The U.S. Army Corps of Engineers determined that environmental mitigation was unnecessary for 52 water resources projects submitted to Congress between 2020 and 2025. But according to a new federal audit, the Corps failed to clearly document the statutory justification for those decisions in the reports it provided to lawmakers.
The Government Accountability Office’s October 8 report found that none of the Chief’s Reports covering those projects explicitly stated that the projects would have negligible adverse impacts on fish, wildlife, and ecological resources without mitigation. Nor did the reports explain how the Corps reached that conclusion.
The findings raise questions about the information Congress receives when considering federal water infrastructure projects, particularly those involving flood control, navigation improvements, and coastal storm protection.
The Army’s response adds another dimension to the problem. Despite Corps officials acknowledging that clearer documentation would benefit Congress and the public, senior Army leadership rejected GAO’s recommendation to develop additional guidance.
It is the latest in a series of federal audits identifying weaknesses in how the Corps documents, tracks, and oversees environmental mitigation.
Fifty-Two Projects, No Mitigation Plans
The Corps’ Civil Works program manages water resources infrastructure across the country, including levees, navigation channels, flood protection systems, and environmental restoration projects. Construction and maintenance activities can affect wetlands, waterways, wildlife habitats, and other ecological resources.
Under 33 U.S.C. § 2283(d)(1), the Corps must include one of two things in reports submitted to Congress for project authorization: a specific plan to mitigate environmental damage or a determination that the project will have negligible adverse impacts without mitigation.
GAO examined 74 Civil Works projects submitted for authorization between 2020 and 2025. Of those projects, 22 included mitigation plans. The remaining 52, approximately 70 percent, did not.
The absence of a mitigation plan does not necessarily indicate wrongdoing. Some projects, particularly those designed to restore ecosystems, may not require compensatory environmental measures.
However, 43 of the 52 projects without mitigation plans included navigation, flood-risk management, or coastal storm-risk management missions. Corps officials acknowledged that projects involving these activities are more likely to produce environmental impacts requiring mitigation. That makes the documentation supporting decisions to forego mitigation especially important.
GAO found that the Corps’ explanations frequently relied on broad statements about avoiding significant environmental impacts rather than explicitly addressing the negligible-impact standard established by federal law.
In its review of the Chief’s Reports, GAO found no clearly documented explanation of how the Corps determined that adverse impacts on ecological resources would be negligible. A separate examination of 14 supporting feasibility reports found that environmental information was often scattered across resource-specific discussions, making it difficult to determine whether the agency had considered all relevant ecological impacts.
GAO did not conclude that the 52 projects necessarily required mitigation or that their underlying environmental analyses were incorrect. Its finding concerned the clarity and completeness of the determinations presented for congressional consideration.
Army Officials Acknowledged the Problem. Leadership Rejected the Fix.
Perhaps the most revealing portion of the audit concerns the disagreement between Corps officials interviewed by GAO and the Army’s formal response.
According to GAO, Corps headquarters officials acknowledged that they had not consistently focused on presenting no-mitigation determinations and their underlying rationale in a clear summary format. The officials also acknowledged that the Corps had not issued internal guidance specifying how such determinations should be documented in Chief’s Reports and feasibility reports.
They told auditors that clearer documentation would likely benefit Congress and the public. GAO consequently recommended that the Assistant Secretary of the Army for Civil Works ensure that the Corps develop guidance for documenting and justifying decisions that environmental mitigation is unnecessary.
The Office of the Assistant Secretary rejected the recommendation.
In a September 16, 2026, letter reproduced in the report, D. Lee Forsgren, then serving as the senior official performing the duties of Assistant Secretary of the Army for Civil Works, maintained that existing reports already contained sufficient technical information for decision-makers, the public, and resource agencies.
GAO disputed that position. The auditors noted that the Army’s written response differed from statements Corps officials had provided during the audit and did not supply additional information sufficient to change GAO’s conclusion. GAO maintained its recommendation.
The disagreement leaves a straightforward accountability question: if Corps officials acknowledge that the required determinations are not consistently presented clearly, why is Army leadership unwilling to establish guidance to address the problem?
A Recurring Problem With Environmental Accountability
The October findings are not the first time federal auditors have identified weaknesses in the Corps’ environmental mitigation practices.
