This article is selected from the journal of the Chinese Academy of Engineering, China Engineering Science, Issue 1, 2023
Authors: Jin Wenbo, Yang Jixing, Liu Shaofei, Zhang Yunlei, Xiao Tiantian
Source: Research on the inference and response method of rainstorm disaster in megacities[J].Strategic Study of Chinese Academy of Engineering,2023,25(1):20-29.)
Editor's note
Megacities generally have the characteristics of high population density, developed economy, and complex urban functions. Due to the high concentration of population, resources, environment, facilities and other factors, one disaster accident in a megacity often leads to the occurrence of other disasters, resulting in a magnifying effect and then bringing about extremely bad negative impacts. In recent years, heavy rainfall in megacities in mainland China has occurred frequently, seriously threatening the safety of people's lives and property and social stability.
The first issue of the journal of the Chinese Academy of Engineering, China Engineering Science, in 2023 published an article entitled "Research on the Deduction and Response Methods of Rainstorm Disaster Disruption in Megacities" by the research team of Yang Jixing, a senior engineer from the Big Data Center of the Ministry of Emergency Management. This paper deeply reviews the rainstorm chain disaster system, studies the important role of the current waterlogging disaster trend deduction model and various deduction simulation results in the process of disaster chain blocking, puts forward the idea of combining simulation deduction and comprehensive response, and clarifies the response strategies of various emergency subjects in the process of megacity catastrophe response. At the same time, the overall response ideas of rainstorm chain disasters in megacities based on "planning", "monitoring", "deduction", "coordination" and "rescue" are proposed, and five coping methods are proposed, such as multi-departmental plan coordination, multi-dimensional information aggregation, multi-level accurate early warning, and multi-team linkage scheduling in sudden disaster scenarios, including a complete comprehensive plan system, building a monitoring and early warning network, improving the application of simulation and deduction, strengthening joint response capabilities, and consolidating precision rescue capabilities. In addition, development suggestions were put forward in the formulation of policies and regulations, the preparation of standards, the application of intelligent technology, the promotion of intelligent early warning and directional release technology, and the formation of a new pattern of "national emergency".
I. Preface
Megacities generally have the characteristics of high population density, developed economy, and complex urban functions. Due to the high concentration of factors such as population, resources, environment, and facilities, one disaster accident often leads to the occurrence of other disasters, resulting in a magnification effect, and then bringing extremely bad negative impacts. In recent years, Wuhan, Guangzhou, Beijing, Shenzhen, Zhengzhou and other cities have frequently been hit by heavy rainfall, which has triggered serious rainstorm chain disasters, which can be described as "waterlogging when it rains, and paralysis when it is waterlogged", exposing the problems of insufficient emergency response and disposal capacity of extreme rainstorm weather in mainland megacities, and government departments at all levels have also begun to pay close attention to and begin to formulate and take measures to solve the problem. Therefore, it has become an urgent task to strengthen the research on emergency management of natural disasters, especially those caused by urban rainstorm chains, on the basis of the theoretical research of disaster chains.
Since the 18th National Congress of the Communist Party of China, the CPC Central Committee has attached great importance to disaster prevention and mitigation, put forward a series of clear requirements, made a series of major deployments, and launched a series of major measures. It is emphasized that it is necessary to firmly establish the concept of disaster risk management and comprehensive disaster reduction, adhere to the principle of prevention and the combination of prevention and response, adhere to the unity of normal disaster reduction and abnormal disaster relief, and strive to realize the transformation from focusing on post-disaster relief to focusing on pre-disaster prevention, from responding to a single disaster to comprehensive disaster reduction, and from reducing disaster losses to reducing disaster risks. The Ministry of Emergency Management, the Ministry of Housing and Urban-Rural Development, the Ministry of Water Resources and other departments have also issued a series of construction orientation and governance standards for the prevention and control of urban waterlogging disasters, which provide a lot of guidance for cities at all levels to carry out disaster prevention and mitigation work against rainstorm chain disasters. However, the monitoring and response of heavy rain chain disasters in megacities is an extremely complex system engineering, involving many factors and many industry sectors such as urban industrial hazards, public places, infrastructure, natural disasters, public transportation, public health emergencies, etc., which brings great challenges to the comprehensive response of municipal administrative units before the disaster and the emergency response of full-time administrative departments in the process of disaster spread. Although the mainland's comprehensive natural disaster monitoring and early warning capacity has been continuously improved in recent years, there are still problems in megacities, such as the imperfect comprehensive monitoring and early warning system, the imperfect joint management and coordination mechanism, and the insufficient cross-domain linkage response capacity.
