The American Society of Civil Engineers' latest Infrastructure Report Card assigned US dams a grade of D, reflecting a maintenance and safety backlog that has grown to $76 billion across more than 91,000 dams nationwide. Of particular concern are 2,300 dams classified as high-hazard potential with deficient condition ratings — meaning these structures could cause loss of life if they failed and have known structural, hydraulic, or operational deficiencies that remain uncorrected.
The numbers tell a different story than the reassuring statistics about dam safety programs suggest. While catastrophic dam failures remain statistically rare — averaging 6 to 8 per year, mostly involving small privately owned dams — the concentration of deficient high-hazard dams in certain states and the age profile of the national dam portfolio point to an accelerating maintenance crisis that will drive significant construction spending over the coming decade.
The National Dam Portfolio
The National Inventory of Dams (NID), maintained by the US Army Corps of Engineers, catalogs 91,468 dams across the United States. The age distribution reveals the scale of the coming rehabilitation challenge. Dams over 50 years old number 56,700, representing 62% of the total. Dams over 75 years old total 23,400 at 26%. Dams over 100 years old number 7,200 at 8%. The average age of all US dams is 61 years, meaning the typical dam has already exceeded the 50-year design life used in most original engineering standards.
Hazard classification categorizes dams by downstream consequences of failure. High-hazard potential dams number 17,400 — failure would cause loss of life. Significant-hazard dams total 12,800 — failure would cause significant property or environmental damage. Low-hazard dams number 61,200 — minimal downstream consequences.
Of the 17,400 high-hazard dams, 2,300 (13.2%) have unsatisfactory or poor condition ratings from state dam safety inspections. These represent the most urgent construction and rehabilitation need. Additionally, many dams rated satisfactory were evaluated against outdated hydrologic and seismic criteria — when re-evaluated using current standards for Probable Maximum Flood (PMF) and Maximum Credible Earthquake (MCE), a significant percentage would be reclassified as deficient.
Rehabilitation Cost Categories
Dam rehabilitation construction spans several major categories, each requiring different contractor capabilities and equipment:
Spillway Rehabilitation is the most common need, addressing inadequate spillway capacity — the inability to safely pass updated flood estimates without overtopping the dam. Spillway work involves widening existing spillway channels using controlled rock blasting and excavation, deepening spillway approach channels to increase hydraulic capacity, constructing auxiliary spillways to supplement existing discharge capacity, installing labyrinth or piano-key weirs to increase discharge capacity within existing spillway width, and constructing new chute spillways with stilling basins for energy dissipation. Costs range from $2 million for minor modifications to $50 million for major auxiliary spillways at large dams. The Folsom Dam auxiliary spillway project in California cost $900 million, illustrating the extreme end of the cost spectrum for critical infrastructure.
Seepage and Foundation Remediation addresses internal erosion (piping), the leading cause of embankment dam failure. Remediation methods include cement-bentonite or soil-cement slurry cutoff walls installed through the dam and into the foundation using specialized hydrofraise or clamshell equipment, curtain grouting of fractured foundation rock using high-pressure cement or chemical grout injection, downstream seepage collection systems including toe drains, finger drains, and relief wells, and internal filter and drainage zone installation. Costs range from $1 million for simple grouting programs to $30 million for full cutoff wall installation through large embankment dams.
Structural Concrete Repair for concrete gravity dams, arch dams, and buttress dams experiencing deterioration from alkali-silica reaction (ASR), freeze-thaw damage, sulfate attack, or age-related cracking. Repair approaches include surface coatings and sealers for early-stage deterioration, epoxy crack injection for structural crack repair, post-tensioned rock and concrete anchors to restore structural stability, carbon fiber reinforced polymer (CFRP) strengthening, and in severe cases, upstream face reconstruction or buttress addition. Costs range from $500,000 for surface repairs to $100+ million for major structural stabilization of large concrete dams.
Embankment Modifications for the 83% of US dams built as earth or rockfill embankments. Common modifications include slope flattening to improve stability factors of safety, filter and drain installation to control internal seepage, crest raising to increase freeboard above updated flood levels, upstream slope armoring with riprap or articulated concrete block, and downstream toe berms for additional sliding resistance. These involve large-scale earthwork operations similar to levee construction, with costs ranging from $1 million to $40 million per dam.
