ASTM E1983-98

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Designation: E 1983 – 98
Standard Guide for
Assessment of Wetland Functions
This standard is issued under the fixed designation E 1983; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope objectives, and policy of local decision makers. There are
continuous efforts to develop new and improved methods that
1.1 This guide covers assisting wetland managers by pre-
could override any one recommended standard procedure.
scribing a sequence of steps for defining and assessing wetland
1.5 The values stated in inch-pound units are to be regarded
functions. This guide also identifies properties that must be
as the standard. The SI units given in parentheses are for
considered in the selection of a wetland assessment procedure
information only.
to determine whether it will assist in satisfying the require-
1.6 This standard does not purport to address all of the
ments of wetland regulatory programs or produce valid design
safety concerns, if any, associated with its use. It is the
criteria for planned wetlands, or both. This guide can help
responsibility of the user of this standard to establish appro-
wetland managers use existing assessment procedures more
priate safety and health practices and determine the applica-
effectively during the decision-making process. The outcome
bility of regulatory limitations prior to use.
of the assessment is dependent on many factors including the
selected procedure, the sampling design, and assumptions;
2. Terminology
therefore, decisions and assumptions made should be docu-
2.1 Definitions:
mented throughout the process. While this guide is developed
2.1.1 wetland assessment procedure, n—a definitive proce-
to assist in satisfying the requirements of wetland regulatory
dure for identifying, characterizing, or measuring the functions
programs, it can also be used in a variety of planning,
that a wetland performs, or a combination thereof.
management, and educational situations.
2.1.2 wetland functions, n—the physical, chemical, and
1.2 The guide is not intended for use in assigning values to
biological processes or attributes that contribute to the self-
wetland functions in terms of economic (for example, dollars)
maintenance of wetland ecosystems (6) and (7). Wetland
or other value units. However, the information that is gathered
functions result directly from the characteristics of a wetland
while assessing wetland functions may be useful in meeting
ecosystem and the surrounding landscape and their interaction.
this objective when used in conjunction with other information
2 2.1.2.1 Discussion—A wetland function is distinguished
(for example, see Refs (1) and (2)).
from wetland value.Wetland functions are a direct result of the
1.3 This guide applies to assessment procedures designed
characteristics of a wetland and the surrounding landscape.
for application at the ecosystem scale. It does not address the
Examples of functions include the removal of dissolved
less commonly used landscape level models or the use of
substances, cycling of nutrients, maintenance of plant and
wetland assessment procedures for cumulative impacts analy-
animal communities, and short-term storage of surface water.
sis (3-5).
These functions provide benefits, goods, and services which
1.4 Limitations—This guide does not include a standard
may be assigned a value (economic or noneconomic) describ-
wetland assessment procedure or models for assessing func-
ing the relative importance of a wetland function to an
tion. This guide has been written primarily to complement and
individual or group of people. The values of wetlands are
to aid in the selection of current procedures. There are several
estimates, usually subjective, of the worth, merit, quality, or
procedures for quantifying wetland functions and each has
importance of wetland functions (8).
been developed for specific purposes. The suitability of a
2.2 Definitions of Terms Specific to This Standard—Most of
procedure depends on assessment objectives, wetland type,
the following definitions are from Refs (9) and (10).
availability of applicable models given the wetland type and
2.2.1 assessment model, n—a simple model that defines the
relationship between ecosystem and landscape scale variables
This specification is under the jurisdiction of ASTM Committee E50 on and functional capacity of a wetland; it is used to derive a
EnvironmentalAssessment and is the direct responsibility of Subcommittee E50.02
measure of functional capacity (that is, the functional capacity
on Commercial Real Estate Transactions.
index).
Current edition approved Nov. 10, 1998. Published February 1999.
