Description of local environment

Air quality

The scheme extents cover a largely rural stretch of the M90 carriageway at Balmanno Hill, located between Glenfarg and Bridge of Earn, Perth and Kinross. Baseline air quality surrounding the scheme extents is likely to be influenced primarily by traffic flow along the M90, with secondary sources from agricultural activities. Annual Average Daily Flow (AADF) in 2024 along the M90, approximately 4.5km south of the scheme extents (site number: 20813) was counted at 26,903 total vehicles, with 2,538 (9.4%) Heavy Goods Vehicles (HGVs).

Perth & Kinross Council have one currently declared Air Quality Management Area (AQMA), Perth City for exceedances in nitrogen dioxide (NO2) and fine particulates (PM10). This AQMA is located over 6km from the scheme extents. There are no real-time air quality monitoring stations (Air Quality in Scotland) or any sites on the Scottish Pollutant Release Inventory (SPRI) located within 1km of the scheme extents.

There are no air quality-sensitive receptors, including residential properties or community facilities located within 200m of the scheme extents. The closest receptors are situated over 400m from the scheme extents.

Cultural heritage

A desktop study using Historic Scotland Designations and PastMap identified one designated cultural heritage asset within 300m of the scheme extents, Kilnockie Railway Viaduct, a Category B Listed Building (Reference LB5433), located approximately 300m northeast at NGR NO 15437 14962. Constructed between 1887 and 1890, the viaduct comprises five semi-circular arches of bullfaced masonry.

Kilknockie Viaduct is also recorded under the Historic Environment Record (HER) (Reference MPK8418), with the online records indicating it is located partially within scheme extents. It is classified as a farmstead (Early Modern to Late Modern) and a quarry post (Medieval to Late Modern).

No World Heritage Sites or Inventory Battlefields are recorded within 300m of the scheme extents.

Landscape and visual effects

Landscape

The scheme lies within a predominantly rural setting, characterised by woodland and grazing and arable agricultural land.

Pottiehill Wood, an Ancient Woodland Inventory (AWI) site is located approximately 30m east of the scheme extents (Scotland’s Environment Map). No other statutory or non-statutory landscape designations, including Tree Preservation Orders, are present within 500m or visible from the scheme.

The scheme falls within the Lowland Hill Ranges Landscape Character Type (LCT 382), defined by open, upland landscapes with volcanic ridges and glens, grass moorland and upland pasture, with sparse settlement and visible cultural heritage features like hill forts and historic field boundaries. 

Visual

There are no constant visual receptors of the scheme including residential receptors, core paths or public footways. Transient visual receptors include road users (motorists, public transport users) travelling along the M90, who will experience brief and intermittent views of the scheme.

Biodiversity

Protected areas

There are no local, national or European designated biodiversity sites located within 2km, or with hydrological connectivity to the scheme. This includes Sites of Special Scientific Interest (SSSIs), Local or National Nature Reserves, Special Areas of Conservation (SACs), Special Protection Areas (SPAs) or Ramsar sites (Sitelink).

Pottiehill Wood, listed on the AWI lies approximately 30m east of the scheme extents (Scotland’s Environment Map). No Tree Preservation Orders are located within 500m of the scheme extents.

Field survey

An ecological field survey has been scoped out by a qualified ecologist due to the transient nature of the works and their containment within the trunk road boundary, indicating a low likelihood of significant ecological impact.

Invasive plants

Transport Scotland’s Asset Management Performance System (AMPS) has recorded numerous identifications of rosebay willowherb (Chamerion angustifolium), an injurious weed and Transport Scotland (TS) target species along the southbound verge of the M90 carriageway. The closest identification is recorded 5m from the carriageway boundary. Common ragwort (Jacobaea vulgaris), another injurious weed and TS target species is identified 5m east of the carriageway boundary along the scheme extents.

No invasive non-native species are recorded within 500m of the scheme extents.

Geology and soils

Geology

There are no Geological Conservation Review Sites (GCRS), or geological SSSIs located within 300m (Sitelink).

Bedrock geology comprises (British Geological Survey Geology Viewer):

  • Ballagan Formation - sedimentary mudstone and siltstone from the Carboniferous period (approximately 344.5 million years ago (Mya)).
  • Ochil Volcanic Formation - igneous basaltic-andesite from the Devonian period (approximately 419.2 to 393.3 Mya).

Superficial deposits consist of:

  • Devensian till (Diamicton) - sedimentary deposits formed during the Quaternary period (approximately 116 and 11.8 thousand years ago).

Soils

The local soil type within scheme extents is recorded as brown earths (Scotland’s Soils).

Material assets and waste

Materials

Materials required are as follows:

  • Surfacing, binder and base materials (TS2010 aggregate, AC20 binder, AC32 base and potential for EME2);
  • Road marking materials/paint;
  • Road studs;
  • Vehicle fuel;
  • Oil; and

Materials will be obtained from recycled, secondary, or re-used origin as far as practicable within the design specifications to reduce natural resource depletion and associated emissions. For example, the binder and base courses used for resurfacing will contain a percentage of recycled material.

