Description of main environmental impacts and proposed mitigation

Air quality

Impacts

  • On site construction activities carry the potential to produce airborne particulate matter, dust and generate emissions that may have a temporary impact on local air quality levels and act as a nuisance to nearby residents.
  • Perth and Kinross Council’s declared AQMAs will be unimpacted by the works due to the scheme’s general containment within the M90 Friarton Bridge box girders and the minor nature of the proposed scheme.

Mitigation

  • Best practice and measures as outlined in the ‘Guidance on the assessment of dust from demolition and construction (January 2024)’ published by the Institute of Air Quality Management (IAQM), which includes the following mitigation relevant to this scheme will be followed:
  • Materials that have a potential to produce dust will be removed from site as soon as possible, unless being re-used on site (stockpiles will be covered or fenced to prevent wind whipping);
  • Cutting, grinding or sawing equipment will be fitted or used in conjunction with suitable dust suppression techniques such as water sprays or local extraction, e.g. suitable local exhaust ventilation systems;
  • Vehicles carrying wastes and materials will be covered when entering and leaving the work area to prevent escape of materials during transport;
  • Equipment will be readily available on site to clean any dry spillages and spillages will be cleaned up as soon as reasonably practicable after the event using wet cleaning methods; and
  • When not in use, plant, vehicles and Non-Road Mobile Machinery (NRMMs) will be switched off and there will be no idling vehicles.
  • Plant, vehicles and NRMM will be regularly maintained, paying attention to the integrity of exhaust systems to ensure such fuel operated equipment is not generating excessive fumes.
  • Green driving techniques will be adopted, and effective route preparation and planning will be undertaken prior to works.
  • Where possible, materials will be sourced locally.
  • Surfaces will be swept where loose material remains.
  • Operatives will limit impacts relating to indoor air quality using the following measures:
    • The use of sheeting to contain dust;
    • The use of face masks whilst carrying out dust generating activities;
    • Regular clean up of the site; and
    • The use of Heating, Ventilation and Air Conditioning (HVAC) systems.

No significant effects are predicted on air quality. Therefore, in accordance with DMRB Guidance document LA 105: Air Quality no further assessment is required.

Cultural heritage

Impacts

  • Noise and vibration levels at the cultural heritage assets are likely to be similar during the works to those during the current day-to-day operation of the carriageway (i.e. from noise from HGVs etc.).
  • There is the potential for impacts to the ‘Perth, Friarton Bridge; Bridge’ HER.
  • No impacts are anticipated regarding the Kinfauns Castle listed building and the Limeyhaugh Fishing Lodge Canmore due to factors including the works minor nature, its containment within the M90 Friarton Bridge box girders and the general distance from the works area to the designations in question.

Mitigation

  • Due to the scheme being undertaken within a non-designated culturally significant asset, consultation has been undertaken with the relevant regulatory bodies (Perth and Kinross Heritage Trust and HES) to ascertain whether further impacts/mitigations could be identified. No concerns or additions were raised by either body regarding potential impacts with regard to the works.
  • During construction, plant, vehicles, personnel, materials etc. will be contained to hardstanding areas within the bridge access points and within the box girders at all times.

With mitigation measures in place, no significant effects are predicted on cultural heritage. Therefore, in accordance with DMRB Guidance document LA 106: Cultural Heritage, no further assessment is required.

Landscape and visual effects

Impacts

  • No operational impacts are predicted for visual receptors and landscape character as works will mostly be contained within the box girders of the Friarton Bridge and temporary site compounds being contained within designated areas beneath the structure.
  • Visual amenity may be reduced by the scheme during the transportation of materials/wastes/operatives to and from the bridge access points / site compounds for nearby visual receptors.

Mitigation

  • Works will be contained within the M90 Friarton Bridge box girders (with access gained via bridge access points at either end of the structure). Site set-up and any storage areas required will be out with potential site lines where possible in order to minimise visual impacts on nearby receptors.
  • Screening will be utilised where applicable/relevant to alleviate visual impacts during deliveries, materials/waste storage etc.

The residual effect on landscape and visual effects is deemed to be neutral. Therefore, in accordance with DMRB Guidance document LA 107: Landscape and Visual Effects no further assessment is required.

Biodiversity

Impacts

  • There is potential for protected species to be active within the surrounding area and for the works to result in disturbance to these species via impacts including pollution (air quality, noise and vibration etc.).
  • The scheme does not have the potential to spread the INNS and Transport Scotland Target Species identified due to works being contained within the box girders. The presence of the site compound will be within hard-standing areas at either end of the structure.
  • Due to their distance from the scheme extents (and the schemes containment within the box girders and designated hard-standing areas), no impacts are anticipated on the ancient woodland identified within 500m.
  • The scheme has the potential to impact the River Tay SAC (if uncontrolled) via pollution events such as spillages into the surrounding water environment.

