Potentially more effective flood mitigation techniques than dams

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University of Iowa graduate student Federico Antolini suggests that small reservoirs like ponds may mitigate flooding better than dams.

Cecilia Shearon

Flood mitigation and climate change researcher Federico Antolini, who is currently pursuing his doctorate in geoinformatics, poses for a portrait near the Iowa River on Monday, November 1, 2021.


Traditional flood mitigation techniques, like dams, are not effective against the increased flooding that climate change will cause, according to research from the University of Iowa.

A study by UI graduate student Federico Antolini pointed out that flood mitigation could be the most beneficial in controlling future flooding, depending on where the mitigation elements are placed.

According to National Agroforestry Center, flood mitigation is an area of ​​the floodplain that is sometimes allowed to be flooded from a river or stream – of which ponds are an example.

Antolini proposed that the establishment of ponds in strategic and different areas of the stream or river would slow the rate of rainfall runoff by making it downstream.

“The problem is that the water is coming into the stream too quickly and creating the flood,” Antolini said.

Gabriele Villarini, director of the Iowa Institute for Hydraulic Research and professor of civil engineering at UI, conducted research that found that climate change, especially greenhouse gases, is causing more flooding.

“The data supports the idea that the frequency of flooding has increased over the past decades,” Villarini said.

Antolini said that due to increased flooding, dams break down to control the water as they were designed.

“We know that large reservoirs like the Coralville Dam are working – it failed in 2008, but generally they are working,” Antolini said. “However, the climate is changing and they probably won’t work in the future.”

Eric Tate, IU associate professor of geographic sciences and sustainability, said dams were already failing across the country.

“There are all kinds of problems with large dams and we are seeing a movement, especially in the United States, to bring down dams because of the ecological damage they cause and their lifespan is limited,” he said. Tate said.

Tate said smaller reservoirs scattered across the floodplain would store some water, as opposed to a massive amount of water in one place. This could reduce the number of large floods seen more frequently in recent decades, he said.

“I think these little methods of distribution are going to be more important than ever,” Tate said.

Antolini said ponds and dams work the same way as traffic jams.

“Like traffic, you have a traffic jam when people are all leaving at the same time,” Antolini said. “If people were to leave at five, six and seven, there is still traffic, but you won’t be stranded. “

Antolini said the benefit of installing small ponds is not limited to flood mitigation – it also provides positive ecological and economic results.

Ponds allow vegetation and native species to grow in a healthy and safe environment. Vegetation around the ponds also helps clean up the water flowing through them, he said.

Dams require a lot of maintenance, he said, while ponds only have an upfront cost to install them, but require very little maintenance once established.

Antolini said flooding is not inherently bad as it benefits the health of the stream in many ways. Flooding becomes severe when water affects people and seeps into the built environment, he said.

“We can’t control nature,” he said, “but we can adapt to it. “


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