Archaeological Impact Assessment Guidelines
3.0 Archaeological Impact Assessment and Review
Process
Part 3 of 4
An archaeological impact assessment will be required
where potential impacts to archaeological resources are
identified in the overview study. The impact assessment
is designed to gain the fullest possible understanding
of archaeological resources which would be affected by
the project.
The primary objectives of the impact assessment are
to:
- identify and evaluate archaeological
resources within the project area;
- identify and assess all impacts on
archaeological resources which might result from the
project; and
- recommend viable alternatives for
managing unavoidable adverse impacts including a
preliminary program for;
- implementing and scheduling
impact management actions and, where necessary,
- conducting surveillance and/or
monitoring
Information provided by the impact assessment is
intended to assist the proponent in choosing a suitable
approach to designing, planning and implementing the
proposed project while giving consideration to
archaeological resources. In the course of fulfilling
these basic objectives, it is often possible to conduct
problem-oriented research aimed at enhancing scientific
knowledge and public appreciation of British Columbia's
archaeological resources. The effective integration of
management and research is a desirable quality of impact
assessment studies and should be recognized as an
integral part of such studies.
Two basic research activities are associated with the
impact assessment level of study: (1) inventory, and (2)
impact identification and assessment. Due to uncertainty
as to the number or types of archaeological sites which
might be encountered during the inventory stage, it is
often preferable to separate that stage from the impact
identification and assessment stage.
Inventory studies involve the in-field survey and
recording of archaeological resources within a proposed
development area. The nature and scope of this type of
study is defined primarily by the results of the
overview study. In the case of site-specific
developments, direct implementation of an inventory
study may preclude the need for an overview.
There are a number of different methodological
approaches to conducting inventory studies. Therefore,
the proponent, in collaboration with an archaeological
consultant, must develop an inventory plan for review
and approval by the Branch prior to implementation.
3.5.1.1 Site Surveying
Site surveying is the process by which archaeological
sites are located and identified on the ground.
Archaeological site surveys often involve both surface
inspection and subsurface testing.
A systematic surface inspection involves a foot traverse
along pre-defined linear transects which are spaced at
systematic intervals across the survey area. This
approach is designed to achieve representative areal
coverage. Alternatively, an archaeological site survey
may involve a non-systematic or random walk across the
survey area. Subsurface testing is an integral part of
archaeological site survey. The purpose of subsurface
testing, commonly called "shovel testing", is to:
- assist in the location of archaeological sites which
are buried or obscured from the surveyor's view, and
- help determine the horizontal and vertical
dimensions and internal structure of a site.
In this respect, subsurface testing should not be
confused with evaluative testing (section 3.5.2.1),
which is a considerably more intensive method of
assessing site significance.
Once a site is located, subsurface testing is conducted
to record horizontal extent, depth of the cultural
matrix, and degree of internal stratification. Because
subsurface testing, like any form of site excavation, is
destructive it should be conducted only when necessary
and in moderation.
Subsurface testing is usually accomplished by shovel,
although augers and core samplers are also used where
conditions are suitable. Shovel test units averaging 40 square cm are generally appropriate, and are excavated
to a sterile stratum (i.e. C Horizon, glacial till,
etc.). Depending on the site survey strategy, subsurface
testing is conducted systematically or randomly across
the survey area. Other considerations such as test unit
location, frequency, depth and interval spacing will
also depend on the survey design as well as various
biophysical factors. All test units placed on a site
must be accurately recorded and mapped.
3.5.1.2 Survey Sampling
Site survey involves the complete or partial inspection
of a proposed project area for the purpose of locating
archaeological sites. Since there are many possible
approaches to field survey, it is important to consider
the biophysical conditions and archaeological site
potential of the survey area in designing the survey
strategy.
Ideally, the archaeological site inventory should be
based on intensive survey of every portion of the impact
area, as maximum areal coverage will provide the most
comprehensive understanding of archaeological resource
density and distribution. However, in many cases the
size of the project area may render a complete survey
impractical because of time and cost considerations.
In some situations it may be practical to intensively
survey only a sample of the entire project area. Sample
selection is approached systematically, based on
accepted statistical sampling procedures, or
judgementally, relying primarily on subjective criteria.
3.5.1.3 Systematic Survey Sampling
A systematic sample survey is designed to locate a
representative sample of archaeological resources within
the project area. A statistically valid sample will
allow predictions to be made regarding total resource
density, distribution and variability. In systematic
sample surveys it may be necessary to exempt certain
areas from intensive inspection owing to excessive
slope, water bodies, landslides, land ownership, land
use or other factors. These areas must be explicitly
defined. Areas characterized by an absence of road
access or dense vegetation should not be exempted.
The proponent is encouraged to seek professional
consultation to ensure that the sampling methods
selected for archaeological site survey are both
appropriate and accurately applied. In this regard,
survey sampling methods applied under similar
environmental and project conditions should be
consulted.
3.5.1.4 Judgemental Survey Sampling
Under certain circumstances, it is appropriate to survey
a sample of the project area based entirely on
professional judgement regarding the location of sites.
Only those areas which can reasonably be expected to
contain archaeological sites are surveyed.
