Dam Safety Overview and the Federal Role

October 24, 2019 – April 13, 2023 R45981

Dam Safety Overview and the Federal Role
April 13, 2023
Dams provide various services, including flood control, hydroelectric power, recreation,
navigation, and water supply, but they require maintenance, and sometimes rehabilitation and
Anna E. Normand
repair, to ensure public and economic safety. Dam failure or incidents can endanger lives and
Analyst in Natural
property, as well as result in loss of services provided by the dam. Federal government agencies
Resources Policy
reported owning 3% of the more than 91,000 dams listed in the National Inventory of Dams

(NID), including some of the largest dams in the United States. (Thousands more dams fall
outside the definition for NID inclusion.) The majority of NID-listed dams are owned by private

entities, nonfederal governments, and public utilities. Although states have regulatory authority
for over 71% of NID-listed dams, the federal government plays a key role in dam safety policies for both federal and
nonfederal dams.
Congress has expressed interest in dam safety over several decades, often prompted by critical events such as the 2017 near
failure of Oroville Dam’s spillway in California and the 2020 failure of two hydropower dams in Michigan. Dam failures in
the 1970s that resulted in the loss of life and billions of dollars of property damage spurred Congress and the executive
branch to establish the NID, the National Dam Safety Program (NDSP), and other federal activities regarding dams. These
programs and activities have increased safety inspections, emergency planning, and dam rehabilitation and repair. Since the
late 1990s, some federal and state dam safety programs have shifted from a standards-based approach to a risk-management
approach. A risk-management approach seeks to mitigate failure of dams and related structures by conducting comprehensive
inspections, enacting risk reduction measures, and prioritizing rehabilitation and repair of structures whose failure would
pose the greatest threat to life and property.
Responsibility for dam safety is distributed among federal agencies, nonfederal agencies, and private dam owners. The
Federal Emergency Management Agency’s (FEMA’s) NDSP facilitates collaboration among these stakeholders. The
National Dam Safety Program Act, as amended (33 U.S.C. §§467 et seq.), authorizes the NDSP at $13.4 million annually
through FY2023. The federal government is directly responsible for maintaining the safety of federally owned dams. The
U.S. Army Corps of Engineers and the Bureau of Reclamation own 42% of federal dams, including many large dams. The
remaining federal dams are owned by the Forest Service, Bureau of Land Management, Fish and Wildlife Service,
Department of Defense, Bureau of Indian Affairs, Tennessee Valley Authority, Department of Energy, International
Boundary and Water Commission, and the U.S. Department of Agriculture. Congress has provided various authorities for
these agencies to conduct dam safety activities, rehabilitation, and repair. Congress also has enacted legislation authorizing
the federal government to regulate or rehabilitate and repair certain nonfederal dams. Other federal agencies regulate dams
associated with hydropower projects, mining activities, and nuclear facilities and materials. Selected nonfederal dams may be
eligible for rehabilitation and repair assistance from certain agency programs which are described further in the CRS Report
R47383, Federal Assistance for Nonfederal Dam Safety.
Congress may consider oversight and legislation relating to dam safety in the larger framework of infrastructure
improvements and risk management, or as an exclusive area of interest. Some of these issues are related to many of the
nation’s dams and the federal agencies involved in their dam safety activities, while others are focused on specific dams or
specific federal agencies. Selected issues include the following:
 Federal agency effectiveness in addressing dam safety for federal and nonfederal dams, including implementing
appropriations (e.g., recent influx of funding from the Infrastructure Investment and Jobs Act [P.L. 117-58]) and
determining the sufficient amount of future appropriations to provide for dam safety activities
 Whether, and if so how, to incentivize and support federal and nonfederal agencies and dam owners to
incorporate risk (e.g., risk-informed decisionmaking) in their dam safety practices and how effective these agency
practices are at addressing the risk for communities surrounding and downstream of dams
 Oversight of the National Oceanic and Atmospheric Administration’s mandate to update probable maximum
precipitation study methods to incorporate future climate conditions and of how federal and state agencies may use
these methods to inform dam regulations and design
 Tradeoffs between disclosing dam risk information for public awareness versus preventing individuals or
groups seeking to compromise dams and their operating infrastructure for malicious purposes, including through
cybersecurity attacks, from gaining this knowledge, and how to reduce the vulnerability of dams and their operating
infrastructure from such potential attacks that could compromise dam safety.
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Table 5.Selected IIJA Funding for Dam Safety Activities ............................................................. 32

Contacts
Author Information ........................................................................................................................ 40

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Dam Safety Overview and the Federal Role

Introduction
Dams may be used to provide flood control, navigation, drinking water, hydroelectric power,
irrigation, recreation, fish and wildlife management, and/or waste management benefits.
Construction of dams often causes environmental change (e.g., alteration of riverine habitat).
Owning a dam also may require financial expenditures for operation and maintenance,
rehabilitation (i.e., bringing a dam up to current safety standards), and repair. Federal agencies
reported owning 3% of the more than 91,000 dams in the National Inventory of Dams (NID),
including some of the country’s largest dams (e.g., the Bureau of Reclamation’s Hoover Dam in
Nevada is 730 feet tall with storage capacity of over 30 million acre-feet of water).1 Most dams in
the United States are owned by private entities, state or local governments, or public utilities.
Dam failure and incidents—episodes that, without intervention, likely would have resulted in dam
failure—may threaten public safety, local and regional economies, and the environment; they also
may result in the loss of services provided by a dam.2 Dams can deteriorate as they age, which
may increase the risk of failures and incidents and thereby may increase the potential safety
threat.3 Lack of maintenance and misoperation may amplify dam deterioration. Development in
areas surrounding dams and their reservoirs may amplify the risks associated with dam
deterioration. Security threats, such as cybersecurity attacks that could alter dam operations, are
also a concern for dam safety. Seismic events, floods, and wildfire and associated debris flows
also may impact dams. In recent years, several dam safety incidents have highlighted the public
safety risks posed by the failure of dams and related facilities.
Congress has expressed an interest in dam safety over several decades, often prompted by
destructive events. Dam failures in the 1970s that resulted in the loss of life and billions of dollars
in property damage prompted Congress and the executive branch to establish the NID, the
National Dam Safety Program (NDSP), and other federal activities related to dam safety.4
Following terrorist attacks on September 11, 2001, the federal government focused on dam
security and the potential for acts of terrorism at major dam sites.5 As dams age and the
population density near many dams increases, attention has turned to mitigating the risk of dam

1 Federal agencies self-report dam ownership to the National Inventory of Dams (NID). NID data in this report were
assessed on January 24, 2023, with data last updated on January 18, 2023. Federal agencies reported owning 2,825
dams with some dams owned by multiple federal agencies. One acre-foot of water is the amount of water that will
cover an acre of land to a depth of one foot, or approximately 326,000 gallons.
2 Dam incidents may include overtopping, spillway malfunction or failure, and piping (i.e., internal erosion caused by
seepage), among others. Federal Emergency Management Agency (FEMA), The National Dam Safety Program,
Biennial Report to the United States Congress, Fiscal Years 2018-2019, FEMA P-2189, November 2022, at
https://www.fema.gov/sites/default/files/documents/fema_ndsp-report-congress-fy18-fy19.pdf.
3 Many dams are built for an intended operational lifespan of 50 years. Dams may continue to operate for their purpose
after the 50-year period and may benefit from rehabilitation to expand their operational lifespan and address current
safety standards.
4 Failure of a private mine tailings dam at Buffalo Creek, WV, in 1972, flooded a 16-mile valley and killed 125 people;
Bureau of Reclamation’s Teton Dam, ID, failed in 1976, killing 11 people and causing $1 billion in property damage;
and the private Kelley Barnes Dam, GA, failed in 1977, killing 39 people and causing $2.8 million in damage. FEMA,
The National Dam Safety Program, Biennial Report to the United States Congress, Fiscal Years 2016-2017, May 2019,
at https://www.fema.gov/sites/default/files/2020-08/national-dam-safety_biennial-report-2016-2017.pdf. Hereinafter
FEMA, National Dam Safety Program, 2016-2017.
5 FEMA, Dam Safety and Security in the United States: A Progress Report on the National Dam Safety Program in
Fiscal Years 2002 and 2003, December 2003, at https://www.fema.gov/sites/default/files/2020-08/2002-2003-progress-
report_dam-safety.pdf.
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failure through dam inspection programs, rehabilitation, and repair, in addition to preventing and
preparing for emergencies.6
This report provides an overview of dam safety and associated activities in the United States,
highlighting the federal role in dam safety. The primary federal agencies involved in these
activities include the Federal Emergency Management Agency (FEMA), the U.S. Army Corps of
Engineers (USACE), the Bureau of Reclamation (Reclamation), and the Federal Energy
Regulatory Commission (FERC). The report also discusses potential issues for Congress, such as
the federal role in and funding for dam safety activities; adoption of risk-informed
decisionmaking for dam safety; and awareness of dam safety risks and security issues. The report
does not discuss in detail emergency response to a dam incident, dam building and removal
policies, or state dam safety programs.
Safety of Dams in the United States
Dam safety generally focuses on preventing dam failure and incidents. Challenges to maintaining
dam safety include aging and inadequately constructed dams, frequent or severe floods (for
instance, due to climate change), misoperation of dams, and dam security.7 The risks associated
with dam misoperation and failure also may increase as populations and development encroach
on the areas upstream and downstream of some dams.8 Safe operation and proper maintenance of
dams and associated structures is fundamental for dam safety. In addition, routine inspections by
dam owners and regulators determine a dam’s hazard potential (see “Hazard Potential,” below)
and possible needs for rehabilitation and repair.9
Dams by the Numbers
USACE maintains the NID, a database of dams in the United States.10 For a dam to be included in
the NID, it must be an artificial barrier that has the ability to impound water, wastewater, or any
liquid-borne material for the purpose of storage or control of water that (1) is at least 25 feet in
height with a storage capacity of more than 15 acre-feet, (2) is greater than 6 feet in height with a
storage capacity of at least 50 acre-feet, or (3) poses a significant threat to human life or property
should it fail (i.e., high or significant hazard dams).11 Thousands of dams do not meet these
criteria; therefore, they are not included in the NID.

6 FEMA, National Dam Safety Program, 2016-2017; National Research Council (NRC), Dam and Levee Safety and
Community Resilience: A Vision for Future Practice, 2012, at https://doi.org/10.17226/13393. Hereinafter National
Research Council, Dam and Levee Safety.
7 Michelle Ho et al., “The Future Role of Dams in the United States of America,” Water Resources Research, vol. 53,
no. 2 (2017), at https://doi.org/10.1002/2016WR019905.
8 FEMA, Risk Exposure and Residual Risk Related to Dams, 2017, at https://www.fema.gov/sites/default/files/2020-08/
ta2-risk_exposure_residual_risk_related_dams.pdf. Hereinafter FEMA, Risk Exposure.
9 Hazard potential reflects the amount and type of damage that a failure would cause. FEMA, Federal Guidelines for
Dam Safety Risk Management, FEMA P-1025, 2015, at https://www.fema.gov/sites/default/files/2020-08/fema_dam-
safety_risk-management_P-1025.pdf.
10 Online NID data are used throughout this report unless otherwise specified. State and federal agencies self-report
dam information to the NID. In this report, the number of dams owned by federal agencies are based on federal agency
reporting to the NID. State agencies also reported additional dams owned by the federal government, though CRS
could not confirm ownership of these dams. The NID can be accessed at https://nid.sec.usace.army.mil. Hereinafter
NID, assessed on January 24, 2023, with data last updated on January 18, 2023.
11 33 U.S.C. §467.
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National Inventory of Dams
After several dam failures in the early 1970s, Congress authorized the U.S. Army Corps of Engineers (USACE) to
inventory the nation’s dams and tasked it with other dam safety responsibilities in P.L. 92-367 (33 U.S.C. §467d).
Pursuant to the act, USACE first published the National Inventory of Dams (NID) in 1975. The NID now includes
over 91,000 dams. States, territories, and federal agencies report the information contained in the database; these
entities col aborate closely with USACE to improve the accuracy and completeness of information. Starting in
2021, the NID has allowed agencies to update data in real-time instead of only through annual calls for
information. In addition, USACE also now includes flood inundation maps for most USACE dams, which show
possible flooding from dam incidents by modeling a limited set of standard flood scenarios. The NID allows other
agencies to provide inundation maps for their dams. Multiple acts have reauthorized appropriations for the NID;
most recently, the Water Resources Development Act of 2018 (Title I of P.L. 115-270) extended the NID’s annual
authorization of appropriations of $500,000 through FY2023. From FY2014 to FY2022, Congress appropriated
$400,000 annually to maintain the NID; in FY2023, Congress appropriated $500,000 to maintain the NID. The
NID can be accessed at https://nid.sec.usace.army.mil.
The most common type of dam is an earthen dam (see Figure 1), which is made from natural soil,
rock, or mining waste materials. Other dam types include concrete dams, tailings dams (i.e., dams
that store mining byproducts), overflow dams (i.e., dams regulating downstream flow), and dikes
(i.e., dams constructed at a low point of a reservoir of water).12 This report does not cover levees,
which are manmade structures designed to control water movement along a landscape.
Figure 1. Illustration of an Earthen Dam

Source: FEMA, Pocket Safety Guide for Dams and Impoundments, 2016, at https://www.fema.gov/sites/default/files/
2020-08/fema_911_pocket_safety_guide_dams_impoundments_2016.pdf.
Notes: Earthen dams use natural materials, generally with minimum processing, and can be built with primitive
equipment under conditions where any other construction material would be impracticable. Other dam types
(e.g., concrete dams, tailings dams that store byproducts of mining operations) may have alternative design and
structural components.

12 The United States Society on Dams, “Types of Dams,” at https://www.ussdams.org/dam-levee-education/overview/
types-of-dams/.
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The nation’s dams have been constructed for various purposes: recreation, flood control,
ecological management (e.g., fisheries management), irrigation and water supply,
hydroelectricity, mining, navigation, and others (see Figure 2). A dam may serve multiple
purposes. Although some dams were built before 1900s (e.g., ~2,300 of the dams in the NID),
nearly half of dams in the NID were built between 1950 and 1980 (over 43,000 NID dams).13
After this period, construction of new dams slowed (e.g., the NID lists a little over 4,700 dams
built since 2000). Dams are built to the engineering and construction standards and regulations
that apply at the time of their construction. As a result, some dams may not meet current dam
safety standards, which have evolved over time as scientific data and engineering have
improved.14 These dams may not operate properly or may even fail from certain flooding and
seismic events that are now known to be possible at the site based on improved understanding of
weather and flood data, such as probable maximum flood, and seismic data.
Figure 2. National Dam Statistics

Source: Congressional Research Service (CRS) with National Inventory of Dams (NID) data accessed at
https://nid.sec.usace.army.mil on January 24, 2023, with data last updated on January 18, 2023.
Notes: Some dams have multiple purposes. The “Ecological Purposes” category includes dams used for various
fish and wildlife ponds or fire protection, and the “Other” category may include dams used for debris control
and grade stabilization. A total of 17,577 dams in the NID had no age of construction reported.

