Kathy Klehr calls it “surreal,” the sign you pass on the flood plain near downtown Shakopee.

It shows just how high the water reached in the most destructive flood ever to hit the piece of land you’re passing through, on Hwy. 101, as well as much of southern Minnesota.

“That sign is an icon,” said Klehr, head of the Scott County Historical Society. “When you’re talking weather history in Minnesota, the Blizzard of ’40 and the Floods of ’65 are the ones that really stick out. Every spring you think of it: Will you be hit like that again?”

An open house in Shakopee Thursday marks a big step in the long struggle to finally lift Hwy. 101 above all but the most catastrophic floods.

It’s being called the Southwest Reconnection Project, a two-stage effort that is to launch in 2014 and 2015. It comes after the area has been jolted more and more often by longer and longer closures.

The 1965 flood was devastating, leaving several thousand people homeless for a time and closing Hwy. 169 all the way from Le Sueur to Mankato. It followed a winter so snowy in southwest Minnesota that drifts reached the rooftops of homes.

The paradox is that while the sign shows a higher waterline in 1965 than in any other year, transportation disruption in certain spots was much milder back then than it is today.

A 2011 study found that Hwy. 101 was closed for 15 days in 1965 but for 27 days in 1993 and 2010, and for 43 days in 2011 — an ominous trend that raises the cost of the disruption and the payoff from fixing it. Shorter closures — though way more frequent than in the past — have been sprinkled in between.

Deb McMillan, president of the SouthWest Metro Chamber of Commerce, estimates that businesses relying on drive-by traffic lose as much as 70 percent of their trade when traffic shifts to other river crossings.

Thursday’s open house will cover two projects that are linked together, one of which isn’t to happen until 2015.

– introducing it and asking for feedback.”

One element that could draw comment is a planned roundabout instead of the T-type intersection that now connects the two roads.