Primary purpose
To identify and display wetland functions and values for highway and other projects reviewed under the 404 Regulatory Program.
Expertise needed
Interdisciplinary team of professionals from the U.S Army Corps of Engineers (COE), State, other federal agencies, and the applicant.
Applicable habitat types
All wetland types within boundaries of COE New England District.
Categories assessed
Thirteen functions and values are addressed: ground water recharge/discharge; floodflow alteration; fish and shellfish habitat; sediment/toxicant/pathogen retention; nutrient removal/retention/transformation; production export; sediment/shoreline stabilization; wildlife habitat; recreation; educational/scientific value; uniqueness/heritage; visual quality/aesthetics; and threatened or endangered species habitat.
Procedure
Users visit a wetland area and use best professional judgement to prepare (a) a brief qualitative description of the physical characteristics of the wetland, (b) a list of functions and values exhibited, and (c) the rationale for the conclusions. There are no models.
Key Terminology
Function: self-sustaining properties of a wetland ecosystem that exists in the absence of society.
Value: benefits that derive from either one or more functions and the physical characteristics associated with a wetland.
Output
Indication of occurrence of individual functions/values at a site.
Estimated time to assess 1 acre site
2 hours: Complete top portion of form (step1), evaluate functions and values (step 2), and record results (step 3).
Comparison of habitat types
Can directly compare wetlands within geographic boundaries of the COE New England Division.
Use as guide to design
The Descriptive Approach should not be used as a guide to design. It is not the intended purpose for the procedure; therefore, it contains properties that limit its application for this purpose. For example, Descriptive Approach uses opportunity variables (considerations), but does not set upper limits on those opportunities that could potentially reduce function (e.g., opportunity for nutrient attenuation is a preferred condition for the nutrient removal/retention/transformation function). In some circumstances, a wetland may not have the capacity to remove all nutrient input. An upper limit on the opportunity must be defined to insure that the existing or planned wetland can predictably have the capacity to provide a function. Also, the Descriptive Approach does not provide validated threshold values for many variables. Another aspect to consider is whether the model can provide explicit design criteria. The design criteria for this function would be not be explicit (e.g., design for vegetation diversity/abundance sufficient to utilize nutrients). A high degree of subjective judgement is used to note occurrence of a function based on one or all of the listed variables. Unless the rationale is documented, it would be difficult to determine which variables or other information should be incorporated into the design to maximize function.
Contact person
Christine Godfrey, U.S. Army Corps of Engineers, New England District,
Attn: NAE-CO-R, 696 Virginia Road, Concord, MA 01742-2751
phone: (978) 318-8335; fax: (978) 318-8303; e-mail: christine.a.godfrey@usace.army.mil
Related procedures
None.
Extent of use/field testing
The Descriptive Approach has been used on a variety of projects including highway and commercial applications. Most of the projects had impacts greater than one acre, but a few were small (e.g., 5,000 ft2 to 1 acre). The Descriptive Approach has been used on an estimated 20-30 projects during the past two years.
Proposed future revisions
None.
Key Reference
U.S. Army Corps of Engineers. 1995. The Highway Methodology Workbook Supplement. Wetland Functions and Values: A Descriptive Approach. U.S. Army Corps of Engineers, New England Division. NENEP-360-1-30a. 32 pp.