Thursday , October 21 2021

Fluvial geomorphology of mountain streams helps to understand the dynamics of other rivers such as Cuyahoga


River sediment talks about climate change

Visiting professor and researcher at Case Western Reserve University, Nicholas Sutfin, crossed St. Vrain Creek, a 32-mile-long tributary of the South Platte River in north-central Colorado. Credit: Nicholas Sutfin

Studying the sediment of a mountain river can reveal thousands of years or more of the history of a waterway, including new threats from more frequent forest fires and increased precipitation brought on by climate change.

And understanding these challenges can provide information on other waterways, including the Cuyahoga River.

These climate-induced threats are among the findings recently published in the journal Communications of nature by Nicholas Sutfin, Visiting Assistant Professor of Earth, Environmental and Planetary Sciences at Case Western Reserve University. Sutfin is a fluvial geomorphologist – a scientist who studies how rivers interact with the surrounding relief forms, especially in relation to sediment movement.

Sutfin has so far focused on the creeks of the Front Range of the Rocky Mountains where he conducted research as an extension of his Ph.D. dissertation with mentor and co-author Ellen Wohl, Colorado Distinguished Professor.

These high-rise mountain streams have often been seen as erosion machines, eroding the surrounding landscape. But they also retain sediments along their bottoms and banks for hundreds and sometimes thousands of years; and the larger the flow, the older the sedimentary record.

But this old story is being disturbed more often. Among Sutfin and Wohl's recent findings is that three trends in "alluvial plain disturbance" – forest type, precipitation patterns, and frequency and intensity of forest fires – must change under a changing climate.

"There will definitely be an influence of climate change," Sutfin said. "The snow bundle slows and melts much earlier, more flooding is likely and larger forest fires are becoming more common, and now the sediments are likely to wear out faster."

Forest fires in particular may be responsible for reducing how long the sediment remains in place because a fire can take the land out of its ability to filter water slowly and efficiently, Sutfin said. Instead, the water from the surface of the rain simply runs into the river.

As it applies to Cuyahoga, other rivers

Sutfin's work could help inform a broader and more universal understanding of rivers. This includes massive systems like the Mississippi, for more localized rivers, like the Cuyahoga.

Suftin is also a native of northeastern Ohio with a keen interest not only in the Cuyahoga but also in the Chagrin and Black Rivers (the latter of which flows through its Lorain County).

"Urban rivers are generally poorly studied," he said. "The increase in frequency and intensity of major storms is true here in northeastern Ohio as well as in the Rocky Mountains."

Even the effects of fire on the landscape and river flow can be applied to understand the development and use of land around urban streams, he said.

"When a site is burned by forest fires, the effect is similar to what happens with urbanization, when we pave the earth with waterproof surfaces," Sutfin said. "Then the rain goes straight into the river, causing more flow, more erosion and more sediment movement – so the parallels are evident."

New insight into the flow of rivers and transport of sediments under ice cover

Provided by
Case Western Reserve University

The fluvial geomorphology of mountain streams helps to understand the dynamics of other rivers such as Cuyahoga (2019, June 11)
recovered on June 11, 2019

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