Description of main environmental impacts and proposed mitigation

Air quality

There is the potential for temporary increases in levels of deposited dust and surface soiling due to factors including earthworks for site preparation and during the construction period. This may impact sensitive receptors such as ecological (woodland, watercourses) and human receptors (residential and non-residential receptors) up to 200m from the scheme. Construction activities such as piling, earthworks, excavating and other works in dry working areas will contribute to this impact.

Works resulting in bank and soil erosion (combined with construction activities including excavation and piling) have the potential to enhance dust emissions enhanced by factors including dry weather and wind. Plant and vehicles (site vehicles, piling rigs etc.) will emit pollutants, with such emissions also having the potential to impact local air quality.

Any temporary TM or lane closures required during the scheme may result in an increase in associated vehicle emissions through idling vehicles and increased congestion.

Please see section Road Drainage and the Water Environment for dust-related impacts on the water environment.

No likely significant effects are anticipated, with all air quality effects localised, temporary and managed through best practice measures. Following completion of the works, there will be no changes to traffic flow characteristics (composition, speed or flows).

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:

  • Materials that have a potential to produce dust will be removed from site as soon as possible, unless being re-used on site. Where materials are to be re-used on site, such as excavated riverbed material this will be covered 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 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.

Further measures to minimise emissions will also be followed, such as:

  • All plant and fuel-requiring equipment utilised during construction will be well maintained to minimise emissions.
  • When not in use, plant and vehicles will be switched off and there will be no idling vehicles.
  • Green driving techniques will be adopted, and effective route preparation and planning undertaken prior to works. 

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

Cultural heritage

There are no statutory cultural heritage assets located within the scheme extents, with four Category B Listed Buildings are located within 300m, the closest situated 220m from the works. As the works are highly localised and confined to the area beneath the Bridge and adjacent access field, there is no potential for direct physical impacts on any identified designated cultural heritage features. Additionally, the surrounding topography and existing vegetation provide natural visual screening meaning no indirect impacts to setting or the wider zone of visual influence are anticipated.

There remains a low potential for the discovery of previously unrecorded archaeological remains during construction, due to the nature of the works, with excavations within the riverbed and previously undisturbed areas.

The Bridge and access field are listed on HER and NRHE databases, however, do not have statutory protection. As such, the overall risk of significant cultural heritage impacts is considered low.

The following mitigation measures will be in place:

  • Should the works encounter any archaeological or heritage features, the Amey Environment Team will be notified.
  • Plant and machinery will be stored within the designated site compound and storage areas when not in use.

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

Landscape and visual effects

The works will introduce temporary construction activity into the local landscape, including plant, machinery and a site compound. This will result in a short-term adverse impact on the local landscape character and visual amenity. However, impacts are expected to be limited as the works are located beneath the Bridge, within the channel, banks, and temporary works in adjacent land. Visual receptors are only transient, and as such no significant temporary visual effects are anticipated.

Minor vegetation clearance will be required for access to the works area and riverbanks; however, this will not alter views to or from the Bridge or affect the wider landscape character.

Operationally, there will be a visual change, from the installation of scour protection measures including retaining walls and rock nets. These features are expected to integrate naturally, with reinstated vegetation and natural regrowth helping to enhance the visual amenity over time. The completed works will not alter the local LCT and given the confined nature of the works beneath the structure, no significant operational landscape or visual impacts are expected.

The following mitigation measures will be in place:

  • Throughout all stages of the works, the site will be kept clean and tidy, with materials, equipment, plant and wastes appropriately stored to minimise any potential impacts upon landscape and visual effects.
  • Works will avoid encroaching on land and areas where work is not required or not permitted. This includes general works, storage of equipment, plant and parking.
  • Upon completion of the works, the land where the site compound is located will be returned to its previous state and bank used for the ingress/egress ramp will be reinstated, such as through the use of suitable grass seed mix and local species.

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

Biodiversity

Construction activities have the potential to have a temporary adverse impact on biodiversity primarily through disturbance associated with construction noise (piling and excavation) and prolonged three-month construction presence. These activities may temporarily disturb protected species within the wider area. To minimise these risks to terrestrial species, the following mitigation will be implemented:

  • General construction safeguards will be implemented to protect mammals that may be using the site.
  • Artificial lighting will be minimised as the works will occur during daytime working hours in summer. If required, it will be directional and task-specific to avoid disturbance.
  • Pre-construction bird surveys will be undertaken prior to the works. If nesting birds are identified within the works area, appropriate species-specific mitigation will be implemented, such as protection of any active nests.

