THE PROCESS OF SELECTING A WETLAND ASSESSMENT PROCEDURE:
STEPS AND CONSIDERATIONS
Background
Wetland assessment procedures are tools in the trade of wetland science that provide a definitive procedure for identifying, characterizing, or measuring wetland functions and/or social benefits. They are used in a variety of contexts for regulatory, planning, management, and educational purposes. In the 1980s, wetland assessment was simple, as there were only a few procedures to choose from (see summaries in Lonard et al. (1981), U.S. Environmental Protection Agency (1984), World Wildlife Fund 1992)). Wetland scientists were, however, frustrated by the lack of suitable procedures for most situations. Today, there are a variety to choose from, but the process is complicated by the ever-increasing number of procedures, differing approaches, and new terms. This set of menus uses key information on 39 current procedures (Table A).
Each procedure outlines, in varying degrees, the steps to assessing wetland function. Most begin with locating/delineating the wetland and then focus on the application of models (e.g., NH Method (Ammann and Lindley Stone 1991); AREM (Adamus 1993a, 1993b); Descriptive Approach (USCOE 1995); MDE Method (Fugro East, Inc. 1995)). A few describe earlier steps such as defining the assessment objectives or screening for red flags (e.g., Synoptic Approach (Leibowitz et al. 1992); EPW (Bartoldus et al. 1994); HGM Approach (Smith et al. 1995); NEFWPBP (Hicks 1997)). The Regulatory Assessment Method (Kusler 1997) provides guidance on how to conduct a preliminary assessment of wetland functions/values and other factors (e.g., red/yellow flags, natural hazards, alternatives for landowners) before applying an established assessment procedure, but it does not give instructions on how to select a procedure.
The HGM Approach (Smith et al. 1995) takes the lead as technically the most progressive and extensive effort among the wave of recent procedures. It was developed to satisfy the requirements of the 404 Program, but is also intended for use in a wide range of assessment situations. There has been some discussion about scientific and technical issues surrounding the HGM Approach (e.g., Brinson et al. 1997, 1998; Hruby 1997, 1998). Kusler and Niering (1998) take the matter further and pose a series of questions about wetland assessment procedures in general. The underlying cause of these discussions stems from the fact that no one procedure can satisfy the diversity of assessment situations. The same limitations that render a procedure useful for one setting become the basis for questioning the scientific or technical basis in another.
The difficulty in selecting a procedure has led to a need for further guidance. That guidance has not and cannot come from the regulatory agencies for a variety of reasons. As noted before, it is impossible to identify one preferred procedure, because no one method is suitable for all assessment situations. There are numerous procedures and each has been developed for specific purposes. The suitability of a procedure for a project depends upon the assessment objectives, geographic area, wetland type, desired level of detail, availability of applicable models, and other considerations. Additionally, policy favoring any one procedure might be considered an unfair practice. It might also discourage the development of additional, perhaps improved, techniques.
Preparation: Define goals of the assessment
The user must define exactly what he/she wants to achieve and list what the procedure must be able to do to attain these goals. Identify the overall goal(s), then identify specific requirements for the assessment (see Table Step 1a and example in Figure 1). Consider geographic area, habitat types, detail or sensitivity of the procedure, acreage in the measure of function, functions, and comparison of different habitat types.
Users may find that no one procedure can meet a broad range of goals. All procedures have constraints because they are designed for different purposes. For example, the NH Method (Ammann and Lindley Stone 1991) is used to evaluate New Hampshire freshwater wetlands in planning, education, and wetland inventory; but it is not used for detailed impact analysis on individual wetlands. It addresses 15 functional values including wetland wildlife habitat. In contrast, the Habitat Evaluation Procedure (HEP) (USFWS 1980) is used throughout the United States to document the quality and quantity of available wetland/upland habitat for selected fish and wildlife species. HEP can be used for detailed impact analysis and in other planning activities such as compensation analysis. It does not address other function categories with the current published Habitat Suitability Index (HSI) models.
Do not be concerned with the constraints of each procedure at this point. Just focus on the goals. The properties of each procedure are summarized in tables that accompany the following menu choices. Remember to leave options open to the possibility of using more than one procedure. One may be sufficient, but you may have to use or revise a combination of models from different procedures.
To continue with the selection process, enter the system by clicking on Tools on the Information Manager page and choosing Wetland Assessment Procedure. To learn about using the Decision Support Tools - Wetland Assessment Procedure click here.