In September 2024, GAO issued a separate audit examining the Corps’ mitigation reporting and tracking. That investigation found that the Corps had not delivered required annual reports on the status of construction projects requiring mitigation to Congress after fiscal year 2020.
GAO also found that reports covering earlier years did not consistently include required information and that the Corps lacked a documented, uniform methodology for tracking and reporting mitigation activities. The deficiencies complicated efforts to determine whether mitigation was keeping pace with construction.
In one example, the Corps reported that 47 projects had successfully met compensatory mitigation requirements between fiscal years 2008 and 2020. Yet Corps officials told GAO that the agency did not maintain a list of completed mitigation projects that could be used to verify that total.
The Department of Defense agreed with GAO’s recommendation to establish uniform reporting policies. However, the recommendation remained open, with the Corps reporting in June 2026 that corrective work was continuing.
Another GAO report released in April 2026 examined the Corps’ oversight of compensatory mitigation under the Clean Water Act. That audit found improvements in certain oversight activities but also inconsistent implementation of requirements involving financial assurances, long-term management, and ecological performance standards.
In that case, Army leadership agreed to develop additional implementation guidance. An August 2026 corrective-action plan anticipated new templates by August 2027.
The audits examine different functions. The April report primarily concerns the Corps’ regulatory oversight of mitigation associated with permitted activities, while the October report addresses mitigation determinations for the Corps’ own Civil Works projects.
Nevertheless, the findings reveal recurring weaknesses involving documentation, guidance, and accountability across the agency’s environmental mitigation responsibilities. They also reveal differing responses from Army leadership: agreement to develop guidance in one program, but rejection of guidance intended to clarify statutory determinations in another.
Congress Also Lacks a Complete Picture of Mitigation Costs
The latest report identifies another significant information gap. GAO was unable to determine how environmental mitigation affects Civil Works project completion timelines because available data do not isolate mitigation-related delays from other factors.
The Corps also does not centrally collect comprehensive information showing how actual mitigation costs ultimately affect total project costs. Although some cost information exists in individual project files, the absence of comprehensive data limits the ability to evaluate the program’s financial consequences across projects.
Those limitations matter because environmental mitigation can involve land acquisition, habitat restoration, monitoring, long-term maintenance, and agreements with third-party mitigation providers. The Corps also commonly shares project costs with state and local sponsors.
Without comprehensive information, Congress faces limitations in evaluating the actual costs and scheduling effects of mitigation requirements across the Civil Works program. GAO did not calculate the amount of money potentially affected by these information gaps.
The Question Before Congress
The October audit does not establish that the Corps improperly avoided environmental mitigation on 52 projects. Nor does it demonstrate that those projects caused ecological damage.
What it establishes is a documentation failure involving a statutory safeguard intended to inform congressional authorization decisions. Congress requires the Corps to explain either how a project will mitigate environmental damage or why mitigation is unnecessary.
GAO found that the Corps’ reports generally failed to clearly communicate the latter determination and its justification. The problem is especially consequential because Congress relies on the agency’s technical assessments when deciding whether to authorize major water resources infrastructure.
The Corps may possess extensive environmental analyses supporting its decisions. But if the required determinations cannot be clearly identified and understood in the reports presented to Congress, lawmakers and the public face an avoidable obstacle to evaluating those decisions.
For now, Army leadership maintains that existing documentation is sufficient, while GAO continues to recommend a more explicit approach.
After multiple audits identifying deficiencies in environmental mitigation reporting, oversight, and documentation, the latest disagreement leaves Congress with a familiar problem: an agency asserting that its processes are adequate while federal auditors continue to find that the supporting information is not.
The Corps may have determined that additional environmental mitigation was unnecessary for those 52 projects. Whether it adequately explained those determinations to Congress is another matter entirely. The pattern of agencies asserting adequacy while auditors find gaps extends well beyond the Corps: GAO documented a similar dynamic at the U.S. Interagency Council on Homelessness, where prior GAO recommendations on governance and procedures remained unimplemented as of July 2026, and at the Postal Service, where Congress faces an agency it may have to bail out despite years of watchdog reporting on the underlying problems.
