Risk assessment of hybrid rain harvesting system and other small drinking water supply systems by game theory and fuzzy logic modeling

Dynamic impact assessment of urban floods on the compound spatial network of buildings-roads-emergency service facilities

There are complex interactions among urban spatial elements in rainstorm scenarios. Road interruptions may cause isolation between partially submerged buildings and emergency service facilities, thereby affecting the recovery capability of flooded buildings and the accessibility of emergency service facilities. This study constructed a compound spatial network of urban buildings-roads-emergency service facilities, and analyzed the complex dynamic impacts of time-varying dynamic floods on building risk, road risk, and emergency service accessibility. Firstly, a refined flood risk assessment at the building scale was carried out in combination with flood inundation, building vulnerability, population, vulnerable areas, underground buildings, and life facilities. Secondly, betweenness centrality indicator in complex networks was used to calculate road traffic capacity and collapse threshold, and the accessibility of emergency service facilities is calculated based on road traffic capacity. Finally, the interaction and feedback relationships between the compound spatial network were analyzed. The results show that: (1) Flooded building comprehensive risk analysis reveals that floods have a significant impact on residential and commercial land use, and high-risk flood areas are mainly concentrated in the central region of study area. (2) The road network has a collapse threshold, and the fluctuating state of emergency service accessibility is significantly influenced by road traffic capacity. (3) Roads act as "bridges" connecting buildings and emergency service facilities, leading to the redistribution of building flood comprehensive risk and emergency service accessibility, presenting complex dynamic changes over time. Additionally, submerged roads also affect the accessibility of emergency service facilities around flooded buildings, reducing the recovery capacity of flooded buildings, and exhibiting significant heterogeneity characteristics. Future research should consider the complex impacts of floods on urban elements in order to better manage dynamic flood risk.

Security risk assessment of projects in high-risk areas based on attack-defense game model

Assessing the security risk of projects in high-risk areas is particularly important. This paper develops a security risk assessment model for projects in high-risk areas based on the target loss probability model and Bayesian game model. This model is modeled from the perspective of attack-defense confrontation and addresses the issue that traditional risk assessment focuses on the analysis of the attacker yet neglects to analyze the defender-the defender's optimum defensive information is not quantitatively determined. The risk level, optimum defensive resource value, and optimum defensive strategy of the project are determined through the analysis of a project in the high-risk area. This enables the project's risk manager to adjust the defensive resources reasonably and optimally, confirming the objectivity and feasibility of the model and offering a new benchmark for security risk assessment, which has significant practical implications.

Green Innovation in Regional Logistics: Level Evaluation and Spatial Analysis

Green innovation is imperative for the high-quality and sustainable development of the modern logistics industry. It is also key for achieving the goals of peak emissions and carbon neutrality. This study provides a way of thinking about the evaluation of the green innovation level of the logistics industry. The variance inflation factor-variance coefficient method was employed to construct an evaluation index system of the regional logistics green innovation level (RLGIL) from three dimensions. Empirical data were collected from statistical yearbooks covering 30 provinces in China from 2013 to 2017. Thereafter, the combination weighting-based GRA-TOPSIS method was applied to evaluate the RLGIL, and the spatial distribution differences and spatiotemporal evolution characteristics of inter-provincial green innovation levels were analyzed. The RLGILs in the 30 provinces were found to be generally unbalanced, and the differences between the eastern and western regions were significant. Guangdong, Jiangsu, and Zhejiang had stronger RLGILs, whereas most other provinces did not reach the average level. The RLGIL of the 30 provinces had a high positive spatial correlation and spatial aggregating effect. From a national perspective, the values for the RLGIL were generally higher in the eastern and southern regions and lower in the western and northern regions. Although significant differences were found in the RLGIL of these provinces, the overall development trend was stable.

The optimization of Low Impact Development placement considering life cycle cost using Genetic Algorithm

Low Impact Development (LID) is an effective measure in controlling the urban runoff and mitigating the non-point source pollution. The determination of LID facilities and layouts for a sub-catchment is important for designing stormwater management system. However, there are remain large uncertainty and challenge exist in determination of LID facilities when consider budget, land use, soil surface and groundwater as well as local climate etc. To address this issue, this study employed Genetic Algorithm (GA) for optimization of the selection and layout of LID. The urban runoff was simulated using Environmental Protection Agency (EPA) Storm Water Management Model (SWMM). The LID planning was encoded as 0 and 1 in GA algorithm. The multiple objectives which include runoff reduction, area of LID and life cycle cost were selected as optimization targets. To test the model performance, the Airport Economic Zone in Tianjin, China was chosen as the study area. The results demonstrate that the combination of LID approaches are most effective measures on runoff reduction through long-term simulation (10 years' rainfall events). The impact of different weights of land area and cost on LID selection were evaluated when considering life cycle cost. Bio-Retention is preferred when considering the area of LID and Green Roof is recommended when the cost is prioritized. The present research proved GA is feasible for LID planning in urban area. The proposed method can help the decision-makers to determine the LID plan more scientific based on SWMM model and GA.