In order to study the comprehensive impact of rainstorm chain disasters on megacities, we have conducted in-depth and detailed comprehensive research and analysis on the disaster chain, which has attracted extensive academic attention since the concept of disaster chain was proposed in the disaster science system. The complex system of disaster chain can be divided into disaster-bearing environmental system, disaster-causing factor system and disaster-bearing body system, and the interaction between the three systems is coupled with each other to induce a series of disaster events, thus forming a disaster chain, and the disaster chain can be divided into two types: serial disaster chain and concurrent disaster chain. From the perspective of the occurrence process of disasters, the evolution process of the disaster chain can be divided into the early stage of disaster evolution, the middle stage of disaster evolution and the late stage of disaster evolution, and the characteristics of different stages of disaster evolution are described and studied, and the disaster chain is divided into fracture and slip chain, periodic cycle chain, tributary main stream chain, branch and leaf vein chain. Disaster transmission links such as broken chain links enrich and supplement the research on disaster chains.
This paper intends to comprehensively analyze the supporting role of the deduction results in the process of disaster chain blocking by deeply excavating the disaster chain disaster system of megacities, combining the special simulation and deduction capabilities and the practical application scenarios of the results. Based on simulation and deduction, the idea of combining multi-department coordination and linkage with comprehensive response is proposed, and the response strategies and joint response capabilities of various emergency subjects in the process of comprehensive response to catastrophes in megacities are refined, and countermeasures are put forward for various departments in megacities in the process of monitoring, early warning and comprehensive disposal of rainstorm chain disasters, which has both academic exploration and practical application value.
2. Problems in coping with heavy rain disasters in megacities
In November 2014, the State Council issued the Notice on Adjusting the Criteria for Dividing the Scale of Cities, which stipulates that cities with a permanent urban population of between 5 million and 10 million are considered megacities, and cities with a permanent urban population of more than 10 million are considered megacities. According to the "Statistical Chart of Economic and Social Development: Basic Situation of the Population of Mega and Mega Cities in the Seventh National Population Census" released by the National Bureau of Statistics, there are 7 megacities in the country, namely Shanghai, Beijing, Shenzhen, Chongqing, Guangzhou, Chengdu and Tianjin, and 14 megacities, namely Wuhan, Dongguan, Xi'an, Hangzhou, Foshan, Nanjing, Shenyang, Qingdao, Jinan, Changsha, Harbin, Zhengzhou, Kunming and Dalian. For the sake of expression, these 21 cities are collectively referred to as megacities in this article.
In order to deeply study the various impacts of megacities in the face of heavy rainfall and its chain disasters, and clarify the deep-seated causes of related impacts, taking the rainstorm and waterlogging disasters in Beijing, Shenzhen, Zhengzhou, Hangzhou, Wuhan and other cities as examples, this paper analyzes the various problems that emerge in the process of disaster response of administrative departments at all levels and enterprises and institutions in the cities, and summarizes the impact characteristics of megacities in the face of heavy rainfall disasters, so as to put forward countermeasures.
According to the comprehensive analysis of the data of multiple disaster reviews, during the development of waterlogging disasters, departments at all levels in the city not only did not pay enough attention to the prevention and deployment in the early stage, but also delayed response caused by the lack of coordination of emergency plans, there were vague measures caused by imprecise response strategies, there was also the lack of unified command caused by the chaos of organizational structures, there were ineffective mobilization caused by the lack of early warning issuance, and casualties caused by weak awareness of prevention. In view of the various events that emerge in the course of disasters, the deep-seated causes of them are analyzed from the perspective of disaster mitigation and response, and the following characteristics of disasters can be obtained.
(1) The impact of disasters is "spiraling"
In the process of disaster development and spread, water on the ground, water into underground space, mountain floods, debris flows and other chain disasters occur frequently, and a large number of underground power distribution rooms have further caused power and communication interruptions in the city, which not only affects the people's spontaneous disaster avoidance and relief, but also hinders the command and dispatch of the city administrative department, which in turn leads to the further expansion of the impact of the disaster, forming a "spiral" of the degree of disaster impact.
(2) "Lack of guidance" for people to avoid disasters
In the process of disaster spread and development, there is no corresponding government department to issue specific disaster avoidance instructions or disaster reduction guidelines for the people, people in urban areas go out to commute as usual, residents in mountainous areas do not take shelter in advance, some public facilities are not suspended in time, and some areas prone to flooding are not prohibited from entering. A large number of people lack professional knowledge to deal with complex and changeable disasters, resulting in many casualties.
