Project Authorities Overview

Water Resource Projects Authorities Overview

Northwestern Division
Published Dec. 7, 2018

Original Authorities and Modifications Over Time

Since the 1800s, the U.S. Congress has authorized the U.S. Army Corps of Engineers to construct and operate water resource projects such as dams, navigation locks and levees to serve a variety of functions. From reducing flood risks, supporting commercial navigation, generating hydropower and providing water and facilities for fish and wildlife conservation, these purposes are laid out in the authorizing legislation specific to each project.

Once a project is completed, the Corps has limited discretion to make reasonable changes and additions to better serve the public interest and meet a project’s authorized purposes. Under certain circumstances, the Corps may use existing authorities to evaluate and modify projects, such as provided in Section 216 of the Flood Control Act of 1970 (as amended). However, when the Corps determines that significant modifications are advisable due to changes in economic or environmental conditions congressional authorization and appropriation is necessary.

Potential modifications of completed water resource projects that will result in major structural or operational change, or that will seriously affect authorized purposes require congressional authorization and appropriations. More information is available in the Corps’ Engineering Regulation (ER) 1165-2-119 Water Resources Policies and Authorities, Modifications to Completed Projects (Sept. 20, 1982) or ER 1105-2- 100, Appendix G, Section III Post Authorization Changes. 

Necessary Details

Seeking authorization from Congress starts with an evaluation that provides sufficient details for an authorization request. For example, the Corps must prepare the required designs to ensure the modification is performed in a manner that meets engineering, environmental and other statutory and regulatory requirements. An engineering and design study must carefully consider the action’s short- and long-term safety implications. It must include the level of detail that supports a certified cost estimate. This can vary in detail based on schedules, project complexity, current commodity costs (such as labor and equipment) and other factors. The proposed action must be determined to be cost-effective; the benefits must exceed the costs, including potential impacts to project purposes and other water resource uses.

Multiple offices within the Corps and the Secretary of the Army for Civil Works must review this evaluation. If approved through these steps, the Office of Management and Budget reviews the evaluation for approval by the Administration. If the Administration supports the recommendation for a modification, it may be submitted to Congress for authorization. This is typically accomplished through congressional authorization in a Water Resources Development Act. WRDA bills provide authorization for Corps construction of civil works projects. WRDA was designed to be taken up by Congress every two years but the schedule can be irregular. The last two WRDA reauthorizations passed in 2016 and 2018. However, prior to 2014 it was last reauthorized in 2007.

Learn more about the Water Resources Development Act:

The Corps also may need to seek funding from Congress for any necessary detailed studies and also must develop any documents required to obtain permits and environmental compliance activities.


The process to obtain funding for detailed studies or the actual implementation of authorized modifications, including actions recommended through environmental reviews (such as an environmental impact statement), requires review at multiple levels before submittal to Congress. Funding requests originate in Corps district and division offices and must be approved by Corps Headquarters, the Department of the Army and the Office of Management and Budget. The Corps submits budget priorities and capabilities in June, two years before the budget year for which the funds are requested.

Authorization and dam breaching

Since breaching one or more of the lower Snake River dams in Washington would result in a major structural or operational change or could seriously affect authorized purposes, this action is considered a significant modification requiring congressional authorization. The Corps has not had justification to seek—and currently does not have—the necessary congressional authority through a Water Resources Development Act to breach one or more of the lower Snake River dams

A September 2002 Record of Decision for the Lower Snake River Juvenile Salmon Migration Feasibility Study and Environmental Impact Statement evaluated the technical, environmental and economic effects of several alternatives related to improving juvenile salmon passage through the four lower Snake River dams. One of these alternatives included breaching these dams. After careful analysis, the Corps did not select dam breaching as the preferred alternative. Had the EIS advanced this alternative, it would not have provided authority for this action. The Corps would have to undertake the authorization and funding processes described above. The selected alternative documented in the Record of Decision remains in effect today and actions under this alternative have been underway for many years. 

Current Analysis

The Corps is developing the Columbia River System Operations Environmental Impact Statement, along with the Bonneville Power Administration and the Bureau of Reclamation as co-lead agencies. Using the most current science available, this EIS will determine whether any changes should be made to the coordinated long-term operations, maintenance and configuration of the 14 federal dams in the Columbia River System. The CRSO EIS will evaluate a system that has undergone structural and operational changes since previous NEPA analyses and it will include an alternative that evaluates breaching of the four lower Snake River dams.

If the EIS preferred alternative includes dam breaching, the Corps will use the EIS, in addition to other necessary actions, to seek congressional authorization and appropriations. Until such a time, the Corps must continue to operate, configure and maintain these dams for their authorized purposes.

Additional information is available on the Columbia River System Operations EIS,