Op een koude ochtend afgelopen maart, Kenny Angel werd verwoed op zijn deur geklopt. Twee arbeiders van een nutsbedrijf in het noorden van Nebraska waren gekomen met een scherpe waarschuwing:ga je huis uit.

Iets meer dan een kwart mijl stroomopwaarts, de 92-jarige Spencer Dam deed zijn best om de gezwollen, met ijs bedekte Niobrara-rivier na een ongewoon intense sneeuw- en regenbui. De arbeiders hadden geprobeerd, maar slaagden er niet in om de bevroren houten overlaatpoorten van de dam te openen. Dus, het ergste vrezen, ze vluchtten in hun vrachtwagen, stoppen om Angel te waarschuwen voordat hij wegrijdt zonder hem.

Minuten later, de dam stortte in, het ontketenen van een golf van water met ijsbrokken zo groot als auto's. Angel's huis werd weggevaagd; zijn lichaam werd nooit gevonden.

"Hij had een opzegtermijn van ongeveer 5 minuten, zonder voorafgaande waarschuwing de dag ervoor, "Scott engel, een van Kenny's broers, zei.

Staatsinspecteurs hadden de dam minder dan een jaar eerder een "redelijk" cijfer gegeven. Tot het mislukte, het zag er weinig anders uit dan duizenden anderen in de VS - en dat zou een probleem kunnen zijn.

Een meer dan twee jaar durend onderzoek door The Associated Press heeft gevonden dat tientallen dammen in het hele land in nog slechtere staat verkeren, en op even gevaarlijke locaties. Ze steken boven huizen uit, ondernemingen, snelwegen of hele gemeenschappen die te maken kunnen krijgen met levensbedreigende overstromingen als de dammen het niet houden.

Een overzicht van federale gegevens en rapporten verkregen onder staatswetten voor open registers identificeerde 1, 688 dammen met een hoog risico beoordeeld in slechte of onbevredigende staat als vorig jaar in 44 staten en Puerto Rico. Het werkelijke aantal is vrijwel zeker hoger:sommige staten weigerden conditiebeoordelingen te geven voor hun dammen, het claimen van vrijstellingen voor verzoeken om openbare registers. Anderen hebben eenvoudigweg niet al hun moederdieren beoordeeld vanwege gebrek aan financiering, personeel of bevoegdheid om dit te doen.

Het aantal sterfgevallen als gevolg van het falen van dammen is afgenomen sinds een reeks catastrofale instortingen in de jaren zeventig de federale en deelstaatregeringen ertoe aanzette hun veiligheidsinspanningen op te voeren. Toch ongeveer 1, 000 dammen zijn de afgelopen vier decennia gefaald, 34 mensen vermoorden, volgens het National Performance of Dams-programma van Stanford University.

Gebouwd voor overstromingsbeheer, irrigatie, water voorraad, waterkracht, recreatie of opslag van industrieel afval, de dammen van het land zijn gemiddeld meer dan een halve eeuw oud. Sommige zijn niet langer geschikt om de hevige regenval en overstromingen van een veranderend klimaat aan te kunnen. Toch wordt er op ze vertrouwd om steeds meer mensen te beschermen naarmate woningbouwprojecten in de buurt opduiken.

"Er zijn duizenden mensen in dit land die stroomafwaarts van dammen leven die gezien de huidige veiligheidsnormen als gebrekkig worden beschouwd. " zei Mark Ogden, een voormalige veiligheidsfunctionaris voor dammen in Ohio, die nu technisch specialist is bij de Association of State Dam Safety Officials.

De vereniging schat dat het meer dan $ 70 miljard zou kosten om de meer dan 90, 000 dammen. Maar in tegenstelling tot veel andere infrastructuur, de meeste Amerikaanse dammen zijn in particulier bezit. Dat maakt het voor regelgevers moeilijk om verbeteringen te eisen van operators die de hoge kosten niet kunnen of willen betalen.

"De meeste mensen hebben geen idee van de kwetsbaarheden wanneer ze stroomafwaarts van deze particuliere dammen leven, " zei Craig Fugate, een voormalig beheerder bij de Federal Emergency Management Agency. "Als ze falen, ze falen niet met een waarschuwing. Ze falen gewoon, en plotseling kun je jezelf in een situatie bevinden waarin je met heel weinig tijd een muur van water en puin naar je huis hebt rennen, indien van toepassing, om eruit te komen."