(3) Disaster analysis is "all human"
In the process of long-term disaster development, megacities will face a complex situation of overlapping disasters such as reservoir bursting and overflowing, severe urban waterlogging, flooding and debris flow in mountainous areas, large-scale power outages and communication interruptions in urban areas, and it is very easy for casualties to occur in multiple regions at the same time. However, due to the lack of rapid and accurate analysis capabilities, the command and dispatch organization can only mechanize the itemized disposal according to the single disaster response plan, resulting in the failure to respond to secondary disasters and various emergencies in a timely manner, resulting in serious consequences.
(4) Departmental coordination "separate work"
One of the main reasons for the lack of disaster analysis capabilities, the lack of accurate disaster warning information, and the slow response to disasters is that local administrative departments have operational barriers in response plans, monitoring data, and coordination. A number of different departments involved in disaster response have formed a relatively closed monitoring, analysis, and response system. Whether it is data collection and application, development trend analysis, or rescue and actual combat, they are all restricted by departmental barriers, resulting in each department "working in its own way" in the face of sudden catastrophes.
(5) The command structure "has no leader"
The consequence of the strict departmental barriers is the lack of a unified command and dispatch organization in response to catastrophes, and the repeated dispatch and deployment of multiple command systems, which has caused a great waste of human resources, material resources, monitoring results and time resources. At the same time, the lack of information exchange between multiple command agencies has made each independent system "blind man touching the elephant", and there is a lack of unified command organization for comprehensive scheduling, which has failed to form a joint force in the process of disaster response.
In summary, in the process of responding to heavy rain disasters in megacities, the lack of multi-departmental coordination capabilities, the lack of monitoring networks, the failure to issue early warning information, and the chaos of command and dispatch systems have greatly restricted the disaster response capabilities of local administrative departments and ordinary people.
3. Deduction of chain disasters and application of chain disconnection
(1) Research on simulation and deduction technology and analysis of disaster chain
From the perspective of traditional theory, there are three main research methods of urban waterlogging: hydrological method, hydraulic method, and hydrodynamic coupling method. Most of the hydrological models are process models, with the Rainstorm Flood Management Model (SWMM) and EF Walker (InfoWorks) model being the most typical, and the hydraulic method has also been applied in the process of water flow propagation in some complex river networks at home and abroad, and the hydrodynamic coupling model has also been used in many applications in China, and has formed models and systems serving the actual combat in the Pearl River Delta region, the Yangtze River Delta region, the cities along the middle and lower reaches of the Yangtze River and the Sichuan Basin.
At the same time, the domestic research team used big data to build a waterlogging risk analysis and evaluation model covering multiple cities, and based on the results of comprehensive waterlogging risk assessment, combined with the information of rescue materials and rescue teams in the city, the rescue resources in the disaster response process were allocated in advance, and the rescue path planning was comprehensively analyzed and displayed. At present, the relevant models and systems have played an important role in the daily risk monitoring and comprehensive response to local disasters in the flood season of the Ministry of Emergency Management.
Through simulation and deduction, the rainfall process, waterlogging process and various risk points in the process of urban waterlogging disasters can be deduced and analyzed, so as to help improve the predictability, accuracy and scientificity of various departments and units at all levels in the city in dealing with rainstorm chain disasters, and provide effective support for blocking the rainstorm disaster chain.
At the same time, combined with the disaster chain theory mentioned above, the rainstorm disaster chain of megacities is sorted out, and the two disaster chain systems of waterlogging and flash flood, which have the greatest impact on cities, are analyzed, and the rainstorm disaster chain of megacities can be sorted out to obtain Figure 1.
Fig.1 Comprehensive risk assessment and auxiliary support system for urban waterlogging
(2) Analysis of the secondary disaster chain of rainstorm and waterlogging
According to the analysis of the main logistic relationship of the rainstorm \u2012 waterlogging disaster chain, the secondary disaster chain caused by rainstorm \u2012 waterlogging mainly includes seven categories: surface road waterlogging, underground space flooding, power supply interruption, communication network interruption, public transportation interruption, water ingress of production enterprises and damage to water conservancy facilities. According to the summary and conciseness, the support capacity of broken chain based on the simulation results is mainly reflected in the following aspects.
1. Heavy rain \u2012 Waterlogging \u2012 Flooding on the ground
Ground water is the main manifestation of waterlogging disasters, which is easy to cause many types of accidents and hidden dangers, and at the same time, it will also drive part of the cover to affect the normal operation of urban flood drainage and flood prevention facilities, and affect the normal operation of urban functions and the safety of people's lives and property.
