Description of main environmental impacts and proposed mitigation

Air quality

Construction activities may temporarily affect local air quality due to dust and particulate emissions generated during milling of the carriageway surface. Short-term increases in emissions from construction plant, and vehicles are also anticipated during the construction phase only.

TM will involve a contraflow system, which may result in short-term increases in traffic-related emissions on the A9. Such effects are anticipated to be temporary, localised and limited to the construction period.

There will be no changes to traffic flow characteristics, including vehicle competition, speed or flows, and therefore no operational air quality impacts are anticipated.

During the construction phase, mitigation measures will follow best practice guidance from the Institute of Air Quality Management (IAQM), from the ‘assessment of dust from demolition and construction (January 2024)’ including:

  • Site layout will be planned (including plant and vehicles) so that machinery and dust causing activities are located away from receptors, as far as reasonably practicable.
  • Materials that have a potential to produce dust, such as planings 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).
  • Drop heights from conveyors and other loading or handling equipment will be minimised.
  • Vehicles entering and leaving the work area will be covered/sheeted to prevent escape of materials during transport.
  • Equipment will be readily available on site to clean any dry spillages and clean up spillages as soon as reasonably practicable after the event using wet cleaning methods.

The following additional mitigation measures will be implemented:

  • When not in use, plant and vehicles will be switched off and there will be no idling vehicles.
  • All plant and fuel-requiring equipment used during construction will be well maintained to minimise emissions.

No significant air quality effects are anticipated. Therefore, in line with DMRB Guidance document LA 105: Air quality no further assessment is required.

Cultural heritage

There are no designated or non-designated cultural heritage features within the scheme extents, and no land acquisition is required. All works are confined to the existing carriageway surface, and no significant vibration effects are anticipated due to the nature and scale of the works. Therefore, there is no anticipated impact to the statutory features located over 500m from the scheme extents.

The original construction of the A9 and associated infrastructure likely removed any archaeological remains, and the potential for unknown archaeology is considered low.

There will be no changes to the road alignment or land take, and therefore no operational impacts on cultural heritage.

The following mitigation measures will be in place during the construction phase:

  • Plant and machinery will be stored within the carriageway boundary where practicable.
  • Any access beyond the carriageway will be minimised and ideally limited to foot access.

No significant effects are anticipated to cultural heritage. Therefore, in line with DMRB Guidance document LA 106: Cultural Heritage Assessment, no further assessment is required.

Landscape and visual effects

Overall construction activities will be small-scale and contained within the existing A9 carriageway boundary. Short-term visual effects may arise from the presence of construction plant, TM and artificial lighting. These effects will be localised and temporary, with no anticipated change to the wider landscape character. Furthermore, no constant visual receptors are present, and the works are scheduled to occur overnight for approximately five nights, further reducing visibility and disruption.

No residual landscape or visual impacts are anticipated post-construction, with the improved road surface being the only visible change.

The following mitigation measures will be in place during construction:

  • The site will be kept clean and tidy throughout all stages of the works, with appropriate storage of materials, equipment, plant and waste.
  • Works will avoid encroaching on land and areas where work is not required or not permitted, including for storage and parking.

No significant effects are anticipated upon the landscape and visual effects. Therefore, in line with DMRB Guidance document LA 107: Landscape and Visual Effects no further assessment is required.

Biodiversity

Construction activities have the potential to cause temporary adverse impacts on biodiversity due to vehicle presence, noise and artificial site lighting during the night-time works. This may disturb protected species within the scheme surroundings. 

INNS have been recorded adjacent to the scheme extents; however, works are contained to the existing carriageway boundary, and the absence of land-take, site clearance, or topsoil import reduces the risk of their spread or introduction.

The culvert and field drain located within the scheme extents pose a potential pathway to pollute aquatic habitats, particularly during milling operations and periods of heavy rainfall (see Road Drainage and the Water Environment section for further details).

The scheme will not fragment or remove habitats as no vegetation clearance, land take, or earthworks required. As such, there are no anticipated impacts to habitat connectivity and no overall operational impacts on biodiversity are anticipated.

