Scottish Government: Business, Enterprise & Energy Directorate
Appraisal of the Implications of the proposed Beauly to Denny transmission line development on the River Spey Special Area of
Conservation (SAC)
2009
The following appraisal has been prepared by the Scottish Ministers as the Competent Authority for the above proposal.
1
Project and site description
Brief description of the project
Scottish and Southern Energy (SSE) and Scottish Power (SP) submitted applications to Scottish
Ministers (under section 37 of the Electricity Act 1989) proposing an upgrade of the main electricity
transmission line from the Highlands to the Central Belt. The proposal is to replace the existing 132kV
line from the Beauly substation near Inverness to Bonnybridge in Stirlingshire with a 400kV line from
Beauly to Denny, near Falkirk.
The proposal includes the following:
220km of new double circuit 400kV overhead transmission line on steel lattice towers from
Beauly substation to a new substation near Denny via Fasnakyle.

Development of new or existing substations at Beauly, Fasnakyle, Fort Augustus, Tummel and
Braco substations.

Removal of all the existing 132kV overhead transmission line.
The purpose of the project is to provide the transmission infrastructure to enable new generators in the
north and west of Scotland, to link to centres of demand further south.
2
Brief description of the designated
Natura site
The River Spey is a large Scottish east coast river that drains an extensive upland catchment and
supports an outstanding freshwater pearl mussel population, considered of great international
significance, in its middle to lower reaches.
The River Spey is designated as a SAC for the following Annex II species which are a primary reason
for site selection:
 Atlantic salmon
 Freshwater pearl mussel
 Otter
 Sea lamprey
3
Conservation objectives for the
designated Natura site
The conservation objectives of the River Spey SAC for the qualifying species are:
To avoid deterioration of the habitats of the qualifying species (listed above) or significant disturbance
to the qualifying species, thus ensuring that the integrity of the site is maintained and the site makes an
appropriate contribution to achieving favourable conservation status for each of the qualifying
features; and
To ensure for the qualifying species that the following are maintained in the long term:
 Population of the species, including range of genetic types for salmon, as a viable component
of the site
 Distribution of the species within site
 Distribution and extent of habitats supporting the species
 Structure, function and supporting processes of habitats supporting the species
 No significant disturbance of the species
 Distribution and viability of freshwater pearl mussel host species
 Structure, function and supporting processes of habitats supporting freshwater pearl mussel
host species
4
Screening
Is the proposal directly connected The proposal is not directly connected with, or necessary to, the conservation management of the
with, or necessary to, conservation River Spey SAC and therefore further consideration is needed.
management of the designated
Natura site?
5
Consider whether there are any
likely direct, indirect or secondary
impacts of the project on the
designated Natura site
The proposed 400kV transmission line would cross the SAC at two points, 1km east of Garvamore
and near Dalwhinnie. It would run parallel to the SAC for 8km from 1km west of Melgarve to 1km
east of Garvamore. Near Garva bridge the overhead transmission line would cross the Allt Coire Iain
Oig within 80m of the SAC boundary. Near Dalwhinnie it would cross the River Truim (part of the
SAC) and then run east of the A9 through part of the catchment of the Truim
The proposed access route would follow the line of the proposed 400kV overhead transmission line.
At Garva bridge, the access route would run along or close to the SAC boundary for 440m and then
cross the Allt Coire Iain Oig within 80m of the SAC. Near Spey Dam, the access route would cross the
SAC at the road bridge. Access tracks to the east of the A9 would be in part of the catchment of the
Truim.
The existing 132kV overhead transmission line (to be dismantled as part of this project) runs adjacent
to the SAC near Sherramore,near Catlodge and within the catchment of the Truim, and runs within it
on one additional location near Garva Bridge.
The potential impacts of the proposal are:



Potential for increased watercourse sedimentation within SAC during construction phase. This
could have a significant impact upon salmon spawning beds and/or the gills of salmon juvenile
being smothered and/or also their movements impeded. This could also impact on pearl
mussels which are vulnerable to siltation which can smother mussels living on or in the
riverbed.
There is also a possible risk of contamination of the watercourse from the fuel and chemical
spillages/leaks. Any loss of water quality could adversely affect the salmon and freshwater
pearl mussel interest. Any pollution could also indirectly affect the otter population by
impacting on their prey species (e.g. salmon).
Potential risk of desertion of the territory, particularly by otter, but also possibly by salmon,
during construction through displacement or disturbance, such as noise and vibration from

