8 Water Environment 8.1 Introduction 8.2 Approach and Methods 8.3 Baseline Conditions 8.4 Potential Impacts 8.5 Potential Mitigation 8.6 Summary of Route Corridor Options Assessment 8.7 Scope of Stage 3 Assessment 8.8 References

8 Water Environment

8.1 Introduction

8.1.1 This chapter presents the assessment of the Stage 2 route corridor options for the Forth Replacement Crossing in terms of water quality, hydrology, flood risk and fluvial and coastal geomorphology. The assessment methodologies are explained, including details of the main sources of information that were utilised.

8.1.2 The baseline conditions are described, representing the existing or ‘do minimum scenario’ which is the situation if the proposed Forth Replacement Crossing were not to proceed.

8.1.3 Potential impacts that may occur as a consequence of the different route corridor options are considered and compared. Potential impacts of the northern and southern route corridor options are considered separately. As the bridge is considered to be a ‘given’ for all route corridor options, potential impacts are assessed in isolation.

8.1.4 Types of mitigation to avoid, reduce or offset the potential impacts are outlined where possible, based on guidance and best practice. In conclusion, there is a summary of the options assessment, which identifies the preferred combination of north and south options from the perspective of protecting the water environment.

8.2 Approach and Methods

8.2.1 This chapter considers and assesses impacts to the surface water environment: hydrology / flood risk; fluvial and coastal geomorphology; and water quality, as outlined below:

Hydrology and Flood Risk: the assessment of potential impacts on the water flow on or near the land surface, which is intrinsically linked to hydrogeology, water quality, geomorphology and ecology.
Fluvial and Coastal Geomorphology: the assessment of landforms associated with river channels and estuaries and the sediment transport processes which form them. Fluvial and coastal processes create a wide range of morphological forms which provide a variety of habitats within and around river / estuarine channels and shorelines.
Water Quality: the assessment of the chemical status of various parameters within the water column and their interactions.

8.2.2 As indicated above, this chapter specifically addresses fluvial and coastal geomorphology; geomorphology in the context of solid and drift geology is considered separately in Chapter 7 (Geology, Contaminated Land and Groundwater). While the relevant fisheries designations have been considered in this chapter, potential impacts on freshwater ecology are considered within Chapter 9 (Ecology and Nature Conservation).

8.2.3 The study area including water features and associated water catchments, are shown on Figures 8.1 and 8.2.

Baseline Conditions

8.2.4 Baseline conditions were identified through a combination of consultation, desk-based assessment and site walkovers.

8.2.5 Data were collated from the following sources:

Ordnance Survey Maps;
Flood Estimation Handbook (FEH) Version 2 (Institute of Hydrology, 2007);
Centre for Ecology and Hydrology (CEH) CD-Rom;
SEPA indicative flood maps (www.sepa.org.uk/flooding/mapping/index); and
SEPA water quality monitoring data and designated fisheries information.

8.2.6 Walkover surveys of the study area were undertaken in April and May 2008 to visually inspect watercourses and surface water bodies in order to gain an understanding of the local topography, hydrological regime, sediment processes and characteristics of the water environment.

8.2.7 The water quality assessment was conducted using data from SEPA’s website and water chemistry spot sampling undertaken at strategic locations along minor watercourses not monitored by SEPA. These spot samples were undertaken in April and early May 2008, and were used in this assessment to give an indication of the water chemistry of watercourses not monitored by SEPA.

8.2.8 The SEPA flood map provides a Scotland-wide picture of the areas at risk of flooding from rivers and the sea by providing a flood outline for areas estimated to be at risk if there were no flood defences. Flood defences do not completely remove the chance of flooding and can be overtopped or fail in extreme weather conditions. The web version shows an estimate of the areas of Scotland with a 0.5% (1:200) or greater probability of being flooded in any given year.

8.2.9 The SEPA indicative flood maps do not provide sufficient detail to accurately estimate the flood risk associated with individual properties or specific point locations. Local factors such as flood defence schemes, structures in or around river channels such as bridges, buildings and other local influences, which might affect a flood, have not been included. The flood map does not account for flooding from other sources such as surface water runoff, surcharged culverts (where watercourses have been channelled underground) or drainage systems. It is based on a digital terrain model with a vertical accuracy in the range 0.7m – 1.0m, on a grid spacing of 5m. It is not relevant to catchments below 3km².

8.2.10 Catchment areas were determined using the FEH methodology and as such are therefore indicative. Time to peak flows estimated from the FEH indicate that the catchments within the survey area are low to moderate relief.

8.2.11 The 2000/60/EC ‘Water Framework Directive’ aims to classify surface waters according to their ecological status and sets targets for restoring / improving the ecological status of water bodies. The Water Environment (Controlled Activities) (Scotland) Regulations 2005 (CAR) have been introduced (hereafter referred to as CAR) in response to the requirements of the Water Framework Directive (WFD). Under CAR, Environmental Standards for River Morphology have been established (SEPA, 2007b). These standards are used to determine whether the impact of an engineering activity would result in a deterioration in WFD status by establishing ‘capacity limits’ for future channel modification. As these tests are conducted by SEPA during the CAR application process it is not possible, nor is it a requirement, to apply this methodology at the DMRB Stage 2 assessment. However, the impact magnitude methodology adopted here, which is based on the extent of watercourse engineering activity, does provide a compatible options screening methodology.

8.2.12 As DMRB does not outline a specific methodology to enable the geomorphological impacts to be evaluated, the methodology adopted in this appraisal was developed using the guidelines from Research and Development Programmes of the National Rivers Authority, Environment Agency and SNH (Environment Agency, 1998; Sear et al., 2003). This chapter addresses geomorphology with regard to potential effects on water features, with geomorphology in the context of solid and drift geology considered separately in Chapter 7 (Geology, Contaminated Land and Groundwater).

Impact Assessment

8.2.13 The impact assessment has been carried out using the general approach outlined below, where the level of significance of an impact is assessed based on the sensitivity of the surface water feature and the magnitude of impact.

Sensitivity

8.2.14 The sensitivity of the receiving environment was categorised on a scale of ‘Low’ to ‘High’, in accordance with the criteria provided in Table 8.1. Impacts are adverse unless stated otherwise.

Table 8.1: Criteria to Assess the Sensitivity of Water Features

Sensitivity	Criteria
High	Hydrology and Flood Risk: A watercourse with direct flood risk to the adjacent populated areas, critical social infrastructure units such as hospitals, schools, safe shelters or land use of great value. Active floodplain area. A watercourse / hydrological feature with hydrological importance to: i) sensitive and protected ecosystems; ii) critical economic and social uses (e.g. water supply, navigation, recreation, amenity etc.). A watercourse / floodplain / hydrological feature that provides critical flood alleviation benefits or any property that is at risk of flooding due to the proposed road scheme. Fluvial and Coastal Geomorphology: A watercourse supporting a range of species and habitats sensitive to a change in suspended sediment concentrations and turbidity such as migratory salmon or freshwater pearl mussels. Includes sites with international and UK statutory nature conservation designations due to water-dependent ecosystems. Diverse channel / shoreline morphology, including many natural features such as pools and riffles, active gravel bars, free meandering and varied shoreline / river bank types with good vegetation cover. Such morphological variability is a primary determinant of ecological diversity. High likelihood of adverse morphological adjustment, such as excessive erosion and sediment deposition, as a direct result of engineering activities such as bank protection, culverting and realignment (due to high channel or valley gradient or bed and bank composition). Water Quality: Receptor is of high environmental importance or of national or international value. For example, a large or medium-sized watercourse with pristine or near pristine water quality (SEPA water quality A1 (excellent)). Nature conservation designation due to water-dependent ecosystems (including Special Protection Area (SPA), Special Area of Conservation (SAC) and Site of Special Scientific Interest (SSSI),), or designated for freshwater ecological interest (designated salmonid fishery).
Medium	Hydrology and Flood Risk: A watercourse with a possibility of direct flood risk to less populated areas without any critical social infrastructure units such as hospitals, schools, safe shelters and / or utilisable agricultural fields. A watercourse / hydrological feature with some but limited hydrological importance to: i) sensitive or protected ecosystems; ii) economic and social uses (e.g. water supply, navigation, recreation, amenity etc). A watercourse / floodplain / hydrological feature that provides some flood alleviation benefits. Fluvial and Coastal Geomorphology: A watercourse supporting some species and habitats sensitive to a change in suspended sediment concentrations and turbidity. Includes non-statutory sites of regional or local importance designated for water-dependent ecosystems. Moderate morphological diversity. Evidence of localised engineering modification such as bank / shoreline protection, but natural features such as intertidal flats, pools and riffles are present. Potential for morphological adjustment, such as erosion and sediment deposition, as direct result of engineering activities such as bank protection, culverting and realignment (due to gradient or bed and bank composition), but which would have limited environmental impact. Water Quality: Receptor is of medium environmental importance or of local / regional value. For example SEPA water quality A2 (good) or B (fair), designated cyprinid fishery, salmonid species may be present and catchment locally important for fisheries.
Low	Hydrology and Flood Risk: A watercourse passing through uncultivated agricultural land. A watercourse with minimal hydrological importance to: i) sensitive or protected ecosystems; ii) economic and social uses (e.g. water supply, navigation, recreation, amenity etc.). A watercourse / floodplain / hydrological feature that provides minimal flood alleviation benefits. Fluvial and Coastal Geomorphology: A watercourse which does not support any significant species sensitive to changes in suspended solids concentration or turbidity. Watercourses exhibiting no morphological diversity; flow is uniform, bars are absent and bank / shoreline types uniform and stable. Evidence of widespread engineering modification such as sea defence, realignment and deepening. Very limited potential for morphological adjustment, such as erosion and sediment deposition, as direct result of engineering activities such as bank protection, culverting and realignment (due to low gradient or resistant bed and bank composition). Water Quality: Receptor is of low environmental importance. For example SEPA water quality B (fair), C (poor) or D (seriously polluted) and fish sporadically present or restricted, no designated fisheries.

Sensitivity

Criteria

High

Hydrology and Flood Risk: A watercourse with direct flood risk to the adjacent populated areas, critical social infrastructure units such as hospitals, schools, safe shelters or land use of great value. Active floodplain area. A watercourse / hydrological feature with hydrological importance to: i) sensitive and protected ecosystems; ii) critical economic and social uses (e.g. water supply, navigation, recreation, amenity etc.). A watercourse / floodplain / hydrological feature that provides critical flood alleviation benefits or any property that is at risk of flooding due to the proposed road scheme.

Fluvial and Coastal Geomorphology: A watercourse supporting a range of species and habitats sensitive to a change in suspended sediment concentrations and turbidity such as migratory salmon or freshwater pearl mussels. Includes sites with international and UK statutory nature conservation designations due to water-dependent ecosystems.

Diverse channel / shoreline morphology, including many natural features such as pools and riffles, active gravel bars, free meandering and varied shoreline / river bank types with good vegetation cover. Such morphological variability is a primary determinant of ecological diversity.

High likelihood of adverse morphological adjustment, such as excessive erosion and sediment deposition, as a direct result of engineering activities such as bank protection, culverting and realignment (due to high channel or valley gradient or bed and bank composition).

Water Quality: Receptor is of high environmental importance or of national or international value. For example, a large or medium-sized watercourse with pristine or near pristine water quality (SEPA water quality A1 (excellent)). Nature conservation designation due to water-dependent ecosystems (including Special Protection Area (SPA), Special Area of Conservation (SAC) and Site of Special Scientific Interest (SSSI),), or designated for freshwater ecological interest (designated salmonid fishery).

Medium

Hydrology and Flood Risk: A watercourse with a possibility of direct flood risk to less populated areas without any critical social infrastructure units such as hospitals, schools, safe shelters and / or utilisable agricultural fields. A watercourse / hydrological feature with some but limited hydrological importance to: i) sensitive or protected ecosystems; ii) economic and social uses (e.g. water supply, navigation, recreation, amenity etc). A watercourse / floodplain / hydrological feature that provides some flood alleviation benefits.

Fluvial and Coastal Geomorphology: A watercourse supporting some species and habitats sensitive to a change in suspended sediment concentrations and turbidity. Includes non-statutory sites of regional or local importance designated for water-dependent ecosystems.

Moderate morphological diversity. Evidence of localised engineering modification such as bank / shoreline protection, but natural features such as intertidal flats, pools and riffles are present.

Potential for morphological adjustment, such as erosion and sediment deposition, as direct result of engineering activities such as bank protection, culverting and realignment (due to gradient or bed and bank composition), but which would have limited environmental impact.

Water Quality: Receptor is of medium environmental importance or of local / regional value. For example SEPA water quality A2 (good) or B (fair), designated cyprinid fishery, salmonid species may be present and catchment locally important for fisheries.

Low

Hydrology and Flood Risk: A watercourse passing through uncultivated agricultural land. A watercourse with minimal hydrological importance to: i) sensitive or protected ecosystems; ii) economic and social uses (e.g. water supply, navigation, recreation, amenity etc.). A watercourse / floodplain / hydrological feature that provides minimal flood alleviation benefits.

Fluvial and Coastal Geomorphology: A watercourse which does not support any significant species sensitive to changes in suspended solids concentration or turbidity.

Watercourses exhibiting no morphological diversity; flow is uniform, bars are absent and bank / shoreline types uniform and stable. Evidence of widespread engineering modification such as sea defence, realignment and deepening.