13 NID, accessed on January 24, 2023, with data last updated on January 18, 2023. 17,577 dams in the NID had no age
of construction reported.
14 American Society of Civil Engineers, Infrastructure Report Card: Dams, 2021, at
https://www.infrastructurereportcard.org/dams/; hereinafter ASCE, Infrastructure Report Card.
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Dam Failures and Incidents
Dam failures and incidents may occur for various reasons. Potential causes include floods that
may exceed design capacity; faulty design or construction; misoperation or inadequate operation
plans; overtopping, with water spilling over the top of the dam; foundation defects, including
settlement and slope instability; cracking caused by movements, including seismic activity;
inadequate maintenance and upkeep; and piping, when seepage through a dam forms holes in the
dam (see Figure 3).15
Figure 3. Selected Potential Failure Modes of Dams

Source: FEMA, Pocket Safety Guide for Dams and Impoundments, 2016, at https://www.fema.gov/sites/default/files/
2020-08/fema_911_pocket_safety_guide_dams_impoundments_2016.pdf.
Notes: The figure is of an earthen dam; other dams may have different potential modes of failure. Some
potential failure modes are not il ustrated, such as spil way damage and sinkholes.
Engineers and organizations have documented dam failure in an ad hoc manner for decades.16
Some report over 1,600 dam failures resulting in approximately 3,500 casualties in the United
States since the middle of the 19th century, although these numbers are difficult to confirm.17
Between 2000 and 2020, states reported 270 failures and 581 non-failure dam safety incidents.18
A number of more recent dam incident and failure events have led to increased attention on the
condition of dams and the federal role in dam safety. Many failures are of spillways and small
dams, which may result in limited flooding and downstream impact compared to large dam
failures. Flooding that occurs when a dam is breached may not result in life safety consequences

15 National Research Council, Dam and Levee Safety.
16 Personal correspondence between CRS and ASDSO, June 13, 2019. National Research Council, Dam and Levee
Safety.
17 National Research Council, Dam and Levee Safety; personal correspondence between CRS and ASDSO, June 13,
2019. Although these sources provide information on dam failures and casualties, this information is self-reported.
18 A nonfailure incident is an incident at a dam that will not, by itself, lead to a failure but that requires investigation
and notification of internal and/or external personnel. The failure and nonfailure incident estimate may be uncertain.
Because reporting is voluntary, few private or local dams are included. Nonfailure events also may represent a
drowning or injury not directly arising from a dam with structural deficiencies. ASDSO, “Roadmap to Reducing Dam
Safety Risks,” at https://www.damsafety.org/Roadmap.
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or significant property damage.19 Still, some dam failures have resulted in notable disasters in the
United States.20 Some notable dam failures and incidents since 2000 include the following:
 In May 2020, following several days of heavy rain, two dams failed in Michigan,
resulting in widespread flooding and the evacuation of approximately 10,000
downstream residents.21
 In March 2019, the latest dam failure fatality occurred when a hydropower dam
in Nebraska failed because of an icy flood. There was no formal emergency
action plan, because the dam was not classified as a high hazard potential dam.22.
High hazard potential means the loss of at least one life is probable from a dam
failure.
 In 2017, the near failure of Oroville Dam’s spillway in California resulted in a
precautionary evacuation of approximately 200,000 people and more than
$1.1 billion in emergency response and repair.23
 From 2015 to 2018, over 100 dams breached in North Carolina and South
Carolina due to record flooding.24
 Floods resulting from hurricanes in 2017 filled reservoirs of dams to record
levels in some regions—for example, USACE’s Addicks and Barker Dams in the
Houston, TX, area; the Puerto Rico Electric Power Authority’s Guajataca Dam in
Puerto Rico; and USACE’s Herbert Hoover Dike in Florida.25
 The March 2006 failure of the private Ka Loko Dam in Hawaii killed seven
people.26
 The 2003 failure of the Upper Peninsula Power Company’s Silver Lake Dam in
Michigan caused more than $100 million in damage.27

19 National Research Council, Dam and Levee Safety. Gregory B. Baecher et al., Review and Evaluation of the National
Dam Safety Program, University of Maryland, 2011, at https://www.fema.gov/media-library-data/20130726-1830-
25045-3217/damsafetyreport.pdf. Hereinafter Baecher et al., Review and Evaluation, University of Maryland.
20 Baecher et al., Review and Evaluation, University of Maryland; Stanford University, Dam Failures in the U.S., 2018,
at http://npdp.stanford.edu/sites/default/files/reports/npdp_dam_failure_summary_compilation_v1_2018.pdf.
21 On May 19, 2020, following several days of heavy rain, the Edenville Dam on the Tittabawasee River in Gladwin
County, MI, failed and sent a large volume of water downstream; this water overtopped the Sanford Dam in Midland
County, MI. U.S. Geological Survey, “Dam Breaks in Michigan,” at https://www.usgs.gov/centers/eros/dam-breaks-
michigan.
22 ASDSO, Spencer Dam Failure Investigation Report, April 2020, at https://damsafety.org/SpencerDamReport.
23 Spillways are structures to release water from a dam, either as part of regular operations or as part of emergency
operations to reduce water volume or water pressure on the dam and mitigate the risk of failure. ASDSO, Lessons
Learned, “Case Study: Oroville Dam (California, 2017),” at https://damfailures.org/case-study/oroville-dam-california-
2017/.
24 Federal Emergency Management Agency (FEMA), The National Dam Safety Program: Biennial Report to the
United States Congress, Fiscal Years 2016-2017, May 2019, at https://www.fema.gov/sites/default/files/2020-08/
national-dam-safety_biennial-report-2016-2017.pdf. Hereinafter FEMA, National Dam Safety Program, 2016-2017.
25 FEMA, National Dam Safety Program, 2016-2017.
26 Kristina Costa and Donna Cooper, “The 10 States Most Threatened by High-Hazard, Deficient Dams,” Center for
American Progress, 2012, at https://www.americanprogress.org/issues/economy/news/2012/09/20/38679/the-10-states-
most-threatened-by-high-hazard-deficient-dams/.
27 Ibid.
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Oroville Dam, CA
In February 2017, failure of key components of the Orovil e Dam, part of a state-owned hydropower project in
California licensed by the Federal Energy Regulatory Commission (FERC), highlighted the risks that may be
associated with hydropower dams and raised questions about FERC’s oversight of dam safety. Fol owing higher-
than-forecasted inflows from precipitation, snowpack, and subsequent runoff, Orovil e Dam operators opened the
dam’s main service spil way gates, which resulted in the spil way crumbling on one side. In addition, overtopping of
the ungated auxiliary spil way (also referred to as the emergency spil way) initiated erosion of the bedrock that
supports the spil way. These deficiencies prompted concerns about possible dam failure, and local emergency
management officials issued an evacuation order for nearly 200,000 residents downstream of the dam. Dam
operators increased water releases from the damaged main service spil way until dam water levels were safe
enough to begin repairs on the spil way structures. Spil way repairs and emergency response cost an estimated
$1.1 bil ion. At the time of the incident, FERC was reviewing the Orovil e Dam project’s relicensing application. In
January 2018, an independent forensic team and a FERC after-action panel raised questions about the
thoroughness of the state’s and FERC’s oversight of the project, among other factors that may have contributed
to the incident (see section on “Regulation of Hydropower Dams”). The incident also prompted a wave of new
state executive and legislative actions in California requiring inspections of 93 spil ways; emergency action plans
and inundation maps for all dams posing a significant threat to human life or property; and public data release of
hazard classifications, condition assessments, and dam incident inundation maps.

Sources: Independent Forensic Team Report, Oroville Dam Spillway Incident, 2018, at https://damsafety.org/
sites/default/files/files/Independent%20Forensic%20Team%20Report%20Final%2001-05-18.pdf; Federal Energy
Regulatory Commission (FERC), FERC After Action Panel Report, November 23, 2018, at
https://damfailures.org/wp-content/uploads/2022/07/IR_FERC_Orovil e.pdf; personal correspondence
between CRS and the California Division of Safety of Dams on June 4, 2019.
Notes: Figure is an overview of the Orovil e Dam facility prior to February 2017.
Hazard Potential
Federal guidelines set out a hazard potential rating to quantify the potential harm associated with
a dam’s failure or misoperation.28 As described in Table 1, the three hazard ratings (low,
significant, and high) do not indicate the likelihood of failure; instead, the ratings reflect the
amount and type of damage that a failure would cause. Figure 4 depicts the number of dams

28 FEMA, Federal Guidelines for Dam Safety: Hazard Potential Classification System for Dams, 2004, at
https://www.fema.gov/media-library-data/20130726-1516-20490-7951/fema-333.pdf.
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listed in the NID that are classified as high hazard in each state; 60% of dams in the NID are
classified as low hazard. From 2000 to 2023, thousands of dams were reclassified, increasing the
number of high hazard dams from 9,921 to 14,934.29 According to FEMA, the primary factor
increasing dams’ hazard potential is hazard creep—development upstream and downstream of a
dam, especially in the dam failure inundation zone (i.e., downstream areas that would be
inundated by water from a possible dam failure), that increases the potential consequences of a
dam failure.30 Reclassification from low hazard potential to high or significant hazard potential
may trigger more stringent requirements by regulatory agencies, such as increased spillway
capacity, structural improvements, more frequent inspections, and creating or updating an
emergency action plan (EAP).31 Some of these requirements may be process and procedure based,
and others may require structural changes for existing facilities.
Table 1. Hazard Potential of Dams in the United States
Number
Percent of
of NID
NID Dams
Hazard Potential
Result of Failure or Misoperation
Dams
High Hazard

Loss of at least one life is probable
14,934
16%

Other economic or environmental loss possible but
not necessary for this classification
Significant Hazard

No probable loss of human life
10,387
11%

Could result in economic loss, environmental
damage, disruption of lifeline facilities, etc.
Low Hazard

No probable loss of human life
54,819
60%

Few economic or environmental losses; losses are
generally limited to the owner
Undetermined

Hazard potential has not been designated or was not 11,545
13%
provided

Sources: FEMA, Federal Guidelines for Dam Safety: Hazard Potential Classification System for Dams, 2004, at
https://www.fema.gov/media-library-data/20130726-1516-20490-7951/fema-333.pdf; and National Inventory of
Dams (NID) data accessed at https://nid.sec.usace.army.mil on January 24, 2023, with data last updated on
January 18, 2023.
Notes: Low hazard dams are not included in the NID if they are less than 25 feet in height with a storage
capacity of 15 acre-feet or less, or are 6 feet or less in height with a storage capacity of less than 50 acre-feet.

29 FEMA, National Dam Safety Program, 2016-2017. NID, accessed on January 24, 2023, with data last updated on
January 18, 2023.
30 FEMA, National Dam Safety Program, 2016-2017; FEMA, Risk Exposure.
31 ASCE, Infrastructure Report Card; U.S. Congress, House Committee on Transportation and Infrastructure,
Subcommittee on Economic Development, Public Buildings, and Emergency Management, Proposed Amendments to
and Reauthorization of the National Dam Program Act, 109th Cong., 2nd sess., July 26, 2006.
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Figure 4. High Hazard Dams in States and Territories

Source: CRS using National Inventory of Dams (NID) data accessed at https://nid.sec.usace.army.mil on January
24, 2023, with data last updated on January 18, 2023. Data for Texas are from 2019 NID data.
Notes: Guam has one high hazard dam. The NID does not list dams from territories other than Guam and
Puerto Rico.
Risk Management
Preventing dam failure involves proper location, design, and construction of structures and
regular technical inspections, O&M, and rehabilitation and repair of existing structures.32
Preparing and responding to dam safety concerns may involve community development planning,
emergency preparation, and stakeholder awareness.33 Dam safety policies may address the risk
that dams pose by focusing on preventing dam failure while preparing for the consequences if
failure occurs.
Federal agencies and state dam safety agencies traditionally applied a deterministic, standards-
based approach to dam safety by mainly considering a dam’s structural integrity to determine
how it would withstand maximum probable floods and maximum credible earthquakes. This
approach resulted in these agencies providing condition assessments—assessments of relative
dam deficiencies determined from inspections. The NID still includes condition assessments as
reported by state agencies (see Table 2) and some federal agencies.34 Of the 13,669 high hazard

32 FEMA, “Dam Operation and Maintenance,” at https://www.fema.gov/dam-operation-and-maintenance.
33 FEMA, Risk Reduction Measures for Dams, 2018, at https://www.fema.gov/sites/default/files/2020-08/fact-
sheet_risk-reduction-measures-dams.pdf. Hereinafter FEMA, Risk Reduction.
34 Condition is an assessment of any potential dam deficiencies determined from inspections. States and federal
agencies may have additional definitions and rating applications that are used to classify dams, which may vary from
state to state as well as among federal agencies. ASCE, Infrastructure Report Card; FEMA, The National Dam Safety
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potential nonfederal dams in the NID as of January 2023, 61% had satisfactory or fair condition
assessment, 15% had a poor or unsatisfactory condition assessment, and 24% were not rated.35
For dams rated as poor and unsatisfactory, state regulatory agencies may take actions to reduce
risk, such as reservoir drawdowns, and may convey updated risk and response procedures to
stakeholders.36
Table 2. Condition Assessment of Nonfederal Dams in the United States
High
Significant
Low
Undetermined
Condition
Hazard
Hazard
Hazard
Hazard
Ratings
Description of Condition Rating
Dams
Dams
Dams
Dams
Satisfactory

No existing or potential dam
4,515
2,428
4,308
334
safety deficiencies are recognized.
Acceptable performance is
expected under all conditions in
accordance with the minimum
applicable regulatory criteria or
tolerable risk guidelines.
Fair

No existing dam safety deficiencies
3,881
2,315
4,234
1,038
are recognized for normal
operating conditions.

Rare or extreme hydrologic
and/or seismic events may result
in a dam safety deficiency.

Risk may be in the range to take
further action.
Poor

A dam safety deficiency is
1,758
1,513
3,367
185
recognized for normal operating
conditions that may realistically
occur.

Remedial action is necessary.

Uncertainties may exist to identify
a potential dam safety deficiency
and investigations and studies are
necessary.
Unsatisfactory

A dam safety deficiency is
251
116
304
98
recognized that requires
immediate or emergency remedial
action for problem resolution.
Not Rated

The dam has not been inspected,
3,265
3,721
41,346
9,884
is not required to be inspected, or
has been inspected but not rated.
Source: National Inventory of Dams (NID) data accessed at https://nid.sec.usace.army.mil on January 24, 2023,
with data last updated on January 18, 2023; and USACE, National Inventory of Dams, Data Dictionary, August 2022,
at https://nid.usace.army.mil/#/documents.
Notes: A dam safety deficiency is an unacceptable dam condition that may affect the safety of the dam either in
the near term or in the future.

Program: Biennial Report to the United States Congress, Fiscal Years 2012-2013, 2014, at https://www.fema.gov/
media-library-data/1467048771223-c5323440700a175565a2c0c9d604f9e3/DamSafetyUnitedStatesAug2014.pdf.
35 NID data accessed on January 24, 2023, with data last updated on January 18, 2023.
36 National Research Council, Dam and Levee Safety.
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Some federal agencies (e.g., Reclamation, USACE, FERC) have since transitioned from this
solely standards-based approach for their dam safety programs to a portfolio-wide risk-informed
decisionmaking (RIDM) management approach to dam safety. These and other federal agencies
working toward adopting a RIDM management approach no longer report condition assessment
to the NID. Instead, some of these agencies use rating systems, such as the ones in Table 3.
According to FEMA, “a risk-management approach seeks to improve the resilience of dam
infrastructure and mitigate failure of dams and related structures through inspection programs,
risk reduction measures, and rehabilitation and repair.”37 In the context of dam safety, risk
comprises three parts:38
 the likelihood of a triggering event (e.g., flood or earthquake),
 the likelihood of a dam safety deficiency resulting in adverse structural response
(e.g., dam failure or spillway damage), and
 the magnitude of potential consequences resulting from the adverse event (e.g.,
loss of life or economic damages).
Evaluating and reducing risk requires a framework that explicitly evaluates the level of risk if no
action is taken, including for all modes of failure (e.g., seepage of water and sediment through a
dam), and recognizes the monetary and nonmonetary costs and benefits of reducing risks when
making decisions. The RIDM framework comprises risk assessment, risk management, and risk
communication. The RIDM assessment process aims to inform better decisionmaking and to
enable more effective use of limited resources. Some state dam safety agencies (e.g., Colorado)
also are working to incorporating a risk management approach.39
Table 3. Summary of Dam Safety Rating Systems for USACE (DSAC) and Bureau of
Reclamation (DSPR)

USACE Dam Safety Action Classification
Reclamation Dam Safety Priority Ratings
Ratings (DSAC)
(DSPR)
1
Very High Urgency—almost certain to fail
Immediate Priority—active failure mode or
immediately to a few years under normal operations
extremely high likelihood of failure requiring
or the combination of consequences and failure
immediate actions to reduce risk.
probability is extremely high.
2
High Urgency—likelihood of failure during normal
Urgent Priority—potential failure modes are
operations or a consequence of an event is too high
judged to present various serious risks, which justify
to assure public safety or the combination of
urgency to reduce risk.
consequences and failure probability is very high.
3
Moderate Urgency—dam may have issues where
Moderate to High Priority—potential failure
the incremental risk is moderate and the level of life-
modes appear to be dam safety deficiencies that
risk is unacceptable except in unusual circumstances.
propose a significant risk of failure, and actions are
needed to better define risks or to reduce risks.
4
Low Urgency—dam is inadequate but with low
Low to Medium Priority—potential failure modes
risk, such that the combination of consequences and
appear to indicate a potential concern but do not
failure probability is low. Dam may not meet all
indicate a pressing need for action.
USACE engineering guidelines.

