Need to strengthen flood resilience to better protect people

Understanding and dealing with the consequences of both natural and human-induced disasters are important to ensure people's safety and minimize economic losses, especially in countries such as China that have been battered by massive floods in recent years.

In the coming week, the water authorities forecast that due to heavy rainfall, some regions in the basins of the Haihe River, Yellow River, Yangtze River, Pearl River, and Liao River may experience flooding. The flood prevention situation remains severe and complex. The water conservancy department is further strengthening flood defense during this critical flood prevention period.

The increasing frequency of heavy downpours and severe floods shows that more and more regions are becoming vulnerable to extreme weather events, highlighting the urgent need to strengthen disaster preparedness and boost climate resilience.

Accurately forecasting heavy rains and floods involves analyzing past data and studying the weather patterns. Historically, provinces and regions such as Henan, Sichuan, Jiangxi and Hunan, and Beijing have become increasingly vulnerable to severe flooding. The frequency and intensity of floods are increasing, driven by climate change, so more extreme weather events with potentially more devastating impacts are expected in these areas in the coming years.

Recognizing these challenges, the Chinese government has been taking measures to strengthen its disaster preparedness. In his speeches and policy initiatives, the top Chinese leader has been stressing the importance of improving infrastructure and the disaster-response mechanism. Such ideas, as reflected in the 14th Five-Year Plan (2021-25), include strengthening flood-control infrastructure and improving advanced hydrological monitoring systems. Additionally, the "sponge city" initiative aims to enhance urban climate resilience by improving water absorption and reducing runoff. These policies lay a strong foundation for combating climate change and improving disaster preparedness.

But despite its significant and sincere efforts, China needs to do more to boost its flood resilience. For example, by incorporating advanced hydrological models and machine learning algorithms into its action plan, China can improve flood forecasts and the early warning system. These technologies can help analyze huge amounts of data to predict massive floods more accurately and issue early warnings, which can save lives and reduce economic losses.

However, these technologies have some limitations, because they have to be supported by comprehensive urban planning, flood-proof infrastructure, improved drainage systems and restoration of natural water bodies to absorb excess water. For instance, real-time data from sensors placed in rivers and weather stations can feed into predictive models, allowing the authorities to make timely decisions on evacuations and resource deployment.

Comprehensive urban planning is a critical aspect of flood resilience. Cities must be designed or retrofitted to manage floodwaters by, among other things, including constructing flood-proof infrastructure such as elevated buildings and flood barriers, and improving the drainage system.

In addition, restoring natural water bodies and wetlands can act as buffers, absorbing excess water and reducing the impact of floods on urban areas. These natural solutions are cost-effective and provide environmental benefits such as habitat creation and water purification.

Sustainable groundwater management, too, is essential, because over-extraction of groundwater can exacerbate flooding — by reducing the soil's ability to absorb water. Methods to increase the groundwater level, such as by creating permeable surfaces in urban areas and building "rain gardens", can help mitigate flood risks. Such measures allow rainwater to percolate into the ground, replenishing aquifers and reducing surface runoff.

According to our (University of Science and Technology Beijing) research, imbalances in the underground water table cause severe land subsidence, particularly in metropolitan areas such as Beijing. That's why the North-South Water Diversion Project, one of China's most innovative and ambitious initiatives designed to reduce water shortage by increasing the groundwater level in the northern region, including Beijing, Tianjin and Hebei, is so important.

Developing upstream reservoirs and better water diversion projects can also help reduce flooding and better protect urban areas against floods. Reservoirs can store excess water during heavy rainfall, releasing it gradually to prevent downstream flooding. Water diversion projects, such as channels and tunnels, can redirect floodwaters away from vulnerable areas. These infrastructure projects require significant investment but can provide long-term protection against floods.

Meteorologists and climate scientists have said during the rest of this year more extreme weather could affect regions across China, including Beijing. The rising threat of more severe floods highlights the need to take immediate climate action including boosting disaster preparedness. By establishing advanced forecasting systems, strengthening sustainable groundwater management, and making urban infrastructure more resilient, the government can better protect the people and infrastructure from future floods.

It is critical therefore that everyone — from policymakers to ordinary citizens — works together and prepare for the challenges ahead. The safety and well-being of the Chinese people, and people in the rest of the world, depend on collective efforts to address the common global challenges such as climate change.

Majid Khan is an associate professor at the School of Civil and Resources Engineering, University of Science and Technology Beijing, and a researcher in disaster prediction and prevention and seismic activities; and Dazhao Song is a professor at the School of Civil and Resources Engineering, University of Science and Technology Beijing, and a researcher in dynamic disasters prediction and prevention technologies.The views don't necessarily reflect those of China Daily.

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