Mechanical and Electrical Systems at dams with operable gates, valves, and spillway controls require periodic rehabilitation. Gate rehabilitation involves removing, refurbishing or replacing gates weighing 10 to 500+ tons, along with hydraulic operators, electrical controls, and emergency power systems. Costs range from $500,000 to $20 million per gate system, and many large dams have multiple gate structures.
Federal Dam Programs
Federal agencies own approximately 4,200 dams including many of the nation's largest:
US Army Corps of Engineers: 749 dams including 357 integrated with navigation locks. The Corps dam safety construction backlog exceeds $25 billion, with $3.2 billion provided through the IIJA. Annual dam safety construction spending is approximately $600 million, meaning the backlog is growing faster than projects are being completed.
Bureau of Reclamation: 491 dams in the western states providing irrigation, hydropower, and municipal supply. Reclamation's Safety of Dams program spends approximately $500 million annually, with a high-priority backlog exceeding $8 billion. Major active Reclamation dam safety projects include Scoggins Dam in Oregon at $780 million for a replacement dam, B.F. Sisk Dam in California at $1.2 billion for a dam raise and seismic stabilization, and Friant Dam spillway modifications at $350 million.
NRCS Watershed Dams: 11,800 small dams built primarily in the 1960s and 1970s for flood control and agricultural water supply. Over 2,000 have exceeded their 50-year design life. The IIJA provided $500 million for NRCS dam rehabilitation, but the backlog is estimated at $8 to $12 billion. Many of these dams will need to be either rehabilitated or decommissioned and removed.
FERC-Licensed Dams: 2,600 hydroelectric dams regulated by FERC, with safety maintenance funded by private dam owners. Annual dam safety construction spending by FERC licensees is approximately $1.5 to $2 billion.
State Programs and Non-Federal Dams
State dam safety programs regulate the remaining 87,000+ non-federal dams, with staffing that averages just 7 FTE per state overseeing an average of 1,800 dams per state. This regulatory capacity gap means many smaller dams receive infrequent inspection and limited enforcement of repair requirements.
States with dedicated dam rehabilitation funding include New York's Dam Safety Capital Grant Program, Pennsylvania's H2O PA program at $100 million, California's enforcement program backed by state bonds, and Massachusetts' Dam and Seawall Repair Fund at $30 million. Most states, however, lack dedicated funding, leaving repairs to dam owners who may be small municipalities, homeowner associations, or private individuals with limited financial capacity.
Construction Methods and Equipment
Dam rehabilitation construction requires specialized expertise and equipment. Roller Compacted Concrete (RCC) enables rapid placement of large concrete volumes using earthmoving equipment, achieving 3,000 to 8,000 cubic yards per day versus 500 to 1,500 for conventional methods. RCC is widely used for spillway construction and dam strengthening.
Deep cutoff wall construction uses hydrofraise (cutter-wheel) machines from manufacturers like Bauer and Soletanche Bachy to install continuous slurry walls 3 to 5 feet wide and 50 to 200+ feet deep through embankment fill and foundation materials. This is the most technically demanding dam construction specialty.
Controlled blasting for spillway rock excavation requires precision techniques to achieve design profiles without damaging adjacent dam structures — a skill set combining explosive engineering expertise with intimate understanding of dam structural behavior.
Workforce and Market Outlook
Dam rehabilitation construction employs an estimated 15,000 to 20,000 workers nationally. Key trades include heavy equipment operators, concrete workers, specialty foundation contractors, mechanical trades for gate systems, commercial divers for underwater inspection and repair, and instrumentation specialists.
The contractor market is concentrated, with firms like Kiewit, Barnard Construction, Ames Construction, Granite Construction, and specialized dam rehabilitation companies handling the majority of major projects. The primary barrier to entry is demonstrated experience — dam safety regulators require contractors with verifiable dam construction track records, making apprenticeship through subcontracting the most viable entry path.
The $76 billion national backlog represents multi-decade construction demand. With average age continuing to increase and hydrologic criteria being revised upward due to climate change, the dam rehabilitation market will grow rather than shrink. For construction firms with heavy civil capabilities and a willingness to develop dam-specific expertise, this is one of the most durable and well-funded construction market segments available.
Dam Removal: The Growing Alternative
An increasingly significant component of the dam construction market is dam removal — the controlled deconstruction of dams that are no longer economically justified, pose safety risks that exceed rehabilitation costs, or block fish passage in rivers targeted for ecological restoration.
Dam removal has accelerated dramatically in recent years. According to American Rivers, over 100 dams were removed in 2024, the highest annual total on record. While most removed dams are small (under 25 feet high), several major dam removal projects with construction values exceeding $50 million are underway or recently completed.
