HC Roads Department drilling into ‘frost boils’ to help drainage on gravel roads

The Henry County Roads Department drilling into frost boils on gravel roads in an attempt to help moisture escape and improve roads in coming years.

Frost boils are created when frost in the gravel roads melts but can't drain away because of compacted ground underneath the road. Jake Hotchkiss, Henry County Engineer, said they call where the water won't drain a 'hard pack.”

'We locate the worst ones, drill into the ground and put clean rock in to help get that moisture out,” Hotchkiss said. 'The hard pack is the layer that stops moisture.”

Hotchkiss said the department drilled into frost boils about five years ago, and the ones they fixed have not come back.

'Normally, you'll get them back. You can't just throw rock on frost boils,” Hotchkiss said.

Hotchkiss said holes are being drilled 4 to 5 feet deep in these problems spots to allow water to drain somewhere else. While this may not have an immediate effect, Hotchkiss said it will improve gravel roads in the future.

Overall, Hotchkiss said Henry County's gravel roads are in 'pretty good shape” compared to the rest of Iowa.

'We're really fortunate where we're at right now from what I'm hearing from other county (engineers),” Hotchkiss said. 'So far, the public has been patient and understanding.”

Last week, the Roads Department spent most days hauling spot rock. They worked on signs, worked on a ditching project on Quarry Road, worked on drainage issues on Iowa Avenue, and worked on a small ditching project on Lexington Avenue.

They also received a truck load of mulch to begin seeding operations.