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Het is onduidelijk of Angel, een 71-jarige veteraan uit de Vietnamoorlog, weigerde te vluchten of had simpelweg geen tijd meer nadat arbeiders van het Nebraska Public Power District hem hadden gewaarschuwd dat het water de dam bij Spencer overstroomde, een stad met minder dan 500 inwoners.

Een advocaat voor Angels vrouw, die niet thuis was toen de dam brak, heeft een rechtszaak van $ 5 miljoen aangespannen wegens nalatigheid. Het beweert dat het elektriciteitsbedrijf de dam niet goed heeft onderhouden, haar medewerkers opleiden of de Angels op de hoogte stellen van gevaarlijke omstandigheden.

Ook al lag het huis van de engelen op zijn pad, de dam werd beoordeeld als een "aanzienlijk" in plaats van "hoog" gevaar, wat betekent dat het volgens de wet van Nebraska niet vereist was om een ​​formeel noodactieplan te hebben. Ongeveer 20% van de door de staat gereguleerde dammen met hoog risico in het hele land hebben nog steeds geen noodplannen, volgens het US Army Corps of Engineers, die de nationale daminventaris bijhoudt.

Bij de laatste inspectie in april 2018, De beoordeling "redelijk" van Spencer Dam ging vergezeld van een onheilspellende notatie:"Er zijn tekortkomingen die kunnen leiden tot het falen van de dam tijdens zeldzame, extreme stormgebeurtenissen."

Tim Gokie, hoofdingenieur van Nebraska's damveiligheidsprogramma, zei dat de waarschuwing te wijten was aan het doorsijpelen van water in het verleden, het elektriciteitsbedrijf aangepakt door een afvoersysteem te installeren. uiteindelijk, Gokie zei, de stijgende Niobrara-rivier overweldigde eenvoudig de betonnen en aarden dam, die in 1927 werd gebouwd om hydro-elektriciteit op te wekken, niet voor overstromingsbeheer.

"Het feit was dat het gewoon een ongekende situatie was, "Nebraska Public Power District-woordvoerder Mark Becker zei. "Het was meer dan iedereen had verwacht."

Nebraska was een van de staten die dit jaar het zwaarst werden getroffen door stormen en overstromingen die naar schatting $ 1,5 miljard aan schade aan wegen hebben veroorzaakt. dammen, nutsbedrijven en andere infrastructuur in 28 staten, volgens een AP-analyse.

Een National Climate Assessment dat vorig jaar door het Witte Huis werd vrijgegeven, wees op een toenemende frequentie en intensiteit van stormen naarmate het klimaat verandert. Dat kan sommige dammen verder drijven dan waarvoor ze zijn ontworpen.

Zelfs als het in goede staat wordt gehouden, duizenden dammen kunnen gevaar lopen door extreme regenbuien, zei Fugate, de voormalige FEMA-functionaris.

"Dit zijn net tikkende bommen die daar gewoon zitten, wachten tot de verkeerde omstandigheden zich voordoen om catastrofale mislukkingen te veroorzaken, " hij zei.

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The nation's dams are categorized as high, significant or low hazard in the National Inventory of Dams database. High hazard means loss of human life is likely if a dam were to fail. A significant rating means no deaths are likely, although economic and environmental damage are possible.

There is no national standard for inspecting dams, leading to a patchwork of state regulations. Some states inspect high-hazard dams every year while others wait up to five years. Some states never inspect low-hazard dams—though even farm ponds can eventually pose a high hazard as housing developments encroach.

Dam conditions are supposed to be rated as unsatisfactory, poor, fair or satisfactory. But the ratings are subjective—varying by state and the interpretations of individual inspectors—and are not always publicly disclosed.

Since the Sept. 11, 2001, terror attacks, the U.S. government has cited national security grounds in refusing to include dams' conditions in its inventory, which was updated most recently in 2018. But the AP was able to determine both condition and hazard ratings for more than 25, 000 dams across the country through public records requests.

The tally includes some of the nation's most well-known dams, such as Hoover Dam along the Colorado River, but mostly involves privately owned dams. Many are used for recreation.

The AP then examined inspection reports for hundreds of high-hazard dams in poor or unsatisfactory condition. Those reports cited a variety of problems:leaks that can indicate a dam is failing internally; unrepaired erosion from past instances of overtopping; holes from burrowing animals; tree growth that can destabilize earthen dams; and spillways too small to handle a large flood. Some dams were so overgrown with vegetation that they couldn't be fully inspected.

Georgia led the nation with nearly 200 high-hazard dams in unsatisfactory or poor condition, according to the AP's analysis.