6
heavy machinery, earth movement, the preparation of foundations and loading/unloading of
machinery. This would constitute a significant disturbance.
As well as any impacts upon salmon, similar effects are also possible on resident trout
populations. This could also indirectly affect the freshwater pearl mussel interest with relies
on juvenile salmon and trout to complete its lifecycle
Consider the key phases of During all phases of the development, but particularly during the construction and dismantling phases,
development and the risk of effects a key consideration is pollution of aquatic habitats which may have a direct toxic effect on the aquatic
associated with each.
protected species, as well as a degradation of their habitats. Pollution can also take the form of silt
laden run-off. This may also have direct effects on species, such as inhibiting of respiration by
affecting gill function in Atlantic salmon and lamprey and filter feeding in mussels. Silt also affects
the habitats of aquatic protected species, such as the infill of salmon redds, lamprey spawning
grounds, mussel beds and otter resting-up sites. Siltation may also result in increased nutrient status
(eutrophication) of the aquatic protected species’ habitat.
During the operation phase, risks are fewer because there will be less activity on site, but accidental
spillages from vehicles or storage areas are still possible and could affect the SAC as described above.
Construction
Construction activities give rise to the risk of direct loss or and/or disturbance of habitats, disruption to
otter travelling routes, pollution and sedimentation of watercourses and impacts upon channel
management.
Operation
The operation phase of the development carries less risk of effects on the specified interests than the
construction phase, due largely to routine maintenance activities.
Dismantling
Dismantling of the existing 132 kV line gives rise to the risk of effects similar to those associated with
the construction of the proposed line, including direct loss and/or disturbance to habitats, pollution,
increased sedimentation etc.
Dismantling of the proposed 400 kV line gives rise to the risk of impacts which are currently hard to
assess given the expected ‘lifespan’ of the line being c. 80 years. Any risks associated with this
dismantling process are likely to be similar to those associated with the construction phase of the
development, and mitigation measures would be required to ensure any impact on the SAC is
minimised.
7
Appraise
which
individual
elements of the overall project
would give rise to the greatest risk
of effects. State any element of
the project where the scale or
magnitude of effect is not known
The elements of the proposal which will give rise to the greatest risk of effects are the construction
phase, the operational phase and the dismantling and removal of the 132kV line.
Construction phase
Construction of transmission line tower bases and towers – The proposed 400kV transmission line
route would be within the catchment area of the River Spey system at several locations. Construction
sites for tower bases and towers of varying distances from the River Spey and associated tributaries
would, therefore, be required at this location.
Construction of borrow pits – Construction of borrow pits may be required in the River Spey
catchment area.
Access track construction – Track upgrades and construction would be undertaken throughout the
length of the transmission line route.
Crossing of waterbodies/watercourses – Fording of waterbodies/watercourses by vehicles and plant
will not be permitted through the entire working corridor of the proposed 400kV line. Where the
crossing of a waterbody/watercourse associated with the River Spey catchment is unavoidable, bridges
will be used in preference to culverts.
Tree felling – Tree felling would be required to be undertaken for the overhead corridor and access
tracks for the proposed 400kV transmission line within the catchment area of the River Spey SAC.
Tree felling would be required within areas of commercial plantation forestry at Sherramuir Forest, to
the north of the proposed crossing point at Garvamore and within areas of plantation to the north of
Drumochter.
Operational phase
Routine maintenance would involve inspection of each tower and conductors approximately every 5-6
years to asses the requirement for remedial works. Maintenance could result in general pollution and
siltation.
Dismantling 132kV line
Removal of transmission line tower bases and towers – The existing line runs from the Corrieyairack
Pass to Etteridge and from Etteridge to Drumochter within the Spey catchment. Sites for the
dismantling of tower bases and towers of varying distances from the River Spey and associated
tributaries would, therefore, be required throughout this area, including six water crossings.
De-stringing of transmission lines – the technique of de-stringing lines uses a method called Catenary
Support System (CSS) which would ensure that conductors are not pulled through
waterbodies/watercourses.
Borrow pits – potential impacts associated with the construction of borrow pits in the dismantling
phase would be consistent with those associated with the construction phase.
Access track construction – Similarly, the construction of access tracks required for the dismantling
phase would have potential impacts like those associated with the construction phase.
Crossing of waterbodies/watercourses – Same as in construction phase.
Tree felling – the potential impacts associated with tree felling on aquatic protected species, namely
increased flows, siltation and acidification.
8
Is the plan/project likely to have a
significant effect on the River
Spey
Special
Area
of

Sea Lamprey: No likely significant effect. Sea lamprey are typically not present in the upper
reaches of large river systems and the furthest upstream known record from the River Spey is
from between Kingussie and Newtonmore.
Conservation, either alone or in
combination, with other plans or
projects?



