The Hydrogeomorphic Wetland Report


The Colorado Geological Survey, Colorado School of Mines, and Colorado State University recently completed a two-year study of five wetlands in Colorado. The project was assisted with funding from the U.S. Environmental Protection Agency’s State Wetlands Grant program which is coordinated by the Colorado Department of Natural Resources. Characterization and Functional Assessment of Reference Wetlands in Colorado is the title of the project’s report (388 pages plus appended material).

The purpose of the study was to offer a starting point from which to create guidebooks for wetland management from a regional perspective. The first objective was to compile and assess information about wetlands management by county and municipal governments across Colorado. Some 240 questionnaires were sent out and 32 counties and 52 municipalities responded. Most of those responding do not have wetlands management programs. A variety of management problems were reported and over 85% of respondents expressed interest in having a rapid, inexpensive, functional assessment methodology for wetlands as well as having other technical assistance made available to local government. Development and application of an assessment technique is the focus of the report.

Five reference wetland study sites were identified in the Colorado, Yampa, and Green River basins. These sites are located in Summit, Grand, and Moffat counties and selected to reflect a variety of examples by altitude, wetland type, and nature of human-caused impacts. Each site was then described and monitored for the purpose of identifying useful qualitative and quantitative indicators of wetland functions. The reference sites are to become benchmarks against which other wetlands can be compared.

Wetlands were assessed using the hydrogeomorphic approach (HGM). This approach is being developed by the U.S. Army Corps of Engineers and it is focused on three types of information about a site: (1) the geomorphic setting; (2) water source and transport; and (3) the hydrodynamics. Vegetation is not a major classification and assessment feature. Wetland functions are assumed to be largely dependent on physical and chemical factors and the condition of the ecosystem and maintenance of the wetlands is assumed to reflect these factors. The report offers a valuable resource in illustrating how to apply the assessment techniques and how to interpret results. The focus of field work is on hydrochemical, geochemical, sediment retention, and carbon storage and export variables.

The intent of HGM is to allow a variety of wetland types to be grouped by characteristics which correspond to functions critical to water supply and quality in locations such as the Rocky Mountain region. In turn this approach can enable better management direction for the valuation of site-specific wetland functions and for the design of any needed mitigation and restoration requirements.

A limited number of copies of the report are available on a loan-out basis. The principal investigators were David Cooper (CSU), John Emerick and Ken Kolm (CSM) and David Noe (CGS) who was Project Manager. Reviews and comments on the report would be appreciated. Contact David Noe at             303-866-2432       to borrow a copy. An editorial comment — The thoroughness and detailed explanation of methodology and interpretation in the report will make it a benchmark for wetlands assessment.