Prevention against flash floods has become a prominent issue and weak link in the current work of food control and mitigation. This solution is to establish county-level non-structural measure systems that concentrated on small watershed with an area less than 200 km2.
Office of State Flood Control and Drought Relief Headquarters (SFDH); China Institute of Water Resources and Hydropower Research (IWHR), Ministry of Water Resources of the People’s Republic of China
flash flood disaster, non-structural measures, monitoring, warning, community-based defense system
Prevention against flash floods has become a prominent issue and weak link in the current work of food control and mitigation. This solution is to establish county-level non-structural measure systems that concentrated on small watershed with an area less than 200 km2. (1) Flash flood survey. Investigate the natural, social and economic situation of all small watersheds. (2) Risk assessment and risk area delineation. Based on the investigation result, define hazardous area and safety area within the flash flood disaster risk area. (3) Determination of preparedness parameters and their magnitudes, such as critical rainfall and water level. (4) Construction of monitoring system including automatic rainfall and water level monitoring instruments, simple rainfall and water level measurement devices used by local residents. (5) Construction of warning system platform at county level. The platform has the functions of basic information inquiry, monitoring hydrological data inquiry, hydrological forecasting, warning message dissemination and system management. (6) Equip with necessary warning facilities. In addition to traditional ways such as hand cranking alarm, gong and whistle, warning facilities also included telephone, fax, text message, radio broadcast and television, etc. (7) Establish a community-based defense system for disaster prevention in which the monitoring and prevention activities were enforced by the residents themselves. Set up the five hierarchy responsibility system that covers the level of county, town, village, group and household. (8) Formulate the prevention plan of flash flood disaster in accordance with the Compilation Guideline for the Flash Flood Disaster Prevention Plan issued by the SFDH. Carry out knowledge dissemination, training and exercise activities. The implementation of the solution will effectively improve the residents’ capability of withstanding risks, and greatly reduce casualty and property losses in mountainous regions.
This solution is to establish county-level non-structural measure systems that concentrated on small watershed with an area less than 200 km2. The investment for each county was 6 million RMB in average, shared by the central government and local government.
In 2005, the Ministry of Water Resources, together with the Ministry of Land and Resources, China Meteorological Administration, the former Ministry of Construction and the former State Environmental Administration, compiled the first National Flash Flood Control Planning (NFFCP). In 2006, the State Council officially approved the NFFCP. In 2009 the Chinese government set special funds in the budget for pilot practice of non-structural measures on flash flood disaster prevention in 103 counties of 30 provinces. In 2010 the Ministry of Water Resources, together with the Ministry of Finance, the Ministry of Land and Resources and China Meteorological Administrative, organized conference to officially initiate the program of non-structural measures for flash flood disaster prevention at county level nationwide. It was planned to initially establish a non-structural measure system of disaster prevention within 3 years which mainly focuses on the monitoring and warning in 1836 counties.
In order to reduce the impacts of flash flood disasters, the following problems are to be solved: (1) How to carry out investigation and assessment including natural, social and economic situation, to define hazardous and safety area, to identify the people within the hazardous area; (2) How to improve the forecast and warning of flash floods. It is needed to take in-time warning opportunities to realize the purposes of accurate preparedness, emergent evacuation and timely recovery; (3) How to improve the risk awareness and emergency response abilities of the affected groups in risky areas. It is required to enhance the awareness of the residents in flash flood prone areas and to improve their capacities to get rid of disasters; (4) How to improve the establishment of emergency preparedness plans referring to flash food disasters. The preparedness plan should be reasonably predictive, operational and can be effectively implemented that takes all stakeholders in consideration.
Currently, the projects developed in 2010 are in full implementation throughout the country. The projects developed in 2011 will be finished before the flood season in 2012. In this year, Hunan Province, Yunnan Province, Jiangxi Province and Hubei Province timely distributed warning information by using non-structural measures system recently when fighting against flash flood disaster. The residents were evacuated in advance, and significant benefits were achieved. For example, on 23rd August, the forest area of Shennongjia, Hubei Province was hit by heavy rainstorm. With 3-hour rainfall exceeding 100mm, total rainfall was 270mm, being the maximum of the past 58 years. 3 hours later, the flood control department instantly sent the warning information using the platform, and related residents were evacuated in advance. No person was injured or died. The system of non-structural measures on flash flood disaster prevention has become a real “umbrella for life protection”.
