Geology, Soils and Groundwater

Introduction

This chapter presents the DMRB Stage 1 geology, soils and groundwater assessment for the six improvement strategies for the A75 Springholm and Crocketford Improvements (hereafter referred to as “the proposed scheme”). This chapter has been produced in line with the Design Manual for Roads and Bridges (DMRB) Design Manual for Roads and Bridges (DMRB) LA 109 – Geology and soils (revision 0) (hereafter referred to as “DMRB LA 109”), DMRB LA 113 – Road drainage and the water environment (revision 1) (hereafter referred to as “DMRB LA 113”) and other relevant guidance.

Sensitive receptors reported within this chapter are typically soils and soils supporting sites of ecological importance, human receptors and controlled waters. Further information on mineral resources is contained in the Material and Wastes Chapter of this EAR. Additional information on biodiversity, human health receptors and controlled waters are detailed in the Biodiversity Chapter, Population and Human Health Chapter and Road Drainage and the Water Environment Chapter of this EAR.

Legislative and Policy Framework

This section provides a summary of the legislation and policy that are relevant to this geology, soils and groundwater assessment.

Legislation

The following legislation is relevant to this geology, soils and groundwater assessment.

The Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2017

Under Schedule 4(4) of these regulations, Environmental Impact Assessment (EIA) reports must include a description of factors likely to be significantly affected (such as human health, land and soils) to be described.

Nature Conservation (Scotland) Act 2004

This Act establishes the framework for conserving and enhancing specific areas of Scotland which are considered to be of particularly high quality in terms of their flora, fauna, or geological or geomorphological features through Sites of Special Scientific Interest.

Part 2A of the Environmental Protection Act 1990, Environment Act 1995

Part 2A, introduced by the Environment Act 1995, provides a legal for identifying and remediating contaminated land. It adopts a risk-based ‘suitable for use’ approach. Guidance is published in Land Contamination Risk Assessment . This framework forms the basis of the contamination assessment undertaken for this scheme.

Groundwater Policy Protection for Scotland

These regulations cover the protection of groundwater in Scotland against pollution.

The Water Environment and Water Services (Scotland) Act 2003 (WEWS)

These regulations cover rivers, lochs, transitional waters (estuaries), coastal waters groundwater and groundwater dependent wetlands.

The Water Environment (Controlled Activities) Scotland 2011

These regulations apply regulatory controls over activities which may affects Scotland’s water environment. The regulations cover rivers, lochs, transitional waters, coastal waters, groundwater, and groundwater dependant wetlands.

Water Environment and Water Services (Scotland) Act 2003

These regulations apply regulatory controls over activities which may affects Scotland’s water environment. The regulations cover rivers, lochs, transitional waters, coastal waters, groundwater, and groundwater dependant wetlands.

Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 (the ‘EU Water Framework Directive’)

These regulations establish a framework for Community action in the field of water policy and apply regulatory controls over activities which may affects Scotland’s water environment. The regulations cover rivers, lochs, transitional waters, coastal waters, groundwater, and groundwater dependant wetlands.

National Policy

The following national policy documents have been taken into account in this assessment:

  • National Planning Framework 4 :
    • Policy 4 Natural places – To protect, restore and enhance natural assets making best use of nature-based solutions.
    • Policy 5 Soils – To protect carbon-rich soils, restore peatlands and minimise disturbance to soils from development.
    • Policy 9 Brownfield, vacant and derelict land and empty buildings – To encourage, promote and facilitate the reuse of brownfield, vacant and derelict land and empty buildings, and help reduce the need for greenfield development.
  • The Scottish Soil Framework :
    • The framework aims to promote the sustainable management and protection of soils consistent with the economic, social and environmental needs of Scotland.

Local Policy and Plans

The following local policies and plans are considered in this assessment:

  • Dumfries and Galloway Local Development Plan 2
    • Policy NE6 – Sites of National Importance for Biodiversity and Geodiversity
    • Policy NE11 – Supporting the Water Environment
    • Policy NE13 – Agricultural Soil
    • Policy NE14 – Carbon Rich Soil
    • Policy NE15 – Protection and Restoration of Peat Deposits as Carbon Sinks
    • Policy IN10 – Contaminated and Unstable Land

Assessment Methodology

Data Sources

The following list provides a summary of the data sources used to collect baseline data and carry out the geology, soils and groundwater assessment.

Assessment Guidance

The methodology described in this chapter is in accordance with the requirements specified in DMRB LA 104 - Environmental assessment and monitoring (revision 1) (hereafter referred to as “DMRB LA 104”), DMRB LA 113 and DMRB LA 109. The level of significance of a potential effect on the existing baseline condition is determined by the sensitivity of the receptor, combined with the magnitude of potential impact.

In compliance with DMRB LA 109, a desktop review has been undertaken to identify potential sources of contamination associated with current and historical land uses, and pathways to receptors in accordance with land contamination risk management guidance and British Standards (BS)10175:2011+A2:2017 Investigation of potentially contaminated sites - Code of practice. A Preliminary Sources Study Report (PSSR) was prepared in parallel to this EAR therefore a complete PSSR was not available to provide input to this assessment. This is proportionate to the level of assessment required at DMRB Stage 1.

The identification of potentially significant effects on geology, soils and groundwater have been derived from a qualitative desk-based assessment. The assessment accounts for the potential impacts across the river catchments as well as groundwater and surface water receptors. The assessment also accounts for relevant aspects of other environmental factors such as biodiversity and landscape. For example, groundwater quality aspects relating to any groundwater dependent habitats of relevance, and/or listed buildings or monuments.

Environmental impacts for geology, soils and groundwater have been expressed in terms of the significance of their effect, both beneficial and adverse.

Table 3.11 of DMRB LA 109 has been used to determine the environmental sensitivity of a receptor, while the magnitude of change is reported in the assessment in accordance with the criteria provided in Table 3.12 of DMRB LA 109. Groundwater and surface water receptors and magnitudes of impact are defined as per the National Highways Departure from Standards (revision 0) which allows for professional judgement and consistency with DMRB LA 113. The sensitivity criteria for groundwater has been based on development of Table 3.70 of DMRB LA 113, while the magnitude of impact criteria has been developed from Table 3.71 of DMRB LA 113. The assessment criteria used in this report are detailed in Table 9-1 and Table 9-2 below.

The approach to deriving impact significance from receptor value and magnitude of effects was undertaken in accordance with Table 3.8.1 of DMRB LA 104 and is not repeated here. As per DMRB LA 109 and DMRB LA 113, significant effects typically comprise effects that remain within the moderate, large or very large categories once mitigation has been taken into account.

Table 9-1: Soils, Geology, and Groundwater Receptor Values and Descriptions
Receptor Value (Sensitivity) Receptor Description

Very High

Geology

Internationally designated sites of geological value (for example UNESCO World Heritage Sites).

Very High

Soils

Soils directly supporting an EU designated site (for example Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar).

Land Capability for Agriculture (LCA) grade 1 and 2.

Very High

Land Contamination: Human health

Very sensitive land use such as residential or allotments.

Very High

Land Contamination: Groundwater

Groundwater that locally supports a Groundwater Dependent Terrestrial Ecosystem (GWDTE).

Bedrock aquifer with high productivity and Water Framework Directive (WFD) ‘good’ quality status.

Very High

Land Contamination: Surface water

Watercourse classified by the WFD as having ‘good’ overall status.

Site protected under European or UK legislation (for example SAC, SPA, Site of Special Scientific Interest (SSSI).