Mitigation

  • An HRA has been undertaken to assess the impacts of the scheme upon the aforementioned designated European sites. No direct impacts or significant effect pathways are anticipated for the qualifying interests of the European sites, with the works in question taking place within the box girders (essentially indoors). Noise, visual disturbance and water and air pollution risks will be appropriately minimised by standard pollution and noise controls. The HRA concluded that no likely significant effects were posed on the site as a result of the scheme taking place.
  • In the event that protected species are sighted, works will temporarily be suspended until the animal has moved on. Any sightings will be reported to the Amey ET&S team. The ET&S team will be contacted for any guidance if required, and the control room will be contacted for environmental record.
  • All works and storage of plant, machinery, vehicles and equipment will be restricted to the boundaries of the M90 Friarton bridge box girder access points and within the box girders themselves.
  • Noise mitigation measures as outlined in the Noise and Vibration section and pollution control mitigations as outlined in the Road Drainage and the Water Environment section will be adhered to during the works.
  • Due to the scheme not being included as a construction activity within the appropriate Marine Licence (Bridge Maintenance - M90 Friarton Bridge, Perth - 00009957 Marine Licence, set to expire in December 2032) currently in place for the M90 Friarton Bridge, consultation was undertaken with the Marine Directorate to ascertain whether the works can be carried out without further licencing input being required. The Marine Directorate responded on 12/03/2025 stating that a variation to the current Marine Licence for Friarton Bridge must be undertaken to allow the works to proceed. All relevant conditions of the issued marine licence variation will be adhered to throughout the scheme.

With mitigation measures in place, no significant effects are predicted on biodiversity. Therefore, in accordance with DMRB Guidance document LA 108: Biodiversity, no further assessment is required.

Material assets and waste

Impacts

  • The works will result in contribution to resource depletion through use of virgin materials.
  • GHG emissions will be generated by material production and transportation to and from site.
  • Transportation and recovery of materials/waste will require energy deriving from fossil fuels, a non-renewable source.

Mitigation

  • Materials will be derived from recycled, secondary or re-used origin as far as practicable within the design specifications to reduce natural resource depletion and associated emissions.
  • It is Amey policy to reuse or recycle as much waste material as possible. Where reuse is not feasible, waste material will be removed to a licenced waste facility.
  • Where possible, different waste streams will be separated at the source.
  • Waste will be stored in suitable containers and covered.
  • A SWMP will be completed for the scheme.
  • The waste hierarchy (Reduce, Reuse, Recycle and Dispose) will be employed throughout the construction works. Waste contractors will adhere to the duty of care with regards to the disposal of removed materials.

With best practice mitigation measures in place, no significant effects are predicted on Material Assets and Waste. Therefore, in accordance with DMRB Guidance document LA 110: Material Assets and Waste, no further assessment is required.

Noise and vibration

Impacts

  • During the scheme, noisy works (such as the construction of a site-compound) will likely be required for prolonged periods (albeit, during daytime hours), which could cause disturbance for residential properties within 300m of the scheme extents, non-residential receptors and for the nearby amenity users.

Mitigation

  • Plant/machinery will be fitted with silencers/mufflers.
  • No plant, vehicles or machinery will be left idling when not in use.
  • A soft start to the works will be undertaken, whereby plant/machinery will be turned on sequentially as opposed to simultaneously.
  • Amey’s environmental briefing on noise and vibration will be delivered to operatives prior to the start of construction.

With best practice mitigation measures in place, and due to the works being of a minor, temporary, transient nature, no significant effects are predicted for noise and vibration. Therefore, in accordance with DMRB Guidance document LA 111: Noise and Vibration and no further assessment is required.

Population and human health

Impacts

  • No TM is required for the scheme, therefore; no impacts are predicted on the on/off-sips present at either end of the Friarton Bridge.
  • Due to the scheme’s general containment within the box girders and designated hard-standing areas, no impacts are anticipated on the Perth and Kinross Council Core Paths identified nearby.
  • There will be no impact on land take from private land, community facilities or agricultural land as a result of the scheme as all works will be contained within the carriageway boundary.

Mitigation

  • Site specific control measures regarding noise and vibration, landscape and visual effects and air quality can be found in the relevant sections (above).

With best practice mitigation measures in place, no significant effects on population and human health are predicted. Therefore, in accordance with DMRB Guidance document LA 112: Population and Human Health, no further assessment is required.

