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The practice of water right transfer in the Yellow River has been nearly 20 years. It is necessary to scientifically evaluate the implementation effect of water right transfer to provide technical support for the subsequent decision making of water right transfer. In this paper, on the basis of thorough analysis of water right transfer characteristics, two-layer and six-dimensional theoretical framework system of post-evaluation of the Yellow River water rights was built, including policy implementation effect evaluation and process evaluation as the first layer, and water-saving effect, social effect, economic effect and ecological effect, policy system, water saving project construction and operation maintenance 6 dimensions. The selection principles of indicators were clarified including in accordance with the Yellow River reality, correlation, measurability, qualitative and quantitative combination, absolute and relative combination. The evaluation indicators under each dimension were determined. A set of post-evaluation indicators system of water right transfer, consisting of 16 first-level indicators and 43 second-level indicators, reflecting the characteristics of the Yellow River was constructed. Application cases in Inner Mongolia region show that the index system is scientific and reasonable, and can guide the practice of similar area. [ABSTRACT FROM AUTHOR]

As one of the most serious natural disasters in arid and semi-arid regions, drought has brought about a series of natural ecological and socio-economic problems. Comprehensively considering multi-element information to analyze the drought’s temporal and spatial characteristics is of important guiding significance. Therefore, this paper comprehensively considered the three climatic elements of precipitation, evaporation, and runoff. It used standardized precipitation index, standardized precipitation evapotranspiration index, and standardized runoff index to calculate meteorological and hydrological droughts, and used principal component analysis to build a comprehensive Wuding River Basin drought index. On this basis, the information diffusion method was used to classify the comprehensive drought grades of the basin, so as to evaluate the temporal and spatial distribution characteristics of multi-scale drought events in the Wuding River Basin. The results show that on the interannual scale, the frequency of drought in the Wuding River Basin in 60 s is higher, followed by 1970 s-1980 s, and the smallest in 1990 s. In terms of time, on the intra-annual scale, the frequency of drought in April is the largest, and the drought in December is the smallest. Drought events are mostly concentrated in the period from June to August, and extreme drought is prone to occur from November to December; spatially, the inter-annual drought frequency of the basin varies significantly, and the spatial distribution of drought frequency in different months of the year is different. [ABSTRACT FROM AUTHOR]

Large-scale irrigation area reconstruction and expansion projects involve the repair, reconstruction and new construction of sluices, channels, inverted siphons, aqueducts and other structures. In order to ensure the quality of the project and avoid the occurrence of safety accidents, it is necessary to explore, prevent and control the hazards that may lead to building quality defects and safety accidents during the construction period. Using the work breakdown structure method and the analytic hierarchy process, the paper took the sluice engineering construction as an example and established the hazard identification and risk assessment model during the sluice engineering construction period. It had been successfully used in the identification and risk assessment of hazard sources during the construction period of the sluice project of the second phase of Zhaokou Yellow River diversion irrigation area. The research results show that the construction operation risks and building material risks have the greatest impact on the overall safety of the project and the two types of hazard sources that need to be focused on prevention and control during the project construction period. [ABSTRACT FROM AUTHOR]

Combined with special investigation results of special inspection on safe operation and management of sluice in recent years, this paper expounds the safety status of sluices in China and the scrap issue faced after the loss of sluices function. It studied from the aspects of sluices scrapping condition, scrapping approval of sluices standards argument. At the same time, combined with the actual situation in our country, it analyzed the sluice scrap of organization and management, project inspection and acceptance of engineering and non-engineering measures and scrap disposal procedures, Finally, aiming at the present sluices scrapped work situation, it proposed corresponding countermeasures and suggestions. [ABSTRACT FROM AUTHOR]

Large irrigation areas have various building forms, complex geological environment and difficult construction, so risk accidents are prone to occur during engineering construction. Taking Zhaokou Yellow River irrigation area phase Ⅱ project as an example, the paper introduced the theory and technology of grid management into the safety management of the construction. According to the ideas of grid management, the management objects were divided into grid units, and a grid service team was formed to establish a safety management information platform that was suitable for its management model with the help of information technology to form a horizontal and vertical, collaborative and orderly accurate grid safety management model. It analyzed the advantages of the grid safety management model and its operating mechanism, and proposed that the system management model of Zhaokou Yellow River irrigation area phase Ⅱ project through the grid safety management model can be used to improve the efficiency of risk treatment of the irrigation area. [ABSTRACT FROM AUTHOR]

In order to study the adaptability of short duration rainstorm frequency distribution curve under different sample selection methods, in this paper, 11 short-duration rainstorm sequences of 39 meteorological stations in the Weihe River basin of Shaanxi Province were taken as the research object, parameters were estimated by L-moment method. Root mean square error test was used as the goodness of fit evaluation method. From the two aspects of optimal distribution of rainstorm sequences with different durations at the same station and optimal distribution of rainstorm sequences with different stations at the same duration, the adaptability of 13 frequency distribution curves under 3 sampling methods of annual maximum method, annual multiple sample method and annual super large value method were analyzed and compared. The results show that the Generalized Pareto distribution (GEP) has good adaptability to the 3 sampling methods, which can be used as the theoretical frequency analysis of short-duration rainstorm in this research area. [ABSTRACT FROM AUTHOR]

In order to avoid the influence of subjective factors on the results of extracting typical rainfall years, based on the rainfall data of Lanzhou City in 29 years, this paper selected 5 similar factors of annual rainfall, annual rainfall days, flood season rainfall, dry season rainfall and extremely poor annual rainfall days, and used the euclidean distance fuzzy similarity priority ratio method to extract typical rainfall years. Taking the control rate of total annual runoff and cumulative rainfall frequency as the evaluation index and combining with correlation analysis, it evaluated the extraction results. At the same time, the above extraction results were compared with the calculation results of absolute distance fuzzy similarity priority ratio method to verify the accuracy of euclidean distance fuzzy similarity priority ratio method and the simplicity of the calculation process. The results show that 1991 is a typical year of rainfall in Lanzhou City, the curve’s correlation coefficients between the total annual runoff control rate and cumulative rainfall frequency in typical rainfall year and the annual total runoff control rate and cumulative rainfall frequency for many years are 0.997 and 0.981 respectively. The extracted results are reliable, which not only reflect the typical rainfall characteristics of Lanzhou, but also meet the needs of sponge city construction. Compared with the absolute distance fuzzy similarity priority ratio method, the euclidean distance fuzzy similarity priority ratio method simplifies the calculation process. [ABSTRACT FROM AUTHOR]