Very limited potential for morphological adjustment, such as erosion and sediment deposition, as direct result of engineering activities such as bank protection, culverting and realignment (due to low gradient or resistant bed and bank composition).

Water Quality: Receptor is of low environmental importance. For example SEPA water quality B (fair), C (poor) or D (seriously polluted) and fish sporadically present or restricted, no designated fisheries.

Impact Magnitude

8.2.15 The magnitude is influenced by the timing, scale, size and duration of the potential effect, as defined in Table 8.2.

8.2.16 It should be noted that some of the criteria listed in Table 8.2 are to a level of detail beyond the scope of a DMRB Stage 2 assessment and assessment of magnitude has been made on the basis of currently available information regarding engineering design. However the criteria will also form the basis for assessment at Stage 3 which will enable refinement of the assessments using these detailed criteria.

Table 8.2: Criteria to Assess the Magnitude of the Predicted Impact on Water Features

Magnitude	Criteria
High	Hydrology and Flood Risk: Major changes to the flow regime (low, mean and / or high flows – at the site, upstream and / or downstream). An alteration to a catchment area in excess of a 25% reduction or increase in area. Significant increase in the extent of "medium to high risk" areas (classified by the Risk Framework of Scottish Planning Policy Guidance 7 (SPP7)). This means there would be significantly more areas / properties at risk from flooding by the 0.5% (1 in 200 year) or greater annual exceedance probability (AEP). Fluvial and Coastal Geomorphology: More than one new watercourse crossing will be required. This will increase both the extent of watercourse engineering in the catchment and lead to at least four transitions between new sections of engineered watercourse and the existing channel. These transitions can alter the nature of fluvial processes (paragraphs 8.2.18 and 8.2.19). Water Quality: Major shift away from the baseline conditions, fundamental change to water quality condition either by a relatively high amount for a long-term period or by a very high amount for an episode such that watercourse ecology is greatly changed from the baseline situation. Equivalent to downgrading from Class A to C or D, or from B to D or any change that downgrades a site from good status as this does not comply with the Water Framework Directive.
Medium	Hydrology and Flood Risk: Moderate shift away from baseline conditions and moderate changes to the flow regime. An alteration to a catchment area in excess of 10% but less than 25%. Moderate increase in the extent of "medium to high risk" areas (SPP7). Fluvial Geomorphology: A single additional watercourse crossing will be required. This will increase the extent of watercourse engineering in the catchment and require two transitions between the section of engineered watercourse and the existing channel. These transitions can alter the nature of fluvial processes (paragraphs 8.2.18 and 8.2.19). Water Quality: A moderate shift from the baseline conditions that may be long-term or temporary. Results in a change in the ecological status of the watercourse. Equivalent to downgrading one class, for example from C to D.
Low	Hydrology and Flood Risk: Minimum changes to the flow regime. An alteration to a catchment area in excess of 1% but less than 10%. Slight increase in the extent of "medium to high risk" areas (SPP7). Fluvial and Coastal Geomorphology: Upgrade to, or extension of, existing watercourse crossing. This will result in a less substantial deviation from baseline conditions than adding an entirely new section of watercourse. Water Quality: Minor shift away from the baseline conditions. Changes in water quality are likely to be relatively small, or be of a minor temporary nature such that watercourse ecology is slightly affected. Equivalent to minor but measurable change within a class.
Negligible	Hydrology and Flood Risk: Negligible changes to the flow regime (i.e. changes that are within the monitoring errors). An alteration to a catchment area of less than 1% reduction or increase in area. Negligible change in the extent of "medium to high risk" areas (SPP7). Fluvial and Coastal Geomorphology: No direct engineering impact but potential indirect impact due to proximity of watercourse to road corridor, such as pollution by sediment release. Water Quality: Very slight change from the baseline conditions such that no discernible effect upon the watercourse ecology results. No change in classification.

Impact Significance

8.2.17 The significance of impact was determined as a function of the sensitivity of the receiving environment and the magnitude of the impact, as outlined in Table 8.3.

Table 8.3: Significance of Impact

Magnitude / Sensitivity	Negligible	Low	Medium	High
High	Negligible	Moderate	Moderate / Substantial	Substantial
Medium	Negligible	Slight	Moderate	Moderate / Substantial
Low	Negligible	Negligible	Slight	Moderate

8.2.18 The impacts on the geomorphology of the watercourse were assessed using information available at the time of the assessment. This information consisted of the location of proposed crossings but did not include specific information regarding the type of crossing structure or the extent of the impact on the watercourse. The nature and extent of impacts on watercourse geomorphology are influenced by the extent of earthworks required, the type of crossing structure chosen and the need for watercourse realignment which are themselves influenced by topography, existing watercourse geometry and carriageway width. For this reason the assessment was based on the number of potential crossings and whether this involved modification to existing watercourse crossings or construction of entirely new crossing structures.

8.2.19 Although a single large new crossing structure could affect a greater extent of the watercourse than two new small crossing structures, this does not necessarily mean it would have a greater impact on the watercourse. The transitions between the existing watercourse and new sections of channel engineering (such as realignments or culverts) represent locations where geomorphological impacts are likely to be greatest. In the context of the WFD, activities which will increase the extent of modifications to watercourses or lead to potential threats to the status of a water body are undesirable and may potentially be rejected by SEPA during the CAR application process. Therefore, extensive areas of new watercourse engineering can have a high impact on the water environment irrespective of the existing degree of watercourse engineering.

Limitations to Assessment

8.2.20 There are certain limitations within each discipline with regards to the assessment methodologies, which resulted in a number of assumptions being made in the baseline assessment as set out in the following paragraphs. It should be noted, however, that this Stage 2 assessment is considered robust and that such limitations to assessment are considered normal at this stage.

8.2.21 At this stage, road route and junction options are known in plan, with some indication of proposed longitudinal profiles. Apart from the proposed replacement bridge over the Firth of Forth, no specific proposals regarding crossing structure type are available. Details of watercourse engineering, construction activities and road drainage networks are not available at this stage. As the assessment of the magnitude of impact can only be based on available information; this is based on whether existing structures would be modified or whether new structures would be required and the number of such changes proposed on each watercourse.

Hydrology and Flood Risk

8.2.22 No hydrometric data were available for the water features considered in the hydrology assessment, i.e. the watercourses are ungauged. Although suitable methodologies have been applied to these ungauged catchments, the absence of site specific monitoring data inevitably means that larger uncertainties must be attached to these estimates.

Fluvial and Coastal Geomorphology

8.2.23 The approach adopted in this Stage 2 assessment has classified the sensitivity of watercourses taking account of the degree of existing modifications to watercourses (Table 8.1) in accordance with Environment Agency guidance (Environment Agency, 1998, p 15). However, this sensitivity scoring may not necessarily be compatible with the goals of the WFD as watercourses that are already modified by human activities may be at risk of failing their WFD targets making them sensitive to further engineering.

8.2.24 The baseline conditions were judged on field observations recorded during a single site visit. This provides an indication of character at a snap-shot of time rather than over a longer temporal period. As a result, the watercourses were observed under one flow condition (often low flow) rather than under several flow conditions, and therefore may not have accurately reflected average flow conditions and the dynamics of the watercourse. Similarly the density of riparian and channel vegetation along watercourses, which varies seasonally, was recorded within a single season (late spring). Vegetation can obscure sections of channel erosion giving a potentially misleading impression of channel stability.

Water Quality

8.2.25 Spot sampling results provide only a snapshot of the water chemistry conditions in the watercourse at the time the sample was obtained. These results are not considered to be the equivalent of monitoring data and do not provide information in regards to the long-term water quality of the watercourse. Consequently, where watercourses are not classified by SEPA, a judgement has been made as to their quality and sensitivity, based on site visit observations, surrounding land use and designations besides the use of spot sampling data.

8.2.26 No information on abstractions was available at the time of assessment. It is however possible that there are surface water abstractions in the area and these will be identified during ongoing consultation during Stage 3 assessment.

8.3 Baseline Conditions

Introduction

8.3.1 The locations of the water features in the study area are shown on Figure 8.1, water catchments on Figure 8.2 and areas of flood risk on Figure 8.3

8.3.2 Table 8.4 below describes the baseline situation for all water features potentially impacted by the proposed scheme options. The baseline conditions generally reflect the ‘Do Minimum Scenario’, which is based on an assumption of no Forth Replacement Crossing and continued use of the Forth Road Bridge and associated road infrastructure.

8.3.3 SEPA has no records of surface water abstractions in the study area (refer to paragraph 8.2.26). Groundwater abstractions are considered separately in Chapter 7 (Geology, Contaminated Land and Groundwater).

