Urban flood risk assessment under rapid urbanization in Zhengzhou City,China

With accelerated urbanization and climate change,urban flooding is becoming more and more serious.Flood risk assessment is an important task for flood management,so it is crucial to map the spatial and temporal distribution of flood risk.This paper proposed an urban flood risk assessment method that takes into account the influences of hazard,vulnerability,and exposure,by constructing a multi-index urban flood risk assessment framework based on Geographic Information System(GIS).To determine the weight values of urban flood risk index factors,we used the analytic hierarchy process(AHP).Also,we plotted the temporal and spatial distribution maps of flood risk in Zhengzhou City in 2000,2005,2010,2015,and 2020.The analysis results showed that,the proportion of very high and high flood risk zone in Zhengzhou City was 1.362%,5.270%,4.936%,12.151%,and 24.236%in 2000,2005,2010,2015,and 2020,respectively.It is observed that the area of high flood risk zones in Zhengzhou City showed a trend of increasing and expanding,of which Dengfeng City,Xinzheng City,Xinmi City,and Zhongmu County had the fastest growth rate and the most obvious increase.The flood risk of Zhengzhou City has been expanding with the development of urbanization.The method is adapted to Zhengzhou City and will have good adaptability in other research areas,and its risk assessment results can provide a scientific reference for urban flood management personnel.In the future,the accuracy of flood risk assessment can be further improved by promoting the accuracy of basic data and reasonably determining the weight values of index factors.The risk zoning map can better reflect the risk distribution and provide a scientific basis for early warning of flood prevention and drainage.

Evaluation of carbon emissions associated with land use and cover change in Zhengzhou City of China

Studies on carbon emissions associated with land use and cover change(LUCC)are key to understanding the impact of human activities on regional sustainability.In this study,we analyzed the temporal and spatial changes in carbon emissions associated with LUCC for production,living,and ecological spaces in Zhengzhou City of China.Landsat remote sensing images were used to classify the land use and land cover(LULC)types in Zhengzhou City in 1988,2001,2009,and 2015.Carbon emissions associated with LUCC were evaluated using a spatial gradient model and the niche mechanism.It was found that during 1988-2015,carbon emissions associated with LUCC in Zhengzhou City increased by 17.1×10^(6) t,while the carbon sink resulted from cultivated land,forests,water bodies,and unused land decreased significantly.Most of the increase in carbon emissions associated with LUCC occurred in the center of the city.The peak carbon emissions were located in the northeastern,southeastern,northwestern,and southwestern regions of Zhengzhou City,and carbon emissions varied considerably in the different spatial gradient rings over time.Among the three spaces,carbon emissions associated with LUCC were mainly affected by the living space.The population size and population urbanization rate were negatively correlated with the ecological space and positively correlated with the production and living spaces.Our results highlight that Zhengzhou City should take the new urbanization path of urban transformation development and ecological civilization construction to ensure the realization of the promised carbon emission reduction targets.

Identifying the Geography and Determinants of O2O Online Retailers in Megacity in Central China:A Case Study of Zhengzhou City

In recent years,O2O e-commerce,represented by online group-buying,has developed vigorously,which had significant impacts on urban commercial space.Zhengzhou City is a rising national central city in China,and its e-commerce development level is ahead,but relevant researches are rare.Therefore,the data of online retailers of Meituan.com was collected and combined with Baidu map and Baidu heat map data.Then,we adopted the methods such as spatial statistics and geodetector to explore the geography and determinants of O2O online retailers in Zhengzhou urban area.The main conclusions are 1)The spatial development of O2O online retailers is characterized by significant global high-value agglomeration.2)The agglomeration areas of different types of O2O online retailers are different.Most of them are concentrated in the old urban area within the Third Ring Road of Zhengzhou City,forming five comprehensive agglomeration areas.3)The areas with the high e-commerce development level are mainly concentrated in the northeast and southwest of the x-shaped region formed by the intersection of Lianyungang-Lanzhou and Beijing-Guangzhou railways.Erqi Square and Guomao 360 Plaza are at the highest development level,followed by Zhongyuan Wanda Plaza and Daxue Middle Road.The development level at other areas is relatively low.4)Zhengzhou’s O2O commercial pattern is highly dependent on physical business.The population distribution,especially the population distribution during the nightlife period,plays a vital role in its spatial development,followed by accessibility.The influences of physical distance are slightly larger than that of time cost,but the difference between them is little.In addition,travelling costs have the least impact.This paper could provide certain references for urban commercial planning.