Very High

Groundwater

Principal bedrock and superficial aquifers. Groundwater flow and yield associated with licensed groundwater abstractions. Groundwater quality associated with SPZ1 (Inner Protection Zone) associated with licensed abstractions.

Buildings of regional or national importance, such as Grade I and II listed buildings, scheduled monuments, hospitals, power stations and large industrial sites.

Water feeding GWDTEs with a high or moderate groundwater dependence with a high environmental importance and international or national value, such as Ramsar sites, SACs, SPAs and SSSIs.

High

Geology

Rare geology and of national importance with little potential for replacement (for example geological SSSI).

High

Soils

Soils directly supporting a UK designated site (for example SSSI).

LCA grade 3.1.

High

Land Contamination: Human health

High sensitivity land use such as public open space.

High

Land Contamination: Groundwater

Bedrock aquifer with moderate productivity and Water Framework Directive (WFD) ‘good’ quality status.

Superficial aquifer where intergranular flow is significant with ‘good’ overall WFD status.

High

Land Contamination: Surface water

Watercourse classified by the WFD as having ‘good’ overall status.

Watercourse protected of regional/local ecological importance.

High

Groundwater

Secondary A aquifers. Groundwater flow and yield and quality associated with extensive non-licensed private water abstractions (for example supplying ten or more properties or supplying large farming / animal estates). Groundwater quality associated with SPZ2 (Outer Protection Zone) associated with licensed abstractions.

Residential and commercial properties and Grade II listed buildings.

Water feeding GWDTEs of low groundwater dependence with a high environmental importance and international or national value, such as Ramsar sites, SACs, SPAs and SSSIs; or water feeding highly or moderately GWDTE with a national non-statutory UK Biodiversity Action Plan (BAP) priority.

Medium

Geology

Geology of regional importance (for example Regionally Important Geological Sites (RIGS)) with limited potential for replacement.

Medium

Soils

LCA grade 3.2.

Medium

Land Contamination: Human health

Medium sensitivity land use such as commercial or industrial.

Medium

Land Contamination: Groundwater

Bedrock aquifer with low productivity and Water Framework Directive (WFD) ‘good’ quality status.

Superficial aquifer where intergranular flow is significant with ‘poor’ overall WFD status.

Medium

Land Contamination: Surface water

Watercourse classified by the WFD as having ‘moderate’ overall status.

Medium

Groundwater

Secondary B and Secondary Undifferentiated aquifers. Groundwater flow and yield and quality associated with small scale private water abstractions (for example feeding fewer than ten properties).

Groundwater quality associated with SPZ3 (Source Catchment Protection Zone) associated with licensed abstractions and with licensed abstractions for which no SPZ is defined.

Unoccupied residential and commercial properties and buildings.

Water feeding GWDTEs of low groundwater dependence with a national non-statutory UK BAP priority; or water feeding highly or moderately groundwater-dependent GWDTE sites with no conservation designation.

Low

Geology

Geology of local importance / interest with potential for replacement (for example non designated geological exposures, former quarries/mining sites).

Low

Soils

LCA grade 4.1 to 7.

Low

Land Contamination: Human health

Low sensitivity land use such as roads and rail.

Low

Land Contamination: Groundwater

Bedrock aquifer with high to low productivity and Water Framework Directive (WFD) ‘poor’ quality status.

Superficial concealed aquifer or aquifer of limited potential with ‘poor’ or ‘good’ overall WFD status.

Low

Land Contamination: Surface water

Watercourse classified by the WFD as having ‘poor’ or ‘bad’ overall status.

Watercourse not classified by the WFD.

Low

Groundwater

Very poor groundwater quality and / or very low permeability make exploitation of groundwater unfeasible. No active groundwater supply.

Industrial buildings that are currently not utilised, all derelict buildings and infrastructure that serves a single dwelling.

Water feeding GWDTE of low groundwater dependence with no designation or groundwater that supports a wetland not classified as a GWDTE, although may receive some minor contribution from groundwater.

Negligible

Geology

No geological exposures, little / no local interest.

Negligible

Soils

Previously developed land formerly in 'hard uses' with little potential to return to agriculture.

Negligible

Land Contamination: Human health

Undeveloped surplus land / no sensitive land use proposed.

Negligible

Land Contamination: Groundwater

Not applicable

Negligible

Land Contamination: Surface water

Not applicable

Negligible

Groundwater

Not applicable
Table 9-2: Soils, Geology, and Groundwater Magnitude of Change and Descriptions
Magnitude of Impact (Change) Receptor Description

Major

Geology

Loss of geological feature / designation and/or quality and integrity, severe damage to key characteristics, features or elements.

Major

Soils

Physical removal or permanent sealing of greater than 20 ha agricultural land.

Major

Land Contamination: Human health

Significant contamination identified. Contamination levels significantly exceed background levels and relevant screening criteria (for example category 4 screening levels) with potential for significant harm to human health. Contamination heavily restricts future use of land.

Major

Land Contamination: Groundwater

Results in loss of attribute and/or quality and integrity of the attribute. Loss of, or extensive change to, an aquifer. Loss of regionally important water supply. Loss of, or extensive change to GWDTE or baseflow contribution to protected surface water bodies. Reduction in water body WFD classification.

Major

Land Contamination: Surface water

Loss or extensive change to a fishery. Loss of regionally important public water supply. Loss or extensive change to a designated nature conservation site. Reduction in water body WFD classification.

Major

Groundwater

Major or irreversible change to groundwater aquifer(s) flow, water level, quality or available yield which endangers the resources currently available. Groundwater resource use/abstraction is irreparably impacted upon, with a major or total loss of an existing supply or supplies.

Changes to water table level or quality would result in a major or total change in, or loss of, a groundwater dependent area, where the value of a site would be severely affected.

Changes to groundwater aquifer(s) flow, water level and quality would result in major changes to groundwater baseflow contributions to surface water and/or alterations in surface water quality, resulting in a major shift away from baseline conditions such as change to WFD status.

Dewatering effects create significant differential settlement effects on existing infrastructure and buildings leading to extensive repairs required.

Moderate

Geology

Partial loss of geological feature/designation, potentially adversely affecting the integrity; partial loss of/damage to key characteristics, features or elements.

Moderate

Soils

Physical removal or permanent sealing of 1 ha – 20 ha of agricultural land or permanent loss / reduction of one or more soil function(s) and restriction to current or approved future use (for example through degradation, compaction, erosion of soil resource).

Moderate

Land Contamination: Human health

Contaminant concentrations exceed background levels and are in line with limits of relevant screening criteria (for example category 4 screening levels). Significant contamination can be present. Control/remediation measures are required to reduce risks to human health/make land suitable for intended use.

Moderate

Land Contamination: Groundwater

Results in effect on integrity of attribute, or loss of part of attribute. Partial loss or change to an aquifer. Degradation of regionally important public water supply or loss of significant commercial/ industrial/ agricultural supplies. Partial loss of the integrity of GWDTE. Contribution to reduction in water body WFD classification.

Moderate

Land Contamination: Surface water

Partial loss in productivity of a fishery. Degradation of regionally important public water supply or loss of major commercial/industrial/agricultural supplies. Contribution to reduction in water body WFD classification.

Moderate

Groundwater

Moderate long term or temporary significant changes to groundwater aquifer(s) flow, water level, quality or available yield which results in moderate long term or temporarily significant decrease in resource availability. Groundwater resource use / abstraction is impacted slightly, but existing supplies remain sustainable. Changes to water table level or groundwater quality would result in partial change in or loss of a groundwater dependent area, where the value of the site would be affected, but not to a major degree.

