Dam Safety and the Criticality of Emergency Action Plans

Devastation from the Ka Loko Reservoir Dam breach in 2006

This month marks the ten year anniversary of Hawaii’s Ka Loko Dam failure on the island of Kauai. On March 14, 2006, after 40 days of heavy rainfall, the rising water finally overtopped the dam near the original spillway — which had been filled in by the owner. At the time, the State of Hawaii lacked resources and legal authority to properly ensure that the owner fully addressed safety concerns. The break sent almost 400 million gallons of water downstream four miles until it finally reached the ocean, and the water reached about 20 feet in height, destroying whatever was in its path, including trees, homes, and vehicles. The disaster, which was entirely preventable, killed seven people, including a pregnant woman and child, and caused millions of dollars of property damage as well as significant environmental damage. As a direct result of the disaster, Hawaii increased funding to its dam safety program, allowing for improved regulation of local dams.

Historic U.S. Dam Failures and Legislation

Unfortunately, the Ka Loko Dam failure in Hawaii was not an isolated incident. Dam failures in the United States have caused catastrophic damage and loss of life for well over a century:

Aftermath of the 1874 Mill River Flood in Williamsburg, MA
Aftermath of the 1874 Mill River Flood in Williamsburg, MA

May 16, 1874 – Williamsburg, Massachusetts
At 7:20 a.m., the 43-foot-high Mill River Dam above Williamsburg, Massachusetts failed, killing 138 people, including 43 children under the age of ten. At the time, this failure was the worst in U.S. history.

May 31, 1889 – Johnstown, Pennsylvania
Over 2,200 people — more than 20% of the residents of Johnstown — perished in the flood caused by the failure of South Fork Dam, nine miles upstream. To this day, the South Fork Dam disaster is the worst in U.S. history. National Dam Safety Day is celebrated each May 31 in remembrance of the catastrophe.

Around the turn of the century, many more dam failures occurred, resulting in the passing of some early state dam safety legislation.

March 12,1928 – San Francisquito Canyon, California
The failure of St. Francis Dam, which killed over 450 people and caused over $13 million in damage, the equivalent of about $180 million by today’s standards, was a landmark event in the history of state dam safety legislation, spurring legislation not only in California, but in neighboring states as well. It was also the worst civil engineering disaster of the 20th century, serving as the catalyst for the engineering licensure requirement in California.

Only one small section of the St. Francis Dam remained after its catastrophic failure in 1928
Only one small section of the St. Francis Dam remained after its catastrophic failure in 1928

In response to the St. Francis Dam disaster, the California legislature created an updated dam safety program and eliminated the municipal exemption. In addition, the State was given full authority to supervise the maintenance and operation of all non-federal dams. However, even in the wake of such a horrific disaster, most other states had severely limited dam safety laws — that is, until a series of dam failures and incidents occurred in the 1970s:

February 26, 1972 – Buffalo Creek Valley, West Virginia
The failure of a coal-waste impoundment at the valley’s head took 125 lives, and caused more than $400 million in damages, including destruction of over 500 homes.

June 9, 1972 – Rapid City, South Dakota
The Canyon Lake Dam failure took an undetermined number of lives (estimates range from 33 to 237). Damages, including destruction of 1,335 homes, totaled more than $60 million.

June 5, 1976 – Teton, Idaho
Eleven people perished when Teton Dam failed. The failure caused an unprecedented amount of property damage totaling over $1 billion.

July 19-20, 1977 – Laurel Run, Pennsylvania
Laurel Run Dam failed, killing over 40 people and causing $5.3 million in damages.

Damage from the Toccoa Falls, Georgia dam failure in 1977
Damage from the Kelly Barnes Dam in Toccoa, Georgia dam failure in 1977

November 6, 1977 – Toccoa Falls, Georgia
Kelly Barnes Dam failed, killing 39 students and college staff and causing about $2.5 million in damages.

In response to these tragedies, President Jimmy Carter implemented the “Phase I Inspection Program” that directed the US Army Corps of Engineers to inspect the nation’s non-federal high-hazard dams. The findings of the inspection program, which lasted from 1978-1981, were responsible for the establishment of dam safety programs in most states, and, ultimately, the creation of the National Dam Safety Program, which today supports dam safety programs in 49 states. Alabama is the only state in the nation that has yet to pass dam safety legislation, although Alabama State Representative Mary Sue McClurkin introduced a bill on March 18, 2014 which, if passed, would establish a state dam safety program.

