I. The Statutory Framework

The Federal Power Act (FPA), codified at 16 U.S.C. § 791a et seq., established the Federal Energy Regulatory Commission’s jurisdiction over the construction and operation of dams and other water-power projects on navigable waters of the United States, on public lands, and on federal reservations.¹ Section 4(e) of the Act, codified at 16 U.S.C. § 797(e), provides that the Commission “is authorized and empowered” to issue licenses for “the construction, operation, and maintenance of dams, water conduits, reservoirs, power houses, transmission lines, or other project works.”²

The statute’s jurisdictional reach is broad. It applies to any project that is “located on navigable waters of the United States,” that “occupies lands of the United States,” that “utilizes surplus water or water power from any Government dam,” or that is “located on any body of water over which Congress has jurisdiction under its authority to regulate commerce.”³ No exemption exists for structures built by nonhuman entities. No exemption exists for structures built without the intent to generate electricity. No exemption exists for structures built primarily for the storage of food and the avoidance of predators.

Simultaneously, Section 404 of the Clean Water Act, codified at 33 U.S.C. § 1344, prohibits the discharge of “dredged or fill material into the navigable waters” without a permit issued by the Secretary of the Army, acting through the Chief of Engineers.⁴ The Environmental Protection Agency defines “fill material” as any material “used for the primary purpose of replacing an aquatic area with dry land or of changing the bottom elevation of any body of water.”⁵

A beaver dam is a structure composed of mud, sticks, stones, and occasionally human debris, placed directly into a stream channel for the purpose of impounding water and changing the bottom elevation of a body of water. It is fill material by any reasonable reading of the regulation. The discharge is intentional. The placement is deliberate. The effect on navigable waters is documented. The permit is absent.

II. The Dam Operator

The North American beaver (Castor canadensis) is a semi-aquatic rodent weighing between 35 and 65 pounds, with a flat, scaly tail measuring approximately 12 inches in length and a bite force sufficient to fell a willow tree in under three minutes.⁶ It is the largest rodent native to North America, the second-largest rodent on Earth after the South American capybara, and the only rodent that constructs impoundment structures regulated under federal law.

The species is present in forty-nine of fifty United States.⁷ Hawaii is the sole state without a resident beaver population. The remaining forty-nine states each contain active dam construction operations conducted without federal oversight, state permits, or municipal building inspections. The operator does not maintain a registered agent in any jurisdiction. It does not file annual reports. It does not carry liability insurance. It does not respond to requests for information.

Prior to European colonization, the North American beaver population was estimated at 60 to 400 million individuals, maintaining as many as 65 million dams across the continent.⁸ The fur trade reduced this population to approximately 100,000 by the early twentieth century.⁹ Conservation and reintroduction programs have since restored the population to an estimated 6 to 12 million.¹⁰ This represents, in regulatory terms, the partial recovery of a previously suspended unlicensed dam construction program, funded by no federal appropriation and authorized by no federal agency.

III. The Scale of the Violation

The National Inventory of Dams, maintained by the U.S. Army Corps of Engineers under the authority of the National Dam Safety Program Act, catalogs 92,075 dams in the United States.¹¹ These are the dams that the federal government knows about. They have been surveyed, measured, classified, and in most cases inspected. The Federal Energy Regulatory Commission exercises direct safety oversight over 3,036 of them.¹² The Army Corps of Engineers itself manages 740.¹³

The North American beaver has constructed an estimated ten million dams currently in operation across the United States, a figure derived from population density estimates and observed dam-to-beaver ratios in surveyed watersheds.¹⁴ This means that for every dam in the National Inventory of Dams, there are approximately 109 beaver dams that the inventory does not contain. The unlicensed infrastructure outnumbers the licensed infrastructure by more than two orders of magnitude.

Individual beaver dams range in length from approximately 10 meters to more than 100 meters, with the longest known dam measuring 850 meters in Wood Buffalo National Park, Alberta, Canada, a structure visible from satellite imagery and confirmed by Guinness World Records as the largest structure ever built by a terrestrial animal.¹⁵ That dam impounds an estimated 70,000 cubic meters of water.¹⁶ A typical beaver pond in the United States holds approximately 1.1 million gallons of water.¹⁷

Taken together, the ten million beaver dams in the United States impound a volume of water that no federal agency has quantified, no state hydrological survey has measured, and no dam safety program has evaluated. The National Inventory of Dams tracks 92,075 structures. The untracked inventory is approximately 108 times larger. This is not a gap in the regulatory framework. This is the regulatory framework standing in a puddle and not looking down.