In order to encourage the in-depth implementation of China major national strategies on ecological protection and high-quality development of the Yellow River Basin, this paper based on the theoretical significance of Economic Geography, the Thought on Ecological Civilization, Dual-Nuclei Structure and the practical needs included the service and integration into the new development pattern, the coordinated development of the north-south economy and the high-quality development in inter-provincial border areas, a strategic concept of Zhengzhou and Jinan Twin City Economic Circle was put forward. The feasibility of Zhengzhou and Jinan Twin City Economic Circle construction was analyzed empirically through the strength of economic connections between Zhengzhou and Jinan, and the spatial layout of “One District, Two Cores and Three Belts” was constructed. Policy recommendations to promote the construction and development of Zhengzhou and Jinan Twin City Economic Circle were put forward by accessing the five aspects of strengthening the development of adjacent areas between Henan and Shandong; ensuring the security and ecological co-governance of the Yellow River Basin; consolidating the construction of transportation infrastructure; strengthening scientific and technological innovations and industrial co-operations; and deepening the integrated development of culture and tourism. [ABSTRACT FROM AUTHOR]

The installation of composite insulation material in canals will reduce the frost heave force of foundation soil and the displacement caused by uneven frost heave of canal slope plate. However, the research on the anti-freezing mechanism of composite insulation material in canals has not been proved. In this paper, the application of polymer material under the canal lining structure of Xinjiang Manas Power Station was taken as the actual engineering background. Considering the interaction between composite materials and the interaction between frozen soil and composite materials, the frost swelling model of concrete lining insulation structure in cold area was established according to the canal thermodynamic coupling mechanism, and three new composite insulation forms were proposed and analyzed by COMSOL Multiphysics5.2 a. The results show that compared with the conventional canal, the three thermal insulation methods have certain thermal insulation effect, and the third one has the most obvious frost resistance and thermal insulation effect. Under the action of this form, the maximum normal displacement of shady slope, sunny slope and base-plate is 9.63 cm, 4.74 cm and 1.87 cm respectively and compared with the prototype canal, the frost heaving force of form 1, form 2 and form 3 is reduced 65.8%, 76.2% and 89.5% respectively. [ABSTRACT FROM AUTHOR]

Aiming at the tunneling performance of double shield TBM under complex geological conditions, based on double shield TBM construction at water conveyance tunnel in Lanzhou water source construction engineering, this paper studied the equipment utilization ratio, disc cutter consumption and tunneling speed of TBM under different geological conditions by the method of statistical analysis of field measured data. The results show that. a) for class Ⅱ, Ⅲ and IV surrounding rocks, the TBM utilization rate increases with the decrease of surrounding rock types, but the TBM utilization rate of class Ⅴ surrounding rocks is generally lower than 10% because of water gash and TBM block accidents. b) The TBM disc cutter consumption of hard rock is significantly higher than that of soft rock. Hard rock with the decrease of surrounding rock classification, the disc cutter consumption is obviously reduced. c) For the surrounding rocks of Class Ⅱ, Ⅲ and Ⅳ and Ⅴ, with the decrease of the class of surrounding rocks, the penetrate rate increases obviously. The advance rate of TBM is affected by the penetrate rate and the utilization ratio of equipment. The average tunneling speed of Class Ⅱ, Ⅲ and Ⅳ surrounding rocks increases with the decrease of the surrounding rock class. However, the surrounding rock of class Ⅴ is affected by the low utilization rate of equipment, and its average tunneling speed is the lowest. [ABSTRACT FROM AUTHOR]

The ecological compensation standard for water in inter-basin water transfer should not only truly reflect the value of water resources in inter-basin water transfer, but also consider the economic affordability of the public in the water-receiving area. Taking Beijing, the water-receiving area of the Middle Route of the South-to-North Water Diversion Project as an example, the paper studied its ecological compensation standard, selected water supply, water resources regulation and storage and net primary productivity as the evaluation indicators of ecosystem service value, energy analysis theory was used to calculate the energy/monetary value of each index, and the the incremental value of the service value of the ecosystem in Beijing from the water supply of the South-to-North Water Diversion Project was comprehensively obtained. Conditional value assessment method was used to investigate the population between 20 and 70 years old people in Beijing who had lived continuously for more than half a year to determine the public’s willingness to pay. The results show that the increment of ecosystem service value of Beijing is 3.898 billion Yuan, the public’s willingness to pay is 915 million Yuan, and the willingness to pay is much lower than the increment of ecosystem service value. Based on this, the water resources ecological compensation standard of Beijing South-to-North Water Transfer Project is proposed, the Beijing’s ecosystem service value increment is the upper limit of the ecological compensation standard, and the public’s willingness to pay is the lower limit of the ecological compensation standard. The diversified ecological compensation mechanism provides scientific basis and promotes the sustainable and healthy development of social economy. [ABSTRACT FROM AUTHOR]

he long-term conversion of farmland to forests has improved the ecological environment of the Yellow River Basin, and rapid urbanization has also led to serious habitat degradation. This paper integrated the ecosystem service function model （InVEST）, local spatial autocorrelation analysis （Local Moran’s I） and geographic detector （Geodetector） to explore the temporal and spatial evolution of habitat quality and its driving factors in 19 counties along the Yellow River in Shanxi Province from 2000 to 2020. The results show that a) from 2000 to 2020, the habitat quality index of 19 counties along the Yellow River in Shanxi Province is increased from 0.526 to 0.539, forming a spatial distribution pattern with low altitude and high altitude. The overall habitat quality in the north has been improved; the habitat degradation degree shows a spatial pattern of weak in the south and strong in the north, and habitat degradation in the middle and low altitude areas is increased with time. b) Local spatial autocorrelation analysis shows that both habitat quality and habitat degradation degree are LL-type agglomeration in the southern plains, and complementary in the northern HH-type agglomeration. c)Geographical detection analysis finds out that NDVI and terrain （elevation, slope） are the dominant factors affecting the habitat quality of the 19 counties along the Yellow River in Shanxi Province; NDVI and the interaction of slope are the largest in 2000 and 2010, and the interaction between NDVI and annual average temperature is the largest in 2020; the socioeconomic factors （population per unit area, GDP） and NDVI also have a strong synergistic effect. [ABSTRACT FROM AUTHOR]