Among them is Reservoir No. 1 in Atlanta, a 180 million-gallon water supply dating to the late 1800s that has been out of service much of the past few decades. The city made repairs and brought it back online in 2017, only to shut it down again after leaks were noticed.

If the dam were to catastrophically fail, the water could inundate more than 1, 000 woningen, dozens of businesses, a railroad and a portion of Interstate 75, according to an emergency action plan .

Joel Iverson has previously noticed water trickling out of the dam near the brewery he co-founded, Monday Night Brewing.

"If that one goes, it's going to wash away us and a lot of beer, " Iverson said.

The Atlanta Watershed Management Department declined the AP's request for an interview about the reservoir and instead asked for questions in writing. When those were submitted, it declined to answer them.

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One of the most common problems for aging dams are spillways incapable of handling an extreme rainfall event.

If water can't escape quickly enough through spillways, it could flow over the top of a dam, which increases the probability of rapid erosion that can cause it to collapse.

The spillway at the 107-year-old Willett Pond Dam near the Boston suburb of Norwood is capable of handling just 13% of the water flow from a serious flood before the dam is overtopped, according to a recent state inspection report. If the dam were to give way, it could send hundreds of millions of gallons of water into the heart of the city of nearly 30, 000 mensen.

"We are not talking of just flooding someone's house. We are talking about covering their house, " said Murray Beach, who lives on the shore of the 220-acre privately owned lake and belongs to a citizens group that has lobbied for years for the spillway to be repaired.

A 2017 inspection report said improvements to the spillway could cost between $1 million and $5 million. A nonprofit that owns the lake received a $215, 000 state grant last year to design spillway improvements. But there is no timeline to fix it.

meer dan 1, 300 properties lie within the dam's inundation zone, including several shopping centers and at least two elementary schools, as well as more than 70 roads and two railroads.

Tamiko Porter, who operates a Montessori school serving some 75 students, said she was surprised to learn there was a dam upstream that could flood her school if it failed.

"Oh God, please let it happen when my kids aren't here, ' zei Portier.

Norwood emergency management director Bernard Cooper said there is no imminent risk of dam failure.

"Ja, it needs work. The spillway should be rebuilt. Absolutely, no question, " Cooper acknowledged. But "there is no money in the system for that."

Concerns about inadequate dam spillways date back decades to when the Corps of Engineers undertook its first nationwide assessment of dams posing a high risk to life and property. From 1978 to 1981, the Corps inspected 8, 818 dams. About one-third were deemed unsafe due to deficiencies, and about 80% of those cited inadequate spillway capacities.

One of the dams cited for a "seriously inadequate" spillway in 1978 was Lake Sebago, located in a New York state park near the village of Sloatsburg. Veertig jaar later, nothing has changed.

A 2018 state inspection letter warned of "inadequate spillway capacity and dam stability" and asked for an improvement plan within 30 days. None was provided.

The state dam safety office has no authority to force the state parks department to make repairs.

To modify the Lake Sebago spillway, workers would have to rebuild a road and bridge that pass over the dam. The project could cost over $15 million, said Jim Hall, the recently retired executive director of the Palisades Interstate Park Commission, which manages multiple dams.

"That structure has been in place with the same spillway capacity for over probably 60 to 70 years and it hasn't been overtopped, " Hall said. "Should it be improved to meet all codes? Yeah, that would be nice. Does it make it the highest priority for us to do in relation to other dam structures we have? Probably not."

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In a 1982 report summarizing its nationwide dam assessment, the Corps of Engineers said most dam owners were unwilling to modify, repair or maintain the structures, and most states were unwilling to spend enough money for an effective dam safety program.

Vanaf dat moment, every state but Alabama has created a dam safety program.

But the Great Recession a decade ago forced many states to make widespread budget and personnel cuts. Since a low point in 2011, states' total spending on dam safety has grown by about one-third to nearly $59 million in the 2019 fiscal year while staffing levels have risen by about one-fifth, according to data collected by the Corps of Engineers.

Californië, which runs the nation's largest dam safety program, accounts for much of that gain. It boosted its budget from $13 million to $20 million and the number of full-time staff from 63 to 77 following the failure of the Oroville dam spillway in 2017.

The scare at Oroville, the nation's tallest dam, led to evacuation orders for nearly 200, 000 mensen, although no one was injured and the dam ultimately held. An independent investigation cited "a long-term systemic failure " by regulators and the dam industry to recognize and address warning signs.

