Description of main environmental impacts and proposed mitigation

Air quality

Construction activities may temporarily affect local air quality due to dust and particulate emissions, particularly during milling of the carriageway surface. Increased HGV and construction plant presence may also contribute to short-term emissions. TM will likely cause congestion and elevated traffic-related emissions during the works.

However, there are no changes to traffic flow characteristics post-construction (composition, speed or flows) and any air quality impacts will be short-term.

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 excavated material, will be removed from site as soon as possible, unless being re-used on site (cover or fence stockpiles 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 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 identified listed building located 300m from the scheme extents.

The non-designated HER within the scheme extents is not expected to be impacted, as the works involve like-for-like resurfacing. The original construction of the M90 and associated infrastructure likely removed any archaeological remains, and the potential for unknown archaeology is considered low.

The following mitigation measures will be in place:

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, no further assessment is required.

Landscape and visual effects

Short-term impacts on landscape character and visual amenity are anticipated during construction due to the presence of TM, construction plant, vehicles and artificial lighting. However, these effects will be limited as all activities will be restricted to made ground on the M90 carriageway; no constant visual receptors are present and the works are scheduled to occur overnight over twelve working days, further reducing visibility and disruption.

Upon completion of the works, no residual landscape or visual impacts are anticipated. The visual appearance of the site will remain largely unchanged, with the improved road surface being the only discernible difference.

The following mitigation measures will be in place:

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. These may disturb protected species within the scheme surroundings.

No invasive non-native species (INNS) have been recorded within the scheme extents. Although injurious weeds such as rosebay willowherb and common ragwort have been recorded along the M90 roadside verges, the absence of land-take, site clearance, or topsoil import significantly reduces the risk of their spread or introduction.

While no watercourses are present within 500m, field drains and a culvert within the scheme extents pose a potential risk of indirect pollution to aquatic habitats, particularly during milling operations and periods of heavy rainfall (see Road Drainage and the Water Environment section for further details).

The following mitigation measures will be in place:

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 used, aimed away from sensitive ecological features such as adjacent woodland.
Plant, vehicles and materials will be contained to areas of engineered ground and not stored on grass verges as far as reasonably practicable. Any damaged areas will be reinstated post-works.
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 section.
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 and common ragwort. 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.

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

Geology and soils

All works are contained to the engineered layers of the existing carriageway, resulting in limited potential for soil disturbance.

In the absence of mitigation, there is a risk of pollution to soils from accidental spills or leaks of fuels and oils from construction plant and machinery. However, any impact is expected to be minor and temporary, with no significant effect on soil function or quality.

The following mitigation measures will be in place:

Vehicles and materials will not be stored or parked on grass verges where possible. Where damage occurs, reinstatement will be undertaken.
Pollution prevention measures outlined in the Road Drainage and the Water Environment section will be followed during construction.

With mitigation measures in place, no significant effects are anticipated on geology and soils. Therefore, in line with DMRB Guidance document LA 109: Geology and Soils 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 reduced maintenance requirements (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. Therefore, 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 disposal of road planings, and this will be registered in accordance with a Paragraph 13(a) waste exemption issued by the SEPA, as described in Schedule 3 of the Waste Management Licensing Regulations 2011.
All waste will be disposed of at SEPA-licenced facilities by carriers with valid waste licences. A waste transfer note (WTN) will be completed every time waste is removed from the site and retained for two years.

At the time of writing, coring investigations have not been undertaken. Coal tar is not anticipated given the scheme’s location and previous coring results along the M90. However, if coal tar is identified within treatment depths, it will be treated as special waste, with the following regulatory requirements adhered to:

All special waste will be transported by a suitable licenced contractor and accompanied by correctly completed special waste consignment note (SWCN) providing information about the waste source, hazardous properties and disposal/treatment facility. The SWCN will be retained for three years.
Special waste will be segregated with general waste and other recyclables.

The following mitigation measures will be implemented:

Operators will follow duty of care protocols for the safe handling, storage, and transfer of waste. This includes maintaining proper documentation and the use of licensed carriers.
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, in particular as no NSRs are identified. 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 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/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:

Amey’s Noise and Vibration environmental briefing will be delivered to all site operatives before works start.

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. However, impacts are expected to be minor, as works are scheduled overnight, outside peak traffic hours, and no full road closures or diversions are required.

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

Please see the Landscape and Visual Effects section above for an assessment of the visual impacts to visual receptors.

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

Construction activities may pose a risk of indirect pollution to the water environment from spills of fuels, oils, chemicals, and road planings entering surface runoff and drainage systems. While no watercourses are located within 500m, a culvert carrying field drainage crosses the scheme which could act as a pathway for pollutants.

The resurfacing works will not increase 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:

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.
Fuels stored within a drip tray, bund or other form of secondary containment with at least 110% of the maximum volume of a single container.
Where refuelling on site is required, there will be designated refuelling areas, located more than 10m from surface water drainage systems, and within hard standing and bunds to prevent leaks or spills escaping.
Amey’s Water Pollution Prevention environmental briefing will be delivered 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 following mitigation measures will be in place:

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 where possible.
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 section.

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.

Vulnerability of the project to risks

Construction activities are confined to the carriageway boundary, reducing the risk of major accidents or environmental disasters. Furthermore, TM will be designed in line with existing guidance. TM will comprise of a contraflow system with lane closures, and therefore with no full road closure or diversion routes required.

Considering the above, the vulnerability of the project to of major accidents and disasters is considered to be low.

Assessment cumulative effects

Perth & Kinross Planning Portal has not identified any extant planning applications surrounding the scheme extents that would result in any in-combination effects.

The Scottish Road Works Commissioner’s Interactive Map has not highlighted any works during the proposed timescale at the location of the works.

Amey’s current programme of works has identified the Phase 2 Glenhead Bridge Refurbishment scheme, ongoing just south of the M90 Balmanno Hill resurfacing works, near Glenfarg.

While programming for both schemes will overlap, the resurfacing works will be coordinated to utilise the existing contraflow TM arrangements in place for the bridge refurbishment. This approach is expected to mitigate additional traffic disruption and minimise congestion impacts.

During construction, activities associated with the works may have minor temporary disturbances such as changes to noise and vibration and air quality, and potential disturbance to local wildlife.

The scheme is not anticipated to have significant environmental effects having regard to its nature, scale and location. The residual impacts arising from the works can be appropriately mitigated and thus no cumulative or in-combination effects are anticipated.

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