IV. The Section 404 Analysis

The construction of a beaver dam involves the systematic transport and placement of woody debris, sediment, stones, and organic matter into the channel of a flowing waterway, with the express purpose of obstructing flow and raising the upstream water surface elevation. Under 40 CFR § 230.2, any such placement constitutes a “discharge of fill material” subject to Section 404 permit requirements.¹⁸

The EPA’s guidelines at 40 CFR § 230.10 require that before a Section 404 permit may be issued, the applicant must demonstrate that there is no practicable alternative to the proposed discharge that would have less adverse impact on the aquatic ecosystem.¹⁹ A beaver constructing a dam has not conducted an alternatives analysis. It has not evaluated whether a less environmentally damaging location is available. It has selected its dam site based on stream gradient, water depth, and the proximity of aspen trees. These are not criteria recognized by the 404(b)(1) guidelines.

Section 404 permits are of two types: individual permits, which require site-specific review and public notice, and general permits (including Nationwide Permits), which authorize categories of activities with minimal environmental impact.²⁰ The Army Corps issues approximately 67,000 Section 404 authorizations per year across both categories.²¹ No beaver has ever applied for or received either type. The compliance rate among North American beavers is zero percent. This is the lowest compliance rate of any dam operator class in the history of Section 404 administration, a record that, in fairness, the beavers have held since 1972, when the statute was enacted, and since approximately 23 million years before that, when the genus Castor first appeared in the Oligocene fossil record.²²

V. The Dam Safety Inspection Gap

The National Dam Safety Program Act, 33 U.S.C. § 467 et seq., establishes a national program to reduce the risks of dam failure by ensuring that dams are regularly inspected, that emergency action plans are maintained, and that hazardous conditions are identified and remediated before catastrophic failure occurs.²³

Under the Act, the Federal Emergency Management Agency coordinates a national dam safety program in cooperation with state dam safety agencies. The Army Corps of Engineers classifies dams in the National Inventory by hazard potential: “high hazard” dams are those whose failure would result in probable loss of life; “significant hazard” dams are those whose failure would cause economic loss or environmental damage but no probable loss of life; “low hazard” dams are those whose failure would cause minimal consequences.²⁴

No beaver dam has ever been classified by hazard potential. No beaver dam has ever been inspected under the National Dam Safety Program. No emergency action plan has ever been filed for a beaver dam. This is despite the fact that beaver dam failures do occur, with documented consequences including downstream flooding, sediment mobilization, road washouts, and property damage.²⁵ A 2016 USGS study found that beaver dam failures can release impounded water in sudden, geomorphically significant flood pulses, producing outburst events analogous to the failure of small engineered dams.²⁶

The FERC Dam Safety Program conducts approximately 3,000 inspections per year across its portfolio of 3,036 licensed dams.²⁷ This represents a nearly one-to-one ratio of inspections to regulated structures. The beaver dam inventory of approximately ten million structures has received zero inspections. The inspection-to-structure ratio is not low. It is zero. An inspector assigned to the beaver dam portfolio at the FERC’s current inspection rate would require approximately 3,333 years to complete one full cycle.

VI. The Environmental Impact Statement Deficit

The National Environmental Policy Act (NEPA), 42 U.S.C. § 4332, requires that every “major Federal action significantly affecting the quality of the human environment” be accompanied by a detailed environmental impact statement (EIS) analyzing the proposed action’s environmental consequences, alternatives, and mitigation measures.²⁸

FERC has historically required environmental impact statements or environmental assessments for virtually every hydropower licensing decision. The licensing of a single small dam can generate an EIS exceeding 1,000 pages and require three to five years of study, public comment, and interagency consultation.²⁹ The total corpus of environmental review documents maintained in FERC’s eLibrary for its 3,036 licensed projects runs to millions of pages.

The North American beaver has prepared zero environmental impact statements. Zero environmental assessments. Zero findings of no significant impact. Zero biological assessments under Section 7 of the Endangered Species Act. Zero cultural resource surveys under Section 106 of the National Historic Preservation Act. The operator has not retained an environmental consulting firm. It has not posted a notice in the Federal Register inviting public comment on its proposed dam construction. It has not held a scoping meeting. It has not consulted with federally recognized Indian tribes regarding the potential effects of its activities on tribal resources.

The irony of this omission is acute. Beaver dams transform ecosystems. A single beaver pond can raise the local water table by several feet, convert flowing stream habitat to lentic wetland habitat, alter water temperature regimes, trap sediment, and modify nutrient cycling across an entire watershed.³⁰ These are precisely the kinds of environmental effects that NEPA was enacted to identify, evaluate, and disclose to the public. The effects are real. They are significant. They are occurring ten million times across forty-nine states. The paperwork documenting them does not exist.

VII. The Michigan Precedent

In 1997, the Michigan Department of Environmental Quality issued a notice to a landowner named Ryan DeVries in Montcalm County, directing him to cease and desist construction of two unauthorized dams on Spring Pond, which the agency determined were impeding the natural flow of a waterway in violation of Michigan environmental law.³¹

The dams had been constructed by beavers.

