Ice Jam in the Green River Causes Concern Among Jamestown Residents

Ice Jam in the Green River Causes Concern Among Jamestown Residents

Photo by Junior Arguello

JAMESTOWN– An ice jam on the Green River out by Jamestown has caused flooding and freezing on several residents’ properties, causing concern and worry, and a water diversion structure installed in 2010 is being blamed.

According to Jamestown resident Jon Jasperson, several residents believe the diversion dam may not be completely at fault, but it is definitely partially to blame for the ice jam.

“You can’t say it’s 100 percent causing it, because things like this can happen, but I think it’s definitely contributing to it,” Jasperson said.

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Jasperson has lived in Jamestown for about 37 years, and his father has lived there since 1953, and neither of them can remember an ice jam ever being this bad.

He said the water elevation in front of the diversion dam is five to six feet higher than the water behind the dam, which he believes is causing several issues.

“We’ve seen a rise in water height and a lot more flooding since the dam went in,” he said.

Photo by Jon Jasperson

History of the Killdeer Wetland Diversion Structure

According to Mark Westenskow, Public Works Director for the City of Green River, the diversion structure was built in 2010 to provide a means of diverting river water into the Killdeer Wetlands to help revitalize that habitat.

“This project was recommended by the Bureau of Reclamation in 2000 and permitted by the Army Corps of Engineers in 2009 after efforts to revitalize the wetlands had been tried and failed in the past,” Westenskow said.

The structure was modified slightly in 2013.

Photo by Jon Jasperson

Ice Jams Occur Often at Both Natural and Man-Made River Features

During Westenskow’s time with the city since 2013, concerns of ice build up above the diversion structure have never been brought to his attention until now.

“Some ice has accumulated near the diversion structure, and it appears to have connected over the past week or so with ice that had been accumulating at other points along the river,” Westenskow said.

Photo by Jon Jasperson

According to Westenskow, ice jams can form in many circumstances, including at natural or man-made features in rivers. Ice accumulation can be found on riverbanks, near bridges, sharp riverbends, sandbars, or confluences.

As cold weather worsens and continues, the ice can build up, resulting in a jam.

“The Killdeer Wetland diversion structure is one man-made feature between the City of Green River and Jamestown, but there are other sand bars, islands, riverbends, and grade changes along the course of the river as well,” Westenskow said.

Photo by Jon Jasperson

Water Flows and Ice Accumulation Vary Year to Year

Westenskow said ice jams also occur within the City of Green River, where ice accumulates south of the FMC bridge and connects with other areas such as side channels and sand bars. When this happens, a continuous mass of ice accumulates all the way to the horse corrals.

“We often see ice through this segment of town, and some years it does a number on the boardwalk,” Westenskow said.

Photo by Jon Jasperson

Westenskow said the city has noticed that high spring runoff has caused bank erosion in town and near the Killdeer Wetlands. He said flows vary from year to year, and every high flow situation changes the river some each year.

“It is very possible that ice may form differently from year to year depending on how the spring flows modify the banks, sandbars, and islands,” Westenskow said.

Photo by Jon Jasperson

Looking into the Diversion Structure’s Role in Ice Accumulation and Next Steps

According to Westenskow, the city has received several calls regarding concerns over the ice jam, and they are currently looking into the situation. They are working in coordination with the Sweetwater County Engineer’s office for information on the river through Jamestown.

“We are looking into different aspects of the diversion structure to see if we can understand its role, if any, in how the ice accumulates and what that might mean for the future,” he said.

What would Jasperson like to see with the diversion structure?

“I’d like to see it gone, and I don’t think I’m alone in that,” Jasperson said.
Jasperson has heard that there may be a petition going around very soon the removal of the diversion structure.

In the meantime, Jamestown residents have been in contact with the Sweetwater County Emergency Management office, and first responders have been placing sandbags to protect property from being damaged, or further damaged, from the ice jams.