37 FEMA, The National Dam Safety Program: Biennial Report to the United States Congress, Fiscal Years 2018-2019,
November 2022, at https://www.fema.gov/sites/default/files/documents/fema_ndsp-report-congress-fy18-fy19.pdf.
38 Personal correspondence between CRS and FEMA, June 26, 2019.
39 State of Colorado, Department of Natural Resources, Guidelines for Comprehensive Dam Safety Evaluation (CDSE)
Risk Assessments & Risk Informed Decision Making (RIDM), March 8, 2021, at https://dnrweblink.state.co.us/dwr/
ElectronicFile.aspx?docid=3566811&dbid=0.
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USACE Dam Safety Action Classification
Reclamation Dam Safety Priority Ratings
Ratings (DSAC)
(DSPR)
5
Normal—considered safe, meeting all agency
Low Priority—potential failure modes do not
guidelines, with tolerable residual risk.
appear to present significant risk, and there are no
apparent dam safety deficiencies.
Sources: Bureau of Reclamation, Dam Safety Public Protection Guidelines: A Risk Framework to Support Dam Safety
Decision-Making, 2011, at https://www.usbr.gov/ssle/damsafety/documents/PPG201108.pdf. U.S. Army Corps of
Engineers (USACE), Safety of Dams – Policy and Procedures, Engineering Regulation 1110-2-1156 at
https://www.publications.usace.army.mil/Portals/76/Publications/EngineerRegulations/ER_1110-2-1156.pdf.
Rehabilitation and Repair
Rehabilitation typically consists of bringing a dam up to current safety standards (e.g., increasing
spillway capacity, installing modern gates, addressing major structural deficiencies), and repair
addresses damage to a structure. Rehabilitation and repair are different from day-to-day O&M. In
2022, the Association of State Dam Safety Officials estimated that $75.7 billion was needed to
rehabilitate nonfederal dams; of that amount, $24.0 billion was needed for high hazard potential
nonfederal dams.40 Federal agencies report various funding estimates needed for rehabilitation
and repair of dam that they manage. Some stakeholders project that funding requirements for dam
safety rehabilitation and repair will continue to grow as infrastructure ages, risk awareness
progresses, and design standards evolve.41
Preparedness
Dam safety processes and products—such as EAPs and inundation maps—may support informed
decisionmaking to reduce the risk and consequences of dam failures and incidents.42 An EAP is a
formal document that identifies potential emergency conditions at a dam and specifies preplanned
actions to minimize property damage and loss of life.43 EAPs identify the actions and
responsibilities of different parties in the event of an emergency, such as the procedures for
issuing early warning and notification messages to emergency management authorities. EAPs
also contain inundation maps to show emergency management authorities the critical areas for
action in case of an emergency (see Figure 5 for a map illustration of potential inundation areas
due to a hypothetical dam breach).44 Many agencies that are responsible for dam oversight require
or encourage dam owners to develop EAPs and often oversee emergency response simulations
(i.e., tabletop exercises) and field exercises.45 Requirements for EAPs often focus on high hazard

40 ASDSO, The Cost of Rehabilitating Our Nation’s Dams, March 2022, at https://damsafety-prod.s3.amazonaws.com/
s3fs-public/files/Cost%20of%20Rehab%20Report-2022%20FINAL.pdf.
41 ASCE, Infrastructure Report Card.
42 FEMA, Risk Reduction.
43 FEMA, Federal Guidelines for Dam Safety: Emergency Action Planning for Dams, 2013, at
https://www.swc.nd.gov/pdfs/fema_64_emergency_action_planning_dams.pdf.
44 Inundation area from dam or associated structural failure is typically calculated using computer models. These
include hydrologic runoff and hydraulic flow models as well as models that estimate dam failure breach formation and
discharge hydrographs. The models use parameters such as precipitation, snowmelt (if needed), runoff rates, watershed
slope, downstream channel topography and other characteristics. The models used in most cases are HEC-RAS
(developed by USACE) and DSS-WISE developed by the University of Mississippi for the Department of Homeland
Security.
45 FEMA, National Dam Safety Program, 2016-2017. Tabletop exercises are designed to help test a hypothetical
situation, such as a dam failure, and evaluate responders’ ability to respond and work together.
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dams. In 1999, 35% of state regulated high hazard potential dams had EAPs.46 In January 2023,
the percentage of high hazard potential dams in the United States with EAPs was 82% for state-
regulated dams and 97% for federally owned dams.47
Figure 5. USACE Potential Flood Inundation Map for Isabella Dam

Source: CRS with data from National Inventory of Dams (NID) data accessed at https://nid.sec.usace.army.mil.
Notes: Flood inundation maps il ustrate how far flood water may extend beyond the river channel by overlaying
a shaded zone on a map of the river and its surrounding topography. These maps also show how deep the flood
waters are anticipated to be for various flood scenarios. These projected flood depths are displayed as ranges (in
feet) for specific sections of the potentially flooded areas. In particular, the U.S. Army Corps of Engineers
(USACE) develops a set of flood inundation maps for each of its dams by modeling a limited set of standard
flooding scenarios. The map above is for a hypothetical breach occurring at USACE’s Isabella Dam when water
levels are at the top of the active storage pool. USACE completed dam safety modification construction in 2022;
this scenario is based on modeling from before this construction project. Flood inundation maps are designed to
show the upper limit of potential impacts. Not all the standard flooding scenarios are equally likely to occur, and
the maps are not intended to be predictive of what situations wil occur. Flood inundation maps are available in
the NID for most USACE dams. Currently, most other federal agencies do not publicly release inundation maps
for federally owned dams. Some states, such as California, provide flood inundation map information on their
own websites.
Federal agencies have developed tools to assist dam owners and regulators, along with emergency
managers and communities, to prepare for, monitor, and respond to dam failures and incidents.
 FEMA’s RiskMAP program provides flood maps, tools to assess the risk from
flooding, and planning and outreach support to communities for flood risk
mitigation.48 A RiskMAP project may incorporate the potential risk of dam
failure or incidents.

46 ASDSO, “Roadmap to Reducing Dam Safety Risks,” at https://www.damsafety.org/Roadmap.
47 NID data accessed at https://nid.sec.usace.army.mil on January 24, 2023, with data last updated on January 18, 2023.
48 FEMA, “Risk Mapping, Assessment and Planning (Risk MAP),” at https://www.fema.gov/flood-maps/tools-
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 FEMA’s Decision Support System for Water Infrastructure Security (DSS-
WISE) Lite allows states to conduct dam failure simulations and human
consequence assessments.49 Using DSS-WISE Lite, FEMA conducted emergency
dam-break flood simulation and inundation mapping of 36 dams in Puerto Rico
during the response to Hurricane Maria in 2017.
 DamWatch is a web-based monitoring and informational tool for 11,800
nonfederal flood control dams built with assistance from the U.S. Department of
Agriculture.50 When these dams experience a critical event (e.g., threatening
storm systems), essential personnel are alerted via an electronic medium and can
implement EAPs if necessary.
 The U.S. Geological Survey’s ShakeCast is a post-earthquake awareness
application that notifies responsible parties of dams about the occurrence of a
potentially damaging earthquake and its potential impact at dam locations.51 The
responsible parties may use the information to prioritize response, inspection,
rehabilitation, and repair of potentially affected dams.
Federal Role and Resources for Dam Safety
In addition to owning dams, the federal government is involved in multiple areas of dam safety
through legislative and executive actions. Following USACE’s publication of the NID in 1975 as
authorized by P.L. 92-367, the Interagency Committee on Dam Safety—established by President
Jimmy Carter through Executive Order 12148—released safety guidelines for dams regulated by
federal agencies in 1979.52 In 1996, the National Dam Safety Program Act (Section 215 of the
Water Resources Development Act of 1996, as amended; P.L. 104-303; 33 U.S.C. §§467 et seq.)
established the National Dam Safety Program (NDSP), the nation’s principal dam safety program,
under the direction of FEMA. Congress has reauthorized the NDSP and enacted other dam safety
programs and activities related to federal and nonfederal dams.53 A chronology of selected federal
dam safety actions is provided in the box below.

resources/risk-map.
49 FEMA, DSS-WISETM HCOM: Human Consequences of Dam-Break Floods, at https://www.fema.gov/media-
library-data/1593524739829-955771e7e1eed3a8d6a36a5d1e79abf7/DSS-WISE_HCOM_Fact_Sheet.pdf.
50 U.S. Engineering Solutions, “DamWatch,” at https://www.usengineeringsolutions.com/dam-watch/.
51 U.S. Geological Survey (USGS), “The USGS ShakeCast System,” at https://www.usgs.gov/news/usgs-shakecast-
system.
52 Executive Order 12148, “Federal Emergency Management,” 44 Federal Register 43239, 1979, at
https://www.archives.gov/federal-register/codification/executive-order/12148.html. The federal guidelines for dam
safety established a basic structure for agencies’ dam safety programs. The guidelines have been updated subsequently.
FEMA, Federal Guidelines for Dam Safety, 2004, at https://www.fema.gov/sites/default/files/2020-08/fema_dam-
safety_P-93.pdf. Hereinafter FEMA, Federal Guidelines.
53 Baecher et al., Review and Evaluation, University of Maryland.
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Chronology of Selected Federal Administrative and
Legislative Actions for Dam Safety
1972 An Act to Authorize
Authorized the U.S. Army Corps of Engineers (USACE) to undertake a national
the Secretary of the Army
program of dam inspection, to create the National Inventory of Dams (NID),
to Undertake a National
and to provide recommendations to Congress for dam safety policies.
Program of Inspection of
Inspections were not undertaken due to a lack of appropriations and
Dams (P.L. 92-367)
uncertainty in the federal government’s authority to inspect nonfederal dams.
1975
USACE publishes the first version of the NID.
1977 Memorandum from
Directed federal agencies to review their dam safety practices and established
President Carter
an ad hoc Interagency Committee on Dam Safety (ICODS).

1978
USACE established a National Dam Inspection Program and reported that one-
third of the nonfederal dams inspected in a preliminary “Phase I Inspection
Program” survey were unsafe. Subsequently, more states established or
enhanced dam safety programs.
1978 Reclamation Safety of
Authorized the Bureau of Reclamation (Reclamation) to make dam safety
Dams Act of 1978 (P.L. 95-
modifications at Reclamation dams.
578)
1979 President Carter
Required the newly established Federal Emergency Management Agency
issued Executive Order
(FEMA) to coordinate agency efforts to promote dam safety.
12148
Formally established the ICODS, which also released the first Federal Guidelines
for Dam Safety in 1979.
1984 Reclamation Safety of
Altered funding of Reclamation dam safety modification projects by instituting a
Dams Act Amendments of
nonfederal cost share of 15%.
1984 (P.L. 98-404)
1986 Water Resources
Authorized USACE to distribute grants to state dam safety programs, provide
Development Act of 1986
inspection trainings, update the NID, establish a National Dam Safety Review
(P.L. 99-662)
Board (NDSRB) with seven members, and research dam safety. Only activities
related to the NID were subsequently funded.
Provided cost-share parameters for USACE dam modifications and activities at
USACE-constructed dams.
1987
FEMA published the Model State Dam Safety Program, a guideline for developing

state dam safety programs.
1994 Indian Dams Safety
Directed the Bureau of Indian Affairs (BIA) to classify the condition of dams on
Act of 1994 (P.L. 103-302)
Indian lands, establish a dam safety maintenance and repair program, and
rehabilitate dams in an unsatisfactory condition.
1996 Water Resources
Established the National Dam Safety Program (NDSP) under FEMA by
Development Act of 1996
transferring many dam safety activity authorities from USACE. Reauthorized
(P.L. 104-303)
grants to state dam safety programs and research at reduced funding levels and
training at the same funding level. Established the NDSRB under FEMA with 11
members. Authorized USACE to continue NID updates.
2000 Grain Standards and
Established a Small Watershed Rehabilitation Program to provide technical and
Warehouse Improvement
financial assistance for design and rehabilitation of aging dams constructed
Act of 2000 (P.L. 106-472)
under certain U.S. Department of Agriculture programs.
2002 Dam Safety and
Reauthorized the NDSP, added national security considerations to the legal
Security Act of 2002 (P.L.
framework, and increased authorization of appropriations for grants to state
107-310)
dam safety programs and research.
2006 Dam Safety Act of
Reauthorized the NDSP with increased authorization of appropriations and
2006 (P.L. 109-460)
added condition assessment ratings to the NID.
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2014 Water Resources
Reauthorized the NDSP and increased the authorization of appropriations
Reform and Development
amounts (including the NID). Directed FEMA to implement a dam safety public
Act of 2014 (P.L. 113-121)
awareness initiative and to add nongovernment organizations to the NDSRB.
2016 Water Infrastructure
Authorized FEMA to provide grants for design and construction assistance to
Improvements for the
nonfederal sponsors for rehabilitation, repair, or removal of eligible high hazard
Nation Act (P.L. 114-322)
dams (i.e., Rehabilitation of High Hazard Potential Dam Grant Program).
Established Indian Dam Safety Deferred Maintenance Funds to address deferred
maintenance, repair, and replacement needs of Indian high hazard and low
hazard dams. Established a Tribal Safety of Dams Committee.
2018 America’s Water
Reauthorized appropriations for the NDSP through FY2023 and provisions of
Infrastructure Act of 2018
Section 3101 (Indian Dam Safety) of P.L. 114-322 through FY2030.
(P.L. 115-270)
Directed the Federal Energy Regulatory Commission (FERC) to assess
nonfederal dam structures before expediting hydropower development
licensing at nonpowered dams and closed-loop pumped storage projects.
2020 Consolidated
Amended the authorization for FEMA’s Rehabilitation of High Hazard Potential
Appropriations Act, 2021
Dam Grant Program.
(P.L. 116-260)
Created a new USACE account, Water Infrastructure Finance and Innovation
Program Account, and through the account provided first funds for the Corps
Water Infrastructure Financing Program (as authorized by 33 U.S.C. §§3901-
3914) to provide credit assistance for nonfederal dam safety projects.
2021 Infrastructure
Provided authority and/or appropriations for various activities directly or
Investment and Jobs Act
indirectly related to dam safety activities, such as $148 mil ion for NDSP state
(P.L. 117-58)
program grant assistance, $585 mil ion for the Rehabilitation of High Hazard
Potential Dam Grant Program, and $67 mil ion for other NDSP activities.
2022 James M. Inhofe
Amended the National Dam Safety Program Act to direct USACE to develop a
National Defense
national low-head dam inventory and authorized $30 mil ion to do so.
Authorization Act for Fiscal
Year 2023
(P.L. 117-347)
Source: CRS using selected public laws and executive orders; FEMA, The National Dam Safety Program: Biennial
Report to the United States Congress, Fiscal Years 2016-2017, May 2019, at https://www.fema.gov/sites/default/files/
2020-08/national-dam-safety_biennial-report-2016-2017.pdf; and the National Research Council (NRC), Dam
and Levee Safety and Community Resilience: A Vision for Future Practice, 2012, at https://doi.org/10.17226/13393.

National Dam Safety Program
The NDSP is a federal program established to facilitate collaboration among the various federal
agencies, states, and owners with responsibility for dam safety.54 The NDSP also provides dam
safety information resources and training, conducts research and outreach, and supports state dam
safety programs with grant assistance. The NDSP does not mandate uniform standards across dam
safety programs.

