The Importance of Dam Safety Awareness

The Importance of Dam Safety Awareness

On May 31, 1889, the South Fork Dam near Johnstown, Pennsylvania collapsed during a large storm. The failure of this dam claimed 2,209 lives as 20 million tons of water flooded the town. Prior to the dam failure, dam safety awareness was minimal and was not widely recognized. Now, 131 years later, strong dam safety programs, investment in America’s critical infrastructure, and dedication to public-private partnerships are just as crucial. The importance of Dam Safety Awareness must continue growing to assure America’s dams are safe, resilient, and operational.

Garrison Dam – ND

Dams in America

There are more than 90,000 dams in the United States that have been built to maximize the use of our most valuable resource – water. They serve several functions including water supply for agricultural, community, domestic, and industrial use; flood control; recreation; and renewable energy.

Water Storage – Dams create reservoirs that supply water for irrigation, domestic and commercial water supply, recreation, fire control, and more.

Flood Control – Damns aid in reduced flooding and erosion.

Irrigation – Ten percent of the water used by American cropland is stored behind dams.

Renewable Energy – Dams produce 8-12 percent of the nation’s power needs via hydropower. Without hydropower, the United States would have to burn an additional 121 million tons of coal, 27 billion barrels of oil, and 741 billion cubic feet of natural gas.

Recreation – Boating, fishing, swimming, and camping are just some of the recreational activities that take place as a result of hydropower created by dams.

Dam Safety Issues in America

Safe operation and maintenance of dams are critical when it comes to avoiding potential dam failure and disaster. With tens of thousands of dams across the country, many of which are approaching their life expectancy, it’s important to be on the lookout for dams with high-hazard potential. High-hazard potential dams climbed to more than 15,000 in 2018, and only continue to grow due to growing populations. This increase is known as ‘hazard creep’. Hazard creep describes the growth of development such as people, buildings, and businesses, that moves closer to dams.

Investing in Dams

Dams are a major piece of our country’s critical infrastructure, and investment is needed to rehabilitate those that are deficient.

Dam on the Green River, upstream from the Green River Covered Bridge, near Brattleboro, Vermont.

Why do dams need upgrading?

  • Deterioration
  • Changing technical standards over time
  • Improved techniques for building
  • Increases in population
  • Better understanding of precipitation patterns in areas
  • Changing land use

Upgrading a dam when it reaches an increased hazard potential is critical for the integrity of the dam structure as well as the safety of those living in the vicinity. The problem that dam owners have (especially on the private side) is the difficulty in funding the upgrades.

The Association of State Dam Safety Officials have tracked dam rehabilitation costs for non high-hazard and high-hazard dams since 2004.

Recreational Dam Safety Awareness

Outside of critical infrastructure, dams provide recreational opportunities for boaters, swimmers, kayakers and more. Unfortunately, there are dozens of deaths on American waterways each year that take place at structures called ‘low-head’ dams.

Low-head dams are low in height and typically have a 1-15 foot drop off, allowing water to flow off the dam. Below the drop off, water falling from the dam can create circulating currents that can trap people and objects underwater against the face of the dam. The force of the water is extremely strong, and these structures have earned the title of ‘drowning machines.’

Many people are unaware of the dangers associated with dams which is why it is so important to educate communities of dam safety.

Click here to learn more about public safety around dams.

Dam Safety Awareness Commemorates an Epic Flood

Dam Safety Awareness Commemorates an Epic Flood

The Johnstown Flood of 1889

It had been raining heavily for several days in late May of 1889.  People living below in the narrow Conemaugh Valley were eager for the spring rains to end. Just a month earlier, deep snow had lined the steep ravines of the Allegheny Mountains range and the ground was sodden with the heavy spring runoff. Floodwaters at the South Fork Dam high above the City of Johnstown, Pennsylvania were causing the lake level to rise, threatening to overtop the large earth embankment dam.

Before the dam breachAs the spring rains continued, life was about to change for the working-class city of 30,000 and other communities beneath the South Fork Dam.

Originally constructed in 1852, the South Fork Dam provided a source of water for a division of the Pennsylvania Canal. After a minor breach in 1862, the dam was hastily rebuilt creating Lake Conemaugh. By 1881, the dam was owned and maintained by the South Fork Fishing and Hunting Club, who created a recreational area by the large lake, enjoyed by their elite clientele from nearby Pittsburgh.

