Environmental Engineering Reference
In-Depth Information
Impact on the integrity of the priority habitat
Ballyseedy Wood covers a total of 41 h, although the priority habitat that was the subject
of assessment represented only a very small part of this overall area. A small area in the
northern corner of the wood accorded with the definition in the Habitats Directive of a
residual alluvial forest. This northern part of the wood consists of alder and ash and is
subject to regular flooding. Wet woodland of this type is the least common type of Irish
forest, and the surviving examples tend to be small in area; the priority habitat area
covered less than half a hectare. It was this northern edge of the wood that was to be lost
to the proposed dual carriageway, including the areas of greatest ecological interest.
The direct land take of the proposed scheme involved the loss of only 3 per cent of the
total area of the priority habitat. However, this does not necessarily mean that the effect
on the integrity of the habitat would be insignificant. The independent study concluded
that:
On the basis of the assessments carried out by a number of environmental
consultants and the evidence presented to the CPO inquiry, the loss of
habitat could not be objectively assessed as being of no significance to the
integrity of the habitat as a whole. There will be change caused to the
habitat as a result of the removal of trees, the change in the hydrological
regime and the re-routing of the river [another element of the scheme].
Evidence to the CPO inquiry suggested that areas of the wood, outside of
the land take, would also be affected by this change. As part of EU policy
the precautionary principle also needs to be applied to the assessment of
the impact of a project on a priority habitat. In applying that principle it
must be concluded that there is a risk that the integrity of the [habitat] will
be significantly diminished by the proposed road. (Weston & Smith 1999)
It was therefore concluded that the impact on the priority habitat would be negative.
Nevertheless, the project could still go ahead if it satisfied both of the remaining two
tests. The first of these concerned the absence of alternative solutions.
The absence of alternative solutions
The County Council's identification of the preferred route alignment for the proposed
scheme, and possible alternative routes, was based partly on a constraint mapping
exercise in which areas with various environmental constraints (such as archaeological
remains) were identified. Cost factors also featured in the choice of the preferred route,
and a form of CBA was carried out. The Council prepared a Design Report, which set out
the need for the scheme and the alternatives considered. This reveals that the Council had
identified and investigated a number of alternatives. Weston & Smith (1999) identify a
total of six main alternatives to the proposed scheme, including a do-minimum option.
Most of the alternatives considered would completely avoid Ballyseedy Wood, generally
by following more northerly route alignments. However, other adverse impacts would
arise from some of these alternative schemes, such as the demolition of residential
properties, farm severance and the relocation of Ballyseedy Monument, a local war
memorial. Notwithstanding these impacts, a number of viable alternative route options
were clearly available to meet the objectives of the proposed scheme.
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