54 The stated purpose of the NDSP was “to reduce the risks to life and property from dam failure in the United States
through the establishment and maintenance of an effective national dam safety program to bring together the expertise
and resources of the Federal and non-Federal communities in achieving national dam safety hazard reduction.” FEMA,
National Dam Safety Program, 2016-2017. National Research Council, Dam and Levee Safety. For information on the
National Dam Safety Program (NDSP), see FEMA, “National Dam Safety Program,” at https://www.fema.gov/
national-dam-safety-program.
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Advisory Bodies of the National Dam Safety Program
The National Dam Safety Review Board (NDSRB) advises FEMA’s director on dam safety
issues, including the allocation of grants to state dam safety programs. The board is to consist of
five representatives appointed from federal agencies, five state dam safety officials, and one
representative from the private sector.55 The Interagency Committee on Dam Safety (ICODS)
serves as a forum for coordination of federal efforts to promote dam safety. ICODS is chaired by
FEMA and is to include representatives from FERC, the International Boundary and Water
Commission, the Nuclear Regulatory Commission (NRC), the Tennessee Valley Authority, and
the Departments of Agriculture, Defense, Energy, the Interior (DOI), and Labor (DOL).56
Assistance to State Dam Safety Programs
Every state (except Alabama) has established a regulatory program for dam safety, as has Puerto
Rico.57 Collectively, these programs have regulatory authority for 71% of the NID dams.58 State
dam safety programs typically include safety evaluations of existing dams, review of plans and
specifications for dam construction and major repair work, periodic inspections of dams and
construction work on new and existing dams, reviews and approval of EAPs required for certain
dams,59 and engagement with local officials and dam owners on emergency preparedness
activities.60 Funding levels and narrow state statutory authorities may limit the activities of some
state dam safety programs.61 In 2021, 15 states had more than seven full-time employees in their
dam safety program.62 In addition, some states—Alabama, Florida, Indiana, Kentucky, Vermont,
and Wyoming—have not provided regulatory bodies with the authority to require dam owners of
high hazard potential dams to develop EAPs.63 However, state budgets, and accordingly staffing

55 33 U.S.C. §467f(f). For more information, see FEMA, “Advisory Committees,” at https://www.fema.gov/
emergency-managers/risk-management/dam-safety/advisory-committees#review-board.
56 33 U.S.C. §467e.
57 FEMA, National Dam Safety Program, 2016-2017.
58 NID data accessed at https://nid.sec.usace.army.mil on January 24, 2023, with data last updated on January 18, 2023.
States define their own regulatory jurisdiction (the height, volume, and type of dams to be regulated). According to
ASDSO, most states follow the NID criteria, but regulatory statutes vary among states. Some states exempt categories
of dams from inspection based on the purpose of the impoundment or the owner type. For example, Delaware law
exempts dams owned by private individuals and entities; Missouri law exempts all agricultural purpose dams and dams
less than 35 feet in height regardless of storage volume and potential hazard; and Texas law exempts privately owned
significant hazard and low hazard potential dams storing less than a maximum of 500 acre-feet in counties with
population less than 350,000, excluding dams within municipal corporate limits. Personal correspondence between
CRS and ASDSO on August 30, 2019.
59 An emergency action plan (EAP) is a formal document that identifies potential emergency conditions at a dam and
specifies preplanned actions to minimize property damage and loss of life. EAPs identify the actions and
responsibilities of different parties in the event of an emergency, such as the procedures to issue early warning and
notification messages to emergency management authorities. EAPs also contain inundation maps to show emergency
management authorities the critical areas for action in case of an emergency.
60 FEMA, Model State Dam Safety Program, 2022, at https://damsafety-prod.s3.amazonaws.com/s3fs-public/files/
FEMA%20316_Model%20State%20Dam%20Safety%20Program_2022.pdf; FEMA, National Dam Safety Program,
2016-2017.
61 ASDSO, “State Performance and Current Issues,” at https://damsafety.org/state-performance.
62 Past recommendations were for one full-time employee for every 20 state-regulated dams. Updated draft guidance to
states may provide broader recommendations for staffing needs based on the different types of programs, such as state
agencies that perform most dam safety work in-house compared with states that outsource work or require dam owners
to hire engineers to perform inspections. Personal correspondence between CRS and ASDSO on October 17, 2022.
63 Regulations for high hazard potential dams vary by state, although FEMA has encouraged requiring EAPs for high
hazard potential dams. Personal correspondence between CRS and ASDSO on October 17, 2022. ASDSO, Summary of
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levels, have increased over the past couple decades (e.g., 317 full-time employees in 1999
compared with nearly 455 full-time employees in 2022).64
The National Dam Safety Program Act authorizes state assistance programs under the NDSP. This
assistance includes (1) grant assistance to state dam safety programs that are working toward or
meeting minimal requirements as established by the National Dam Safety Program Act,65 (2)
grants for rehabilitation of high hazard potential dams, and (3) trainings for state inspectors,
among other assistance. For more information on NDSP assistance for states, see CRS Report
R47383, Federal Assistance for Nonfederal Dam Safety.
Association of State Dam Safety
National Dam Safety Program
Officials
Reporting
The Association of State Dam Safety Officials (ASDSO)
comprises 3,000 state, federal, and local dam safety
At the end of each odd-numbered fiscal year,
professionals and private sector experts organized to
FEMA is to submit to Congress a report
improve dam safety through research, education, and
describing the NDSP’s status, federal
communication. After its establishment in 1983,
agencies’ progress at implementing the
ASDSO worked with the Federal Emergency
Federal Guidelines for Dam Safety, progress
Management Agency (FEMA) to publish the Model State
Dam Safety Program to assist state officials in initiating
achieved in dam safety by states participating
or improving their state programs. The model outlines
in the program, and any recommendations for
the key components of a dam safety program and
legislation or other actions (33 U.S.C.
provides guidance on the development of state
§467h).66 Federal agencies and states provide
programs, including legislative authorities, to minimize
FEMA with annual program performance
risks created by unsafe dams. ASDSO continues to
support various elements of the National Dam Safety
assessments on key metrics such as
Program, especial y through training initiatives and
inspections, rehabilitation and repair activities,
outreach to dam owners. The Model Dam Safety
EAPs, staffing, and budgets. USACE provides
Program was most recently updated in 2022. The
summaries and analysis of NID data (e.g.,
Model State Dam Safety Program may be accessed at
https://damsafety-prod.s3.amazonaws.com/s3fs-public/
inspections and EAPs) to FEMA. FEMA
files/
published The National Dam Safety Program
FEMA%20316_Model%20State%20Dam%20Safety%20Pr
Biennial Report to the United States Congress,
ogram_2022.pdf. For more information on ASDSO, see
Fiscal Years 2018–2019 on November 17,
https://damsafety.org/.
2022.67 As of March 2023, FEMA had not
published a biennial report covering subsequent years.
Federally Owned Dams
Federally owned dams are dams owned by the federal government that are managed by one or
more federal agencies. The federal government is responsible for maintaining dam safety of
federally owned dams by performing maintenance, inspections, rehabilitation, and repair work.

State Laws and Regulations on Dam Safety, May 2022, at https://damsafety-prod.s3.amazonaws.com/s3fs-public/files/
FINAL%20-%202020%20Update%20State%20Laws%20and%20Regulations%20Summary_0.pdf.
64 ASDSO, “Roadmap to Reducing Dam Safety Risks,” at https://www.damsafety.org/Roadmap.
65 The National Dam Safety Program Act, as amended, (Section 215 of the Water Resources Development Act of 1996;
P.L. 104-303) established 10 criteria that state dam safety programs must meet or be working toward meeting to be
eligible for the grant assistance program (33 U.S.C. § 467f).
66 FEMA, National Dam Safety Program, 2016-2017.
67 FEMA, “Dam Safety in the United States: A Progress Report on the National Dam Safety Program,” at
https://www.fema.gov/emergency-managers/risk-management/dam-safety/progress-report.
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No single agency regulates all federally owned dams; rather, each federal dam is regulated
according to the policies and guidance of the individual federal agency that owns the dam.68 The
Federal Guidelines for Dam Safety provides basic guidance for federal agencies’ dam safety
programs.69
According to the NID, in January 2023, federal agencies reported managing 2,825 federal dams,
with some dams managed by multiple federal agencies (Figure 6).70 Federally owned dams may
be under the jurisdiction of three broad categories of federal agencies:
 Agencies that primarily manage water resources—USACE and Reclamation—
manage 42% of federal dams in the NID, including many large dams. Dams
managed by these agencies may be located on lands managed by other agencies.
 Agencies that manage most federal lands, collectively known as the federal land
management agencies (i.e., the Bureau of Land Management, U.S. Fish and
Wildlife Service, Forest Service [FS], and National Park Service), manage 39%
of federal dams in the NID, which are typically smaller dams.
 Agencies that manage the remainder of federal dams, such as the Department of
Defense and the Tennessee Valley Authority.

68 FEMA, National Dam Safety Program, 2016-2017.
69 FEMA, Federal Guidelines. At times, some agencies have received criticism of their dam safety programs in
carrying out the Federal Guidelines for Dam Safety. For example, in 2014, the Department of Defense (DOD)
Inspector General found that DOD did not have a policy requiring installations to implement a dam safety inspection
program consistent with the Federal Guidelines for Dam Safety. Office of the Inspector General, U.S. Department of
Defense, DOD Needs Dam Safety Inspection Policy to Enable the Services to Detect Conditions that Could Lead to
Dam Failure, U.S. Department of Defense, 2014, at https://media.defense.gov/2019/Aug/22/2002174057/-1/-1/1/
DODIG-2015-062.PDF. Hereinafter Inspector General, DOD Needs Dam Safety Inspection Policy.
70 Federal agencies self-report dam management to the NID. Other federal agency documents may list more dams
managed by their agencies that are not included in the NID. For this report, dam management data are from the NID
unless otherwise noted. NID data accessed at https://nid.sec.usace.army.mil on January 24, 2023, with data last updated
on January 18, 2023.
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Figure 6. Location of Federal Dams and Number of Dams Owned per Agency

Source: CRS using National Inventory of Dams (NID) data accessed at https://nid.sec.usace.army.mil on January
24, 2023, with data last updated on January 18, 2023.
Notes: No federal dams are in Puerto Rico, and one is in Guam. In addition to the agencies shown in the figure,
the U.S. Department of Agriculture’s Agricultural Research Service owns one high hazard dam. Multiple federal
agencies may own a dam. USACE = U.S. Army Corps of Engineers, FS = Forest Service, BOR = Bureau of
Reclamation, FWS = U.S. Fish and Wildlife Service, BLM = Bureau of Land Management, DOD = Department of
Defense, BIA = Bureau of Indian Affairs, TVA = Tennessee Valley Authority, NPS = National Park Service, DOE
= Department of Energy, IBWC = International Boundary and Water Commission.
The Federal Guidelines for Dam Safety recommend that agencies formally inspect each dam that
they own at least once every five years; however, some agencies require more frequent
inspections and base the frequency of inspections on the dam’s hazard potential or their risk-
management approach.71 Inspections may result in an update of the dam’s hazard potential,
among other categorical amendments. After identifying dam safety deficiencies, federal agencies
may undertake risk reduction measures (e.g., nonstructural operation changes) or rehabilitation
and repair activities. Agencies may not have funding available to immediately undertake all
nonurgent rehabilitation and repair; rather, they generally prioritize their rehabilitation and repair
investments based on various forms of assessment and schedule these activities in conjunction
with the budget process.72 At some agencies, dam rehabilitation and repair needs must compete

71 FEMA, Federal Guidelines; National Research Council, Dam and Levee Safety.
72 FEMA, National Dam Safety Program, 2016-2017; Michelle Ho et al., “The Future Role of Dams in the United
States of America,” Water Resources Research, 2017, vol. 53, pp. 982-998.
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for funding with other construction projects (e.g., buildings and levees).73 The following sections
briefly discuss dam safety activities at the three agencies managing the most federal dams.
U.S. Army Corps of Engineers
USACE implements a dam safety program consisting of inspections and risk analyses for
USACE-operated dams, and performs risk reduction measures or project modifications to address
dam safety risks.74 USACE uses a risk-informed approach for all dam safety program decisions
and applies the Dam Safety Action Classification System (DSAC), which is based on the
likelihood of failure in combination with loss of life, economic, or environmental consequences
(see Table 3).75
Congress provides funding for USACE’s various dam safety activities through the Investigations,
O&M, and Construction accounts.76 The Inventory of Dams line item in the Investigations
account provides funding for the maintenance and publication of the NID. The O&M account
provides funding for routine O&M of USACE dams and for NDSP activities, including
assessments of USACE dams.
The Construction account provides funding for nonroutine dam safety activities (e.g., dam safety
rehabilitation and repair modifications).77 The Dam Safety and Seepage/Stability Correction
Program conducts nonroutine dam safety evaluations and studies of extremely high-risk or very
high-risk dams (DSAC 1 and DSAC 2).78 Under the program, an issue evaluation study may
evaluate high-risk dams, dam safety incidents, and unsatisfactory performance, and then provide
determinations for modification or reclassification. If recommended, a dam safety modification
study would further investigate dam deficiencies and propose alternatives to reduce risks to
tolerable levels; a dam safety modification report is issued if USACE recommends a
modification.79 USACE funds construction of dam safety modifications through project-specific

73 FEMA, National Dam Safety Program, 2016-2017.
74 The dam safety program is managed from headquarters, with the dam safety officer responsible for making all dam
safety decisions and ensuring consistent prioritization decisions. USACE districts are responsible for executing the dam
safety program, with oversight from their Dam Safety Production Centers (DSPCs). DSPCs are responsible for
reviewing products and ensuring that all dam safety products meet policy requirements for the program. The Risk
Management Center, which is available as a resource to all districts, provides expertise in dam safety disciplines and
reviews dam safety products from a portfolio perspective. Personal correspondence between CRS and USACE, July 15,
2019. USACE prescribes flood and navigation operations for certain nonfederal dams under the authority of Section 7
of the Flood Control Act of 1944. However, USACE policy states that the nonfederal project owner of these dams “is
responsible for the safety of the dam and appurtenant facilities and for regulation/operation of the project during
surcharge storage…which results when the total storage space reserved for flood control is exceeded.” USACE, Water
Control Manual, Chapter 4, 1110-2-240, May 30, 2016, at https://www.publications.usace.army.mil/portals/76/
publications/engineerregulations/er_1110-2-240.pdf.
75 Incremental risk is the risk (e.g., the likelihood and consequences of inundation) to the reservoir area and
downstream floodplain that can be attributed to the presence of the dam should the dam breach, overtop, or undergo
malfunction or misoperation. For more information, see https://www.usace.army.mil/Missions/Civil-Works/Dam-
Safety-Program/Program-Activities/.
76 Personal correspondence between CRS and USACE, July 15, 2019.
77 Personal correspondence between CRS and USACE, July 15, 2019.
78 Sometimes USACE also evaluates Dam Safety Action Classification (DSAC) 3 dams under the Seepage/Stability
Correction Program. Personal correspondence between CRS and USACE, July 15, 2019.
79 Interim risk-reduction measures for dam safety are developed, prepared, and implemented to reduce the probability
and consequences of failure to the maximum extent that it is reasonably practicable while long-term remedial measures
are pursued. USACE, Engineering and Design, Water Control Management, ER-1110-2-240, 2016, at
https://www.publications.usace.army.mil/Portals/76/Publications/EngineerRegulations/ER_1110-2-240.pdf.
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line items in the Construction account. Modification of USACE-constructed dams for safety
purposes may be cost shared with nonfederal project sponsors using two cost-sharing authorities:
major rehabilitation and dam safety assurance (see below).80 USACE schedules modifications
under all of these programs based on funding availability.
 Major rehabilitation is for significant, costly, one-time structural rehabilitation or major
replacement work. Major rehabilitation applies to dam safety repairs associated with
typical degradation of dams over time. Nonfederal sponsors are to pay the standard cost
share based on authorized purposes. USACE does not provide support under major
rehabilitation for facilities that were turned over to local project sponsors for O&M after
they were constructed by USACE.
 Dam safety assurance cost sharing may apply to all dams built by USACE, regardless of
the entity performing O&M. Modifications are based on new hydrologic or seismic data
or changes in state-of-the-art design or construction criteria that are deemed necessary for
safety purposes. Application of the authority provided by Section 1203 of the Water
Resources Development Act of 1986 (P.L. 99-662; 33 U.S.C. §467n) reduces a sponsor’s
responsibility to 15% of its agreed nonfederal cost share.81
Bureau of Reclamation
Reclamation’s dam safety program, authorized by Reclamation Safety of Dams Act of 1978, as
amended (P.L. 95-578; 43 U.S.C. §§506 et seq.), provides for inspection of and repairs to
qualifying projects at Reclamation dams. Reclamation conducts dam safety inspections through
the Safety Evaluation of Existing Dams (SEED) program using Dam Safety Priority Ratings
(DSPR; see Table 3).82 Corrective actions, if necessary, are carried out through the Initiate Safety
of Dams Corrective Action (ISCA) program. With ISCA appropriations, Reclamation funds
modifications on priority structures based on an evolving identification of risks and needs.
The Reclamation Safety of Dams Act Amendments of 1984, as amended (P.L. 98-404; 42 U.S.C.
§§506 et seq.) requires a 15% cost share from sponsors for dam safety modifications when
modifications are based on new hydrologic or seismic data or changes in state-of-the-art design or
construction criteria that are deemed necessary for safety purposes. Costs resulting from age and
normal deterioration or lack of maintenance of structures are considered project costs and are
allocated and deemed reimbursable based on the authorized project purposes and existing law. In
2015, P.L. 114-113 amended the Reclamation Safety of Dams Act to increase Reclamation’s
authority, before needing congressional authorization to approve a modification project, from
$1.25 million to $20 million.83 The act also authorized the Secretary of the Interior to develop

80 According to ER 1110-2-1156, projects with a formal agreement that identifies the cost sharing percentages for
major rehabilitation or dam safety modifications must be cost shared with a nonfederal sponsor in accordance with the
agreement (i.e., contract). Projects without a formal agreement will be cost shared at the same ratio as the original cost
sharing for the project. Cost sharing for navigation and hydropower projects may differ in accordance with USACE
authorities and policies. USACE, Safety of Dams—Policy and Procedures, ER 1110-2-1156, 2014, at
https://www.publications.usace.army.mil/Portals/76/Publications/EngineerRegulations/ER_1110-2-1156.pdf?ver=
2014-04-10-153209-550.
81 Section 1139 of the Water Infrastructure Improvements for the Nation Act (WIIN Act; P.L. 114-322) mandated the
issuance of guidance on the state-of-the-art provision, and in March 2019, USACE began to implement a new policy
that allows for the state-of-the-art provision across its dam portfolio.
82 Reclamation, Dam Safety Public Protection Guidelines: A Risk Framework to Support Dam Safety Decision-Making,
2011, at https://www.usbr.gov/ssle/damsafety/documents/PPG201108.pdf.
83 43 U.S.C. §509.
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additional project benefits, through the construction of new or supplementary works on a project
in conjunction with dam safety modifications, if such additional benefits are deemed necessary
and in the interests of the United States and the project. Nonfederal and federal funding
participants must agree to a cost share related to the additional project benefits. 84
The Commissioner of Reclamation also serves as the DOI’s chair for the DOI Working Group on
Dam Safety and Security and advises the Secretary of the Interior on program development and
operation of the dam safety programs within DOI.85 In this role, Reclamation provides training to
other DOI agencies with dam safety programs and responsibilities, and Reclamation’s dam safety
officer represents DOI on the ICODS.86
U.S. Forest Service87
The FS manages dams on its lands, within the National Forest System (NFS), and may authorize
nonfederal entities to use NFS lands for dams through a special use authorization (SUA; see box
on “Nonfederal Dams on Federal Lands”).88 In addition, dams managed by other federal agencies
(e.g., USACE, Reclamation) are located on NFS lands; the federal agency managing the dam has
responsibility for those dams.
FS policies provide for general requirements and procedures for FS dams, such as classification,
O&M plans, EAPs, and construction and design criteria.89 FS policy requires NFS units to have a
systematic dam inspection program, through which dams’ maintenance needs, hazardous
situations, operations, and other attributes are monitored.90 Any dam with “deficiencies that
significantly affect the integrity of the facility” must be repaired as soon as possible, or removed
from service until repairs can be made if needed to protect human life or surrounding lands and
resources.91 The FS also requires routine hazard assessments, through which consequences of
dam failure are evaluated.92
The FS typically uses general funding for capital improvement, maintenance, and deferred
maintenance,93 which includes dams, roads, structures, and other FS-managed infrastructure.
Therefore, funding for dams, particularly major maintenance or rehabilitation (i.e., activities that
cost more than $250,000), competes for funding along with other infrastructure projects in the

84 The costs associated with developing the additional project benefits are to be allocated exclusively among
beneficiaries of the additional project benefits and to be repaid consistent with provisions of Federal Reclamation law
(43 U.S.C. §§371 et seq.).
85 Reclamation, 2021 DOI Annual Report on Dam Safety, July 2022. To mitigate risks for DOI dams, Department
Manual Series 38, Part 753, “Dam Safety and Security Programs,” provides requirements and guidance to execute
DOI’s responsibility for dam safety, including the management of dam safety programs within BIA, BLM,
Reclamation, FWS, NPS, and OSMRE.
86 Personal correspondence between CRS and Reclamation, July 8, 2019.
87 This section was authored by Anne Riddle, analyst in natural resources policy.
88 The U.S. Forest Service (FS) may build and operate dams on National Forest System (NFS) lands in accordance with
the FS’s general authorities to plan and manage uses of the NFS (16 U.S.C. §§1600 et seq.; 16 U.S.C. §1601).
89 Forest Service Manual 7500, “Water Storage and Transmission” and subchapters.
90 FS Manual 7510, “Project Administration.” Inspection frequency is based on the hazard classification of the dam.
91 FS Manual 7530.1, “Construction.”
92 FS Manual 7510, “Project Administration.”
93 Deferred maintenance is defined as maintenance that was not performed as needed or scheduled and was put off to a
future time. See, for example, Financial Accounting Standards Advisory Board (FASAB), Statement of Federal
Financial Accounting Standards 42: Deferred Maintenance and Repairs: Amending Statements of Federal Financial
Accounting Standards 6, 14, 29 and 32, April 25, 2012, p. 5, at http://www.fasab.gov/pdffiles/handbook_sffas_42.pdf.
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FS’s capital improvement prioritization procedures.94 To the extent that FS dams have deferred
maintenance needs, they could be eligible for deferred maintenance funding provided in
discretionary or mandatory appropriations, such as mandatory funding from the National Parks
and Public Land Legacy Restoration Fund established by the Great American Outdoors Act.95
According to the agency, the FS attempts to prioritize its high hazard dams or addressing urgent
safety situations when determining how to use its limited resources.
Dam Rehabilitation and Repair on Tribal Lands
The Secretary of the Interior is responsible for the safety of all dams on Tribal lands in accordance with the Indian
Dams Safety Act of 1994, as amended (P.L. 103-302; 25 U.S.C. §§3801 et seq.). The Bureau of Indian Affairs (BIA)
is in charge of 126 high or significant hazard dams listed in the National Inventory of Dams (NID). The BIA dams
are on 43 tribal reservations. The average age of these dams is 70 years. In addition, there are over 700 additional
low hazard potential or unclassified dams (not listed in the NID) on tribal lands. While BIA maintains overall
responsibility, federally recognized tribes can operate and maintain dams on tribal lands under the Indian Self-
Determination and Education Assistance Act (ISDEAA, P.L. 93-638, as amended). Under ISDEAA, tribes can
request the authority to conduct certain activities that otherwise would be conducted by federal agencies.
Congress funds dam safety activities on tribal lands within the Resources Management Construction line item
under the BIA Construction account, which has received annual and supplemental appropriations (e.g., through
the Infrastructure Investment and Jobs Act; P.L. 117-58). In April 2016, the BIA testified to the U.S. Senate
Committee on Indian Affairs that $556 mil ion was needed for deferred maintenance and repairs of BIA dams,
with the backlog increasing by approximately 6% each year since 2010. Low hazard dams receive less federal
support and attention than high and significant hazard dams. The BIA reports that it is not aware of all low hazard
dams under its jurisdiction. The Water Infrastructure Improvements for the Nation Act (WIIN Act; P.L. 114-322)
established two Indian dam safety funds for the BIA to address deferred maintenance needs at eligible dams.
Eligible dams are those included in the BIA Safety of Dams Program established under the Indian Dams Safety Act
of 1994 that are either dams owned by the federal government and managed by the BIA or dams that have
deferred maintenance documented by the BIA. Over FY2017-FY2030, the WIIN Act, as amended by America’s
Water Infrastructure Act of 2018 (P.L. 115-270), authorized $22.75 mil ion per year for the High Hazard Indian
Dam Safety Deferred Maintenance Fund and $10 mil ion per year for the Low Hazard Indian Dam Safety Deferred
Maintenance Fund. As of FY2023, Congress has not provided appropriations to these funds to rehabilitate eligible
dams.
Source: Bureau of Indian Affairs, Reports to Congress to Meet the Requirements of the Water Infrastructure
Improvement for the Nation (WIIN) Act of 2016 Title III, Subtitle A—Safety of Dams and Subtitle B—Irrigation, 2017. The
number of high and significant hazard dams are from NID data accessed at https://nid.sec.usace.army.mil on
January 24, 2023, with data last updated on January 18, 2023.
Federal Oversight of Nonfederal Dams
Some federal agencies are involved in dam safety activities of nonfederal dams; these activities
may be regulatory or consist of voluntary coordination (see box on “Nonfederal Dams on Federal
Lands”).
Congress has enacted legislation to regulate hydropower projects, certain mining activities, and
nuclear facilities and materials.96 These largely nonfederal facilities and activities may utilize
dams for certain purposes. States also may have jurisdiction or ownership over these facilities,
activities, and associated dams, and therefore may oversee dam safety in coordination with
applicable federal regulations.97

94 FEMA, National Dam Safety Program, 2016-2017.
95 P.L. 116-152. For more information, see CRS In Focus IF11636, The Great American Outdoors Act (P.L. 116-152),
by Carol Hardy Vincent, Laura B. Comay, and Bill Heniff Jr.
96 FEMA, National Dam Safety Program, 2016-2017.
97 FEMA, National Dam Safety Program, 2016-2017.
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Nonfederal Dams on Federal Lands
In addition to federal dams on federal lands, there are also nonfederal dams on federal land. The NID as updated
in January 2023 reports that there are 1,766 nonfederal dams on federal lands. Most of these dams are located on
federal land management agencies’ land, although other agencies also have nonfederal dams located on their lands.
These dams were either constructed on federal lands under an agreement with the federal agency or constructed
on lands that were later acquired by the federal government. Federal agencies may have authorities for regulating
nonfederal dams on federal lands or may have policies outlining the division of responsibilities between federal
agencies and nonfederal entities as established through agreements. Some dams are inspected and regulated by the
relevant state government, depending on the state’s authority. Federal agencies may try to work with dam owners
whose dams are not regulated by federal or state agencies to carry out dam safety practices.
Regulation of Hydropower Dams
Under the Federal Power Act (16 U.S.C. §§791a-828c), FERC has the authority to issue licenses
for the construction and operation of hydroelectric projects, among other things.98 Many of these
projects involve dams, some of which may be owned by a state or local government. According to
FERC, the agency regulates over 2,500 dams.99 Of these, 1,754 are nonfederal dams listed in the
NID as of January 2023; 807 of these nonfederal dams are classified as high hazard, with 147 in
California, 86 in New York, and 69 in Michigan.100 Before FERC can issue a license, FERC
reviews and approves the designs and specifications of dams and other structures for the
hydropower project. Each license is for a stated number of years (generally 30-50 years), and
must undergo a relicensing process at the end of the license.
Along with nonfederal hydropower licensing, FERC is responsible for dam inspection during and
after construction.101 FERC staff are to inspect regulated dams at regular intervals.102 The owners
of projects with dams higher than 32.8 feet or with a total storage capacity of more than 2,000
acre-feet are required to contract independent consulting engineers, approved by FERC, for more
thorough inspections every five years.103 Should any inspection identify a deficiency, FERC

98 For inquiries related to FERC licensure, congressional clients may contact Kelsi Bracmort, CRS Specialist in Natural
Resources and Energy Policy. For more information, see CRS Report R42579, Hydropower: Federal and Nonfederal
Investment, by Kelsi Bracmort, Adam Vann, and Charles V. Stern.
99 FERC, Hydropower Primer, A Handbook of Hydropower Basics, February 2017, p.1, at https://www.ferc.gov/sites/
default/files/2020-05/hydropower-primer.pdf.
100 FEMA, National Dam Safety Program, 2016-2017; NID data accessed at https://nid.sec.usace.army.mil on January
24, 2023, with data last updated on January 18, 2023.
101 FERC requires licensees to prepare EAPs and conducts training sessions on how to develop and test these plans. For
more information on FERC’s dam safety activities, see FERC, “Dam Safety and Inspections,” at https://www.ferc.gov/
dam-safety-and-inspections.
102 According to 18 C.F.R. §12.4, a FERC representative may “test or inspect any water power project or project works
or require that the applicant or licensee perform such tests or inspections or install monitoring instruments” and
“require an applicant or a licensee to submit reports or information, regarding…the design, construction, operation,
maintenance, use, repair, or modification of a water power project or project works; and …any condition affecting the
safety of a project.” In 2019, FERC indicated that its staff inspect high hazard potential dams at least once per year,
significant hazard potential dams at least every one to three years, and low hazard potential dams at least every three to
six years. Personal correspondence between CRS and FERC, September 19, 2019. However, FERC noted that in 2020
and 2021, the agency did not perform all of its normal dam safety inspections due to the COVID-19 pandemic and
requested information from licensees through questionnaires or relied upon licensees to perform their own dam safety
inspections. FERC, Office of Energy Projects, Division of Dam Safety and Inspections, “2021 Annual Letter to
Licensees and Exemptees – Reminder of Responsibilities,” April 26, 2021, at https://cms.ferc.gov/media/2021-annual-
letter-licensees-and-exemptees-reminder-responsibilities, and “Annual Letter – Highlighted Items for 2022 and
Reminder of Responsibilities,” June 13, 2022, at https://cms.ferc.gov/media/annual-letter.
103 18 C.F.R. §12, subpart D.
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would require the project owner to submit a plan and schedule to remediate the deficiency.104
FERC then is to review, approve, and monitor the corrective actions until licensees have
addressed the deficiency.105 If a finding is highly critical, FERC has the authority to require risk-
reduction measures immediately; these measures often include reservoir drawdowns.106
FERC Response to Selected Hydropower Incidents
Following the spillway incident in 2017 at Oroville Dam, CA, a federal after-action panel and a
state forensic team released reports in 2018 that raised questions about the thoroughness of
FERC’s oversight of dam safety.107 Among other findings, the panel’s report concluded that the
established FERC inspection process, if properly implemented, would address most issues that
could result in a failure. However, the panel’s report stated that several failures occurred in the
last decade because certain technical details, such as spillway components and original design,
were overlooked and not addressed in the inspection or by the owner.108 A 2018 GAO review also
found that FERC had been prioritizing individual dam inspections and responses to urgent dam
safety incidents, but had not conducted portfolio-wide risk analyses.109 In response, FERC
reported in 2021 that it had completed a screening-level risk analysis of 754 high and significant
hazard dams in its portfolio and initiated 24 projects to address the risks it identified.110 In
addition, FERC produced draft guidelines in 2016 for RIDM, with a similar risk management
approach as USACE and Reclamation.111 FERC has allowed dam owners—generally those with a
portfolio of dams—to pilot RIDM, using the draft guidelines, for their inspections and prioritizing
rehabilitation and repairs instead of using the current deterministic, standards-based approach.112
Based on these evaluations and other reasons, FERC revised 18 C.F.R. §12, which went into
effect April 11, 2022.113 FERC revised the independent-consultant safety-inspection program,

