The application of integrating comprehensive evaluation and clustering algorithms weighted by maximal information coefficient for urban flood susceptibility.

Different sub-regions of Zhengzhou city have various levels of sensitivity to flood due to the impact of urbanization. Thus, an accurate flood sensitivities assessment is a key tool for flood prevention and urban planning and development. To successfully link the urban flood sensitivity assessment with the real flood situation, a method combining clustering algorithm with comprehensive evaluation is presented. The proposed method is not affected by the classification standard of sensitivities levels and has a small and undemanding demand for flood data. First, Maximal Information Coefficient between conditional factors and flood is employed to determine the weight. Then, the different results are obtained by three clustering algorithms. Finally, a four-layer evaluation structure weighted by analytic hierarchy process is established to select the best flood susceptibility map. A case study in the Zhengzhou city, China shows that the positive scale amplification strategy is relatively best and the flood sensitivity of sub-regions in Zhengzhou city should be divided into four levels obtained by K-Means clustering. Hence, it supplies the valuable insights for the urban planning and flood mitigation.

Research on emergy evaluation method of ecological water use efficiency based on comprehensive benefits.

Scientifically evaluating ecological water use efficiency (EWUE) is an effective means to regulate the level of ecological water use in a country or a region. It is also a basic work to achieve high-efficiency use of ecological water under the current situation of water shortage. However, there were few researches on EWUE, and existing studies only focus on eco-environmental benefits generated by ecological water, without considering its impact on economy and society. An emergy evaluation method for EWUE based on comprehensive benefits was proposed in this paper innovatively. Considering the impact of ecological water use on society, economy, and eco-environment, the concept of EWUE could be defined. Then, comprehensive benefits of ecological water use (CBEW) were quantified by emergy method, and EWUE was evaluated by the comprehensive benefits of unit ecological water use. Taking Zhengzhou City as an example for calculation, from 2011 to 2020, CBEW increased from 5.20 × 1019 sej to 6.72 × 1020 sej, showing an overall upward trend, and EWUE rose from 2.71 × 1011 sej/m3 (1.27ï¿¥/m3) to 1.32 × 1012 sej/m3 (8.10ï¿¥/m3) with fluctuation. It showed that Zhengzhou City has paid enough attention to the allocation of ecological water and EWUE at a high level. The method proposed in this paper provides a new idea to evaluate EWUE scientifically, and the results can provide guidance to allocate ecological water resources to achieve sustainable development.

Potential Heavy Metals Pollution Contribution from Wash-Off of Urban Road-Dust.

Based on the different particle sizes of street dust, the potential pollution load of heavy metals from dry and wet atmospheric deposition to surface runoff in different functional areas of Zhengzhou city was estimated by using the rain-scour heavy metal index model. Compared to the EA, IA, and CA areas, RA and PA have a higher potential contribution to heavy metal runoff pollution from Road deposited sediments (RDS) than the other watersheds. Zhengzhou utilized the RDS index model to calculate pollution loads in various areas around Zhengzhou (EA, IA, CA, PA, and RA). In the different land-use areas, the RDS indices for pollutant load (RDSindex,load) and pollutant strength (RDSindex,strength) varied greatly, and the RDS index strength values increased. RDSindex,load fell in the following order: IA > RA > PA > EA. Because the RDS index incorporates RDS characteristics such as the amount of RDS, grain sizes present, RDS mobility, and associated metals, the RDSindex,load and RDSindex,strength results did not merely match variability in the amounts of RDS found or metal concentrations in the RDS in various land-use areas. Metal's presence in the dust is a direct health risk for humans and warrants immediate and effective pollution control and prevention measures in the city.

Assessment and source apportionment of water-soluble heavy metals in road dust of Zhengzhou, China.

