Yellow River Conservancy Commission Research Articles

Spatial and temporal characteristic of PM2.5 and influence factors in the Yellow River Basin.

The Yellow River Basin has been instrumental in advancing ecological preservation and fostering national high-quality development. However, since the advent of China's reform and opening-up policies, the basin has faced severe environmental pollution issues. This study leverages remote sensing data from 1998 to 2019. As per the "Basin Scope and Its Historical Changes" published by the Yellow River Conservancy Commission of the Ministry of Water Resources, the Yellow River Basin is categorized into upstream, midstream, and downstream regions for analysis of their spatial and temporal distribution traits using spatial autocorrelation methods. Additionally, we employed probes to study the effects of 10 factors, including mean surface temperature and air pressure, on PM2.5. The study findings reveal that (1) the annual average concentration of PM2.5 in the Yellow River Basin exhibited a fluctuating trend from 1998 to 2019, initially increasing, then decreasing, followed by another increase before ultimately declining. (2) The air quality in the Yellow River Basin is relatively poor, making it challenging for large-scale areas with low PM2.5 levels to occur. (3) The PM2.5 concentration in the Yellow River Basin exhibits distinct high and low-value concentration areas indicative of air pollution. Low-value areas are predominantly found in the sparsely populated central and southwestern plateau regions of Inner Mongolia, characterized by a better ecological environment. In contrast, high-value areas are prevalent in the inland areas of Northwest China, with poorer natural conditions, as well as densely populated zones with high energy demand and a relatively developed economy. (4) The overall population density in the Yellow River Basin, as well as in the upstream, midstream, and downstream regions, serves as a primary driving factor. (5) The primary drivers in the middle reaches and the entire Yellow River Basin remain consistent, whereas those in the upper and lower reaches have shifted. In the upstream, air pressure emerges as a primary driver of PM2.5, while in the downstream, NDVI and precipitation become the main influencing factors.

Cross-regional ecological compensation under the composite index of water quality and quantity: A case study of the Yellow River Basin

The calculation of ecological compensation (EC) constitutes the core element of the EC mechanism, which is related to the practicability of the mechanism. Based on the comprehensive index of water quality and quantity, this study establishes a measurement method for EC across administrative divisions. First, the improved Nemerow pollution index (NPI) is adopted to assess the water quality of specific sections, while the water rights and GDP indicators are employed to characterize the water quantity of each section. Secondly, given the spatial relationship of each region within the basin, two compensation allocation schemes are established referring to the water intake and grey water footprint indicators. Finally, the EC amounts of each region in the Yellow River Basin from 2016 to 2021 are calculated using the proposed method. The results show that: (1) the improved NPI is significantly higher in the upstream than in the downstream, implying better water quality in the upstream region; (2) From 2016 to 2021, both Gansu and Ningxia exhibit negative EC coefficients, suggesting superior water quality in the upper section of these regions, while Henan Province demonstrates the opposite trend; (3) During the same period, Qinghai, Gansu, Shanxi, Shaanxi, and Shandong experience an EC deficit, while Ningxia, Inner Mongolia, Henan, and Yellow River Conservancy Commission exhibit an EC surplus. Using water quality and quantity indicators, this study includes the implementation of basin unification and regional environmental comprehensive management into the scope of responsibility of the basin government, which can effectively solve the drawbacks of unclear responsibilities of stakeholders and ineffective implementation of compensation in the basin EC.

Function and crisis of the Nationalist Yellow River flood control system in wartime China

ABSTRACT The water management of the Yellow River was subsumed under the wartime system of the Nationalist government since the beginning of China’s national resistance against Japanese aggression in 1937. The Yellow River Conservancy Commission, responsible for disaster prevention and economic exploration of the river, was on the one hand affiliated to the Ministry of Economic Affairs under the aegis of the Executive Yuan, while on another hand it was under the supervision of the First War Zone Command. The three parties above were closely related in all practical work and formed a complex operation mode which caused the water management in the flooded area to be riddled with difficulties and omissions. To be specific, albeit nominally unified, it functioned separately in its military, financial, and personnel management branches, and there was a lack of clarity in the responsibility of its three components. This resulted in chaotic circumstances, all parties impeding each other and denying responsibility. This situation reflected the serious deficiencies of the wartime system of the Nationalist government in various regards, such as in its functions, values, and administrative capacities.

Can Reservoir Regulation Along the Yellow River Be a Sustainable Way to Save a Sinking Delta?

