Add news
March 2010 April 2010 May 2010 June 2010 July 2010
August 2010
September 2010 October 2010
November 2010
December 2010
January 2011
February 2011 March 2011 April 2011 May 2011 June 2011 July 2011 August 2011 September 2011 October 2011 November 2011 December 2011 January 2012 February 2012 March 2012 April 2012 May 2012 June 2012 July 2012 August 2012 September 2012 October 2012 November 2012 December 2012 January 2013 February 2013 March 2013 April 2013 May 2013 June 2013 July 2013 August 2013 September 2013 October 2013 November 2013 December 2013 January 2014 February 2014 March 2014 April 2014 May 2014 June 2014 July 2014 August 2014 September 2014 October 2014 November 2014 December 2014 January 2015 February 2015 March 2015 April 2015 May 2015 June 2015 July 2015 August 2015 September 2015 October 2015 November 2015 December 2015 January 2016 February 2016 March 2016 April 2016 May 2016 June 2016 July 2016 August 2016 September 2016 October 2016 November 2016 December 2016 January 2017 February 2017 March 2017 April 2017 May 2017 June 2017 July 2017 August 2017 September 2017 October 2017 November 2017 December 2017 January 2018 February 2018 March 2018 April 2018 May 2018 June 2018 July 2018 August 2018 September 2018 October 2018 November 2018 December 2018 January 2019 February 2019 March 2019 April 2019 May 2019 June 2019 July 2019 August 2019 September 2019 October 2019 November 2019 December 2019 January 2020 February 2020 March 2020 April 2020 May 2020 June 2020 July 2020 August 2020 September 2020 October 2020 November 2020 December 2020 January 2021 February 2021 March 2021 April 2021 May 2021 June 2021 July 2021 August 2021 September 2021 October 2021 November 2021 December 2021 January 2022 February 2022 March 2022 April 2022 May 2022 June 2022 July 2022 August 2022 September 2022 October 2022 November 2022 December 2022 January 2023 February 2023 March 2023 April 2023 May 2023 June 2023 July 2023 August 2023 September 2023 October 2023 November 2023 December 2023 January 2024 February 2024 March 2024 April 2024 May 2024 June 2024 July 2024
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21
22
23
24
25
26
27
28
29
30
31
News Every Day |

What happened to Minnesota’s Rapidan Dam? Here’s what to know about its flooding and partial failure

What happened to Minnesota’s Rapidan Dam? Here’s what to know about its flooding and partial failure

MINNEAPOLIS (AP) — The visuals were stunning: Water from the Blue Earth River surged around a southern Minnesota dam, carrying a shipping container with it as it toppled utility poles, wrecked a substation and washed away part of a riverbank. A home on the edge of the eroded slope collapsed into the river.

Earlier this week, authorities said the Rapidan Dam near Mankato faced an “imminent threat” of collapse but later said an abutment had partially failed. The river swelled after an onslaught of rain pummeled the Midwest for days.

On Wednesday, the dam was still intact and there were no mass evacuations. Authorities said the partial failure of the abutment was caused by the recent bout of heavy rain, but a past assessment of the dam revealed it was already at risk. Here are some things to know.

What happened?

Early Monday morning, emergency management workers gave notice that water was surging over the dam. As water flows peaked, debris plugged parts of the structure and the west abutment of the dam partially failed. Conditions around the dam spun a current that was too vicious for workers to cross safely to clear the detritus.

The rush of water destroyed a power station and caused outages for about 600 households, Minnesota Gov. Tim Walz said. Water levels peaked Monday at 34,800 cubic feet per second — the normal flow is 500 cubic feet per second. Those figures make this flood the second largest in the dam’s history and the equivalent of once-a-century flooding.

The levels had begun to lower by Tuesday, county officials said.

Water continued flowing around and eroding the west side of the dam Tuesday, officials said. But as overall water levels decreased, they said the prospect of a total collapse was unlikely.

What was the condition of the dam?

Construction of the Rapidan Dam was finished in 1910 and is described by the county as a hollow concrete dam, founded on sandstone bedrock in a steep, U-shaped valley. The dam is approximately 475 feet (145 meters) long and 87 feet (27 meters) high.

It was built to generate electricity, but flooding damaged it enough in 1965 that it didn’t provide power for nearly 20 years, according to an engineering report. That report, prepared by a Minneapolis firm in 2021, said emergency repairs were required in 2002 because of “extensive undermining” of its foundation. Four more rounds of repairs followed through 2018. Flood damage in 2019 and 2020 stopped the generation of power again.

In 2019, the dam experienced what was one of its highest floods on record. Severe weather from that flood and other rainfall since have caused significant damage to the dam’s structure and usability, according to Blue Earth County, which said the dam was in a “state of disrepair.”

Further damage occurred, and an April 2023 assessment conducted by the National Inventory of Dams found Rapidan to be in poor condition.

Officials have not said whether the issues identified in past assessments led to the partial failure.

“The structural integrity of the dam has been in question for a long time,” Walz said. “The removal of the dam has been a question that’s been up there.”

What are the dangers to surrounding areas?

Areas downstream of the dam have no permanent inhabited structures, reducing the risk of fatalities and property damage, county officials said. But officials closed a park downstream that attracts hikers and fishermen.

The reservoir upstream of the dam provides power generation storage and recreation. But it is full of sediment, making boat access difficult, the county said. Because the reservoir is full, sediment is now pushed downstream of the dam.

Blue Earth County Public Works Director Ryan Thilges said there is more than a century’s worth of sediment upstream of the dam. Severe environmental damage could occur if that sediment were to break loose and seep into the river, he said.

