Archaeological Impact Assessment Guidelines
3.0 Archaeological Impact Assessment and Review
Process
Part 4 of 4
The management of unavoidable and unanticipated
adverse impacts on archaeological resources is achieved
through the implementation of mitigation, compensation,
surveillance, monitoring and emergency impact management
measures. These measures are only implemented in
situations where unavoidable conflicts are identified
between archaeological resources and a proposed
development. The nature and extent of these measures
will have been determined in the impact assessment
stage.
In practice, defining the optimum level of impact
management is hindered by the fact that archaeological
resource values and preservation benefits are not easily
measured in economic terms. Determining publicly and
professionally acceptable levels will usually
necessitate discussion with the Branch. The overriding
objectives are to promote efficiency and equity, and
ensure that the benefits of such measures exceed the
costs.
Mitigation refers to measures that reduce the
deleterious effects of project construction, operation
and maintenance on archaeological resource values.
Actions designed to prevent or avoid adverse impacts are
also regarded as mitigation.
In the case of mitigative management, some form of
systematic data recovery, analysis and interpretation
will be involved. The proponent and/or his archeological
consultant will be required to submit a detailed
research proposal to the Branch prior to implementation.
This level of study involves the effective,
professional management of endangered archaeological
sites within the project area. The primary objectives
are to:
- implement acceptable measures for mitigating
adverse impacts or compensating for resource losses;
- report the objectives, methods and results of
impact management; and
- report the need for and general scope of any
follow-up surveillance or monitoring.
Various options are available for the mitigation of
adverse impacts on archaeological sites including
changes in project design, the implementation of site
protection measures, and systematic data recovery. The
mitigative measure(s) which should be implemented in any
specific case depends on:
- the significance of the resource;
- the nature and extent of the impact;
- the relative effectiveness of the measure;
- research and resource management priorities and
needs; and
- project objectives, conditions and constraints.
An important means of mitigating adverse project
impacts on archaeological sites is to institute changes
in the design or location of a project, or to alter the
level of development intensity. Design alternatives are
recommended in the impact assessment study and
subsequently incorporated in the final project design.
Alterations in project design are viable mitigation
measures wherever adverse impacts on archaeological
sites are avoided or reduced as a result. Impacts can be
avoided by relocating project facilities such as
construction camps, stockpiles and transmission towers,
or re-aligning linear developments such as oil and gas
pipelines, transmission lines, railways, and roads.
Fences or other suitable barriers should be erected,
despite avoidance measures, as an added precaution where
archaeological sites are situated close to a
construction area. Avoidance is always the preferred
mitigation measure as it ensures complete in situ
protection of the resource for future investigation or
use. Moreover, it is often the least costly measure to
implement.
Reducing the effects of project actions on
archaeological sites can also be accomplished by
decreasing the amount of development or by using
construction practices which minimize ground
disturbance. Examples include restricting the use of
heavy machinery on a site, clearing land over suitable
snow cover, and using project buildings without
subsurface foundations.
Archaeological preservation can also be achieved
through measures that prevent or forestall site
destruction. Site protection measures include protective
covering, stabilization, and physical barriers. The
feasibility and suitability of implementing one or other
of these protective measures may require a geophysical
assessment.
Site capping or burial involves judiciously covering
an archaeological site with fill, asphalt, peat,
concrete, etc. Once capped, project construction or
other activities may be permitted to occur unimpeded
over the site. However, site capping is an appropriate
mitigative measure only when it can be demonstrated that
important data will not be irrevocably lost through
compaction, accelerated decomposition, horizontal
displacement, or subtle changes in soil chemistry. In
addition, capping must take into account the degree to
which future investigation and use may be foreclosed
because of inaccessibility.
Stabilization measures and the use of protective
barriers may be appropriate in cases where
archaeological sites are adjacent to the construction
zone, and in areas where erosion or slope failure are
anticipated. Under these conditions, the destruction or
erosion of archaeological sites may be prevented by
constructing barriers such as fences, dykes and gabions,
or by utilizing landscaping practices such as
differential clearing and slope terracing. Water
diversion channels, designed to minimize erosional
processes, may also be considered protective barriers.
In addition, a suitable buffer zone, within which no
land alteration or other activity is permitted, is often
necessary to ensure adequate site protection. Buffer
width should depend on the degree of uncertainty
concerning site size and the type of activity proposed.
Archaeological site vandalism and the unlicensed
collection of artifacts and "digging" of sites, are
often indirect consequences of a project. Vandalism may
be precipitated by disclosing site locations or by
facilitating public access to otherwise inaccessible
areas. Although site protection measures can play an
important role in controlling vandalism, other
approaches are usually required. Since site vandalism is
primarily an educational problem, one approach is to
conduct information programs for project personnel that
promote archaeological conservation. In addition, the
development of archaeological sites as special interest
areas can also serve to deter vandalism, while allowing
the resource to be of direct public benefit. An ongoing
program of patrolling and monitoring archaeological
sites should also be considered.