AbstractToday's deltas are impacted negatively by (1) accelerated subsidence (e.g., from ground fluid extraction), (2) global eustatic sea level rise, and (3) decreased sediment supply, which increasingly starves these landforms of sediment necessary to sustain their footprint. This growing vulnerability threatens many megacities that have developed due to the rich resources offered by deltas and therefore urgently calls for efforts to maintain sustainability. The Yellow River of China is classic example of such a landform under threat and which requires human intervention to maintain its resilience. Since 2002, the Yellow River Conservancy Commission has enacted an annual water and sediment regulation scheme (WSRS) by coordinated operation of three large reservoirs in the mainstream. Here we evaluate the efficiency and sustainability of this man‐made experiment on delta evolution. The impulsive delivery of muds and sands, within ~20 day intervals (averaged duration of the WSRS), did indeed move the present Yellow River delta from a destructive phase to an accretion phase. With continuous scouring, however, the downstream riverbed erosion efficiency has decreased, due to coarsening of surface bed material sediment. Concomitantly, sediment delivery has decreased, resulting in the present delta once again entering an erosive (destructive) phase, since 2014. From a perspective of delta restoration, the WSRS on the Yellow River is effective but potentially unsustainable. Restoring delta resilience necessitates an enhanced, coordinated effort, relying upon new sciences advances, rather than simply assuming channel scour will address the sediment deficit of the delta.

Optimal water distribution system based on water rights transaction with administrative management, marketization, and quantification of sediment transport value: A case study of the Yellow River Basin, China

Water rights transaction has proved to be an effective method for constructing an efficient water distribution system (WDS) in various regions of the Yellow River Basin (YRB). In this study, an optimal WDS in the YRB is proposed by considering the comprehensive value of water resources, administrative management system, and market-based system. To accurately quantify the comprehensive value of water resources, the work analysis method of suspended load and bedload based on the emergy theory and time-averaged motion equation is introduced, and the quantification process of sediment transport value in the river course is formulated in the YRB. Based on this, an administrative and market-based game for water rights transaction is formulated. In this double-layer game model, the administrative authorities of the basin (Yellow River Conservancy Commission) and the corresponding regions (Water Resources Department) seek to maximize their own target revenue function/comprehensive value of the water resources. Then, the optimal trading quantity of water in each region and the bargain price can be solved. A case study is presented in the YRB to verify the effectiveness of this method. The results reveal that (1) the error rate of the riverbed shear stress as well as the sediment transport rate between the theoretical value and the calculated value does not exceed 8.76%, which indicates the rationality of the calculation method of sediment transport value; (2) the proposed dynamic differential game and pricing game perform well in determining the optimal trading quantity of water in each region. They also reveal the bargain price with optimal results of ¥ 4151.1456 half yearly and ¥ 8197.3466 per year in 2018, outperforming other methodologies.

Crucial role of natural processes in detecting human influence on evapotranspiration by multisource data analysis

Estimation of human-induced evapotranspiration (ET) changes (e.g., irrigation) is critical for understanding terrestrial water and energy cycle in the Anthropocene. A few studies have detected human influence on ET through comparing natural ET from reanalysis models and actual ET estimated by the water budget analysis with Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage data. However, whether models can reasonably reproduce natural hydrological processes is overlooked. Here we show that uncertainty in model-simulated natural ET can determine whether the human-induced ET change is detectable. The naturalized runoff provided by the Yellow River Conservancy Commission is used to calibrate the Variable Infiltration Capacity (VIC) model to obtain a more reliable estimation of natural ET. The actual ET is estimated by either using the GRACE satellite retrievals with coal mining-induced gravity change removed, or 192 soil moisture station observations combined with surface and ground water resources bulletin data over the Yellow River basin. By comparing with natural ET from VIC simulations, human-induced annual ET changes are 41 ± 23 to 59 ± 31 mm/year during 2003–2010 for GRACE and soil moisture-based estimations respectively, contributing to 11%–16% increase in annual ET over the Yellow River basin. The estimation is comparable to the bulletin data of 47 mm/year. There is an obvious overestimation in natural ET from Global Land Data Assimilation System, prohibiting the detection of anthropogenic influence. This study highlights the importance of reasonably modeling natural hydrological processes as a baseline for detecting anthropogenic influence on the hydrological cycle.