What would it cost to repair the dam?

The 2021 engineering report put the cost of repairing the dam at $15.2 million — in addition to more than $6 million that the county had spent since 2002.

But a county report the following year raised questions about the idea. It said that even if the dam’s ability to generate electricity were restored, the county still would likely lose money — an average of almost $107,000 annually for each of the following 40 years.

And the 2021 engineering report said that after 40 years, the county still would face the same issue — whether to remove the dam. It said repairs would require three years of planning and a year of construction.

Could the county remove the dam?

A separate 2021 study by the same engineering firm suggested that removing the dam would have benefits. It called the potential move “an outstanding opportunity to re-establish a free-flowing river” while turning the former lake into 360 acres of parkland.

The actual removal of the dam would cost $10 million, but the project would come with a lot of other costs, such as stabilizing riverbanks, preventing erosion and replacing a county road bridge over the dam — increasing the potential costs to $82 million.

What’s more, the report said, it could require five years of planning and another five years of work afterward. The report said the Minnesota Legislature might be required to authorize bonds to pay for it.

The work would require the county to install a temporary dam upstream and divert the river around the Rapidan Dam so crews could work on dry ground and bring in equipment.

“Sometimes it’s explosives. Sometimes it’s less dramatic — it’s a backhoe coming and hacking away at it,” said Amy Souers Kober, spokesperson and a vice president for the conservation group American Rivers, which monitors dam safety issues.

___

Hanna reported from Topeka, Kansas.

Source

Москва

Врач Тяжельников рассказал о серьезных рисках при отдыхе на пляже

Bears Reportedly Played A Big Part In Giants Losing Saquon Barkley

Biden's anger bleeds through as party weighs his future

Faculty of International Journalism and Mass Communications Eurasian International University is conducting an additional intake of applicants!

Surya set to pip Hardik , emerges as dark horse for India's T20I captaincy

Ria.city






Read also

British tourist, 66, dies after being pulled unconscious from water at Greek island

Nayar, ten Doeschate set to join Team India as assistant coaches: Report

North China bridge collapse kills 11, leaves over 30 missing

News, articles, comments, with a minute-by-minute update, now on Today24.pro

News Every Day

Biden's anger bleeds through as party weighs his future

Today24.pro — latest news 24/7. You can add your news instantly now — here


News Every Day

Bears Reportedly Played A Big Part In Giants Losing Saquon Barkley



Sports today


Новости тенниса
Ролан Гаррос

Уроженка Самарской области выступит на Олимпиаде в Париже



Спорт в России и мире
Москва

Скиппинг и танцы: как тренировки со скакалкой влияют на физическое здоровье



All sports news today





Sports in Russia today

Москва

Ротенберг о матче звезд КХЛ и НХЛ: «Не терпится увидеть коллег-тренеров, ребят, с которыми прошли огонь и воду, играли на ЧМ, побеждали на Олимпийских играх»


Новости России

Game News

I didn't expect my favorite cozy MMO to do a crossover with a Finnish children's series


Russian.city


Мир

Подсчитано, насколько подорожали авиабилеты на российские курорты: если вы ещё не купили билет, то вы опоздали


Губернаторы России
Общество

Общество: Скоростное движение в обход Твери и Тольятти укрепит экономику и логистику России


Власти Санкт-Петербурга подтвердили осквернение памятника Евгению Пригожину

Ефимов: бизнес выкупил у Москвы 240 арендованных помещений с начала года

Певец Дмитрий Камский готовит к релизу новый сингл "Песня Земли"

Экс-замминистра обороны Иванов просит выпустить его из СИЗО


Концерт «Бах vs Бетховен» от Amadeus Concerts

Столичные музыканты стали лауреатами конкурса композиторов в рамках «Академии джаза Игоря Бутмана»

Народный артист России Игорь Бутман: «В джазе не надо ничего понимать»

Книжный обзор: простуженный Фрэнк Синатра, кофейня в Киото и сибирские шаманы


Красноярскую теннисистку Мирру Андрееву допустили на Олимпиаду в Париже

Медведев в матче против Синнера на Уимблдоне проявил характер, заявил Ольховский

Принцесса Кейт Миддлтон надела на Уимблдон платье в цветах теннисного клуба

«Такими вы их никогда не видели». ATP опубликовала видео с Медведевым и Рублёвым



Shaman объяснил, почему выступил у посольства США в Москве

Москва слезам не верит: в ТПП РФ подержали инициативу по защите прав предпринимателей

Shaman назвал выступление у посольства США ответом РФ на блокировку на YouTube

Скиппинг и танцы: как тренировки со скакалкой влияют на физическое здоровье


Дональд Трамп изменил обращение к съезду республиканцев после покушения

Сергей Собянин. Главное за день

Один из лучших джазовых вечеров в Петербурге и Москве - «Jazz под Небом»

Заводы АО "Желдорреммаш" выбирают лучших в своей профессии


В Коми выросла неформальная занятость

«Надо подавать в суд»: Мария Аронова опровергла сообщения о своей госпитализации

Из Владимира в Москву и обратно теперь можно доехать быстрее по М-12

Игорь Руденя поздравил жителей Кесовогорского округа с Днём муниципального образования



Путин в России и мире






Персональные новости Russian.city
Алла Пугачёва

Бомжи поселились в эксклюзивном лимузине Пугачевой



News Every Day

Surya set to pip Hardik , emerges as dark horse for India's T20I captaincy




Friends of Today24

Музыкальные новости

Персональные новости