Changes to groundwater aquifer(s) flow, water level and quality would result in moderate changes to groundwater baseflow contributions to surface water and / or alterations in surface water quality, resulting in a moderate shift from baseline conditions upon which the WFD status rests.

Dewatering effects create moderate differential settlement effects on existing infrastructure and buildings leading to consideration of undertaking minor repairs.

Minor

Geology

Minor measurable change in geological feature / designation attributes, quality or vulnerability. Minor loss of, or alteration to, one (maybe more) key characteristics, features or elements.

Minor

Soils

Temporary loss / reduction of one or more soil function(s) and restriction to current or approved future use (for example through degradation, compaction, erosion of soil resource).

Minor

Land Contamination: Human health

Contaminant concentrations are below relevant screening criteria (for example category 4 screening levels). Significant contamination is unlikely with a low risk to human health. Good practice measures can be used to avoid or reduce risks to human health.

Minor

Land Contamination: Groundwater

Results in some measurable change in attributes, quality or vulnerability. Minor effects on an aquifer, GWDTEs, abstractions and structures.

Minor

Land Contamination: Surface water

Minor effects on water supplies.

Minor

Groundwater

Minor changes to groundwater aquifer(s) flow, water level, quality or available yield leading to a noticeable change, confined largely to the Proposed Programme area.

Changes to water table level, groundwater quality and yield result in little discernible change to existing resource use.

Changes to water table level or groundwater quality would result in minor change to groundwater dependent areas, but where the value of the site would not be affected.

Changes to groundwater aquifer(s) flow, water level and quality would result in minor changes to groundwater baseflow contributions to surface water and / or alterations in surface water quality, resulting in a minor shift from baseline conditions (equivalent to minor but measurable change within WFD status).

Dewatering effects create minor differential settlement effects on existing infrastructure and buildings which may need to be monitored but where repairs may be avoidable.

Negligible

Geology

Very minor loss or detrimental alteration to one or more characteristics, features or elements of geological feature / designation. Overall integrity of resource not affected.

Negligible

Soils

No discernible loss / reduction of soil function(s) that restrict current or approved future use.

Negligible

Land Contamination: Human Health

Contaminant concentrations substantially below levels outlined in relevant screening criteria (for example category 4 screening levels). No requirement for control measures to reduce risks to human health / make land suitable for intended use.

Negligible

Land Contamination: Groundwater

Results in effect on attribute, but of insufficient magnitude to affect the use or integrity. No measurable impact upon an aquifer and/or groundwater receptor.

Negligible

Land Contamination: Surface Water

No measurable impact.

Negligible

Groundwater

Very slight change from groundwater baseline conditions approximating to a ‘no change’ situation. Dewatering effects create no or no noticeable differential settlement effects on existing infrastructure and buildings.

Assessment Adaptations

Full application of the sensitivity and magnitude criteria, particularly in relation to ground conditions and potential contamination, requires a level of detail that is not available at this stage of the proposed scheme. Such information would be obtained through methods such as detailed surveys and intrusive ground investigation.

For DMRB Stage 1 risks from land contamination have been assessed based on a desktop review approach, following guidance set out in Land Contamination Risk Assessment , DMRB LA 109, DMRB LA 113 and DMRB LA 104.

A source risk ranking has been applied to each historical land use identified within the study area (refer to the Potentially Contaminative Land Uses section of this chapter), as defined in Table 9-3 . Note that historical land uses were identified from a number of data sources within the Groundsure report (see Data Sources section of this chapter), and these have been merged to provide a single entry for each potential source.

Table 9-3: Contamination Source Risk Rankings
Source Risk Ranking Risk Description Example Land Uses

3

High risk of potential contamination.

Landfills and waste disposal, tanks, airports, fuel stations.

2

Medium risk of potential contamination.

Brick works, industrial estates and factories, railway land, sewage works.

1

Low risk of potential contamination.

Quarries and pits, ground workings, cuttings, ponds.

0

Unlikely to be a contamination source – scoped out.

Police station, telephone exchange, water tanks.

Assumptions and Limitations

The following limitations apply to this assessment:

  • This assessment is based on six improvement strategies, and as typical for DMRB Stage 1, no detail is available about specific design elements, extent of land take or compound locations for any of the improvement strategies.
  • At this stage of proposed scheme, it is not considered appropriate to undertake a site walkover, and no surveys or site sampling has been undertaken to inform this assessment. A desktop review is considered proportionate and appropriate.
  • A PSSR is currently being undertaken, which will inform the contamination assessment at DMRB Stage 2. Regulator liaison and ground investigation has not yet been undertaken.
  • The purchased Groundsure report covers the majority of the study areas (as defined in the Study Area section of this chapter), although some small areas are not covered. Data gaps have been filled using the third-party data sources defined in the Data Sources section of this chapter.
  • Analysis of consents for discharge to groundwater, which could potentially modify the baseline groundwater chemistry of receiving aquifers, was not considered to be necessary at this stage.
  • Information determining the locations of unlicensed groundwater abstractions has not been obtained and therefore have not been considered at this early stage. These would be assessed once data has been obtained during DMRB Stage 2.
  • GWDTEs are defined as wetlands which critically depend on groundwater flows or chemistry. A full assessment of GWDTE has not been undertaken at this stage. An initial, desk-based screening assessment has been undertaken using publicly available desk-based data such as the Scotland’s Environment Map and brief online descriptions of the site from local authority websites. This will be followed up by field surveys, if required, during later assessment stages.
  • Cultural heritage assets, which may be impacted by subsidence effects, have been identified from a desktop review only. No site survey has taken place and details of foundations have not been obtained. More detailed assessments of cultural heritage assets likely to be impacted by the proposed scheme will be carried out at later assessment stages, if required.

The following assumptions are relevant to this assessment:

  • The geographical extents of the third-party geology and soils baseline information are assumed to be correct.
  • The assessment of potentially contaminative land uses has been undertaken using third-party data. A review of historical maps will be undertaken once a preferred improvement strategy has been selected.
  • Until detailed design information is available, it is assumed that potential impacts on the geology and soils receptors identified in this assessment could occur anywhere within the study area (refer to the Study Area section of this chapter).
  • At this stage of proposed scheme, potential mitigation measures (refer to the Design, Mitigation and Enhancement Measures section of this chapter) have been assumed.

Study Area

For this assessment, ‘improvement strategy’ is the area within which route options may be developed at DMRB Stage 2. The study area applied for the assessments of the different sub-topics throughout this chapter vary.

The study area used for the description of the baseline conditions in relation to human health and controlled waters receptors has been decided in accordance with the conditions presented in DMRB LA109. This has been defined as each improvement strategy plus a 250m buffer in all directions and is shown in Figures 9-1 (A and B) to 9-3. This is in accordance with Guidance for the Safe Development of Housing on Land Affected by Contamination .

For groundwater, a study area of 500m buffer around the assessment corridor has been used and is shown in Figure 9-4 (A and B). For groundwater aspects related to GWDTE, a wider study area of 1km around the assessment corridor has been used due to the sensitivity of the receptor and is shown in Figure 9-4 (C).

This is considered appropriate and proportionate in the context of the proposed scheme, taking account of the distance over which contamination and/or ground gases can migrate.

Baseline Conditions

The following sections outline the baseline soils, geology, land contamination and human health, hydrogeology and hydrology conditions recorded within the study area. A summary of the receptors identified in the study area and the respective sensitivities that have been applied is shown in Table 9-19.

Geology

Superficial Geology

The superficial geology of the study area is summarised in Table 9-4 and shown on Figure 9-1(A).