However, a sufficient understanding of the cultural and
biophysical factors which influenced or accounted for
the distribution of these sites over the landscape is
essential. Careful consideration must be given to
ethnographic patterns of settlement, land use and
resource exploitation; the kinds and distribution of
aboriginal food sources; and restrictions on site
location imposed by physical terrain, climatic regimes,
soil chemistry or other factors. A judgemental sample
survey is not desirable if statistically valid estimates
of total archaeological resource density and variability
are required.
3.5.1.5 Site Recording
Site survey includes the complete documentation of each
identified site. All archaeological sites in British Columbia are recorded on standard site inventory forms
available from the Branch.
The Archaeological Site Inventory Form Guide must be
consulted when recording archaeological sites. This
manual identifies the kinds of information to record and
the procedures to follow in completing site inventory
forms. Site forms should include a description of site
characteristics, along with a map of the site drawn to
scale. The map should illustrate the arrangement of site
features, as well as the location of the site relative
to the nearest recognizable and permanent landmark.
Since these sites are often situated in remote areas,
the map must be drawn in sufficient detail to allow easy
relocation in the field. Legal descriptions should be
provided wherever possible.
Site recording should also include a thorough
description of all observed cultural materials. It is
recommended that a representative selection of
diagnostic artifacts or features be drawn to scale or
photographed in situ. Drawings and photographs should be
included with the inventory form.
Once completed, site inventory forms must be forwarded
to the Branch. The Branch will assign a "Borden"
identification number to each site and subsequently
notify the proponent and/or his archaeological
consultant as to which numbers have been assigned. Since
Borden numbers can only be assigned by Branch staff,
temporary site numbers must be used in the field.
Impact assessment studies are only required where
conflicts have been identified between archaeological
resources and a proposed development. These studies
require an evaluation of the archaeological resource to
be impacted, as well as an assessment of project
impacts. The purpose of the assessment is to provide
recommendations as to the most appropriate manner in
which the resource may be managed in light of the
identified impacts. Management options may include
alteration of proposed development plans to avoid
resource impact, mitigative studies directed at
retrieving resource values prior to impact, or
compensation for the unavoidable loss of resource
values.
There are several methodological approaches that can be
utilized in conducting an impact assessment. Therefore,
the proponent's archaeological consultant must develop
an impact assessment proposal for review and approval by
the Branch prior to implementation.
It is especially important to utilize specialists at
this stage of assessment. The evaluation of any
archaeological resource should be performed by
professionally qualified individuals. The involvement of
researchers with varied expertise throughout this stage
will help ensure that potentially significant data are
not inadvertently overlooked.
3.5.2.1 Site Evaluation
Techniques utilized in evaluating the significance of an
archaeological site include systematic surface
collecting and evaluative testing. Systematic surface
collection is employed wherever archaeological remains
are evident on the ground surface. However, where these
sites contain buried deposits, some degree of evaluative
testing is also required.
Surface collecting involves:
- placing an appropriate grid over the site area or
some portion thereof;
- mapping, measuring, and recording all cultural items
and other relevant materials observed within the grid
system; and
- collecting and cataloguing recorded materials.
Systematic surface collection from archaeological sites
should be limited, insofar as possible, to a
representative sample of materials. Unless a site is
exceptionally small and limited to the surface, no
attempt should be made at this stage to collect all or
even a major portion of the materials. Intensive surface
collecting should be reserved for full scale data
recovery if mitigative studies are required. Site
significance is determined following an analysis of the
surface collected and/or excavated materials.
Evaluative testing or "test excavation" is appropriate
at archaeological sites containing buried cultural
materials. Evaluative testing implies "controlled"
excavation of a portion of such sites using established
data recovery techniques. The objective is to gain a
sufficient impression of the content and structure of a
site so that a reliable evaluation of significance can
be made. Evaluative testing will also provide necessary
information for estimating the cost of full-scale
excavation should this activity be necessary.
Evaluative testing involves:
- systematic excavation of one or more units by stratigraphic or arbitrary levels;
- mapping, measuring, and recording the horizontal and
vertical provenience of all cultural items or other
relevant materials observed within each excavation unit;
and
- recovery and cataloguing of all cultural materials.
Profile drawings of the stratigraphy and features
exposed in the walls of excavation units should also be
prepared where appropriate. Site significance is based
on the subsequent analysis and interpretation of
recovered materials and the context in which they were
found.
Evaluative testing should not be interpreted as a
full-scale data recovery or mitigation operation since
it is not intended to alleviate adverse impacts or
resolve conflicts with a proposed project. The
appropriate number of units to excavate for evaluative
purposes will vary according to site characteristics
such as horizontal and vertical extent, artifact
density, and structural complexity. In some cases, a
single excavation unit will be appropriate. In others,
several units systematically or judgementally placed
across the site area will be required. Natural and
artificial exposures, such as stream cut-banks and
vehicle trails, should be used where possible to
supplement data from excavation units.