A neighbor, Stephen Tvedten, had filed the complaint after the beaver-impounded water flooded portions of his property. The DEQ, operating from aerial photography and field reports, attributed the structures to DeVries and demanded their removal under threat of a $10,000 fine. DeVries informed the agency that the dam builder was not a human being but a member of the family Castoridae, weighing approximately forty-five pounds and operating without a contractor’s license.

The agency eventually abandoned the enforcement action after determining that the beavers had left the site. The incident entered regulatory folklore not because it was anomalous but because it illustrated a structural problem that no administrative agency has resolved: the Clean Water Act, the dam safety statutes, and the state environmental codes assume a human operator. When the operator is a rodent, the enforcement mechanism fails at the identification stage. The agency could not issue a permit to the beaver. It could not negotiate a consent decree with the beaver. It could not assess a civil penalty against the beaver. The beaver had no mailing address, no registered agent, and no counsel. The beaver had a lodge.

The Michigan incident is the closest the American regulatory apparatus has come to confronting the beaver dam licensing gap directly. It identified the problem, attempted enforcement, discovered the nature of the regulated party, and withdrew. In the twenty-nine years since, no federal or state agency has attempted a more systematic approach. The beavers have continued building.

VIII. The Fish Passage Problem

Section 18 of the Federal Power Act, 16 U.S.C. § 811, authorizes the Secretary of the Interior and the Secretary of Commerce to prescribe fishways at any dam licensed by FERC.³² This authority is routinely exercised. FERC licenses for hydropower dams commonly include mandatory conditions requiring the construction and maintenance of fish ladders, fish elevators, or other passage structures to allow anadromous fish species to reach upstream spawning habitat.

Beaver dams obstruct fish passage. This is not a contested ecological finding. It is the reason the dam exists. The beaver builds its dam specifically to create a pond deep enough to submerge the entrance to its lodge, thereby excluding predators. The exclusion of upstream-migrating fish is a direct, intentional consequence of the dam’s design and placement.³³

Under Section 7 of the Endangered Species Act, 16 U.S.C. § 1536, any federal action that “may affect” a listed species requires formal consultation with the U.S. Fish and Wildlife Service or the National Marine Fisheries Service.³⁴ Beaver dams in the Pacific Northwest have been documented obstructing passage for ESA-listed steelhead trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch).³⁵ No Section 7 consultation has ever been initiated for a beaver dam. No biological opinion has ever been issued. No incidental take permit has ever been applied for by a beaver.

The regulatory paradox is immediate. If a human dam operator blocked fish passage to the same streams, FERC would require a fishway. The Fish and Wildlife Service would demand a biological assessment. The National Marine Fisheries Service would issue a biological opinion with mandatory reasonable and prudent measures. The operator would face potential liability under the ESA’s citizen suit provision, 16 U.S.C. § 1540(g). The beaver faces none of these consequences, not because its impact is smaller, but because no regulatory framework contemplates serving a Section 7 notice on a thirty-five-pound rodent with webbed feet.

IX. The Regulatory Paradox

The paradox deepens. While the beaver operates in continuous violation of the Federal Power Act, the Clean Water Act, the National Dam Safety Program Act, and arguably the Endangered Species Act, it is simultaneously the subject of federally funded restoration programs designed to increase the number of its unlicensed structures.

The USDA Forest Service has endorsed beaver dam analogues (BDAs), human-built structures designed to mimic beaver dams, as a restoration tool for degraded streams across the western United States.³⁶ The Bureau of Land Management has funded beaver reintroduction programs in Nevada, Utah, and Oregon. The State of California enacted a Beaver Restoration Program in 2023 to promote beaver-mediated habitat restoration as a climate adaptation strategy.³⁷ A 2024 multi-site study published in the journal Hydrological Processes found that beaver dams reduce peak storm flows by up to 60 percent, providing natural flood management benefits that engineered infrastructure cannot replicate at comparable cost.³⁸

The federal government is thus in the following position: it requires a FERC license for any dam built by a human on navigable waters; it requires a Section 404 permit for any fill material placed by a human in waters of the United States; it requires an environmental impact statement for any major federal action significantly affecting the environment; and it simultaneously funds programs to encourage a nonhuman entity to build dams, place fill material, and significantly affect the environment, all without any of these regulatory requirements.

The human who builds a beaver dam analogue must obtain a Section 404 permit. The beaver whose dam the analogue imitates does not. The human’s structure is subject to inspection. The beaver’s is not. The human’s structure is limited to the dimensions and locations specified in the permit. The beaver builds wherever and however it pleases. The government is simultaneously the regulator and the promoter of an unregulated activity. The cognitive dissonance is hydrological.