Table 9-4: Superficial Geology Recorded Within the Study Area
Unit Description Relevant Improvement Strategy

Devensian Till

Diamicton

1, 2, 3, 4, 5, 6

Alluvium

Silt, sand and gravel

1, 2, 3, 4, 5, 6

Glaciofluvial Deposits

Gravel, sand and silt

1, 5, 6

Peat

Peat

1, 2, 5

Bedrock Geology

The bedrock geology of the study area is summarised in Table 9-5 and shown on Figure 9-2.

Table 9-5: Bedrock Geology Recorded within the Study Area
Unit Description Relevant Improvement Strategy

Cairnharrow Formation

Wacke

1, 2, 3

Carghidown Formation

Wacke

1, 2, 3, 4, 5, 6

Kirkmaiden Formation

Wacke

1, 2, 3, 4, 5

North Britain Palaeogene Dyke Suite

Mafite

5

North Britain Siluro-Devonian Calc-alkaline Dyke Suite

Dioritic Rock

1, 2, 6

North Britain Siluro-Devonian Calc-alkaline Dyke Suite

Felsite

1

North Britain Siluro-Devonian Calc-alkaline Dyke Suite

Felsite and Microdioritic Rock

5, 6

North Britain Siluro-Devonian Calc-alkaline Dyke Suite

Lamprophyres

5

North Britain Siluro-Devonian Calc-alkaline Dyke Suite

Microdiorite - Porphyritic

6

Designated Geological Sites

There are no geological Sites of Special Scientific Interest (SSSI), Geological Conservation Review sites or Local Geodiversity Sites in the study area.

Soils

The National scale land capability for agriculture map defines 14 grades of soils according to their suitability for agriculture. Those present in the study area are summarised in Table 9-6.

Table 9-6: Soils Recorded within the Study Area
Soil Grade Description Relevant Improvement Strategy

3.2

Land capable of average production though high yields of barley, oats and grass can be obtained. Grass leys are common.

1, 2, 3, 4, 5, 6

4.1

Land capable of producing a narrow range of crops, primarily grassland with short arable breaks of forage crops and cereal.

1, 2, 3, 4, 5

4.2

Land capable of producing a narrow range of crops, primarily on grassland with short arable breaks of forage crops.

1, 2, 3, 4, 5, 6

5.1

Land capable of use as improved grassland. Few problems with pasture establishment and maintenance and potential high yields.

6

5.2

Land capable of use as improved grassland. Few problems with pasture establishment but may be difficult to maintain.

3, 4, 5, 6

5.3

Land capable of use as improved grassland. Pasture deteriorates quickly.

1, 2, 3, 4, 5, 6

The lengths and estimated maximum footprints of the improvement strategies are listed in Table 9-7. Refer to the Study Area section of this chapter for the definition of the improvement strategy study areas. It should be noted that the improvement strategies are considered a conservative envelope for design, and as such the footprint of any future design is likely to be significantly smaller.

Table 9-7: Comparison of Lengths and Maximum Footprints for each Improvement Strategy
Improvement Strategy Length (km) Area (ha)

1

19

380

2

12.4

248

3

5.4

107

4

6

119

5

11

220

6

17.2

343

Soils Supporting Sites of Ecological Importance

There are no National Nature Reserves, Special Areas of Conservation (SAC) or Ramsar Sites recorded within the study area for soils. Areas of Ancient Woodland are recorded in Improvement Strategies 1, 2 and 3 and the Milton Loch SSSI is located within Improvement Strategy 5.

Potentially Contaminative Land Uses

Table 9-8 summarises the number of potentially contaminative land uses in each risk ranking band for each of the improvement strategies. These are illustrated on Figure 9-3. The risk ranking system is detailed in the Assessment Adaptations section of this chapter.

Table 9-8: Number of Potentially Contaminative Land Uses Recorded within the Study Area
Improvement Strategy Number of High Risk Potentially Contaminative Land Uses Within the Study Area for each Improvement Strategy (3) Number of Medium Risk Potentially Contaminative Land Uses Within the Study Area for each Improvement Strategy (2) Number of Low Risk Potentially Contaminative Land Uses Within the Study Area for each Improvement Strategy (1) Number of Potentially Contaminative Land Uses Within the Study Area for each Improvement Strategy Scoped Out (0) Total Number of Potentially Contaminative Land Uses Within the Study Area for each Improvement Strategy

1

0

0

16

2

18

2

1

0

7

1

9

3

0

4

23

1

28

4

0

1

15

0

16

5

0

0

17

0

17

6

0

1

18

0

19

The key potentially contaminative land uses considered to be medium and high risk within the study area for each improvement strategy is detailed in Table 9-9.

Table 9-9: Key Potentially Contaminative Land Uses Recorded within the Study Area
Improvement Strategy Key Potentially Contaminative Land Uses

1

Not applicable

2

Unspecified tank

3

Garages, unspecified mills

4

Unspecified mill

5

Not applicable

6

Water works / filter station

Human Health Receptors

A range of human health receptors have been identified within the study area, as detailed in Table 9-10.

Table 9-10: Human Health Receptors Recorded within the Study Area
Receptor Description Relevant Improvement Strategy

Residential areas

Springholm, Crocketford

3, 4

Residential areas

Old Bridge of Urr

1

Residential areas

Farmhouses

1, 2, 3, 4, 5, 6

Educational facilities

Springholm Primary School and Springholm Nursery

3, 4

Recreation, public open space

Crocketford Park

1,2

Recreation, public open space

Brandedleys Caravan Park

3, 4

Recreation, public open space

Haugh of Urr Park

6

Commercial and industrial

Farms

1, 2, 3, 4, 5, 6

Transport infrastructure

A75, minor local roads

1, 2, 3, 4, 5, 6

Transport infrastructure

A712

1, 2, 3

Transport infrastructure

B794

1, 5, 6

Transport infrastructure

B795

1

Agricultural / open land

Farmland

1, 2, 3, 4, 5, 6

Groundwater

Further information on hydromorphology and surface waters is presented in the Road Drainage and the Water Environment Chapter of this EAR. The groundwater receptors relevant to this assessment are summarised in this section and shown on Figure 9-4 (A to C).

Aquifer Classifications

Aquifers are water bearing permeable bedrock, or superficial deposits, from which groundwater can be extracted. As discussed in the Groundwater Vulnerability (Scotland) GIS Dataset , the aquifer classification system in Scotland is according to flow type and the aquifers potential for sustaining various levels of borehole water supply. This has been calculated with long term BGS groundwater databases. The classifications are shown in Table 9-11.

Table 9-11: Aquifer Classifications in Scotland
Aquifer Classification Aquifer Productivity

Very High

Greater than 20 L/s

High

10 to 20 L/s

Moderate

1 to 10 L/s

Low

0.1 to 1 L/s

Very Low

Less than 0.1 L/s

The superficial deposits present within the improvement strategies include Alluvium, Peat, Glaciofluvial Deposits, Till (Devensian) and a unit defined by BGS as “Superficial Deposits – Sediment”. The moderately productive alluvium present in the study area coincides with all watercourses identified in the study area. The low productivity Till (Devensian) present in the study area is found on the southern and eastern side of hills, in raised areas throughout the study area. The low productivity Peat present in the study area is found in localised depressions. The moderately productive glaciofluvial deposits present in the study area are flanking the alluvium deposits. The superficial deposits are located under large bodies of surface water like the Milton Loch.