Ice flood velocity calculating approach based on single view metrology

Yellow River is the river in which the ice flood occurs most frequently in China, hence, the Ice flood forecasting has great significance for the river flood prevention work. In various ice flood forecast models, the flow velocity is one of the most important parameters. In spite of the great significance of the flow velocity, its acquisition heavily relies on manual observation or deriving from empirical formula. In recent years, with the high development of video surveillance technology and wireless transmission network, the Yellow River Conservancy Commission set up the ice situation monitoring system, in which live videos can be transmitted to the monitoring center through 3G mobile networks. In this paper, an approach to get the ice velocity based on single view metrology and motion tracking technique using monitoring videos as input data is proposed. First of all, River way can be approximated as a plane. On this condition, we analyze the geometry relevance between the object side and the image side. Besides, we present the principle to measure length in object side from image. Secondly, we use LK optical flow which support pyramid data to track the ice in motion. Combining the result of camera calibration and single view metrology, we propose a flow to calculate the real velocity of ice flood. At last we realize a prototype system by programming and use it to test the reliability and rationality of the whole solution.

Fluvial processes of the downstream reaches of the reservoirs in the Lower Yellow River

Evolution of the river channel downstream of reservoirs is a complex process that is closely related to the operational mode of the reservoirs and the channel boundary conditions. Numerous studies have been carried out on the fluvial processes of downstream reservoirs. However, only a few of them have focused on the relationship between runoff-sediment conditions and channel pattern indicators. Also, the impacts of river training works on fluvial processes are seldom dealt with. In this paper, the evolutionary processes of three sections in the Lower Yellow River, including Tiexie-Yiluo River mouth reach, Huayuankou-Heigangkou reach and Jiahetan-Gaocun reach, were analyzed for variations in the channel boundary line and the mainstream between 1960 and 2015. Channel pattern indicators such as sinuosity, mainstream wandering range and width/depth ratio were analyzed based on field measurements obtained by the Hydrological Department of the Yellow River Conservancy Commission. The effects of river training works on the channel evolution are then described. Since 1960, numerous medium- and large-sized reservoirs have been built on the Yellow River, including Longyangxia Reservoir, Liujiaxia Reservoir and Xiaolangdi Reservoir. These reservoirs impound the runoff from upstream and retain the sediment, which changes the runoff and sediment conditions in the downstream reach. As a consequence, annual runoff and the frequency and peak of flooding have all decreased. As a result, the flow dynamics and their action on the river channel are also reduced, which changes the dynamic state of the river course. The discrimination results obtained using the single parameter discrimination rule and the discrimination equation show that the degree of wandering is weakened in the reaches studied. The variations in the channel pattern indicators show that the sinuosity increases and the wandering range decreases with a reduction in the total annual volume of water. However, the degree of wandering has little relationship to the sediment concentration. In addition, river training works play an important role in controlling the river course. Due to improvements in the river training works, the river course has become more stable under the same runoff and sediment conditions. A new discrimination rule that takes into account the impacts of the river training works is proposed. The discrimination results were found to fit well with the actual river pattern, which shows that the discrimination rule is applicable to the Lower Yellow River. The results show that the runoff and sediment conditions are the most important factors in the evolution of the river course. The river training works have at the same time limited the wandering range of the mainstream and played an important role in the fluvial processes. Both factors combined lead to the stabilization of the river.

Modeling Extreme Flood Events in the Yellow River Using Unstructured Grids

Abstract. Severe flood events in China are a common cause of life losses. Many efforts have been carried out by the Yellow River Conservancy Commission (YRCC) to understand flood development and impact on the Yellow River. Modeling approaches based on discretization of the modeled domain in square and rectangular grids have great importance in the management of rivers, but they usually present two drawbacks: the required accuracy of the meandering of wide long rivers is not well represented, and the need to use many grid cells reduces computational speed. Modeling and simulation of extreme flood events using unstructured grids has not yet been applied to the Yellow River. This study shows how such a method can be beneficial to decision makers in the Yellow River region in case of flood events. The research shows that a flexible mesh discretization of the domain can overcome the two drawbacks. Along with a test of the proposed modeling method, new characteristics of the spatial evolution of flood events in the Yellow River emerged and are presented, showing the capabilities of DFLOW-FM software in modeling such a complex system.

Impacts of climate variability and changes on domestic water use in the Yellow River Basin of China

We present a methodology for using a domestic water use time series that were obtained from Yellow River Conservancy Commission, together with the climatic records from the National Climate Center of China to evaluate the effects of climate variability on water use in the Yellow River Basin. A suit of seven Global Circulation Models (GCMs) were adopted to anticipate future climate patterns in the Yellow River. The historical records showed evidences of rises in temperature and subsequent rises in domestic water demand in the basin. For Upstream of Longyangxia region, the impact was the least, with only 0.0021 × 108 m3 for a temperature increase of 1 °C; while for Longyangxia-Lanzhou region, domestic water use was found to increase to 0.18 × 108 m3 when temperature increases 1 °C. Downstream of Huayuankou was the region with the most changes in temperature that gave the highest increase of 1.95 × 108 m3 in domestic water demand for 1 °C of change of temperature. Downstream of Huayuankou was identified as the most vulnerable area, where domestic water demand increases nearly by 42.2 % with 1 °C increase of temperature. Judging from the trends of temperature range, we concluded that future temperature in Yellow River Basin has an increasing tendency. This could worsen the existing issues of domestic water demand and even more to trigger high competition among different water-using sectors.