Table 8.4: Baseline Conditions

Water Feature	SEPA Class	Baseline description	Sensitivity
Firth of Forth	B (Good)	Hydrology and Flood Risk: The coastline in the survey area is shown by SEPA to be at risk of flooding from the sea on both the North and South shores of the Firth of Forth. Coastal Geomorphology: The Firth of Forth is an important estuarine water resource and is of international ecological importance (Firth of Forth SSSI, SPA, and Ramsar) providing habitat (intertidal flat, saltmarsh and rocky shores) for waterfowl and waders. The shoreline in the immediate vicinity of the proposed crossing is also designated as SSSI for its geomorphological and geological value. The proposed crossing is within the Lower Firth of Forth Transitional Water Body (ID 200435) in the Scotland River Basin District as classified by SEPA (2008). Its typology is defined as partly mixed / stratified, mesohaline / polyhaline, strongly mesotidal and sheltered. The water body is identified as WFD risk status: 2a not at risk (probably). It is not considered as a whole to be heavily modified. Identified morphological alteration pressures include dredging (resulting in sediment removal) and land reclamation. Immediately to the west of the proposed crossing on the north bank of the Firth of Forth is the St Margaret’s Marsh SSSI. This 26.4 hectares of coastal habitat supports an extensive area of coastal reedbed, saltmarsh, tall herb vegetation and scrub. The morphology of the shoreline of the Firth of Forth is heavily modified by engineering structures including the protruding walls and associated infrastructure of the Port of Rosyth (North Shore) and Port Edgar (South Shore); land claim and sea defence structures at North Queensferry and St Margaret’s Marsh (North Shore) and South Queensferry (South Shore); engineered bridge structures relating to the Forth Road Bridge and Forth Rail Bridge affect both the North and South shorelines of the Firth of Forth, as well as the in-channel morphology. Water Quality: The Firth of Forth including the waters surrounding the proposed bridge crossing is classified under the SEPA estuarine water quality classification system as Class B (Good). Considered to receive anthropogenic pressure from sewage, industrial and road drainage discharges. However, areas of the estuary are of high environmental importance with areas of water-dependent ecosystems designated as SPA, Ramsar sites and SSSIs.	Hydrology / Flood Risk: High Geomorphology: High Water Quality: High
Northern Study Area
Balbougie Burn (1.5 km² catchment)	Unclassified	Hydrology and Flood Risk: Flooding is not currently indicated by SEPA for this tributary. Fluvial Geomorphology: This gravel-bedded stream is a tributary of Keithing Burn, approximately 3.5 km in length. For the majority of its length the burn is set within a steep-sided wooded v-shaped valley. Within the wooded gorge the channel has a sinuous planform with varied channel morphology. However, the watercourse is extensively culverted in its middle reaches where it passes under the M90 and B981 roads. Where the watercourse is located in an area of farmland (upper and lower reaches) the channel is straighter and more uniform in character and appears to reflect past channel modification. Evidence of localised engineering modification principally in the form of culverting and occasional bank protection. Water Quality: Not classified under SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from agriculture and road drainage. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology/ Flood Risk: Low Geomorphology: Medium Water Quality: Low
Pinkerton Burn (2.58km² catchment)	Unclassified	Hydrology and Flood Risk: shown by SEPA not to be at risk of flooding upstream of the confluence with the Keithing Burn. Fluvial Geomorphology: Pinkerton Burn is a tributary of Keithing Burn. This gravel-bed stream is approximately 2.5 km long. In its upper reaches, the catchment is dominated by recently constructed housing estates built on former farmland. Here the watercourse appears to have been subject to channel modifications in the form of localised realignment. In its middle reaches the watercourse is located in a steep-sided v-shaped gorge-like valley. Here both valley and stream have been modified by quarrying activities (disused nineteenth century Freestone Quarry) and the M90 which crosses the valley. The watercourse has been modified by culverting (M90), bank walling and weir construction. However, despite this the channel has many sections which are characterised by a diverse channel morphology. Evidence of localised engineering modification principally in the form of culverting and occasional bank protection. Water Quality: Not classified under SEPA’s Water Quality Classification. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from agriculture. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low
Brankholm Burn (10.59 km² catchment)	C (Poor)	Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding within Rosyth, both to the west and the east of the M90 and the proposed locations of route options North Corridor Option 1 and North Corridor Option 2, with possible extensive inundation of the surrounding land, including domestic and commercial properties, a school and an industrial estate. Fluvial Geomorphology: Brankholm Burn is a tributary of Keithing Burn. The watercourse originates in an area of agriculturally dominated land to the west of Rosyth, however, the urban area of Rosyth dominates much of the catchment. The urbanisation of the catchment has led to extensive modifications to the channel of the burn. The channel has been realigned involving extensive straightening, deepening and localised bank walling. The watercourse is culverted in several places. In general, the watercourse exhibits very limited morphological diversity and shows little evidence of active channel erosion and deposition. Water Quality: Classified under SEPA’s water quality classification system as Class C (poor). No designated water-dependent ecosystems. Considered to be of local or low environmental importance. Lake present by Belleknowes Industrial Estate in area bounded by the M90, the A921 and the railway.	Hydrology / Flood Risk: High Geomorphology: Low Water Quality: Low
Keithing Burn (19.08 km² catchment)	C (Poor) / B (Fair)	Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding at its confluence with the Pinkerton Burn and for approximately 1km upstream and downstream to its confluence with the Brankholm Burn with extensive inundation of the surrounding land. The flows from this burn contribute to the extensive inundation as discussed above. Some property and infrastructure would be directly affected by the Keithing Burn flooding. Flood risk is limited to land just outwith the banks from the location of Bois Bridge and the confluence with the Brankholm Burn downstream to the Inner Inverkeithing Bay. Fluvial Geomorphology: Keithing Burn is a large gravel-bed stream (approximately 2m wide) located within a broad valley. The watercourse is approximately 7km in length and enters the Firth of Forth at Inverkeithing Bay. Relatively large catchment area which encompasses 4 main tributaries Fordell Burn, Balbougie Burn, Pinkerton Burn and Brankholm Burn. The channel shows evidence of past modification with sections of relatively straight uniform channel morphology. Despite this however, there are sections of more diverse channel morphology where the channel appears to have readjusted following past modifications. Evidence of extensive watercourse engineering modification principally in the form of channel realignment. However the watercourse has a varied bed morphology and appears to have adjusted to this modification. Water Quality: Classified under SEPA’s water quality classification system as Class C (Poor) upstream of confluence with Brankholm Burn, improving to Class B (Fair) downstream of confluence.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium
Unnamed tributary of Brankholm Burn (5.7km² catchment)	Unclassified	Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding where it meets the Brankholm Burn within Rosyth. Upstream of the confluence, flood risk is restricted to land just outwith the banks of the tributary. The flows from this burn contribute to the extensive inundation as discussed above, both to the west and the east of the M90. Fluvial Geomorphology: Not assessed as not crossed. Water Quality: Currently not classified under the SEPA Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest good dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from urban and industrial sources. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Low Geomorphology: Not applicable Water Quality: Low
Unnamed ditch (south of Masterton Junction)	Unclassified	Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding in the area adjacent to Inverkeithing North and East junctions near the confluences of the Pinkerton, Brankholm and Keithing Burns. Fluvial Geomorphology: This gravel-bed stream issues from a pond to the southwest of Inverkeithing North Railway Junction and flows in an easterly direction through an area of grazed land before turning south, beneath a railway line and through an urban area before joining Brankholm Burn. There is a continuous riparian strip approximately 1.5m wide either side of the channel where it is located within agricultural land. The channel has been extensively modified through realignment (straightening), bank walling and culverting. The water is turbid and flow was ponded at the time of survey. The bed has a uniform morphology and is smothered by silt along much of the length of the channel. Locally there is iron staining of the bed sediments; the source of this appears to be a field drain. Water Quality: Not classified under the SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest good dissolved oxygen (DO) and pH levels. However, this is a small watercourse acting predominantly as a drainage channel considered likely to receive anthropogenic pressure from urban and industrial sources. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low
The Cast	Unclassified	Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding at the confluence with the Keithing Burn. The flows from this watercourse could contribute to the extensive inundation as discussed above. Fluvial Geomorphology: The Cast is an artificial watercourse which flows from Mill Lade at Scotts Mill to the Keithing Burn. The watercourse has a uniform trapezoidal channel morphology with a straight planform. Immediately upstream of its confluence with Keithing Burn, the watercourse is culverted to enable it to pass beneath the A921. Extensively engineered channel with very uniform morphology. The relationship of the watercourse to the surrounding topography suggests the watercourse may be artificial in origin. Water Quality: Not classified under SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest good dissolved oxygen (DO) and pH levels. However, this is a small watercourse acting predominantly as a drainage channel likely to receive anthropogenic pressure from agriculture. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low
Unnamed ditch of Keithing Burn	Unclassified	Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding at the confluence with the Keithing Burn. The flows from this burn contribute to the extensive inundation as discussed above. Fluvial Geomorphology: This unnamed ditch exhibits a straight channel with a highly uniform trapezoidal morphology. It flows into Keithing Burn at NT 13268365. It may be connected to Mill Lade upstream at an old derelict mill. Water Quality: Not classified under SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. Small watercourse acting predominantly as a drainage channel likely to receive anthropogenic pressure from agriculture. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Medium Geomorphology: Low Water Quality: Low
Southern Study Area
Swine Burn (30.64 km² catchment)	A2 (Good) / C (Poor)	Hydrology and Flood Risk: Hydrological connectivity with Humbie Reservoir. From Kirkliston upstream to Humbie Reservoir the risk of flooding is shown by SEPA as limited to land just outwith the banks; upstream of Humbie Reservoir where the burn crosses the survey boundary there is significant inundation shown to the west and east of the M9 crossing, mainly on the land on the northern bankside. Land at Humbie Reservoir is also shown to be at risk of localised flooding. Fluvial Geomorphology: Swine Burn is a tributary of the River Almond. The stream flows in a south easterly direction through a predominantly rural catchment which includes mixed and broadleaf woodland and agricultural land. The lowermost reaches pass through the urban area of Kirkliston. The watercourse is interrupted by Humbie Reservoir (online) and a lake to the west of Kirkliston. These lakes act as sinks for fine sediment. The stream has a gravel bed which frequently shows a high degree of morphological diversity in the form of pools and riffles. The channel has however been modified in a number of places through localised straightening and deepening. Here the watercourse shows little variation in form. Despite this, the watercourse is characterised by several sections with good morphological diversity and a more sinuous planform. Evidence of engineering modification principally in the form of localised channel realignment, but the channel is also characterised by sections of high morphological diversity. Water Quality: Classified under SEPA’s water quality classification system as generally of Class A2 (Good), apart from a localised stretch (80m-120m) of Class C (Poor) water quality upstream of confluence with River Almond in vicinity of distillery (approx. NGR NT1228 7430). No designated water-dependent ecosystems. Lake present southwest of Kirkliston. Hopetoun Fishery pond located within Swine Burn Wood.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium
Unnamed tributary of Swine Burn	Unclassified	Hydrology and Flood Risk: At risk of flooding at Charles Bridge and Ross’s Plantation adjacent to the M9, just upstream of its confluence with the Swine Burn. Fluvial Geomorphology: This short watercourse originates in Ross’s Plantation to the west of the M9 near Charles Bridge. This gravel-bed stream has been extensively modified by straightening and culverting. More than half the length of this watercourse is contained within a culvert beneath the M9. The bed of the watercourse is smothered by fine sediments which results in low morphological diversity and limited flow variation. Short watercourse which is extensively culverted under the M9. Water Quality: Not classified under SEPA’s Water Quality Classification Scheme and no spot sampling chemistry data available. This is a small watercourse acting predominantly as a drainage channel considered likely to receive anthropogenic pressure from agriculture and forestry. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Medium Geomorphology: Low Water Quality: Low
Humbie Reservoir	Unclassified	Hydrology and Flood Risk: Hydrological connectivity with Swine Burn, shown to be at risk of flooding on the SEPA flood map Fluvial Geomorphology: Not assessed as not crossed. Water Quality: Not classified under SEPA’s Water Quality Classification Scheme and no spot sampling chemistry data available. Impounded river forming a reservoir standing water stocked for angling. No designated water-dependent ecosystems, however considered important for local fisheries interest.	Hydrology / Flood Risk: Medium Geomorphology: Not applicable Water Quality: Medium
Niddry Burn (20.64 km² catchment)	B (Fair)	Hydrology and Flood Risk: No risk of flooding is indicated by SEPA, although this burn contributes flows to the Almond at Maitland Bridge where there is significant inundation on the opposite bank. Fluvial Geomorphology: Niddry Burn is a tributary of the River Almond located to the west of Kirkliston. This gravel-bed stream has been subject to localised modifications in the form of localised realignment and culverting; the watercourse is crossed by the M9. Despite the localised modifications, the watercourse exhibits a number of sections with good morphological diversity and evidence of active bed sediment movement. The channel bed is characterised by pools and riffles and occasional exposed gravel bars are also present. The watercourse is re-naturalising following past modification towards a more natural morphology. Water Quality: Classified under SEPA’s water quality classification system as Class B (Fair). However, it is included in the designation with the River Almond under Freshwater Fisheries Directive (2006/44/EC) as proposed salmonid waters and considered as high environmental importance.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: High
Dolphington Burn (3.7km² catchment)	B (Fair) / C (Poor)	Hydrology and Flood Risk: SEPA indicate this burn is at risk of flooding downstream of the rail crossing at Dalmeny and towards the Firth of Forth, and is generally limited to land just outwith the banks with the exception of slightly more inundation on the north side of the A90 to the east of Dalmeny. Fluvial Geomorphology: Dolphington Burn is located to the south of South Queensferry. The watercourse originates within the Dundas Estate and flows in an easterly direction to the south of Dalmeny. Downstream of the A90 trunk road, to the east of Dalmeny, the burn becomes known as Cockle Burn. This gravel-bed stream has been subject to extensive channel modifications along its entire length. It has been extensively realigned to follow tracks and field boundaries. There is also evidence that the watercourse is periodically dredged to improve flow conveyance. The watercourse flows through a mixture of mixed woodland and agricultural land and has several tributaries, primarily field drains. The burn is frequently culverted where it passes beneath roads, railways and the oil storage depot at Dalmeny. As a result of this extensive modification, the watercourse has a very uniform morphology with little evidence of active fluvial processes. However, where the watercourse passes beneath the recently completed M9 spur road, the channel shows evidence of active adjustment to recent channel engineering. The channel has been realigned under the M9 through a bridge. Here the watercourse has been straightened, deepened and re-profiled. The banks are steep and free from vegetation. As a consequence of this modification the toe of the bank (lower 0.3m) has been eroded by recent high flows releasing sediment downstream, which has created localised areas of siltation. Evidence of extensive watercourse engineering modification principally in the form of historic channel straightening and recent culverting and channel realignment associated with the M9 motorway. Water Quality: Classified under SEPA’s water quality classification system as Class B (Fair) upstream of oil storage depot, degrading to Class C (Poor) downstream. No designated water-dependent ecosystems. Considered to be of local or low environmental importance. Two ponds (offline) located by railway lines southwest of Dalmeny.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low
Linn Mill Burn (2.99 km² catchment)	Unclassified	Hydrology and Flood Risk: SEPA indicate no risk of flooding for this burn, although there is risk of flooding from the Firth of Forth at this location. Fluvial Geomorphology: Linn Mill Burn is a gravel bed stream of approximately 3.5 km in length which flows in a northerly direction through a rural catchment to the Firth of Forth. The watercourse is characterised by a low sinuosity gravel-bed channel. The watercourse has been modified in a number of places through realignment and channel deepening to improve the surrounding agricultural land. Despite this modification the watercourse has a diverse bed morphology with occasional pools and riffles leading to varied flow. In places the channel shows evidence of geomorphological adjustment to past engineering through the formation of a more sinuous channel course. The watercourse is culverted in a number of places including a relatively long stretch through fields to the south of the A904 road. Evidence of extensive watercourse engineering modification principally in the form of channel realignment. However the watercourse has a varied bed morphology and appears to have adjusted to this modification. Water Quality: Not classified under SEPA’s water quality classification system. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from agriculture and urban wastewater. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low
River Almond (388.13 km² catchment)	B (Fair) / C (Poor)	Hydrology and Flood Risk: Main watercourse in Southern study area, approx. 50km long. Flood Risk: to the southeast of Kirkliston is shown by SEPA to be at risk of flooding, with quite extensive inundation on the southern bank. The risk continues upstream where the M9 crosses the Almond and in Newbridge. Fluvial Geomorphology: Not assessed as not crossed. Water Quality: Classified under SEPA’s water quality classification system as generally Class B (Fair), with a short stretch of Class C (poor). Designated under Freshwater Fisheries Directive (2006/44/EC) as a proposed salmonid water; designated as a Site of Importance for Nature Conservation (SINC) at county / authority level and considered to be of high environmental importance.	Hydrology / Flood Risk: Medium Geomorphology: Not applicable Water Quality: High

Water Feature

SEPA Class

Baseline description

Sensitivity

Firth of Forth

B (Good)

Hydrology and Flood Risk: The coastline in the survey area is shown by SEPA to be at risk of flooding from the sea on both the North and South shores of the Firth of Forth.

Coastal Geomorphology: The Firth of Forth is an important estuarine water resource and is of international ecological importance (Firth of Forth SSSI, SPA, and Ramsar) providing habitat (intertidal flat, saltmarsh and rocky shores) for waterfowl and waders. The shoreline in the immediate vicinity of the proposed crossing is also designated as SSSI for its geomorphological and geological value.

The proposed crossing is within the Lower Firth of Forth Transitional Water Body (ID 200435) in the Scotland River Basin District as classified by SEPA (2008). Its typology is defined as partly mixed / stratified, mesohaline / polyhaline, strongly mesotidal and sheltered. The water body is identified as WFD risk status: 2a not at risk (probably). It is not considered as a whole to be heavily modified. Identified morphological alteration pressures include dredging (resulting in sediment removal) and land reclamation.