The bedrock present within all improvement strategies is classified as a low productivity aquifer with limited groundwater in near-surface weathered zone and secondary fractures. It is entirely Gneiss from the Hawick group that formed during the Llandovery Epoch. Three formations within the Hawick group have been identified within all six improvement strategies; the Carghidown Formation sits on top of the Kirkmaiden formation that has been thrust over the Cairnharrow formation. There are numerous north-east to south-west trending reverse faults extending from the coast and through Springholm and Crocketford, as well as north-south trending inferred faults displacing various lithologies. There are numerous dyke intrusions within the Carghhidown Gneiss Formation.

The aquifer designations assigned to the bedrock and superficial deposits within the study area are detailed in Table 9-12 and 9-13.

Table 9-12: Aquifer Designations Within the Study Area – Bedrock Geology
Geology Formation Description Distribution Aquifer Designation Groundwater Flow Mechanism Importance Relevant Improvement Strategy

Cairnharrow Formation

Greywacke with interbedded silty mudstone

In west of study area

Low Productivity Aquifer

Flow is virtually all through fractures and other discontinuities

Medium

1, 2, 3

Carghidown Formation

Greywackes with interbedded mudstones

Predominant formation in south-east of study area

Low Productivity Aquifer

Flow is virtually all through fractures and other discontinuities

Medium

1, 2, 3, 4, 5, 6

Kirkmaiden Formation

Greywackes with mudstone interbeds

The A75 is underlain by the Kirkmaiden Formation between Springholm and Crocketford

Low Productivity Aquifer

Flow is virtually all through fractures and other discontinuities

Medium

1, 2, 3, 4, 5

North Britain Siluro-Devonian Calcalkaline Dyke Suite

Mafite, Dioritic Rock, Felsite, Microdioritic rock, Laprophyres and Porphyritic Microdiorite

Found to the south of Improvement Strategy 5

Not Productive

Not applicable

Low

5
Table 9-13: Aquifer Designations Within the Study Area – Superficial Geology
Geology Formation Description Distribution Aquifer Designation Groundwater Flow Mechanism Importance Relevant Improvement Strategy

Devensian Till

Diamicton

Found across the majority of the study area

Low Productivity Aquifer

Inter-granular flow with low permeability

Low

1, 2, 3, 4, 5, 6

Alluvium

Silt sand and gravel

Found near watercourses

Moderate Productivity Aquifer

Intergranular flow, high to low permeability

High

1, 2, 3, 4, 5, 6

Glaciofluvial Deposits

Gravel, sand and silt

Found in the south of the study area surrounding the River Urr

Moderate Productivity Aquifer

Intergranular flow, high to low permeability

High

1, 5, 6

Peat

Peat

Found in small areas in the north of the study area

Un-productive Productivity Aquifer

Typically intergranular flow with low permeability

Low

1, 2, 5

Superficial Deposits

Sediment

Found centrally in the study area

Not applicable

Not applicable

Not applicable

3

According to the Mining Remediation Authority Map Viewer , there are no records of past coal mining within the study area. However, according to the Scottish Cave and Mine Database , there is one record of a mineshaft in the area, called the Old Shaft and located on Ha Hill, south of Springholm.

Drinking Water Safeguard Zones and Licensed Abstractions

Several Drinking Water Safeguard Zones for groundwater are identified within the study area from Scotland's Environment Web Viewer . These include the Galloway (ID: 150694), the Urr Valley (ID: 150769), Castle Douglas (ID: 150672), and Cargenbank (ID: 150542).

Information on private licensed abstractions has not been requested at this time.

Private Unlicensed Abstractions

Private unlicensed abstractions are abstractions of less than 10m 3 /d that do not require SEPA registration. Details of private unlicensed groundwater abstractions have not been requested from the local authorities at this stage. Because there is no obligation for the owner to register private water supplies, unregistered private groundwater supplies may also be present. It is anticipated that this information will be requested to inform later assessment stages.

Fifteen Ordnance Survey (OS) mapped wells have been identified within the improvement strategies, and a further fourteen OS mapped wells have been identified within the 500m study area. The existence of these wells has not been confirmed at the time of writing.

Groundwater-Surface Water Interactions

Groundwater may contribute to the watercourses identified in the Road Drainage and the Water Environment Chapter of this EAR. Groundwater dependence will be reviewed at a later stage.

There are a number of springs, issues, sinks and collects within the study area shown in Table 9-14 . No springs are located within the improvement strategies; however they are present within the wider 500m buffer area.

Table 9-14: Spring Locations
Name of Spring Nearest Improvement Strategy Distance from Nearest Improvement Strategy (m)

East of Cauld Hill

2

368

Northwest of Deanston Loch

5

788

Barr of Spots Dairy House

5

400

West of Markfast

5

1010

East of Midtown of Urr

5

977

East of Gerranton

6

530

North of Rigfoot

6

20

Groundwater Dependent Terrestrial Ecosystems

As discussed in the Biodiversity Chapter of this EAR, there are no Special Protection Areas (SPA), SAC, or Ramsar sites within the improvement strategies associated with the proposed scheme.

There is one potential GWDTE within the 1km study area; Milton Loch SSSI which is partially located within Improvement Strategy 5. It is designated for Beetle Assemblage and Eutrophic Loch status, however the groundwater dependent aspect of this SSSI is likely in reference to the wetland habitats, including wet willow woodland document at the SSSI.

Within the study area, the Milton Loch SSSI has the potential to contain a GWDTE in its freshwater habitats. There is also the Biosphere Reserve, designated west of Crocketford, which may indicate the area contains a protected ecosystem. Additional GWDTEs may be present within the 1km study area and will be reviewed at a later stage.

Surveys and consultation will be undertaken to establish the status and groundwater dependency of non-statutory sites of local value at later stages.

WFD Groundwater Bodies

The WFD Groundwater bodies present within the improvement strategies include Cargenbank (ID: 150542), Castle Douglas (ID: 150672), Galloway (ID: 150694), Urr Water Sand and Gravel (ID: 150769). These groundwater bodies all have a “Good” Quantitative and Qualitative status and are detailed in Table 9-15.

Table 9-15: WFD Groundwater Bodies Recorded within the Study Area
WFD ID and Waterbody Name Relevant Improvement Strategies Overall Status (2023)

150542 Cargenbank

1, 2, 3, 4, 5, 6

Good

150694 Galloway

1, 2, 3, 4, 5, 6

Good

150672 Castle Douglas

5, 6

Good

150769 Urr Water Sand and Gravel

1, 5, 6

Good

Groundwater Vulnerability

No groundwater nitrate vulnerable zones (NVZs) have been designated for this area as shown on the Water Classification Hub .

The groundwater vulnerability class (shown in Table 9-16) of the study area is mostly class 5 with areas of class 4a, likely due to the areas of exposed bedrock outcrop.

Table 9-16: Description of Groundwater Vulnerability Ratings
Groundwater Vulnerability Class Description

5

Vulnerable to most pollutants, with rapid impact in most scenarios.

4b

4 Vulnerable to those pollutants not readily absorbed or transformed

4b More likely to have clay present in the superficial deposits

4a

4 Vulnerable to those pollutants not readily absorbed or transformed

4a May have low permeability soil; less likely to have clay present in superficial deposits

3

Vulnerable to some pollutants; many others significantly attenuated.

2

Vulnerable to some pollutants, but only when they are continuously discharged or leaked.

1

Only vulnerable to conservative pollutants in the long term when continuously and widely discharged/leached

0

Not sufficient data to classify vulnerability: for example below lochs; in urban areas where geological and/or soils data are missing; where superficial deposits are mapped but not classified; or in mined (including opencast) and quarried areas.