The largest dam removal project in history — the removal of four dams on the Klamath River in Oregon and California — was completed in 2024 at a cost of approximately $450 million. The project involved controlled drawdown of four reservoirs, demolition of concrete and earthfill dam structures ranging from 33 to 173 feet in height, management and stabilization of approximately 20 million cubic yards of accumulated reservoir sediment, and revegetation of over 2,000 acres of exposed reservoir bed.
Dam removal construction requires many of the same heavy civil capabilities as dam rehabilitation — earthmoving, concrete demolition, erosion control, environmental management — plus specialized expertise in sediment management and river restoration. For contractors, dam removal represents an emerging and growing market segment that complements traditional dam rehabilitation work.
Inspection Technology Advances
Advanced inspection technologies are improving the identification of dam deficiencies and reducing the cost of condition assessment. Drone-based photogrammetry and thermal imaging can identify seepage patterns, settlement, and structural distress on dam faces that are difficult to access for manual inspection. Distributed fiber optic sensing (DFOS) embedded in dam structures provides continuous monitoring of temperature, strain, and seepage — replacing periodic manual measurements with 24/7 automated monitoring. And satellite-based synthetic aperture radar (InSAR) can detect millimeter-scale dam movements over time, identifying potential stability concerns before they become visible to inspectors.
These technologies don't replace the need for construction — they accelerate the identification of dams requiring rehabilitation and provide better data for designing targeted repairs. For construction firms, the implication is a growing and more precisely defined pipeline of dam rehabilitation projects as inspection programs identify deficiencies more efficiently.
Climate Change Impact on Dam Safety Requirements
Climate change is creating a growing challenge for dam safety that will drive construction spending upward in coming years. Updated precipitation frequency analyses from NOAA Atlas 14 (and the forthcoming Atlas 15) show that rainfall events previously classified as the 100-year or 500-year storm are occurring more frequently — in some regions, what was once a 100-year event is now a 50-year or even 25-year event.
For dam safety, this means that dams designed to safely pass the Probable Maximum Flood (PMF) or a specific design flood (such as the 10,000-year event) based on historical data may now have inadequate spillway capacity. The implications are significant: an estimated 4,000 to 6,000 additional high-hazard dams may need spillway capacity upgrades as updated hydrology is applied to dam safety evaluations over the next decade.
The construction cost implications are substantial. Spillway capacity upgrades range from $2 million for minor modifications at small dams to $50 million or more for major auxiliary spillway construction at large dams. If even half of the estimated 4,000 to 6,000 dams requiring climate-updated hydrologic modifications proceed to construction, the total investment would be $10 to $20 billion — adding significantly to the existing $76 billion national backlog.
Tailings Dam Safety: A Growing Concern
The failure of Vale's Brumadinho tailings dam in Brazil in 2019, which killed 270 people, focused global attention on the safety of mining industry tailings storage facilities. The United States has approximately 1,800 tailings dams regulated under state dam safety programs, with an additional estimated 1,500 unregulated or inadequately regulated facilities.
The Global Industry Standard on Tailings Management (GISTM), adopted by major mining companies since 2020, is driving significant construction investment in tailings dam safety upgrades including buttress construction and slope flattening, improved drainage and seepage collection systems, advanced monitoring instrumentation, and in some cases, conversion from upstream to downstream or centerline construction methods that are inherently more stable. Annual tailings dam safety construction spending in the US is estimated at $500 million to $800 million, creating a specialized niche for contractors with both dam construction and mining industry experience.
Frequently Asked Questions
How much federal funding goes to dam repair construction spending?
According to the latest industry data, dam repair construction spending is showing notable trends in 2026. Current figures indicate $76 billion, which represents a significant benchmark for contractors and developers planning projects this year. Regional variations apply, so checking local market conditions remains essential for accurate budgeting.
Which states benefit most from dam repair construction spending?
The geographic landscape for dam repair construction spending is shifting in 2026. Data indicating 91,000 underscores the importance of market selection for contractors seeking growth. Western and southeastern states continue to attract disproportionate investment relative to their population share.
What is the timeline for dam repair construction spending projects?
Year-over-year comparisons for dam repair construction spending show meaningful change. The figure of 2,300 from current data represents a shift that contractors need to account for in their planning and bidding strategies. Historical trend analysis suggests this trajectory may continue through the end of the year.
