Dam Failures and Infrastructure Damage in a Changing Environment

[Astronuc]

Climate change is increasing stress on thousands of aging dams across the US
Published: July 13, 2023 8:37am EDT Updated: June 24, 2024 7:27pm EDT
https://theconversation.com/climate...-thousands-of-aging-dams-across-the-us-209568

Heavy rainfall generated widespread flooding. in the Upper Midwest in late June 2024, putting at least one aging dam at risk. In southern Minnesota, the Blue Earth River cut a path around the Rapidan Dam in Rapidan Township, about 15 miles south of Mankato, on June 24, putting the structure at imminent risk of failing. Officials warned local residents that if the dam burst, the river could rise by 2 feet, but said that evacuations were not needed.

This event comes a year after flooding in Vermont collapsed at least one dam and threatened others. Hiba Baroud, associate professor and associate chair in the department of civil and environmental engineering at Vanderbilt University, explains how flooding stresses dams in a changing climate.

How old are most US dams?

There are more than 91,000 dams across the U.S., in all 50 states, with diverse designs and purposes. The average dam age is 57 years, and more than 8,000 dams are over 90 years old.

Every four years, the American Society of Civil Engineers produces a report card for the nation’s infrastructure that assigns grades based on the condition of structures like roads, bridges and dams, and the investments that they need. The most recent report card estimates that 70% of U.S. dams will be more than 50 years old by 2030.
Overall, the report gave U.S. dams a “D” grade and estimated that more than 2,300 high hazard potential dams – those that could cause loss of life or serious property damage if they fail, based on the level of development around them – lacked emergency action plans.

Certainly there needs to be some consideration with respect to the changing environment and impact on older dams not designed for extreme weather.

Are there ways to strengthen older dams against flooding without completely replacing them?

Decommissioning or replacing dams can be complicated and cost-prohibitive. It also can have cascading effects on the surrounding community, and possibly on other infrastructure. Regularly maintaining and upgrading older dams can be a cost-effective way to strengthen them and make them resilient to natural hazards.

When dams no longer serve the purposes for which they were built, they may be partially breached or entirely removed to restore the river’s natural flow.

The Association of State Dam Safety Officials estimates that it would cost US$157.7 billion to rehabilitate all nonfederal dams in the U.S. Of this amount, about one-fifth ($34.1 billion) is for rehabilitating high-hazard potential dams. The 2021 Infrastructure Investment and Jobs Act includes approximately $3 billion for dam safety projects, focusing on rehabilitation, retrofitting and removal.

Extreme weather events associated with a changing climate are producing more frequent flooding events in various parts of the US and world in general.

Infrastructure designed for a cooler environment are now at risk.

More generally, cases studies of dam incidents and failures
https://damfailures.org/case-study/


For example - flooding of the Red River, border between North Dakota and Minnesota, the 2019 flooding of the Niobrara River in northern Nebraska, and the current flooding (June 2024) of the Big Sioux and Blue Earth Rivers affecting South Dakota, SW Minnesota and NW Iowa.

Red River and Valley - Prone to flooding
https://en.wikipedia.org/wiki/Red_River_Valley#Prone_to_flooding
https://en.wikipedia.org/wiki/Red_River_of_the_North#Floods
Major floods in historic times include those of 1826, 1897, 1950, 1997, 2009, 2011, and there has been significant flooding many years in between.


Nebraska Flooding on the Niobrara River: March 2019
https://storymaps.arcgis.com/stories/9ce70c78f5a44813a326d20035cab95a

Loss of the Spencer Dam (on Niobrara River)
https://damfailures.org/case-study/spencer-dam-nebraska-2019/

https://www.weather.gov/gid/march2019flood

During a multiple-day stretch centered from March 13-23, 2019 (but peaking in severity March 13th-17th), several Nebraska counties mainly along/north of Interstate 80 within the NWS Hastings coverage area endured widespread flooding, ranging in scope from minor/moderate to historical/catastrophic (the likes of which had not been observed in several decades). By far the worst flooding occurred along several primary rivers, including the Loup River system (including North and South branches), Cedar River and Wood River (among others, see record crest information below). Not only was this flooding characterized by high water levels (as is the case with all floods), but in many areas damage was also augmented by an unusually-severe break-up of thick river ice. Taking a back seat to the widespread flooding in terms of impacts/severity, much of the local area also endured a winter storm with high winds and blizzard conditions on the night of the 13th into the morning of the 14th.

