29 Sep 2025

Planning-Level Wetland Delineation of Fee-Owned and Trust-Held Properties of the Little Traverse Bay Band of Odawa Indians

Abstract: A planning-level wetland delineation is an important visualization tool for identifying the location and type of wetlands on the landscape, prioritizing areas for conservation and restoration practices, performing alternative analysis, and informing design and development of infrastructure needs. This study used a combination of off-site data analysis and field data collection to identify the location and extent of wetlands on 1,428 acres of fee-owned and trust-held properties of the Little Traverse Bay Band of Odawa Indians (LTBB). The study found that a wide variety of wetlands occur across approximately 313.6 acres, including 65 acres of wetland-nonwetland mosaic features. These wetlands benefit local communities by providing flood risk reduction, habitat for a wide array of species, and improved water quality. Opportunities to increase wetland functions through management activities, including restoration, were identified. This wetland delineation was conducted under the Planning Assistance to States Program, which provides technical assistance to states, tribal communities, and local governments and was administered via an agreement between the US Army Corps of Engineers–Detroit District and the LTBB. This approach has the potential to provide similar information to other tribal groups interested in identifying and delineating wetlands to improve the management of valuable natural resources.

12 Sep 2025

Identifying Hydric Soils Using α,α′-Dipyridyl Dye

Purpose: The application of α,α′-dipyridyl dye (pronounced alpha, alpha di-peeri-dill) provides a reliable and defensible mechanism for documenting the presence of reduced iron in support of hydric soil identification and wetland delineation activities. The α,α′-dipyridyl dye has proven particularly useful for identifying hydric soils in naturally problematic, altered, and disturbed soils. The proper application of paper test strips embedded with α,α′-dipyridyl dye further promotes the use of this technique to improve wetland delineation and management. This technical note summarizes the state of the science related to α,α′-dipyridyl dye and provides practitioner recommendations for applying, documenting, and interpreting α,α′-dipyridyl dye in hydric soil and wetland investigations.

9 Jan 2025

National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams: Final Version

Abstract: The ordinary high water mark (OHWM) defines the lateral extent of non-tidal aquatic features in the absence of adjacent wetlands in the United States. The federal regulatory definition of the OHWM, 33 CFR 328.3(c)(4), states the OHWM is “that line on the shore established by the fluctuations of water and indicated by physical characteristics such as [a] clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas.” This is the first manual to present a methodology for nationwide identification and delineation of the OHWM. A two-page data sheet and field procedure outline a weight-of-evidence (WOE) methodology to organize and evaluate observations at stream sites. This manual presents a consistent, science-based method for delineating the OHWM in streams. It also describes regional differences and challenges in identifying the OHWM at sites disturbed by human-induced or natural changes and illustrates how to use remote data to structure field inquiries and interpret field evidence using the principles of fluvial science. The manual demonstrates that, in many landscape settings, the OHWM may be located near the bankfull elevation.

7 Feb 2023

Remote Sensing Tools to Support Ordinary High Water Mark Delineation

Abstract: This document is a technical note (TN) that describes existing and recently developed tools to support ordinary high water mark (OHWM) identification and delineation. It also presents a case study to demonstrate how utilizing the tools provide supporting lines of evidence in OHWM delineations.