As development steadily encroaches on once-rural dams and reservoirs, the number of high-hazard potential structures in the US’ ageing dam population has more than doubled over the past 20 years. Estimates suggest that the number of deficient high-hazard dams now exceeds 2300. Risk is increasing, says the Federal Emergency Management Agency (FEMA), and dam safety needs to be considered on a watershed scale.
The above is one of several findings that FEMA recently published in its Dam Incident Response Review (DIRR) into the Edenville and Sanford Dam failures in Michigan.
On the evening of 19 May 2020, following several days of heavy rain, the Edenville Dam in Michigan failed. The resulting release of water subsequently also caused the failure of the Sandford Dam located downstream. As the DIRR details, this record-breaking flooding led to widespread damage and destruction of buildings, homes, roads, utility infrastructure, and natural resources. More than 4,000 structures across the region were reportedly impacted by the floodwaters, with estimated losses of roughly $245 million. Approximately 11,000 residents were successfully evacuated from the area with no serious injuries or loss of life reported.
Published in April 2022, FEMA says that the goal of the DIRR was to better understand the events leading up to the incident, the response, recovery efforts and impacts in order to highlight best practices and lessons learned.
The other findings and recommendations into the Michigan failures include:
Relationships and collaborative planning before an incident greatly impact effective communication, coordination, and response during an emergency incident.
Strong working relationships established during non-emergency times help build confidence and trust between the individuals, agencies and organisations involved in emergency response efforts. Strong relationships also promote efficient and effective communication and coordination during a rapidly developing incident. Exercises provide a valuable opportunity to test plans, to confirm roles and responsibilities, and to identify areas for improvement.
Exercises build preparedness by providing a low-risk environment to validate plans, procedures, and capabilities.
Exercises in areas with dams are particularly critical to clarify responsibilities between dam owners and the downstream communities in the event of a dam failure. Exercises can also help identify resource requirements and areas for improvement for evacuation, alert and warning notifications to vulnerable populations and other operational priorities.
Data analysis is critical for planning and for impactful post-event analysis.
Consistent, quality data are key to any analytical analysis. The better the data, the better the results and outcomes. Data is needed before an event to enhance community analysis, inundation modelling, and capability assessments. After an incident, it is important for agencies involved in data collection activities to work together to collect data in an appropriate and efficient manner to reduce duplicative efforts and preserve the “freshness” of perishable information.
Open communications with the community are essential to explain risk and to create more effective alerts and warnings for evacuations and shelter-in-place guidance.
Educating community stakeholders businesses, community organisations serving underserved populations, and the public about potential risks will help to increase compliance with instructions to evacuate or to shelter-in-place.
“While it is important to invest in maintenance, compliance, and mitigation for dams across the country,” the Michigan DIRR states, “the events of May 2020 also demonstrate the importance of investing in collaborative planning, exercises, data analysis, communicating with the public, and using watershed areas to plan across jurisdictional boundaries. Supporting local officials, emergency managers, dam owners/operators, and community members through technical assistance to build resilience for dam emergencies is an equally valuable investment to save lives.”
Safety awareness day
Held on 31 May every year in the US, Dam Safety Awareness Day is in memoriam of the 2200 people who lost their lives in the 1889 South Fork Dam failure near Johnstown, Pennsylvania. However, as FEMA warns, the South Fork Dam tragedy is not an isolated incident.
“As we observe and reflect on the South Fork Dam tragedy 133 years later, we encourage you to understand the continued importance of dam safety, the roles various parties play, current issues, and why investment in this infrastructure is urgently needed,” FEMA said. “Recent crises following heavy seasonal rains, like the failure of the Oroville Dam spillway in California (2017) or the failure of the Edenville and Sanford dams in Michigan (2020), have made major headlines, highlighting the poor condition of many of the nation’s dams. Proper maintenance, routine inspection, necessary upgrades, and implementation of an Emergency Action Plan can ensure optimal conditions, protecting public health, safety, and welfare.
“National Dam Safety Awareness Day not only commemorates the past. It calls us to action,” FEMA continued. “Dam Safety is a shared responsibility. Know your risk, know your role, know the benefits of dams and take action.”
The Baltimore District of the US Army Corps of Engineers has heeded this advice and is stressing the importance of recognising not only the benefits but also the risks of living near dams.
Baltimore District has an extensive flood risk management programme and is responsible for inspecting over 240km of levee systems and operating 16 dams, translating to the prevention of more than $16 billion of flood damages to date.
Tucked between Garrett County, Maryland, and Mineral County, West Virginia, the Jennings Randolph Lake (JRL) project (originally called Bloomington Lake) consists of a 90m high rolled earth and rockfill dam that extends almost 650m across the valley. Project functions include flood risk management, water quality, low-flow augmentation, water supply, and recreation.
Since becoming operational in 1981, JRL has prevented an estimated $400 million in potential flood damage to communities downstream. Although it reduces the risk of flooding, it does not eliminate it. Many people who live downstream of JRL are completely unaware of the potential hazard.
In order to provide the dam safety community, as well as the public, a better understanding of USACE’s efforts to reduce dam risk and promote dam safety through awareness, JRL has launched a Dam Risk Communication webpage that provides risk education as well as relevant resources for those who live near the project.