The following mitigation measures will be in place during construction:

  • A ‘soft start’ procedure with regard to plant, machinery and vehicles will be implemented daily to gradually increase noise levels and minimise disturbance.
  • Directional site lighting will be aimed away from sensitive ecological features such as woodland and watercourses.
  • If a protected species is encountered, works will be paused and advice sought from Amey’s Environmental Team.
  • Additional pollution prevention measures are detailed in the Road Drainage and the Water Environment 
  • As part of the Network Management Contract, Amey, on behalf of Transport Scotland, has been asked to keep a record of various target species, including rosebay willowherb. Works will not cause the spread of these species, if a possibility arises wherein works are likely to result in the spread of these species through disturbance, the appropriate Amey Landscaping Team will be consulted.
  • Site operatives will be made aware of the location of Giant hogweed prior to commencing works on site and will receive an environmental briefing on Invasive Plants and Giant Hogweed prior to works commencing.
  • Plant, vehicles and materials will be contained to areas of engineered ground and not stored on grass verges to prevent the spread of INNS.
  • Biosecurity measures such as ‘Check, Clean, Dry’ protocols will be implemented for all PPE and plant, and all site staff will be aware of and understand the necessary mitigation procedures.

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

Material assets and waste

There is potential for resource depletion through the use and transportation of primary materials such as aggregates. However, the use of recycled content in the binder and base courses, and the application of TS2010 surfacing which offers enhanced durability and therefore reducing the frequency of future interventions (compared with other stone mastic asphalt (SMA) products) helps mitigate long-term resource use.

Potential impacts related to pollution from materials and waste may result if these are not appropriately managed during construction.

No operational impacts are anticipated on material assets and wastes.

The following regulatory requirements will be adhered to:

  • A SWMP will be prepared prior to the works which will detail how resource use and waste will be managed. This will help control and reduce the amount of waste produced, resulting in less landfilled waste.
  • The Contractor is responsible for the management and disposal of road planings arising from the works. All waste will be managed in accordance with the Environmental Authorisations (Scotland) Regulations 2018, under the relevant SEPA waste authorisation for recovery, reuse or disposal. For example, road planings will be prioritised for recovery or reuse, through recycling into new asphalt, in line with the waste hierarchy. Landfill disposal will only be considered where recovery or reuse options are not practicable.
  • Waste will be transferred to SEPA-authorised facilities by carriers with valid waste carrier registrations. A waste transfer note (WTN) will be completed for removal of waste from site and retained for two years, in line with statutory Duty of Care requirements.

The following mitigation measures will be implemented:

  • Waste will be stored in suitable, covered containers, and segregated at the source where possible.
  • The waste hierarchy (Reduce, Reuse, Recycle and Dispose) will be employed throughout the construction works.
  • Good materials management methods (e.g., ‘just-in-time’ delivery) will be used to minimise and prevent the disposal of unused materials.
  • Containment measures will be in place to prevent debris or pollutants from entering the surrounding environment.

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

Noise and vibration

Construction activities, particularly milling and the use of machinery such as planers and construction vehicles may cause temporary noise and vibration impacts. These are not expected to significantly exceed ambient levels or result in notable disturbance to surrounding NSRs, in particular due to the high baseline noise levels. TM may also contribute to short-term increases in noise due to congestion.

Post-construction, no adverse noise or vibration impacts are anticipated. The improved road surface will not change the traffic speed or flows, and ambient noise levels are expected to return to pre-construction conditions.

Mitigation measures during construction will follow Best Practicable Means as outlined in British Standard (BS) 5228:2009+A1:2014. The standard provides specific detail on suitable measures for noise control in respect to construction operations; for example:

  • Quiet working methods will be employed, including use of the most suitable plant, reasonable hours of working for noisy operations, and economy and speed of operations.
  • Effects from noise will be kept to a minimum through the use of appropriate mufflers and silencers fitted to machinery. All exhaust silencers will be checked at regular intervals to ensure efficiency.
  • Operations will be sequenced to minimise simultaneous use of high-noise equipment, and a ‘soft start’ to works will be in place, whereby plant, machinery and vehicles are started sequentially as opposed to simultaneously.
  • Plant and machinery will be regularly maintained to prevent excessive noise from worn parts or inefficient operation.
  • On-site construction tasks will be programmed to be as efficient as possible, with a view to limiting noise disruption to local sensitive receptors. Where night-works are to be undertaken, the noisiest works will be undertaken before 23:00 where possible.

The following further mitigation measures related to noise and vibration will be in place:

  • The delivery of Amey’s Noise and Vibration environmental briefing to all site operatives before works start.
  • Notification of the works to Stirling Council’s Environmental Health Team due to night-time programming.
  • Delivery of scheme information to NSRs through a letter drop as a pre-construction notification of the works.
  • Engagement and pre-notification of the works through social media prior to commencement of the works to make road users and local residents aware of the upcoming works.

