The U.S. Army Corps of Engineers (USACE) and the U.S. Environmental Protection Agency (EPA) jointly announce the availability of the Interim Draft of the National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams (National OHWM Manual) and are soliciting public comments on this Interim Draft. The Interim Draft of the National OHWM Manual does not imply or represent a change to the definition of “ordinary high water mark” (OHWM) or “Waters of the U.S.” nor does it change existing guidance related to the OHWM (e.g., Regulatory Guidance Letter No. 05-05). Instead, the Interim Draft of the National OHWM Manual provides draft technical guidance for identifying aquatic resources that may be subject to regulatory jurisdiction under Section 404 of the Clean Water Act (CWA) and/or Sections 9 and 10 of the Rivers and Harbors Act of 1899 (RHA), by providing a standard process, uniform datasheets, and unified field procedures to identify and delineate the OHWM of rivers and streams located throughout the Nation. The Interim Draft of the National OHWM Manual was developed by the National Technical Committee for OHWM, which includes experts from Federal agencies and academia. The document provides a scientifically based, rapid framework to support OHWM identification and delineation in a consistent, robust, repeatable, and defensible way.
The OHWM defines the boundaries of aquatic features for a variety of federal, state, and local regulatory purposes. Under the CWA, the OHWM defines the lateral limits of federal jurisdiction for non-tidal waters of the U.S. in the absence of adjacent wetlands. When adjacent wetlands are present, CWA jurisdiction extends beyond the OHWM to the limit of the adjacent wetlands. Under Sections 9 and 10 of the RHA, the OHWM defines the lateral limits of federal jurisdiction for non-tidal navigable waters of the U.S. The National OHWM Manual will help to promote accurate, consistent, and efficient OHWM delineation practices. OHWM delineation can occasionally be challenging due to factors such as spatial and temporal dynamics of inland waters and anthropogenic impacts that can mask or confound field indicators. Use of the National OHWM Manual is intended to result in more timely, consistent, and predictable identification and delineation of the OHWM across the Nation.
The Interim Draft National OHWM Manual, datasheets, and training opportunities are available on the
internet at: https://www.erdc.usace.army.mil/Media/Fact-Sheets/Fact-Sheet-Article-View/Article/486085/ordinary-high-water-mark-ohwm-research-development-and-training/
During the period while the OHWM Manual is an interim draft, OHWM identification and/or delineation for official USACE Regulatory purposes should continue in accordance with the applicable OHWM definition in the Federal regulations, Regulatory Guidance Letter 05-05, and any applicable USACE district policies and/or procedures. However, the public and practitioners are encouraged to test and provide comments on their experience using the Interim Draft National OHWM Manual. Comments and feedback received will be utilized to further refine the Interim Draft National OHWM Manual for clarity, consistency, and technical accuracy.
Comments regarding the following specific topics would be especially useful:
- Indicators that were particularly useful or not useful in identifying the OHWM.
- Regional differences in the applicability of specific field indicators.
- Implementation of the Weight of Evidence approach to assemble, evaluate, and integrate lines of evidence to support OHWM identification and delineation.
- Problem situations encountered and possible approaches for addressing them.
- Additional remote sensing data or techniques which may be utilized to support OHWM identification and delineation.
- Usefulness of the supporting examples to clarify and inform identification of indicators and lines of evidence in the field.
- Usefulness, usability, and clarity of the OHWM datasheet and its accompanying instructions and field procedures.
Comments on the Interim Draft National OHWM Manual should be submitted by email to firstname.lastname@example.org. Written comments may also be provided by mail to Mr. Matt Wilson, U.S. Army Corps of Engineers, Attn: CECW-CO-R, 441 G Street NW, Washington, DC 20314-1000. The one-year comment period ends on December 1, 2023.
A final version of the National OHWM Manual is anticipated to be published during 2024.
For additional information on the research supporting the National OHWM Manual, see: https://www.erdc.usace.army.mil/Media/Fact-Sheets/Fact-Sheet-Article-View/Article/486085/ordinary-high-water-mark-ohwm-research-development-and-training/