Lake ConemaughFor the pleasure of their private members, club owners soon began modifications to the dam. Fish screens were installed across the spillway to keep the expensive game fish from escaping. The dam was lowered by a few feet so that two carriages could navigate the carriage road to the clubhouse. Relief pipes and valves that controlled the water level and spill off from the original dam were sold off for scrap, and rustic cottages were built nearby.

Ignored Warnings

Notoriously leaky, repairs to the earthen dam had been neglected for years.  As torrential rains came down, swollen waters from the lake put tremendous pressure on the poorly maintained dam. With fish screens trapping debris that kept the spillway from flowing and with no other way to control the lake level, the water kept rising.

Aftermath of floodClub officials struggled to reinforce the earthen dam, but it continued to disintegrate. When the lake’s water began to pour over the top, it was apparent that a catastrophic collapse was inevitable and imminent.  Frantic riders were sent down the valley to alert the local communities and tell them to evacuate.  Sadly, few residents heeded the alarm being so often used to the minor seasonal flooding from the Little Conemaugh river.

This time, however, the flood danger was much more serious and deadly.

On May 31, 1889 at 3:10pm, the South Fork Dam washed away, leaving a wake of destruction that killed 2,209 people and wiped the City of Johnstown off the map forever. It took only 10 minutes for the raging torrent of 20 million tons or about 4.8 billion gallons of water to rip through the communities of South Fork, Mineral Point, Woodvale, and East Conemaugh.

Along the way, the deluge accumulated everything in its path, including all sorts of debris—from city buildings, houses, and barns. Piles of boulders, trees, farm equipment, rolls of barbed wire, horse carriages, and railroad cars churned in the turmoil. Embroiled in the devastation were also animals and people—both dead and alive.

By the time the raging waters reached Johnstown at 4:07 pm, the mass of debris was a wave 45-feet-tall, nearly a half mile wide and traveling at 40 miles per hour.

Despite the shocking immensity of this tragedy, relief efforts to the ravaged communities began almost immediately. Emergency shelters for homeless residents popped up and the grim task of cleaning up began.  Volunteers and donations poured in from across the country and world, sending tons of supplies and help. One of the first to arrive was Clara Barton, who had founded the American Red Cross just a few years earlier.

aftermathIt would take months to sift through all the wreckage to find the bodies and years to fully recover from the aftermath.

Lessons Learned

It is widely thought the South Fork Fishing and Hunting Club was to blame for the catastrophic failure of the South Fork Dam. Members of the club neglected to properly maintain the dam and made numerous dangerous modifications. Lowering the dam crest to only about four feet above the spillway severely impaired the ability of the structure to withhold stormwater overflow. The missing discharge pipes and relief valves prevented the reservoir from being drained for repairs and the elaborate fish screens clogged the spillway with debris. The club had also been warned by engineers that the dam was unsafe.

flood damageA hydraulic analysis published in 2016 confirmed what had long been suspected, that the changes made to the dam by the South Fork Fishing and Hunting Club severely reduced the ability of the dam to withstand major storms.1

The South Fork Dam was simply unable to withstand the large volume of stormwater that occurred on that fateful day on May 31, 1889.

Although the South Fork Fishing and Hunting Club failed to maintain the dam, club members were never legally held responsible for the Johnstown Flood after successfully arguing that the disaster was an “act of God.”

Due to what many perceived as an injustice and outrage towards the wealthy club members, American law was ultimately challenged and “a non-negligent defendant could be held liable for damage caused by the unnatural use of land”. This legal action eventually imposed laws for the acceptance of strict liability for damages and loss.

National Dam Safety Awareness Day

On May 31st, we commemorate the catastrophic failure of the South Fork Dam by recognizing this day as National Dam Safety Awareness Day.

The Johnstown flood or the Great Flood of 1889, as it was later known as, was the single deadliest disaster in the U.S at the time. This tragedy, 129 years later, is still a harsh reminder of the critical importance of the proper maintenance and safe operation of dams.

Earth embankment dams may fail due to overtopping by flood water, erosion of the spillway discharge channel, seepage, settling, and cracking or movement of the embankment.