The website includes general information on JRL dam’s mission, functionality and inspections, relevant links and resources, Q&As, regional Emergency Management Agency contact information and tips for how to best prepare in case of downstream flooding.
“Public safety is the Army Corps’ top priority,” said Ken Fernandez, Jennings Randolph Lake Operations Project Manager. “JRL is authorised for multiple purposes, including recreation that we all have come to know and love. However, we must keep in mind that its primary purpose is flood risk management and with that comes risks and potential hazards to downstream communities. Dam safety is a shared responsibility, and we want those nearby to know their risk, know their role, and take action.”
Strengthen construction
Metals company Boliden is investing in strengthening current dam construction to meet international industry standards, and eventually change to a new dam construction method to ensure long-term disposal of tailings in the Aitik copper mine in Sweden.
“A high level of dam safety is always our top priority,” commented Mikael Staffas, President and CEO of Boliden. “The new direction naturally entails challenges in the short term, but it also creates long-term opportunities in Aitik and a clear direction for how the business can be developed going forward.”
Ongoing geotechnical investigations highlighted the need for a change in dam construction methods. Normally, the dam structures at Aitik’s tailings pond are built and filled in line with production, but surveys for future dam heightening identified areas with poorer soil conditions than previously estimated, which means that additional dam heightening and deposition of tailings against dams in these areas has been suspended.
In a first step, existing dam structures will now be strengthened and certain infrastructure will need to be moved. This is estimated to take about two years, after which dam heightening and deposition in this area can be resumed.
Production in Aitik is not expected to be affected during this time as tailings can continue to be deposited in other parts of the tailings pond. The measures depend on environmental permits and other approvals, but work can be started prior to the permitting process.
Ukraine dam safety
The International Commission on Large Dams (ICOLD) has voiced its concerns about dam safety in Ukraine, following the military conflict with Russia and its impacts on dams located in the country.
ICOLD President Michael Rogers said that ICOLD expresses its deepest concern for the people of Ukraine, especially concerning the safety of dams and levees there.
“ICOLD is an apolitical organisation dedicated to the peaceful technical collaboration of experts for the safety of dams and levees in all countries,” Rogers stated. “It is with heavy hearts that we watch the humanitarian crisis and destruction of property and infrastructure in Ukraine. We are concerned for the dams and levees in Ukraine that provide critical infrastructure for water, power, and flood control for all its citizens, especially the 23 large dams identified in the ICOLD Register.”
ICOLD said it brings together experts from 104 countries in peaceful collaboration for the safety of all dams and levees and that it stands in strong support of the National Hydropower Association of Ukraine for the safety of its dams and hydropower stations.
“The ICOLD family has many colleagues in Russia and Ukraine who have peacefully worked side-by-side with other global experts for many decades. It is heartbreaking to see such a conflict,” Rogers said. “ICOLD supports all our colleagues in the engineering and scientific community. As we have always done through great crises faced during our 94 years of existence, ICOLD will continue to serve the cause of peaceful dialogue between engineers and scientists in the service of critical infrastructures.
“At an appropriate time, ICOLD stands ready to provide technical support to Ukraine for the assessment and reconstruction of critical water and power infrastructure. Our heartfelt thoughts and prayers go to the millions of people in Ukraine directly impacted by this tragedy as we hope for the safety of its dams.”
Strengthening Tunisia
The World Bank has launched a new report with the Government of Tunisia, and the Global Fund for Disaster Risk Reduction and Recovery, to examine ways of improving the capabilities of Tunisia’s National Meteorological and Hydrological Services.
Tunisia is highly prone to climate-related disasters, such as floods, droughts, extreme temperatures, and sea level rise. The latest World Bank disaster risk profile of the country estimates that floods alone cause an average annual loss of US$40 million (or 0.1% of Tunisia’s 2018 GDP). Underlying factors, including climate change, population growth, land use changes, and urbanisation, increase the severity and frequency of these events.
The report, Strengthening Hydromet and Early Warning Systems and Services in Tunisia—A Roadmap proposes three successive development phases designed to transform meteorological and hydrological service providers in Tunisia into technically sound and modern entities that can meet their public service mandates. It shows that the benefits of weather, climate, and hydrological services outweigh the capital and operational costs of providing them.
“Effective hydrometeorological and early warning services will provide vital information to protect people’s lives before disaster strikes in Tunisia and promote more equitable economic growth across a wide range of sectors,” said Alexandre Arrobbio, World Bank Country Manager for Tunisia. “This new roadmap reaffirms the World Bank’s commitment to supporting the Tunisian government’s strategy to strengthen the country’s resilience to climate hazards.”
Information from the report was used in the preparation of Pillar 2 (Disaster Preparedness) of the Tunisia Integrated Disaster Resilience Programme which addresses hydromet services and the Early Warning Systems used to alert populations to impending natural disasters.
The Disaster Preparedness component is designed to bolster community resilience to climate extremes, largely by improving the capacities of Tunisia’s National Meteorological and Hydrological Services and its Dams and Hydraulic Works Department. Their systems will be revamped so they can deliver more accurate, reliable, and timely weather forecasts and other related services.
This article first appeared in International Water Power magazine.