In view of the serious impact of coal mining on karst water resources, this paper took a coal mine of Xishan in Taiyuan as an example and adopted the characteristic analysis method of sulfur, strontium and hydrogen and oxygen isotopes to study the main sources of isotopes in karst groundwater, calculate the mine drainage and the mixing ratio of karst water in the fissure water in the mining area and quantitatively evaluate the impact on karst groundwater. The results show that in the coal mine in Xishan, the proportion of karst water（including surface water） in the mine drainage is 51%, and the proportion of karst water（including surface water） in the fissure water is 60%, and the amount of karst water affected by coal mining is calculated as 1.295 million m³/a. [ABSTRACT FROM AUTHOR]

In order to help solve the water resources issues that restrict the high-quality development of the Yellow River Basin, based on the multi-regional input-output table of China, this paper calculated the virtual water of the nine provinces in the Yellow River Basin from 2012 to 2015 by building a multi-regional input-output（MRIO） model, and analyzed its flow pattern and trend. The results show that a)the Yellow River Basin changes from virtual net water outflow area to inflow area between 2012 and 2015. The upstream area is always the virtual water outflow area, the downstream area is always the virtual water inflow area, and the midstream area is transformed from the virtual water inflow area to outflow area. The flow pattern of virtual water is not coordinated with water resources. b)Virtual water flow sectors have great industry similarities. However, there are differences in the trade structure of virtual water in different regions. c)In the virtual water trade within the Yellow River Basin, Shaanxi, Shanxi and Henan are the main virtual water consumers, while Qinghai and Ningxia are the main virtual water suppliers. The virtual water flowing out of the Yellow River Basin mainly flows to the northeast and Beijing-Tianjin-Hebei region. Finally, the suggestions are proposed to promote the optimization and allocation of water resources and help the high-quality and coordinated development in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

In order to deal with the imbalance of water resources in the water receiving area of the Yellow River Diversion Project in Henan Province and provide a reference for the rational allocation of water resources in the water received area, this paper used Lorentz Curve to calculate the Gini coefficient of 14 prefecture level cities in the water received area, and used the method of connection number calculation combined with the subtractive set pair potential to diagnose and discriminate the unbalanced sub areas. The results show that from 2010 to 2020, the matching of water resources with population and cultivated land area in the Yellow River diversion and received area is in a relatively balanced or balanced level, and the overall water resources spatial equilibrium level is in a relatively balanced or balanced level for a long time; the severe situation of the spatial balance grade of water resources and population shows that Zhengzhou radiates to the surrounding areas, and the spatial balance grade of water resources and cultivated land area shows that the north of Henan Province is worse than that of the south; in 2020, the vulnerable areas of water resources spatial balance include Zhengzhou, Puyang, Xinxiang and Anyang, which are the main control objects of water resources balanced distribution. [ABSTRACT FROM AUTHOR]

In view of the increasing prominent water resources shortage in China, in order to further improve the efficiency of water resources utilization, this paper was based on the maximum interest of farmer households and the individual interests of all farmers from the perspective of cooperative game theory and non-cooperative game theory. Taking the fixed total water consumption and food security of farmer households participating in water rights transaction as constraints, the marginal benefit method and Lagrange multiplier method were used to find the optimal solution and a pricing model of water rights transaction price based on game theory and water production function was built. It applied the model to the farmer households’ water rights trading in Yangtang canal irrigated area of Hetao irrigation region in Inner Mongolia and calculated the changes of transaction water volume, water price and interest of each scheme from different game perspectives. In the perspective of cooperative game theory, all farmer households participated in water rights transaction, the value-added of collective interests was 162 400 Yuan reaching to the maximum, the total transaction water volume was 36 460 m3, and the transaction price was 2.205 Yuan/m³; In the perspective of non-cooperative game theory, it would form a Nash equilibrium in which both farmer N1 and farmer N3 trade water rights with farmer N2, at the moment, the value-added of collective interests was 140 700 Yuan, the total transaction water volume was 24 632 m³ and the transaction price was 2.208 Yuan/m³, comparing with non-cooperative game, cooperative game could ensure fairness and further optimize the allocation of water resources. [ABSTRACT FROM AUTHOR]

The paper analyzed the characteristics of ice-run regime in ice-run period in Ningxia-Inner Mongolia reach of the Yellow River from 2018 to 2019, which came to a conclusion as follows: the first ice-run appearance was late but the speed of freezing-up was fast, large of interval inflow and discharge when the river was frozen up; smaller water storage and uniform released, lower water stage of freezing-up which was opposite to that when the river was completely frozen and the flow capacity under the ice was well, small ice-run flood and water amount, little drift ice of the breaking up and ice-run regime in ice-run period was smooth and steady. The main influencing factors included temperature, upper catchment inflow, reservoir regulation, artificial ice run diversion and channel boundary condition. [ABSTRACT FROM AUTHOR]

With the global warming and the acceleration of urbanization in China, the original balance among the rainfall characteristics, the underlying surface conditions and the disaster prevention and reduction capacity in cities has been broken, as a result, the degree of waterlogging in the city is getting worse and the hydrological law is changing constantly. Therefore, the importance of urban hydrological analysis is becoming more and more obvious. In this paper, four sub-models of urban hydrodynamics were proposed, which were the Urban Hydrologic Response Unit sub-model based on GIS, urban runoff sub-model, confluence sub-model and drainage sub-model based on SWMM. In this model, Xining was taken as an example to simulate. Based on the simulation results of heavy rain in different recurrence periods, the hydrological laws were analyzed systematically. The results show that the total amount of nodal overflow under two-year and five-year simulation accounts for 34.2% and 38.3% of the total runoff, the full load of the Xining pipeline is mainly caused by the jacking of the downstream pipeline, and the drainage capacity of 36.1% of the drainage area is poor. [ABSTRACT FROM AUTHOR]

In order to provide reference for the implementation of ecological protection and high-quality development strategy in the Yellow River Basin, taking the nine provinces（regions） in the Yellow River Basin as the research object and high-quality development as the starting point, from the perspective of promoting high-quality development, this paper used three-stage DEA model, Malmquist DEA model and absolute β convergence test model to calculate the green economic efficiency of the Yellow River Basin and analyzed the convergence based on the spatial panel data from 2009 to 2017. The results shows that the overall efficiency of green economy in the Yellow River Basin is low, and there are obvious differences in the efficiency of green economy in all provinces and regions; ignoring the influence of external environmental factors and random interference, it will overestimate the efficiency of green economy in the Yellow River Basin; the external environmental factors affecting the efficiency of green economy in the Yellow River Basin are diverse and complex, and the improvement of per capita GDP and urbanization rate is helpless for improving the efficiency of green economy, the proportion of general budget expenditure in GDP is conducive to improve the efficiency of green economy, and the proportion of fixed assets investment in agriculture, forestry, animal husbandry, fishery and mining industry will help to improve the efficiency of green economy; caused by the decline of technological progress change index, the overall green economic efficiency of the Yellow River Basin is declining; the green economic efficiency of the Yellow River Basin has the trend of convergence, which is reflected in the convergence of pure technical efficiency and scale efficiency. [ABSTRACT FROM AUTHOR]