Nebraska’s Spencer Dam will not be rebuilt in wake of historic 2019 flood
https://www.wowt.com/2021/05/05/neb...ot-be-rebuilt-in-wake-of-2019-historic-flood/


Rapidan Dam in southern Minnesota experiences partial failure; no plans for mass evacuation
https://www.cbsnews.com/minnesota/news/rapidan-dam-fails-evacuation-blue-earth-county/

https://www.cnn.com/2024/06/26/us/minnesota-house-river-rapidan-dam/index.html
The Dam Store, known for its homemade pies, has been in business since 1910 and owned by Barnes’ family since 1972.

Chart Shows Big Sioux River's Record-Breaking Flooding Spike
https://www.newsweek.com/big-sioux-river-flood-chart-iowa-storms-1916744
https://www.kwit.org/podcast/spm-ne...nor-reynolds-tours-many-nw-iowa-flooded-areas
https://listen.sdpb.org/environment...rd-level-as-flooding-persists-in-southeast-sd


https://en.wikipedia.org/wiki/Big_Sioux_River#Flooding
The Big Sioux River experienced record-breaking flooding during the 2019 Midwestern U.S. floods.

And now, the Big Sioux River is having record flooding in 2024.

https://southdakotasearchlight.com/...oads-in-mccook-lake-area-ravaged-by-flooding/
https://southdakotasearchlight.com/...re-sacrificed-and-they-want-a-new-flood-plan/

https://www.dakotanewsnow.com/2024/06/24/north-sioux-city-railroad-bridge-collapses/

BNSF Railroad bridge collapses into Big Sioux River


https://www.trains.com/trn/news-rev...ge-on-south-dakota-iowa-state-line-collapses/
KTIV-TV reports that the level of the Big Sioux River was at 44.25 feet as of 7:30 p.m. Sunday, surpassing its record of 37.7, but is believed to have crested.

The bridge, on a former Milwaukee Road line that is part of BNSF’s Aberdeen Subdivision, is also used by the D&I Railroad through trackage rights on BNSF between Elk Point, S.D., and Sioux City.

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The North Sioux City railroad bridge has an interesting and long history. Originally, the trusses were built for the Cedar River Bridge: Cedar Rapids, Iowa. The trusses were moved and installed at the North Sioux City location in 1905 by the Chicago, Milwaukee St. Paul & Pacific Railway (aka The Milwaukee Road). So the bridge has been standing there for 119 years. The truss works were fabricated by Lassig Bridge & Iron Works of Chicago.
http://johnmarvigbridges.org/North Sioux City Rail Bridge.html

Upstream of the North Sious City bridge is the Elk Point Rail Bridge between Westlfied, Iowa and Elk Point, South Dakota
http://johnmarvigbridges.org/Elk Point Rail Bridge.html


The D&I Railroad (reporting marks DAIR) is a Class III shortline and wholly-owned subsidiary of L. G. Everist, Inc., owners of one of the largest privately-owned fleets of railroad equipment of any aggregate producer in North America.
https://www.lgeverist.com/dirailroad/
https://iowadot.gov/iowarail/pdfs/diar.pdf (the filename is mis-spelled; it should be dair.pdf)

 

[Baluncore]

I believe the take-away message is that dam design emphasises holding back water, but when that water flow exceeds the design capacity, it is the spillway that must protect the structure.

Spillways are designed to withstand a maximum flow. When that maximum is exceeded, all that extra energy must go somewhere, so it goes into eroding the foot of the spillway structure, which often cuts back upstream, undermining the dam wall.

 

[Vanadium 50]

I think bringing "climate change" into it is a mistake, as it a) instantly politicizes things in an unhelpful manner, and b) is IMHO unnecessary and irrelevant. To my mind, the problem is 57 years. If they are designed to withstand a once in a century event, you have a problem.

Saying the same thing more numerically, 91000 dams x 57 years = 5 million dam-years. That's the MTBF we need if we don't want to see one go. That's tough. It's tougher still with old dams instead of new dams.