The systematic investigation and recovery of data
from archaeological sites represents a third, but less
desirable, mitigation option. A principle disadvantage
is that the recovery process itself is destructive;
foreclosing future opportunities for scientific
research, preservation or public appreciation.
Furthermore, even the most intensive and sophisticated
recovery program is seldom able to retrieve all the data
in an archaeological site; invariably a great deal of
information is lost. Proper data recovery and analysis
is also very time consuming and expensive, and recovery
costs are often difficult to estimate accurately.
Therefore, systematic data recovery should be considered
only as a last resort when both avoidance and site
protection measures are impractical.
Where data recovery is the only viable mitigative
option, it should be based on an adaptive, flexible
research design and employ professionally accepted
methods and techniques. Data recovery should aim to
generate further scientific understanding and enhance
public appreciation and awareness of the resource.
Multi-disciplinary collaboration and problem-oriented
research are encouraged.
Archaeological research goals will vary depending on
current regional research and resource management
priorities and needs. However, once defined, the
specific research problems and objectives constitute the
limits of a proponent's responsibility in data recovery
and analysis. The level or intensity of data recovery
will depend on the number of sites involved, site
significance, size and structural complexity, and the
level of adverse effect. Because proper understanding of
an archaeological site depends on knowledge of the
larger settlement/subsistence system into which it fits,
adequate mitigation may require investigation of other
unaffected sites.
Systematic data recovery from archaeological sites
involves:
- a complete or partial systematic surface
collection, excavation, or both;
- a comparative analysis and interpretation of
content and contextual information; and
- production of an investigative report.
All recovered data must be analyzed,
interpreted and reported, and artifact curation must be
arranged beforehand. The materials and records of the
investigation must be available and accessible to future
researchers.
The unavoidable loss of significant archaeological
resources as a result of project impacts should be
compensated in-cash or in-kind. Compensation in-cash
refers to direct monetary payment. The Branch will
determine, depending on equity and efficiency
considerations, to whom the payment should be made.
Compensation in-kind refers to measures other than
direct cash payment. An important form of compensation
in-kind is the acquisition of property, unaffected by
project development, for the purpose of establishing
archaeological reserves. In principle, the land or
archaeological property to be acquired should be
equivalent to the foreclosed resources in terms of
topographic setting, types of resources, integrity,
significance and other factors. Site surveys or
investigations, including systematic data recovery in
areas unaffected by a project, may also be suitable
compensative measures.
Compensation in-kind also includes a wide range of
public-oriented archaeological programs and specific
investigative projects. These programs, whether of
local, regional or provincial scale, are often of a
thematic nature and include site restoration,
reconstruction or development. The objective is to
enhance public understanding and awareness of
British Columbia's archaeological resources.
Surveillance is undertaken in order to protect
archaeological resources during project construction by
ensuring compliance with and proper execution of adopted
mitigation measures; particularly any conditions or
restrictions on the nature of construction or level of
development. Surveillance may be necessary where
archaeological site protection measures are implemented
both before and during project construction.
Monitoring is undertaken to ensure that adverse
project impacts on archaeological sites which could not
be predicted or evaluated prior to construction are
addressed. Project actions that may unexpectedly expose
and disturb recorded as well as previously unknown sites
warrant at least periodic monitoring. For example, the
shoreline of a newly created reservoir should be
monitored during the stabilization period to document
unanticipated impacts on archaeological sites resulting
from slope failure and shoreline erosion. In addition,
monitoring is undertaken in order to assess the
effectiveness of mitigation measures, as well as the
magnitude, severity or duration of an impact.
It is occasionally necessary to implement emergency
measures to mitigate unanticipated impacts on
archaeological sites. These measures may be required
where mitigation efforts are found to be ineffective or
fail outright, or where project actions have
inadvertently uncovered significant archaeological
sites.
Emergency impact management involves one or more of
the following actions:
- avoidance through partial or complete project
redesign or relocation;
- application of site protection measures; and
- salvage or emergency excavation.
Salvage excavation implies rapid data recovery with
little or no opportunity for problem-oriented research.
The principal objective is simply to recover data which
would otherwise be lost. Salvage excavation differs
significantly from systematic data recovery, which is
initiated before construction. Neither strategy is
intended to replace the other.
In situations where unpredicted impacts occur,
construction activities must be stopped and the Branch
should be notified immediately. The overriding
objective, where remedial action is warranted, is to
minimize disruption in construction scheduling while
recovering archaeological data.
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