9
Otter: Likely significant effect. Otter are abundant in the upper reaches of the Spey catchment
through which the development will pass, and are sensitive to disturbance and pollution
(affecting their prey species also).
Atlantic salmon: Likely significant effect as salmon are abundant in the upper reaches of the
Spey catchment and are vulnerable to siltation and pollution of watercourses, and to
disturbance.
Freshwater pearl mussels: Likely significant effects as mussels are known to be present in
some isolated locations in the SAC, and are susceptible to siltation which can smother mussels
living on the riverbed.
Appraisal of Impacts on Site
Integrity
Identify the relevant conservation The conservation objectives to consider are those that relate to the qualifying species and habitat
objectives to consider for the which may be affected by the proposal. These are:
designated Natura site.
To avoid deterioration of the habitats of the qualifying species (Atlantic salmon, otter, freshwater
pearl mussel) or significant disturbance to the qualifying species, thus ensuring that the integrity of
the site is maintained and the site makes an appropriate contribution to achieving favourable
conservation status for each of the qualifying features; and
To ensure for the qualifying species that the following are maintained in the long term:







population of the species, including range of genetic types for salmon, as a viable component
of the site
distribution of the species within site
distribution and extent of habitats supporting the species
structure, function and supporting processes of habitats supporting the species
no significant disturbance of the species
distribution and viability of freshwater pearl mussel host species, and
structure, function and supporting processes of habitats supporting freshwater pearl mussel
host species
10 Can it be ascertained that the The conservation objectives for the site are:
proposal/plan will not adversely
affect the integrity of the River To avoid deterioration of the habitats of the qualifying species (listed above) or significant
Spey SAC?
disturbance to the qualifying species, thus ensuring that the integrity of the site is maintained and the
site makes an appropriate contribution to achieving favourable conservation status for each of the
qualifying features - The proposal crosses the SAC and runs alongside it at other points, and pollution
may affect the quality of the water and consequently the habitats of the SAC, as described below.
To ensure for the qualifying habitats that the following are maintained in the long term:
Otter
 population of the species as a viable component of the site - Otter are abundant in the upper
reaches of the catchment. Pollution from refuelling activities or chemical usage during
construction or dismantling can indirectly affect otters by impacting upon their prey species
(salmon). However, if the mitigation as outlined in the Environmental Statement in relation to
buffer distances is applied, then it is possible to conclude that population within the SAC will
be maintained.

distribution of the species within site – Although otters are able to travel long distances across
a catchment there are circumstances where the local topography, presence of man-made
structures and the river’s flow characteristics combine to impede otter movements, sometimes
resulting in casualties. This might result from the presence of the towers during the operation
phase, or increased sedimentation due to construction activities.

distribution and extent of habitats supporting the species – The extensive home ranges
occupied by otters mean that, provided water quality overall in the river catchment is
reasonably good, small sections of poorer quality water are unlikely to present serious
problems. In addition, where land-use practices in a river catchment area lead to soil erosion
problems, the effects of siltation on salmonoid breeding success may have an indirect impact
on otters.

structure, function and supporting processes of habitats supporting the species – . Otters food
source, Atlantic salmon, require well oxygenated water, low sediment loads and overall
excellent water quality to survive, conditions at risk of being negatively affected by
construction works.

no significant disturbance of the species – Otters are sensitive to disturbance, which might
arise from noise, vibrations etc from construction activities. If the displacement disturbance
resulted in desertion of this territory, this would constitute significant disturbance.
Atlantic Salmon
 population of the species, including range of genetic types for salmon, as a viable component
of the site - The salmon population and its genetic component could be affected by juvenile
salmon gills being smothered by siltation or pollution during construction or dismantling
activities.. Siltation can also smother salmon eggs by clogging the spaces between the gravel
and preventing oxygenated water reaching the incubating eggs.

distribution of the species within site – The loss of Atlantic salmon connected to the SAC by
contamination of watercourses during construction or dismantling may reduce the occupation
of the SAC, and hence the distribution within the SAC.

distribution and extent of habitats supporting the species – The proposal crosses the SAC and
runs alongside it at other points, and pollution from re-fuelling, chemical usage, traffic during
construction, maintenance or dismantling work may affect the quality of the water and
consequently the habitats of the SAC.

structure, function and supporting processes of habitats supporting the species – Atlantic
salmon require well oxygenated water, low sediment loads and overall excellent water quality
to survive.