Built Environment

Buildings and other structures have the potential to be affected by localised subsidence resulting from dewatering. The study area includes ‘A’ roads and several areas of housing, including Springholm and Crocketford on the existing A75. This assessment also covers potential impacts to listed buildings and other cultural heritage assets resulting from dewatering. The Cultural Heritage Chapter of this EAR covers listed buildings and non-designated historic buildings and scheduled monuments along with any architectural remains that could be affected by the proposed scheme. Sites relevant to this assessment are illustrated on Figure 9-4 (C).

One scheduled monument is present within the 500m study area, this is the Green Island, on the west banks of Loch Milton.

There are multiple identified listed buildings within the improvement strategies as detailed in Cultural Heritage Chapter of this EAR.

Groundwater Quality

Point sources of pollution may have modified the baseline groundwater chemistry of the bedrock and superficial aquifers. Potential sources of pollution are detailed in the Potentially Contaminative Land Uses section of this chapter.

There is no groundwater quality data openly available for this site.

There are no historic or operative landfills in the study area as discussed in the Groundsure report.

Analysis of consents for discharge to groundwater, which could potentially modify the baseline groundwater chemistry of receiving aquifers, has not been considered necessary at this stage therefore this information has not been collected, and no discharge consents are present in the study area.

Summary

The groundwater receptors relevant to this assessment are provided in Table 9-17.

Table 9-17: Groundwater Receptors Within the Study Areas
Receptor Type Receptor Description

Bedrock aquifers

Cairnharrow Formation

Low productivity aquifers are characterised by having a typical yield range of 0.1 to 1 l/s where the aquifer is saturated.

Bedrock aquifers

Carghidown Formation

Low productivity aquifers are characterised by having a typical yield range of 0.1 to 1 l/s where the aquifer is saturated.

Bedrock aquifers

Kirkmaiden Formation

Low productivity aquifers are characterised by having a typical yield range of 0.1 to 1 l/s where the aquifer is saturated.

Superficial aquifers

Devensian Till

Low productivity aquifers are characterised by having a typical yield range of 0.1 to 1 l/s where the aquifer is saturated.

Superficial aquifers

Alluvium

Moderate productivity aquifers are capable of supplying sustainable borehole yields of at least 1 l/s, if it contains sufficient sand and/or gravel, is thick enough and is of large enough extent.

Superficial aquifers

Glaciofluvial Deposits

Moderate productivity aquifers are capable of supplying sustainable borehole yields of at least 1 l/s, if it contains sufficient sand and/or gravel, is thick enough and is of large enough extent.

Superficial aquifers

Peat

Unproductive aquifers are not capable of sustainable water supplies and it is unlikely that there is surface water or wetland ecosystem dependence.

Groundwater abstractions

Licensed Abstractions

Changes to groundwater quality, levels and/or flows could impact private licensed groundwater abstractions

Groundwater abstractions

Private Unlicensed Abstractions

Information on unlicensed groundwater abstractions has not been received at this stage. As abstractions of this type cannot be ruled out, they are included as a potential receptor.

Groundwater-surface water features

Springs

Natural emergences of groundwater at surface. Current and historical OS mapping indicates the presence of springs in the study areas.

Groundwater-surface water features

Wells

A shaft sunk into the ground to collect groundwater. Current and historical OS mapping indicates the presence of wells in the study area

Built environment

Listed buildings

The study area contains several areas of housing around the A75 and 21 listed buildings.

Built environment

Scheduled Monument

Green Island, a scheduled monument located on the western edge of Milton Loch.

Ecological receptors

SSSI

The Milton Loch SSSI has the potential to contain a GWDTE, and there may be more unmapped GWDTEs within the Study Area.

Surface Water

Further information on hydrology is presented in the Road Drainage and the Water Environment Chapter of this EAR. The surface water receptors located within the improvement strategies and the overall status of each water body (where classified) as shown on the Water Classification Hub are summarised in Table 9-18 and shown on Figure 9-4 (A to C).

A small area of the Milton Loch SSSI lies within the footprint of Improvement Strategy 5. This is a shallow eutrophic freshwater loch noted for its beetle assemblages.

Table 9-18: Named Surface Watercourses Recorded within the Study Area
Watercourse Name Relevant Improvement Strategy WFD ID Overall Status (2023)

Barncailzie Lane

3, 4, 5

Not classified under WFD

Not classified under WFD

Bettyknowes Burn

1, 2, 5

10600 Cargen Pow / Bogrie Lane

Moderate ecological potential

Bogrie Lane

1, 2, 6

10600 Cargen Pow / Bogrie Lane

Moderate ecological potential

Brooklands Burn

1, 2, 3

10588 Spottes Burn

Good ecological potential

Causeway Burn

6

Not classified under WFD

Not classified under WFD

Crocketford Burn

1, 2, 3, 4

10600 Cargen Pow / Bogrie Lane

Moderate ecological potential

Cronie Burn

1, 2

Not classified under WFD

Not classified under WFD

Culshan Burn

3, 4, 5

10588 Spottes Burn

Good ecological potential

Deanston Burn

6

10602 Under Brae Lane

Good ecological potential

Garmartin Burn

2, 5

Not classified under WFD

Not classified under WFD

Glenhead Burn

1, 2

Not classified under WFD

Not classified under WFD

Larglea Burn

1, 2, 4, 5

10600 Cargen Pow / Bogrie Lane

Moderate ecological potential

Lochfoot Burn

1, 6

10601 Lochfoot Burn

Moderate ecological potential

Milton Burn

6

10591 Culloch Burn (Milton Loch to Kirkgunzeon Lane)

Good ecological potential

Minnydow Burn

1, 2

Not classified under WFD

Not classified under WFD

Spottes Burn

3, 4, 5, 6

10588 Spottes Burn

Good ecological potential

Under Brae Lane

6

10602 Under Brae Lane

Good ecological potential

Urr Water

1, 5, 6

10583 Urr Water (d/s Drumhumphrey Burn)

Good

Summary of Receptors

A summary of the receptors identified within the relevant study area for each improvement strategy are shown in Table 9-19.

Table 9-19: Summary of Receptors Identified within the Study Areas
Receptor Sensitivity Name Relevant Improvement Strategy 1 Relevant Improve-ment Strategy 2 Relevant Improve-ment Strategy 3 Relevant Improve-ment Strategy 4 Relevant Improve-ment Strategy 5 Relevant Improve-ment Strategy 6

Agricultural soils

Medium

LCA Grade 3.2

Yes

Yes

Yes

Yes

Yes

Yes

Agricultural soils

Low

LCA Grade 4.1 to 7

Yes

Yes

Yes

Yes

Yes

Yes

Human health

Very High

Residential

Yes

Yes

Yes

Yes

Yes

Yes

Human health

High

Educational Facilities

No

No

Yes

Yes

No

No

Human health

High

Recreation, Public Open Space

Yes

Yes

Yes

Yes

No

Yes

Human health

Medium

Commercial and Industrial

Yes

Yes

Yes

Yes

Yes

Yes

Human health

Low

Transport Infrastructure

Yes

Yes

Yes

Yes

Yes

Yes

Groundwater

Medium

Cairnharrow Formation Bedrock Aquifer

Yes

Yes

Yes

No

No

No

Groundwater

Medium

Carghidown Formation Bedrock Aquifer

Yes

Yes

Yes

Yes

Yes

Yes

Groundwater

Medium

Kirkmaiden Formation Bedrock Aquifer

Yes

Yes

Yes

Yes

Yes

No

Groundwater

Medium

Devensian Till Superficial Aquifer

Yes

Yes

Yes

Yes

Yes

Yes

Groundwater

High

Alluvium Superficial Aquifer

Yes

Yes

Yes

Yes

Yes

Yes

Groundwater

High

Glacio-fluvial Deposits Superficial Aquifer

Yes

No

No

No

Yes

Yes

Groundwater

Low

Peat Superficial Aquifer

Yes

Yes

No

No

Yes

No

Groundwater

Very High

Licensed Abstractions

Yes

Yes

Yes

Yes

Yes

Yes

Groundwater

High

Private Unlicensed Abstractions

Yes

Yes

Yes

Yes

Yes

Yes

Groundwater

High

Springs

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

Groundwater

Medium

Wells

Yes

No

Yes

Yes

No

No

Groundwater

High

Listed Buildings

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

Groundwater

Very High

Scheduled Monument

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

None but in wider 500m study area

Groundwater

High

Potential GWDTE (Milton Loch SSSI)

