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Cumulative effects can
result from an accumulation of effects from numerous activities or from a combination of effects from one activity. In either
case, cumulative effects can be different in nature (e.g. synergistic), larger
in magnitude, greater in significance, more long-lasting, and/or greater in
spatial extent than is the case with individual effects. The amount of data
required to identify and predict cumulative effects is likely to be much
greater than for individual effects, as is the extent and complexity of data
manipulation. Increased data requirements mean increased costs (and time). The
expected results must be weighed carefully against the resources required. Much
uncertainty already exists with the identification and prediction of
environmental effects. This is only increased with cumulative effects,
particularly as manipulative and synergistic effects are considered. Methods
available for environmental impact analysis are not directly applicable to
cumulative impact analysis because they usually address only first-order,
cause-effect relationships. Thus, methods have to be developed or adapted for
use in CIA. Cumulative effects may not be restricted to the area in which the
activity is taking place, and indeed may cross political (i.e. district and
regional) boundaries. This poses a potential problem in that inter-district
co-operation and co-ordination may be required for addressing cumulative
effects, but the institutional framework for accomplishing this may not be in
place.
The concept of Territorial Impact
Assessment (TIA) has been proposed in the European Spatial Development
Perspective (ESDP). Whilst the concept itself is not defined, it is suggested
in the ESDP that it should be used as an instrument for the spatial assessment
of large infrastructure projects and as the basis for integrated spatial
development strategies for environmentally sensitive areas. In the ESDP, the
concept is clearly related to the assessment of the impact of projects, rather
than plans or programmes. As a spatial planning instrument, it is expected that
TIA can be applied to any spatial scale. In most other EU member states the
concept of TIA is new to planning practice, although in several it is possible
to identify major planning studies, which are perhaps comparable in terms of
scope and purpose. This may occur, for example, whenever national planning
bodies have needed to evaluate possible new airport locations or other major
infrastructure proposals. TIA is a tool or procedure for assessing the impact
of proposed spatial development against spatial policy objectives or prospects
for an area. In principle, TIA includes all aspects of spatial planning whether
they are environmental, social, economic or cultural in their impact. Thus a
TIA could consider the impact of a proposed policy on, for example, job
opportunities, the housing market, the regional economy, the cultural heritage
or tourist attractions. |