The water-soluble concentration of heavy metals in road dust poses a considerable hazard to public health. The primary goals of the study were estimation of water-soluble contents of heavy metal, estimation of pollution indices, and source apportionment of water-soluble contents of heavy metals using UNMIX model from the road dust of Zhengzhou city. To accomplish this, inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to determine concentrations of eight heavy metals (Cr, Cu, Ni, Zn, Cd, As, Pb, and Hg), and it has been observed that Cu and Zn were the metals with the highest concentration, while Hg, Cd, and Pb were in the lowest concentration range of metals. Pollution indices, geo-accumulation index (Igeo), contamination factor (CF), and Nemerow synthetic pollution index (PIN) were calculated to assess the contamination level of water-soluble contents of these hazardous heavy metals. Igeo classified the contamination risk into a spectrum of categories ranging from unpolluted (Cr and Pb) to high polluted (Cu and Cd). For the CF results, the concentration of Cr and Pb was found to be low, similar to Igeo, while the concentrations of three heavy metals, Cu, Cd, and Hg, were found to be extremely high or excessive. The results of the PIN assessment indicated that there was an enormous risk of Hg contamination in the city and that Cu, Cd, and Zn were all within a few percent of the Hg pollution level and hence fell into the high pollution group. The UNMIX model was used for source apportionment of dissolved heavy metals and showed: Source 1 (natural sources, 10%), Source 2 (copper mine tailing contamination, 19%), and Source 3 (agricultural activities22%). Source 4 accounted for (air pollution, 15%) of the total and Source 5 accounted for (industrial activity, 34%). It is imperative that immediate and comprehensive pollution control and preventive measures be implemented in the city due to the presence of metal in the dust.

Management implications of spatial-temporal variations of net anthropogenic nitrogen inputs (NANI) in the Yellow River Basin.

It is an important content of environment management to accurately identify the time change and spatial distribution of net anthropogenic nitrogen inputs (NANI) in the river basin. In order to develop a unified management and diverse control strategy that fits the characteristics of the basin, this study establishes the NANI-S model combining the NANI model with the spatial autocorrelation analysis method, which is a quantification-analysis-control process, and takes the 70 prefecture-cities in the Yellow River Basin (YRB) as the study area. The result shows that (1) the NANI of YRB increased first and then decreased with an average NANI value of 6787.59 kg/(km2·a), showing that the overall N pollution situation of the YRB shows a trend of improvement in nitrogen (N) fertilizer input as the main source, and the average contribution rate was 47.45%. (2) There were obvious spatial differences in the NANI in the YRB because the global Moran's I fluctuated between 0.67 and 0.78. Cities with high NANI clustered in the middle and lower reaches, while low NANI clustered in the upper reaches. (3) Improving fertilizer utilization rate and industrial and domestic sewage treatment capacity was the key point of N control. Based on the results, practical policy recommendations for water pollution management were constructed, which provides a scientific basis for pollution prevention and high-quality development in the basin. In addition, this analysis method can also be applied to other basin N management studies.

Assessment of eco-economic effects of urban water system connectivity project.

As one of the large ecological infrastructures, the urban water system connectivity (UWSC) project is an important part of urban ecosystem construction. It is helpful for the scientific planning and construction of the project to systematically evaluate the effects. However, due to the complex and various effects of UWSC project, there is no complete effect system and quantitative method. Against this backdrop, the composition and mechanism of positive and negative effects of ecological economics of UWSC project were deeply analyzed to improve the composition system of eco-economic effects in this study. At the same time, the emergy theory was used to put forward the quantification method of eco-economic effect system. Taking the UWSC project in Xuchang as an example, its ecological, social, and economic effects were evaluated. The result showed that the average eco-economic effect of the project is 49.97 million dollars/year. Economic effect and ecological effect are significant, accounting for 82.49% and 15.89% of total effect, respectively. This study can provide reference for comprehensive and unified assessment of eco-economic effects of UWSC project.

Study of spatial distribution characteristics of river eco-environmental values based on emergy-GeoDa method.