Immediately to the west of the proposed crossing on the north bank of the Firth of Forth is the St Margaret’s Marsh SSSI. This 26.4 hectares of coastal habitat supports an extensive area of coastal reedbed, saltmarsh, tall herb vegetation and scrub.

The morphology of the shoreline of the Firth of Forth is heavily modified by engineering structures including the protruding walls and associated infrastructure of the Port of Rosyth (North Shore) and Port Edgar (South Shore); land claim and sea defence structures at North Queensferry and St Margaret’s Marsh (North Shore) and South Queensferry (South Shore); engineered bridge structures relating to the Forth Road Bridge and Forth Rail Bridge affect both the North and South shorelines of the Firth of Forth, as well as the in-channel morphology.

Water Quality: The Firth of Forth including the waters surrounding the proposed bridge crossing is classified under the SEPA estuarine water quality classification system as Class B (Good). Considered to receive anthropogenic pressure from sewage, industrial and road drainage discharges. However, areas of the estuary are of high environmental importance with areas of water-dependent ecosystems designated as SPA, Ramsar sites and SSSIs.

Hydrology / Flood Risk: High

Geomorphology: High

Water Quality: High

Northern Study Area

Balbougie Burn

(1.5 km² catchment)

Unclassified

Hydrology and Flood Risk: Flooding is not currently indicated by SEPA for this tributary.

Fluvial Geomorphology: This gravel-bedded stream is a tributary of Keithing Burn, approximately 3.5 km in length. For the majority of its length the burn is set within a steep-sided wooded v-shaped valley. Within the wooded gorge the channel has a sinuous planform with varied channel morphology. However, the watercourse is extensively culverted in its middle reaches where it passes under the M90 and B981 roads. Where the watercourse is located in an area of farmland (upper and lower reaches) the channel is straighter and more uniform in character and appears to reflect past channel modification. Evidence of localised engineering modification principally in the form of culverting and occasional bank protection.

Water Quality: Not classified under SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from agriculture and road drainage. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology/ Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Pinkerton Burn

(2.58km² catchment)

Unclassified

Hydrology and Flood Risk: shown by SEPA not to be at risk of flooding upstream of the confluence with the Keithing Burn.

Fluvial Geomorphology: Pinkerton Burn is a tributary of Keithing Burn. This gravel-bed stream is approximately 2.5 km long. In its upper reaches, the catchment is dominated by recently constructed housing estates built on former farmland. Here the watercourse appears to have been subject to channel modifications in the form of localised realignment. In its middle reaches the watercourse is located in a steep-sided v-shaped gorge-like valley. Here both valley and stream have been modified by quarrying activities (disused nineteenth century Freestone Quarry) and the M90 which crosses the valley. The watercourse has been modified by culverting (M90), bank walling and weir construction. However, despite this the channel has many sections which are characterised by a diverse channel morphology. Evidence of localised engineering modification principally in the form of culverting and occasional bank protection.

Water Quality: Not classified under SEPA’s Water Quality Classification. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from agriculture. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Brankholm Burn

(10.59 km² catchment)

C (Poor)

Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding within Rosyth, both to the west and the east of the M90 and the proposed locations of route options North Corridor Option 1 and North Corridor Option 2, with possible extensive inundation of the surrounding land, including domestic and commercial properties, a school and an industrial estate.

Fluvial Geomorphology: Brankholm Burn is a tributary of Keithing Burn. The watercourse originates in an area of agriculturally dominated land to the west of Rosyth, however, the urban area of Rosyth dominates much of the catchment. The urbanisation of the catchment has led to extensive modifications to the channel of the burn. The channel has been realigned involving extensive straightening, deepening and localised bank walling. The watercourse is culverted in several places. In general, the watercourse exhibits very limited morphological diversity and shows little evidence of active channel erosion and deposition.

Water Quality: Classified under SEPA’s water quality classification system as Class C (poor). No designated water-dependent ecosystems. Considered to be of local or low environmental importance. Lake present by Belleknowes Industrial Estate in area bounded by the M90, the A921 and the railway.

Hydrology / Flood Risk: High

Geomorphology: Low

Water Quality: Low

Keithing Burn

(19.08 km² catchment)

C (Poor) / B (Fair)

Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding at its confluence with the Pinkerton Burn and for approximately 1km upstream and downstream to its confluence with the Brankholm Burn with extensive inundation of the surrounding land. The flows from this burn contribute to the extensive inundation as discussed above. Some property and infrastructure would be directly affected by the Keithing Burn flooding. Flood risk is limited to land just outwith the banks from the location of Bois Bridge and the confluence with the Brankholm Burn downstream to the Inner Inverkeithing Bay.

Fluvial Geomorphology: Keithing Burn is a large gravel-bed stream (approximately 2m wide) located within a broad valley. The watercourse is approximately 7km in length and enters the Firth of Forth at Inverkeithing Bay. Relatively large catchment area which encompasses 4 main tributaries Fordell Burn, Balbougie Burn, Pinkerton Burn and Brankholm Burn. The channel shows evidence of past modification with sections of relatively straight uniform channel morphology. Despite this however, there are sections of more diverse channel morphology where the channel appears to have readjusted following past modifications. Evidence of extensive watercourse engineering modification principally in the form of channel realignment. However the watercourse has a varied bed morphology and appears to have adjusted to this modification.

Water Quality: Classified under SEPA’s water quality classification system as Class C (Poor) upstream of confluence with Brankholm Burn, improving to Class B (Fair) downstream of confluence.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Unnamed tributary of Brankholm Burn

(5.7km² catchment)

Unclassified

Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding where it meets the Brankholm Burn within Rosyth. Upstream of the confluence, flood risk is restricted to land just outwith the banks of the tributary. The flows from this burn contribute to the extensive inundation as discussed above, both to the west and the east of the M90.

Fluvial Geomorphology: Not assessed as not crossed.

Water Quality: Currently not classified under the SEPA Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest good dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from urban and industrial sources. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood Risk: Low

Geomorphology: Not applicable

Water Quality: Low

Unnamed ditch (south of Masterton Junction)

Unclassified

Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding in the area adjacent to Inverkeithing North and East junctions near the confluences of the Pinkerton, Brankholm and Keithing Burns.

Fluvial Geomorphology: This gravel-bed stream issues from a pond to the southwest of Inverkeithing North Railway Junction and flows in an easterly direction through an area of grazed land before turning south, beneath a railway line and through an urban area before joining Brankholm Burn. There is a continuous riparian strip approximately 1.5m wide either side of the channel where it is located within agricultural land. The channel has been extensively modified through realignment (straightening), bank walling and culverting. The water is turbid and flow was ponded at the time of survey. The bed has a uniform morphology and is smothered by silt along much of the length of the channel. Locally there is iron staining of the bed sediments; the source of this appears to be a field drain.

Water Quality: Not classified under the SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest good dissolved oxygen (DO) and pH levels. However, this is a small watercourse acting predominantly as a drainage channel considered likely to receive anthropogenic pressure from urban and industrial sources. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

The Cast

Unclassified

Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding at the confluence with the Keithing Burn. The flows from this watercourse could contribute to the extensive inundation as discussed above.

Fluvial Geomorphology: The Cast is an artificial watercourse which flows from Mill Lade at Scotts Mill to the Keithing Burn. The watercourse has a uniform trapezoidal channel morphology with a straight planform. Immediately upstream of its confluence with Keithing Burn, the watercourse is culverted to enable it to pass beneath the A921. Extensively engineered channel with very uniform morphology. The relationship of the watercourse to the surrounding topography suggests the watercourse may be artificial in origin.

Water Quality: Not classified under SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest good dissolved oxygen (DO) and pH levels. However, this is a small watercourse acting predominantly as a drainage channel likely to receive anthropogenic pressure from agriculture. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Unnamed ditch of Keithing Burn

Unclassified

Hydrology and Flood Risk: Shown by SEPA to be at risk of flooding at the confluence with the Keithing Burn. The flows from this burn contribute to the extensive inundation as discussed above.

Fluvial Geomorphology: This unnamed ditch exhibits a straight channel with a highly uniform trapezoidal morphology. It flows into Keithing Burn at NT 13268365. It may be connected to Mill Lade upstream at an old derelict mill.

Water Quality: Not classified under SEPA’s Water Quality Classification Scheme. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. Small watercourse acting predominantly as a drainage channel likely to receive anthropogenic pressure from agriculture. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood Risk: Medium

Geomorphology: Low

Water Quality: Low

Southern Study Area

Swine Burn

(30.64 km² catchment)

A2 (Good) / C (Poor)

Hydrology and Flood Risk: Hydrological connectivity with Humbie Reservoir. From Kirkliston upstream to Humbie Reservoir the risk of flooding is shown by SEPA as limited to land just outwith the banks; upstream of Humbie Reservoir where the burn crosses the survey boundary there is significant inundation shown to the west and east of the M9 crossing, mainly on the land on the northern bankside. Land at Humbie Reservoir is also shown to be at risk of localised flooding.

Fluvial Geomorphology: Swine Burn is a tributary of the River Almond. The stream flows in a south easterly direction through a predominantly rural catchment which includes mixed and broadleaf woodland and agricultural land. The lowermost reaches pass through the urban area of Kirkliston. The watercourse is interrupted by Humbie Reservoir (online) and a lake to the west of Kirkliston. These lakes act as sinks for fine sediment. The stream has a gravel bed which frequently shows a high degree of morphological diversity in the form of pools and riffles. The channel has however been modified in a number of places through localised straightening and deepening. Here the watercourse shows little variation in form. Despite this, the watercourse is characterised by several sections with good morphological diversity and a more sinuous planform. Evidence of engineering modification principally in the form of localised channel realignment, but the channel is also characterised by sections of high morphological diversity.

Water Quality: Classified under SEPA’s water quality classification system as generally of Class A2 (Good), apart from a localised stretch (80m-120m) of Class C (Poor) water quality upstream of confluence with River Almond in vicinity of distillery (approx. NGR NT1228 7430). No designated water-dependent ecosystems. Lake present southwest of Kirkliston. Hopetoun Fishery pond located within Swine Burn Wood.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Unnamed tributary of Swine Burn

Unclassified

Hydrology and Flood Risk: At risk of flooding at Charles Bridge and Ross’s Plantation adjacent to the M9, just upstream of its confluence with the Swine Burn.

Fluvial Geomorphology: This short watercourse originates in Ross’s Plantation to the west of the M9 near Charles Bridge. This gravel-bed stream has been extensively modified by straightening and culverting. More than half the length of this watercourse is contained within a culvert beneath the M9. The bed of the watercourse is smothered by fine sediments which results in low morphological diversity and limited flow variation. Short watercourse which is extensively culverted under the M9.

Water Quality: Not classified under SEPA’s Water Quality Classification Scheme and no spot sampling chemistry data available. This is a small watercourse acting predominantly as a drainage channel considered likely to receive anthropogenic pressure from agriculture and forestry. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood Risk: Medium

Geomorphology: Low

Water Quality: Low

Humbie Reservoir

Unclassified

Hydrology and Flood Risk: Hydrological connectivity with Swine Burn, shown to be at risk of flooding on the SEPA flood map

Fluvial Geomorphology: Not assessed as not crossed.

Water Quality: Not classified under SEPA’s Water Quality Classification Scheme and no spot sampling chemistry data available. Impounded river forming a reservoir standing water stocked for angling. No designated water-dependent ecosystems, however considered important for local fisheries interest.

Hydrology / Flood Risk: Medium

Geomorphology: Not applicable

Water Quality: Medium

Niddry Burn

(20.64 km² catchment)

B (Fair)

Hydrology and Flood Risk: No risk of flooding is indicated by SEPA, although this burn contributes flows to the Almond at Maitland Bridge where there is significant inundation on the opposite bank.

Fluvial Geomorphology: Niddry Burn is a tributary of the River Almond located to the west of Kirkliston. This gravel-bed stream has been subject to localised modifications in the form of localised realignment and culverting; the watercourse is crossed by the M9. Despite the localised modifications, the watercourse exhibits a number of sections with good morphological diversity and evidence of active bed sediment movement. The channel bed is characterised by pools and riffles and occasional exposed gravel bars are also present. The watercourse is re-naturalising following past modification towards a more natural morphology.

Water Quality: Classified under SEPA’s water quality classification system as Class B (Fair). However, it is included in the designation with the River Almond under Freshwater Fisheries Directive (2006/44/EC) as proposed salmonid waters and considered as high environmental importance.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: High

Dolphington Burn

(3.7km² catchment)

B (Fair) / C (Poor)

Hydrology and Flood Risk: SEPA indicate this burn is at risk of flooding downstream of the rail crossing at Dalmeny and towards the Firth of Forth, and is generally limited to land just outwith the banks with the exception of slightly more inundation on the north side of the A90 to the east of Dalmeny.

