Taiwan suffers major floods almost every year due to typhoons and the seasonal "Mei-yu," and flooding exacts huge economic and social costs. If flooding potential can be determined in the very early stage, this will facilitate reduction of deaths, injuries, and economic losses. The Taiwan Typhoon and Flood Research Institute (TTFRI), National Applied Research Laboratories (NARLabs) has employed the technical capabilities of relevant agencies in the successful development of the "TAPEX Expert System-Flooding Potential Quick Look System," which can forecast the probability of flooding in the next 72 hours at township level when torrential rain is approaching. This system has been applied to Pingtung County, where it has achieved an average accuracy of over 80%. The system can allow relevant government units to mobilize at least 48 hours sooner than they could have previously, ensuring that losses of life and property can be effectively reduced.
Extreme weather, severe flooding
Due to the difficulty of accurately forecasting rainfall, most current early warnings of flooding are ba
Working behind the scenes to predict the future
Why are advance preventive efforts so important? According to statistics, each dollar spent on prevention can reduce disaster losses by 3.6 dollars. Taiwan suffers an average of NT$17.4 billion in losses from natural disasters annually. Therefore an appropriate level of preventive measures can reduce losses to approximately NT$1.7-NT$5.2 billion each year. Drawing on the capabilities of eight research and service units, TTFRI assembled a team containing several researchers and spent three and a half years developing the "TAPEX Expert System-Flooding Potential Quick Look System," which can forecast the probable times of flooding in the next 72 hours at township level. It extends the lead time for people to take actions to reduce damage to property and the risk to life.
The TAPEX expert system-flooding potential quick look system employs 72-hour rainfall forecasts from the Taiwan Cooperative Precipitation Ensemble Forecast Experiment (TAPEX), flooding potential maps and historical flooding records from the Water Resources Agency (WRA), MOEA, storm sewage system design standards from the Architecture and Building Research Institute, Ministry of Interior, and local flooding survey data.
A micro-genetic algorithm has been used to develop a fast assessment technique for flooding potential in urban areas, which has enhanced the efficiency and accuracy of flooding forecasts. Responding to the aforementioned characteristics, the system can perform customized correction and revision reflecting topography and localized causes of flooding.
The system has been applied on a trial basis taking Pingtung County as a demonstration area. Apart from forecasting the probability of flooding, the system can also analyze the most likely (high potential) and least likely (low potential) flooding areas. In consequence, that is the top priority that emergency actions should go to the areas with high potential for flooding. Trial results obtained in three past incidents (Typhoon Fanapi in 2010, Typhoon Nanmadol in 2011, and Typhoon Tembin in 2012) indicate that the system's average accuracy exceeds 80%, and it can enable relevant service agencies to mobilize at least 48 hours sooner than they would previously.
Active steps to safeguard the homeland
The Pingtung County assessment system now is online and has assessed possible flooding areas at township level four times a day, regardless of whether the weather is fair or rainy. The system transmits its up-to-date assessment results in real time to the county government and agencies, where the information is used to guide disaster prevention and relief decisions.
In the future, the NARLabs will continue to cooperate with the WRA, local city and county governments, and other relevant agencies in improving flooding assessment technology, and will use active techniques to ensure that the public can obtain flood and response information at the earliest possible time. TTFRI's behind-the-scenes efforts are winning valuable time in the fight against flooding. The TAPEX expert system-flooding potential quick look system is a powerful tool that can extend response lead time to protect the homeland from the ravages of catastrophic flooding!
Note: TAPEX (Taiwan Cooperative Precipitation Ensemble Forecast Experiment) is a platform for researching and testing rainfall forecasting technologies, and was jointly developed by the National Applied Research Laboratories (TTFRI, National Science and Technology Center for Disaster Reduction, and National Center for High-Performance Computing) in conjunction with the Central Weather Bureau and academic researchers.