Emergency Action Plans

One of the key components of a successful dam safety program for high hazard and significant hazard dams is a comprehensive, up-to-date Emergency Action Plan (EAP). Hazard level does not reflect the condition or age of the dam; rather, it indicates the potential for loss in the event of dam failure. According to FEMA, the classifications are as follows:

High hazard: Facilities where failure will probably cause loss of human life. Such facilities are generally located in populated areas or where dwellings are found in the flood plain and failure can reasonably be expected to cause loss of life; serious damage to homes, industrial and commercial buildings; and damage to important utilities, highways, or railroads.

Significant hazard: Facilities where failure would likely not result in loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. Such facilities are generally located in predominantly rural areas, but could be in populated areas with significant infrastructure and where failure could damage isolated homes, main highways, and minor railroads or disrupt the use of service of public utilities.

Low hazard: Facilities where failure would result in no probable loss of human life and low economic and/or environmental losses. Such facilities are usually located in rural or agricultural areas where losses are limited principally to the owner’s property or where failure would cause only slight damage to farm buildings, forest and agricultural land, and minor roads.

Map courtesy of James S. Halgren, Office of Hydrologic Development, National Weather Service, National Oceanic and Atmospheric Administration
Map courtesy of James S. Halgren, Office of Hydrologic Development, National Weather Service, National Oceanic and Atmospheric Administration

Unfortunately, about 22% of high hazard dams and 40% of significant hazard dams nationwide still do not have EAPs, meaning that thousands of dams across the United States lack EAPs required by law. And dams are still failing. According to the Association of State Dam Safety Officials, 173 dams across the United States have experienced failures since 2005.

The lack of an EAP could be problematic in the event of dam failure, said Mark Ogden, project manager for the Association of State Dam Safety Officials, who also noted that while such worst-case scenarios are rare, they have happened. “An exercised, well-prepared emergency action plan is a valuable tool to help save lives,” Ogden said.

Ogden also noted that even when dams have an EAP, downstream residents often do not know where to find it. “There have been a lot of efforts in recent years to try to make the public aware of dams and the potential dangers, and to know if they live in an area downstream of a dam, the failure inundation zone, who to talk to – whether it’s the dam owner or more likely the local emergency management officials – to find out if there is an EAP for that dam and what they would need to do,” Ogden said.

Legislation

The Saville Dam in Barkhamsted, Connecticut is rated high hazard
The Saville Dam in Barkhamsted, Connecticut is rated high hazard

The good news is that most states have responded to the need for dam safety regulations and require EAPs for high hazard and significant hazard dams. The most recent legislation came in February of this year, when the State of Connecticut Department of Energy and Environmental Protection (DEEP) adopted new regulations concerning the preparation and update of EAPs for Class C and Class B dams. In 2013, fewer than 60% of regulated high hazard dams in Connecticut had an EAP, a statistic the State is hoping to drastically improve. The new EAP regulations include criteria for inundation mapping, dam monitoring procedures, formal warning notification and communication procedures, emergency termination protocols, and EAP review and revisions.

Currently, the only states without EAP requirements are Georgia, Illinois, Iowa, Kentucky, North Carolina, Vermont, Wyoming, and — ironically enough — California. Since Alabama still has no formal dam safety program, they also do not require EAPs.

Lake Martin in Alabama was created by the construction of the Thomas Wesley Martin Dam, which stopped the flow of the Tallapoosa River just southwest of Dadeville. It is the largest man-made lake in Alabama.
Lake Martin in Alabama was created by the construction of the Thomas Wesley Martin Dam, which stopped the flow of the Tallapoosa River just southwest of Dadeville. It is the largest man-made lake in Alabama.

ASDSO continues to work alongside the American Society of Civil Engineers (ASCE), American Council of Engineering Companies (ACEC), and other stakeholders to promote dam safety and to encourage legislation to protect the public and the environment from disasters such as the Ka Loko Dam failure in Kauai, Hawaii.

“The tenth anniversary of the dam’s failure reminds us of the potential dangers posed by dams and the critical importance of both responsible dam ownership and strong dam safety programs,” said Lori Spragens, executive director of the Association of State Dam Safety Officials (ASDSO). “Most dam failures are preventable disasters. Dam owners must keep their dams in the state of repair required by prudence, due regard for life and property, and the application of sound engineering principles. The quality of dam maintenance, emergency planning, and enforcement programs directly affects the safety of communities, as sadly demonstrated on Kauai. With more than 87,000 dams of regulatory size in the U.S., we all have a stake in dam safety.”

CT DEEP Issues New EAP Requirements for Class C and Class B Dams

Class C Bronson E. Lockwood Dam, Bethlehem, CT
Class C Bronson E. Lockwood Dam, Bethlehem, CT

The State of Connecticut Department of Energy and Environmental Protection (DEEP) recently adopted Regulation 22a-411a concerning the preparation and update of Emergency Action Plans (EAPs) for High Hazard (Class C) and Significant Hazard (Class B) dams.  EAPs meeting the new requirements for Class C dams must be submitted to DEEP within 12 months of February 3, 2016, the effective date of the new regulation, and within 18 months for Class B dams. Dam owners will be required to submit an updated EAP every two years thereafter, or more frequently as necessary to reflect significant changes to the dam structure or downstream area.

