Releases may hit 2,400 cfsDiking will be needed in some parts of Jamestown to handle the largest releases from the Jamestown and Pipestem dams since 2009, officials said at a meeting Wednesday night.
By: Ben Rodgers, The Jamestown Sun
Diking will be needed in some parts of Jamestown to handle the largest releases from the Jamestown and Pipestem dams since 2009, officials said at a meeting Wednesday night.
Heavy rains over the course of this spring and summer have forced the U.S. Army Corps of Engineers to develop the plan for increased releases.
Combined releases from the Jamestown and Pipestem reservoirs are projected to get as high as 2,220 cubic feet per second and could get up to 2,400 cfs if there is another major rain event.
City Engineer Reed Schwartzkopf said he anticipates 2,700 feet of dikes to go up by the end of next week. Of that 2,700 feet, he said, he expects 1,000 feet to be what he considered major diking.
“We don’t really have materials completely chosen yet, the emphasis is to do primarily sandbags, maybe some Hescos,” Schwartzkopf said. He said one area by Business Loop East will see a clay dike.
Some areas of Jamestown that will require minor diking will be south of the confluence of the James and Pipestem rivers, north of the confluence by the Anne Carlsen Center and in the area of Business Loop East, he said.
He said the city will use city crews, local contracting crews, available contracting crews and the North Dakota National Guard, if necessary.
In total, he said, there are seven areas of concern and three or four are by Business Loop East. Diking in those seven areas would have a minimal impact on the city, Schwartzkopf said.
He stressed that communication efforts have been improved this year. He said during last Friday’s rain event that there were nine gate changes in less than eight hours to adjust water inflows within Jamestown.
The reason the corps recently adjusted its plan for outflows is because of that rain event, which dumped anywhere from 2 to 4 inches of water throughout the James River Basin.
“You can see it’s absolutely dwarfing the previous level of runoff into the projects and through Jamestown,” Tim Temeyer, corps hydrologist out of Omaha, Neb., said of this year’s precipitation combined with last year’s snow pack.
Elevation at the Jamestown Reservoir as of last night was 1,449.9 feet, or 72 percent full, and rising.
Elevation at the Pipestem Reservoir is at 1,488.2 feet, or 74 percent full, and also rising.
Combined releases have been at 1,800 cfs since late April. Temeyer said anything more than 2,100 cfs would require some minor diking.
The maximum anticipated elevation for the Jamestown Reservoir is 1,451 feet, which is expected to be reached sometime in the next week.
Pipestem is expected to top off at 1,491 feet sometime between Aug. 19 to Aug. 25.
The maximum amount of releases is unknown because of what the weather could do.
“I wish I could tell you today exactly what we’re going to go to but I just don’t know that,” Temeyer said in front of a projected graph of releases. “Yes, I have a feeling we are going to go this high, right around the 2,200 range.”
The current 14-day forecast doesn’t call for any major rain events, Temeyer said. But it could still be until mid-to-late November before both reservoirs are at the flood control level.
Temeyer said the corps will take all precautions to avoid winter releases.
One concern that came up was wave action for cabins on the Jamestown Reservoir.
Stutsman County Sheriff Chad Kaiser urged boaters to not cause wakes by the cabin area because the waves can damage properties with such high water levels.
Until then the corps looks to increase releases at 50 cfs per day for the next few days. Temeyer said advance notice will be given so property owners that might be affected have time to take the necessary measures.
“We’re going to have to bite the bullet on a city level to let them (the corps) get control of it and get it done,” Schwartzkopf said.
Sun reporter Ben Rodgers can be reached at 701-952-8455 or by e-mail at firstname.lastname@example.org