Description of main environmental impacts and proposed mitigation

Air quality

Impacts

TM implemented during the scheme may result in an increase in vehicle emissions through idling vehicles and increased congestion along the diversion route. This may result in a temporary deterioration in local air quality.
During construction activities, such as removal of old road surface, there is the potential for an increase in dust and emissions from plant and machinery. This is likely to cause a slight deterioration in air quality within the local area.
Residents along the diversion route may experience a deterioration in air quality due to the increased volume of traffic.
The impacts identified will be temporary for the duration of the works only and therefore no permanent change is predicted on air quality.

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:
Remove materials that have a potential to produce dust from site as soon as possible, unless being re-used on site (cover or fence stockpiles to prevent wind whipping);
Only use cutting, grinding or sawing equipment fitted or in conjunction with suitable dust suppression techniques such as water sprays or local extraction, e.g. suitable local exhaust ventilation systems;
Minimise drop heights from conveyors and other loading or handling equipment;
Ensure vehicles entering and leaving the work area are covered to prevent escape of materials during transport;
Ensure equipment is 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; and
When not in use, plant, vehicles, and Non-Road Mobile Machinery (NRMM) will be switched off and there will be no idling vehicles.

The following additional mitigation measures will be implemented:

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.

No significant effects are anticipated and therefore no further assessment is required in accordance with DMRB Guidance document LA 105: Air Quality.

Cultural heritage

Impacts

There are no designated cultural 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 to non-designated sites such as Castle Douglas High School or Hillowton Country House and Stables.
The potential for the presence of unknown archaeological remains within scheme extents is considered low as original construction of the A75 would likely have removed any features of archaeological significance, and works are to be restricted to the existing carriageway boundary.

Mitigation

During construction, plant, vehicles, personnel, materials etc. will be contained to hardstanding areas within the carriageway boundary.
If any archaeological finds are discovered, they will not be removed, and the Energy Transition & Sustainability team will be contacted for further advice.

Providing all works operate in accordance with current best practice, no significant effects are predicted on cultural heritage and therefore in accordance with DMRB Guidance document LA 116: Cultural Heritage, no further assessment is required.

Landscape and visual effects

Impacts

There will be a short-term impact on the landscape character and visual amenity of the site due to the presence of construction plant, vehicles, and TM.
During nighttime programming, misdirected site lighting may cause disturbance to surrounding residential properties, particularly those along Garden Hill Avenue.
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.

Mitigation

Throughout all stages of the works, the site will be kept clean and tidy, with materials, equipment, plant and wastes appropriately stored, reducing the landscape and visual effects as much as possible.
Plant, vehicles, and materials will be contained to hardstanding areas within the carriageway boundary (as far as reasonably practicable). If damage to the landscape occurs, reinstatement will be carried out.
Temporary site lighting will be directional and pointed at the works area only.

With mitigation measures and best practice in place, it is anticipated that any landscape and visual effects associated with the works are unlikely to be significant. Consequently, in accordance with DMRB Guidance document LA 107: Landscape and Visual Effects, no further assessment is required.

Biodiversity

Impacts

Construction activities have the potential to cause a temporary adverse impact on biodiversity due to vehicle presence, noise and artificial site lighting during nighttime works. These may disturb protected species within the surrounding area.
Works will be confined to the carriageway boundary, involving like-for-like carriageway resurfacing with no earthworks. As such, INNS or target species will not be introduced to the scheme.
There will be no impact on Loch Ken and River Dee Marshes SPA and Ramsar.

Mitigation

Any artificial lighting will be pointed directly at the works to minimise impact on nocturnal species.
If a protected species is encountered, works will be paused and advice sought from Amey’s Environmental Team.
Vehicles and materials will not be stored or parked on grass verges where possible. Where damage occurs, the reinstatement of the grass verge will be carried out.
‘Soft start’ techniques will be utilised with noise heavy equipment/plant/machinery in order to avoid disturbance to any potential noise sensitive species present in the area.
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.

A Habitats Regulations Appraisal has been undertaken and has concluded that there will be no Likely Significant Effects (LSE) on Loch Ken and River Dee Marshes Special Protection Area and Ramsar.

The construction works will result in a minor risk of indirect noise, vibration, water and air pollution, but these risks are appropriately mitigated by standard best practice pollution and noise controls. There will be no direct impact on the European Sites or their qualifying features.

With the above mitigation measures and best practice being adhered to, no significant effects on biodiversity are anticipated. Therefore, in accordance with DMRB Guidance document LA 108: Biodiversity, no further assessment is required.

Material assets and waste

Impacts

There is potential for resource depletion through the use and transportation of primary materials such 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.
There will be an increase in waste to landfill sites if waste materials are not recycled or reused.
The design life for the TS2010 surfacing proposed is estimated to be 20 years. This will reduce the requirement for maintenance to this section of road over the period.
Transportation and recovery of materials/waste will require energy deriving from fossil fuel, a non-renewable source.