An EAP is intended to be a pragmatic document that both identifies conditions that require a response and provides clear instructions in an emergency situation.  “The new requirements for dam owners minimize the potential for dam failures and increase public safety by directing owners to improve oversight and responsibility for their dams through the preparation of Emergency Action Plans (EAPs) and regular inspections,” said DEEP Commissioner Robert Klee.

The new EAP regulations include criteria for inundation mapping, dam monitoring procedures, formal warning notification and communication procedures, and EAP review and revisions. Copies of the EAP must be filed with the DEEP, the chief executive officer, and the emergency management officer of any municipality that would potentially be affected by an emergency involving the dam for which the EAP has been prepared.

For more information, or for assistance meeting the new requirements for Dam EAPs, please contact us.

Dam Safety in the United States

What are dams?

Oroville Dam is an earthfill embankment dam on the Feather River east of the city of Oroville, California and is the tallest dam in the country.
Oroville Dam is an earthfill embankment dam on the Feather River east of the city of Oroville, California and is the tallest dam in the country.

In general terms, a dam is any structure that obstructs or converts the flow of water in rivers and streams, and they frequently serve more than one purpose. Dams store water to compensate for fluctuations in river flow, and they also provide irrigation, hydropower, drinking water, flood control, and support for recreational activities. There are four main types of dams, and dams are often a combination of these different types:

Embankment
Embankment dams are typically constructed from natural earth materials such as rock and compacted soil, and are therefore far less expensive than concrete dams. Therefore, not surprisingly, more than 80% of all large dams in the United States are embankment dams. Typically used to retain water across wide rivers, embankment dams have a triangular profile and an impervious core and are termed “earthfill” or “rockfill” depending on whether they are primarily comprised of earth or rock.

Gravity
Gravity dams are constructed of concrete or stone masonry and span narrow river valleys with firm bedrock. They are designed to hold back water by simply using the weight of the dam alone to resist the horizontal water load pushing against it. Each section of the gravity dam is stable on its own, independent of any other dam section.

hoover_dam_arch_gravity_dam
The Hoover Dam is a massive arch-gravity dam that was constructed during the Great Depression, and the project’s success helped usher several decades of major water projects funded by the U.S. government.

Arch
While arch dams are also constructed of concrete, they differ from gravity dams in that they are designed to transfer water loads to adjacent rock formations. Arch dams are constructed only in narrow canyons with strong rock walls that are able to resist the arch pressure at the foundation and sides of the dam. Arch dams are thin and require less material than any other type of dam.

Buttress
Buttress dams are hollow gravity dams with a solid upstream side that is supported by a series of buttresses on the downstream side. Constructed of reinforced concrete, buttress dam walls are straight or curved and are extremely heavy, pushing the dam into the ground.

Dams in the U.S.

In the United States, there are approximately 84,000 dams. The average age of these dams is 52 years old, and by 2020, over 70% of our nation’s dams will be over 50 years old, which is the widely-accepted longevity of most dams. In addition, the number of high-hazard dams, which are dams whose failure would likely cause the loss of life, is on the rise. Currently there are over 14,000 high-hazard dams nationwide, with another 13,000 being labeled significant-hazard, meaning their failure would cause significant economic loss. There are over 4,000 deficient dams, meaning they are at serious risk of failure, and 2,000 of these deficient dams are also high-hazard. The cost to repair these dangerous dams is estimated to be about $21 billion.

Many of our dams were originally constructed as low-hazard dams, which have more lenient design criteria due to their location in non-developed areas, typically agricultural. However, with the nation’s population growth and extensive development, these dams are now located in populated areas and considered high-hazard. This trend is expected to continue as population steadily increases.

The Johnstown Flood, known as the Great Flood of 1889, occurred on May 31, 1889 after the catastrophic failure of the South Fork Dam on the Little Conemaugh River 14 miles upstream of the town of Johnstown, PA. The dam broke after several days of extremely heavy rainfall, unleashing 20 million tons of water from the reservoir known as Lake Conemaugh. With a flow rate that temporarily equalled that of the Mississippi River, the flood killed 2,209 people. National Dam Safety Day is celebrated on May 31 every year in memory of this flood.
The Johnstown Flood occurred on May 31, 1889 after the catastrophic failure of the South Fork Dam on the Little Conemaugh River 14 miles upstream of the town of Johnstown, PA. The dam broke after several days of extremely heavy rainfall. With a flow rate that temporarily equalled that of the Mississippi River, the flood killed 2,209 people and decimated the town (Main Street shown in photo). National Dam Safety Day is celebrated on May 31 every year in memory of this flood.