Through the deduction and simulation model analysis, the water range, water depth and water propagation process of urban land can be analyzed and displayed. Then, the water-prone points and disaster-prone areas in the city are plotted in advance.
Local governments can use the results of the plotting, with the cooperation of multiple departments such as water conservancy, housing and construction, urban management, emergency response, and gardening, to work together in sponge city planning, urban drainage zoning planning, urban drainage equipment and facilities construction, urban drainage system construction, urban waterlogging disaster prevention and rescue capacity building, urban soil and vegetation water storage planning, etc., to comprehensively improve the city's water storage capacity and reduce the water depth of urban areas.
At the same time, the urban publicity, transportation, and cultural and tourism departments need to carry out targeted hierarchical early warning and directional release and disposal based on the results of simulation and deduction, and the fire rescue team and drainage group need to analyze all kinds of hidden disasters in the city in advance in combination with simulation and deduction, and cooperate comprehensively with multiple departments to achieve comprehensive emergency response for the whole people in combination with the people, so as to achieve the purpose of breaking the chain and reducing disasters.
2. Heavy rain \u2012 Waterlogging \u2012 Flooding of underground spaces
Flooding of underground space is the main form of waterlogging disaster, which can easily cause great damage to people, facilities and equipment in the space, and then cause the disability of power supply, transportation and a large number of other urban infrastructure. In the "7.21" rainstorm in Beijing and the "7.20" heavy rainstorm in Zhengzhou, the main cause of a large number of casualties was the flooding of underground space.
Combined with the results of the ground water model, the prediction and analysis of the inundation duration, flooding trend and severity of the underground space in the city can be formed, and based on the relevant analysis results, the underground space flooding warning can be accurately issued to the housing and construction, transportation, subway operation and other departments in advance.
At the same time, the jurisdiction units of the underground space (parking lots, basements, underground distribution stations) will comprehensively reduce the risk of flooding in the underground space and achieve the purpose of breaking the chain.
3. Heavy rain \u2012 Waterlogging \u2012 Power supply interruption
The interruption of power supply will lead to the shutdown of urban water conservancy facilities, communication networks, transportation and a large number of urban infrastructure, which will further expand the impact of waterlogging disasters on the one hand, and seriously hinder the smooth progress of personnel evacuation, team rescue and information exchange on the other hand, which will affect the rescue work.
Power supply interruption is one of the biggest obstacles to early warning and rescue work, combined with the simulation results of underground space water ingress, comprehensively analyze the distribution of power supply equipment and underground power generation sites, predict the power supply interruption area, and based on the relevant prediction results, issue early warnings to power-related enterprises in advance.
Based on the results of simulation and deduction, it can be suggested that enterprises such as the State Grid should do a good job in the water avoidance design of lines and equipment when carrying out overall planning, and at the same time combine early warning to keep emergency power generation vehicles near key locations to ensure that key locations such as command centers and hospitals are not affected by power outages. Through redundancy design and risk avoidance design, the purpose of chain disconnection is achieved.
4. Heavy rain \u2012 Waterlogging \u2012 Communication network disruption
The interruption of the communication network will divide the city into "isolated islands", which will have a great impact on the issuance of command and dispatch instructions and the reporting of people's help information. It also makes it impossible for command and decision-making personnel to quickly and clearly understand the whole picture of the disaster event, and the overall research and judgment of the event is inaccurate.
Based on the results of simulation and deduction, the water inlet and power interruption in the underground space can be used as the evaluation criteria, and the equipment points of the communication base station and tower can be superimposed, and the changes in the communication network interruption area can be comprehensively analyzed and predicted, and an early warning can be issued to the communication management department.
Combined with the results of the comprehensive analysis of power supply and network interruption, the ICT management department can take the lead in building an emergency communication recovery mechanism in a disaster state, the communication network operator can take the lead in establishing an emergency communication support team in a crisis state, and the emergency management department can take the lead in building an emergency communication means in a disaster situation, so as to achieve the purpose of disconnecting the link and blocking the disaster.
5. Heavy rain \u2012 Waterlogging \u2012 Disruption of public transport
On the one hand, the interruption of public transportation affects the travel and transfer of the people, and the interruption of the communication network is superimposed, which is easy to bring about the psychological state of crowd gathering and panic. On the other hand, it will also force the public transportation facilities in operation to stop, affecting the life safety of passengers.