River eco-environmental value assessment is indispensable for the optimal allocation of watershed water resources. In this study, river eco-environmental values were divided into the values inside and outside the river based on the energy transfer and transformation of the water cycle. Their spatial distribution characteristics (spatial distribution map, spatial autocorrelation, and spatial aggregation) of 67 regions (states, leagues, and cities) in the Yellow River Basin (YRB) were analysed by combining emergy theory and GeoDa 1.14 software (emergy-GeoDa), and the significance of the results was tested. The results showed that: (1) the eco-environmental values inside the river were higher than those outside in the YRB, proving that eco-environmental water inside the river should be guaranteed and water consumption outside the river should not occupy water inside the river from the perspective of value; (2) the spatial distributions of eco-environmental values inside and outside the river were uneven, but obvious spatial aggregations were observed; (3) high- and low-value aggregations of eco-environmental values were observed inside the river in the lower and upper reaches of the YRB, respectively; (4) high- and low-value aggregations of eco-environmental values were observed outside the river in the middle and upper reaches of the YRB, respectively. It was suggested that ecological conservation and high-quality development should be considered as the goals for consolidating the river eco-environmental values in high-value areas and promoting in low-value areas, and low-value areas should be improved by high-value areas while allocating water resources in the YRB. These results provide suggestions for the sustainable development of river eco-environmental system in the YRB from a spatial perspective. In addition, the analysis method is also applicable for studying the spatial distribution characteristics of the values generated by the water and energy cycles of other regions.

Construction of flood loss function for cities lacking disaster data based on three-dimensional (object-function-array) data processing.

Reliable loss estimation is crucial for flood risk management. As the current standard form of flood loss assessment, it is difficult to fit the Flood Inundated Depth-Loss Rate Function (FILF) due to the lack of historical data in most inland arid and semi-arid plain cities. To address the current trend of increasing flood risk, it has become increasingly important to develop a scientific and reasonable loss assessment function or model for these cities. Therefore, the flood loss rate data of several cities were transferred through amplified characteristic indices to form a loss rate transfer vector of cities lacking disaster data based on the analogy principle. Three-dimensional data processing rules were then set, including the priority sequence of object dimensional variance and the greatest correlation coefficient (CC) of the joint dimension of function and array. Finally, a FILF of cities lacking disaster data was constructed after three-level optimization. The FILF of eight property types was calculated taking Zhengzhou City, China, as the study area. The optimal function and array dimensions were F6 (Biquadratic) and D4-D6, respectively. All CCs exceeded 0.9935, with an average of 0.9971. The joint fitting results also showed that the function dimension was more sensitive to the FILF than the array dimension. The simulated total flood loss of the Jinshui District in 20 years was 2.46 billion yuan, and there was clear spatial disparity in economic loss. This study is expected to resolve the problem of the absence of a loss function in cities or regions lacking data to support urban flood risk management.

The determination of flood damage curve in areas lacking disaster data based on the optimization principle of variation coefficient and beta distribution.

Flood loss assessment is an important part of urban flood risk management, and the establishment of disaster damage curve is the key of loss assessment. Because of the limitation of data, it is difficult for cities lacking disaster data to fit the damage curve through historical data. Generally, transferring the damage curve among regions is an effective method, but there are problems of data reference and statistical uncertainty. In view of the inland plain cities lacking disaster data, the damage factor of the data reference area can be transferred to the study area by referring to the principle of analogy. Then, based on the optimization principle of the minimum variation coefficient and the maximum beta distribution probability, the citation error and statistical error in the damage factor quotation were reduced, and the relatively accurate damage factor in the study area was obtained, and then the water depth - damage factor curve was established. Thus, a generalized damage curve fitting method for cities lacking disaster data was formed, which took the regional index values as the input parameters and the damage curves as the output results. Finally, taking Zhengzhou City, China as the study area, the loss curves of 10 property types were calculated. Compared with the original data, the average variation coefficient of the optimal scheme set was reduced by 0.1; the probability of the optimal value was increased by 1.39% compared with the average value. In addition, the method test was conducted in Jinan, China, where the data were available, and it was found that the three types of errors were significantly lower than the traditional comparison method of single city as reference object. This study is expected to provide a scientific reference for the establishment of flood damage curve in cities or areas lacking disaster data.

