The ordinary high water mark (OHWM) defines the boundaries of aquatic features for a variety of federal, state, and local regulatory purposes. Under the Clean Water Act, the OHWM defines the lateral limits of federal jurisdiction for non-tidal waters of the U.S. in the absence of adjacent wetlands (including Section 404, which regulates the discharge of dredge and fill material into waters of the U.S.). Additionally, under Sections 9 and 10 of the Rivers and Harbors Act of 1899, the OHWM defines the lateral limits of federal jurisdiction for non-tidal traditional navigable waters of the U.S. Accurate, consistent, and efficient OHWM delineation practices are thus essential to proper and effective implementation of these laws and regulations by the U.S. Army Corps of Engineers Regulatory Program and other agencies. However, OHWM delineation can be challenging in light of the spatial and temporal dynamics of inland waters and the various anthropogenic impacts that compound this complexity.
ERDC works with the Corps Regulatory Program, other federal agencies, and the academic community to develop regional and national OHWM delineation standards and procedures and to improve OHWM delineation practices across the country. Research scientists test and validate the field indicators and methods used in OHWM delineations and explore new tools, techniques, and resources to improve the accuracy, consistency, and efficiency of OHWM delineation practices. These efforts have resulted in OHWM delineation manuals and other technical resources that support both the Corps Regulatory Program and the regulated public. This work is largely funded through the Corps Wetlands Regulatory Assistance Program (WRAP).
Regional Delineation Manuals
Western Mountains, Valleys, and Coast: A Guide to Ordinary High Water Mark (OHWM) Delineation for Non-perennial Streams in the Western Mountains, Valleys, and Coast Region of the United States (Mersel and Lichvar 2014)
Arid West: A Field Guide to the Identification of the Ordinary High Water Mark (OHWM) in the Arid West Region of the Western United States (Lichvar and McColley 2008)
Supporting Research and Technical Reports
The Benefits and Limitations of Hydraulic Modeling for Ordinary High Water Mark Delineation (Gartner et al. 2016)
Hydrologic Modeling and Flood Frequency Analysis for Ordinary High Water Mark Delineation (Gartner et al. 2016)
Integrating Hydrologic Modeling, Hydraulic Modeling, and Field Data for Ordinary High Water Mark Delineation (Gartner et al. 2016)
Occurrence and Distribution of Ordinary High Water Mark (OHWM) Indicators in Non-perennial Streams in the Western Mountains, Valleys, and Coast Region of the United States (Mersel et al. 2014)
A Review of Land and Stream Classifications in Support of Developing a National Ordinary High Water Mark Classification (Mersel et al. 2014)
Channel Classification across Arid West Landscapes in Support of OHW Delineation (Lefebvre et al. 2013)
Survey of OHWM Indicator Distribution Patterns across Arid West Landscapes (Lefebvre et al. 2013)
Ordinary High Flows and the Stage-Discharge Relationship in the Arid West Region (Curtis et al. 2011)
Vegetation and Channel Morphology Responses to Ordinary High Water Mark Discharge Events in Arid West Stream Channels (Lichvar et al. 2009)
Review and Synopsis of Natural and Human Controls on Fluvial Channel Processes in the Arid West (Field and Lichvar 2007)
Distribution of Ordinary High Water Mark (OHWM) Indicators and Their Reliability in Identifying the Limits of "Waters of the United States" in Arid Southwestern Channels (Lichvar et al. 2006)
Regulatory Guidance Letter: Ordinary High Water Mark Identification (USACE 2005)
Review of Ordinary High Water Mark Indicators for Delineating Arid Streams in the Southwestern United States (Lichvar and Wakeley 2004)
Other Resources
OHWM Delineation Datasheet
Contact
**We welcome any significant data or information that may be pertinent to OHWM indicators and delineation methods and that may help to advance our research on this topic. Please submit any such information to contact below.
Matthew.K.Mersel.civ@mail.mil | 603-646-4873