No

No

No

No

Yes

No

Surface water

Very High

Milton Lock SSSI

No

No

No

No

Yes

No

Surface water

High

Brooklands Burn

Yes

Yes

Yes

No

No

No

Surface water

High

Culshan Burn

No

No

Yes

Yes

Yes

No

Surface water

High

Spottes Burn

No

No

Yes

Yes

Yes

Yes

Surface water

High

Deanston Burn, Milton Burn, Under Brae Lane

No

No

No

No

No

Yes

Surface water

Medium

Bettyknowes Burn

Yes

Yes

No

No

Yes

No

Surface water

Medium

Bogrie Lane

Yes

Yes

No

No

No

Yes

Surface water

Medium

Crocketford Burn

Yes

Yes

Yes

Yes

No

No

Surface water

Medium

Larglea Burn

Yes

Yes

No

Yes

Yes

No

Surface water

Medium

Lochfoot Burn

Yes

No

No

No

No

Yes

Surface water

Low

Barncailzie Burn

No

No

Yes

Yes

Yes

No

Surface water

Low

Causeway Burn

No

No

No

No

No

Yes

Surface water

Low

Cronie Burn, Glenhead Burn, Minnydow Burn

Yes

Yes

No

No

No

No

Surface water

Low

Garmartin Burn

No

Yes

No

No

Yes

No

Potential Impacts

Construction

Roads schemes and the associated infrastructure can cause potentially significant effects on geological and soil resources. Construction work for, and operation of, a scheme can also compound environmental effects caused by previous activity. For instance, excavations and groundworks can mobilise contamination that may be present in the ground from former industrial activities.

Following a review of the baseline conditions presented in the Baseline Conditions of this chapter, Table 9-20 provides an overview of the potential impacts that may occur on geology, soil, groundwater and land contamination receptors during construction.

Table 9-20: Potential Impacts on Receptors During Construction of the Proposed Scheme
Element Receptor Potential Impacts

Geology

Designated geological sites

No receptors identified

Soils

Land capable for agriculture

Physical removal or permanent sealing of agricultural land beneath the road footprint. Impact is permanent.

Soils

Land capable for agriculture

Reduction or loss of soil function(s) due to stripping, handling and storage, through mechanisms such as compaction and erosion. Impact may be permanent, or temporary if soils are returned to previous use.

Soils

Peat (superficial geology), and Peatland

Physical removal or sealing of peat deposits beneath the road footprint. Impact is permanent.

Soils

Peat (superficial geology), and Peatland

Potential medium-term disruption of peat deposits due to stripping, handling and storage, through mechanisms such as compaction and erosion. Impact may be permanent, or temporary if soils are returned to previous use.

Soils

Soils supporting sites of ecological importance

No receptors identified

Potential contamination

Human health

Disturbance of contaminated ground could affect construction workers through direct contact with contaminated soils or waters, inhalation or ingestion of contaminated dust or soil particles, or through inhalation of gases or asbestos fibres. Both short and long-term risks could arise.

Potential contamination

Human health

Adjacent land users may be impacted if contamination is disturbed and becomes mobile. Impacts could be via inhalation of contaminated dusts or asbestos, or migration of contaminants or gases within ground or surface waters. Both short and long-term risks could arise.

Potential contamination

Water environment - groundwater

Potential impact to water quality and water resource through mobilisation of contamination and/or creation of pollutant pathways during construction. Potential to further impact surface waters if aquifers are supporting watercourses. Both short and long-term risks could arise.

Potential contamination

Water environment – surface waters

Mobilisation of contamination and/or surface water runoff during construction could lead to potential impact to water quality, ecological potential and/or water resource. Both short and long-term risks could arise.

Groundwater
  • Bedrock Aquifers
  • Superficial Aquifers
  • Licensed abstractions
  • Unlicensed abstractions
  • Potential GWDTE

Potential impacts to groundwater quality due to accidental leaks/spills of fuel and chemicals during construction.

Potential impacts to groundwater quality due to creation of vertical pathways during construction which may result in mobilisation of suspended solids, transport of contaminated groundwater, or mixing of different groundwater chemistries.

Potential impacts to groundwater levels, flows, and/or quality due to excavation of cuttings which may result in dewatering if groundwater is intercepted or compaction due to embankments.

Groundwater

Built environment

Potential increase in risk of groundwater flooding to the built environment.

Operation

During operation, nearby land users could potentially be exposed to contamination if in-ground maintenance works occur in areas where contamination has been left in-situ or could be mobilised to controlled waters. There is also the potential for the proposed scheme to act as a preferential pathway between contamination and controlled waters.

Potential direct impacts on surface water during operation, for example from siltation or spills, are considered within the Road Drainage and the Water Environment Chapter of this EAR.

Potential impacts on groundwater during operation include:

  • Potential impacts to groundwater quality due to contamination from routine runoff which discharges to ground.
  • Potential impacts to groundwater quality due to contamination from accidental leaks/spills which bypass road drainage.
  • Potential impacts to groundwater levels and flows due to permanent below ground structures, which may result in long-term disturbance of groundwater flows.
  • Potential impacts to groundwater quality due to permanent below ground structures which may intercept contaminated groundwater or result in mixing of different groundwater chemistries.
  • Potential impact to groundwater quality, levels and flows due to ongoing dewatering of cuttings via road drainage.
  • Potential increase in risk of groundwater flooding to the built environment.

Design, Mitigation and Enhancement Measures

Mitigation Measures – Construction Phase

Mitigation measures should follow the mitigation hierarchy:

  • Avoidance of effects through design.
  • Minimising effects through limiting the size of the footprint.
  • Reducing the severity of effects through specific mitigation.

Future design mitigation measures could include, but are not limited to, the following:

  • Amendment of the improvement strategy alignment to avoid major constraints, such as a significantly contaminated site.
  • Reduced development footprints to minimise the loss of agricultural land.
  • Stripping of topsoil from the footprints of permanent development, followed by sustainable reuse.

For the purposes of this assessment, it has been assumed that the following would be embedded mitigation:

  • Production of a PSSR to detail the expected ground conditions in the study area.
  • Ground investigation for the preferred improvement strategy, including appropriate sampling for chemical analysis, followed by risk assessment and remediation (if required) in accordance with Land Contamination Risk Management.
  • Ground investigation (including pumping tests if necessary) to assess effects of dewatering and groundwater level monitoring. Further assessment will be undertaken to identify the potential impacts of construction activities and additional mitigation identified, if appropriate, to reduce the significant of any effects.
  • Use of low permeability cut-off walls to control groundwater flows and discharges.
  • Undertake work in line with guidance for pollution prevention and relevant code of construction practices.
  • Ensure that scheme complies with the requirements of SEPA’s approach to Groundwater Protection Policy for Scotland.
  • Minimise the extent of works as far as practicable.
  • Adoption of good soil management practices in accordance with the Construction Code of Practice for the Sustainable Use of Soils on Construction Sites.
  • Development of a Construction Environment Management Plan and Site Waste Management Plan, including robust pollution prevention measures, to reduce the likelihood of the proposed scheme aerating new contamination through leaks and spills during construction.
  • Development of a Materials Management Plan for reuse of materials under The Definition of Waste: Development Industry Code of Practice.
  • Procedures to mitigate risks from encountering unexpected contamination during construction, including control and containment measures.