Through the simulation of the situation of power supply and communication networks, a comprehensive evaluation can be carried out on the information such as the interruption area, the duration of the interruption, and the number of people affected. In addition, the traffic management department and the public transport operating company shall issue early warnings to the public in advance to reduce travel and public transport suspension, and the relevant early warning information shall be jointly constructed by the urban traffic management department and the public transport operating company to strengthen the emergency stop and disaster avoidance ability of public transport in the face of emergencies, so as to achieve the purpose of disconnecting the chain and reducing disasters.
6. Heavy rain \u2012 Waterlogging \u2012 Water ingress from production enterprises
Production enterprises are limited by their special conditions, and are prone to various secondary accidents such as flooding, combustion, explosion and even collapse. It has a serious impact on the life safety of production personnel and the property of the enterprise.
Through the model simulation and deduction, the water inlet time, inundation depth and secondary safety accident risk of the production enterprise can be deduced. Based on the results of the relevant deduction, the emergency management department will issue an early warning of shutdown and risk avoidance to the risk-related enterprises in advance, and the emergency management department can also take the lead in establishing a linkage response mechanism for waterlogging \u2012 enterprises in the jurisdiction, so as to issue early warnings to enterprises according to the trend of disaster spread and achieve the purpose of breaking the chain and reducing disasters.
7. Heavy rain \u2012 Waterlogging \u2012 Damage to water conservancy facilities
Water conservancy facilities such as sluices, dams, pumping stations and reservoirs in the city are important protective barriers in the event of disasters in the city, and all kinds of facilities are easily affected by emergencies such as power outages and flooding of sewers in urban areas, which can easily lose their relevant disposal capacity in waterlogging disaster scenarios, resulting in further expansion of the impact of disasters.
Through the simulation of the power supply and communication networks, a comprehensive assessment can be made for the location of water conservancy facilities, the duration of damage, the risk of failure, and the subsequent impact. At the same time, the water conservancy department should also strengthen the design of water conservancy facilities for urban waterlogging disasters in the construction planning, including key drainage facilities such as sluices and dams, reservoirs, pumping stations, and key regulation and control of surrounding rivers. By strengthening the robustness of the overall facility, the purpose of breaking the chain and preventing disasters can be achieved.
(3) Heavy rain \u2012 analysis of the secondary disaster chain of flash floods
Theoretically, the hydrodynamic model can better support the simulation and deduction of flash flood disasters. At present, hydrodynamics is divided into one-dimensional hydrodynamic model, two-dimensional hydrodynamic model and three-dimensional hydrodynamic model. The one-dimensional hydrodynamic model is represented by the Saint-Venan Cheng Group and is widely used; the two-dimensional hydrodynamic model adopts the shallow water equation system as the governing equation, which has prominent advantages in the areas where the water flow direction of artificial buildings such as flood control protection areas, water flow movements are complex, and the water flow direction of artificial buildings such as houses and roads is often changed; the three-dimensional hydrodynamic model is rarely used in the field of flash flood simulation and deduction.
Floods in small watersheds in mountainous areas are characterized by strong suddenness and great destructiveness, and are a difficult and weak link in flood prevention work. At present, the prevention and control of flash floods is mainly based on non-engineering measures, and the combination of non-engineering measures and engineering measures is used for key prevention and control areas. With the deepening of construction, in terms of non-engineering measures, it is facing a transformation from "perceptual" to "intelligent", that is, the empirical forecast of the results of the static risk area obtained from the investigation and evaluation of flash flood disasters to the real-time forecast of simulated early warning of flash flood digital model. The simulation and deduction of relevant models can provide effective support for the severity of flash floods and the development trend of various secondary disasters, and the specific support capacity is reflected in the following disconnection applications.
According to the analysis of the main logistic relationship of the torrential rain \u2012 flash flood disaster chain, the secondary disaster chain caused by heavy rain \u2012 flash flood mainly includes six categories: public transportation interruption, power supply interruption, communication network interruption, infrastructure damage, flood outbreak in mountainous areas and geological disasters.
1. Heavy rain \u2012 flash floods \u2012 Public transport disruption
On the one hand, the interruption of public transportation affects the travel and transfer of the people, and the interruption of the communication network is superimposed, which is easy to bring about the psychological state of crowd gathering and panic, and on the other hand, the road interruption greatly increases the difficulty of rescue in the affected mountainous areas.
Based on the results of flash flood simulation, the research and analysis of the coverage area of the river basin was carried out, the scope of the disaster was assessed, the information was shared with the urban traffic management department, and the public was issued in advance to reduce travel and public transportation outage.
2. Heavy rain \u2012 flash floods \u2012 Power supply interruption
On the one hand, it will further expand the impact of flash floods, and on the other hand, it will seriously hinder the smooth progress of personnel evacuation, team rescue and information exchange, which will affect the rescue work.