California spent $1.1 billion repairing the Lake Oroville spillway, enacted new emergency plan requirements and launched a review of 93 other dams with similar spillways.

In Zuid-Carolina, after more than 70 dams failed following heavy rains in 2015 and 2016, the state tripled the personnel in its dam safety program and ratcheted up spending from about $260, 000 annually to more than $1 million.

But some states have continued to pare back their dam safety programs. Thirteen states and Puerto Rico were spending less in 2019 than they did in 2011, and 11 states had fewer full-time positions in their programs.

The Association of State Dam Safety Officials says almost every state faces a serious need to pump additional money and manpower into dam safety programs.

"If you don't have the staff to inspect a dam, or don't have the authority to do that, you don't know what the problems are, " said the association's Ogden.

"If you are able to do the inspection but you can't follow up, and you have dam owners who don't have the resources to fix their dam, then ultimately you know what the problem is but you can't get it addressed, " hij voegde toe.

Many states face a quandary when it comes to problematic private dams when they can't identify the owners. Rhode Island's two-person dam safety office last year listed 32 high- or significant-hazard dams with safety concerns whose owners were unknown.

"If we don't know the owner, then we can't take any action to order anybody to fix it, " said David Chopy, chief of compliance and inspection for the Rhode Island Department of Environmental Management.

In some states, dams go uninspected because of exemptions in state law.

A 2013 Texas law exempts all dams on private property with a capacity of less than 163 million gallons that are rated significant or low hazard and are located outside of city limits in any county with fewer than 350, 000 mensen. Als resultaat, about 45% of its roughly 7, 200 dams are exempt from regulation.

Missouri performs safety inspections on only about 650 of its more than 5, 000 dams. That's because state law exempts all dams that are under 35 feet, used for agricultural purposes or subject to federal regulation.

Former Missouri Gov. Matt Blunt attempted to significantly expand the number of dams under state supervision after the mountaintop Taum Sauk Reservoir collapsed in December 2005, injuring a state park superintendent's family. But the legislation failed after some rural landowners expressed concerns. Then the proposal quietly faded away as new officials took over.

"Maybe it's time to take a look at that again and make sure that our dams are safe, " said Missouri state Rep. Tim Remole, who now leads the House committee overseeing dam safety.

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Until Angel's death in Nebraska this year, the last fatal dam failure in the U.S. occurred on the Hawaiian island of Kauai in 2006.

An earthen wall of the Kaloko Reservoir collapsed during heavy rains and sent a wave of water rushing down a hillside. Seven people—including a pregnant woman—were killed on Bruce Fehring's property, including his daughter, son-in-law and grandson.

Fehring, who wasn't there at the time, got a phone call from a neighbor saying something terrible had happened. He was shocked by the scene.

"It took a while to register, and I went, 'Oh my God, everything's been washed away, '" Fehring recalled. "I mean, you have no idea the power of water (until) you see what it can do in a very short amount of time."

Dam owner James Pflueger pleaded no contest to felony reckless endangerment and was sentenced to seven months of confinement and five years of probation. His property company pleaded no contest to seven counts of manslaughter. Prosecutors said Pflueger had filled in the dam's spillway while attempting to make space for a waterfront development.

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The victims' families and those whose property was damaged, including actress Bette Midler, agreed to a $25 million civil settlement. Though categorized by the state as low hazard at the time it failed, Kaloko Reservoir is now listed as a high-hazard facility in poor condition . It remains largely unrepaired.

That's also the case with Lake Dunlap Dam, northeast of San Antonio. On a sunny morning in May, one of the 91-year-old dam's corroded spillway gates suddenly gave way. No one was hurt in the rush of water, but scores of homeowners' lakeside docks were left high and dry, facing barren swaths of dried lakebed after the river retreated, leaving boats stranded.

The dam was the second hydroelectric facility along the river to fail within the past three years. The Guadalupe-Blanco River Authority responded with plans to drain a chain of four lakes because of concerns their similarly designed spillway gates also could fail.

But after property owners sued, the river authority agreed in September to a temporary injunction delaying the plan for a year. That could allow time to find funding for the estimated $90 million to $210 million to repair the dams.

"This is something that communities and states all across the country are grappling with as we are reckoning with our aging infrastructure, " said Tess Coody-Anders, a homeowner near Lake McQueeney, one of the dams slated to be drained.

"I hope that everyone will recognize that, like in our community, entire economies and ways of life have developed around what started out as a civil engineering project, " she added. "And you can't take that away."

© 2019 The Associated Press. Alle rechten voorbehouden.