Theboldfacenumbersgiveninparenthesisrefertoalistofreferencesattheend
of the text.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1983–98
2.2.2 conceptual design, n—a design that provides a brief techniques in a given subject area and to provide information
description of the planned wetland through drawings and text from which subsequent evaluation and standardization can be
derived.
which confirms feasibility and facilitates early review by
decision makers. 2.3.2 practice—a definitive procedure for performing one
or more specific operations or functions that does not produce
2.2.3 functionalcapacity,n—themagnitudeorrateatwhich
a test result.
a wetland performs a function. Functional capacity is dictated
2.3.2.1 Discussion—A practice is not a downgraded test
by the characteristics of the wetland ecosystem and the
method.Examplesofpracticesincludeproceduresofinterlabo-
surrounding landscape, and the interaction between the two.
ratory testing programs or other statistical procedures; for
2.2.4 functional capacity index (FCI), n—an index of the
writing statement on sampling or precision and accuracy; and
capacity of a wetland to perform a function relative to other
for selection, preparation, application, inspection, and neces-
wetlands from a defined region or wetland class, or both.
sary precautions for the use, disposal, installation, and main-
Functional capacity indices are by definition normally scaled
tenance, and operation of testing equipment.
from 0.0 to 1.0. An index of 1.0 indicates that a wetland
2.3.3 standard—as used in ASTM, a document that has
performs a function at maximum functional capacity.An index
beendevelopedandestablishedwithintheconsensusprinciples
of 0.0 indicates the wetland does not perform the function.
of the Society and that meets the approval requirements of
2.2.5 functional capacity units (FCs), n—a measure of the
ASTM procedures and regulations.
capacity of a wetland to perform a function that links func-
2.3.3.1 Discussion—The term “standard” serves in ASTM
tional capacity with area (FC = FCI 3 size of wetland area).
as an adjective in the title of documents such as test methods
2.2.6 planned wetland, n—designoranimplementeddesign or specifications, to connote specified consensus and approval.
for a constructed, created, restored, or enhanced wetland. The various types of standard documents are based on the
needs and usages as prescribed by the technical committees of
2.2.7 variable, n—an attribute or characteristic of a wetland
the Society.
ecosystem or the surrounding landscape that influences the
capacityofawetlandtoperformafunction;usedinassessment
3. Summary of Guide
models to derive a measure of functional capacity (that is, the
3.1 This guide is summarized in Table 1, that shows the
functional capacity index). Variables may be described by
steps in defining and assessing wetland functions and the
directmeasuresorindicators.Adirectmeasureisaquantitative
sections of this guide that apply.
measure of an assessment model variable. An indicator is an
3.2 The remainder of this guide identifies properties to
observable characteristic that corresponds to identifiable vari-
considerwhenselectingaprocedureormodels,andasummary
able conditions in a wetland or the surrounding landscape.
of existing procedures (see Section 7).Appendix X1 describes
2.2.8 wetland assessment area (WAA), n—the wetland area
the specific application of wetland assessment to planned
being assessed. In regulatory situations, the WAA will usually
wetlands.
be jurisdictional wetlands confined to the area of direct or
indirect impact or both.
4. Significance and Use
2.2.9 wetland classification, n—the grouping of wetlands
4.1 Wetland managers may be aware of wetland assessment
into different categories based on specific criteria (that is,
procedures, but not use them as effectively as possible for a
vegetation type, hydrology, geomorphology) for the purpose of
variety of reasons. There is no one universally accepted
inventory, assessment, and management.
procedure; therefore, time is often lost to identifying and
2.2.9.1 Discussion—There are several wetland classifica-
agreeing upon a suitable approach. The absence of guidance
tion schemes including the Classification of Wetlands and
Deepwater Habitats of the United States (11) and the hydro-
TABLE 1 Suggested Steps in the Assessment of Wetland
geomorphic classification (12). Each has been prepared for
Functions
different purposes. One or more of these classifications may be
Steps Rules
used in the process of assessing wetland functions.
Characterization Phase: 6.2
Define objectives of the assessment 6.2.1
2.3 Additional Terminology—The following definitions and
Select functions 6.2.2
discussions, taken directly from the publication “Form and
Describe the project area 6.2.4
Style for ASTM Standards,” shall be included in full in every
Identify wetland assessment area(s) 6.2.6
Screen for red flags 6.2.7
standard guide or practice produced and passed by Committee
E-50 or any of its technical subcommittees; approvedApril 16,
Identification of Assessment Approach: 6.3
Identify, modify, or develop assessment models 6.3.1
1997.