Based on the results of flash flood simulation and deduction, the coupling analysis of power transmission lines in mountainous areas is carried out in advance, and early warning information is sent to the power department in time, and the affected areas that are susceptible to power supply interruption can also be marked in advance. In addition, the results of the analysis can be used to put forward targeted suggestions to the State Grid Corporation, such as water avoidance design, daily line inspection, lightning protection design, etc. in the overall planning. Before the annual flood season, emergency power generation vehicles can also be kept at key locations to achieve the purpose of chain disconnection through redundancy design and risk avoidance design.
3. Heavy rain \u2012 flash floods \u2012 Communication network disruption
The interruption of the communication network will completely turn the affected mountainous areas into "isolated islands", which will have a great impact on the issuance of command and dispatch instructions and the reporting of people's help information. It also makes it impossible for command and decision-making personnel to quickly and clearly understand the whole picture of the disaster event, and the overall research and judgment of the event is inaccurate.
Through simulation and deduction, various equipment such as emergency communication vehicles can be configured in advance to ensure the smooth communication network in mountainous areas. Government departments can also take the lead in establishing an emergency communication recovery mechanism under emergency conditions, and communication network operators are responsible for building emergency communication support teams to achieve the purpose of disconnecting links and blocking disasters.
4. Heavy rain \u2012 flash floods \u2012 Damage to infrastructure
Infrastructure such as tunnels, bridges, culverts, dams, and embankments are the lifeblood of cities, but they are prone to water accumulation, collapse, and outburst due to the impact of flash floods.
Through the simulation and deduction of the flash flood model, the impact of infrastructure is predicted and analyzed, and the secondary disasters that may be caused by the damage to the facilities are combined to issue evacuation warnings to the public. At the same time, the water conservancy department can combine the analysis results to strengthen the infrastructure guarantee in the development process of flash flood disasters, and achieve the purpose of breaking the chain and preventing disasters by strengthening the robustness of the overall facilities.
5. Heavy rain \u2012 flash floods \u2012 Flooding
Damage to infrastructure will increase the risk of flash floods, and in 2022, large-scale flash floods occurred in Yunnan, Sichuan and other places, resulting in damage to village facilities and people being stranded.
According to the trend of flash flood spread, the time and development trend of floods are deduced, early warning instructions are issued in a timely manner, and government departments take the lead in building a perfect flash flood prevention mechanism, and issue early warnings to the people in advance through loudspeakers, telephones, manual shouting, etc., and at the same time, strengthen the public's awareness of disaster prevention and mitigation, actively publicize emergency avoidance methods, and take multiple measures to achieve the purpose of breaking the chain.
6. Heavy rain \u2012 flash floods \u2012 Geological hazards
Flash floods will indirectly lead to the occurrence of geological disasters, landslides or debris flows, increase the risk of water cuts, power outages, and circuit breaks, increase the difficulty of rescue, and threaten the safety of people's lives and property.
According to the deduction model of geological hazard propagation trend, the data deduction is carried out to realize flood control design, disaster assessment, sensitivity assessment and disaster scope assessment, realize comprehensive analysis and prediction of geological disasters, rapid forecasting and emergency response, and effectively improve the level of geological disaster prevention and management.
Strengthen dynamic early warning, improve the level of disaster prevention and mitigation, improve emergency plans, carry out emergency drills on a regular basis, and establish a hidden danger risk investigation and monitoring mechanism led by the natural resources department, especially in disaster-prone areas, to strengthen personnel management and inspections, so as to achieve the purpose of breaking the chain and reducing disasters.
Combined with the idea of link break intervention based on simulation deduction, an overview diagram of the application idea of simulation deduction and rainstorm disaster chain break is drawn as shown in Figure 2, which can deeply understand the role that simulation deduction ability and comprehensive response mechanism can play in interrupting the disaster chain.
Fig.2 Application of simulation deduction and rainstorm disaster chain disconnection
4. Research on the response methods of rainstorm chain disasters
From the perspective of basic theoretical analysis, the mode of simulation deduction + comprehensive response can alleviate the pressure of the process of handling the chain disaster of heavy rain in megacities to a certain extent, but there are still problems in the actual combat application, such as the inability to collect monitoring information, the inconsistent response standards, the confusion of command and dispatch, the inability of the grassroots people to obtain key information, and the cluelessness of the rescue team. The main governance departments of megacities have established a set of self-contained disaster response and disposal mechanisms, which also restricts the construction of comprehensive and coordinated response capabilities of cities to a certain extent.