BIM (Building Information Modelling) technology helps design firms to improve design pattern, product value and market competitiveness. However, it has not been used in most design firm. In order to offer the guidance for latecomer firms during the transformation of design pattern, this paper divided the period of BIM application into Entrance Period, Expanding Period and Popularized Period based on paper and technology, value and cooperation factors, then coming up with design pattern evolving path based on BIM technology during each period. In the end, discussing and verifying the specific process of design pattern evolving by the case of Hohhot Rail Transit Project. To conclude, the evolving path has overturned the traditional design pattern to some extent and extended to the whole hydropower design firm. It has promoted the digitization and informatization of the design firm. [ABSTRACT FROM AUTHOR]

In order to realize the unified allocation of mine water into water resources, starting from the spatial utilization pattern of mine water, on the basis of clarifying the classification of mine water utilization and considering the requirements of two-way coordination between supply and demand, this paper analyzed and proposed the index factors of mine water classified utilization. It constructed the classification index system and evaluation model of coal mine water safe utilization mode by using self-organizing feature mapping network ( SOM) method. Taking a typical coal mine in Ningdong coal base as an example, this paper evaluated the classification of mine water development and utilization pattern. The results show that the evaluation index system of utilization pattern classification constructed can effectively identify the key items of main categories. [ABSTRACT FROM AUTHOR]

During long distance water delivery project of pumping station, water hammer protection scheme of conventional pump is usually based on the pumping accident to set up the water hammer protection measures, the influence of buried pipe burst to the transition process of water delivery system is seldom considered. When a point in the downstream pipeline occurs pipe burst, severe water hammer drop can induce secondary or serial pipe burst accident. In this paper, the physical process of buried pipe burst in practical engineering was analyzed and a reasonable mathematical model was established based on the working principle of the overflow stable pressure tower. The pumping accident and the pipe burst accident were considered in the design of water hammer protection scheme and a protection scheme combining the air tank and the air valve after the pump was put forward. Combined with a practical water delivery project, this paper compared the influence of different protection schemes to the protection effect of water hammer in the case of pump stopping and pipe burst. The results show that the conventional water hammer protection scheme can effectively eliminate the harm of pump stopping accident, the combined protection scheme of air tank and air valve can effectively prevent the transmission of the pressure drop wave of the water hammer in the pipe burst accident and avoid the occurrence of the second pipe burst accident. [ABSTRACT FROM AUTHOR]

This paper studied the coordination degree between water environment and social economy in the Yellow River basin from multiple logical and spatial dimensions. Based on the analysis of the interaction between water environment and social economy, the water environment index system of the Yellow River basin was constructed from three logical dimensions of water resources, water pollution and water governance. The coupling coordination model was used to measure the overall coordination degree between water environment and social economy in the Yellow River basin. From the three spatial dimensions of the upper, middle and lower reaches of the Yellow River basin, seven urban agglomerations along the Yellow River and 61 cities, and three logical dimensions of water resources, water pollution and water governance, this paper used Deng’s correlation degree method to measure the correlation level between water environment and social economy and explore its causes. The results show that the overall coordination degree between water environment and social economy in the Yellow River basin is low but increasing. From 2009 to 2018, the correlation degree between the three logical dimensions of water environment and social economy fluctuated between 0.7-0.8 and the spatial differentiation is not obvious. From 2009 to 2018, the correlation degree between water environment and social economy in the middle of the Yellow River basin has been increased, while the correlation degree between water environment and social economy in the upper and lower reaches of the Yellow River basin has been decreased. Taiyuan urban agglomeration shows an increasing trend and Ningxia urban agglomeration along the Yellow River decreases slightly. Among the 61 cities, it needs to focus on the cities of Longnan, Linfen and Baoji that have high correlation between water resources and social economy, the cities of Guyuan, Jincheng and Longnan that have high correlation between water pollution and social economy and the cities of Linfen, Qingyang and Bayannur that have low correlation between water management and social economy. [ABSTRACT FROM AUTHOR]

In order to improve the quality of ecological environment protection, wireless sensor network (WSN) is widely used in the ecol cal environment intelligent monitoring in the Yellow River Basin. The energy consumption and lifespan of sensor nodes are the key iss faced in wireless sensor network routing. In order to reduce the energy consumption of nodes in the routing process and prevent nodes from ing prematurely, the evolutionary algorithm was applied to WSN routing optimization. This paper improved the traditional optimization alg rithm and applied the improved adaptive evolution algorithm to routing optimization, and randomly selected 100-node WSN topology model verify the effectiveness of the algorithm. The results show that compared with the traditional evolutionary algorithm and ant colony algorithm the algorithm in this paper effectively reduces the energy consumption of sensors in the routing optimization of wireless sensor networks, in proves the algorithm convergence speed, prolongs the life of WSN, enhances the connection reliability and realizes real-time monitoring an protection of ecological environment in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

The irrigation area is the key technology for the precision irrigation and charging of the irrigation area. Based on the momentum theorem, this paper designed a new type of device for measuring water flow in open channel. This paper explored the difference of hydraulic properties among different shape flats, and looked for the optimal geometric shape of flat. Using statics analysis on flats in narrow and deep rectangular open channel uniform flow, we found that the relationship between quantity of flume and opening angle of testing flat had a single value corresponding. Combined with experiment outcome in laboratory, for different geometries and shrinkage ratios flats we extrapolated the half theoretical and half empirical formula of flow and range of application. Compared experiment results of designed testing flat, such as, flow range, the measurement error, head loss and flow stability, we concluded that T-shape flat with shrinkage ratio of 0.5 to 0.6 was recom mended. [ABSTRACT FROM AUTHOR]

In order to impound and reinforce warping dams, hascx-l on the fluid solid coupling theory ;md strength reduction method, this paper analyzed the seepage and stability of Hejiazhuang warping dam during its impoundment operation hy using ABAQUS finite clement software, put forward the ideas of seepage prevention and reconstruction such as day inclined wall m1d geomemlmme and calculated and analyzed the stability m1d seepage characteristics of each reconstruction scheme. The results show that : the numerical simulation method used in this paper is foasihle compared with traditional methods ; as a water and soil conservation measure, Hejiazhuang main warping dam did not consider long-term water storage in the original design. If the water storage is normal according to the design standard, its stability docs not meet the requirements, so it needs to he reinforced and reconstructed, and it is difficult to achieve the expected dfcx·t only by using the way of upstream dam slope slowing down ; both the gcomembrane reconstruction scheme and the day inclined wall 1u·onstruction scheme can improve the safety c