Routine dam evaluations and inspections, as required by law, can identify problems with dams before conditions become unsafe.  Dams embankments, gatehouses and spillways, like other structures, can deteriorate due to weather, vandalism, and animal activity.  Qualified engineering firms can perform soil borings, soil testing, stability analyses, hydrologic and hydraulic modeling for evaluating spillway sizing and downstream hazard potential, arrange for under water inspections by divers, permitting, and assistance in applying for funding for repairs. Also required, are Emergency Action Plans (EAP) that identifies potential emergency conditions and specifies preplanned actions to be followed in the case of a dam failure to minimize property damage or loss of life.

The required frequency of dam inspections will vary depending on the state, but generally are based on hazard classification, with high hazard dams requiring more frequent inspection.   Generally dam inspections should be performed every two years for high hazard dams, unless the state requires more frequent inspections.  The best time of year for inspections is in the fall, when reservoir levels are typically low, and when foliage and tree leaves are reduced, allowing improved visibility around the dam.

A wealth of information on dam safety awareness, can be found at the Association of State Dam Safety Officials website

 

 

 

1Wikipedia.com

 

The High Cost of High-Hazard Dams

ASCE-report-cardIt is well known that our nation’s infrastructure is in desperate need of repair or replacement. In fact, the American Society of Civil Engineers (ACSE) 2017 Report Card has given our country’s infrastructure an overall grade of D+. Dams are a part of that critical infrastructure, and they have received an abysmal D grade from ASCE. We have over 90,000 dams in our country, and the average age of these dams is 56 years old. Considering that dams built 50 years ago were not designed for current standards and usually have inadequate spillway capacity, these numbers are concerning.

Even more alarming, America has nearly 15,500 high-hazard dams, with over 2,170 of these being deemed deficient. A dam is rated high-hazard when dam failure could result in the loss of human life, and deficient when it is at serious risk of failure. A deficient, high-hazard dam is a tragedy waiting to happen. Also, considering the estimated cost to repair these deficient, high-hazard dams is almost $45 billion, it is apparent that we have a dam crisis on our hands.

About Dams

Lake Mead, impounded by the Hoover Dam, is one of the most popular vacation spots in the country.

Dams provide significant economic and social benefits to society, including flood control, water storage, irrigation, debris control, and navigation. In addition, around 3% of our nation’s dams provide hydroelectric power — a clean, renewable energy source — accounting for 35% of our country’s renewable energy and 10% of our total power needs. And, of course, the most frequent function of dams is recreation. Dams impound eight of the top ten most popular vacation lakes in the United States, accounting for millions of tourist dollars and some of our country’s most beautiful and enjoyable areas.

mill-river-dam-flood
The Mill River Dam collapse was the first manmade dam disaster and one of the worst of the 19th century. On May 16, 1874, the Mill River Dam in Williamsburg, MA failed, killing 139 people and wiping out four towns in western Massachusetts within one hour.

Catastrophic dam failures have occurred in the United States for well over a century, resulting in the deaths of thousands of people and causing millions of dollars in damages. This year, we narrowly avoided a disaster when California’s Oroville Dam stabilized after threatening to fail. During the crisis, over 188,000 people were displaced due to mandatory evacuations of the area. Although the Oroville Dam crisis thankfully ended without loss of life, the cost to repair the spillway is estimated to be $275 million. In 2003, the Silver Lake Dam in Michigan failed, causing approximately $100 million in property damages and putting over a thousand miners out of work. In 2004, the Big Bay Lake Dam in Mississippi failed, destroying 48 homes and seriously damaging 53 others. In 2006, the Ka Loko Dam in Hawaii failed, killing seven people and releasing nearly 400 million gallons of water, causing significant property and environmental damage.

dam-map-ma
Click on the image for an interactive map of dams in Massachusetts.

High-hazard dams are cause for concern in every state in the nation. In Massachusetts, 1,453 dams are included in the National Inventory of Dams, 333 of which are high-hazard. Of those, about 50 are classified as “poor” or “unsatisfactory” and in urgent need of repair. If any of these dams were to fail, there is a high likelihood that there would be a loss of human life. Dam failure is most frequently caused by overtopping, accounting for 34% of all dam failures. Causes of overtopping include inadequate spillway design, blocked spillways, settlement of the dam crest, and floods exceeding dam capacity. Other causes of dam failure include foundation defects such as slope instability and settlement (30%); piping, resulting in internal erosion caused by seepage (20%); and other causes including structural failure of materials, settlement and resulting cracking, poor maintenance, and acts of sabotage (16%).