Application of One-Dimensional Hydraulic Model for Flood Simulation in Yellow River Delta

Yellow River Delta had been extensively engineered to control flooding and to protect coastal development which leaded to wetlands destruction and severe water pollution. The Yellow River Conservancy Commission decided the water supplement to the wetland during the water and sediment regulation period in 2010. In order to study the water quantity and distribution simulation, one-dimensional SOBEK model was used to flood simulation in the Yellow River Delta. The Re of the daily water level at four stations for the calibration period were 0.6%, 2.3%, 2.9%, 7.0%,.which indicated that the simulated values matched very well with the observed values. The SOBEK model had predicted the water level volume in 2003 within the range of acceptable accuracy. It indicated that the one-dimensional method SOBEK model was suitable for the flood simulation.

Challenges in modelling river flow and ice regime on the Ningxia–Inner Mongolia reach of the Yellow River, China

Abstract. During winter the Yellow River in China is frequently subjected to ice flood disasters. Possible dike breaking due to ice floods poses a serious threat to the part of the region located along the river, in particular the Ning–Meng reach (including Ningxia Hui and the Inner Mongolia autonomous regions). Due to its special geographical location and river flow direction, the ice dams and jams lead to dike breaking and overtopping on the embankment, which has resulted in huge casualties and property losses throughout history. Therefore, there is a growing need to develop capability in forecasting and analysing river ice floods. Research into ice floods along the river is taking place at the Yellow River Conservancy Commission (YRCC). A numerical model is one of the essential parts of the current research going on at the YRCC, which can be used to supplement the inadequacies in the field and lab studies which are being carried out to help understand the physical processes of river ice on the Yellow River. Based on the available data about the Ning–Meng reach of the Yellow River, the YRCC river ice dynamic model (YRIDM) has been tested for capabilities to conduct ice flood forecasting. The YRIDM can be applied to simulate water level, discharge, water temperature, and ice cover thickness under unsteady-state conditions. Different scenarios were designed to explore the model uncertainty for two bounds (5 and 95%) and probability distribution. The YRIDM is an unsteady-state flow model that can show the basic regular pattern of ice floods; hence it can be used as an important tool to support decision making. The recommendation is that data and research should be continued in order to support the model and to measure improvements.

Effect of Ecological Water Supplement on Land Use and Land Cover Changes in Diaokou River

Diaokou River is one of the old courses of the Yellow River access to the sea before 1976 and its estuarine delta is an important part of National Nature Reserve of Yellow River Delta. The Yellow River Conservancy Commission decided the ecological water supplement to the wetland during the water and sediment regulation period in 2010. In this study, we analyzed the land use and land cover changes before and after the ecological water supplement in Diaokou River by using HJ-1B CCD data. The impact of the ecological water supplement on land use and land cover changes in Diaokou River was remarkable. The expansion of shrub-grassland and water body at large scale is conspicuous, while decreasing areas of shallows was 15.03 km2 and unutilized land decreasing amplitude was 28%. The main area of land use change was in Yiqianer protected areas, where concentrated in the estuary of the Diaokou River.

Decentralized Optimization Method for Water Allocation Management in the Yellow River Basin

The management of large river basins, such as the Yellow River Basin (YRB) in China, is complicated by distributed, localized decision processes and by mechanisms that coordinate local decisions and manage basin-level issues. Since 1998, the Yellow River Conservancy Commission (YRCC) has launched the Unified Water Flow Regulation (UWFR) as a centralized controlling mechanism that enforces an upper limit on water withdrawals (water use permits) for eight provinces located in the basin. The implementation of UWFR has maintained a prescribed minimum flow in the downstream channel and avoided the flow cutoff events that occurred every year between 1972 and 1998. This study attempts to explore the socioeconomic and environmental consequences of the regulation and test plans to improve water allocation management in the YRB. A decentralized optimization is combined with a multipleagent system (MAS) framework for the YRB, in which water users, reservoirs, and downstream ecological zones are defined as agents. This method iteratively determines water prices for each water use agent in the context of water market. The proposed water market scenario shows possible improvements of UWFR with respect to social, economic, and environmental objectives. DOI: 10.1061/(ASCE)WR.1943-5452.0000199. © 2012 American Society of Civil Engineers. CE Database subject headings: River basins; Optimization; Water supply; Pricing; China; Water allocation policy. Author keywords: River basin management; Multiple agent system (MAS); Disaggregated optimization; Water price; Water market; Yellow River Basin.