Giant hogweed and Himalayan balsam are recorded within and upstream of the works area. In the absence of mitigation, construction activities could lead to the accidental spreading of INNS. An INNS Method Statement has been prepared to manage this risk, where works within 7m of the identified INNS can’t be avoided. This details biosecurity measures and general construction safeguards to mitigate against the disturbance and spread of such species such as:

  • ‘Check, Clean, Dry’ protocol prior and after any in river works.
  • An Environmental Briefing on Invasive Plants and Giant Hogweed will be delivered to site operatives prior to the works commencing.
  • If any member of the site team identifies previously unrecorded stand of INNS or protected species, it will be reported to the Ecological Clerk of Works (ECoW) immediately.

Works within the River South Esk SAC have potential to impact aquatic species through disturbance, changes in flow conditions and potential pollution events. To minimise the risk:

  • Ongoing engagement with the Esk Rivers and Fisheries Trust and Esk District Salmon Fishery Board has informed the recommended in-water working window (1st June to 30th September) to avoid the sensitive period (1st October to 28th February inclusive).
  • Works will be undertaken within a dry working area, with flow maintained in the adjacent channel to ensure upstream and downstream fish migration.
  • A fish rescue will be undertaken by the Esk District Salmon Fishery Board prior to dewatering for the cofferdam installation.
  • The appointed contractor will implement a Pollution Prevention Plan, including silt control, spill response measures and appropriate storage of fuels and chemicals.
  • Appropriate protection of the pump inlet to avoid drawing in aquatic life and other debris will be in place during dewatering.

Under the HRA process, a Stage 1 Screening and Stage 2 Statement to Inform Appropriate Assessment have been completed for the scheme and its impact on the integrity of River South Esk SAC, in line with NatureScot consultation. The HRA concluded that the works have potential for Likely Significant Effects (LSE) on the qualifying features of the SAC, however with mitigations applied, the overall integrity of the River South Esk SAC and conservation status will be maintained.

An ECoW, appointed by the Contractor and independently of Amey will be present on site during the works to ensure compliance with working methodologies and authorisations and licences. An Amey Ecologist will also undertake ad-hoc site visits basis throughout the construction period to provide additional ecological oversight.

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

Geology and soils

Construction activities have the potential to result in localised disturbance to soils and superficial deposits, through excavation of the riverbed and banks and piling works. These activities will temporarily expose the riverbed and soil material, before scour protection measures are installed.

There is a risk of sediment mobilisation during excavation and riverbed preparation, which could impact downstream water quality once normal channel flow is returned to normal. In addition, there is potential for pollution and contamination of soils and from accidental spills, or leaks of fuel from plant and machinery during construction.

Excavation and piling activities may disturb soils along the riverbank, potentially leading to localised soil erosion. Temporary disturbance to the topsoil may reduce soil structure and fertility until reinstatement is complete. In addition, removal of the retaining wall is likely to generate concrete dust, which may cause minor short-term adverse impacts on surrounding soils.

Site access, and the compound will be located within the northwest field, with the prolonged (approximately three-month) presence of the compound and storage areas having potential to compact soil within the grassed area. However, the area already contains matting from previous works (2023) and full reinstatement will be undertaken post construction.

The following mitigation measures will be implemented:

  • The appointed contractor will implement a Pollution Prevention Plan, as reviewed by Amey, including silt control, spill response measures and appropriate storage of fuels and chemicals.
  • Appropriate handling and storage of soils and handling material, with stockpiles located at least 10m from the River South Esk.
  • Plant and machinery will be restricted to designated access routes and working areas to minimise unnecessary ground disturbance.
  • Appropriate reinstatement of the landscape, including site compound and storage areas will be undertaken post-construction.
  • The local weather forecast will be monitored throughout the construction period, with construction activities temporarily halting in the event of high rainfall or wind.

Further mitigation measures in relation to pollution prevention and control measures are detailed within the Road Drainage and the Water Environment section below.

With mitigation measures in place there is no significant effect anticipated on geology and soils. Therefore, in accordance with DMRB Guidance document LA 109: Geology and soils no further assessment is required.

Material assets and waste

Construction of the scour repair works will require the use of materials such as concrete, steel, rock nets, rock mattress and geotextiles. Plant, machinery and vehicles will be required during the construction period, with fuel and oil required. There is potential for resource depletion through the use of primary materials such as aggregates, and transportation of other materials required.

Excavation of the river bed will produce waste material, where it is unsuitable to be reused on site. This material will require off-site disposal at SEPA-authorised facilities. Where materials are not reused throughout the scheme or recycled locally there is potential to increase waste to landfill and contribute to additional pressure on landfill sites, however, the volume of waste produced on site is not anticipated to be significant to contribute to landfill pressure.

Where feasible, the existing rock bags and mattresses from temporary works will be re-used on site to aid with the scour protection designs, thus reducing the quantity of new materials required. Other 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.