Wastes

Wastes are anticipated to be carriageway planings which will primarily be recycled at a licenced facility, thereby reducing the amount sent to landfill and promoting circular economy practices.

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.

A Site Waste Management Plan (SWMP) will be prepared prior to the works which will detail how resource use and waste arising from the works will be managed throughout the scheme. This is required due to the scheme exceeding £350,000 in value and will help control and reduce the amount of waste produced, resulting in less landfilled waste. 

Noise and vibration

The scheme is located in a predominantly rural area, where baseline noise levels are primarily influenced by traffic on the M90, with secondary sources from agricultural activity. For AADF details, please refer to the Air Quality section above.

Modelled day-evening-night (Lden) noise levels along the scheme extents range from >75dB to 80 B and night noise levels (Lnight) for the period 23:00-07:00 range from >65dB to 70dB. Lden is a noise indicator for overall annoyance based upon annual average A-weighted long-term sound over 24 hours, with a 5 dB(A) penalty for evening noise (19:00-23:00) and a 10 dB(A) penalty for night-time noise (23:00-07:00) (Scotland’s Noise Map).

There are no noise-sensitive receptors (NSRs) including residential receptors, community facilities and businesses. located within 300m. The nearest receptors are situated over 400m from the scheme extents.

The works are not located within a Candidate Noise Management Area (CNMA) as defined by the Transportation Noise Action Plan (Road Maps) (TNAP).

Population and human health

There are no residential receptors located within 300m, with the closest situated over 400m north.

The works will be fully contained within the carriageway boundary, requiring no land take from residential, agricultural, business, or community land, and furthermore will not impact access or egress to any such land.

There are no Core Paths within or visible from the scheme extents, and no provision for walkers, cyclists, or horse-riders (WCH) due to the motorway setting.

No laybys, lighting points or bus stops are located along the scheme extents.

Road drainage and the water environment

Surface water

Road drainage along the scheme extents comprises filter drains and top-entry gullies.

There are no watercourses located within 500m of the scheme extents, including statutory main rivers designated under the Water Framework Directive (WFD) (Scottish Environment Protection Agency (SEPA) Water Classification Hub). However, numerous field drains are present within 500m, with one culvert crossing the carriageway within the scheme extents at the approximate NGR NO 15258 14498.

Groundwater

The scheme lies within the Glenfarg groundwater body (ID: 150527) which was classified as having a good overall condition under the WFD in 2023 (SEPA Water Classification Hub).

The scheme is not located within a Scottish Government Nitrate Vulnerable Zone (NVZ).

Flood risk

Localised areas of the M90 carriageway within the scheme extents have been identified at risk of pluvial flooding, particularly south of the M90 overbridge and along the culverted field drain. This area has a high (10%) annual probability of surface water flooding (SEPA’s Flood Map).

Climate

Carbon Goals 

The Climate Change (Scotland) Act 2009, as amended by the Scottish Carbon Budgets Amendment Regulations 2025 sets out the statutory framework for reducing greenhouse gas (GHG) emissions in Scotland. The prior annual and interim targets have been replaced by five-year carbon budgets, which sets limits on the amount of GHGs that can be emitted in Scotland.

The proposed carbon budgets are aligned with advice from the UK Climate Change Committee (CCC) and calculated in accordance with the 2009 Act. The 2025 Regulations define the baseline years for emissions reductions as 1990 for greenhouse gases including carbon dioxide, methane, and nitrous oxide, and 1995 for others such as hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride (as set out in Section 11 of the Act). The budgets are as follows:

  • 2026 - 2030: Average emissions to be 57% lower than baseline.
  • 2031 - 2035: Average emissions to be 69% lower than baseline.
  • 2036 - 2040: Average emissions to be 80% lower than baseline
  • 2041 - 2045: Average emissions to be 94% lower than baseline.

These budgets are legally binding and will be supported by a new Climate Change Plan, which will outline the specific policies and actions required to meet the targets.

Transport Scotland remains committed to reducing carbon across Scotland’s transport network, this commitment is being enacted through the Mission Zero for Transport. Transport is the largest contributor to harmful climate emissions in Scotland, and Transport Scotland are committed to reducing their emissions by 75% by 2030 and to a legally binding target of net-zero by 2045. 

Amey’s Company Wide Carbon Goal is to achieve Scope 1 and 2 net-zero carbon emissions, with a minimum of 80% absolute reduction on our emissions by 2035. Amey is aiming to be fully net-zero, including Scope 3 emissions, by 2040. 

Amey are working towards a contractual commitment to have carbon neutral depots on the North East Network Management Contract (NE NMC) network by 2028. Amey have set carbon goals for the NE NMC contract as a whole to be net-zero carbon by 2032.