Water Resources Departments Take Multiple Measures to Respond to Flood Conditions: Focus Closely on Key Links and Implement Detailed Flood Control Measures

　　On April 1 this year, China entered its flood season. According to forecasts by the Ministry of Water Resources, from June to August this year, China may experience concurrent droughts and floods, with floods outweighing droughts, and all seven major river basins may experience rainstorm floods of varying degrees. Water resources departments are focusing closely on key areas such as the defense against floods in small and medium-sized rivers and mountain torrent disasters, improving the construction of flood control engineering systems, enhancing the flood control and disaster reduction capacity of small and medium-sized rivers, using new technologies to improve forecast accuracy, and implementing detailed flood control measures.

　　At present, China is successively entering its flood season from south to north. According to forecasts by the Ministry of Water Resources, during this year's flood season China will experience concurrent droughts and floods, with floods outweighing droughts. As the main flood season approaches, flood control pressure on major rivers and large lakes is increasing, and high-intensity, short-duration heavy rainfall occurs from time to time in some areas. Safe flood passage of small reservoirs and the defense against floods in small and medium-sized rivers and mountain torrent disasters must be given high priority, and flood control work has entered a critical stage.

　　What are the characteristics of the flood situation?

　　Numbered floods in major rivers occur early

　　On April 1 this year, China entered its flood season. Over the nearly two months since the start of the flood season, what characteristics has the flood situation shown compared with the same period in previous years? How will it develop next?

　　"Overall, affected by the El Niño event and other factors, from June to August this year, China may experience concurrent droughts and floods, with floods outweighing droughts. It is predicted that all seven major river basins in China may experience rainstorm floods of varying degrees," said Yin Zhijie, chief hydrological forecaster of the Ministry of Water Resources.

　　"This year, numbered floods in major rivers occurred early and were large in magnitude," said Li Chenliang, head of the Fourth Flood Control Division of the Flood and Drought Disaster Prevention Department of the Ministry of Water Resources. Since the start of the flood season, the Beijiang, Hanjiang and Dongjiang rivers in the Pearl River Basin have experienced a total of six numbered floods. The No. 1 flood of 2024 on the Beijiang River was the first numbered flood on a major river in China this year and the earliest numbered flood on a major river nationwide since statistics began in 1998; the No. 2 flood of 2024 on the Beijiang River occurred two months earlier than the catastrophic Beijiang flood of June 2022 and was the earliest catastrophic flood on a major river since statistical records began.

　　Currently, the "Dragon Boat Water" period is underway. Xu Shuang, director of the Flood and Drought Disaster Prevention Division of the Pearl River Water Resources Commission, said that this year's "Dragon Boat Water" impact is expected to be relatively heavy, and floods may still occur on the Xijiang, Beijiang, Dongjiang and Hanjiang rivers in the Pearl River Basin.

　　This year, the Yangtze River Basin will see floods outweighing droughts, with droughts and floods coexisting. During the main flood season (June-August), precipitation in the Yangtze River Basin will be higher than the same period in normal years, with the upper reaches of the Yangtze normal to above normal, the middle and lower reaches above normal, and areas near the middle reaches' main stream possibly more than 20 percent above normal. A relevant official of the Yangtze River Water Resources Commission said that the controlled reservoir group in the basin was drawn down in an orderly manner earlier, and the overall flood situation in the basin is stable, but there have still been several heavy rainfall processes recently, so the vigilance for flood and drought disaster prevention must remain high.

　　During this year's flood season, rainfall in the middle and lower reaches of the Yellow River Basin will be 20 to 30 percent higher than the same period in normal years. Floods may occur on the main stream and on tributaries such as the Yiluo, Qin, Fen and Dawen rivers, and periodic droughts may occur in the upper reaches.

　　"According to medium- and long-term climate trend forecasts, during this year's flood season precipitation in the Huai River Basin will be above normal, with the middle and upper reaches of the Huai River and areas to the south, the upper reaches of the Hongru River, and the middle and lower reaches of the Ying River more than 50 percent above normal. We will closely monitor weather changes and the development of rainfall and water conditions, and do a good job in all flood control and preparation work," said He Qi, director of the Flood and Drought Disaster Prevention Division of the Huai River Water Resources Commission.

　　In addition, floods may occur on the rivers of the Hai River Basin; on the Nenjiang, Songhua, Liao and Heilong rivers in the Songliao Basin; on Taihu Lake; and on the Qiantang and Min rivers.

　What are the key areas of prevention?

　　Consolidate the flood control engineering system and focus closely on key areas such as the defense against floods in small and medium-sized rivers and mountain torrent disasters

　　The Beijiang River winds through the land of southern Guangdong, where rivers large and small converge. The roughly 64-kilometer-long Beijiang Grand Dike protects more than 32 million people in Guangzhou, Foshan and Qingyuan in Guangdong.

　　At the end of April, the No. 2 flood of 2024 occurred on the Beijiang River. "Facing a flood of huge volume and rapid flow, the main dike of the Beijiang River played an important role," said Zeng Jinhong, director of the Flood Control and Engineering Construction Management Department of the Guangdong Beijiang River Basin Administration. At the peak, more than 2,700 people patrolled the dike, reinforcing the dike foundation and body by means such as filling sand to suppress seepage, heightening and thickening, and filling ponds to consolidate the foundation.