The scheme will likely require future maintenance, which may result in the generation of waste and requirement for materials. However, it is anticipated that minimal maintenance will be required, with the scheme designed to a high specification with specialist scour mitigation products with a long design life.

A Site Waste Management Plan (SWMP) will be prepared as the scheme value exceeds £350,000. This will detail how resource use and waste arising from the works will be managed throughout the scheme. This will help control and reduce the amount of waste produced, resulting in less landfilled waste. Furthermore, waste materials will primarily be recycled at a licenced facility, thereby reducing the amount sent to landfill and promoting circular economy practices. All waste will be transported by suitable licenced contractor and have a valid Waste Transfer Note (WTN).

Sampling and testing of materials will be undertaken in accordance with the requirements for Waste Acceptance Criteria (WAC) to ensure compliance with the Criteria and Procedures for the Acceptance of Waste at Landfills (Scotland) Direction 2005. WAC testing helps determine the suitability of the excavated material for reuse or disposal, ensuring compliance with environmental regulations and preventing potential contamination.

The following mitigation measures will be implemented:

  • Waste will be stored in suitable, covered containers, and segregated at the source where possible.
  • Waste will be taken off site in a timely manner and will not be allowed to accumulate in large quantities.
  • 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, such as netting.
  • Operators will have a duty of care ensure the safe handling, storage, and transfer of waste. This includes maintaining proper documentation and ensuring that waste is only transferred to licensed carriers.
  • The waste hierarchy (Reduce, Reuse, Recycle and Dispose) will be employed throughout the construction works.

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

Noise and vibration

Construction activities, including excavation, piling and the movement of plant and machinery will generate temporary increases in noise and vibration. Plant and machinery such as excavators, piling rigs, soil compactors and dumpers will be used, with soil compactors and piling rigs typically producing the highest vibration levels. These activities have the potential to cause short-term disturbance to NSRs.

The nearest NSR is located over 200m from the works. At this distance, and given the screening effect of the bridge structure, carriageway, topography and vegetation, noise and vibration levels are not likely to exceed baseline noise levels at the surrounding receptors. All works will be carried out during day-time working hours, further reducing the potential for disturbance.

TM may also contribute to short-term increases in traffic noise, particularly during peak periods if congestion occurs.

Given the distance to receptors, localised and temporary nature of the works, no significant noise and vibration impacts are anticipated. 

Mitigation measures during the construction period 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, such as piling rigs, 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.

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 site operatives prior to works.
  • Pre-notification of the works through appropriate signage, and social media to inform local residents and road users of the upcoming works.

No adverse operational noise or vibration impacts are anticipated. The scour repair works are confined beneath the Bridge, and will not alter the traffic speed, flows or composition of the A90 carriageway, and ambient noise levels are expected to return to pre-construction conditions.

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

Population and human health

During construction, temporary impacts may arise from increased noise, vibration and construction traffic, as well as short-term disruption to WCH routes and agricultural land. Temporary land take will be required for access to the site from adjacent farmers’ fields, with contact details of the affected landowners supplied to the Contractor prior to commencement of the works. Amey will make initial enquiries for access, however, it is the Contractor’s responsibility to obtain access permissions, where required.

The contraflow system is likely to temporarily impact the bus stops located north of the scheme extents, and they will likely be temporarily closed during the works, however, alternative provisions will be implemented, with no permanent change to access or provision post-construction.

Human health determinants such as noise, and air quality will likely experience temporary increases, however, due to the nature and scale of the works no discernible health impact is expected.

The following mitigation measures will be implemented:

  • Where WCH routes are affected by the works, alternative provisions or clearly signposted alternative routes will be provided.
  • Due to the prolonged nature of the works (three-months), the works, including TM arrangements and programming will be advertised in advance through signage and online communication release.
  • Access and egress for local residents, landowners and agricultural operations will be maintained throughout the construction period.
  • Discussions with local transport operations will be undertaken where bus stop alterations are required.

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 works have the potential for temporary adverse impacts on the water environment, particularly with works to occur within the River South Esk. Silt pollution caused by working in the water environment will be minimised or prevented by keeping water out of the working area using appropriate isolation techniques, through the use of a coffer dam. In addition, appropriate pump rates will be used to avoid disturbance of the river bed.

Pollution incidents, such as accidental spills of fuels, oils, concrete washout or mobilisation of sediments could directly or indirectly impact the River South Esk and its designated features.

The scheme is located within an NVZ; however, works do not require the use of nitrate-rich materials and is not expected to pose a risk to nitrate pollution. Site controls will be in place, including the secure storage of materials, wastes, chemicals and soils to prevent runoff from the site compound and minimise the risk of such materials entering surface or groundwater.