Safety Programs

oroville-dam-damage
Draw down and cut off of releases from the damaged spillway at Oroville Dam. Taken on Feburary 27, 2017. Dale Kolke/California Delpartment of Water Resources.

The National Dam Safety Program (NDSP) was signed into law in 1996. NDSP was established to improve safety and security around dams by providing assistance grants to state dam safety agencies to assist them in improving their regulatory programs; funding research to enhance technical expertise as dams are built and rehabilitated; establishing training programs for dam safety inspectors; and creating a National Inventory of Dams. Every state in the nation excepting Alabama has a dam safety program, and 41 states also have Emergency Action Plan (EAP) requirements. A detailed and up-to-date EAP is critical to a successful dam safety program for high-hazard and significant-hazard dams. States without EAP requirements are Alabama, Georgia, Illinois, Iowa, Kentucky, North Carolina, Vermont, Wyoming, and — believe it or not — California.

Unfortunately, about one-third of our nation’s high-hazard dams lack an EAP. In addition, state dam safety programs are sorely underfunded and understaffed, and many of our nation’s deficient dams are not being repaired or rehabilitated in a timely manner. Why? State dam safety programs provide the inspection, permitting, recommendations, and enforcement authority for 80% of our nation’s dams, yet the average ratio of dams to dam safety inspectors is 207:1. Also, about two-thirds of our nation’s dams are privately-owned. Without enforcement of repair recommendations, some dam owners simply choose not to sink any money into their deficient dam.

kaloko-dam
The Ka Loko Dam breach in Hawaii resulted in the deaths of seven people, including a pregnant woman and a toddler.

For example, the Ka Loko Dam in Hawaii was privately-owned, and owner James Pflueger was sentenced to seven months in prison in exchange for a plea of no contest to reckless endangering. By entering the plea, prosecutors agreed to drop the seven counts of manslaughter. But admittedly, the dam failure was the result of a series of negligent events. The State of Hawaii, like most states in the nation, had a shortage of dam inspectors, and the Ka Loko Dam had not been adequately inspected. Also, Pflueger performed unpermitted construction activities at the dam, including grading and filling in the spillway. The County of Kauai ordered Pflueger to cease and desist all illegal grading operations, yet Pflueger ignored the order with help from then-Mayor Maryann Kusaka, who served as mayor of Kauai from 1997-2004. He also knew that there was seepage at the dam prior to the failure.

Key Issues 

The Wachusett Dam in Clinton, MA is a high-hazard dam, rated in satisfactory condition.

Clearly, the Ka Loko Dam failure was due to gross negligence and was completely avoidable. To avoid similar tragedies in the future, all of the key issues facing our nation’s dams should be addressed. First and foremost, our country needs to invest in infrastructure and to prioritize funding of dam safety programs. It is imperative that dam safety agencies have adequate personnel and resources to enforce inspection, repair, and rehabilitation recommendations. Also, since two-thirds of our nation’s dams are privately-owned, lack of funding for private dam upgrades is a huge problem. Adequate maintenance and rehabilitation of dams is costly, ranging from thousands to millions of dollars, and many private owners simply cannot afford these costs. Because of the high risk of high-hazard dams, our nation must prioritize funding assistance and loan programs to both public and private owners. It is also crucial that high-hazard dams have an up-to-date EAP, including action plans as well as notification and evacuation procedures, so that authorities are prepared and residents living downstream of the dam are protected. And speaking of residents, public outreach and awareness may be the most critical component of dam safety and awareness. The typical American citizen has no understanding of the role that dams play in our lives, or of the devastation that could come about from a dam failure. Even developers and officials are often in the dark about dams in their own communities. And, of course, everyone needs to understand that all high-hazard dams, no matter how seemingly structurally sound, are potentially dangerous and that there is inherent risk living in a dam break flood-prone area. Also, many of the private dam owners in our country are largely unaware of both their responsibility toward residents and businesses located downstream of their dam and of proper dam maintenance and repair procedures.

In Conclusion

We must change the way we manage our nation’s dams in order to prevent future catastrophes. The recent Oroville Dam crisis should serve as a warning to residents and legislators. As our dams age and climate change increases severe weather events, we must invest in the oversight, funding, and awareness of this critical infrastructure. Until we do, events such as the Oroville Dam crisis and the Ka Loko Dam failure may occur with increasing frequency, resulting in loss of life, environmental damage, and economic disaster.