What is the history of the Rapidan Dam in southern Minnesota?

RAPIDAN TOWNSHIP, Minn. — On Monday, officers in southern Minnesota introduced the Rapidan Dam had been breached and is in “imminent failure situation.”

Residents in low-lying areas of the Minnesota River Valley are suggested to carefully monitor the scenario and put together for the potential of evacuation.

The Nationwide Climate Service says the failure is anticipated to trigger the Minnesota River at Mankato to crest just under main flood state on Tuesday morning.

What’s the historical past of the Rapidan Dam?

The Rapidan Dam is positioned on the Blue Earth River in Rapidan Township — about 14 miles south of Mankato. 

When it opened in 1910, the dam doubled the ability capability of Mankato’s electrical system, in keeping with the Blue Earth County Historic Society.

The dam was constructed utilizing hole strengthened concrete.

The dam was owned and operated by Northern States Energy Firm till 1970 when it provided the dam and surrounding 750 acres to Blue Earth County “as an environmental hall of wildlife habitats, recreation areas and nature trails,” says the county’s historic society.

Nevertheless, in 1972, the historic society says the county board dominated the dam ought to both be rebuilt or torn down for the reason that dam would trigger “appreciable harm” to the encompassing areas ought to it collapse.

To handle security issues, engineers added extra concrete reinforcement to the Rapidan Dam within the Nineteen Eighties. The Nationwide Society of Skilled Engineers referred to as the renovations “one of many prime engineering feats of 1986.”

In 2002, emergency repairs have been made after discovering intensive undermining of the dam’s basis.

Blue Earth County says that over time, Rapidan Dam has skilled common flooding, with the second-highest flood on document occurring 5 years in the past, in 2019. That flooding prompted “important harm to the dam’s construction and value,” and it has not been in a position to produce vitality since then, in keeping with the county’s web site.

A research from 2021 recognized two possible options for the dam: restore it or take away it.

From 1999 via 2022, a report discovered that the dam really misplaced Blue Earth County over half one million {dollars}.

Officers for Blue Earth County shaped the Way forward for Rapidan Dam to “establish the neighborhood’s wants and issues and use their enter” to make one of the best choice concerning what to do with the dam.

A dam restore feasibility report commissioned by the county in 2021 estimated it will value not less than $15.1 million to restore the dam. Nevertheless, the county stories it will possible lose over $4 million on the dam over 40 years. Eradicating the dam was estimated to value at a minimal of $65.2 million.

In August 2022, Blue Earth County introduced the ultimate engagement abstract, which discovered nearly all of folks surveyed supported the dam being repaired.

In the end, since each choices had important prices, neither have been carried out.

In March 2023, Blue Earth County started the Federal Vitality Regulation Fee licensure exemption give up course of for the Rapidan Dam for the reason that dam is now not producing hydroelectricity.