Tim Krohn: Ask Us: Reader wonders about new pole and platform in park

Jun. 4—Q: There is a pole with a platform placed in North Mankato's Spring Lake Park. Is it for birds to nest? Also there used to be recycling bins in the park and they aren't there anymore. And do they enforce the leash law in the park? There used to be signs posted, but they aren't there anymore.

A: Stand In Ask Us Guy learned from the city that the platform is indeed for the birds. Now they just need would-be nest builders to find it.

"Hopefully it will draw an osprey," said Duane Rader, the city's parks and water superintendent.

The pole and platform were erected in February on the south end of the park, near the playground and a ball field. There are ospreys that frequent the area, circling until they lock onto a fish and then doing a dramatic dive into the water and more often than not emerging with lunch in their claws.

The group Osprey Watch says on its website that osprey platforms should have multiple drain holes to prevent flooding during heavy rain, be designed to discourage ground predators from getting to the eggs and should be at least 3 feet by 3 feet and able to support 300 pounds of weight.

As for the recycling bins, Rader said too much non-recyclable garbage was thrown into them, so they were removed.

Rader said a variety of signage is being replaced in the park and there have just been some push-in signs installed reminding people of the city's leash ordinance and asking them to pick up after their pets.

Q: The new Blue Earth County Road 1 is a beautiful road with some high retainer walls up against the bluffs. On the top of the walls is what looks like railings. What are they there for?

A: Blue Earth County Public Works Director Ryan Thilges said the construction of the retaining walls was an interesting and often complex project.

The walls are topped by a metal railing and above some of the walls is black fencing that runs along private property lines near the top of the bluff. The railings are a safety measure because of the steep bluff, aimed at keeping wildlife back or protecting people in the unlikely case of someone climbing around the bluff.

Once known as state Highway 66, the 12-mile stretch of what is now County 1, was transformed in the nearly $37 million reconstruction project that stretches from the Mankato city limits to Good Thunder.

"Because of the topography along that segment from County Road 9 to County Road 90, it's very steep ravine slopes and bluffs, so to be able to build the road through there the width we needed and for drainage, we need the walls."

The project used two types of walls, one a more traditional approach using large blocks to build the walls in two spots along the road.

The other technique is called a soil nail retaining wall that is built from the top down, Thilges said.

Holes were drilled at an angle into the steep bluffs and 30- to 40-foot-long steel bars (nails) were inserted and grouted into place. Reinforced steel was built down the slope, anchored to the nails.

"Then they put the aesthetic face wall over it." The wall facade used sprayed-on concrete (shotcrete) that is formed to mimic natural stone.

Thilges said specialized contractors were used for the wall project.

"The reason we used the soil nail walls is we looked into typical retaining walls, but that takes a lot of excavation and you'd be deforesting the hillside. We wanted to maintain the natural beauty of that corridor and the trees," he said.

"We're really happy with the road and safety it represents."

Tim Krohn is Stand In Ask Us Guy. If you have a question for the regular Ask Us Guy contact Ask Us at The Free Press, 418 S. Second St., Mankato, MN 56001. Call Mark Fischenich at 344-6321 or email your question to mfischenich@mankatofreepress.com; put Ask Us in the subject line.