FloodsNew tool could help predict, prevent surging waters in flood plains

A group of international scientists studying China’s Yellow River has created a new tool that could help officials better predict and prevent its all-too-frequent floods, which threaten as many as eighty million people.

The tool — a formula to calculate sediment transport — may also be applied to studying the sustainability of eroding coastlines worldwide.

“Understanding the flow of sediment in rivers is important to the large number of people around the world who live near these waterways,” said Judy Skog, a program director for the National Science Foundation’s (NSF) Coastal SEES (Science, Engineering and Education for Sustainability) program, which funded the research.

Coastal SEES is largely supported by NSF’s Geosciences Directorate, with additional funding from the directorates for Biological Sciences, Engineering, and Social, Behavioral & Economic Sciences.

“This study will lead to better predictions of when and where rivers transport sediment, and to an understanding of how that sediment flow is affected by conservation and management efforts, such as the removal of dams,” Skog said.

The NSF notes that the Yellow River, known in Chinese as the Huanghe, is considered the cradle of Chinese civilization, and is often called the “mother of China” for its nutrient-rich sediment, which benefits farmland along its banks. But its floods, which led to some of the deadliest natural disasters in recorded history, have also earned it the name “China’s sorrow.”

Fertile nurturer, wanton killer
Each of the river’s identities — as the fertile nurturer and the wanton killer — derives from the same feature: the 1 billion tons of sediment that washes down each year from the Loess Plateau to the Bohai Sea. This huge sediment load can clog the river. When this happens, it not only floods but can change course.

“The Huanghe is probably the most studied fine-grained river in the world,” said Rice University sedimentologist Jeffrey Nittrouer, a primary author of a new paper about the Yellow River that appears online this week in the journal Science Advances.

“Despite that, the typical formulas and relationships that are used to describe sediment flux in most other rivers don’t work for the Huanghe,” Nittrouer said. “They consistently under-predict the sediment load of the river by a factor of 20.”

Nittrouer and lead paper author Hongbo Ma, also of Rice University, took sediment samples and created a 3-D map of the river bottom to create what they call a “universal sediment transport formula.” The formula is the first physics-based sediment transport model