X. The Enforcement Impossibility

Under 18 CFR § 12.1, every dam subject to FERC jurisdiction must be operated and maintained in accordance with the terms and conditions of its license, and the Commission may require modifications, repairs, or removal of any project works that present a threat to public safety.³⁹ The enforcement toolkit includes civil penalties under 16 U.S.C. § 823b of up to $31,819 per violation per day, compliance orders, and in extreme cases, revocation of the project license.⁴⁰

None of these remedies can be applied to a beaver. The beaver has no license to revoke. A civil penalty assessed against a beaver would constitute an uncollectible judgment. A compliance order served on a beaver lodge would not be read, acknowledged, or obeyed. The beaver does not participate in administrative proceedings. It does not file motions. It does not attend prehearing conferences. It does not retain counsel, though given the complexity of the regulatory framework it is violating, it would benefit from doing so.

The Army Corps of Engineers has the authority under 33 U.S.C. § 1319 to issue administrative compliance orders for Clean Water Act violations, including unpermitted discharges of fill material. The maximum civil penalty is $64,618 per day per violation.⁴¹ Applied to the approximately ten million beaver dams in the United States, each representing a separate unpermitted discharge of fill material, the aggregate daily penalty exposure would be $646.18 billion. This exceeds the combined annual budgets of the Army Corps of Engineers, FERC, the EPA, and the Department of the Interior by a factor of approximately 11,000. The penalty would be assessed against a species with no known assets, no bank accounts, and no capacity to execute a payment instrument. The enforcement action would be the most expensive and least collectible in the history of federal environmental law.

Alternative enforcement approaches fare no better. Physical removal of beaver dams is a recognized management technique, but it is temporary. Studies have documented beavers rebuilding removed dams within 24 to 48 hours.⁴² An enforcement action that is undone by the respondent within two days is not an enforcement action. It is a demonstration of the respondent’s indifference to federal authority.

XI. The International Dimension

Beaver dam construction is not a domestic problem. Castor canadensis operates across the full extent of the North American continent, from Alaska to northern Mexico. The largest known beaver dam, the 850-meter structure in Wood Buffalo National Park, is in Alberta, Canada, built entirely without permits from Environment and Climate Change Canada, Fisheries and Oceans Canada, or the Alberta Energy Regulator.⁴³

The species has also been introduced to South America. In 1946, the Argentine government released twenty-five pairs of North American beavers in Tierra del Fuego to establish a fur industry. The beavers ignored the economic development plan. They built dams. By 2026, the population had expanded to an estimated 100,000 individuals occupying approximately 16 million hectares of Patagonian forest, constructing thousands of unpermitted dams across two countries and causing ecological damage estimated at $33 million in binational eradication costs alone.⁴⁴

No international treaty governs the transboundary construction of beaver dams. The International Joint Commission, which manages shared U.S.-Canadian water resources under the Boundary Waters Treaty of 1909, has jurisdiction over structures that affect water levels along the international boundary. Beaver dams in boundary watersheds meet this definition. The Commission has not addressed them. The beavers have not sought the Commission’s approval. They have not read the treaty. They have built their dams on both sides of the border, as they have been doing since before the border existed, and before the nations that drew it existed, and before the species that drew it existed.

XII. The Jurisdictional Void

The problem is not that the law lacks scope. The Federal Power Act covers dams on navigable waters. Section 404 covers fill material in waters of the United States. The Dam Safety Program Act covers hazardous dams. NEPA covers major actions affecting the environment. The ESA covers actions affecting listed species. The statutes are comprehensive. They reach every conceivable dam construction scenario that a 1972 Congress could have imagined. The scenario they did not imagine was one in which the dam builder cannot read, cannot be served with process, and communicates primarily by slapping its tail on the surface of the water.

FERC licenses 3,036 dams. The NID catalogs 92,075. Beavers have built approximately ten million. The ratio of regulated dams to unregulated beaver dams is approximately 1 to 109. The ratio of dam safety inspections to beaver dams is zero. The ratio of environmental impact statements prepared for beaver dams is zero. The ratio of Section 404 permits issued to beavers is zero. The ratio of fish passage prescriptions imposed on beaver dams is zero. The ratio of FERC applications filed by beavers is zero.

The most prolific dam operator in North American history is a thirty-five to sixty-five pound rodent with orange, iron-reinforced incisors, a flat tail, and a work ethic that the Army Corps of Engineers has never matched. It has been in continuous operation for approximately 23 million years. It operates in forty-nine states. It has constructed more dams than every human government, corporation, and utility in the Western Hemisphere combined. It has never received a license, a permit, a certificate of compliance, or a letter of no objection from any regulatory body in any jurisdiction on Earth.

The federal dam regulatory apparatus was built to govern human infrastructure. The infrastructure it does not govern is two orders of magnitude larger, operates around the clock, rebuilds itself within 48 hours of removal, and is, by the federal government’s own scientific assessments, more ecologically beneficial than the infrastructure it does regulate.

Ergo.