Liu Ruoqi, Dong Jinwei, Jiang Luguang, Ge Yong, Fan Chang, Yang Tong, Zhang Geli
Department of Land Resources, College of Land Science and Technology, China Agricultural University, Beijing 100193, China.
Key Laboratory for Resource Use and Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Proc Natl Acad Sci U S A. 2024 Sep 24;121(39):e2410967121. doi: 10.1073/pnas.2410967121. Epub 2024 Sep 16.
The "Returning Farmland to Lakes" (RFTL) project began in China following the catastrophic 1998 floods. It aims to recover flood storage capacity and mitigate flood risk to agriculture and people. This flood adaptation strategy divides the floodplain into three types of restoration polders with different flood control levels (double restoration polders, single restoration polders, and storage polders) and polders for intensive production and living (nonrestoration polders). During the substantial flooding in the Poyang Lake Basin in 2020, the double and single restoration polders were operated for flood diversion for the first time since 1999. This event provided an opportunity to assess the effectiveness of the RFTL project. Using satellite observations of rice planting and flooding areas, we found that 86% of paddy rice areas (3,400 km) in the basin were successfully protected due to the timely flood diversion into different levels of polders. Compared to 1998, the flooded rice areas decreased overall by 58% (18 to 92% in different types of polders). Thus, the RFTL project has enhanced regional agricultural resistance to floods. A more comprehensive assessment of the RFTL project, including other ecosystem services and functions, is necessary in the future for regional sustainable development.
“退田还湖”工程于1998年中国发生特大洪水后启动。其目的是恢复蓄洪能力，减轻洪水对农业和人民的威胁。这种洪水适应策略将洪泛区分为三种不同防洪水平的恢复圩区（双退圩区、单退圩区和蓄洪圩区）以及用于集约化生产和生活的圩区（不退圩区）。在2020年鄱阳湖流域发生严重洪水期间，双退和单退圩区自1999年以来首次用于分洪。这一事件为评估“退田还湖”工程的成效提供了契机。通过卫星对水稻种植和洪涝区域的观测，我们发现该流域86%的水稻种植面积（3400平方公里）因及时向不同级别的圩区分洪而得到成功保护。与1998年相比，被洪水淹没的水稻面积总体减少了58%（不同类型圩区减少幅度为18%至92%）。因此，“退田还湖”工程增强了区域农业的抗洪能力。未来有必要对“退田还湖”工程进行更全面的评估，包括其他生态系统服务和功能，以实现区域可持续发展。