Safety assessment of drinking water sources along Yangtze River using vulnerability and risk analysis

Recently, the safety of drinking water sources along Yangtze River Basin is received much attention. But few works have carried out large-scale and all-round safety assessment of drinking water sources on the main stream of the whole Yangtze River Basin. In this work, 97 drinking water sources in 8 provinces of the main stream of the Yangtze River were selected as the objects to clarify the spatial distribution of the safety risk levels of drinking water sources in the whole basin and analyze the causes of drinking water source risks. The results showed that 13.4%, 55.7%, 25.8%, 5.1%, and 0% of the 97 drinking water sources were classified as low, moderate, considerate, high, and very high respectively, according to the safety risk level. This indicated that the safety risk of drinking water sources in the mainstream of Yangtze River is generally low, but there are also a number of high safety risk drinking water sources. And the safety risk degree of the lower and upper reaches in the mainstream of Yangtze River is generally higher than that of the middle reaches. The current situation of drinking water sources along the mainstream of Yangtze River could be attributed to the superposition of human activities and natural background factors. This study could contribute to the government's targeted management and control of safety risk sources for drinking water sources along the Yangtze River Basin.

An optimization method coupled the index-overlay method with entropy weighting model to assess seawater intrusion vulnerability

Seawater intrusion poses a serious threat to coastal areas around the world. The purpose of this study was to develop a comprehensive approach to assess the vulnerability of saltwater intrusion. The powerful decision-making technique GALDIT was firstly selected, and its inherent weights are the origin of the subjective method. The entropy method was then integrated to reasonably determine the objective weight of this basic structure. Furthermore, to balance conflicts between subjective and objective methods, game theory was intruded upon. The result of the sensitivity analysis showed a correlation coefficient between the effective weights and theoretical weights of the normal method, entropy theory, and game theory of 0.66, 0.89, and 0.94, respectively. Meanwhile, the best correlation coefficient between the vulnerability indices and the values of 38 monitoring wells was obtained by the game model. Finally, the optimal weights of G, A, L, D, I, and T were 0.096, 0.153, 0.220, 0.320, 0.150, and 0.061, respectively. The study area was finally classified into regions with high, moderate, and low vulnerability, accounting for 11.4%, 24.9%, and 63.7% of the area. The paper included that the optimization of GALDIT through game theory gives a more accurate assessment of the groundwater vulnerability to seawater intrusion.

Water quality characteristics and assessment of Yongding New River by improved comprehensive water quality identification index based on game theory

The Yongding New River is essential for the water supplies of Tianjin. To date, there is no comprehensive report that assesses the year-round water quality of the Yongding New River Main stream. Moreover, little attention has been given to determining a combined weight for improving the traditional comprehensive water quality identification index (ICWQII) by the game theory. Seven water quality parameters were investigated monthly along the main stream of the Yongding New River from May 2018 to April 2019. Organic contaminants and nitrogen pollution were mainly caused by point sources pollution, and the total phosphorus mainly by non-point source pollution. Dramatic spatio-temporal variations of water quality parameters were jointly caused by different pollutant sources and hydrometeorological factors. In terms of this study, an improved comprehensive water quality identification index (ICWQII) based on entropy weight or variation coefficient and traditional CWQII underestimated the water qualities, and an ICWQII based on the superstandard multiple method overvalued the assessments. By contrast, water qualities assessments done with an ICWQII based on the game theory matched perfectly with the practical situation. The ICWQII based on game theory proposed in this study takes into account not only the degree of disorder and variation of water quality data, but also the influence of standard-exceeded pollution indicators, whose results are relatively reasonable. All findings and the ICWQII based on game theory can provide scientific support for decisions related to the water environment management of the Yongding New River and other waters.

Performance Evaluation of Enhanced Bioretention Systems in Removing Dissolved Nutrients in Stormwater Runoff

Bioretention has great potential in managing and purifying urban stormwater runoff. However, information regarding the removal of nutrients in bioretention systems with the use of media, plants, and saturated areas is still limited. In this study, three devices of control, conventional bioretention (DS), and strengthened bioretention (SZ) were investigated to enhance the simultaneous removal of nitrogen and phosphorus. The experimental column SZ showed the best performance for total phosphorus (TP), ammonia (NH4+-N) and total nitrogen (TN) removal (85.6–92.4%, 83.1–92.7%, 57.1–74.1%, respectively), whereas DS columns performed poorly for NH4+-N removal (43.6–81.2%) under different conditions. For the removal of nitrate, the columns of Control and DS exhibited negative performance (−14.3% and −8.2%) in a typical event. Further evaluation of water quality revealed that in the early stages of rainfall, the effluent of the SZ column was able to reach quality standards of Grade IV for surface water in China. Moreover, although the ion-exchange and phosphate precipitation occurred on the surface of the media, which were placed in the saturation zone, it did not change the surface crystal structure.