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Project to reinforce structures damaged by historic floods

The remnants of damage from flooding in the spring 2019 can still be seen in eastern Nebraska.

From flooded farm fields to damaged homes and washed out bridges and roads, the state is still recovering from the historic event.

OPPD is also making changes due to the flooding. The utility is reinforcing three structures on two transmission lines that cross the Platte River. Because of the flooding, the Platte River widened and changed course.

New locations

As floodwaters moved swiftly, they scoured away river banks. Structures that were once a considerable distance from the bank are now located in the river channel.

“These structures were not designed to be in the middle of the river,” said Shane Hanson, lead engineer in Transmission Engineering at OPPD. “We must now go in and restore the foundations so they are back to their original state.”

The Platte River, for example, migrated 900 feet to the west of its previous channel. The difference can be seen in the photo below. The circles on the photo indicate OPPD transmission structures.

Reinforcement

The project will reinforce and rebuild the base of the transmission structures so they can withstand the moving water that now surrounds them.

The new structure is similar to a typical bridge crossing on a river, Hanson said. The foundations are protected like it is on the bridge. To reach the structures, a contractor will need to build temporary roads and bridges out into the water to deliver materials.

Construction is scheduled to start in October. February 2020 is the targeted completion date. OPPD is currently reviewing contractor bids and awaiting the finalization of Army Corps of Engineer permits so they can build within the river.

“The goal is to be complete prior to the start of the next flooding season,” said Dannie Buelt, interim director of Engineering at OPPD. “With a structure in the river, it’s more susceptible to damage from ice in the river.”

The project has an overall budget between $3 and $4 million. The other option was to rebuild the transmission line, which would have had a considerably higher cost, and taken multiple years.

By considering a rebuild of the bases, it has less impact on OPPD’s system and less cost. However, OPPD is tracking everything related to the project and will submit it to FEMA for reimbursement in relationship to federal flooding relief.