment schemes from the scheme point of view, strengthen research on key techniques of water and sediment trans¬port and channel change in the lower reaches and development advantage and potential of different floodplains from the technical point of view. [ABSTRACT FROM AUTHOR]

Sanliuzhai irrigation area is on the Lower Yellow River. The diversion condition of its sluices is good, hut the river channel erosion causes the river water level decline, having certain influences to the sluice diversion capacity. Using 2002-2013 Huayuankou Hydrologic Station’s discharge and water level data and Sanliuzhai irrigation area’s water diversion data, this paper analyzed and obtained that the Yellow River stage processes in the reach of Sanliuzhai water gate, water level and water flow relationship before the sluice and put forward the diversion discharge of Sanliuzhai sluice under multi-year average and incoming water frequency of 50% conditions. The multi-year average intake from the Yellow River (2007-2011 ) was 89.31 million m3 and intake from Yellow River is 83.95 million m3 in P- 50% water incoming year (2010). [ABSTRACT FROM AUTHOR]

The Lower Yellow River floodplain is a flood detention and desilting area, at the same time it is also the homeland of floodplain residents. There are still 915.8 thousand residents lack of security for flood control. The people live in poverty. The unfavorable channel pattern in the Lower Yellow River makes the Yellow River's flood control situation still severe. Fully considering the national ecological development strategy in the new era and the economic and social development requirements along the Yellow River, the paper put forward 5 specific modes for ecological reconstruction management of the Lower Yellow River floodplain and the detailed ways to implement them. The effect of ecological management was evaluated from flood control, safety of residents in beach area, ecology and economy. The results show that the management has significant effects on economy, society and ecology. It is suggested that the state should accelerate the work of the ecological management. [ABSTRACT FROM AUTHOR]

The Yellow River, as the mother river in China, accounts for 2% of the national runoff volume which undertakes the water-supply task for 15% of the national cultivated area and 12% of population simultaneously. Also, the Yellow River has the maximum sediment in this world, and thus enough water volume is needed in the channel for sediment discharge into the sea, in addition, about 10 billion m3 must be supplied by the Yellow River for the regions along the Yellow River outside the basin, which all makes the contradiction between water supply and demand extremely sharp. With the development of social economy, water utilization volume is on the increase and ecological water volume is heavily occupied causing a series of ecological problems such as drying-up river channel, riverbed sedimentation and water pollution. Study on the ecological water volume of the Yellow River is always the research focus and the major issue. Therefore, based on the characteristics of runoff and sediment in the Yellow River, water balance method and numerical method of groundwater simulation were employed to analyze the water leakage volume of river channel and its ecological effects. The results imply that the partial water volume losses should be considered in the ecological water volume in the main stream of the Yellow River. Through the research in this paper, the study thoughts and means for the ecological water volume of the lower Yellow River was further improved, which could provide the decision-making basis for the ecological system maintain, ecological operation of water resources and basin management of the Yellow River. [ABSTRACT FROM AUTHOR]