Select the units of measure 6.3.2
2.3.1 guide—a series of options or instructions that do not
recommend a specific course of action. Assessment Phase 6.4
2.3.1.1 Discussion—Whereas a practice prescribes a gen-
Analysis Phase: 6.5
eral usage principle, a guide only suggest an approach. The
Types of comparisons 6.5.1
Other criteria to consider when comparing wetland 6.5.5
purpose of a guide is to offer guidance, based on a consensus
assessment areas
of viewpoints, but not to establish a fixed procedure.Aguide is
intended to increase the awareness of the user to available
E1983–98
describing the sequence of steps to assessing wetland functions or creation, or enhancement or preservation of an existing
causes confusion and delays the decision-making process. wetland to compensate for wetland impacts. Several ap-
Only recently has guidance been published by the U.S. Army proaches to mitigation may be considered and compared at this
Corps of Engineers (9). time including in-kind, out-of-kind, on-site, off-site, and miti-
4.1.1 This guide shows the person(s) performing an assess- gation banking. Whichever option is chosen, the mitigation
ment the steps to assess wetland functions. This guide also project is later assessed (during Step 7) to determine whether
provides a summary of the variety of procedural options for the function-based objectives have been met in the conceptual
measuringfunction,andincludesalistofpropertiestoconsider plans or the completed planned wetland, or both.
when selecting an appropriate procedure.
4.3.2.1 Many states and local governments have adopted
4.2 Situations Requiring Assessment of Wetland
regulatory wetland statutes which set forth procedures for
Functions—While this guide is developed to assist in satisfy-
permit applications similar to the federal Section 404 program
ing the requirements of wetland regulatory programs, it can
(see review in Ref (13)). The need to assess wetland functions
also be used in a variety of planning, management, and
is similar, but specific requirements may differ depending upon
educational situations.
the individual state program.
4.3 Rapid Assessment for Section 404 Permitting—Section
4.3.2.2 Mitigation Banking—One option for meeting any
404 of the Clean WaterAct (33 U.S.C. 1344) directs the U.S.
compensatory mitigation requirements is to use a mitigation
Army Corps of Engineers, in cooperation with the U.S.
bank. Mitigation banking is wetland restoration, creation, or
Environmental Protection Agency (EPA), to administer a
enhancement undertaken expressly for the purpose of provid-
programforpermittingandregulatingthedischargeofdredged
ing compensation credits for wetland losses from future
or fill materials in waters of the United States, including
developmentactivities.Awetlandassessmentprocedurecanbe
wetlands. A permit application undergoes a public interest
used to asses the loss of functions at an impact site, to assess
review that includes an assessment of the impacts the proposed
functions to date at the mitigation bank, and to determine the
project will have on wetland functions.
number of credits (expressed in terms of functional capacity or
4.3.1 An assessment may be performed during one or more
acreage, or both) that must be purchased at the mitigation bank
of the following steps of the review sequence that are pre-
to compensate for the impacts.
scribed in the U.S. EPA 404(b)(1) Guidelines (40 CFR Part
4.3.3 Other Applications—There are a variety of non-
230)
regulatory situations where there is a need to assess wetland
4.3.1.1 Step 1—Determine whether the proposed project is
function. A rapid wetland assessment procedure that is appro-
water dependent.
priatefortheSection404 programcouldbeused,buttimeand
4.3.1.2 Step 2—Determine whether practicable alternatives
resources may also allow for more detailed analyses.
exist for the proposed project.
4.3.3.1 Advanced Identification (ADID)—Advanced Identi-
4.3.1.3 Step 3—Identify the potential impacts of the pro-
fication is a planning process authorized by Section 404
posed project on wetland functions in terms of project specific
regulations (40 CFR Part 230.80) that allows the U.S. EPA, in
and cumulative effects.
cooperation with the U.S. Army Corps of Engineers and state
4.3.1.4 Step 4—Identify how potential project impacts can
and local agencies, to collect information on the functions of
be avoided or minimized in terms of project-specific and
the wetlands in selected study areas. The agencies evaluate the
cumulative effects.
information to determine which wetlands in the ADID study
4.3.1.5 Step 5—Determine appropriate com
...