Fluvial Geomorphology: Dolphington Burn is located to the south of South Queensferry. The watercourse originates within the Dundas Estate and flows in an easterly direction to the south of Dalmeny. Downstream of the A90 trunk road, to the east of Dalmeny, the burn becomes known as Cockle Burn. This gravel-bed stream has been subject to extensive channel modifications along its entire length. It has been extensively realigned to follow tracks and field boundaries. There is also evidence that the watercourse is periodically dredged to improve flow conveyance. The watercourse flows through a mixture of mixed woodland and agricultural land and has several tributaries, primarily field drains. The burn is frequently culverted where it passes beneath roads, railways and the oil storage depot at Dalmeny. As a result of this extensive modification, the watercourse has a very uniform morphology with little evidence of active fluvial processes. However, where the watercourse passes beneath the recently completed M9 spur road, the channel shows evidence of active adjustment to recent channel engineering. The channel has been realigned under the M9 through a bridge. Here the watercourse has been straightened, deepened and re-profiled. The banks are steep and free from vegetation. As a consequence of this modification the toe of the bank (lower 0.3m) has been eroded by recent high flows releasing sediment downstream, which has created localised areas of siltation. Evidence of extensive watercourse engineering modification principally in the form of historic channel straightening and recent culverting and channel realignment associated with the M9 motorway.

Water Quality: Classified under SEPA’s water quality classification system as Class B (Fair) upstream of oil storage depot, degrading to Class C (Poor) downstream. No designated water-dependent ecosystems. Considered to be of local or low environmental importance. Two ponds (offline) located by railway lines southwest of Dalmeny.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Linn Mill Burn

(2.99 km² catchment)

Unclassified

Hydrology and Flood Risk: SEPA indicate no risk of flooding for this burn, although there is risk of flooding from the Firth of Forth at this location.

Fluvial Geomorphology: Linn Mill Burn is a gravel bed stream of approximately 3.5 km in length which flows in a northerly direction through a rural catchment to the Firth of Forth. The watercourse is characterised by a low sinuosity gravel-bed channel. The watercourse has been modified in a number of places through realignment and channel deepening to improve the surrounding agricultural land. Despite this modification the watercourse has a diverse bed morphology with occasional pools and riffles leading to varied flow. In places the channel shows evidence of geomorphological adjustment to past engineering through the formation of a more sinuous channel course. The watercourse is culverted in a number of places including a relatively long stretch through fields to the south of the A904 road. Evidence of extensive watercourse engineering modification principally in the form of channel realignment. However the watercourse has a varied bed morphology and appears to have adjusted to this modification.

Water Quality: Not classified under SEPA’s water quality classification system. Spot sampling (Jacobs Arup, 2008) results suggest excellent dissolved oxygen (DO) and pH levels. However, this is a small watercourse considered likely to receive anthropogenic pressure from agriculture and urban wastewater. No designated water-dependent ecosystems. Considered to be of local or low environmental importance.

Hydrology / Flood

Risk: Low

Geomorphology: Medium

Water Quality: Low

River Almond

(388.13 km² catchment)

B (Fair) / C (Poor)

Hydrology and Flood Risk: Main watercourse in Southern study area, approx. 50km long. Flood Risk: to the southeast of Kirkliston is shown by SEPA to be at risk of flooding, with quite extensive inundation on the southern bank. The risk continues upstream where the M9 crosses the Almond and in Newbridge.

Fluvial Geomorphology: Not assessed as not crossed.

Water Quality: Classified under SEPA’s water quality classification system as generally Class B (Fair), with a short stretch of Class C (poor). Designated under Freshwater Fisheries Directive (2006/44/EC) as a proposed salmonid water; designated as a Site of Importance for Nature Conservation (SINC) at county / authority level and considered to be of high environmental importance.

Hydrology / Flood Risk: Medium

Geomorphology: Not applicable

Water Quality: High

8.4 Potential Impacts

8.4.1 This section describes the potential impacts on the water environment that could arise in the absence of mitigation, during construction and operation of the proposed scheme.

8.4.2 Impacts on the water environment are described separately for construction and operation for each of the three specialist disciplines as detailed in Section 8.2 (Approach and Methods).

8.4.3 Generic potential impacts for each discipline are described, followed by specific impacts on water features for each of the route corridor options, during the construction and operational phases of the scheme.

8.4.4 It is emphasised that the potential impacts presented in this section are assessed assuming no mitigation and hence represent the worst-case scenario for the water environment. These impacts are identified with the principal purpose of comparing route corridor options.

Potential Impacts During Construction

8.4.5 Construction impacts on the water environment are often of short-term duration, although in some cases these can have longer term indirect impacts on dependent freshwater habitats. Impacts are likely to be more intense than during the long-term operational phase, due to the heightened concentration of activities occurring in, or near the waters during this period.

Hydrology and Flood Risk

8.4.6 Potential construction impacts include effects such as increased runoff from soil compaction due to works traffic, sedimentation and disturbance / unintentional changes to channel dimensions which may impact on the hydraulic flow characteristics of a watercourse as well as on geomorphology, ecology and water quality.

8.4.7 During the construction phase, other temporary works that potentially may affect surface hydrology include the following:

temporary watercourse diversions to facilitate culvert or bridge construction and any associated temporary works;
watercourse diversions and re-direction through constructed realignments or into pre-earthwork ditches;
temporary attenuation features at drainage outfalls; and
temporary arrangements to control runoff.

Fluvial and Coastal Geomorphology

8.4.8 Potential impacts on fluvial geomorphology during construction include:

alterations to channel morphology during the construction of crossing structures, such as bridges or culverts, and associated channel modifications and the release of sediment into the watercourse; and
sediment release during in-channel works, site clearance operations and earthworks in the vicinity of watercourses.

8.4.9 These impacts would be likely to be concentrated in locations where construction activities occur within or in the immediate vicinity of watercourses. At this stage, because the likely nature of the construction activities is not known, the relative magnitude of impact is assessed on the broad nature and extent of the channel engineering required (Table 8.2).

8.4.10 Potential impacts on the coastal / estuarine geomorphology of the Firth of Forth during construction could involve alterations to the shoreline and channel morphology during the construction of the crossing structure (i.e. bridge) and the potential for associated release of sediment into the watercourse.

Water Quality

8.4.11 Construction activities may impact on water quality through accidental spillages or disturbance of potentially contaminated land. The potential areas of contaminated land are considered within Chapter 7 (Geology, Contaminated Land and Groundwater). Impacts on water quality are likely to be short-term but may have a longer term indirect effect on aquatic ecology (Chapter 9: Ecology and Nature Conservation).

8.4.12 Potential impacts to water quality during the construction phase include:

release of turbid site runoff water into watercourse;
spillage of oils, fuels and chemicals from mobile or stationary plant, resulting in adverse impacts to water quality and freshwater ecology;
accidental release of concrete, cement and admixtures into watercourses, increasing the alkalinity of the waters and therefore affecting freshwater ecology;
erosion and sedimentation can result from construction works and adversely affect water quality and ecology;
accidental / uncontrolled release of sewage from sewers through damage to pipelines during service diversion or unsatisfactory disposal of sewage from site staff facilities; and
disturbance of potentially contaminated land with potential drainage pathways to surface waters.

Proposed Replacement Bridge (Construction)

8.4.13 The main impacts to the Firth of Forth during the construction phase would result from the bridge construction and associated infrastructure (Table 8.5).

Table 8.5: Summary of Potential Impacts During Construction – Firth of Forth

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Firth of Forth	Hydrology / Flood Risk: High Geomorphology: High Water Quality: High	Hydrology and Flood Risk: Increased runoff from construction site. Coastal Geomorphology: Alterations to the shoreline and channel morphology during construction of the bridge and potential for associated release of sediment into the watercourse. Sediment release is likely to arise from shoreline and in-channel works, site clearance operations and earthworks in the vicinity of the estuary. The magnitude of impact of these activities would depend upon the extent of the shoreline and in-channel engineering required. Water Quality: Potential risk of accidental spillage of pollutants during construction due to proximity of works to estuary. Bridging is likely to involve extensive earthworks, which may result in sediment release leading to short to medium term increase to suspended sediment loads and turbidity within the channel. However the estuary provides a high dilution capacity.	Hydrology / Flood Risk: Negligible Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Negligible Geomorphology: Moderate / Substantial Water Quality: Moderate / Substantial

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Firth of Forth

Hydrology / Flood Risk: High

Geomorphology: High

Water Quality: High

Hydrology and Flood Risk: Increased runoff from construction site.

Coastal Geomorphology: Alterations to the shoreline and channel morphology during construction of the bridge and potential for associated release of sediment into the watercourse. Sediment release is likely to arise from shoreline and in-channel works, site clearance operations and earthworks in the vicinity of the estuary. The magnitude of impact of these activities would depend upon the extent of the shoreline and in-channel engineering required.

Water Quality: Potential risk of accidental spillage of pollutants during construction due to proximity of works to estuary. Bridging is likely to involve extensive earthworks, which may result in sediment release leading to short to medium term increase to suspended sediment loads and turbidity within the channel. However the estuary provides a high dilution capacity.

Hydrology / Flood Risk: Negligible

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate / Substantial

Water Quality: Moderate / Substantial

Northern Route Corridor Options (Construction)

8.4.14 For both route corridor options (and their respective junction arrangements) in the Northern study area, the following watercourses would be crossed, as detailed in Table 8.6.

Table 8.6: Watercourses to be Crossed by the Proposed Northern Route Corridor Options

Route Corridor Option	Watercourse crossings
North Corridor Option 1	6 crossings: Pinkerton Burn (2 crossings), Brankholm Burn, Keithing Burn, Unnamed ditch of Keithing Burn, The Cast.
North Corridor Option 2	3 crossings: Pinkerton Burn, Unnamed ditch (south of Masterton Junction), Brankholm Burn.

Impacts Common to Both Northern Route Corridor Options

8.4.15 Current route corridor options indicate that Balbougie Burn would not be crossed by either of the northern route corridor options but the proposed works to upgrade the M90 would be within approximately 150m of this watercourse (at the northern end of the routes). The significance of potential impacts on this watercourse as a result of construction are assessed as follows:

Hydrology and Flood Risk: Negligible.
Fluvial Geomorphology: Negligible.
Water Quality: Negligible.

8.4.16 Both route corridor options would pass near a lake located by Belleknowes Industrial Estate within the area bounded by the M90, the A921 and the railway. During construction, there would be a risk of pollution from site runoff to this lake.

North Corridor Option 1

8.4.17 See Table 8.7 below for a description of North Corridor Option 1 and resulting potential impacts to affected watercourses.

North Corridor Option 2

8.4.18 See Table 8.8 below for a description of North Corridor Option 2 and resulting potential impacts to affected watercourses.

Table 8.7: Summary of Potential Impacts During Construction – North Corridor Option 1

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Pinkerton Burn	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Modification to existing crossing structure. Construction of one additional crossing. Water Quality: Earthworks associated with activities (crossing replacement, crossing structure and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Negligible Geomorphology: Moderate Water Quality: Slight
Brankholm Burn	Hydrology / Flood Risk: High Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Modification to existing crossing structure. Water Quality: Earthworks associated with activities (crossing replacement and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: Moderate Geomorphology: Negligible Water Quality: Negligible
Keithing Burn	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. There will be work in the flood plain. Geomorphology: Construction of new crossing for link road. Water Quality: Earthworks associated with activities (potential outfall construction and crossing structure), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Moderate Geomorphology: Moderate Water Quality: Moderate
Unnamed Ditch of Keithing Burn	Hydrology / Flood Risk: Medium Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. There will be work in the flood plain Geomorphology: Construction of new crossing for link road. Water Quality: Earthworks associated with activities (crossing structure), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Slight Geomorphology: Slight Water Quality: Slight
The Cast	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Geomorphology: Construction of new crossing for roundabout and link road. Water Quality: Earthworks associated with activities (crossing structure), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Slight

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Pinkerton Burn

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Modification to existing crossing structure. Construction of one additional crossing.

Water Quality: Earthworks associated with activities (crossing replacement, crossing structure and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate

Water Quality: Slight

Brankholm Burn

Hydrology / Flood Risk: High

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Modification to existing crossing structure.

Water Quality: Earthworks associated with activities (crossing replacement and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: Moderate

Geomorphology: Negligible

Water Quality: Negligible

Keithing Burn

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. There will be work in the flood plain.

Geomorphology: Construction of new crossing for link road.

Water Quality: Earthworks associated with activities (potential outfall construction and crossing structure), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Moderate

Geomorphology: Moderate

Water Quality: Moderate

Unnamed Ditch of Keithing Burn

Hydrology / Flood Risk: Medium

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. There will be work in the flood plain

Geomorphology: Construction of new crossing for link road.

Water Quality: Earthworks associated with activities (crossing structure), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Slight

Geomorphology: Slight

Water Quality: Slight

The Cast

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Geomorphology: Construction of new crossing for roundabout and link road.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Slight

Table 8.8: Summary of Potential Impacts During Construction – North Corridor Option 2

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Pinkerton Burn	Hydrology/ Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of one additional crossing. Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Negligible Geomorphology: Moderate Water Quality: Slight
Brankholm Burn	Hydrology / Flood Risk: High Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of one additional crossing. Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of watercourse.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Moderate / Substantial Geomorphology: Slight Water Quality: Slight
Unnamed ditch (south of Masterton Junction)	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of one additional crossing. Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Slight
Keithing Burn	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: No direct impact as not crossed. Water Quality: Earthworks associated with activities (potential outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.	Hydrology / Flood Risk: Negligible Geomorphology: Negligible Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Negligible Water Quality: Slight

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Pinkerton Burn

Hydrology/ Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of one additional crossing.

Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate

Water Quality: Slight

Brankholm Burn

Hydrology / Flood Risk: High

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of one additional crossing.

Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of watercourse.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Moderate / Substantial

Geomorphology: Slight

Water Quality: Slight

Unnamed ditch (south of Masterton Junction)

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of one additional crossing.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Slight

Keithing Burn

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: No direct impact as not crossed.

Water Quality: Earthworks associated with activities (potential outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.

Hydrology / Flood Risk: Negligible

Geomorphology: Negligible

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Negligible

Water Quality: Slight

Southern Route Corridor Options (Construction)

8.4.19 For each of the two route corridor options south of the Firth of Forth, the watercourses that would be crossed are detailed in Table 8.9 below.

Table 8.9: Watercourses to be Crossed by the Proposed Southern Route Corridor Options

Route Corridor Option	Watercourse Crossings
South Corridor Option 1	5 crossings in total: 3 crossings of Swine Burn, 1 crossing of Niddry Burn, 1 crossing of Dolphington Burn.
South Corridor Option 2	11 crossings in total: 5 crossings of Swine Burn, 2 crossings of an unnamed tributary of Swine Burn, 1 crossing of Niddry Burn, 3 crossings of Dolphington Burn.

8.4.20 The main impacts during construction would be for the works required for watercourse crossings, realignments, temporary diversions and outfalls. The potential impacts resulting from these activities are discussed in the Impacts during Construction section above.

Impacts Common to Both Southern Route Corridor Options

8.4.21 Surface water runoff is proposed to outfall into Linn Mill Burn from either route corridor option (NGR NT 1137 7864). Significance of potential impacts to this watercourse as a result of outfall construction are as follows:

Hydrology and Flood Risk: There is the potential for faster and increased runoff to the burn than the existing situation, with Negligible significance for flood risk.
Fluvial Geomorphology: Potential release of suspended sediment due to proximity of works to watercourse with a Negligible significance impact on the geomorphology of the watercourse.
Water Quality: Potential release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse. Linn Mill Burn has been evaluated as of low sensitivity and impacts on water quality have been assessed as low magnitude and therefore Negligible significance.

South Corridor Option 1

8.4.22 See Table 8.10 below for a description of South Corridor Option 1 and resulting potential impacts to affected watercourses.

South Corridor Option 2

8.4.23 See Table 8.11 below for a description of South Corridor Option 2 and resulting potential impacts to affected watercourses.

Table 8.10: Summary of Potential Impacts During Construction – South Corridor Option 1

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Swine Burn	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of two additional crossings and modification of one existing crossing. Water Quality: Earthworks associated with activities (crossing structures and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse. Risk of pollution to lake southwest of Kirkliston.	Hydrology / Flood Risk: Low Geomorphology: High Water Quality: High	Hydrology / Flood Risk: Slight Geomorphology: Moderate / Substantial Water Quality: Moderate / Substantial
Dolphington Burn	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of one additional crossing. Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Medium	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Slight
Niddry Burn	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: High	Hydrology and Flood Risk: Crossing at junction with M9; increased runoff from construction site. Fluvial Geomorphology: Modification to existing crossing. Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Moderate

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Swine Burn

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of two additional crossings and modification of one existing crossing.

Water Quality: Earthworks associated with activities (crossing structures and perhaps realignment), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse. Risk of pollution to lake southwest of Kirkliston.

Hydrology / Flood Risk: Low

Geomorphology: High

Water Quality: High

Hydrology / Flood Risk: Slight

Geomorphology: Moderate / Substantial

Water Quality: Moderate / Substantial

Dolphington Burn

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of one additional crossing.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Medium

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Slight

Niddry Burn

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: High

Hydrology and Flood Risk: Crossing at junction with M9; increased runoff from construction site.

Fluvial Geomorphology: Modification to existing crossing.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Moderate

Table 8.11: Summary of Potential Impacts During Construction – South Corridor Option 2

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Swine Burn	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of three additional crossings and modifications to two existing crossings. Water Quality: Earthworks associated with activities (crossing structures and perhaps realignment and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse. Risk of pollution to Humbie Reservoir and to lake south of Kirkliston. In addition, potential for site runoff to enter Hopetoun Fishery pond.	Hydrology / Flood Risk: Medium at M9 Geomorphology: High Water Quality: High	Hydrology / Flood Risk: Moderate Geomorphology: Moderate / Substantial Water Quality: Moderate / Substantial
Unnamed tributary of Swine Burn	Hydrology / Flood Risk: Medium Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of one new crossing and modifications to existing crossing. Water Quality: Earthworks associated with activities (crossing structure and perhaps realignment and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: High	Hydrology / Flood Risk: Slight Geomorphology: Slight Water Quality: Moderate
Niddry Burn	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: High	Hydrology and Flood Risk: Increased runoff from construction site. Fluvial Geomorphology: Potential modification to one existing structure. Water Quality: Earthworks associated with activities (crossing structure and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Moderate
Dolphington Burn	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows. Fluvial Geomorphology: Construction of two additional crossings and modification of one existing crossing. Water Quality: Earthworks associated with activities (crossing structures and perhaps realignments), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse. Direct impact on one or both ponds southwest of Dalmeny and risk of pollution from site runoff or accidental spillage.	Hydrology / Flood Risk: Low Geomorphology: High Water Quality: High	Hydrology / Flood Risk: Negligible Geomorphology: Moderate Water Quality: Moderate

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Swine Burn

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of three additional crossings and modifications to two existing crossings.

Water Quality: Earthworks associated with activities (crossing structures and perhaps realignment and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse. Risk of pollution to Humbie Reservoir and to lake south of Kirkliston. In addition, potential for site runoff to enter Hopetoun Fishery pond.

Hydrology / Flood Risk: Medium at M9

Geomorphology: High

Water Quality: High

Hydrology / Flood Risk: Moderate

Geomorphology: Moderate / Substantial

Water Quality: Moderate / Substantial

Unnamed tributary of Swine Burn

Hydrology / Flood Risk: Medium

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of one new crossing and modifications to existing crossing.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: High

Hydrology / Flood Risk: Slight

Geomorphology: Slight

Water Quality: Moderate

Niddry Burn

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: High

Hydrology and Flood Risk: Increased runoff from construction site.

Fluvial Geomorphology: Potential modification to one existing structure.

Water Quality: Earthworks associated with activities (crossing structure and outfall construction), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low / medium dilution capacity of the watercourse.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Moderate

Dolphington Burn

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There may be requirements for temporary diversion, drainage or redirection of existing flows.

Fluvial Geomorphology: Construction of two additional crossings and modification of one existing crossing.

Water Quality: Earthworks associated with activities (crossing structures and perhaps realignments), potentially resulting in release of suspended solids and accidental pollutant spillage due to proximity of works to watercourse. Low dilution capacity of the watercourse. Direct impact on one or both ponds southwest of Dalmeny and risk of pollution from site runoff or accidental spillage.

Hydrology / Flood Risk: Low

Geomorphology: High

Water Quality: High

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate

Water Quality: Moderate

Potential Impacts During Operation

8.4.24 Adverse impacts on the water environment during the operational phase of the proposed scheme may result from various features including road drainage, watercourse crossings and watercourse realignments. The potential impacts of each of these features are described below for each discipline.

Hydrology and Flood Risk

8.4.25 Road Drainage: The route corridor options would introduce new impermeable areas to the watercourse catchment, potentially increasing the volume and peak flow of surface runoff reaching a watercourse as less would be lost to infiltration into the ground.

8.4.26 The road and its drainage system may act as a barrier to water movement within current catchments. In addition, a road scheme can potentially result in rain falling in one catchment being discharged to another via the road drainage system.

8.4.27 Watercourse crossings: Impacts of watercourse crossing on surface hydrology could occur through alteration of the physical flow and water level regimes.

8.4.28 Watercourse realignments: Realignments would potentially change the discharge regime of watercourses, however, with appropriate design in terms of hydraulic considerations, these realignments would not affect surface water hydrology unless the realignment significantly changes the catchment of the watercourse.

8.4.29 Where a route corridor option crosses a floodplain on embankment, there would be a potential loss of flood storage volume.

Fluvial and Coastal Geomorphology

8.4.30 Road Drainage: Increased discharge along the watercourse as discussed above (Hydrology and Flood Risk) may increase geomorphological activity within the channel. This could result in an increase in turbidity; greater sediment transport downstream; and increased erosion of the channel bed and banks with morphological diversity being reduced or improved depending on sediment supply.

8.4.31 The polluting load in road runoff may include fine sediment accumulations, which are washed from the road into the drainage system and discharged to receiving watercourses. Increasing the suspended sediment fraction of runoff may lead to:

channel sedimentation, causing a reduction in dynamic processes;
increased transportation (turbidity) and deposition of fine sediment (sedimentation); and
a reduction of morphological and consequently, ecological diversity due to fine sediment deposition.

8.4.32 The volume of sediment generated by the operation of the road and discharged to a particular watercourse would vary depending on the area of road from which runoff would be directed.

8.4.33 At drainage outfalls scour may occur leading to increased sediment supply / deposition, localised alterations to flow and changes to channel morphology.

8.4.34 Watercourse crossings can alter patterns of sediment transfer and deposition, and lead to loss of morphological features due to the land claim required for the footprint (e.g. bridge piers and embankments).

8.4.35 Where culverting increases the channel gradient, the scour of the bed and banks at culvert outlets often occurs, leading to an increase in the supply of sediment to the watercourse downstream.

8.4.36 Morphological diversity of a watercourse within a culvert would be greatly reduced. Culverts constrain the channel preventing lateral and vertical adjustment. The use of bridges generally reduces geomorphological impacts by maintaining morphological diversity and not constraining the bed in the same way as a culvert.

8.4.37 Watercourse Realignments: Over time realignments may lead to a change in the geomorphological behaviour of a watercourse. This includes changes to sediment supply, rate of sediment transfer downstream, and deposition zones. Disruption to the channel bed may be temporary and realignment may lead to an improvement in channel morphology. In poor quality streams, realignment provides opportunity to restore / rehabilitate low quality watercourses.

Water Quality

8.4.38 Road Drainage: During operation, the main potential impacts on water quality would be from pollutants transported in road runoff. Impacts to water quality are intrinsically linked to aquatic ecology and therefore these impacts should be read in conjunction with Chapter 9 (Ecology and Nature Conservation). These pollutants result from a number of direct and diffuse sources including vehicles (e.g. tyre rubber, brake and clutch linings, fuel, oil and coolant), highway maintenance and general road surface degradation.

8.4.39 There are a wide range of pollutants which may impact on the receiving water and its associated aquatic ecology, including:

metals such as dissolved copper, total zinc, lead and other soluble pollutants;
suspended solids and contaminants bound to them;
organic compounds such as oils and other hydrocarbons;
biodegradable organic material such as grass cuttings which can contain high levels of nutrients; and
de-icing salt and alternative de-icing agents.

8.4.40 A quantitative assessment of the potential impact of proposed highway discharges on concentrations of total zinc and dissolved copper in receiving watercourses will be undertaken at Stage 3.

8.4.41 Watercourse Crossings: As noted above, culverting could potentially change the riverbed morphological diversity and sediment regime of the watercourses which may also have associated impacts on water quality by releasing previously locked contaminants into the water.

8.4.42 Watercourse Realignments: The main impact of realignments on water quality could occur as a result of altered geomorphology. Changes to the sediment regime may re-entrain contaminated sediments and increase pollutant concentrations in the water column.

Proposed Replacement Bridge (Operation)

8.4.43 The main potential impacts to the Firth of Forth during the long-term operation phase could result from pollution incidents and accidental spillages from increased traffic loadings and vehicular collisions (see Table 8.12 below).

Table 8.12: Summary of Potential Impacts During Operation – Firth of Forth

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Firth of Forth	Hydrology / Flood Risk: High Geomorphology: High Water Quality: High	Hydrology and Flood Risk: Potential minor change to discharge regime due to road runoff to the Estuary. Coastal Geomorphology: New crossing structure (Bridge) interacting with estuarine morphology. Loss of estuarine features due to land claim for structure. Water Quality: Road runoff discharge may lead to siltation and indirect impacts on coastal habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. However the estuary provides a high dilution capacity.	Hydrology / Flood Risk: Negligible Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Moderate / Substantial Water Quality: Moderate

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Firth of Forth

Hydrology / Flood Risk: High

Geomorphology: High

Water Quality: High

Hydrology and Flood Risk: Potential minor change to discharge regime due to road runoff to the Estuary.

Coastal Geomorphology: New crossing structure (Bridge) interacting with estuarine morphology. Loss of estuarine features due to land claim for structure.

Water Quality: Road runoff discharge may lead to siltation and indirect impacts on coastal habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. However the estuary provides a high dilution capacity.

Hydrology / Flood Risk: Negligible

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate / Substantial

Water Quality: Moderate

Northern Route Corridor Options (Operation)

Impacts Common to Both Northern Route Corridor Options

8.4.44 Balbougie Burn: each route corridor option extends northwards along the M90 to the B916, approximately 150m south of the M90 crossing over Balbougie Burn. Significance of potential impacts to this watercourse during the operational phase are as follows:

Hydrology and Flood Risk: Negligible unless the route corridor options are extended further north.
Fluvial Geomorphology: Negligible unless the existing crossing structure is modified or replaced.
Water Quality: Impacts from diffuse pollution sources likely to be insignificant. No road drainage discharges are proposed to Balbougie Burn. Consequently, impacts on water quality have been assessed as of Negligible significance.