The optimization of the industrial layout in the Yellow River Basin is of considerable significance to promote its high-quality development. Based on investigating the basic situation of the industrial layout of the nine provinces (autonomous regions) in the Yellow River Ba sin, this paper depicted the distribution map of key industries in the Yellow River Basin and analyzed the current situation of the industrial layout in the Yellow River Basin and its impact on the Yellow River. This paper also discussed the applicability of three industrial layout models, including the growth pole development, point-axis development and network development under the condition of high quality development in the Yellow River Basin. The industrial layout optimization matching the high-quality development of the upper, middle and lower reaches of the Yellow River was proposed and the expected effect of this optimization's implementation was also studied. The results show that the effective industrial layout models matching high-quality development of the Yellow River Basin are expanding the industrial circle radiation range of existing growth poles and developing new growth poles, strengthening the driving ability to exist industrial axes and developing new shafts, as well as carrying out green and sustainable industrial development. [ABSTRACT FROM AUTHOR]

In order to analyze the change regulation of regional drought and flood, based on the standard precipitation evapotranspiration index (SPEI) that can effectively evaluate the drought and flood degree quantitatively, the frequency of drought and flood was studied by using in-formation diffusion technology which was good at small sample data analysis, and the chaotic time series prediction model based on information diffusion adding-weight one-rank local-region method was proposed to analyze the trend of drought and flood time series. Taking Xi' an as a typical region and September as the research period, the method suggested in this paper was used for analysis, according to the temperature and precipitation data from 1951 to 2015. The results show that a) the probability of moderate drought or above is about 19.5%, while the probability of moderate wet or above is about 17.5%. b) During 1951-1962, the trend is drought. During 1963-1986, there is a trend of wet. From 1987 to 2002, there is a trend of drought. After 2003, the trend of wet appears again. c) The maximum Lyapunov exponent of drought and flood series is 0.149 2, which shows that the time series of drought and wet have chaotic characteristics. The new chaotic prediction model is used to predict the trend of drought and flood from 1985 to 2002, which is in good agreement with the actual situation and verifies the effectiveness of the method. [ABSTRACT FROM AUTHOR]

During the operation of water control project, the scour funnel will be formed in front of the dam when the water release structure releases water. The shape, size and vertical and horizontal slope of the funnel are of great significance for the clearance of the front of the orifice gate of the dam power station. In this paper, a model test study on the funnel shape in front of a dam of a reservoir in the Yellow River was carried out, and the funnel shape, vertical and horizontal slope changes and characteristics of sediment discharge bottom outlet under two different operation modes of scouring and silting were summarized, so as to put forward the most reasonable operation scheme for effectively preventing the silt blocking in front of the sediment discharge inlet and realizing the cleaning in front of the power generation intake gate. Comparing with other existing test results, it shows that the test results are reasonable and reliable. Considering the balance of scour and siltation in front of the dam and the normal operation of desilting tunnel, the shape and scope of the scour funnel in front of the dam formed by the model test are conservative and the slope of the funnel is steeper than that of the prototype observation value. [ABSTRACT FROM AUTHOR]

This paper reviewed the theories and results of sponge city/airport construction at home and abroad, discussed the principles and objectives of sponge airport construction. According to the actual situation of different regions, low-impact development ( LID) facilities suitable for airports in different regions were designed. Finally, an airport was taken as an example to verify the rainwater control effect of LID based on SWMM model. The research shows that after the construction of LID, the reduction rates of total runoff and peak flow are up to 74.0% and 51.0%, and the peak time is delayed by up to 16 minutes. After LID are added in the flight area, the number of overflow nodes decreases by 13.1%, and the number of overloaded pipe segments decreases by 20.4%. After the addition of LID in the parking lot, the number of overflow nodes is reduced by 6.3%, and the number of overloaded pipe segments is reduced by 10.0%. The maximum water depth of the pipe section changes by 68% at most and the maximum flow by 63% at most. The planning and construction of LID in airports has a significant effect on the control of rain runoff and peak flow, which not only reduces the drainage pressure of the airport rainwater pipe network system, but also plays an important role in the flood control and drainage of airports. [ABSTRACT FROM AUTHOR]

It is worth noting that the impacts of Xiaolangdi Project construction and operation on the ecological service value of its upstream and downstream riparian zones. Therefore, this paper divided the upstream and downstream riparian zones affected by the Xiaolangdi Project into different sections, and utilized the equivalent factor method to assess the changes of different sections' riparian ecosystem service values during the project' s construction and operation period. The results show that it appears a decreasing trend in the land use area of the riparian farmland and grassland ecosystem during the project' s construction period; the project has caused a positive impact on the ecosystem service value during the early operation period, and the greatest impacts are found in Liaocheng-Binzhou section; during the later operation period, the positive impacts are weakened, while the negative impacts are enhanced when human activities along the superposition are added, among which the estuary area is suffered the most. [ABSTRACT FROM AUTHOR]

Based on the method of determining the drought limit water volume of reservoirs by stages, this paper polymerized the cascade reservoirs and proposed a method of determining the drought limit water volume of polymerized reservoir. Taking Fenhe Reservoir and Fenhe II Reservoir as the research object, the two reservoirs were generalized into polymerized reservoir and the drought limit water volume of polymerized reservoir was determined by inverse recursive method. The drought warning water volume of polymerized reservoir in dry season and agricultural irrigation period is 299.37 million m³ and 239.45 million m³, and the drought guaranteed water volume is 189.82 m³ and 135.01 million m³. After setting drought limit water volume, the number of water shortage months for life, ecology and industry in typical drought years, from June 1965 to May 1966, is decreased from 3, 5 and 5 to 0, 1 and 1, individually 1 month. The water shortage in agriculture increases to 6.41 million m³, but the water shortage of life, industry and ecology decreases to 27.17 million m³. It can be seen that the formulation of drought limit water volume has played a regulatory role in the cross drought year. From the perspective of the overall water supply interests of various industries, the losses suffered by agriculture are still within an acceptable range and the increase of water shortage is small. After setting drought limit water volume, the water supply of life and industry in dry years can be significantly improved by slightly reducing agricultural water supply. [ABSTRACT FROM AUTHOR]

