MANKATO — State lawmakers, visiting Mankato last month to view a $2.3 million funding request from the city, were repeatedly told that the rapid erosion of a Minnesota River bank was an immediate threat to a major Mankato well.

On Tuesday, the City Council is expected to reinforce the emergency-nature of the problem by approving nearly $900,000 for riverbank repairs this winter, hoping the Legislature will approve funding assistance in about six months.

“We need to be in the best position to start the work right away,” City Manager Pat Hentges said.

Hentges is optimistic about later help from the state based on the response of members of House and Senate bonding committees who visited the site of Well No. 15 in Land of Memories Park.

“They understand the problems,” he said.

Those problems include the loss of 58 feet of land between the Minnesota River and the well in the past decade, leaving only about 15 feet of leeway between the river and a water source that provides more than a third of Mankato’s water-supply capacity. The Legislature won’t convene until February, and a statewide bonding bill — financing $1 billion or more in construction projects across Minnesota — is typically not approved until shortly before lawmakers adjourn in May.

Protecting the well will involve placing thousands of tons of riprap along two sections of the river’s east bank on Land of Memories’ west side. It’s work best done in winter when river levels are low and the ground is firm.

“We’re in the process of final designs and seeking permits,” Hentges said.

But quartzite — the extra-hard rock that works best for riprap — is available from a limited number of quarries, and a major snowfall could shut those quarries down. So the city is hoping to put out a call for bids, select a supplier, and have 8,546 cubic yards of quartzite chunks delivered and in place so the stabilization project can begin by mid-February.

A similar amount of gravel, topsoil and other material will also be needed as the eroded riverbank is reshaped and armored against future erosion from a river that’s been flowing at uncommonly high levels in recent years.

Although properly placed riprap is effective in stabilizing riverbanks, Hentges said the project will change the look of that edge of Land of Memories.

“You’re going to see a disruption for the fields closest to the river,” he said. “We’ve already stopped maintaining that, and a lot of that slope will be affected.”

As part of its consent agenda, the council is expected to approve without discussion the $900,000 expenditure to get the quartzite in place.

The city will be asking lawmakers to cover 80% of the total project cost, which could approach $2.3 million, and Hentges is confident about the odds of success — eventually.

“We’ve got a good story to tell,” he said.