104 The plan is due within 60 days of the findings.
105 FERC, Risk-Informed Decision Making.
106 FERC, Risk-Informed Decision Making.
107 California’s Department of Water Resources engaged an independent forensic team to develop findings and
opinions on the causes of the incident. FERC also convened an after-action panel to evaluate FERC’s dam safety
program at Oroville focusing on the original design, construction, and operations, including the five-year safety review
process. John W. France, Independent Forensic Team Report, Oroville Dam Spillway Incident, 2018, at
https://damsafety.org/sites/default/files/files/Independent%20Forensic%20Team%20Report%20Final%2001-05-18.pdf.
FERC After Action Panel, Assessment of Oroville Spillway Incident Causes and Recommendations to Improve
Effectiveness of the FERC Dam Safety Program, 2018, at https://www.ferc.gov/industries/hydropower/safety/projects/
oroville/12-06-18/report.pdf.
108 After the Oroville incident, a FERC-led initiative to examine dam structures comparable to those at Oroville Dam
identified 27 dam spillways at FERC-licensed facilities with varying degrees of safety concerns; FERC officials stated
they are working with dam licensees to address the deficiencies. GAO, Dam Safety: FERC Should Analyze Portfolio-
Wide Risks, GAO-19-19, at https://www.gao.gov/products/GAO-19-19. Hereinafter GAO, Dam Safety.
109 GAO, Dam Safety. FERC also identifies challenges with implementing a risk-informed dam safety program as a
regulatory agency compared to an agency that owns dams (e.g., USACE and Reclamation). FERC identifies that
complete adoption of risk-informed decisionmaking is dependent on amending regulations and policies, and the
capacity of industry to perform risk analysis. Personal correspondence between CRS and FERC, September 19, 2019.
110 GAO, Dam Safety.
111 FERC, Risk-Informed Decision Making (RIDM) Risk Guidelines for Dam Safety, 2016, at https://www.ferc.gov/
industries/hydropower/safety/guidelines/ridm.asp. See also, FERC, “Risk-Informed Decision Making (RIDM),” at
https://cms.ferc.gov/dam-safety-and-inspections/risk-informed-decision-making-ridm.
112 FERC, “Some Observations from FERC Risk Analysis Pilot Projects,” May 19, 2022, at https://cms.ferc.gov/media/
some-observations-ferc-risk-analysis-pilot-projects.
113 FERC, “FERC Finalizes Dam Safety Regulations,” December 16, 2021, at https://www.ferc.gov/news-events/news/
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described above, so that the required scope of these inspections alternates between a new, more
in-depth comprehensive assessment and a periodic inspection.
 Periodic inspections are to focus on the performance of the project over the
previous five years and include a field inspection, a review of project operations,
an in-depth review of monitoring data trends and behavior, and an evaluation of
whether any potential failure modes are occurring.114
 Comprehensive assessments are to include a deep dive into every aspect of a
project, including detailed review of the project’s design, engineering analyses,
and construction history; evaluation of spillway adequacy; potential failure mode
analysis; and risk analysis.115
The regulation update also changed the process by which FERC reviews and evaluates the
qualifications of independent consultants that conduct the inspections and assessments.
Inspections are now to be conducted by an independent consultant team, which may consist of
one or more independent consultants as well as additional supporting team members. The
regulation update also included revised safety incident reporting, revised definitions, and codified
FERC’s existing Owner’s Dam Safety Program requirement.116 In addition, FERC published four
new engineering guideline chapters that provide further guidance related to the regulatory
changes.117
Regulation of Dams Related to Mining
At mining sites, dams may be constructed for water supply, water treatment, sediment control, or
the disposal of mining byproducts and waste (i.e., tailings dams).
Under the Federal Mine Safety and Health Act of 1977, as amended (P.L. 91-173; 30 U.S.C.
§§801 et seq.), the Department of Labor’s Mine Safety and Health Administration (MSHA)
regulates private dams used in or resulting from mining.118 According to MSHA, approximately
1,640 dams are in its inventory. Of these, 520 are listed in the NID as of January 2023, with 255
classified as high hazard.119 As a regulator, MSHA develops standards and conducts reviews,

ferc-finalizes-dam-safety-regulations. FERC, “Safety of Water Power Projects and Project Works,” 87 Federal
Register 1490, January 11, 2022.
114 Federal Energy Regulatory Commission, Staff Presentation | Final Rule Regarding Safety of Water Power Projects
and Project Works, December 16, 2021.
115 Ibid.
116 In 2012, FERC established a requirement that owners of high and significant hazard dams prepare and maintain an
Owner’s Dam Safety Program, which formalizes a licensee’s policies and procedures related to organizational
oversight and responsibility, internal communication, resource allocation, and continuous improvement. FERC, Letter
to All Licensees and Exemptees of High and Significant Hazard Potential Dams Requiring Submittal of an Owner’s
Dam Safety Program, August 2012, at https://www.ferc.gov/sites/default/files/2020-04/letter-submit-odsp.pdf.
117 See Chapters 15-18 at FERC, “Engineering Guidelines for the Evaluation of Hydropower Projects,” at
https://www.ferc.gov/industries-data/hydropower/dam-safety-and-inspections/eng-guidelines.
118 P.L. 91-173, as amended by P.L. 95-164, (30 U.S.C. §801) directs that the “Secretary shall make inspections of each
underground coal or other mine in its entirety.” Impoundment facilities, retention dams, and tailings ponds are included
in the definition of a coal or other mine and are required to be included in these inspections. The Mine Safety and
Health Administration regulates dams under Title 30 of the Code of Federal Regulations. See Department of Labor,
Mine Safety and Health Administration, “Safety Topic: Impoundments and Dams,” at https://www.msha.gov/training-
education/safety-and-health-materials/safety-topic-impoundments-and-dams. For inquiries related to Mine Safety and
Health Administration regulations, congressional clients may contact Scott D. Szymendera, CRS Analyst in Disability
Policy.
119 NID data accessed at https://nid.sec.usace.army.mil on January 24, 2023, with data last updated on January 18,
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inspections, and investigations to ensure mine operators comply with those standards. According
to agency policies, MSHA is to inspect each surface mine and associated dams at least two times
a year and each underground mine and associated dams at least four times a year.120
Under Title V of the Surface Mining Control and Reclamation Act of 1977, as amended
(SMCRA; P.L. 95-87; 30 U.S.C. §§1251-1279), DOI’s Office of Surface Mining Reclamation and
Enforcement (OSMRE) administers the federal government’s responsibility to regulate active
coal mining operations to minimize environmental impacts during mining and to reclaim affected
lands and waters after mining.121 OSMRE regulations require coal mining operators to
demonstrate that dams are constructed, maintained, and removed in accordance with federal
standards (30 C.F.R. §715.18).122 According to the 2021 DOI Annual Report on Dam Safety,
OSMRE regulates 69 dams at coal mines under OSMRE’s federal and Indian lands regulatory
authority.123 Twenty-four states have primary regulatory authority (i.e., primacy) for dams under
SMCRA authority: for primacy, states must meet the requirements of SMCRA and be no less
effective than the federal regulations.124 If the dam is noncompliant with the approved design at
any time during construction or the life of the dam’s operation, OSMRE or the approved state
regulatory authority is to instruct the coal mining operator to correct the deficiency immediately
or cease operations.125
Regulation of Dams Related to Nuclear Facilities and Materials
The Nuclear Regulatory Commission (NRC) was established by the Energy Reorganization Act
of 1974 (P.L. 109-58; 42 U.S.C. §§5801 et seq.) as an independent federal agency to regulate and
license nuclear facilities and the use of nuclear materials as authorized by the Atomic Energy Act
of 1954, as amended (P.L. 83-703).126 Among its regulatory licensing responsibilities pertaining

2023.
120 FEMA, National Dam Safety Program, 2016-2017. According to FEMA’s National Dam Safety Program Biennial
Report to the United States Congress, Fiscal Years 2018 –2019, MSHA has a number of regulatory shortcomings as it
relates to tailings dams in the non-coal mining industry. Specifically MSHA does not require engineering design plans,
an independent review of plans, and does not define inspection frequency for owners/operators of non-coal-mine
tailings dams. In addition to inspecting existing dams, MSHA must approve the plans for certain new dams at coal
mines before construction can begin. 31 C.F.R. §77.216.
121 For inquiries related to the Office of Surface Mining Reclamation and Enforcement (OSMRE), congressional clients
may contact Lance Larson, CRS Analyst in Environmental Policy.
122 Current regulations do not require EAPs for OSMRE-regulated dams. According to the 2021 DOI Dam Safety
Report, OSMRE and the Solicitor’s Office have developed an opinion supporting OSMRE’s authority to prepare
regulations under the Surface Mining Control and Reclamation Act requiring EAPs and After Action Reports to be
included as requirements in surface coal mining permits consistent with the Federal Guidelines for Dam Safety.
123 Reclamation, 2021 DOI Annual Report on Dam Safety, July 2022. According to the report, current regulations do
not require EAPs for OSMRE-regulated dams, but OSMRE and the Solicitor’s Office have developed an opinion
supporting OSMRE’s authority to prepare regulations under the Surface Mining Control and Reclamation Act requiring
EAPs and After Action Reports to be included as requirements in surface coal mining permits consistent with the
Federal Guidelines for Dam Safety. States regulate dams under the state program. For more information on OSMRE’s
dam safety activities, see OSMRE, “Dam Safety,” at https://www.osmre.gov/programs/TDT/damsafety.shtm.
124 Section 503 of the Surface Mining Control and Reclamation Act of 1977, as amended (SMCRA; P.L. 95-87; 30
U.S.C. §1253).
125 FEMA, National Dam Safety Program, 2016-2017. 30 U.S.C. §1271 authorizes the Secretary of the Interior or the
Secretary’s authorized representative to immediately order a cessation of surface coal mining and reclamation
operations or the relevant portion thereof if a condition, practice, or violation creates an imminent danger to the health
or safety of the public, or is causing, or can reasonably be expected to cause significant, imminent environmental harm
to land, air, or water resources.
126 For inquiries related to the licensing and operations of uranium mining and milling, congressional clients may
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to dams, NRC regulates uranium mill tailings dams, storage water pond dams at in situ leach
(ISL) uranium recovery facilities, and dams integral to the operation of other licensed facilities
that may pose a radiological safety-related hazard should they fail.127 Currently, NRC directly
regulates seven dams.128 If NRC shares regulatory authority with another federal agency (e.g.,
FERC, USACE, Reclamation), NRC defers regulatory oversight of the dam to the other federal
agency.129 Under NRC’s authority to delegate regulatory authority, states may regulate dams
associated with nuclear activities based on agreements with NRC (i.e., agreement state
programs).130
Federal Support for Nonfederal Dams
Nonfederal dam owners generally are responsible for investing in the safety, rehabilitation, and
repair of their dams.131 In 2022, the Association of State Dam Safety Officials estimated that
$75.7 billion was needed to rehabilitate nonfederal dams; of that amount, $24.0 billion was
needed for high hazard potential nonfederal dams.132 Currently, 22 states provide a limited
amount of assistance for these activities (e.g., rehabilitation, repair) through grant or low-interest
revolving loan programs.133 Some federal programs may specifically provide limited assistance to
nonfederal dams that meet various eligibility criteria (e.g., the Small Watershed Rehabilitation
Program is only available to dams that were originally constructed with assistance from the
Natural Resources Conservation Service); these programs are in Table 4 and described in CRS
Report R47383, Federal Assistance for Nonfederal Dam Safety.134

contact Lance Larson, CRS Analyst in Environmental Policy. Regulation authorities are from the Atomic Energy Act
of 1954, as amended (P.L. 83-703); the Energy Reorganization Act of 1974, as amended (P.L. 93-438); and the
Uranium Mill Tailings Radiation Control Act of 1978, as amended (P.L. 95-604). FEMA, National Dam Safety
Program, 2016-2017.
127 Exceptions include dams that are submerged in other impoundments that do not pose flooding threats or dams
regulated by other federal agencies. Nuclear Regulatory Commission regulations are available at https://www.nrc.gov/
reading-rm/doc-collections/cfr/; 10 C.F.R. §40 includes regulations relating to impounding byproduct materials.
128 NID data accessed at https://nid.sec.usace.army.mil on January 24, 2023, with data last updated on January 18,
2023.
129 FEMA, National Dam Safety Program, 2016-2017. L. Joseph Callan, Status Report on Implementation of Dam
Safety Program, NRC, SECY-97-110, 1997, at https://www.nrc.gov/docs/ML1228/ML12284A135.pdf.
130 For more information on agreement state programs, see NRC, “Agreement State Program,” at https://www.nrc.gov/
about-nrc/state-tribal/agreement-states.html.
131 FEMA, National Dam Safety Program, 2016-2017.
132 ASDSO, The Cost of Rehabilitating Our Nation’s Dams, March 2022, at https://damsafety-prod.s3.amazonaws.com/
s3fs-public/files/Cost%20of%20Rehab%20Report-2022%20FINAL.pdf. There were 13,676 high hazard potential dams
in the NID, as of a November 3, 2022, update. 11,538 dams did not have a hazard potential classification (i.e., there
was no indication of whether the dam has a high, significant, or low hazard classification).
133 The number of states with a grant or loan program was self-reported by states through a State Dam Safety Program
Performance Questionnaire conducted by ASDSO in 2021. Personal correspondence between CRS and ASDSO,
October 17, 2022.
134 In addition, more general federal programs, such as the Community Development Block Grant Program, offer
broader funding opportunities for which dam rehabilitation and repair may qualify under certain criteria.
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Table 4.Selected Federal Programs That May Support
Nonfederal Dam Safety Projects
Agency
Program
Type of Federal Assistance
Federal Emergency Rehabilitation of High Hazard Potential Dam Grant
Grant
Management
Program
Agency
Flood Mitigation Assistance Program
Grant
Hazard Mitigation Grant Program
Grant
Building Resilient Infrastructure and Communities
Grant
Program
Safeguarding Tomorrow Revolving Loan Fund
Grants to capitalize state revolving
Program
funds
U.S. Army Corps
Corps Water Infrastructure Financing Program
Credit assistance, such as secured
of Engineers
loans or loan guarantees
P.L. 84-99 Rehabilitation Program
Repair of damaged flood control
works
Natural Resources Small Watershed Rehabilitation Program
Grant
Conservation
Service
Department of
Maintaining and Enhancing Hydroelectricity
Incentive payment
Energy
Incentives
Source: CRS.
Notes: For more information on these programs, see CRS Report R47383, Federal Assistance for Nonfederal Dam
Safety.
Issues for Congress
Congress may consider oversight and legislation relating to dam safety in the larger framework of
infrastructure improvements and risk management or as an exclusive area of interest. The
following sections discuss selected issues that may be of interest. Some of these issues relate to
many of the nation’s dams and the federal agencies involved in their dam safety activities (e.g.,
security issues). Other issues focus on specific types of dams (e.g., dams eligible for funding from
the Infrastructure Investment and Jobs Act [IIJA; P.L. 117-58]) or specific federal agencies (e.g.,
the National Oceanic and Atmospheric Administration [NOAA] updating methodologies for
probable maximum precipitation studies). In some cases, certain federal agencies have pioneered
new policies or approaches to dam safety activities (e.g., USACE disclosing inundation map data
for most of its facilities; FERC changing regulations to address risk considerations) that Congress
may be interested in evaluating and potentially facilitating adoption by other federal agencies. If
Congress chooses to address a certain dam safety issue, Congress may first consider which dams
and federal agencies are the focus of that issue, then strategize legislation and oversight efforts
targeting those dams and/or agencies.
Federal Role and Funding for Dam Safety Activities
Since the 1970s, the federal government has developed and overseen national dam safety
standards, and it has increasingly provided technical and grant assistance for nonfederal dam
safety. These activities, as well as the enhancement of federal agencies’ dam safety programs,
have improved certain dam safety metrics; nonetheless, deficiencies in federal and state programs
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may have contributed to recent incidents. Congress may consider oversight activities related to
federal implementation of dam safety practices. For example, in 2017, the Senate Committee on
Appropriations directed USACE, Reclamation, and FERC to brief the Senate Committee on
Appropriations on efforts to incorporate lessons learned from the failure of Oroville Dam’s
spillway into dam inspection protocols across all three agencies and their state partners.135
Although incidents and reviews may result in recommending improvements to federal dam safety
programs, some agencies have reported financial and other limitations to revising or expanding
their dam safety programs.136 Congress may consider these obstacles in determining whether new
authorities or appropriations are needed. For example, in the 117th Congress, the Twenty-First
Century Dams Act (H.R. 4375/S. 2356) would have authorized a national dam inspection
program and a national dam assessment, in addition to increasing authorization of appropriations
for various federal agency dam activities and programs.
Individual dam O&M, rehabilitation, and repair costs can range from thousands to hundreds of
millions of dollars.137 The responsibility for these expenses lies with dam owners; however, many
nonfederal dam owners are not willing or able to fund these costs.138 Although some states have
created a state-funded grant or low-interest revolving loan program to assist dam owners with
repairs, ASDSO notes that existing programs seem to vary significantly in the scope and reach of
available financial assistance.139 Some stakeholders suggest another financial mechanism for
supporting dam safety would be public-private partnerships, particularly supported by
beneficiaries of dam services.140 Congress provides regular appropriations for federal agency dam
safety activities and programs, and in the 117th Congress, the IIJA provided an influx of funding
for some of these and other programs that may support dam safety.
Infrastructure Investment and Jobs Act
The IIJA provided supplemental appropriations to Reclamation’s dam safety program, to the
NDSP for its activities and grants, and for programs that may support nonfederal dam safety
projects (see Table 5).

