The way the US operates its dams across three federal agencies is “appropriate and sound” but can benefit from some areas of improvement, according to a year-long independent study to assess the use of risk-informed dam safety practices.

Triggered by broad industry concerns about dam safety following the 2017 spillway failure at California’s Oroville Dam, the US Army Corps of Engineers (USACE), alongside the Federal Energy Regulatory Commission and the Bureau of Reclamation, contracted a panel of external dam experts to review their practices at the direction of US congress.

“Many agencies including USACE took a much closer look at how we have been evaluating safety at our dams. Congress was also interested in what the Oroville incident meant for the nation and for federal dams specifically. They asked USACE to coordinate an independent review of the risk policies and methods used to assess risk across the three major federal agencies that own, operate, or regulate dams in the US. It was congress’ intent to inform improvements broadly in national dam safety practices,” explains Nate Snorteland, Risk Management Centre’s Director whose work falls under USACE’s Institute for Water Resources.

The panel included a broad range of experience and expertise, encompassed individuals from the US, the Netherlands, and Australia, and included academics and private sector consultants. In addition to evaluating agencies’ use of risk in dam safety and regulation, the panel also considered how dam safety practices are affected by human factors, as well as how risk-informed analysis in other industries may be applicable to dam safety practices.

Overall, the review showed that the programmes for dam safety in the three agencies are appropriate and sound. Additionally, the agencies’ implementation of risk-informed decision-making are consistent with federal guidance despite differing levels of dam safety programme development between them. The panel felt the level of cooperation between agencies and progress made by the agencies over the last ten years was important and had improved safety overall.

The report also highlighted issues that warrant further attention. Specifically, it was recommended that the agencies incorporate practices used in other industries more fully, such as incorporating human factors into risk methods. The team also recommended agencies fully calibrate models used in risk analyses and employ expert judgments to support safety assessments. Other recommendations of note included improving communication with the public on their risk exposure. USACE concurred with each of the recommendations and has developed a plan to implement improvements over the next several years.

“When it comes to the management of our dams, public safety is our top priority,” USACE Headquarters Dam and Levee Branch Chief, Travis Tutka, added. “USACE conducts self-assessments of our programmes and contracts external reviews periodically. Overall, the review validated our efforts with some room for improvement. By maintaining openness and transparency of our programmes with the public through reviews such as this, we hope to increase trust in our management of USACE dams on behalf of the nation.”

Better communication

ICOLD recently issued a statement in response to a short film it posted on LinkedIn by the United Nations Office for Disaster Risk Reduction (UNDRR), calling for the dismantling of old dams. The commission said that although it was pleased to see UNDRR addressing the critical issue of dam safety, it would have appreciated a slightly less simplistic analysis of the subject.

“Deconstruction is far from being the only way to address the potential safety problems posed by ageing dams,” ICOLD said.” It is even completely unrealistic on the scale of nearly 60,000 large dams according to the World Register of Dams.”

ICOLD then went on to give the examples of many dams that have given hundreds of years of “good and loyal service” which is “a little more than the 50 years mentioned by UNDRR”. It noted there are many dams built by the Romans in Spain that they are still in operation, such as the Proserpina Dam which was built in 130 of modern times under the reign of Emperor Hadrian and is still in service. While the Japanese Sayamaïke Dam, dating from the 7th century, continues to provide water storage service for the population for which it was built. In Europe, many dams were built between the 17th and 19th centuries, in particular to supply the navigation canals. They are still in service and, undergoing renovation since the 1970s, are now up to the same safety standards as modern dams. Of particular note is France’s 35m high Saint Ferréol Dam in the Montagne Noire, built in 1672 with a capacity of 6.2Mm3, which supplies water to the Canal du Midi and is a major tourist attraction.

ICOLD also noted that in 2019 it adopted, at the initiative of Michael Rogers, a World Declaration on Dam Safety, addressed to governments, funding institutions and dam operators, which sets out the essential principles of dam monitoring. If these principles are followed, there is no reason to deconstruct structures that are essential to the population. ICOLD stated that it “is in no way opposed to the deconstruction of dams when they have ceased to serve a purpose and when the economic and environmental costs of maintaining them exceed the services they can provide” but does not believe that the message that UNDRR was giving in its film, that an ageing dam is a dangerous dam and that safe dams are those that have been dismantled or deconstructed, is correct.

Denouncing the “anxiety-provoking communication” of the UNDRR, ICOLD noted that last year its President Michael Rogers wrote to the President of the United Nations University to express his willingness to work with the institution “to take a more realistic view of the problem of ageing dams”. ICOLD said it reiterates its wish to work on dam safety with all concerned institutions and believes that this very important subject deserves better communication.