One indicator is whether the implementation of the solution can effectively improve the residents’ capability of withstanding risks, and greatly reduce casualty and property losses in mountainous regions. The other indicator is whether the monitoring and warning system can be effectively operated and reliably maintained.
Against the backdrop of economic development and climate change, disasters caused by flash flood in mountainous regions have been increasingly serious, taking its toll on people and properties. According to statistics, the death toll created by flash floods takes up as high as 80% of that created by all flooding disasters. Prevention against flash floods has become a prominent issue and weak link in the current work of food control and mitigation. This resolution has broad prospect of application in regions prone to flash floods. By replicating this kind of flash flood monitoring and warning system, the relevant regions could suffer less from disaster damages and could build up their risk resistance capacity. The administrative mechanism for the system shall be established in line with the specific local political systems, which is an important precondition for the flexible application of this system.
The key lessons could be summed up in the following four aspects:
(1) a full-scale responsibility system should be established with disaster prevention responsibilities being specifically designated to every position of each level of government from the central to the very local authorities. Grass-root units are the frontline and the crucial point of flash flood prevention. Only when the work at the grass-root units are soundly implemented, could the commands become timely and effective and the mass casualty be avoided. Therefore, what need to be especially stressed is the grass-root responsibility system at the county, township, village and group level;
(2) a scientific and comprehensive planning system should be compiled. Planning is the foundation for the effective shunning of flash flood. Flash flood prevention plan shall be applicable and in line with the local conditions based on massive investigations and research. The plan should clearly identify five aspects, namely the initiation process and information transmission methods for the warning, the subjects of emergency relocation, the safe escape routes and venue of shelters, logistic service and material supply, and the responsible person and team for the implementation of each piece of work.
(3) an all-round monitoring and warning system must be established. The monitoring and warning system is the extension of our eyes and ears for the prevention of flash floods, therefore it is very necessary to build the monitoring and warning systems centered around counties or cities. Efforts should be strengthened on three aspects. First, build up the information monitoring capacity. We should improve the real time monitoring of rainfall and floods by integrating the hydrological and meteorological data, establishing a real time rainfall monitoring system covering down to at least the township levels while trying the best to make sure the data are timely, precise and complete. Second, build an information publication platform. According to the severity of rainstorm and flood, the warning is divided into different grades. At the same time, the real time rainfall information and the warning message are to be sent to the responsible persons and the threatened people through group sending of text message, group calling, radio broadcast and repeating TV display. Third, enhancing the construction of warning facility at village level. The effective warning method and experience accumulated in the past shall be spread to all the villages prone to flash flood. (4) build a popularity, publicity and education system. One important reason for the massive casualty in case of flash flood is people’s shortage of knowledge on flash flood prevention, the lack of awareness and the deficiency of emergency commanding. Therefore, it is very important to boost the publicity and education and enhance the relevant awareness and capacity of the people in mountainous regions. The administrative departments shall provide the general public with free brochures and documents and carry out trainings and rehearsals prior to the flood season of each year. All the media shall frequently publicize the basic knowledge of disaster prevention and enhance people’s disaster awareness.
In 2005, the Ministry of Water Resources, together with the Ministry of Land and Resources, China Meteorological Administration, the former Ministry of Construction and the former State Environmental Administration, compiled the NFFCP. The planning adheres to the principle that non-structural measures are given as the priority while combining engineering measures. With the guidance of the principle, a disaster prevention system will be established integrating functions of monitoring, communication, forecasting and pre-warning.
In October 2006, the State Council officially approved the NFFCP and stipulated that with the short-term planning projects as the priority and timely personnel evacuation and casualty reduction as the objectives, the construction of pilot projects should be sped up in priority prevention area of flash flood disaster by adopting effective non-structural measures such as rainfall monitoring, construction of pre-warning system. On top of that, knowledge dissemination and management should be strengthened, the general public’s awareness on disaster prevention and mitigation should be improved, and the masses’ capacity on self-prevention, self-rescue and mutual assistance should be promoted to set up a monitoring and prevention system enforced by the residents themselves.
In 2009, 103 counties of 30 provinces (autonomous regions and municipalities) conducted pilot practices of non-structural measures on the flash flood disaster prevention. In 2010 and 2011, the central government issued 3.8 billion Yuan RMB subsidies to support the development of non-structural measures in 1100 counties.
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