Bikou Reservoir is an important water conservancy project of flood control in Bailong River Basin, but limited by the conventional flood control operation mode, the regulation role of flood control storage capacity cannot be brought into full play. In view of this, based on the dynamic programming algorithm, this paper carried out the research on the optimal flood control operation of Bikou Reservoir and established the minimum model of reservoir discharge based on the goal of maximum peak shaving criterion. At the same time, in order to solve the issue of "small discretization for low precision and large discretization for long calculation time" in the solution of dynamic programming, a new solution method based on non-uniform discrete dynamic programming was proposed. The results of two typical design flood processes show that the optimal flood control operation can give full play to the regulation role of limited flood storage capacity, so that the peak clipping rate of 20-year flood can reach 50.4%, and that of 5,000-year flood can reach 38.9%, which not only has remarkable peak clipping effect, but also the discharge process of the reservoir is more gentle than that the conventional flood control operation mode. [ABSTRACT FROM AUTHOR]

The ice-cover in a river will obviously change the flow structure. This paper established the vertical 2-D numerical model with k-ε turbulence model for ice-covered flow, simulated the velocity distribution in a freeze-up river and analyzed the main factors influencing the velocity distribution patterns. The calculated result shows that the velocity distribution in a freeze-up river mainly related to bed roughness nb, ice roughness nb and flow conditions, under the same flow conditions, the ni/nb, is smaller and the Umax. is closer to the ice-cover. In the flow core the distribution of velocity deviates from the logarithmic law and the velocity gradient of Umax is almost zero. [ABSTRACT FROM AUTHOR]

During the autumn flood season of 2021, rainstorms occurred frequently in the main and tributaries of the Yellow River, and three numbered floods followed, with rare flood history. This paper summarized the characteristics of this autumn flood from the aspects of rainfall, water, flood and reservoir operation and lists historical autumn floods for comparison. Around the three numbered floods of the Yellow River, through the changes of inflow and outflow and water level of Sanmenxia, Xiaolangdi, Luhun, Guxian and Hekoucun reservoirs in the regulating process, it was calculated that the peak clipping of the "five-reservoir joint regulation" in the three floods was 49.29%, 46.10% and 47.84% respectively. The flood detention effect was Xiaolangdi > Sanmenxia > Guxian > Luhun > Hekoucun. Through the analysis, it is concluded that the local river flat flow in the lower reaches of the Yellow River is less than 5,000 m³/s, which is the most critical factor restricting reservoir operation and downstream flood control safety. Suggestions are put forward to improve the flood capacity of the lower reaches of the river at the bayou section so as to open the operation space of cascade reservoirs. [ABSTRACT FROM AUTHOR]

The large-scale construction of warping dams and other soil and water conservation projects on the Loess Plateau is the fundamental strategy to eradicate the flood in the lower reaches of the Yellow River. Based on the analysis of the mechanism of silt trap and erosion re-duction, this paper believed that silt trap could raise the erosion base level and enhance the regulation and stability of water and sediment in the slope and gully system, thus becoming the most significant engineering measure to trap and reduce sediment entering into the Yellow River. After analyzing a series of problems of high risk of traditional warping dam collapse, it recognized that only innovating and improving the engineering structure of warping dam is the only way to eradicate the Yellow River. Tsinghua University and the China Academy of Water Re-sources and Hydropower jointly explored and developed the new technology of steel-concrete precast tubular sheet pile combination method to build and reinforce silt traps. By using the cooperative pressure bearing structure of steel-concrete precast sheet pile, tubular pile and retaining body, a "hybrid structure system" was formed, and a "tubular sheet pile combined warping dam" was built. It is a brand-new clam engineering technology. Sheet pile dam or tubular sheet pile dam is the core of the engineering pressure bearing system. It avoids the instability of earth dams caused by seepage damage, and is also conducive to improving the quality and efficiency of dangerous and old check dams, ensuring the safety of the project and continuous sediment detention. In addition, the drainage structure and spillway composed of steel-concrete sheet piles overcome the corresponding defects of traditional projects. Finally, through the design examples of typical warping dam construction and danger removal and reinforcement, the key points of the implementation of the new technology are explained, which fully reflects the advantages of the new technology of warping dam, such as deep foundation, strong flood control capacity, fast construction progress, expansion of sediment detention and flood detention capacity, low cost, low management and protection pressure, and can also significantly reduce the occupation of large areas of sloping farmland or forest and grassland by the dam construction and have little impact on the ecological environment. [ABSTRACT FROM AUTHOR]

The Grain for Green Project (GGP), which was implemented in China since 1999, has achieved remarkable achievements, but some new issues have gradually emerged, and it is necessary to carry out scientific evaluation and systematic sorting. In order to provide scientific basis for the ecological construction and high-quality development of the Loess Plateau in the new period, this paper comprehensively evaluated and analyzed the achievements and problems of afforestation and grassland construction in Yan' an City after the implementation of GGP, and put forward specific countermeasures and suggestions based on the field investigation and remote sensing image interpretation of typical years from 1990 to 2020. The achievements obtained by the implementation of GGP in Yan' an City are as follows: ecological quality has been improved obviously, land use structure has been adjusted rapidly, agricultural industrial structure has been adjusted, fanners have been lifted out of poverty and become rich, forest and grassland area has been rapidly enlarged and vegetation recovered well. The problems in vegetation construction that Yan' an City currently faced are: vegetation restoration on a large scale has changed surface hydrological processes ( limited precipitation is expended through evapotranspiration, and is not conducive to subsequent stable growth of established vegetation and the ecological service function of continuous play), forest types are single during afforestation, artificial grassland construction scale has limitations, and large area of natural grassland needs to be reasonably explored. Suggestions for vegetation construction in Yan' an City in the future: to carry out comprehensive evaluation and planning of regional agriculture, to strengthen ecological effect monitoring and evaluation of GGP, to optimize forest stand and tree species step by step, to strengthen tending management and rational utilization of natural grassland, and to support and build animal husbandry sustainable development system. [ABSTRACT FROM AUTHOR]

