The Free Press, Mankato, MN

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March 22, 2011

Rain adds to flooding predictions

NEW ULM — As city workers busily prepared a berm this week to keep Minnesota River floodwaters from damaging homes, it was water from the Minnesota sky that proved to be a bigger problem.

Rain canceled all work being done in New Ulm Tuesday to construct a berm that will, city officials hope, protect a string of homes on a pair of streets that run along the river.

New Ulm City Manager Brian Gramentz said the rain, between a half inch to an inch across the region, made the ground beneath too soft to work on.

“Anytime you put 40,000 pounds on nice wet grass, it’s gonna sink,” Gramentz said.

They considered hauling in rocks to pave the heaviest traffic areas but decided that waiting a day would make more sense.

Gramentz said they’ll still most likely finish by Thursday, which will be before the river is expected to crest in New Ulm.

“The floods aren’t necessarily pressing at this point in New Ulm,” Gramentz said. “The projected high level for this week is, like 803 feet, or almost 804. The current berm being constructed is at 814. At least through this week, we won’t be inundated.”

The rain forced the National Weather Service to quickly reconfigure its river-level estimates for cities all along the Minnesota River. They spent much of the day checking water gauges and plugging the levels into computer models. The new levels, should they turn out to be accurate, would make this year’s flood the third worst on record, trailing floods from last fall and 1993.

River level predictions rose about a foot after Tuesday’s rain. (The new predictions take into account precipitation in the forecast through this afternoon.)

Because of the weather conditions, the National Weather Service was unable to use radar to determine accurate waterfall totals around the region.

“We had to really rely on our rain gauges,” said Diane Cooper of the NWS.

Readings are up all over, Cooper says. She suggests cities take a good look at the new warnings and compare them to their plans to make sure they’ve done everything they need to do to keep their cities dry.

In New Ulm, for instance, the river at about noon was at about 798 feet. The NWS predicts the river will crest sometime next week at about 804 feet, well below its berm.

In Mankato, the river was measured at 11 a.m. Tuesday to be at 22 feet, and is expected now to rise to about 28 feet as early as Friday.

Down river from Mankato, Henderson also will see higher amounts than were predicted prior to the rains.

Highways 93 and 19 from the east that run through Henderson are closed and the flood gates on the levee have been installed. The city is reachable from the west on Highway 19. The river level in Henderson as of Tuesday afternoon was 734 feet. It is expected to crest at about 739 feet Saturday evening.

Highway 93 from Highway 169 into Le Sueur was closed at about  6 p.m. Tuesday.

The Minnesota River isn’t the only one swelling.

River waters in Garden City and Rapidan also continue to rise but have not yet reached levels recorded during 2010’s autumn flood.

In Rapidan, the Blue Earth River reached a depth of 12.5 feet Tuesday. Fields and yards, especially on the outskirts of town, were pocked with large pools of standing water.

Last fall, the river reached a maximum depth of 16 feet and the all-time peak is more than 21 feet, recorded in 1965.

In Garden City, the Watonwan River reached 12.4 feet — which is also below last fall’s 18 feet and the highest recorded level of 20 feet in 1969. Although, at the public water access under the County Road 13 bridge, the river has widened past the bridge supports and nearly to the parking area.

Back in New Ulm, Gramentz chuckles a little when pondering their flood battle this year.

The city spent $300,000 to install the berm and had figured it better prepare for a worst-ever flood.

It looks like some of that berm might not have been necessary, but Gramentz is confident the city made the best decision given the information it had at the time. Plus, everything could change with another big rain. They might need that extra few feet after all.

“The governor said a week a go, ‘Plan for the worst, hope for the best,’” Gramentz said. “Right now we’ve got a really big berm for a relatively small flood event.”

The city will likely build a permanent levee soon at a cost of about $2 million.

— Free Press Staff Writer Tanner Kent contributed to this report.

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