The federal government owns only 3,225 — about 4% — of our nation’s dams. The remaining dams, over two-thirds of which are privately owned, fall under the jurisdiction of state dam inspection programs, with no federal oversight or regulation. State dam safety programs provide the permitting, inspection, and recommendations, along with enforcement authority, for 80% of our nation’s dams. Only one state, Alabama, completely lacks a dam safety regulatory program, but the rest are sorely underfunded and understaffed. For example, the average number of dams per dam safety inspector is 207. It is indeed daunting that dam safety programs are largely responsible for public safety, yet lack the resources to effectively provide that safety.

What causes dam failure?

  • Overtopping causes 34% of all dam failures. Inadequate spillway design, blocked spillways, settlement of the dam crest, and floods exceeding dam capacity are all causes of overtopping.
  • Foundation defects such as slope instability and settlement cause about 30% of all dam failures.
  • Piping, resulting in internal erosion caused by seepage, causes 20% of all U.S. dam failures.
  • The remaining 16% of dam failures are the result of other causes including structural failure of materials, inadequate maintenance, settlement and cracking, and deliberate acts of sabotage.

What can we do?

Of the 14,726 high-hazard dams in the country, only 8,854 have EAPs in place
Of the 14,726 high-hazard dams in the country, only 8,854 have EAPs in place

The 2010 Iowa Lake Delhi dam failure cost our economy about $170 million between damages and economic losses, and the 2006 Kaloko Reservoir Dam failure in Hawaii killed seven people. To make matters worse, the Kaloko dam was over 100 years old and had never once been inspected prior to its failure. Our dams have been given a “D” rating from the American Society of Civil Engineers (ASCE) 2013 Infrastructure Report Card, and the ASCE has recommended steps to take to improve that rating, one of which is the development of Emergency Action Plans (EAPs) for 100% of our nation’s high-hazard dams by 2017. Only 66% currently have EAPs.

Having effective EAPs at all high-hazard, and most significant-hazard, dams in the United States is the most important step in reducing the risk for loss of life and property damage from dam failures, and it is absolutely critical that deficient high-hazard dams have updated EAPs in place. To that end, Tata & Howard has been working with the Connecticut Department of Energy and Environmental Protection (CT DEEP) this spring to perform over 40 dam inspections and update over 30 EAPs.

T&H VP Sal Longo, P.E., assisted CT DEEP with the inspection of over 40 dams this spring.
T&H assisted CT DEEP with the inspection of over 40 dams this spring. Shown above is Vice President Sal Longo, P.E., during an inspection.

Besides maintaining EAPs for high-hazard dams, ASCE recommends the following steps to address our nation’s dam infrastructure:

  • Reauthorize and fully fund the National Dam Safety Program (NDSP), which is a partnership of the states, federal agencies, and other stakeholders that encourages individual and community responsibility for dam safety.
  • Establish a national dam rehabilitation and repair funding program to cost share repairs to publicly owned, nonfederal, high-hazard dams.
  • Implement a national public awareness campaign to educate individuals on the location and condition of dams in their area.
  • Encourage incentives to governors and state legislatures to provide sufficient resources and regulatory authorities to their dam safety programs.
  • Require federal agencies that own, operate, or regulate dams to meet the standards of Federal Guidelines for Dam Safety.

In addition to local and federal oversight and regulation, there are a number of steps that the public can take to minimize the risks associated with dam failure:

  • Know your risk. Find out if you live in a dam breach inundation zone by contacting your local emergency management agency or by contacting your state dam safety program (www.damsafety.org).
  • Know your role. Know the dams in your area where you live and work, and be aware of potential maintenance issues and report them to authorities immediately. Dam owners have the responsibility to maintain their dams and to have an EAP, especially for high-hazard dams, and should work with the federal or state regulator to comply with safety standards.
  • Take action. Inform your friends and neighbors about the benefits and risks associated with dams and have an evacuation route in place for your family and/or business should a dam fail. If you live below a dam, it is imperative that you maintain flood insurance.

In conclusion

Dams are an integral part of our infrastructure, providing many important benefits. A large percentage of our nation’s dams are in need of repair and updating, and our high-hazard dams are of particular concern. It is critical that all of us, including the federal government, states, communities, engineers, and private dam owners, work together to promote dam safety and education. Our future depends on it.

For more information on dam safety, please visit https://www.fema.gov/dam-safety#

www.scientificamerican.com
www.encyclopedia.org
www.harimurti.blogspot.com
www.infrastructurereportcard.org
www.damsafety.org
www.americanprogress.org