Road drainage and the water environment

Impacts

  • If not adequately controlled, debris and runoff from the works could enter surrounding surface water environment. In the event of a flooding incident, this debris may be mobilised and could enter the road drainage system, thus having a detrimental effect on the surrounding local water environment.
  • Potential for spills, leaks or seepage of fuels and oils associated with plant to escape and reach drainage systems and watercourses if not controlled, which may negatively affect the surrounding water environment.
  • Should flooding occur, this may delay the scheduled works.
  • The scheme has the potential to impact the River Tay Water watercourse via pollution events.
  • Due to the containment of the scheme within the Friarton Bridge box girders and designated hard-standing areas, the Strathmore and Fife (including Finavon) NVZ will not be impacted by the scheme.

Mitigation

  • All debris which has the potential to be suspended in surface water and wash into the local water environment will be cleaned from the site both during and following the works.
  • Appropriate measures will be implemented onsite to prevent any potential pollution to the natural water environment (e.g., debris, dust, and hazardous substances). This will include spill kits being present onsite at all times, and the use of funnels and drip trays when transferring fuel etc.
    • The Amey control room will be contacted if any pollution incidences occur (24 hours, 7 days a week).
  • Visual pollution inspections of the working area will be conducted frequently, especially during heavy rainfall and wind.
  • Weather reports will be monitored prior to and during all construction activities. In the event of adverse weather/flooding events, all activities will temporarily stop and only reconvene when deemed safe to do so.
  • All storage of materials/fuel and any refuelling activities will be more than 10m away from any drainage inlet at all times and placed on a hardstanding surface.
  • Storage areas will be located away from areas that see high vehicular movement to prevent accidental damage.
  • All oils and fuels will be returned to storage area after use.
  • Amey’s environmental briefing on water pollution prevention will be delivered to operatives prior to the start of construction.
  • All site operatives will be made aware of the location of the River Tay prior to works commencing.
  • All operatives will be briefed on SEPA’s Guidance for Pollution Prevention (GPP) documents (namely, GPP 1, GPP 2, GPP 5, GPP 6, GPP 8, GPP 21 and GPP 22).
  • Due to the scheme not being included as a construction activity within the appropriate Marine Licence (Bridge Maintenance - M90 Friarton Bridge, Perth - 00009957 Marine Licence, set to expire in December 2032) currently in place for the M90 Friarton Bridge, consultation was undertaken with the Marine Directorate to ascertain whether the works can be carried out without further licencing input being required. The Marine Directorate responded on 12/03/2025 stating that a variation to the current Marine Licence for Friarton Bridge must be undertaken to allow the works to proceed. All relevant conditions of the issued marine licence variation will be adhered to throughout the scheme.

With best practice mitigation measures in place (and the relevant Marine Licence), no significant effects on road drainage and the water environment. Therefore, in accordance with DMRB Guidance document LA 113: Road Drainage and the Water Environment, no further assessment is required.

Climate

Impacts

GHG emissions will be emitted through the use of machinery, vehicles and materials used (containing recycled and virgin materials) and transporting to and from site.

Mitigation

  • Local suppliers will be used as far as reasonably practicable to reduce travel distance and GHG emitted as part of the works.
  • Vehicles/plant will not be left on when not in use to minimise and prevent unnecessary emissions.
  • Further actions and considerations for this scheme are detailed in the above Material assets and waste section.

With best practice mitigation measures in place, the residual significance of effect on climate is considered to be neutral. Therefore, in accordance with DMRB Guidance document LA 114: Climate, no further assessment is required.

Vulnerability of the project to risks

As the works will be limited to works contained within the M90 Friarton Bridge box girders, there will be no change in vulnerability of the road to risk, or in severity of major accidents/disasters that would impact on the environment.

It has been determined that the project is not expected to alter the vulnerability of the existing trunk road infrastructure to risk of major accidents or disasters.

Assessment cumulative effects

The Scottish Road Works Commissioner's Interactive Map and Amey’s current programme of works have not yet highlighted any ongoing works on/surrounding/within the Friarton Bridge within the timescales involved however, this is due to the works taking place in September 2025 and sporadically thereafter.

Works being undertaken as part of the NE NMC on the Friarton Bridge in the coming months include electrical upgrades within the box girders (25-NE-1203-7) (June/July 2025), drainage upgrades (22-NE-1203-006) (April 2025), security fence upgrades (24-NE-1203-11) (August 2025), gully replacements (24-NE-1203-2) (ongoing) and edge beam spalling (22-NE-1203-003) (ongoing). Due to the minor nature of the scheme, combined with its containment within the box girders of the Friarton Bridge and designated hard-standing areas (and the lack of TM involved), cumulative impacts are not anticipated as a result of the scheme.

Perth and Kinross Council’ Planning Portal has not highlighted any planning applications of note during the timescale involved, or at the location of the scheme.

No other nearby schemes which may result in a combined effect on nearby receptors have been identified.

Any future schemes will be programmed to take into account already programmed works, and as such any effect (such as those from potential construction noise) will be limited.