In order to give full play to the comprehensive response capability of multiple departments, on the basis of in-depth analysis of the generation, development and response measures of the disaster chain derived from heavy rainfall, the urban flood control and drought relief headquarters and relevant departments at all levels need to strive to strengthen the multi-departmental comprehensive response system, consolidate the multi-channel information coordination and sharing mechanism, and promote the comprehensive application of simulation and deduction results, so as to build a predictable and accurate response capability in times of disaster.
Combined with the analysis of the evolution and response methods of rainstorm chain disasters mentioned above, this paper summarizes and puts forward the overall response suggestions for rainstorm chain disasters in megacities based on the five goals of comprehensive plan, monitoring network, simulation and deduction, linkage and coordination, and precise rescue, so as to comprehensively improve the disaster response capacity of megacities from government departments to social democracy, and strengthen the robustness of cities in the face of complex and changeable disaster scenarios (see Figure 3).
Fig.3 Comprehensive response model of rainstorm disaster chain in megacities
(1) Complete the collaborative application system of the plan
1. Build a plan library
In accordance with the guidelines for writing the plan, according to the plan level, administrative division, type and other elements, the multi-departmental plan is classified and structured, and the plan database is established.
2. Establish collaborative standards and rules and regulations for the plan
For the catastrophe system of megacities, various standard documents including unified standards for professional terminology and unified standards for response levels have been formed, and corresponding rules and regulations have been promulgated for the unified response of multiple departments in emergency scenarios.
3. Promote the coordination of plans
Based on relevant systems and regulations, the emergency plans of water conservancy, meteorology, emergency response, urban management and other relevant industry departments are split and sorted out. In the scenario of heavy rain and its secondary disasters, the plan elements, professional vocabulary and response conditions of each department should be coordinated and matched, and the connection standards should be formulated to promote the convergence and linkage of the plan between various departments.
4. Organize response drills
Strengthen the dynamic management and daily application of the emergency plan, and the government departments regularly organize and carry out emergency drills for the emergency plan in the urban catastrophe scenario, and conduct special analysis and improvement of the coordination ability of the plan, so as to effectively transform the emergency plan into a solid guarantee for improving the ability to deal with emergency situations.
(2) Build a collaborative and comprehensive monitoring network
Multi-sectoral integrated monitoring is a prerequisite for the deduction of disaster development trends and follow-up response, and the construction of the integrated monitoring system focuses on the following aspects.
1. Build a collaborative monitoring network
Build a multi-departmental comprehensive monitoring network to realize collaborative monitoring and information sharing among horizontal departments such as water conservancy, transportation, urban management, public security, emergency response, and meteorology.
2. Open up information exchange channels
Establish a sound system for reporting public information and accurate information distribution, and on the basis of system construction, use the Internet, 5G, the Internet of Things, public network mass SMS and other means to build cross-level information interaction channels.
3. Improve and optimize monitoring methods
For key areas such as drainage pipe networks, traffic tunnels, subway entrances, underground spaces, ground waterlogging points, geological hazard points, densely populated areas, power facilities, communication facilities, etc., emerging technologies such as population thermal superposition, cloud-edge integration, remote sensing monitoring and microwave are used to build a high-density, multi-element, all-weather monitoring network, and optimize the monitoring network layout in combination with disaster chain elements, so as to provide guarantee for the fine assessment and early warning of urban waterlogging disasters.
4. Establish an emergency intelligence center
Establish a unified emergency response intelligence center for urban emergencies, which should have the capabilities of rapid emergency positioning, real-time aggregation of multi-department related intelligence, unified integration of event information, and analysis and presentation of intelligence results, so as to provide professional intelligence support for disaster situation analysis and comprehensive resource scheduling, and assist in improving the comprehensiveness, comprehensiveness and practicability of emergency command and decision-making.
(3) Enhance the ability to apply intelligent deduction
1. Intelligent early warning information matching
Through the multi-dimensional comprehensive analysis of chain disasters, response strategies are intelligently generated for grassroots government departments and people at different response levels, different disaster-bearing fields and different regional groups, so as to realize the intelligent early warning information generation of multi-group response targets.
2. Upgrade simulation and deduction capabilities
New technologies such as data mining and machine learning are used to mine the evolution law of multi-hazard disaster chain in heavy rain scenarios and match intelligent early warning information. Through real-time monitoring and verification, the spatial and temporal distribution and development trend of disaster risks can be predicted, and the possible scope and impact degree of disaster events can be accurately classified and matched with strategies, so as to assist relevant government departments to initiate scientific and reasonable grading plans and take appropriate measures to prevent and control crises.