　　At present, a flood control engineering system centered on the Beijiang Grand Dike has taken shape in the middle and lower reaches of the Beijiang River, providing a more solid guarantee against floods. Zeng Jinhong said that the Beijiang Grand Dike retains water, the Feilaixia Water Conservancy Project intercepts floods and cuts peaks, the Pajiang Flood Storage and Detention Area detains floodwater, and the Lubao and Xinan waterways divert floodwater; the flood control projects cooperate scientifically and comprehensively use means such as storage, detention, discharge and diversion to enhance flood control capacity.

　　At present, China has built a basin flood control engineering system based mainly on reservoirs, river channels and dikes, and flood storage and detention areas. About 34,000 kilometers of dikes have been built in the Yangtze River Basin, and more than 50,000 reservoirs have been constructed, with a total storage capacity of about 400 billion cubic meters; the reconstruction project of the Yellow River diversion sluice gates in the lower reaches and the "14th Five-Year Plan" flood control project in the lower reaches of the Yellow River are being accelerated; and the second phase of the Huai River seaward waterway project is under orderly construction, which will solve the problem of poor flood discharge in the lower reaches of the Huai River.

　　"A sound flood control engineering system is an important guarantee against floods. On the one hand, we will continue to scientifically plan the construction of reservoirs, river channels, dikes and flood storage and detention areas to comprehensively enhance the basin's disaster prevention and reduction capacity; on the other hand, we will seize the window period to strengthen patrols and duty at key parts such as reservoir dams, spillways, dangerous sections of dikes, and structures crossing dikes," Li Chenliang said.

　　Small and medium-sized rivers are a focus of flood control and also a weak link. How can the shortcomings be addressed? Li Chenliang said that small and medium-sized rivers generally have basin areas of 200 to 3,000 square kilometers and are numerous and widely distributed; small and medium-sized rivers, especially those in mountainous areas, have rapid confluence and sharp rises and falls. Water resources departments are continuously improving flood control contingency plans for small and medium-sized rivers, carrying out river channel dredging, dike construction and reinforcement of water conservancy projects to enhance the flood control and disaster reduction capacity of small and medium-sized rivers.

　　Mountain torrent disasters are sudden and highly destructive. How can they be prevented before they occur? Handan in Hebei, located in the transition zone from the Taihang Mountains to the North China Plain, has short and fast-flowing rivers, and the city's mountain torrent disaster prevention and control area totals 2,973 square kilometers. Du Manhong, deputy director of the Office of the Handan Flood Control and Drought Relief Headquarters, said: "We have comprehensively investigated the baseline, identified risk points for mountain torrent disasters, and improved the 'call-and-response' mechanism for pre-disaster warnings. Once rainfall reaches a dangerous level, warning information will reach the grassroots flood control frontline directly, and emergency plans will be activated in a timely manner to evacuate residents."

　　Since the beginning of this year, water resources departments have adhered to combining engineering and non-engineering measures, comprehensively investigated hidden mountain torrent risks, and advanced flood control management of mountain torrent gullies; they have accelerated the construction of the "three lines of defense" for mountain torrent disaster rainfall and water condition monitoring and forecasting, consisting of rain-measuring radars, rain gauge stations and on-site monitoring and warning equipment, achieving full coverage of forecasting and warning.

　　What new measures are there for flood control?

　　Accelerate the use of new technologies and improve the accuracy of forecasting and warning

　　Information from monitoring points everywhere flows continuously into the flood control center platform. In Liaocheng, Shandong, the "digital water conservancy one map" makes flood control work clear at a glance.

　　On the mobile app, users can query engineering conditions, rainfall conditions and water conditions, receive warning information, and conduct video connections with the flood control headquarters, achieving information sharing and rapid response. "The technology chain and the flood control work chain are closely linked, and big data 'runs' ahead of floods, enabling rapid release of forecasting and warning information," said Han Gang, deputy director of the Liaocheng Water Resources Bureau.

　　Digital empowerment of flood forecasting and warning. On May 21, the first rain-measuring radar at the Datengxia Water Conservancy Project was completed and put into use, taking only two months from site selection to commissioning. By before the flood season of 2025, all three rain-measuring radars at the Datengxia Water Conservancy Project will be completed and operate as a network, providing more reliable rainfall and water condition monitoring and forecasting information and supporting scientific and precise dispatching of the Datengxia Water Conservancy Project.

　　Yin Zhijie said that this year water resources departments will continue to strengthen the construction of rain-measuring radars, rain gauge stations and hydrological station networks to efficiently and accurately obtain data such as rainfall and water conditions and enhance monitoring and reporting perception capabilities; they will promote model research and development, continuously correct and calibrate model parameters, and achieve an effective unity of extending the flood forecast lead time and improving flood forecast accuracy.

　　The construction of digital twin water conservancy makes flood control decisions more scientific. At present, the national first-level data base plate with a data volume of petabyte (PB) level has been completed, and breakthroughs have been made in the application of the "four forecasts" (forecasting, warning, rehearsal and contingency plans) in basin flood control operations. The national rainfall outlook period has been extended from 20 days to 30 days, and the forecast accuracy for major rivers during key periods has reached more than 90 percent. The Ministry of Water Resources will continue to strengthen the deep integration of modern information technology with flood control work, taking basins as units, integrating information technology, and implementing scientific and precise dispatching of the flood control engineering system with "one unit of flow, one unit of reservoir capacity, one centimeter of water level."