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.

Depth prediction of urban flood under different rainfall return periods based on deep learning and data warehouse.

With the global climate change and the rapid urbanization process, there is an increase in the risk of urban floods. Therefore, undertaking risk studies of urban floods, especially the depth prediction of urban flood is very important for urban flood control. In this study, an urban flood data warehouse was established with available structured and unstructured urban flood data. In this study, an urban flood data warehouse was established with available structured and unstructured urban flood data. Based on this, a regression model to predict the depth of urban flooded areas was constructed with deep learning algorithm, named Gradient Boosting Decision Tree (GBDT). The flood condition factors used in modeling were rainfall, rainfall duration, peak rainfall, evaporation, land use (the proportion of roads, woodlands, grasslands, water bodies and building), permeability, catchment area, and slope. Based on the rainfall data of different rainfall return periods, flood condition maps were produced using GIS. In addition, the feature importance of these conditioning factors was determined based on the regression model. The results demonstrated that the growth rate of the number and depth of the water accumulation points increased significantly after the rainfall return period of 'once in every two years' in Zhengzhou City, and the flooded areas mainly occurred in the old urban areas and parts of southern Zhengzhou. The relative error of prediction results was 11.52%, which verifies the applicability and validity of the method in the depth prediction of urban floods. The results of this study can provide a scientific basis for urban flood control and drainage.

Quantitative assessment of ecological compensation for groundwater overexploitation based on emergy theory.

Ecological compensation is an important economic tool for the control and management of ecological and environmental problems. The accurate assessment of the amount of compensation is the key factor in the implementation of ecological compensation schemes. However, due to the complex and various ecological and environmental problems caused by groundwater overexploitation, there is no scientific quantitative method. Emergy theory is a new method to quantitatively study the relationship between environmental resources and social economy. Based on the literature review of ecological compensation for groundwater overexploitation, this paper puts forward a new evaluation method for using emergy loss as groundwater overexploitation ecological compensation. The emergy system diagram of environmental problems caused by overexploitation of groundwater is constructed. And the calculation methods of the emergy loss of eco-environmental problems caused by groundwater overexploitation, such as land subsidence (collapse), salt water intrusion, surface runoff reduction, vegetation deterioration, and groundwater pollution, were presented, respectively. Taking Zhengzhou as an example, the total amount of ecological compensation for groundwater overexploitation in 2014 was equivalent to 853 × 106 US dollars. The largest loss of land subsidence is 816 × 106 US dollars, which accounts for 95.64% of the total loss. It can be seen that land subsidence is the most serious in the eco-environmental problems caused by overexploitation of groundwater in Zhengzhou.

Toward flexible regulation of polyhydroxyalkanoate composition based on substrate feeding strategy: Insights into microbial community and metabolic features.

The suitable feeding strategy considering both substrate preference (enrichment stage) and flexible regulation (PHA accumulation stage) were investigated, respectively, based on intracellular polymers synthesis peculiarities of the three types of cultures (M-Ac, M-Pr and M-Bu), which were enriched correspondingly using acetic type, propionic type and butyric type substrate. Compared to M-Ac and M-Bu cultures, maximum PHA content (PHAm) of M-Pr exhibited the most stable responses to varying fractions of propionic acid (fPr) of the substrate. The substrate composed of acetic acid and propionic acid (Mix-AP) demonstrated higher efficiency in regulation of polymer composition than that composed of butyric acid and propionic acid (Mix-BP). For the whole process of three-stage MC PHA production, propionic acid-dominated acidification products should be used for the long-term enrichment of PHA producers, and acidification products mainly composed of propionic and acetic acid are preferred considering the regulation of polymer composition in PHA accumulation stage.

Effect of irrigation amount and fertilization on agriculture non-point source pollution in the paddy field.