Exposure of the riverbed within the dry working area may result in localised sediment disturbance during activities such as removal of rock bags, excavation and regrading. When the flow is reintroduced upon completion of the works, there is potential for sediment remobilisation which could temporarily affect water quality. The works will be undertaken in a phased programme, limiting the extent of riverbed exposure at any one time and reducing the potential disturbance during construction.

The installation of cofferdams will temporarily divert and constrict flow, increasing velocities within the remaining open channel. Hydraulic modelling undertaken by Amey’s Flooding and Water Team modelled the expected flow velocities during the temporary works, with the potential for increased scour and erosion during the construction period. To mitigate this, temporary scour protection will be installed to stabilise exposed areas, minimise steps in the river and prevent scour during construction.

The Contractor will be responsible for design of the temporary works however; Amey are operating as the Principal Contractor and Temporary Works Coordinator and therefore will review all information relating to the temporary works designs to ensure they are suitable for site and flow conditions.

From the 1st of November 2025, SEPA regulates water environment activities under the Environmental Authorisations (Scotland) Regulations 2018 (EASR). At the time the application for the works was submitted (October 2025), engineering works in the water environment were authorised under the Controlled activities (Scotland) Regulations 2011. As such, the authorisation will be transferred by SEPA from a CAR licence to an EASR permit.

The following mitigation measures will be implemented:

  • A copy of the granted EASR permit, and its supporting application documents will be kept on site and all conditions and measures stated within the authorisation will be adhered to.
  • The appointed contractor will implement a Pollution Prevention Plan, including silt control, spill response measures and appropriate storage of fuels and chemicals.
  • Silt mitigation measures will be implemented, including:
  • Cleaning rock bags/nets prior to installation.
  • Installing rock bags/nets with limited drop heights to minimise sediment disturbance.
  • Any site compounds will have appropriate pollution prevention measures, such as silt netting.
  • Spill kits will be available at all times on site, with all operatives trained in their use. Regular inspections of the spill kits will be undertaken to ensure they are fit for use.
  • 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 throughout and following the works.
  • Operatives will be aware of the environmental risks and sensitivities associated with the scheme, including:
  • European designated status, and senility of the River South Esk SAC.
  • INNS biosecurity measures.
  • Pollution prevention measures.
  • Regular environmental briefings will be delivered on water pollution prevention.
  • All operatives will be aware of SEPA’s Guidance for Pollution Prevention (GPP) documents, including GPP 1, 5, 6, 8, 13, 21, 22 and 26.
  • The Amey control room will be contacted if any pollution incidences occur (24 hours, 7 days a week), and in the event of a pollution incident SEPA will be notified without delay.
  • Where possible, biodegradable lubricant and biodegradable hydraulic oil in plant will be used.
  • Prior to cofferdam removal and rewatering, the dry working area will be fully cleared of materials, debris, plant and equipment and will be checked for any pollution sources.
  • Weather conditions will be monitored throughout the works, with activities halted during adverse of flood events. The Contractor will maintain a contingency plan in if damage to the dry working area occurs.
  • Concrete mixing and washing areas will be located within a designated, impermeable area within the site compound, and at least 10m from the River South Esk. Where a concrete pump must be positioned within 10m of the river, for example for concrete mattress installation, this will only occur after dewatering and the pump will be placed on hardstanding to prevent ground contamination.

With adherence to SEPA’s GPPs, EASR permit conditions and the above mitigation measures, significant effects on road drainage and the water environment are not anticipated. In accordance with DMRB Guidance document LA 113: Road drainage and the water environment no further assessment is required.

Climate

Construction activities associated with the proposed works have the potential to generate greenhouse gases (GHGs) through the use of construction plant, vehicles and machinery, transportation of materials and wastes to and from site, and from embodied carbon within construction materials.

Minor, temporary air quality impacts may also arise from vehicle movements and machinery exhaust emissions. However, given the nature of the scheme, the volume of materials required to be imported on site is not significant. Where possible, existing materials such as suitable rock bags will be reused on site, reducing the need for new materials and associated emissions.

The River South Esk catchment is located within a future Potentially Vulnerable Area, where the highest flood risk is projected to occur during the 2028-2034 cycle. This reflects the increasing likelihood of more and intense flood events within the catchment attributed to climate change. The proposed scour protection works will enhance the long-term resilience of the Bridge by reducing vulnerability to future high-flow events, erosion and scour. The scheme therefore supports the continued safe and reliable operation of the asset under future climate scenarios. This aligns with Transport Scotland’s Approach to Climate Change Adaption & Resilience, contributing to the wider objective of ensuring that critical infrastructure can respond to, withstand and recover from weather-related impacts.

The following mitigation measures will be in place:

  • Where possible, materials and suppliers will be sourced locally to reduce transport-associated emissions.
  • Where waste is to be disposed of, this will be disposed at local waste management 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 and Air Quality section.

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