Water Environment Carrying Capacity of New Zhengdong District in Zhengzhou City

Taking sections of the Dongfeng Canal, the Xionger River and the Wei River in New Zhengdong District for example, this paper applied water environment capacity to analyze the carrying capacity of surface water environment in the east development zone of the city. The analysis shows that carrying capacity of surface water environment in the study area is not good, carrying capacity of 3 studied waters for TP, BOD_5 and COD is approaching to the limit. New Zhengdong District, in terms of industrial structure, should promote the projects with less water consumption, less or no discharge of wastewater, and also should enhance the sewage treatment, improve recycling rate of the reclaimed water, and reduce the negative impact of sewage and pollutant discharge on environment.

Occurrence Probability Evaluation of the Maximum Potential Earthquake on the Faults in Zhengzhou City

According to the results of estimation of the maximum potential earthquake in the project of ＂The Active Fault Detection and Seismic Risk Evaluation （Phase H） of Zhengzhou City＂, the near east-west trending Laoyachen fault and Shangjie fault are developed in the urban area. The Laoyachen fault was not active in the Quaternary, but the Shangjie fault may have the potential of generating M5.0 - 5.5 earthquakes. In order to get the probability of occurrence of maximum potential earthquakes, we delineate the statistical areas and the potential source areas and calculate the seismicity parameters and the space distribution functions. Our study shows that the probability of occurrence of an earthquake with M〉 5.0 on the faults in Zhengzhou city is 6% in the next 50 years and 11% in the next 100 years.

Evaluation, simulation, and optimization of land use spatial patterns for high-quality development: A case study of Zhengzhou city, China

High-intensity land use and resource overloaded-induced regional land use spatial pattern(LUSP)are essential and challenging for high-quality development.The empirical studies have shown that a scientific land uses spatial layout,and the supporting system should be based on a historical perspective and require better considering the double influence between the current characteristics and future dynamics.This study proposes a comprehensive framework that integrates the resource environment carrying capacity(RECC)and land use change(LUC)to investigate strategies for optimizing the spatial pattern of land use for high-quality development.China’s Zhengzhou city was the subject of a case study whose datasets include remote sensing,spatial monitoring,statistics,and open sources.Three significant results emerged from the analysis:(1)The RECC has significant spatial differentiation but does not follow a specific spatial law,and regions with relatively perfect ecosystems may not necessarily have better RECC.(2)From 2020 to 2030,the construction land and farmland will fluctuate wildly,with the former increasing by 346.21 km^(2) and the latter decreasing by 295.98 km^(2).(3)The study area is divided into five zones,including resource conservation,ecological carrying,living core,suitable construction,and grain supply zones,and each one has its LUSP optimization orientation.This uneven distribution of RECC reflects functional defects in the development and utilization of LUSP.In addition,the increase in construction land and the sharp decline of farmland pose potential threats to the sustainable development of the study area.Hence,these two elements cannot be ignored in the future high-quality development process.The findings indicate that the LUSP optimization based on dual dimensions of RECC and LUC is more realistic than a single-dimension solution,exhibiting the LUSP optimization’s effectiveness and applicability.

Models of Numerical Simulating of Multiaquifer in Zhengzhou City, China

In this paper, quasi\|three\|dimensional numerical simulating and optimum management model was established for evaluating and managing groundwater resources in Zhengzhou city. Based on coupling simulating model with planning model, optimum management model of groundwater resources was established. Through controlling the groundwater seepage field, environment problems caused by unreasonable extracting groundwater resources in the studied area were decreased to the minimum level, which supply scientific foundation for groundwater resource management in Zhengzhou city.

Cluster Development of Zhengzhou Urban Agriculture Based on Diamond Model

Based on basic theory of Diamond Model,this paper analyzes the competitive power of Zhengzhou urban agriculture from production factors,demand conditions,related and supporting industries,business strategies and structure,and horizontal competition.In line with these situations,it introduces that the cluster development is an effective approach to lifting competitive power of Zhengzhou urban agriculture.Finally,it presents following countermeasures and suggestions:optimize spatial distribution for cluster development of urban agriculture;cultivate leading enterprises and optimize organizational form of urban agriculture;energetically develop low-carbon agriculture to create favorable ecological environment for cluster development of urban agriculture.

Research on Dynamic Change of Regional Cultivated Land Quality and Its Influence Factors

According to the reason of quality change,cultivated land is divided into four change types: decrease,increase,land construction project and gradual change. Farmland grading factor method is used to evaluate the quality of cultivated land in Zhengzhou City. The results show that(1) the quality of cultivated land in Zhengzhou City has slightly increased during the study period. Due to the decrease in the amount of cultivated land,the production capacity has declined.(2) The impact of different types of cultivated land change on the quality of regional cultivated land is in the order of gradual change> decrease > increase > land construction project.(3) Zhengzhou City is able to maintain the quality of regional cultivated land through new cultivated land and project construction,but fails to maintain the production capacity. By analyzing the mechanism of regional cultivated land quality change in different types,the relationship between quality changes in various types of areas and overall quality changes could be analyzed,and it could provide policy recommendations for managers to formulate farmland quality and capacity protection,with significant application value.