Scientific and technological innovation is the fundamental support for ecological protection and high-quality development in the Yellow River Basin. This paper analyzed the current status of scientific and technological innovation in nine provinces ( autonomous regions) in the Yellow River Basin from 2016 to 2020, and finds that the supporting mechanisms of scientific and technological innovation for ecological protection and high-quality development in the Yellow River Basin are as follows: speed up the digitalization process of factors of production, smooth the high-quality factor circulation mechanism, improve the adaptability and innovation level of the economic structure, build high-quality synergy mechanism, optimize the law-based business environment, and implement the digitalization progressive governance mechanism. The Yellow River Basin ecological protection and high quality development of science and technology innovation support mechanism path and policy Suggestions for: in green technology innovation as the gripper coordinated development, promote the global ecological construction of the Yellow River Basin integrated large data center, improve the efficiency of digital integration of government affairs, increase efficiency and improve the business environment under the rule of law governance service governance and supervision system, etc. [ABSTRACT FROM AUTHOR]

Aiming at the issue that the existing water distribution plan in irrigation area can not meet the actual operation of canal system and the real-time water demand of crop growth and development, a real-time optimal water distribution model of canal system based on crop water demand process was established. Taking the ending time of lower level canal water distribution as the decision variable, and taking the objective function as the minimum sum of water shortage rate and the minimum water loss of canal system, the paper used the genetic algorithm to solve the model. The results show that: compared with the water distribution scheme prepared by the empirical method, the water distribution time of all levels of canal system is more reasonable, and the fluctuation of water distribution flow is small; the irrigation allocation is more in line with the actual water demand of crops, and the coupling degree with the real-time water demand of crops is higher, the water shortage rate of irrigation area is reduced by 13.6%, the water distribution time is reduced by 2.5 days, and the water transfer loss of canal system is reduced by 6.3%. The canal water distribution achieves the time-saving, efficient and water-saving goals. [ABSTRACT FROM AUTHOR]

As the Ecological Protection and High-Quality Development of the Yellow River Basin has become a national strategy, the resources attributes and value of the Yellow River sediment have become increasingly prominent. This paper discussed the feasibility of using the Yellow River silt in Kaifeng section as concrete fine aggregate. Through experiments, 12 sets of concrete mixing ratios were designed, and the mixing ratio of the Yellow River silt and machine-made sand was studied, and the fly ash cement replacement rate affected the performance of concrete and the influence of mechanical properties. The compatibility of the Yellow River sediment and fly ash was analyzed under the selected maximum replacement ratio of the Yellow River sediment. The test results show that the compressive strength of the 28 days concrete test block is 5% higher than that of ordinary concrete when the ratio of the Yellow River sediment to the machine-made sand is 10%; the optimal replacement re-do of the Yellow River sediment is 20%, the concrete strength can reach 41.3 MPa, the slump is 190 mm, and the expansion degree is 480 mm. Compared with ordinary concrete, the performance is basically the same; under the working condition that the maximum replacement ratio of the Yellow River sediment is 30%, the compatibility of the Yellow River sediment and pulverized coal ash in concrete is good. [ABSTRACT FROM AUTHOR]

There are nearly 400 development zones above the provincial level in the Yellow River Basin. The rapid expansion of development zones not only drives local economic growth, but also causes problems such as prominent contradiction between land supply and demand, low ef-ficiency of spatial resources allocation and environmental pollution. By establishing DPSIR model, this paper analyzed the evolution trend of de-velopment zones in the Yellow River Basin and the distribution characteristics of leading industries from the perspective of ecological carrying capacity. The results show that the agglomeration characteristics of the development zones of the Yellow River Basin are obvious, the quantity and scale are increased obviously, and the overall ecological carrying capacity of the agglomeration areas in the development zones has been de-creased. The development zones are distributed in the east-west direction, with the trajectory and center of gravity of the national development zones shifting eastward, and the provincial development zones shifting southwest from the overall trajectory and center of gravity, increasing the dispersion degree. There are differences in the spatial distribution of different types of industrial development zones. The leading industrial struc-tures of provincial and national development zones are quite different, and the phenomenon of industrial convergence in some provinces is obvious. [ABSTRACT FROM AUTHOR]

Western Henan is a typical arid area of the Yellow River Basin and there is seriously short of water resources. The utilization of ru-ral domestic sewage after treatment can not only improve the utilization rate of water resources, but also reduce the pollution of rural water bodies. This paper introduced the rural domestic sewage treatment system in detail, and studied the influence of two kinds of hydraulic reten-tion time ( HRT) to the system' s removal of nitrogen, phosphorus and COD. The results show that the average removal rate of ammonia nitro-gen varies greatly with different hydraulic retention time, while the removal rate of the remaining indicators differs by less than 1%. When the hydraulic retention time is 24 h, the average removal rates of ammonia nitrogen, total nitrogen, phosphate and COD are 63.09%, 65.41%, 62.83% and 75.31% respectively and the system runs more stably. Therefore, 24 h can be used as the best hydraulic retention time of sewage treatment system. [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 reveal the changing trends and spatial differences of the resources and environmental carrying capacity of the Yellow River Basin, and to provide policy references for the ecological protect • and high-quality development of the Yellow River Basin, this paper selected 20 indicators from the three subsystems of social economy, resources and environment to build a comprehensive evaluation index sys-tem of resources and environment carrying capacity. Based on TOPSIS Model amp combined with obstacle degree diagnosis model, it evaluated the level of resources and environment carrying capacity of nine provinces along the Yellow River Basin from 2008 to 2019 and diagnosed ob-stacle factors. The results show that from 2008 to 2019, the resources and environmental carrying capacity of the Yellow River Basin show a steady upward trend, rising steadily from a low level to a good level; the social and economic carrying capacity and environmental carrying capacity also show a steady upward trend, while the remmrces subsystem has a higher starting point but is fluctuated greater. The reason is that the per capita water resources and other indicators in the resources subsystem fluctuate greatly; the resources and environmental carrying capacity of the provinces ( regions) in the Yellow River Basin vary significantly, among which the resources and environmental carrying ca-pacity of Shandong is close to a good level, and the resources and environmental carrying capacity of Gansu is at a low level. The resources and environmental carrying capacity of other provinces is at the intermediate level; the main obstacle factors affecting the improvement of the resources and environmental carrying capacity of the Yellow River Basin are the amount of domestic waste removal and transportation, the ar-ea of soil erosion control, the proportion of the GDP of the tertiary industry, the consumption expenditure of farmers, the decline rate of unit energy cons lllll pt., the per capita GDP, construct• level of transportation infrastructure, the number of industrial enterprises above desig-nated size and the investment in industrial pollution control. Key Words: [ABSTRACT FROM AUTHOR]