It is the key point to reveal the effect of irrigation water and fertilization conditions on the agriculture non-point pollution in the paddy field. In this study, the estimation model of agricultural non-point source pollution loads at field scale was established on the basis of agricultural drainage irrigation model and combined with pollutant concentration predication model. Based on the estimation model of agricultural non-point source pollution in the field and experimental data, the load of agricultural non-point source pollution in different irrigate amount and fertilization schedule in paddy field was calculated. The results showed that the variation of field drainage varies greatly under different irrigation conditions, and there is an "inflection point" between the irrigation water amount and field drainage amount. The non-point pollution load increased with the increase of irrigation water and showed a significant power correlation. Under the different irrigation condition, the increase amplitude of non-point pollution load with the increase of irrigation water was different. When the irrigation water is smaller, the non-point pollution load increase relatively less, and when the irrigation water increased to inflection point, the non-point pollution load will increase considerably. In addition, there was a positive correlation between the fertilization and non-point pollution load. The non-point pollution load had obvious difference in different fertilization schedule even with same fertilization level, in which the fertilizer pollution load increased the most in the period of turning green to tillering. The results provide some basis for the field control and management of agricultural non-point source pollution.

Analysis of groundwater variation in the Jinci Spring area, Shanxi Province (China), under the influence of human activity.

Jinci Spring is one of the most famous karst spring in Northern China and is the main drinking and irrigation water source of Taiyuan city, Shanxi Province. It has special significance in terms of humanities and water resources. Because of the continuous over-exploitation of groundwater, the water level of groundwater has been decreased significantly. The flow of Jinci Spring has decreased year by year since the 1970s, and in 1994 it cut off completely. The flow cutoff has brought huge losses to the local economy and negatively impacted the ecological environment. From the hydrogeological conditions of Jinci Spring area to study, the dynamic change in karst groundwater level will provide a basis for the protection and rational exploitation of karst water in the spring area. The previous research on Jinci Spring area was limited to the spring flow and water level changes, lack of analysis to the overall spring area and the decay process of spring flow. This paper takes the overall spring area as research object. According to groundwater level data over 1961-2012, the period is divided into two phases of decline and recovery. Human activities in the region and corresponding groundwater evolution at various stages were systematically analyzed, and the reservoir capacity was calculated for each period of decline. The results show that the average reservoir capacity decreased from 920 (1954-1960) to 116 (1961-1977) to 31 (1978-1994) million m3. The important effect of "Water Resumption" project on groundwater in the area during the remediation period was also analyzed. In the light of observed increases in groundwater level during this stage, the project has a notably positive effect.

Application of MIKE SHE to study the impact of coal mining on river runoff in Gujiao mining area, Shanxi, China.

Coal mining is one of the core industries that contribute to the economic development of a country but deteriorate the environment. Being the primary source of energy, coal has become essential to meet the energy demand of a country. It is excavated by both opencast and underground mining methods and affects the environment, especially hydrological cycle, by discharging huge amounts of mine water. Natural hydrological processes have been well known to be vulnerable to human activities, especially large scale mining activities, which inevitably generate surface cracks and subsidence. It is therefore valuable to assess the impact of mining on river runoff for the sustainable development of regional economy. In this paper, the impact of coal mining on river runoff is assessed in one of the national key coal mining sites, Gujiao mining area, Shanxi Province, China. The characteristics of water cycle are described, the similarities and differences of runoff formation are analyzed in both coal mining and pre-mining periods. The integrated distributed hydrological model named MIKE SHE is employed to simulate and evaluate the influence of coal mining on river runoff. The study shows that mining one ton of raw coal leads to the reduction of river runoff by 2.87 m3 between 1981 and 2008, of which the surface runoff decreases by 0.24 m3 and the baseflow by 2.63 m3. The reduction degree of river runoff for mining one ton of raw coal shows an increasing trend over years. The current study also reveals that large scale coal mining initiates the formation of surface cracks and subsidence, which intercepts overland flow and enhances precipitation infiltration. Together with mine drainage, the natural hydrological processes and the stream flows have been altered and the river run off has been greatly reduced.