North Corridor Option 1

8.4.45 See Table 8.13 below for an assessment of potential impacts to affected watercourses during the operational phase of North Corridor Option 1.

North Corridor Option 2

8.4.46 See Table 8.14 below for an assessment of potential impacts to affected watercourses during the operational phase of North Corridor Option 2.

Table 8.13: Summary of Potential Impacts During Operation – North Corridor Option 1

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Pinkerton Burn	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology and Flood Risk: There would be greater runoff volumes than existing. Fluvial Geomorphology: Modified crossing structure and one additional crossing structure. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Moderate Water Quality: Negligible
Brankholm Burn	Hydrology / Flood Risk: High Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: Surface water runoff from the road proposed to discharge into Brankholm Burn. Change to discharge regime due to road runoff discharge to the burn may lead to siltation and the periodic requirement for dredging. There would be greater runoff volumes than existing. Fluvial Geomorphology: Modified crossing structure. Water Quality: Proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low dilution capacity of watercourse. Due to online construction there is potential to improve water quality by upgrading existing drainage of the carriageway.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: High	Hydrology / Flood Risk: Moderate Geomorphology: Negligible Water Quality: Moderate
Keithing Burn	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: Runoff may be increased and faster than baseline conditions. Flood plain will be reduced by proposed slip roads. Fluvial Geomorphology: Crossed by new link road. Water Quality: Proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low / medium dilution capacity of watercourse.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: High	Hydrology / Flood Risk: Moderate Geomorphology: Moderate Water Quality: Moderate / Substantial
Unnamed ditch of Keithing Burn	Hydrology / Flood Risk: Medium Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: Runoff may be increased and faster than baseline conditions. Flood plain will be reduced by proposed slip roads. Geomorphology: Crossed by new link road. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Slight Geomorphology: Slight Water Quality: Negligible
The Cast	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: Runoff may be increased and faster than baseline conditions. Geomorphology: New crossing for roundabout and link road. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Negligible

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Pinkerton Burn

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology and Flood Risk: There would be greater runoff volumes than existing.

Fluvial Geomorphology: Modified crossing structure and one additional crossing structure.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate

Water Quality: Negligible

Brankholm Burn

Hydrology / Flood Risk: High

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: Surface water runoff from the road proposed to discharge into Brankholm Burn. Change to discharge regime due to road runoff discharge to the burn may lead to siltation and the periodic requirement for dredging. There would be greater runoff volumes than existing.

Fluvial Geomorphology: Modified crossing structure.

Water Quality: Proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low dilution capacity of watercourse. Due to online construction there is potential to improve water quality by upgrading existing drainage of the carriageway.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: High

Hydrology / Flood Risk: Moderate

Geomorphology: Negligible

Water Quality: Moderate

Keithing Burn

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: Runoff may be increased and faster than baseline conditions. Flood plain will be reduced by proposed slip roads.

Fluvial Geomorphology: Crossed by new link road.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: High

Hydrology / Flood Risk: Moderate

Geomorphology: Moderate

Water Quality: Moderate / Substantial

Unnamed ditch of Keithing Burn

Hydrology / Flood Risk: Medium

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: Runoff may be increased and faster than baseline conditions. Flood plain will be reduced by proposed slip roads.

Geomorphology: Crossed by new link road.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Slight

Geomorphology: Slight

Water Quality: Negligible

The Cast

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: Runoff may be increased and faster than baseline conditions.

Geomorphology: New crossing for roundabout and link road.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Negligible

Table 8.14: Summary of Potential Impacts During Operation – North Corridor Option 2

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Pinkerton Burn	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology and Flood Risk: Alterations to existing flow and flooding regime due to new crossing, and a greater impermeable area / more / faster runoff than baseline. Fluvial Geomorphology: One additional crossing. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Slight Geomorphology: Moderate Water Quality: Negligible
Brankholm Burn	Hydrology / Flood Risk: High Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: Surface water runoff from the road may discharge into Brankholm Burn. Possible alterations to existing flow and flooding regime due to new crossing, greater impermeable area / more / faster runoff than baseline. Fluvial Geomorphology: One additional crossing. Water Quality: Proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage; could result in a major shift from baseline due to discharge of untreated road runoff and accidental spillages, due to increased traffic loadings, sediment load, soluble and insoluble pollutants. Low dilution capacity of watercourse.	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: High	Hydrology / Flood Risk: Moderate / Substantial Geomorphology: Slight Water Quality: Moderate
Unnamed ditch (south of Masterton Junction)	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There could be alterations to existing flow and flooding regime due to new crossing, there would be greater impermeable area / more and faster runoff than baseline. Fluvial Geomorphology: One additional crossing. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Negligible
Keithing Burn	Hydrology / Flood Risk: Medium Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: Runoff may be increased and faster than baseline conditions. Fluvial Geomorphology: No direct impact as not crossed. Water Quality: Proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low / medium dilution capacity of watercourse.	Hydrology / Flood Risk: Low Geomorphology: Negligible Water Quality: High	Hydrology / Flood Risk: Slight Geomorphology: Negligible Water Quality: Moderate / Substantial

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Pinkerton Burn

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology and Flood Risk: Alterations to existing flow and flooding regime due to new crossing, and a greater impermeable area / more / faster runoff than baseline.

Fluvial Geomorphology: One additional crossing.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Slight

Geomorphology: Moderate

Water Quality: Negligible

Brankholm Burn

Hydrology / Flood Risk: High

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: Surface water runoff from the road may discharge into Brankholm Burn. Possible alterations to existing flow and flooding regime due to new crossing, greater impermeable area / more / faster runoff than baseline.

Fluvial Geomorphology: One additional crossing.

Water Quality: Proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage; could result in a major shift from baseline due to discharge of untreated road runoff and accidental spillages, due to increased traffic loadings, sediment load, soluble and insoluble pollutants. Low dilution capacity of watercourse.

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: High

Hydrology / Flood Risk: Moderate / Substantial

Geomorphology: Slight

Water Quality: Moderate

Unnamed ditch (south of Masterton Junction)

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There could be alterations to existing flow and flooding regime due to new crossing, there would be greater impermeable area / more and faster runoff than baseline.

Fluvial Geomorphology: One additional crossing.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Negligible

Keithing Burn

Hydrology / Flood Risk: Medium

Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: Runoff may be increased and faster than baseline conditions.

Fluvial Geomorphology: No direct impact as not crossed.

Hydrology / Flood Risk: Low

Geomorphology: Negligible

Water Quality: High

Hydrology / Flood Risk: Slight

Geomorphology: Negligible

Water Quality: Moderate / Substantial

Southern Route Corridor Options (Operation)

Impacts Common to Both Southern Route Corridor Options

8.4.47 Surface water runoff is proposed to outfall into Linn Mill Burn from both route corridor options (NGR NT11377864). Potential impacts on this watercourse as a result of road runoff discharge include:

Hydrology and Flood Risk: The routes do not cross Linn Mill Burn, but do run through its catchment area and could cause alterations to the runoff regime. There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Linn Mill Burn has been assigned low sensitivity and impacts on hydrology / flood risk have been assessed as low magnitude with a consequent Negligible significance.
Fluvial Geomorphology: Suspended sediment supplied from road drainage may be deposited on the bed of the watercourse. However the low volume of sediment and potential for dilution and downstream transfer means this would have an impact of Negligible significance on the fluvial geomorphology of the watercourse.
Water Quality: The proposed road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Potential decreased water quality resulting from road runoff carrying sediment load, soluble and insoluble pollution may occur and potential increased risk from accidental spillage. Low dilution capacity of watercourse. Due to the low sensitivity assigned to Linn Mill Burn, impacts on water quality have been assessed as high magnitude and therefore Moderate significance.

South Corridor Option 1

8.4.48 See Table 8.15 below for an assessment of potential impacts to affected watercourses during the operational phase of South Corridor Option 1.

South Corridor Option 2

8.4.49 See Table 8.16 below for an assessment of potential impacts to affected watercourses during the operational phase of South Corridor Option 2.

Table 8.15: Summary of Potential Impacts During Operation – South Corridor Option 1

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Swine Burn	Hydrology / Flood Risk: Medium Fluvial Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Flood plain will be affected. Fluvial Geomorphology: Two additional crossings and one modified crossing structure. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: High Water Quality: Low	Hydrology / Flood Risk: Slight Geomorphology: Moderate / Substantial Water Quality: Slight
Dolphington Burn	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Fluvial Geomorphology: One additional crossing. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Negligible
Niddry Burn	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: High	Hydrology and Flood Risk: There would be a greater impermeable area with potential for more and faster runoff. Fluvial Geomorphology: Modified crossing structure. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Moderate

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Swine Burn

Hydrology / Flood Risk: Medium

Fluvial Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Flood plain will be affected.

Fluvial Geomorphology: Two additional crossings and one modified crossing structure.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: High

Water Quality: Low

Hydrology / Flood Risk: Slight

Geomorphology: Moderate / Substantial

Water Quality: Slight

Dolphington Burn

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline.

Fluvial Geomorphology: One additional crossing.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Negligible

Niddry Burn

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: High

Hydrology and Flood Risk: There would be a greater impermeable area with potential for more and faster runoff.

Fluvial Geomorphology: Modified crossing structure.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Moderate

Table 8.16: Summary of Potential Impacts During Operation – South Corridor Option 2

Water Feature	Sensitivity	Impact Description Summary	Potential Impact (unmitigated)
Magnitude	Significance
Swine Burn at M9	Hydrology / Flood Risk: Medium Fluvial Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: Diversion could result in a different flow regime at the crossing of the M9. Greater impermeable area with the potential for more and faster runoff than baseline. The route runs through a large part of the catchment area of the Swine Burn and could interfere with existing runoff routes and flooding. Fluvial Geomorphology: Construction of two additional crossings and modifications to one existing crossing. Water Quality: Potential road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low / medium dilution capacity of watercourse.	Hydrology / Flood Risk: Medium Geomorphology: High Water Quality: High	Hydrology / Flood Risk: Moderate Geomorphology: Moderate / Substantial Water Quality: Moderate / Substantial
Swine Burn upstream of Humbie Reservoir	Hydrology / Flood Risk: Medium Fluvial Geomorphology: Medium Water Quality: Medium	Hydrology and Flood Risk: There is a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Fluvial Geomorphology: Construction of one additional crossing and modifications to one existing crossing. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Low	Hydrology / Flood Risk: Slight Geomorphology: Moderate Water Quality: Slight
Unnamed tributary of Swine Burn	Hydrology / Flood Risk: Medium Fluvial Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There is a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Fluvial Geomorphology: Construction of one additional crossing and modifications to one additional crossing. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: Medium Water Quality: Negligible	Hydrology / Flood Risk: Slight Geomorphology: Slight Water Quality: Negligible
Niddry Burn	Hydrology / Flood Risk: Low Fluvial Geomorphology: Medium Water Quality: High	Hydrology and Flood Risk: There is a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Fluvial Geomorphology: One modified crossing structure. Water Quality: Potential road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low / medium dilution capacity of watercourse.	Hydrology / Flood Risk: Low Geomorphology: Low Water Quality: High	Hydrology / Flood Risk: Negligible Geomorphology: Slight Water Quality: Substantial
Dolphington Burn	Hydrology / Flood Risk: Low Fluvial Geomorphology: Low Water Quality: Low	Hydrology and Flood Risk: There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline. Fluvial Geomorphology: Construction of two additional crossings and modification of one existing crossing. Water Quality: Impacts from diffuse pollution sources likely to be negligible.	Hydrology / Flood Risk: Low Geomorphology: High Water Quality: Low	Hydrology / Flood Risk: Negligible Geomorphology: Moderate Water Quality: Negligible

Water Feature

Sensitivity

Impact Description Summary

Potential Impact (unmitigated)

Magnitude

Significance

Swine Burn at M9

Hydrology / Flood Risk: Medium

Fluvial Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: Diversion could result in a different flow regime at the crossing of the M9. Greater impermeable area with the potential for more and faster runoff than baseline. The route runs through a large part of the catchment area of the Swine Burn and could interfere with existing runoff routes and flooding.

Fluvial Geomorphology: Construction of two additional crossings and modifications to one existing crossing.

Water Quality: Potential road drainage discharge may lead to siltation and indirect impacts on freshwater habitats. Decreased water quality resulting from untreated road runoff carrying sediment load, soluble and insoluble pollution may occur and increased risk from accidental spillage. Low / medium dilution capacity of watercourse.

Hydrology / Flood Risk: Medium

Geomorphology: High

Water Quality: High

Hydrology / Flood Risk: Moderate

Geomorphology: Moderate / Substantial

Water Quality: Moderate / Substantial

Swine Burn upstream of Humbie Reservoir

Hydrology / Flood Risk: Medium

Fluvial Geomorphology: Medium

Water Quality: Medium

Hydrology and Flood Risk: There is a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline.

Fluvial Geomorphology: Construction of one additional crossing and modifications to one existing crossing.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Low

Hydrology / Flood Risk: Slight

Geomorphology: Moderate

Water Quality: Slight

Unnamed tributary of Swine Burn

Hydrology / Flood Risk: Medium

Fluvial Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There is a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline.

