Dr Iestyn Woolway, a NERC Independent Research Fellow at the School of Ocean Sciences, contributed to the study, which provides the first global, long-term assessment of how rivers connect with their floodplains. Recently recognised as a finalist in the prestigious Blavatnik Awards for Young Scientists, Dr Woolway鈥檚 involvement further highlights the international impact of his work.
The study, led by Professor Lian Feng from Wuhan University, analysed nearly four decades of data from 1984 to 2019, on essential processes influencing flooding, ecosystems, and water quality worldwide.
The research reveals that surface water connectivity between rivers and their floodplains has increased slightly on a global scale over the past 40 years, with an overall rise of around 3%.
However, this global trend masks significant regional differences.
Key findings
One of the key findings is that around 17% of rivers show consistent increases in connectivity, significantly more than the 11% experiencing continuous declines. The most notable increases were observed in eastern Asia and high-latitude regions, while widespread decreases were identified in arid and semi-arid regions, including parts of central North America, South America, and southern Asia.
Climate change is the main reason these changes are happening. More rainfall helps rivers spread out and connect with nearby land, while more evaporation dries things out and reduces that connection. Human activities鈥攍ike building dams, farming, and managing land鈥攁lso have an effect, but usually on a smaller, local scale. These actions can either help or harm how well rivers stay connected to the surrounding land, depending on how they are managed.
The study also finds a clear link between how connected rivers are to surrounding land and how much sediment they carry. When rivers are more connected to their floodplains, they move and spread more sediment. This matters because it affects the shape of rivers, how nutrients are distributed, and how carbon moves through the environment.
The importance of the research
These findings are significant because surface water connectivity is fundamental to how rivers function. It influences flood risk, ecosystem health, water quality, and sediment dynamics. By providing the first global observational benchmark, the research offers critical insight into how river systems are responding to climate change and increasing human pressures.
The findings are expected to inform future river management, conservation strategies, and climate adaptation planning worldwide.
Satellite data show that connections between rivers and their floodplains have increased globally over the past four decades, largely driven by climate change, with significant consequences for sediment transport, ecosystems, and flood risk.
Dr Iestyn Woolway said: 鈥淭his research provides the first clear global picture of how rivers and their floodplains are changing over time. The fact that climate change is already driving measurable shifts in connectivity underscores the urgency of developing more adaptive and sustainable approaches to river management.鈥