Mitigation

The Contractor will comply with all ‘Duty of Care’ requirements, ensuring that any surplus materials or wastes are stored, transported, treated, used, and disposed of safely without endangering human health or harming the environment. All waste transfer notes and/or waste exemption certificates will also be completed and retained.
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.
Uncontaminated road planings arising from the works will be fully recycled under a SEPA Paragraph 13(a) Waste exemption in accordance with guidance on the Production for Fully Recovered Asphalt Road Planings.
From November 1^st 2025 these exemptions will be phased out in favour of Environmental Authorisations (Scotland) Regulations (EASR). However, where planings meet SEPA’s criteria, they will be fully recycled.
All special waste, such as tar (if found during the works) will be transported by a suitably licenced contractor and will be accompanied by a correctly completed special waste consignment note (SWCN) providing information about the waste, the producer and the person the waste is being handed to; the SWCN will be kept for three years, the Site Responsible Manager is responsible for ensuring these are retained onsite.
All waste leaving the site will be removed from site by a licenced waste carrier. All waste documentation will be provided when requested.

It has been determined that the proposed project will not have direct or indirect significant effects on the consumption of material assets or creation of waste. Therefore, in accordance with DMRB Guidance document LA 110: Material Assets and Waste, no further assessment is required.

Noise and vibration

Impacts

There will be an increase in noise and vibration levels, for properties within 300m, during works due to the use of plant and machinery and an increase in HGVs. However, as the works are of short duration, the impact on residents will be minimal.
Additionally, Castle Douglas High School will primarily be used during daytime hours, thus the impact will likely be minimal.
However, cattle at Hillowton Dairy Farm may be disturbed.
There will be an increase in noise and vibration for properties along the diversion route, particularly Ernespie Road, King Street, and Abercromby Road due to an increase in vehicles.
TS2010 road surfacing has superior durability and noise reducing features compared to standard road surfacing mixes. Vehicle travellers and nearby receptors will benefit from the improved road surfacing as a result of the scheme.

Mitigation

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.
On-site construction tasks will be programmed to be as efficient as possible, with a view to limiting noise disruption to local sensitive receptors such as Hillowton Dairy Farm. 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.
The site supervisor will monitor the effects of noise and vibration levels during the works and make necessary working arrangements.
A ‘soft start’ to works will be in place, whereby plant/machinery/vehicles are started sequentially as opposed to simultaneously.

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

A letter drop will be delivered to residents and sensitive receptors within 300m to notify them of upcoming works, timings and duration.
Consultation with Dumfries and Galloway Council regarding nighttime working.
Amey’s Noise and vibration environmental briefing will be delivered to all site operatives before works start.

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

Population and human health

Impacts

Construction activities may cause temporary disruption to road users due to TM, noise and delays. There will be an increased journey length of 3 minutes due to the diversion route through Castle Douglas. However, impacts are expected to be minor, as works are scheduled overnight and outside peak traffic hours.
TM will not impact access to any residential properties but will redirect users of Hillowton Dairy Farm to use a different entrance.
Land take is not required for this scheme therefore there will be no impact as a result of permanent or temporary land acquisition from private land, businesses, agriculture, Walkers, Cyclists or Horse riders (WCH) and/or community facilities as a result of the scheme.
The laybys will be closed during construction, however there are no tourist sites or public buildings near the scheme, so the impact to road users will be minimal.

Mitigation

TM restrictions/arrangements and any expected travel delays will be publicised within the local and wider area, in an effort to minimise disturbance to vehicular travellers.
Temporary site lighting used throughout the scheme will be directional and pointed only at the area of works.
Hillowton Dairy Farm, will be notified of the works well in advance of the start of construction.

With best practice mitigation measures in place, no significant effects associated with Population and 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

Construction activities may pose a risk of indirect pollution to the water environment from spills, leaks or seepage of fuels and oils associated with plant to escape and reach drainage systems and watercourses if not controlled.
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. No other post construction impacts are anticipated.

Mitigation

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 following the works.
Debris and dust generated as a result of the works will be prevented from entering the drainage system. This can be via the use of drain covers or similar.
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 control room will be contacted if any pollution incidences occur (available 24 hours, 7 days a week).
Visual pollution inspections of the working area will be conducted in frequency, especially during heavy rainfall and wind.
Weather reports will be monitored prior 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, and run-off/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.

Providing all works operate in accordance with current best practice, as detailed within SEPA’s GPPs, the effects on Road Drainage and the Water Environment are considered not significant. Therefore, in accordance with DMRB Guidance document LA 113: Road drainage and the water environment no further assessment is required.

Climate

Impacts

Construction activities may result in GHG emissions from the use of machinery, vehicles and materials 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.

Mitigation

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

As the works will be limited to the like-for-like resurfacing of the carriageway, 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.

All mitigation measures will be adhered to onsite which considers the vulnerability of the project to be low.

Improvement of the road surface following carriageway resurfacing works will enhance skid resistance, and thus overall road safety on completion of the scheme.

Assessment cumulative effects

Amey’s Southwest Current Works Schedule, and the Scottish Road Works Commissioner, indicate that there are no other works to be carried out within the proposed works time and location.

Dumfries and Galloway Council’s Planning Portal also does not indicate any scheduled works that will be carried out in the proposed works location and time.

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

Overall, the proposed works are unlikely to have any significant cumulative effects with other planned activities in the area. Given the nature and scale of the maintenance works, no in combination effects are anticipated.

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