Fluvial Geomorphology: Construction of one additional crossing and modifications to one additional crossing.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: Medium

Water Quality: Negligible

Hydrology / Flood Risk: Slight

Geomorphology: Slight

Water Quality: Negligible

Niddry Burn

Hydrology / Flood Risk: Low

Fluvial Geomorphology: Medium

Water Quality: High

Hydrology and Flood Risk: There is a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline.

Fluvial Geomorphology: One modified crossing structure.

Hydrology / Flood Risk: Low

Geomorphology: Low

Water Quality: High

Hydrology / Flood Risk: Negligible

Geomorphology: Slight

Water Quality: Substantial

Dolphington Burn

Hydrology / Flood Risk: Low

Fluvial Geomorphology: Low

Water Quality: Low

Hydrology and Flood Risk: There would be a greater impermeable area in the catchment area with the potential for more and faster runoff than baseline.

Fluvial Geomorphology: Construction of two additional crossings and modification of one existing crossing.

Water Quality: Impacts from diffuse pollution sources likely to be negligible.

Hydrology / Flood Risk: Low

Geomorphology: High

Water Quality: Low

Hydrology / Flood Risk: Negligible

Geomorphology: Moderate

Water Quality: Negligible

8.5 Potential Mitigation

8.5.1 The objectives of the mitigation measures outlined in this section are to prevent, reduce or offset the potential impacts described above. At this DMRB Stage 2 assessment of route corridor options, the detailed design (including watercourse crossings) has not been developed, and mitigation detail therefore cannot be accurately defined. The objective of this section is therefore to identify ‘standard’ or ‘anticipated’ mitigation taking cognisance of best practice, legislation and guidance. This mitigation is taken into account in the subsequent identification of residual impacts in Section 8.6 (Summary of Route Corridor Options Assessment), to provide a robust basis for comparative assessment and selection of a preferred route corridor option to be taken forward to DMRB Stage 3.

8.5.2 Adverse environmental effects are most likely to be experienced during the construction phase, as this is the period when there is most activity on site. However there is also potential for pollution and spillage events from vehicles during the operational phase through the everyday use of the road.

8.5.3 The objective of mitigation is to prevent, reduce or offset potential impacts. Mitigation would include those measures to convey surface water runoff from the road to receiving watercourses without detrimental effect on water quality, water quantity, associated ecosystems or the underlying groundwater (Chapter 7: Geology, Contaminated Land and Groundwater). It also includes measures to reduce impacts on geomorphological features that may arise from the installation of bridge piers, culverts and realignments, as well as those to be implemented to avoid impacts during the construction phase.

Potential Mitigation (Construction)

8.5.4 Measures to avoid, reduce or control pollution of surface water (and groundwater) would incorporate SEPA requirements and best practice on site to help avoid pollution release to watercourses. In particular, relevant SEPA Pollution Prevention Guidelines (PPGs) would be implemented and a Construction Environmental Management Plan (CEMP) would be produced.

8.5.5 Mitigation requirements for works in the vicinity of water features, incorporating SEPA PPG guidance, are summarised below:

control of suspended solid release using appropriate runoff and erosion controls;
appropriate storage of oils, fuels and chemicals, and identification of contingency plans for any accidental pollution incidents (such as spills);
undertaking potentially polluting activities (e.g. concrete batching and mixing) away from watercourses, ditches and surface water drains;
watercourse crossing works to be undertaken using appropriate methods to reduce the risk of pollution to the watercourse;
appropriate method of working for outfall construction including adherence to SEPA (2007) SG-28 Good Practice Guide: Construction of Outfalls; and
site sewage disposal to follow good practice and any service diversions to be carried out using good engineering practices.

8.5.6 Avoidance and reduction of construction impacts on watercourses would be achieved through best practice, which may include some or all of the following:

minimising the duration and spatial extent of works in the vicinity of watercourses and ensuring adequate sediment control measures are in place around the works;
progressive rehabilitation of exposed areas throughout the construction period as soon as possible after the work has been completed to reduce the risk of sediment release into the channel;
installation of temporary treatment ponds, where required, to ensure the protection of water quality throughout construction. Details regarding any temporary construction treatment ponds would be agreed with SEPA prior to commencement of construction. Guidance detailed in CIRIA C697 (2007) would be followed relating to temporary Sustainable Urban Drainage Systems (SUDS);
inspection and maintenance of all erosion controls weekly and after heavy rainfall; and
adherence to CIRIA C648 (2006) – Control of Water Pollution From Linear Construction Projects: Technical Guidance.

8.5.7 Groundwater Protection Zones (GPZ) can require specific mitigation requirements with regard to control of surface water pollution. However, as noted in Chapter 7: Geology, Contaminated Land and Groundwater), there are no GPZs established in the study area.

Potential Mitigation (Operation)

8.5.8 The drainage design for the proposed scheme would include mitigation measures in the form of SUDS to convey, attenuate, store and treat surface road runoff. SUDS measures would be used where appropriate and could include some or all of the following; filter drains, catch pits, swales, retention basins and treatment ponds (up to three in series which may include wet or dry ponds or a mixture). The design would be progressed at DMRB Stage 3, following detailed pollution and spillage calculations as part of the EIA.

8.5.9 Where SUDS are proposed, these would be designed in accordance with ‘The SUDS Manual’ CIRIA C697 (CIRIA, 2007); ‘Treatment of Highway Runoff using Constructed Wetlands’ (Environment Agency, 1998), and ‘Road Drainage and the Water Environment’, Volume 11, Section 3, Part 10 (The Highways Agency et al., 2006).

8.5.10 Outfall structures would be correctly positioned to limit the potential for scour around the culverts and designed with the aim of avoiding significant alteration to flow patterns. The outfall would not project out into the channel and would not be located where flow converges with river banks. Outfall design would comply with best practice, including CIRIA 697 (CIRIA, 2007) and SEPA (2007) SG-28 Good Practice Guide: Construction of Outfalls.

8.5.11 Water crossings would be in the form of bridges or culverts, designed to convey at least the 0.5% AEP event.

8.5.12 Where culverts are provided, the design would follow relevant good practice and guidance such as CIRIA (1997) Culvert Design Manual: Report 168; and SEPA (2007) SG-25 Best Management Practice: River Crossings. Where applicable, the proposed crossings would accommodate fish passage following guidance from ‘River Crossings and Migratory Fish: Design Guidance: A Consultation Paper for the Scottish Executive’ (SEERAD, 2000). The design of the proposed crossings would aim to ensure that there is minimal disruption to the existing flow regime of the affected watercourse.

8.5.13 Dependent on design of the proposed replacement bridge and any associated potential land claim from designated areas, there could be a need for provision of compensatory habitat.

8.6 Summary of Route Corridor Options Assessment

Northern Route Corridor Options

Hydrology and Flood Risk

8.6.1 In general there would be Negligible residual impact on flood risk due to the route corridor options. However, greater mitigation works would be required for North Corridor Option 2. Consequently, North Corridor Option 1 is the preferred route with respect to flood risk.

Geomorphology

8.6.2 For geomorphology it is difficult to determine the reduction in significance of the impact as at this stage the design is not as detailed as would be required for this determination. However, providing the proposed replacement bridge structure is sympathetically designed to consider the unique geomorphology of the estuary and, if necessary, coastal habitat compensation is provided, then it is considered that there would be only a Negligible adverse residual impact on coastal geomorphology. If land claim within the Firth of Forth is proposed as part of the scheme, the potential residual impact could be greater unless compensatory habitat is provided. The reduction in significance of impact on fluvial geomorphology would be largely dependent on the design details of proposed watercourse crossings and any proposed watercourse realignments.

8.6.3 North Corridor Option 1 would have a Slight residual impact on Pinkerton Burn, Keithing Burn and Negligible to Slight residual impact on an unnamed ditch of Keithing Burn and The Cast. North Corridor Option 2 would result in a Slight residual impact on Pinkerton Burn due to the construction of an additional crossing over this watercourse and a Negligible to Slight residual impact on Brankholm Burn and an unnamed ditch (south of Masterton Junction). Overall, geomorphological impact on watercourses would be similar for either northern route corridor option.

Water Quality

8.6.4 Due to the similarities of design between the two options, their associated risks and potential impacts on water quality would be similar. The risk of impacts however, can be considered to increase with the scale and complexity of construction works and operational road drainage. For example, a longer route with more crossings and road drainage is assessed as having a higher potential risk of impact on water quality.

8.6.5 North Corridor Option 1 and North Corridor Option 2 are both considered to have a Negligible to Slight residual impact during construction. Although North Corridor Option 1 crosses more watercourses (due to junction configuration), it is still considered on balance to have the lowest likely residual impact during construction as it is an online upgrade. Although North Corridor Option 2 would cross fewer watercourses, it has the potential to have indirect impacts on watercourses due to construction works associated with an offline alignment.

8.6.6 Similarly during operation, both northern route corridor options are considered to have a Negligible to Slight significance as, at this stage, they both have two road drainage discharges proposed. North Corridor Option 1 however, is a shorter route and as an online upgrade there may be the potential to improve existing road drainage discharges. North Corridor Option 1 is considered on balance to have the lowest likely residual impact during operation.

Southern Route Corridor Options

Hydrology and Flood Risk

8.6.7 From the assessments during both construction and operation for southern route corridor options, the residual impacts would be of Negligible significance. Slightly greater mitigation would be required for South Corridor Option 2. In terms of flood risk, therefore, South Corridor Option 1 is preferred.

Geomorphology

8.6.8 South Corridor Option 1 would have a Moderate residual impact on Swine Burn due to the requirement for two additional crossings, and a Negligible to Slight residual impact on other watercourses. South Corridor Option 2 would have a Moderate residual impact on Swine Burn due to the requirement for three additional crossings and a Slight residual impact on Dolphington Burn also due to a requirement for three additional crossings. In terms of geomorphology, South Corridor Option 1 has the lowest overall impacts.

Water Quality

8.6.9 Of the two southern route corridor options, South Corridor Option 1 is considered to have the lowest residual impact during construction (Negligible to Slight) as it would have impacts on the least number of watercourses. South Corridor Option 2 would require greater mitigation in order to achieve a Negligible to Slight impact on the water environment.

8.6.10 Similarly, during operation South Corridor Option 1 is considered to have the lowest residual impact (Negligible to Slight significance) as it has the least number of watercourses potentially impacted and one proposed road drainage discharge. South Corridor Option 2 would necessitate greater mitigation in order to give residual impacts of Negligible to Moderate significance.

8.7 Scope of Stage 3 Assessment

8.7.1 During the Stage 3 Assessment further baseline information will be collected. A more detailed assessment will be carried out using DMRB Volume 11 methodology unless otherwise agreed with statutory consultees. An outline of the scope of the assessments for hydrology and flood risk, coastal and fluvial geomorphology and water quality is given below.

Hydrology and Flood Risk

an assessment of the capacity of each crossing structure for the maximum design flow of 0.5% Annual Exceedance Probability (AEP) i.e. 1 in 200 year event;
assessment of the effects of crossing structures on water levels;
assessment of the impact on water levels of any road embankments within functional floodplains; and
proposals for mitigation measures and identifying where opportunities may exist to offset impacts.

Coastal Geomorphology

detailed desk study reviewing relevant literature, historic maps and aerial photography and other data sources;
detailed field survey; and
assessment of impacts and identification of mitigation measures and, where practicable, opportunities to offset the impacts of the proposed scheme.

Fluvial Geomorphology

detailed assessment of baseline characteristics of each watercourse including sediment regime, channel morphology and continuity of fluvial processes; and
assessment of impacts and proposals for mitigation measures and where practicable, opportunities to offset impacts.

Water Quality

assessment of the potential impact from suspended solids and accidental spillage (e.g. of oils or concrete) during construction;
estimation using methods based on DMRB, of copper and zinc concentrations within receiving watercourses immediately downstream of proposed highway discharge points;
calculation of risk of serious pollution from spillage of liquids from heavy good vehicles as a result of vehicular collision during operation; and
development of mitigation measures including appropriate pollution control facilities within the drainage design.

8.8 References

CIRIA (2006). Control of Water Pollution from Linear Construction Projects: Technical Guidance. CIRIA C648. Murnane, E., Heap, A. and Swain, A. ISBN 0-86-17-648-7.

CIRIA (2007). The SUDS Manual, CIRIA C697 Woods-Ballard, B., Kellagher, R., Martin, P., Jefferies, C., Bray, R. and Shaffer, P. ISBN 0-86017-697-5.

Institute of Hydrology (1999). Flood Estimation Handbook (FEH).

SEPA (2002). The Future for Scotland’s Water: Guiding principles on the technical requirements of the Water Framework Directive.

SEPA (2007).WAT-SG-25 Good Practice Guide: Construction of River Crossings

SEPA (2007b). WAT-SG-21 Environmental Standards for River Morphology

The Highways Agency et al. (2006). Design Manual for Roads and Bridges (DMRB). Volume 11, Section 3, Part 10. The Highways Agency, Scottish Executive Development Department, The National Assembly for Wales and The Department of Regional Development Northern Ireland.

The Water Environment (Oil Storage) (Scotland) Regulations 2006.

Water Framework Directive (2000/60/EC).