135 The Senate Committee on Appropriations report (S.Rept. 115-132) accompanying the Energy and Water
Development Appropriations Bill, 2018 (S. 1609), further instructed that the briefing include analysis of the Forensic
Investigation Team report examining the causes of the Oroville Dam spillway failures; the utility of a subsequent
independent panel to evaluate whether the USACE, Reclamation, and FERC should revise their dam safety procedures
in light of lessons learned from the Oroville incident; whether additional safety inspections should be required after
large storms; whether the projected effects of climate change and atmospheric rivers are appropriately considered in
safety requirements and testing protocols; whether new noninvasive structural health monitoring technologies have the
potential to improve safety inspections; and whether additional actions should be taken to ensure the safety of dams
without emergency spillways.
136 FEMA, National Dam Safety Program, 2016-2017.
137 ASDSO, Cost of Rehabilitating.
138 ASDSO, Cost of Rehabilitating; written testimony submitted by American Rivers for U.S. Congress, Senate
Committee on Environment and Public Works, Flood Control Infrastructure: Safety Questions Raised by Current
Events, 115th Cong., 1st sess., March 1, 2017.
139 Personal correspondence between CRS and ASDSO, October 2, 2019.
140 “Dam Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference,
Baltimore, MD, September 20, 2022.
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Table 5.Selected IIJA Funding for Dam Safety Activities
Agency
Program/Activity
IIJA Funding
Bureau of Indian Affairs
Construction, repair, improvement, and maintenance of $250 mil ion
irrigation and power systems, safety of dams, water
sanitation, and other facilities
Bureau of Reclamation
Safety of Dams Program
$500 mil ion
Department of Energy
Maintaining and Enhancing Hydroelectricity Incentives
$554 mil ion
Federal Emergency
National Dam Safety Program (activities and assistance
$67 mil ion
Management Agency
to states)
National Dam Safety Program (grants to state dam
$148 mil ion
safety programs)
Rehabilitation of High Hazard Potential Dam Grant
$585 mil ion, of which $75
Program
mil ion is for dam removal
Natural Resources
Small Watershed Rehabilitation Program
$118 mil ion
Conservation Service
U.S. Army Corps of
Corps Water Infrastructure Financing Program
$75 mil ion, of which $65
Engineers
mil ion is for the cost of
direct or guaranteed loans
and $11 mil ion is for
administrative expenses
Source: CRS.
Notes: IIJA = Infrastructure Investment and Jobs Act (P.L. 117-58). Appropriations were made available in
FY2022 except for some portions of appropriations from the Bureau of Indian Affairs, Bureau of Reclamation,
and Department of Energy, which are to become available in subsequent fiscal years. All appropriations are to
remain available until expended except funding for the National Dam Safety Program for activities and assistance
to states (available until FY2026). Some of these programs are specific to dam safety activities, while dam safety is
one of multiple eligible activities for others.
Congress may conduct oversight of these agencies’ use of the appropriated funds, which may be
in different stages of implementation. For example, Reclamation has released spend plans for
FY2022 through FY2023,141 whereas other agencies are first developing policy and procedures
for new programs (e.g., USACE’s proposed rule for the Corps Water Infrastructure Financing
Program and request for information for DOE’s Maintaining and Enhancing Hydroelectricity
Incentives).142 FEMA’s NDSP is conducting listening sessions in FY2023 to determine how best
to administer its funds based on the needs and capacity of state dam safety agencies and dam
owners.143 Some attendees of the initial sessions petitioned for flexibility to implement potential
increased grant funding (e.g., ability to use funding over multiple fiscal years), among other
concerns.
Another potential oversight issue includes agencies’ capacity to administer this level of awards,
contracts, and procurements and to perform project management and oversight. For example, in

141 Reclamation, “Bipartisan Infrastructure Law Investments,” at https://www.usbr.gov/bil/2022-spendplan.html.
142 USACE, “Credit Assistance and Related Fees for Water Resources Infrastructure Projects,” 87 Federal Register
35473, June 10, 2022. DOE, “Biden Administration Launches $630 Million in Programs to Modernize Nation’s
Hydropower Fleet,” June 30, 2022, at https://www.energy.gov/articles/biden-administration-launches-630-million-
programs-modernize-nations-hydropower-fleet.
143 “Dam Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference,
Baltimore, MD, September 20, 2022. FEMA, “Infrastructure Investment and Jobs Act (IIJA) Listening Sessions,” at
https://www.fema.gov/emergency-managers/risk-management/dam-safety/listening-sessions.
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December 2022, DOI described challenges in increasing staffing at Reclamation to implement
IIJA activities (e.g., hiring staff with necessary engineering and hydrology expertise).144 Congress
also may consider how to measure the effectiveness of these investments in improving national
dam safety and what future level of appropriations to provide to these activities and programs
while they implement IIJA funding. For example, Congress provided less funding to the Small
Watershed Rehabilitation Program in FY2022 and noted that the reduction was based on IIJA
additions.145
Adoption of Risk-Informed Decisionmaking
The dam safety community has increasingly espoused the benefits of shifting dam safety
programs from a standards-based approach to an RIDM approach; however, many programs face
hurdles to implementing RIDM policies.146 Reclamation and USACE were the first agencies to
implement RIDM management; these agencies also have more resources and expertise to manage
their large dam portfolios than most other federal and state agencies. Following the 2017 incident
at Oroville Dam, some federal and state agencies have increased efforts to incorporate RIDM into
management of their dam safety portfolios. For example, FERC has allowed owners to pilot
RIDM using draft guidelines it published in 2016, and the agency updated its regulations in 2022
to include comprehensive inspections in its inspection program, among other updates. Colorado’s
Dam Safety Program has developed comprehensive dam safety evaluation tools to enable
potential failure mode analysis and has created semi-quantitative risk assessment analyses to
enable repeatable assessments across its regulatory dam portfolio.147 While dam safety experts
say RIDM and its components (e.g., comprehensive assessments) are needed to prevent incidents
such as those experienced recently,148 incorporating these practices may require development of
new guidelines, certain personnel expertise, and more financial resources.149 For example,
comprehensive assessments are more costly than visual inspections and can require certain
inspection expertise.
Congress may consider whether, and if so how, to support the adoption and implementation of
RIDM approaches for dam safety. For example, Congress may conduct oversight of the NDSP’s
efforts to support dam safety agencies’ and communities’ adoption of RIDM policies. In
September 2022, FEMA stated that the NDSRB’s working group on risk was developing a risk
matrix and respective tools and training for dam agencies to implement the matrix.150 FEMA

144 Testimony from Deputy Secretary of the U.S. Department of the Interior (DOI) the Honorable Tommy P.
Beaudreau, in U.S. Congress, Senate Committee on Energy and Natural Resources, Full Committee Hearing to
Examine the Department of the Interior’s Implementation of the Infrastructure Investment and Jobs Act, hearings, 117th
Cong., 2nd sess., December 13, 2022, at https://www.energy.senate.gov/hearings/2022/12/full-committee-oversight-
hearing-to-examine-the-department-of-the-interior-s-implementation-of-the-infrastructure-investment-and-jobs-act.
145 Explanatory statement submitted by Mr. Leahy, Chair of the Senate Committee on Appropriations, regarding H.R.
2617, Consolidated Appropriations Act, 2023,” Congressional Record, vol. 168, part 198 (December 20, 2022), p.
S7826.
146 “Dam Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference,
Baltimore, MD, September 20, 2022.
147 Colorado Division of Water Resources, “Dam Safety,” at https://dwr.colorado.gov/services/dam-safety.
148 John W. France, et al. Independent Forensic Team Final Report, Investigation of Failures of Edenville and Sanford
Dams, May 2022, at https://damsafety-prod.s3.amazonaws.com/s3fs-public/files/Edenville-
Sanford_Final%20Report_Main%20Report%20and%20Appendices.pdf.
149 “Dam Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference,
Baltimore, MD, September 20, 2022.
150 Ibid.
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could update the Federal Guidelines for Dam Safety to further incorporate aspects of RIDM. IIJA
appropriations of $67 million for the NDSP supports authorized activities of the program, which
may include training and other activities to advance RIDM adoption and implementation. For
example, this IIJA funding could potentially support activities such as FEMA’s collaborative
technical assistance series, which is to help communities at risk of dam-related flooding to better
understand their risk landscape and the potential consequences of dam-related emergencies.151
Congress could also require certain aspects of RIDM policies in authorities for dam safety
programs. For example, the authority for the FEMA’s Rehabilitation of High Hazard Potential
Dam Grant Program requires that tribal or local governments with jurisdiction over the area in
which a dam receiving the grant is located has in place a hazard mitigation plan that includes all
dam risks and complies with the Disaster Mitigation Act of 2000 (P.L. 106-390).152 While these
requirements may ultimately improve RIDM practices, these requirements can result in
application burdens for communities that are unfamiliar with these policies or do not have the
resources to implement them.
Incorporating Future Conditions for Risk Management
Understanding how risk may change over time is also an aspect of RIDM. National probable
maximum precipitation (PMP) studies have long been used for regulation and design of
infrastructure, including dams, but the federal government has not updated PMP studies or
methodologies to capture precipitation patterns and events of recent decades and the potential
impacts of climate change.153 According to the World Meteorological Organization,
The objective of a probable maximum precipitation (PMP) estimate is to calculate the
probable maximum flood (PMF) used in the design of a given project at a particular
geographical location in a given watershed, and to further provide information that could
assist in designing the size (dam height and reservoir storage capacity) of the given project
and dimension of the flood-carrying structures (spillway and flood carrying tunnel) of the
project.154
NOAA first developed methodologies for estimating PMP in the 1940s and applied them across
the nation through studies in the late 20th century.155 State dam safety programs developed
statutes, rules, and guidance documents for the design of facilities partly based on these studies.156
Given that increased atmospheric moisture is an anticipated climate change effect, dam safety
officials and engineers have petitioned for updated extreme precipitation estimation tools that can
inform design and risk understanding of dams and associated structures under these future
conditions.157 NOAA has not officially updated these studies or methodologies to include new

151 FEMA has stated it aims to expand application of this assistance. Ibid and FEMA, “Dam Safety Collaborative
Technical Assistance,” at https://www.fema.gov/emergency-managers/risk-management/dam-safety/technical-
assistance.
152 33 U.S.C. §467f-2(d).
153 National Academy of Sciences, Engineering, and Medicine (NASEM), “Modernizing Probable Maximum
Precipitation Estimation (Committee Meeting #1),” February 16, 2023, at https://www.nationalacademies.org/event/02-
16-2023/modernizing-probable-maximum-precipitation-estimation-committee-meeting-1. Hereinafter NASEM, PMP
Committee Meeting #1, 2023.
154 World Meteorological Organization, Manual on Estimation of Probable Maximum Precipitation (PMP), WMO-No.
1045, 2009, at https://damfailures.org/wp-content/uploads/2020/10/WMO-1045-en.pdf.
155 National Oceanic and Atmospheric Administration (NOAA), “HDSC PMP Documents,” at
https://www.weather.gov/owp/hdsc_pmp.
156 ASDSO, “Roadmap to Reducing Dam Safety Risks,” at https://www.damsafety.org/Roadmap.
157 NASEM, PMP Committee Meeting #1, 2023. ASDSO, 2022-2027 Strategic Plan, at https://damsafety-
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methods, technologies, or decades of more recent storm data libraries.158 Some state dam safety
programs have started to employ new studies conducted by entities outside the federal
government,159 or have created methodologies to consider the range of impacts due to a changing
climate specific to their state.160 Others find these alternatives too difficult to attempt.161 Some
federal agencies have conducted site-specific PMP studies for certain facilities or are piloting
their own methodologies.162 For example, USACE has evaluated numerical weather model-based
precipitation maximization methods for areas dominated by atmospheric rivers.163 This varied
practice has led to inconsistencies between minimum dam-related design criteria, including for
repair and rehabilitation of dams and associated spillways, and understanding of risk among
federal and state agencies.164
IIJA provided appropriations for NOAA to develop “next-generation water modeling activities,
including modernized precipitation frequency and probable maximum studies.”165 This process is
starting with a National Academy of Sciences, Engineering, and Medicine (NASEM) study to
recommend an updated approach for estimating PMP in a changing climate, appropriate for
decision-maker needs.166 The Providing Research and Estimates of Changes in Precipitation Act
(PRECIP Act; Division D of P.L. 117-229) authorized this study, including certain study
requirements. The act also directed NOAA to
 develop and publish a national guidance document two years after the study, to
be updated at least every 10 years, that provides best practices that can be
followed by regulatory agencies and other users;
 update and publish PMP estimates for the nation 6 years after the study and
updated at least every 10 years; and
 conduct research in the field of extreme precipitation estimation with partners.

prod.s3.amazonaws.com/s3fs-public/files/ASDSO%202022-2027%20Strategic%20Plan_FINAL_0.pdf.
158 ASDSO, “Roadmap to Reducing Dam Safety Risks,” at https://www.damsafety.org/Roadmap.
159 For example, see selected studies by Applied Weather Associates at “AWA Current and Recently Completed
Projects,” at https://www.appliedweatherassociates.com/awa-projects.html.
160 For example, Colorado partnered with NOAA in order to determine an atmospheric moisture factor to add to
probable maximum precipitation values to capture potential future conditions. The Colorado – New Mexico Regional
Extreme Precipitation Study results provide engineers with tools to estimate extreme precipitation for spillway design
across the state of Colorado. Colorado Division of Water Resources, “Dam Safety,” at https://dwr.colorado.gov/
services/dam-safety. New Mexico Office of the State Engineer, “CO-NM Regional Extreme Precipitation Study (CO-
NM REPS) Final Reports,” at https://www.ose.state.nm.us/dams/conmpf_reports.php.
161 “Dam Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference,
Baltimore, MD, September 20, 2022.
162 NASEM, PMP Committee Meeting #1, 2023.
163 For more information on atmospheric rivers, see CRS Insight IN12094, Atmospheric Rivers: Background and
Forecasting, by Eva Lipiec and Nicole T. Carter. Yusuke Hiraga, et al., “Comparison of Model-Based Precipitation
Maximization Methods: Moisture Optimization Method, Storm Transposition Method, and Their Combination,”
Journal of Hydrologic Engineering, vol. 28, no. 1 (January 2023).
164 NASEM, PMP Committee Meeting #1, 2023. ASDSO, “Roadmap to Reducing Dam Safety Risks,” at
https://www.damsafety.org/Roadmap.
165 IIJA appropriated $492 million to NOAA for this and “coastal and inland flood and inundation mapping and
forecasting.” NOAA, “Flood and Inundation Mapping and Forecasting,” at https://www.noaa.gov/infrastructure-law/
infrastructure-law-climate-data-and-services/flood-and-inundation-mapping-and-forecasting.
166 NASEM, “Modernizing Probable Maximum Precipitation Estimation,” at https://www.nationalacademies.org/our-
work/modernizing-probable-maximum-precipitation-estimation.
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Despite these efforts, concerns remain that NOAA will not update these methodologies in time to
be included into FEMA’s and others’ efforts to update their policies and products or to be
considered in infrastructure investments funded by the IIJA and other federal appropriations.167
Congress could conduct oversight of NOAA’s progress on updating PMP methodologies and
studies. Further, Congress could direct NOAA to issue interim guidance to practitioners in the
short-term,168 or to use funding to support nonfederal entities’ development of targeted PMP
studies.169 However, regulations for dams informed by PMP studies may impact long-term and
costly decisions in dam design and rehabilitation;170 therefore, employing interim methodologies
prior to NOAA’s anticipated methodologies may ultimately result in further inconstancies and
debate regarding these decisions.
Dam Public Awareness and Security Issues
According to some advocacy groups, many Americans are unaware that they live upstream or
downstream of a dam.171 Further, if they are aware, the public may not know if a dam is deficient,
has an EAP, or could cause destruction if it failed.172 A lack of public awareness may stem from a
lack of access to certain dam safety information, the public’s confidence in dam integrity, or other
reasons.173 Dam safety processes and products (such as inspections, EAPs, and inundation maps)
are intended to support decisionmaking and enhance community resilience. Some of the
information related to dam safety and resulting products may not be readily available to all
community members and stakeholders because access to dam safety information has generally
restricted from public access due to security concerns.174
The September 11, 2001, terrorist attacks drew attention to the security of many facilities, such as
the nation’s water supply and water quality infrastructure, including dams. Damage or destruction
of a dam by a malicious attack (e.g., terrorist attack, cyberattack) could disrupt the delivery of
water resource services, threaten public health and the environment, or result in catastrophic
flooding and loss of life. As a consequence of the September 11, 2001, terrorist attacks, federal
policy and practices restricted public access to most information related to the condition
assessment of dams and consequences of dam or component failure. For example, according to
USACE, it had limited data regarding condition assessments for dams in the NID stating that they
met the definition of a vulnerability assessment of critical infrastructure as defined by the