It should be noted that the potential effects on soils related to land take can only be mitigated through design.

Additional mitigation measures may need to be developed to address identified site-specific impacts. At this early stage in the proposed scheme, the requirement for specific mitigation measures cannot be meaningfully identified, particularly in relation to impacts related to ground contamination. Any potential remediation requirements are usually informed by ground investigation, detailed risk assessment and the development of a Conceptual Site Model. Potential mitigation solutions and remediation costs are likely to be more complex if the proposed scheme is aligned through higher risk areas, and as such the design should avoid these areas if possible.

Mitigation Measures – Operational Phase

At the time of writing, it is not expected that mitigation will be required during the operational phase, as any contamination present in areas where maintenance works may occur shall be dealt with during construction.

Mitigation that may be required during the operational phase to reduce impact to groundwater receptors includes the following:

  • Foundations and other potential below ground structures should be designed to allow existing groundwater flow paths to function to prevent an increase in groundwater flood risk and to protect nearby sensitive receptors, such as issues/springs.
  • If impacts occur from abstracting groundwater to keep cuttings dry, then use abstracted water to recharge groundwater.
  • Avoid routes which pass through or close to the most sensitive areas for example Milton Loch SSSI, and areas where groundwater contributes to other ecological receptors.
  • Install pollution prevention measures for drainage systems using industry-established treatment trains.
  • Locate drainage discharge points to ground and groundwater outside of the most sensitive areas such as the Milton Loch SSSI and other areas where groundwater contributes to ecological receptors.

Enhancement Measures

At the time of writing, no enhancement measures have been identified for the construction or operational phases. There is the potential for enhancement opportunities to be identified during later stages of the proposed scheme. Examples of such opportunities may include improving existing or creating new geological exposures, remediation measures and/or the collection and analysis of geological data.

Assessment of Likely Significant Effects

The following sections outline the anticipated significant effects that are predicted to occur as a result of the development of the proposed scheme. Significant effects are defined as those assessed as moderate and above. Non-significant effects (slight and neutral) have not been included.

Construction Phase

Soils

The significance of potential effects on soils is summarised in Table 9-21. It should be noted that at this stage of the proposed scheme, no specific detail relating to required land take has been determined. As such, the extents of land take are expected to be significantly overestimated at this stage. However, Improvement Strategies 3 and 4 are likely to have lower impacts on soils through disturbance and sealing because they cover the least total area.

In addition, areas or extents of temporary land-take such as access tracks or compounds, are currently unknown.

Table 9-21: Potentially Significant Construction Effects on Soils
Effect Receptor Sensitivity Relevant Improvement Strategies Magnitude of Impact Significance

Physical removal or permanent sealing of agricultural land/peat beneath the road footprint

LCA Grade 3.2

Medium

1, 2, 5, 6

Major

Large

Physical removal or permanent sealing of agricultural land/peat beneath the road footprint

LCA Grade 4.1 to 7

Low

1, 2, 5, 6

Major

Moderate

Physical removal or permanent sealing of agricultural land/peat beneath the road footprint

LCA Grade 3.2

Medium

3, 4

Moderate

Moderate

Physical removal or permanent sealing of agricultural land/peat beneath the road footprint

Peat (superficial geology), and Peatland (class 3, 4 and 5)

High

All

Major

Large

Reduction or loss of soil function(s) due to stripping, handling and storage, through mechanisms such as compaction and erosion.

Peat (superficial geology), and Peatland (class 3, 4 and 5)

High

All

Major

Large

Human Health

The types of human health receptors potentially affected by the realisation of potential contaminant linkages during construction are broadly comparable between the improvement strategies, with the exception of educational facilities, recreational facilities and public open space. However, no significant effects for human health have been recorded.

Groundwater

The types and sensitivities of hydrogeological receptors potentially affected during construction are broadly comparable between the improvement strategies. However, with the improvement strategies that cover a greater land area there is a greater area of aquifer that has the potential to be affected.

Table 9-22: Potentially Significant Construction Effects on Groundwater
Effect Receptor Sensitivity Relevant Improvement Strategies Magnitude of Impact Significance

Pollution of groundwater quality due to mobilisation of contamination and/or creation of pollutant pathways

Licensed abstractions

Very High

All

Minor

Moderate

Pollution of groundwater quality due to accidental leaks/spills of fuel and chemicals

Licensed abstractions

Very High

All

Minor

Moderate

Quantitative impact to groundwater levels, flows, and/or quality due to excavation of cuttings which may result in dewatering if groundwater is intercepted or compaction due to embankments.

Licensed abstractions

Very High

All

Minor

Moderate

Surface Water

Generally, the improvement strategies that cover a larger area intersect with a greater number of surface watercourses, and as such the potential for effects to be realised is greater.

Table 9-23: Potentially Significant Construction Effects on Surface Water
Effect Receptor Sensitivity Relevant Improvement Strategy Magnitude of Impact Significance

Mobilisation of contamination and/or surface water runoff during construction

Milton Loch SSSI

Very High

5

Minor

Moderate

Operation Phase

Following the construction mitigation measures outlined in the Design, Mitigation and Enhancement Measures section of this chapter, no significant operational effects are likely to arise.

Proposed Scope of Future Assessment

A PSSR is being produced for the study area, including a preliminary Conceptual Site Model (CSM). This will inform on the likely ground conditions for the improvement strategies, and feed into the designing of an appropriate ground investigation strategy, including environmental sampling and assessment. Results from the ground investigation should be assessed against appropriate criteria and will feed into the development of the land contamination risk assessment and CSM revision within the Ground Investigation Report.

At DMRB Stage 2, an Environmental Scoping Report and Environmental Assessment Report shall be produced. These reports will expand on the assessment of the potential impacts to the receptors outlined in this chapter.

Summary

A range of baseline data has been reviewed and used to identify relevant geology, soils and groundwater receptors in the study areas. The receptors identified for the improvement strategies are agricultural soils, human health, groundwater and surface waters.

In accordance with relevant industry guidance, an assessment was undertaken on the potential effects on these receptors from the implementation of the proposed scheme and their potential significance. The following significant effects were identified for all improvement strategies unless otherwise stated:

  • Physical removal or permanent sealing of agricultural land and/or peat.
  • Reduction or loss of soil function(s) due to stripping, handling and storage, through mechanisms such as compaction or erosion.
  • Potential mobilisation of contamination and/or surface water runoff into Milton Loch SSSI (Improvement Strategy 5 only).
  • Spills and leaks of construction runoff could impact groundwater quality.
  • Routine road runoff discharge or spills and leaks increase the risk of pollution.

In conclusion, potential significant effects were similarly identified across all improvement strategies. With the exception of Improvement Strategy 5 where additional potential significant effects were identified for surface water due to its proximity to Milton Loch SSSI.

The risk of potential significant effects being realised is highest for Improvement Strategies 1 and 6 as they cover the greatest total area. Improvement Strategy 5 is the next most likely to have significant effects due to its length and proximity to Milton Loch SSSI, followed by Improvement Strategy 2, then Improvement Strategy 4 and 3 due to their smaller total areas.

The identified effects on soils are due to land take and would need to be mitigated through route optioneering or future design mitigation measures.