Ｔｈｅ ｌｅｖｅｅｓ ｏｆ ｔｈｅ Ｌｏｗｅｒ Ｙｅｌｌｏｗ Ｒｉｖｅｒ ａｒｅ ｓｕｂｊｅｃｔ ｔｏ ｓｅｅｐａｇｅ ｄａｍａｇｅ ｄｕｅ ｔｏ ｔｈｅ ｌｏｗｅｒ ｃｌａｙ ｃｏｎｔｅｎｔ， ｉｎｈｏｍｏｇｅｎｅｏｕｓ ｓｏｉｌ， ｐｅｒｍｅａｂｌｅ ｓｔｒａｔａ ｉｎ ｔｈｅ ｌｅｖｅｅ ｆｏｕｎｄａｔｉｏｎ ａｎｄ ｍａｎｙ ｐｉｔｓ ａｎｄ ｄｉｔｃｈｅｓ ｎｅａｒ ｔｈｅ ｌｅｖｅｅ ｌａｎｄｗａｒｄ ｓｌｏｐｅ． Ｗａｒｐｉｎｇ ｉｓ ｏｎｅ ｏｆ ｔｈｅ ｍａｊｏｒ ｍｅｔｈｏｄｓ ｔｏ ｒｅｉｎｆｏｒｃｅ ｔｈｅ ｌｅｖｅｅ ａｎｄ ｍｉｔｉｇａｔｅ ｓｅｅｐａｇｅ ｄａｍａｇｅ ｉｎ ｔｈｅ Ｌｏｗｅｒ Ｙｅｌｌｏｗ Ｒｉｖｅｒ ｗｈｉｌｅ ｔｈｅ ｗａｒｐｉｎｇ ｗｉｄｔｈ ｉｓ ａ ｋｅｙ ｉｎｄｅｘ． Ｔｈｒｅｅ ａｓｐｅｃｔｓ ｗｅｒｅ ｔａｋｉｎｇ ｉｎｔｏ ｃｏｎｓｉｄｅｒａｔｉｏｎ ｉｎ ｄｅｔｅｒｍｉｎａｔｉｏｎ ｏｆ ｔｈｅ ｗａｒｐｉｎｇ ｗｉｄｔｈ ｉｎ ｔｈｉｓ ｐａｐｅｒ． Ｆｉｒｓｔｌｙ， ｔｈｅ ｓｔａｔｉｓｔｉｃａｌ ｄａｔａ ｏｆ ｌｅｖｅｅ ｓｅｅｐａｇｅ ｉｎ ｔｈｅ ｈｉｓｔｏｒｙ ｏｆ Ｌｏｗｅｒ Ｙｅｌｌｏｗ Ｒｉｖｅｒ ｓｈｏｗｅｄ ｔｈａｔ ８５％ ｓｅｅｐａｇｅ ｄａｍａｇｅ ｄｉｓｔａｎｃｅ ｗａｓ ｌｅｓｓ ｔｈａｎ ５０ ｍ （ｆｒｏｍ ｔｈｅ ｌｅｖｅｅ ｔｏｅ ｔｏ ｔｈｅ ｄａｍａｇｅ ｐｏｉｎｔ） ａｎｄ １４％ ｗａｓ ｂｅｔｗｅｅｎ ５０ ｍ ａｎｄ １００ ｍ． Ｓｅｃｏｎｄｌｙ， ｄｏｍｅｓｔｉｃ ｒｅｓｅａｒｃｈ ｒｅｓｕｌｔｓ ｏｆ ｗａｒｐｉｎｇ ｗｉｄｔｈ ｒｅｃｏｍｍｅｎｄ ｔｈａｔ ｔｈｅ ｗａｒｐｉｎｇ ｗｉｄｔｈ ｉｎ ｔｈｅ Ｌｏｗｅｒ Ｙｅｌｌｏｗ Ｒｉｖｅｒ ｓｈｏｕｌｄ ｂｅ ｍｏｒｅ ｔｈａｎ １００ ｍ． Ｔｈｉｒｄｌｙ， ｌｅｖｅｅ ｗｉｔｈ ｗａｒｐｉｎｇ ｗｉｄｔｈ ｂｅｔｗｅｅｎ ８０ ｍ ａｎｄ １００ ｍ ｈａｄ ｌｅｓｓ ｓｅｅｐａｇｅ ｄａｍａｇｅ ａｃｃｏｒｄｉｎｇ ｔｏ ｌｅｖｅｅ ｓｅｅｐａｇｅ ｓｔａｂｉｌｉｔｙ ｃａｌｃｕｌａｔｉｏｎ． Ｂａｓｅｄ ｏｎ ｔｈｉｓ ａｎａｌｙｓｉｓ， ｔｈｅ ｓｃｉｅｎｔｉｆｉｃ ｗａｒｐｉｎｇ ｗｉｄｔｈ ｏｆ ｌｅｖｅｅ ｉｎ ｔｈｅ Ｌｏｗｅｒ Ｙｅｌｌｏｗ Ｒｉｖｅｒ ｉｓ ｂｅｔｗｅｅｎ ８０ ｍ ａｎｄ １００ ｍ． [ABSTRACT FROM AUTHOR]

Land use in the beach area of the Lower Yellow River is closely related to the production and life of the people in the beach area and the safety of flood control in the lower reaches of the Yellow River. This paper summarized the investigation and change of land use in the beach area of the lower Yellow River in recent years, the different viewpoints of land use and flood control safety, and the many solutions of "people and water competing for land", analyzed the new trend of land use of floodplain immigrants, and finally proposed to strengthen the unified planning of land use and flood control in beach area. Objective to provide new ideas and references for the development and utilization of land in the Yellow River beach area and the control of the Yellow River. [ABSTRACT FROM AUTHOR]