The river regime of some sections in Ningxia section of the Yellow River has not been effectively controlled, and the oscillation of the river regime has led to the slippage and failure of some existing projects and the potential safety hazards of floods and ice-run floods still exist. Taking the Ningxia section of the Yellow River from Xiaheyan to Shizuishan as an object, this paper systematically studied the characteristics of intra-annual and inter-annual variation of water and sediment in the main and tributaries of different river sections and main and tributaries from 1950 to 2019, the evolution process of the river regime, and the distribution of sediment erosion and deposition in the river channel and reservoir, in order to provide scientific support for the preparation of the Ningxia Section of the Yellow River Dredging (Sand Mining) Plan. The results show that a) from November 1950 to October 2019, the average annual water and sediment volumes at Xiaheyan Station in the Ningxia section are 29.86 billion m3 and 113 million tons respectively, and the flood season water and sediment volumes ac-count for 51.7% and 84.1% of the whole year respectively. b) From 1958 to 2019, the annual and inter-annual variation of water and sedi-ment volume at Quanyanshan Station of Qingshui River and Guojiaqiao Station of Kushui River fluctuate greatly, with a great disparity be-tween wet and dry; The multi-year average water and sediment volumes of Quanyanshan Station on the Qingshui River are 114 million m3 and 24.6 million tons respectively, and the multi-year average water and sediment volumes of Guojiaqiao Station on the Kushui River are 97 mil-lion mi and 4.5 million tons respectively. c) After years of slight bend regulation, the river regime of the section from Baxia to Rencundu of Shapotou has tended to be stable; the section from Rencundu to Toudaodun is a transitional reach, and the river regime mostly varies down-ward according to the terrain, and the river regime swing of some reach has been controlled; Toudaodun-Shizuishan reach is a wandering river with wide and shallow riverbed, uncertain mainstream swing and violent river regime change and. d) From May 1993 to November 2018, a total of 215 million tons of sediment has been deposited on the river section from Shapotouba to Shizuishan, of which 37.5 million tons are de-posited on the main channel and 177.5 million tons are deposited on the beach; as of October 2018, Qingtongxia Reservoir has accumulated 559 million m3 of sediment and the storage capacity has been silted up to 92.2%. [ABSTRACT FROM AUTHOR]

In this paper, plastic grass was used to simulate the flexible submerged vegetation in river channel. Through the indoor high-preci-sion flume test, the flow characteristics of the flexible submerged vegetation under different submergence degrees, different vegetation densi-ties and different flow rates were measured and studied with three-dimensional acoustic Doppler velocimeter. The bed roughness, section aver-age velocity and resistance coefficient under the flexible vegetation submergence were obtained. The bed roughness under the vegetation sub-mergence was measured. The relationship among roughness, flow Reynolds number and resistance coefficient was analyzed and the empirical equation of flow resistance of vegetation of vegetation was established through regression calculation of flow resistance coefficient of vegetation. [ABSTRACT FROM AUTHOR]

With the development and utilization of water resources in the western region, 100 m high CFRDs with strong terrain adaptability are becoming more and more common. However, the rheological effect of the rockfill body will cause the slab as the main anti-seepage structure of the rockfill dam to experience voids, compression failure and cracking during the operation period. Experience has shown that setting a pre-settling period before pouring the slab can reduce the problem of slab damage, but the long-term deformation law of the dam and the slab is not clear, which leads to greater arbitrariness in the selection of the pre-settling time. Therefore, considering the safety and economy of the dam, this paper used the finite element method to comprehensively analyze the long-term stress and deformation response of the 100 m high Xujixia CFRD to different pre-settling times. The results show that when the pre-settling time is 180 days, the rheological effect of rockfill during operation can be effectively reduced, and the long-term working behavior of the panel can be improved. The research results have a guiding role for the design, construction and long-term security operation of 100 m high CFRDs. [ABSTRACT FROM AUTHOR]

In this paper, the principle of multi-beam sounding was analyzed and the igh-precision depth data was obtained by using the portable multi-beam sounding system without calibration. The method of characteristic profile was used to three-dimensional terrain analysis. According to the topographic change, the scour condition of the stilling basin was analyzed and judged. The test results show that the accuracy of the sounding is 7.3 cm, which meets the regulation. The portable multi-beam sounding system is highly integrated. It has the characteristics of no calibration, small size and easy installation, which breaks through the limitation of narrow channel space and has demonstration significance for the similar projects. [ABSTRACT FROM AUTHOR]

There are some issues in urban areas, especially in mega-cities, such as low efficiency of intensive utilization, imbalance of ecological space, production space and living space. Taking Zhengzhou City, the capital of Henan Province as an example, this paper discussed the ecological-production-living spaces land use transformation and the temporal and spatial variation generation of environmental effects, based on the four phases of land use data from 1990 to 2019 and on the basis of building the classification system of ecological-production-living spaces. The results show that the area of production and ecological land use has been decreased by 353.33 km² and 186.43 km² respectively, and the area of domestic land use has been increased by 539.76 km². Among the land use types, the largest amount of conversion is agricultural production land use, which is mainly converted to urban and rural living land use. During the study period, the center production land use mainly shifted to southeast. The center of ecological land use is moved not much, and the center of living land use is moved to the east of 3,106 m. The ecological environment quality of Zhengzhou City shows a pattern of “high in the west and low in the east” and is gradually deteriorated from 1990 to 2000. After 2000, it continues to spread in the periphery of the main urban area. The wetlands along the Yellow River and Shuanghe Lake to Yuanboyuan Park are the most improved areas in each period, showing a point distribution. There are two trends of ecological environment in Zhengzhou City: Improvement and deterioration, and the latter is much stronger than that of the former. The transfer of agricultural production land use to urban and rural living land use, water and forest land use to agricultural production land use are the two main factors of deterioration. [ABSTRACT FROM AUTHOR]

This paper analyzed the spatial-temporal variations of vegetation cover at different altitudes and vegetation types over the Qinghai Province and built a long time series NDVI dataset from 1982 to 2018 by using the data of GIMMS NDVI and MODIS NDVI with different spatial-temporal scales. The results show that the overall vegetation cover in the study area has been increased, with the improvement of medium-high altitude and grassland type observed as significant. The vegetation cover in the northwestern and central-eastern area has been increased, while that of the southern region and the Qaidam basin have been decreased from 1982 to 2018, and the temporal and spatial changes of the study area obtained at different scales have good consistency. The increase of vegetation cover in the study area from 1982 to 2018 is significantly correlated with the increase of temperature and rainfall. In addition, vegetation change is significantly correlated with wind speed and sunshine duration in grassland areas above 3000 m. Policies of returning farmland to forest (grass) and returning grazing to grassland have effectively driven the change of vegetation cover in the study area [ABSTRACT FROM AUTHOR]