Climate change raises stakes for Upper Midwest in the US

Grand Forks Herald: Gabriel Carter joined the sandbag brigade in the Fargodome this spring and helped build an earthen dike to protect a relative’s home in the flood-prone Oakport neighborhood north of Moorhead. While he was stooping, shoveling and maneuvering a loader during the Red River flood fight, the North Dakota State University student made a connection not all are apt to reach. “This is what climate change looks like,” he says. “It’s definitely a consideration that I make.”

…Will Gosnold, a geophysicist at the University of North Dakota who has studied climate change for more than 20 years, says flood protection plans should take the implications of more frequent and extreme floods into account. He co-authored a study published in 2000, in the aftermath of the devastating 1997 Grand Forks, N.D., flood, that stated flood protection plans must more accurately reflect climate cycles and land-use changes, including field drainage.

Flood mitigation takes its cues from flood predictions, which average river levels over recorded history. That tends to understate the tendency for catastrophic floods during wet periods, Gosnold and his UND colleagues argue. Thus with the wetter cycles that are expected to recur from global warming, the Red River Valley is likely to face more floods of the magnitude of 2009 and 1997, which echo epic ancient, or “paleo,” floods.

“We face a dilemma in that our flood mitigation program is based on floods that do not cause much damage and ignores the floods (paleo floods and other extreme floods) that cause the vast majority of damage,” wrote Gosnold and his co-authors….

The Sorlie Bridge between Grand Forks, North Dakota, and East Grand Forks, Minnesota, during the 1997 Red River flood, USGS