no significant disturbance of the species – A significant pollution event or noise and vibration
from construction and dismantling activities could constitute significant disturbance to Atlantic
salmon within the SAC. If the disturbance resulted in salmon becoming absent from sections of
the SAC, this would constitute significant disturbance.
Freshwater pearl mussel
 population of the species as a viable component of the site - Pearl mussels are known to be
present in some isolated locations in the upper reaches of the River Spey catchment. Like
Atlantic salmon, freshwater pearl mussels require well oxygenated water, low sediment loads
and overall excellent water quality to survive. This makes the mussels sensitive to pollution,
increased sedimentation and siltation.

distribution of the species within site – Pearl mussels are extremely sensitive to pollution and
sedimentation. Sedimentation could smother pearl mussels living on or in the riverbed. Should
this happen then their distribution within the SAC would become restricted.

distribution and extent of habitats supporting the species – Mussels require very good water
quality and a riverbed with areas of clean gravel and sand. Pollution could cause such habitat
to become unsuitable, thereby reducing the distribution and extent of habitat supporting pearl
mussels.

structure, function and supporting processes of habitats supporting the species – Adult pearl
mussels are able to tolerate some silt for unknown lengths of time, but juveniles are never
found in silty habitat. Juvenile pearl mussels tend to live entirely buried within the river
substrate and are therefore much more vulnerable to any increases in silt or suspended solids
which can smother the gravel bed, preventing the supply of oxygen and organic food particles
to the mussels.

no significant disturbance of the species – The noise and vibration from construction and
dismantling activities could result in significant disturbance to all qualifying interests within
the SAC.

distribution and viability of freshwater pearl mussel host species – as described for Atlantic
salmon, but also applies to trout populations.

structure, function and supporting processes of habitats supporting freshwater pearl mussel
host species – as described for Atlantic salmon habitats, but also applies to habitat supporting
trout populations.
11 Consider
whether
mitigation The Environmental Statement proposes mitigation to address the impacts of the proposed
measures can be adopted to avoid development. The proposed mitigation addresses the requirements as detailed in the previous section
impacts on site integrity
for maintaining the habitats/qualifying species. Additionally, the contractor would follow best
construction site practices at all times and during all stages of construction, including SEPA’s Best
Management Practices, Pollution Prevention Guidelines, and statutory conditions applied through
General Binding Rules or higher CAR authorisations. In addition, the following mitigation measures
are proposed to address the impacts of the proposed development:
(a) In respect of the River Spey Special Area of Conservation (SAC) and the River Spey Catchment
Area as defined by SNH:
• the outside edge of each tower base shall be a minimum of 50m from all watercourses and
water bodies within the SAC and a minimum of 50m within the River Spey Catchment Area
unless other mitigation measures proposed are implemented to permit reductions in the
distance specified;
• the outside edge of all borrow pits, quarries, etc. shall be a minimum of 50m from all
watercourses and water bodies within the SAC;
• The outside edge of all permanent non mobile storage facilities for oil, fuel etc. shall be a
minimum of 100m from all watercourses and water bodies within the River Spey Catchment
Area;
• No re-fuelling shall take place within 30m of watercourses and water bodies within the River
Spey Catchment Area;
• No generators and similar plant and machinery shall be used within 30m from watercourses
and water bodies within the SAC and within 10m from watercourses and 30m of water bodies
within the River Spey Catchment Area;
• No spoil heaps shall be constructed within 30m from watercourses and water bodies within
the River Spey Catchment Area unless other mitigation measures proposed are implemented to
permit reductions in this distance specified;
• No operations involving concrete transfer between vehicles or into vehicles shall take place
within 30m of watercourses and water bodies within the River Spey Catchment Area;
(b) The transmission line shall not be commissioned, i.e. transmit electricity between Beauly and
Denny until a plan for emergency repair/maintenance works within the SAC has been submitted to and
approved in writing by the Scottish Ministers. Any emergency repair/maintenance works shall be
carried out in accordance with the approved plan.
The foregoing conditions shall apply to all operations in respect of both the construction of the 400kV
transmission line and the dismantling of the existing Beauly to Denny overhead transmission line.
Conclusion of Appraisal
12 Can it be ascertained that the
proposal will not adversely
affect the integrity of the River
Spey SAC?
Provided that the mitigation measures outlined in the relevant sections of the Environmental Statement
and in section 11 are adopted and implemented on-the-ground by means of enforceable conditions
attached to any consent (through either the Electricity Act/Town and Country Planning Act or through
CAR regulatory procedures) then the Beauly to Denny overhead line proposal will not adversely affect
the integrity of the River Spey SAC.