With best practice mitigation measures in place, no significant effects on noise and vibration are predicted. Therefore, in line with DMRB Guidance document LA 111: Noise and Vibration no further assessment is required.

Population and human health

Construction activities may cause temporary disruption to road users due to TM, noise, and delays. There may be short-term disturbance to residential receptors from construction noise, and general construction presence, however, no constant visual receptors are identified. Please refer to the Landscape and Visual Effects section above for an assessment of the visual impacts to visual receptors.

Operationally, the Scheme will not alter access arrangements or traffic flows. The improved road surface will improve ride quality for motorists, therefore resulting in beneficial long-term effects.

Local residents and road users will be informed of the working schedule, in particular the times and durations of the works through a letter drop and pre-construction notice of the works which include journey planning via social media; and signage on approach to scheme extents.

Stirling Council’s Environmental Health Team have been notified of the works.

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

Road drainage and the water environment

Potential impacts on the water environment are anticipated to be limited, temporary and managed through best practice measures as all works are to occur within the existing engineered carriageway.

There is potential for short-term risk of accidental pollution from fuels, oils and other contaminants associated with plant, machinery and materials, and road planings entering surface runoff, drainage systems and surface watercourses. A surface watercourse flows across the scheme extents, which could act as a pathway for pollutants. However, as it is a contained culvert beneath the carriageway, with no in-water works, abstraction or transfers of water from, or discharges to a waterbody, the potential for a direct pollution incident within a waterbody is unlikely.

The scheme lies within a groundwater DWPA, however, as the works are limited to resurfacing of the existing carriageway, with no works or excavations within previously undisturbed ground, the potential for impacts on groundwater quality or mobilisation of contaminants is limited.

The works will not increase the long-term flood risk as they are limited to the existing impermeable carriageway surface, with no alteration to drainage infrastructure or surface water runoff patterns. No other post construction impacts are anticipated.

The following best practice and pollution prevention and control measures will be in place during construction:

  • All operatives will be aware of SEPA’s Guidance for Pollution Prevention (GPP) documents.
  • 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.
  • All site operatives will be made aware of site spillage response procedures and in the event of a spill all works associated with the spill will stop, and the incident reported. Spill kits will also be available within all site vehicles and spill kits will be replenished onsite when required.
  • The Amey control room will be contacted if any pollution incidences occur (24 hours, 7 days a week).
  • In the event of a pollution incident, SEPA will be notified without delay.
  • Weather reports will be monitored prior to and during the works with all construction activities temporarily halting in the event of adverse weather or a flooding event. The works will only continue when it is deemed safe to do so and runoff/ drainage can be adequately controlled to prevent pollution.
  • All storage areas (fuels, machinery, plant, materials) where required will be located/stored:
  • Away (>10m) from surface water drainage systems; and
  • Away from areas that see high vehicular movement (as far as reasonably practicable) to prevent damage by collision or extremes of weather.
  • Where refuelling on site is required, there will be designated refuelling areas, located more than 10m from surface water drainage systems. Additionally, they will be stored within a drip tray, bund or other form of secondary containment with at least 110% of the maximum volume of a single container.
  • The delivery of Amey’s Water Pollution Prevention environmental briefing to all site operatives before works start.

With mitigation measures in place, no significant effects are anticipated on the water environment. Therefore, in line with DMRB Guidance document LA 113: Road Drainage and the Water Environment no further assessment is required.

Climate

Construction activities may result in GHG emissions from vehicles, machinery, material use and production, and transportation. However, given the nature of the scheme, the volume of materials required to be imported on site is low, reducing the overall impact.

The use of HMA supports a longer design life compared to other SMA materials, resulting in reduced whole-life carbon impacts as there is a reduced need for repeat resurfacing, minimised material use, transport emissions and construction waste over the road asset’s lifecycle.

The following mitigation measures will be in place during construction:

  • Where possible, materials and suppliers will be sourced locally to reduce GHG emissions associated with travel distance.
  • Waste disposal will be directed to local licensed facilities.
  • Plant, machinery and vehicles will not be left idling when not in use.
  • Further actions and considerations for this scheme are detailed in the above Material Assets and Waste

With best practice mitigation measures in place, no significant effects are anticipated on Climate. Therefore, in line with DMRB Guidance document LA 114: Climate, no further assessment is required.