3.5.2.2 Significance Criteria
There are several kinds of significance, including
scientific, public, ethnic, historic and economic, that
need to be taken into account when evaluating
archaeological resources. For any site, explicit
criteria are used to measure these values. Checklists of
criteria for evaluating pre-contact and post-contact
archaeological sites are provided in Appendix D and
Appendix E. These checklists are not intended to be
exhaustive or inflexible, and the user should add to and
revise them as necessary. Innovative approaches to site
evaluation which emphasize quantitative analysis and
objectivity are encouraged. The process used to derive a
measure of relative site significance must be rigorously
documented, particularly the system for ranking or
weighting various evaluatory criteria.
Site integrity, or the degree to which an archaeological
site has been impaired or disturbed as a result of past
land alteration, is an important consideration in
evaluating site significance. In this regard, it is
important to recognize that although an archaeological
site has been disturbed, it may still contain important
scientific information.
Archaeological resources may be of scientific value in
two respects. The potential to yield information which,
if properly recovered, will enhance understanding of
British Columbia's human history is one appropriate
measure of scientific significance. In this respect,
archaeological sites should be evaluated in terms of
their potential to resolve current archaeological
research problems. Scientific significance also refers
to the potential for relevant contributions to other
academic disciplines or to industry.
Public significance refers to the potential a site has
for enhancing the public's understanding and
appreciation of the past. The interpretive, educational
and recreational potential of a site are valid
indications of public value. Public significance
criteria such as ease of access, land ownership, or
scenic setting are often external to the site itself.
The relevance of archaeological resource data to private
industry may also be interpreted as a particular kind of
public significance.
Ethnic significance applies to archaeological sites
which have value to an ethnically distinct community or
group of people. Determining the ethnic significance of
an archaeological site may require consultation with
persons having special knowledge of a particular site.
It is essential that ethnic significance be assessed by
someone properly trained in obtaining and evaluating
such data (i.e. ethnologists, behavioral scientists,
etc.).
Historic archaeological sites may relate to individuals
or events that made an important, lasting contribution
to the development of a particular locality or the
province. Historically important sites also reflect or
commemorate the historic socioeconomic character of an
area. Sites having high historical value will also
usually have high public value.
The economic or monetary value of an archaeological
site, where calculable, is also an important indication
of significance. In some cases, it may be possible to
project monetary benefits derived from the public's use
of an archaeological site as an educational or
recreational facility. This may be accomplished by
employing established economic evaluation methods; most
of which have been developed for valuating outdoor
recreation. The objective is to determine the
willingness of users, including local residents and
tourists, to pay for the experiences or services the
site provides even though no payment is presently being
made. Calculation of user benefits will normally require
some study of the visitor population.
3.5.2.3 Assessing Impacts
An archaeological resource impact may be broadly defined
as the net change between the integrity of an
archaeological site with and without the proposed
development. This change may be either beneficial or
adverse.
Beneficial impacts occur wherever a proposed development
actively protects, preserves or enhances an
archaeological resource. For example, development may
have a beneficial effect by preventing or lessening
natural site erosion. Similarly, an action may serve to
preserve a site for future investigation by covering it
with a protective layer of fill. In other cases, the
public or economic significance of an archaeological
site may be enhanced by actions which facilitate
non-destructive public use. Although beneficial impacts
are unlikely to occur frequently, they should be
included in the assessment.
More commonly, the effects of a project on
archaeological sites are of an adverse nature. Adverse
impacts occur under conditions that include:
- destruction or alteration of all or part of an
archaeological site;
- isolation of a site from its natural setting; and
- introduction of physical, chemical or visual
elements that are out-of-character with the
archaeological resource and its setting.
Adverse effects can be more specifically defined as
direct or indirect impacts. Direct impacts are the
immediately demonstrable effects of a project which can
be attributed to particular land modifying actions. They
are directly caused by a project or its ancillary
facilities and occur at the same time and place. The
immediate consequences of a project action, such as
slope failure following reservoir inundation, are also
considered direct impacts.
Indirect impacts result from activities other than
actual project actions. Nevertheless, they are clearly
induced by a project and would not occur without it. For
example, project development may induce changes in land
use or population density, such as increased urban and
recreational development, which may indirectly impact
upon archaeological sites. Increased vandalism of
archaeological sites, resulting from improved or newly
introduced access, is also considered an indirect
impact. Indirect impacts are much more difficult to
assess and quantify than impacts of a direct nature.
Once all project related impacts are identified, it is
necessary to determine their individual level-of-effect
on archaeological resources. This assessment is aimed at
determining the extent or degree to which future
opportunities for scientific research, preservation, or
public appreciation are foreclosed or otherwise
adversely affected by a proposed action. Therefore, the
assessment provides a reasonable indication of the
relative significance or importance of a particular
impact. Normally, the assessment should follow site
evaluation since it is important to know what
archaeological values may be adversely affected.
The assessment should include careful consideration of
the following level-of-effect indicators, which are
defined in Appendix F:
- magnitude
- severity
- duration
- range
- frequency
- diversity
- cumulative effect
- rate of change
The level-of-effect assessment should be conducted and
reported in a quantitative and objective fashion. The
methodological approach, particularly the system of
ranking level-of-effect indicators, must be rigorously
documented and recommendations should be made with
respect to managing uncertainties in the assessment.
Next Page >> | 