Australian action

WaterNSW has announced that investigations are underway to address safety concerns and ensure the long-term security of Warragamba Dam in Australia. The dam, one of the largest domestic water supply dams in the world which supplies more than 80% of Sydney’s water, currently remains safe for day-to-day operations and is structurally sound, but is being examined in light of the potential risks posed by extreme floods and the impact of climate change on downstream communities.

WaterNSW regularly conducts risk assessments of its dams and implements upgrades as necessary to meet contemporary dam safety regulations, it said. A recent risk assessment of Warragamba Dam has identified potential climatic and geotechnical risks under extremely rare weather conditions. Although there are no immediate structural concerns regarding the dam wall, additional measures may be required to mitigate the effects of extreme floods associated with climate change, considering the large population downstream.

WaterNSW emphasised that Warragamba Dam is capable of withstanding even the most severe floods. However, in accordance with evolving safety standards and in anticipation of climate-related challenges, the organisation is committed to ensuring the dam`s compliance with the latest NSW dams` safety regulations. The specific actions, whether they involve infrastructure modifications or non-infrastructure solutions, required to address the identified risks are yet to be confirmed. Investigations are now underway to evaluate the necessary measures and guarantee the dam`s ongoing compliance with safety regulations.

Earlier in the year WaterNSW successfully restored function to critical inlet infrastructure at Lake Brewster that was extensively damaged during major flooding in late 2022. Crews working extended shifts successfully completed the most urgent repairs, including more than one kilometre of inlet channel, used to control water flow into the lake which is major water storage on the lower Lachlan River and an important pelican breeding area.

The preliminary works at Lake Brewster are only the first in what will be an extensive rehabilitation process. Initial investigations indicate that much of the embankment network at the lake has incurred some degree of damage, and aerial inspections continue in consultation with dam safety experts to better understand the scale of the repair project.

US safety concerns

The Michigan Department of Natural Resources (DNR) has embarked on a plan to address public safety and infrastructure concerns surrounding the Cornwall Flooding Dam. Earlier this year, the DNR announced its intention to draw down the impoundment behind the dam, and since then, it has been working with partners to secure funding and execute a detailed inspection. Such an inspection will enable DNR to gather comprehensive data to help identify the safest and most efficient course of action for the high-hazard dam.

Randy Claramunt, chief of the DNR Fisheries Division, stressed the crucial role of partner support and funding in determining the future of the Cornwall Flooding dam. “With additional support and more complete data, we can explore various options for high-hazard dams like Cornwall,” Claramunt stated.

Built in 1966, the Cornwall Flooding plays a significant role in the local community as an outdoor recreation spot for fishing, kayaking, and wildlife observation. It has been classified as a high hazard by the Michigan Department of Environment, Great Lakes, and Energy which means that a potential dam failure could result in severe damage to homes and infrastructure downstream, significant environmental degradation, and even loss of life.

In the absence of funding, whether internal or external, the DNR says it will still address safety concerns. Furthermore, it is currently conducting evaluations of more than 200 other state-owned dams across Michigan. These evaluations aim to determine the most prudent actions moving forward, as the agency navigates the intricate considerations of environmental impact, social implications, safety concerns, and financial constraints associated with dam ownership, maintenance, and repair.

Meanwhile, the Office of the Assistant Secretary of the Army for Civil Works and the US Army Corps of Engineers (USACE) have announced the finalisation of a rule that will establish a credit assistance programme for dam safety projects. Known as the Corps Water Infrastructure Financing Programme (CWIFP), it aims to provide financial support in the form of direct loans and loan guarantees to non-federal dam safety projects.

The CWIFP will focus on the maintenance, upgrade, and repair of dams identified in the National Inventory of Dams, accelerating investments in water resources infrastructure. By offering long-term, low-cost loans with flexible repayment options to creditworthy borrowers, it aims to enhance dam safety, promote resilience, and generate financial savings for crucial infrastructure investments.

“By expanding the tools for infrastructure financing, the programme will accelerate completion of dam safety projects nationwide.” Assistant Secretary of the Army for Civil Works, Michael Connor, said, adding that the initiative aims to support local communities and address the challenge of funding rehabilitation, improvement, and expansion of ageing civil works infrastructure, particularly dam infrastructure. The programme will prioritise projects benefiting economically disadvantaged communities, offering fee waivers and project financing of up to 80% of total project costs.

USACE believes that the scheme will help address the nation`s significant challenge in financing dam infrastructure projects, and is an innovative approach to supporting infrastructure investment while reducing reliance on federal funding. It is expected to provide approximately US$7.5 billion in total project financing, supporting up to US$15 billion in infrastructure investment nationwide.

This article first appeared in International Water Power magazine.