The U.S. Army Corps of Engineers designed and constructed flood reduction projects using appropriate standards at the time that the projects were constructed. Design standards have evolved over the past 100 years. One area of current design concern is vegetation near, or on, levees. The existence of woody vegetation on or near levees may reduce the levee-performance and thereby increase the risk of loss of life and property.
The Corps' variance request procedure published in the Federal Register (February 17, 2012) provides substantive and procedural standards to ensure full consideration of environmental issues and alternatives, and an opportunity for the public to participate in evaluating environmental factors and alternatives. The effort undertaken by the public sponsor in submitting a variance request through the Corps' variance procedure is considered the opportunity for the public to participate.
The Corps recognizes that unusual circumstances may justify some degree of exception with the best practices that are now recognized for levee maintenance and operation and therefore has made provision for a process to request a variance from our Operations and Maintenance requirements. The variance procedure has been published in the Federal Register (see link below) and is currently being used to accept and review vegetation variances requests in its draft form.
The vegetation variance purpose is not to generate paperwork but to foster full consideration of the merits of a variance request and protect public safety. In seeking the variance the project sponsor is asking for an exception from internationally recognized maintenance operations and procedures that have been developed to be as protective as possible of human life and property. No variance will be approved that might directly lead to Levee non-performance and loss of life.
The vegetation variance request documents must concentrate on all the issues that are truly significant to the action in question. The documents must be of high quality. Accurate scientific analysis, well founded engineering analysis, expert agency comments and since there may be an increase in risk should the variance be approved, public review are essential to implementing the variance. The variance request must demonstrate that any increased risk is justified by the specific cultural or environmental benefits outlined in the variance provisions.
Should the Corps deny the variance, the action of removing the non-compliant vegetation as part of the maintenance activities is considered a categorical exclusion under the National Environmental Policy Act (NEPA) Appendix B to Part 651Section II (g) and if “regular maintenance”, can be implemented without a National Environmental Policy Act “Environmental Impact Statement”. The Sponsor is requested to contact the district in writing for further information on the regulations that may apply as applicability of regulations are site condition specific. Be aware that there may be other issues that need permit coordination such as wetland and historic preservation.
Vegetation outside of the Project’s existing real estate interest is of concern to the Corps as it may affect levee performance; however, for vegetation lying outside of the Project’s existing real estate interest, the Corps recognizes that it is beyond the control of either the Corps or the sponsor to remove. The Corps' Engineering Technical Letter ETL 1110-2-571 dated April 10, 2009 (vegetation Engineering Technical Letter) specifically address vegetation along levees and should be referenced in both operation of the levee and the variance application, if sought.
Additional information regarding vegetation can be found on the links below: