Archaeological Impact Assessment Guidelines
Appendix F
Indicators for Assessing Impacts on Archaeological
Sites
The amount of physical alteration or destruction
which can be expected. The resultant loss of
archaeological value is measured either in amount or
degree of disturbance.
The irreversibility of an impact. Adverse impacts
which result in a totally irreversible and irretrievable
loss of archaeological value are of the highest
severity.
The length of time an adverse impact persists.
Impacts may have short-term or temporary effects, or
conversely, more persistent, long-term effects on
archaeological sites.
The spatial distribution, whether widespread or
site-specific, of an adverse impact.
The number of times an impact can be expected. For
example, an adverse impact of variable magnitude and
severity may occur only once. An impact such as that
resulting from cultivation may be of recurring or
ongoing nature.
The number of different kinds of project-related
actions expected to affect an archaeological site.
A progressive alteration or destruction of a site
owing to the repetitive nature of one or more impacts.
The rate at which an impact will effectively alter
the integrity or physical condition of an archaeological
site. Although an important level-of-effect indicator,
it is often difficult to estimate. Rate of change is
normally assessed during or following project
construction.
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