Jump to main content or area navigation.

Contact Us

Water: Wetlands

Fact Sheet: Methods for Evaluating Wetland Condition

December 2001

The U.S. Environmental Protection Agency (EPA) is publishing a series of modules, collectively titled "Methods for Evaluating Wetland Condition," to help states and tribes build their capacity to monitor and assess the biological and nutrient conditions of wetlands. Few states monitor wetland health or have fully incorporated wetlands into their water quality programs. These modules will provide information to state and tribal water quality managers on how to conduct ecological assessments of wetland health. The modules focus on biological and nutrient assessment techniques and can be used for the development of biological and nutrient criteria for wetlands. These modules also will serve as a basis for developing future EPA guidance for wetlands water quality.


Wetlands are waters of the U.S. according to the Clean Water Act (CWA) and are included in state and tribal water quality standards as "waters of the State," although few states or tribes routinely monitor them. In the 1998 Water Quality Report to Congress, states and tribes cumulatively reported on the designated use support of 4% of the Nation's wetlands; only three states reported using wetland monitoring data as a basis for determining attainment of water quality standards.

Few states or tribes have fully incorporated wetlands into their water quality programs, and even fewer have developed designated uses and criteria specifically for wetlands. As a result, many designated uses and criteria applied to wetlands are not ecologically appropriate. Currently, 10 states and tribes are working on biological assessment methods at some level; most states/tribes have not yet focused on wetland nutrient assessments. States and tribes want to monitor wetlands. However, they do not have the resources or knowledge base to effectively monitor and assess wetland systems.

Why is EPA publishing these wetland modules?

EPA is publishing these modules to help states and tribes and others who want to build their capacity to monitor wetland systems. EPA also intends to use this material to develop more detailed guidance on these topics.

What are wetland biological assessments?

Wetland biological assessments are an evaluation of the biological condition of a wetland. They are based on surveys of the diversity, composition, and functional organization of the community of resident wetland biota (e.g., macroinvertebrates, plants, amphibians, birds, amphibians, algae). Bioassessments often include the collection of some physical and chemical data.

Top of Page

Why do biological assessments?

Biological assessments are a powerful tool for evaluating the health of wetlands. The information they provide can lead to the development of biological criteria and ecologically-based designated uses for wetlands. In addition, biological assessments can be used to help evaluate the performance of restoration, best management practices (e.g., buffer strips), and other conservation actions.

How do we assess the effects of nutrients on wetlands?

The effects of nutrients on a wetland are assessed using ecological and biogeochemical parameters including landscape characterization, nutrient load estimation, hydrology, and analyses of soil, algae, vegetation, and water quality.

Why assess nutrient effects?

States and tribes identified excessive nutrient enrichment as one of the leading sources of water quality degradation in the U.S. The 1998 National Strategy for the Development of Regional Nutrient Criteria describes EPA's approach in developing nutrient criteria for all waterbody types including wetlands. The effects of nutrient enrichment on most wetlands are largely undocumented. Increased monitoring by states and tribes will help define nutrient effects and will provide data for developing wetland nutrient criteria.

Top of Page

What topics do the modules address?

The modules being released include: an introductory, administrative, and study design modules, and modules that provide guidance on the following topics: wetland plants, macroinvertebrates, algae, amphibians, birds, nutrient enrichment, classification, land-use characterization and volunteer monitoring. Additional modules will be added to this series. Biological and nutrient wetland assessments are relatively young fields experiencing rapid development, and this series of modules will serve to document the accumulating body of information. You can find a list of the modules available at the web site given below.

Who wrote them?

Government, private and academic members of the EPA Wetland Nutrient Criteria and the Biological Assessment of Wetlands Workgroups wrote these modules under the guidance of the EPA's Office of Science and Technology and Office of Wetlands, Oceans and Watersheds. All modules were reviewed by external experts.

How do I get copies of these modules?

You can get copies of the "Methods for Evaluating Wetland Condition" modules from the EPA National Service Center for Environmental Publications (NSCEP) by phone at (513) 489-8190 or toll-free (800) 490-9198, or by e-mail to:ncepiwo@one.net. To get them by conventional mail, write to NSCEP at 11029 Kenwood Road, Cincinnati, OH 45242. You can also find the document at these Internet addresses:

Top of Page

Jump to main content.