167 “Dam Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference,
Baltimore, MD, September 20, 2022. NASEM, PMP Committee Meeting #1, 2023.
168 In September 2022, the Director of FEMA’s National Dam Safety Program stated that it inquired about interim
guidance from NOAA, to which NOAA responded no; however, FEMA stated the agencies meet monthly. “Dam
Safety 3.0 – Changing Our Paradigm,” general session at the ASDSO Dam Safety 2022 Conference, Baltimore, MD,
September 20, 2022.
169 For example, Section 40004 of P.L. 117-169, commonly referred to as the Inflation Reduction Act, appropriated
$200 million to NOAA to “support advancements and improvements in research, observation systems, modeling,
forecasting, assessments, and dissemination of information related to weather, coasts, oceans, and climate, including
climate research.” The White House, Building a Clean Energy Economy: A Guidebook to the Inflation Reduction Act’s
Investments in Clean Energy and Climate Action, January 2023, notes that $50 million of this funding is for grants.
Grants could support nonfederal entities’ development of targeted PMP studies.
170 NASEM, PMP Committee Meeting #1, 2023.
171 Written testimony submitted by American Rivers for U.S. Congress, Senate Committee on Environment and Public
Works, Flood Control Infrastructure: Safety Questions Raised by Current Events, 115th Cong., 1st sess., March 1, 2017.
172 ASDSO, “State Performance and Current Issues,” at https://damsafety.org/state-performance.
173 Baecher et al., Review and Evaluation, University of Maryland.
174 National Research Council, Dam and Levee Safety.
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Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and
Obstruct Terrorism (USA PATRIOT) Act of 2001 (P.L. 107-56).175 Then the NDSRB
recommended in FY2017 for USACE to consider modifying security restrictions in the NID.176 In
November 2021, USACE updated the NID to no longer restrict data, including condition
assessments and other risk-related information.177 Still, some states do not publicly report certain
data (e.g., Alabama and Illinois do not publicly report condition assessment data, and Texas does
not publicly report hazard potential), so this information is not included in the NID.178
Congress may consider reevaluating the appropriate amount of information to share (e.g.,
inundation scenarios from dam failure) to address public safety concerns and what amount and
type of information not to share to address concerns about malicious use of that information.
There are tradeoffs involved in sharing certain types of data. For example, sharing inundation-
mapping data with the public may raise awareness of the potential risk of living near or
downstream of a dam, but misinterpretation of that information could cause unnecessary alarm in
downstream communities and could provide information to malicious entities on which dams
would have the most potential for harm if attacked.179 Inundation-mapping data generally have
typically been shared with emergency managers and responders rather than with the public at
large.180 Some argue that disclosure to these officials is sufficient, as it provides the information
to the officials who bear responsibilities for emergency response.181 Others argue the need for this
information to be public so that communities better understand risk and improve local land use
planning. In 2020, USACE changed its policy that, when inundation mapping is available, it is
shared with the public.182 Accordingly, in January 2022, USACE made inundation mapping for
most of its dams available online through the NID.183 USACE is also conducting a pilot project
with California, Colorado, and New York for these states to host inundation maps of certain dams
that they own and/or regulate on the NID.184

175 Section 1016 of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and
Obstruct Terrorism (USA PATRIOT) Act of 2001 (P.L. 107-56) defines critical infrastructure as systems and assets,
whether physical or virtual, so vital to the United States that the incapacity or destruction of such systems and assets
would have a debilitating impact on security, national economic security, national public health or safety, or any
combination of those matters. According the Department of Homeland Security, a vulnerability assessment will
identify areas of weakness that could result in undesired consequences and will take into account intrinsic structural
weaknesses, protective measures, resilience, and redundancies. Department of Homeland Security, Dams Sector
Security Guidelines, 2015, at https://damsafety.org/sites/default/files/files/dams-sector-security-guidelines-2015-
508.pdf.
176 FEMA, National Dam Safety Program, 2016-2017.
177 National Inventory of Dams, “FAQS,” at https://nid.sec.usace.army.mil/#/what-is-nid/faqs.
178 Personal correspondence between CRS and USACE, August 5, 2022 and February 2, 2023.
179 Personal correspondence between CRS and FEMA, June 26, 2019.
180 Some states, such as Virginia, Wisconsin, and California, release potential inundation data to the public. FEMA,
National Dam Safety Program, 2016-2017. Baecher et al., Review and Evaluation, University of Maryland.
181 Baecher et al., Review and Evaluation, University of Maryland; U.S. Congress, House Committee on Transportation
and Infrastructure, Subcommittee on Economic Development, Public Buildings and Emergency Management,
Proposed Amendments to and Reauthorization of the National Dam Program Act, 109th Cong., 2nd sess., July 26, 2006.
182 USACE commanders can choose to withhold inundation maps as for official use only in situations where there are
significant security concerns. USACE, Inundation Maps and Emergency Action Plans and Incident Management for
Dams and Levee Systems, EC 1110-2-6075, October 1, 2020.
183 There may be no inundation map for a USACE dam where there is no potential loss of life or where the inundation
map is being updated or completed. Personal correspondence between CRS and USACE, August 5, 2022.
184 Personal correspondence between CRS and USACE, August 5, 2022.
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Efforts to Address Cybersecurity Risks
In addition to managing information flow to the public to address risk, Congress might consider
the risk of individuals or groups compromising dams and their operating infrastructure for
malicious purposes. This may include a physical attack or cyber intrusions to access and
manipulate dam industrial control systems for malicious purposes.185 In 2016, the Department of
Justice charged an Iranian national with obtaining unauthorized access into the supervisory
control and data acquisition systems of the Bowman Dam, located in Rye, NY, in August and
September of 2013. According to the indictment, the attackers gained access to information about
the status and operation of the dam, and would have been able to remotely operate the sluice gate
had it not already been manually disconnected for maintenance.186 This incident and others have
focused attention on the cybersecurity of dams and other critical infrastructure assets.187
In 2016, for the first time, Department of Homeland Security’s (DHS’s) Industrial Control
Systems Cyber Emergency Response Team included dams in its assessments along with other
types of infrastructure.188 A 2018 Department of the Interior Office of the Inspector General
(OIG) report highlighted poor security practices at two unnamed critical infrastructure dams
owned by Reclamation,189 and a 2022 Tennessee Valley Authority OIG report noted various issues
with the cybersecurity controls of the TVA’s non-power dam control system.190 In March 2023,
following a series of executive actions related to cybersecurity of critical infrastructure, the White
House released a new national cybersecurity strategy for the federal government to better support
the defense of critical infrastructure against emerging cybersecurity threats.191
DHS coordinates public-private partnerships for critical infrastructure security and resilience at
the federal level. The Dams Sector is one of 16 critical infrastructure sectors designated by

185 According to the National Institute of Standards and Technology, an industrial control system is an “information
system used to control industrial processes such as manufacturing, product handling, production, and distribution.
Industrial control systems include supervisory control and data acquisition systems used to control geographically
dispersed assets, as well as distributed control systems and smaller control systems using programmable logic
controllers to control localized processes.” NIST, Computer Security Resource Center Glossary, at https://csrc.nist.gov/
glossary/term/industrial_control_system.
186 Department of Justice, Office of Public Affairs, “Seven Iranians Working for Islamic Revolutionary Guard Corps-
Affiliated Entities Charged for Conducting Coordinated Campaign of Cyber Attacks Against U.S. Financial Sector,”
press release, March 24, 2016, https://www.justice.gov/opa/pr/seven-iranians-working-islamic-revolutionary-guard-
corps-affiliated-entities-charged.
187 See Department of Justice, “Seven Iranians Working for Islamic Revolutionary Guard Corps-Affiliated Entities
Charged for Conducting Coordinated Campaign of Cyber Attacks Against U.S. Financial Sector,” March 24, 2016, at
https://www.justice.gov/opa/pr/seven-iranians-working-islamic-revolutionary-guard-corps-affiliated-entities-charged.
188 National Cybersecurity and Communications Integration Center, ICS-CERT Annual Assessment Report, Industrial
Control Systems Cyber Emergency Response Team, FY 2016, https://www.cisa.gov/sites/default/files/Annual_Reports/
FY2016_Industrial_Control_Systems_Assessment_Summary_Report_S508C.pdf.
189 Office of the Inspector General, U.S. Department of the Interior, U.S. Bureau of Reclamation Selected Hydropower
Dams at Increased Risk from Insider Threats, 2017-ITA-023, June 2018, at https://www.oversight.gov/sites/default/
files/oig-reports/FinalEvaluation_ICSDams_Public.pdf.
190 Office of the Inspector General, Tennessee Valley Authority, Non-Power Dam Control System Cybersecurity, 2022-
17340, June 1, 2022, at https://www.oversight.gov/report/TVA/Non-Power-Dam-Control-System-Cybersecurity.
191 The strategy builds off Executive Order 14028, “Improving the Nation’s Cybersecurity,” 86 Federal Register
26633-26647, May 11, 2021 and other executive actions. For instance, the White House released a National Security
Memorandum on Improving Cybersecurity for Critical Infrastructure Control Systems on July 28, 2021, at
https://www.whitehouse.gov/briefing-room/statements-releases/2021/07/28/national-security-memorandum-on-
improving-cybersecurity-for-critical-infrastructure-control-systems/. White House, National Cybersecurity Strategy,
March 2023, at https://www.whitehouse.gov/wp-content/uploads/2023/03/National-Cybersecurity-Strategy-2023.pdf.
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link to page 21 link to page 21 Dam Safety Overview and the Federal Role

Presidential Policy Directive 21 (PPD-21) as having national-level significance to issues of
security, the economy, and public health.192 DHS is the Sector Risk Management Agency
(SRMA) for the Dams Sector, acting through the Cybersecurity and Infrastructure Security
Agency (CISA).193 As the SRMA, CISA is responsible for leading, facilitating, and supporting
the security and resilience of the Dams Sector. CISA provides technical assistance and training
opportunities, and guides sector partners and stakeholders through the Dams Sector Government
Coordinating Council (Dams Sector GCC)—a government interagency group—to help them
improve the safety, security, and resiliency of their facilities. The Dams Sector GCC coordinates
these activities via its private-sector counterpart, the Dams Sector Coordinating Council.194
A 2021 OIG report found that CISA could not demonstrate how its oversight has improved
security and resilience in the sector.195 The report raised a number of issues and recommendations
related to CISA’s lack of coordination and tracking of activities and performance, outdated sector
plans, gaps in information shared with FEMA, and not effectively using the Homeland Security
Information Network Critical Infrastructure Dams Portal—a DHS-run secure online information-
sharing and coordination site—to provide critical information to sector stakeholders.
Congress may consider various options for addressing the risk exposure of the nation’s dams to
cybersecurity threats. Congress may conduct oversight on CISA’s actions as the SRMA for the
Dams Sector and its response to recommendations from the 2021 OIG report. While CISA
concurred with all of the report’s recommendations, it is not clear if the agency has fulfilled its
commitments. For instance, one recommendation and concurrence was for CISA to update its
Dams Sector-Specific Plan by the end of FY2022; as of March 2023, the 2015 plan remains in
place.196 Congress could also consider enacting legislation to address certain specific
recommendations. For example, the report and ASDSO have recommended that CISA and
FEMA’s NDSP increase coordination.197 Congress could consider amending the National Dam
Safety Program Act to add CISA as a member of its advisory bodies (see “Advisory Bodies of the
National Dam Safety Program”) or to direct coordination between the agencies regarding
resilience and security.
The National Cybersecurity Strategy released by the Biden Administration in March 2023
outlines improving cybersecurity through new and updated regulations and through financial

192 Homeland Security Act of 2002 (P.L. 107-296) and Presidential Policy Directive (PPD) 21, “Critical Infrastructure
Security and Resilience.”
193 The dams sector, in this context, comprises dam projects, navigation locks, levees, hurricane barriers, mine tailings
impoundments, and other similar water retention and control facilities. Cybersecurity and Infrastructure Security
Agency (CISA), Dams Sector Overview, April 2021, at https://www.cisa.gov/sites/default/files/2023-01/dams-sector-
overview-042021-508.pdf. For more information on critical infrastructure issues, see CRS Report R45809, Critical
Infrastructure: Emerging Trends and Policy Considerations for Congress, by Brian E. Humphreys.
194 The Dams Sector Coordinating Council (SCC) is a self-run and self-governed organization of nonfederal owners
and operators and trade associations that represents the spectrum of assets within the sector. The Dams Government
Coordinating Council (GCC) acts as the government partner to the SCC to plan, implement, and execute sector wide
security programs for the sector’s assets. The GCC includes representatives from federal, state, local, and tribal owners
and operators, and federal and state regulators of sector assets. CISA, Dams Sector Overview, April 2021, at
https://www.cisa.gov/sites/default/files/2023-01/dams-sector-overview-042021-508.pdf.
195 Office of Inspector General, U.S. Department of Homeland Security, CISA Can Improve Efforts to Ensure Dam
Security and Resilience, OIG-21-59, September 9, 2021, at https://www.oig.dhs.gov/sites/default/files/assets/2021-09/
OIG-21-59-Sep21.pdf.
196 U.S. Department of Homeland Security, Dam Sector Specific Plan, 2015, at https://www.cisa.gov/sites/default/files/
publications/nipp-ssp-dams-2015-508.pdf.
197 ASDSO, “Roadmap to Reducing Dam Safety Risks,” at https://www.damsafety.org/Roadmap.
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Dam Safety Overview and the Federal Role

incentives, among other means.198 Since the majority of the nation’s dams are regulated by state
agencies, federal involvement in improving cybersecurity through regulations may be limited.
Congress may direct federal agencies that own dams to strengthen cybersecurity policies. It may
also direct FERC to require changes to mandatory cybersecurity reliability standards for the bulk
electricity system (including hydropower assets) developed and implemented by the North
American Electric Reliability Corporation (NERC), a nonprofit industry-led organization for
electric reliability. FERC exercises oversight of and provides guidance for the development and
implementation of NERC standards.199 Regarding nonfederal dams, FEMA could use
appropriations, including those provided by the IIJA, to support state agencies and nonfederal
dam owners in their efforts to improve dam cybersecurity. Congress could also amend existing
program authorizations or create new programs that authorize technical and/or financial
assistance for cybersecurity improvements at nonfederal dams. However, Congress may consider
trade-offs in using limited funds for security improvements if such a use detracts from
investments in dam safety actions such as inspections, rehabilitation, and repair.

Author Information

Anna E. Normand

Analyst in Natural Resources Policy

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
shared staff to congressional committees and Members of Congress. It operates solely at the behest of and
under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other
than public understanding of information that has been provided by CRS to Members of Congress in
connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not
subject to copyright protection in the United States. Any CRS Report may be reproduced and distributed in
its entirety without permission from CRS. However, as a CRS Report may include copyrighted images or
material from a third party, you may need to obtain the permission of the copyright holder if you wish to
copy or otherwise use copyrighted material.

198 The White House, “Fact Sheet: Biden-⁠Harris Administration Announces National Cybersecurity Strategy,” March 2,
2023, at https://www.whitehouse.gov/briefing-room/statements-releases/2023/03/02/fact-sheet-biden-harris-
administration-announces-national-cybersecurity-strategy/.
199 For additional information, see “Mandatory and Enforceable Critical Infrastructure Protection Standards” section in
CRS Report R46959, Evolving Electric Power Systems and Cybersecurity, by Richard J. Campbell.
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