3. Accurate issuance of multi-target early warnings
On the one hand, it is necessary to build a classified and accurate push system for business early warning information and related response strategies to improve the comprehensive response efficiency of government departments. On the other hand, it is necessary to form a hierarchical and precise push capacity for early warning for the grassroots and the public through various means such as radio and television, operators, and the Internet, and target specific audience groups to improve the disaster avoidance and response capabilities of people in high-risk areas.
4. Promote the comprehensive application of emerging technologies
Promote the application of 5G, remote sensing, microwave, Internet of Things, edge computing and other technologies in early warning, realize cloud-side linkage early warning, realize remote automatic monitoring and early warning of rainstorm chain disasters, and fully ensure timely warning of on-site disasters in the event of power outages, network outages, and power outages caused by disasters.
(4) Enhance joint and collaborative response capabilities
1. Establish a unified command organization for emergency scenarios
Based on the urban flood control and drought relief headquarters, a unified command organization should be built to deal with heavy rain disasters in megacities, avoid the response chaos and the formation of information islands caused by "multiple commands", and comprehensively improve the comprehensive ability of megacities to jointly resist disasters.
2. Realize the interoperability and sharing of multi-department scheduling instructions
Based on the construction of a unified command organization, the interoperability, sharing and integrated push of multi-departmental dispatching instructions are fully implemented, which is convenient for all kinds of government agencies involved in dispatching to understand the disaster situation in an all-round way on the one hand, and convenient for grassroots personnel and rescue teams to obtain multi-dimensional integrated dispatching and command information on the other hand.
3. Multi-dimensional comprehensive research and judgment analysis and sharing of results
Through the aggregation of multi-department monitoring information and the sharing of dispatching instructions, comprehensive research and judgment analysis results can be produced from multiple dimensions, and relevant results can provide support to different departments from multiple aspects such as disaster development, risk research and judgment, early warning issuance, and team matching, so as to vigorously promote the co-construction and sharing of intelligent analysis and judgment capabilities, and improve the response capability of the whole chain of disaster response.
4. Promote the coordination and cooperation of multiple departments in actual combat rescue
KONE applies the "Digital Battlefield" and other fully interconnected and shared on-site team collaborative command and dispatch systems to unify the firefighting, public security, medical, local people and other teams at the disaster rescue site to maximize the coordination between grassroots teams in different departments.
(5) Enhance the ability of accurate rescue in actual combat
1. Accurate analysis of disaster-bearing areas
Combined with the results of simulation and deduction, the disaster bearing area and the changes in the disaster situation of the rainstorm chain disaster were accurately analyzed, so as to provide reliable support for the issuance of rescue orders and the advance preparation of relevant teams.
2. Real-time synchronization of deduction results
The results of the deduction simulation should be pushed to the integrated command and dispatch organization and the grassroots rescue team as needed. The overall disaster development trend should be handed over to the command and dispatch organization, so as to facilitate the unified allocation of resources to cope with the complex and changeable comprehensive situation. Relatively accurate and specific changes in the disaster situation should be sent to the grassroots rescue team to improve the rescue efficiency.
3. Dynamically improve rescue efficiency
Combined with the results of simulation and deduction, the next development trend of the disaster can be continuously analyzed and pushed. At the same time, it also provides a foundation for the grassroots rescue team to carry out dynamic rescue work combining "prevention and resistance". The rescue team can combine its own main rescue tasks and the next development trend of the disaster, and on the basis of ensuring the completion of the rescue tasks, according to the dynamic requirements of the headquarters, they can devote themselves to other flood drainage and flood control work as soon as possible to improve the rescue efficiency.
4. Accurate matching of disaster relief resources
The unified headquarters needs to take into account the overall development trend of the disaster, and reasonably arrange all kinds of disaster relief materials and disaster relief teams to go to the corresponding emergency scene. Maximize the use of all kinds of emergency rescue and disaster relief resources to achieve accurate matching of personnel and materials.
Combined with the comprehensive capacity building suggestions in various aspects, it can effectively improve the comprehensive application level of combining traditional planning, response, rescue and monitoring, deduction, and rescue systems in megacities in the face of heavy rain disasters. Effectively improve the support and guarantee capacity of intelligent technology in the comprehensive response to the rainstorm disaster chain in megacities, and provide a starting point for reducing the loss of people's lives and property.
Note: The presentation of the content of this article has been slightly adjusted, if necessary, you can view the original article.
Note: The paper reflects the progress of research results and does not represent the views of Chinese Journal of Engineering Science.