Model of water-sediment regulation in Yellow River and its effect

Water-sediment regulation of the Yellow River is to regulate and control the flow and sediment transport relationship of the lower reaches through reservoirs on the main streams and tributaries to create balance between water and sediment so that sediment transport capacity of the downstream channels can be maximized, shrinking of channels be contained, and medium flood channel be restored and maintained. Many years’ research by the Yellow River Conservancy Commission (YRCC) reveals the water and sediment transport relationship that will prevent sedimentation at the downstream river channels. Based on this relationship and coming sediment and water conditions in the Yellow River basin, the YRCC, with maximized use of reservoirs on the main streams and tributaries, has developed three models of water-sediment regulation: single Xiaolangdi Reservoir-dominated regulation, space scale water-sediment match, and mainstream reservoirs joint operation. Ten water-sediment regulations based on these three models have resulted in an average drop of 1.5 m in the main channel of the downstream 800 km river and an increase of carrying capacity from 1800 to 4000 m3/s. Besides, the wetland ecosystems of estuarine delta has also been improved and restored significantly.

A 3-D numerical study of salinity variations in the Bohai Sea during the recent years

Salinity is an important component of the marine system. Previous studies indicated that the mean salinity in the Bohai Sea had increased by 2.0 psu in the second half of the 20th century, mainly due to a sharp decrease in the Yellow River runoff, and also the effects of large-scale climatic variations and the intrusions of the North Yellow Sea Water (NYSW). Since 2002, the Yellow River Conservancy Commission has carried out the flow regulation at the beginning of every flood season, resulting in more discharge of the Yellow River freshwater into the Bohai Sea. In this study, the variations of salinity in the Bohai Sea during the recent years are investigated using a well-established three-dimensional baroclinic model, HAMburg Shelf Ocean Model (HAMSOM). The simulation results show that the Yellow River diluted water was mainly discharged into the Laizhou Bay, so the remarkable increase in the Yellow River runoff after 2002 led to a regime shift of salinity in the Laizhou Bay. However, in other parts of the Bohai Sea, salinity variation was influenced by the surrounding rivers or the intrusions of NYSW, and has little relation with the Yellow River runoff. As a whole, advection is more important than diffusion in the salinity distribution, and seasonal oscillation is the main feature of salinity variation. Via several case studies, evaporation and precipitation rates are found to be important in the long-term simulation of salinity.

The velocity of the collective motion of sedimentation of sand and clay

In this article, we shall discuss the velocity of the collective motion of sedimentation when the concentration of clay particles is very high. We believe that the problem of the so-called velocity of the collective motion of sedimentation is not a real problem of sedimentation in physical nature, but it is a problem of filtration in the porous medium which is composed of colloidal clusters. That is to say, those clusters consist of water and clay particles. It is a problem of the water passing through the porous medium. Based upon this consideration, we put down the mathematical expression of the velocity of the collective motion of sedimentation. In comparing with the theoretical curves with the experimental data of the Institute of Hydraulic Research, of the Yellow River Conservancy Commission, we get congruous results.

The mechanical properties of the slurry and the resistance force of a sphere moving with uniform velocity in the slurry

It is commonly considered that the mechanical properties of the slurry are different from that of ordinary Newtonian fluid, and can be described by that of Bingham fluid. Hence its shearing stress should be described by the formula of the shearing stress of Bingham fluid. But the author holds the contrary opinion and firmly believes that the slurry is a highly viscous fluid with very long relaxation time such as those of asphalt, glass, etc. In this article, we have discussed the mechanical properties of the slurry and the resistance of a sphere moving with uniform velocity in the slurry. In the process of discussion, we use Stokes solution of the viscous fluid passing around a sphere. When the sphere is in equilibrium under the action of gravitational force, the force of buoyancy and the resistance, we get the velocity of sedimentation. When the velocity of sedimentation is equal to zero, we get the relation between the yield stress of Bingham fluid and the diameter of the particles which will not sink. The theoretical results calculated are compared with the experimental data of Northwest Institute of Hydrotechnical Research and Institute of Hydraulic Research, Yellow River Conservancy Commission. They are congruous.