Proposed Rising Main, Findrassie, Elgin Hydrological Assessment - June 2021
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Proposed Rising Main, Findrassie, Elgin Hydrological Assessment June 2021
Proposed Rising Main, Findrassie, Elgin Hydrological Assessment Client: Barratt & David Wilson Homes North Scotland Document number: 9610 Project number: 675020 Status: FINAL Author: Eleanor Morrison & Jennifer Smith Reviewer: Martin Nichols Date of issue: 24 June 2021 Filename: 675020_Findrassie Rising Main Route_GWDTE Assessment EnviroCentre Limited Office Locations: Glasgow Edinburgh Inverness Aberdeen Registered Office: Craighall Business Park 8 Eagle Street Glasgow G4 9XA Tel 0141 341 5040 info@envirocentre.co.uk www.envirocentre.co.uk This report has been prepared by EnviroCentre Limited with all reasonable skill and care, within the terms of the Contract with Barratt & David Wilson Homes North Scotland (“the Client”). The report is confidential to the Client, and EnviroCentre Limited accepts no responsibility of whatever nature to third parties to whom this report may be made known. No part of this document may be reproduced or altered without the prior written approval of EnviroCentre Limited.
Barratt & David Wilson Homes North Scotland June 2021
Proposed Rising Main, Findrassie, Elgin; Hydrological Assessment
Contents
1 Introduction ................................................................................................................................................... 1
1.1 Terms of Reference ............................................................................................................................. 1
1.2 Scope of Report ................................................................................................................................... 1
1.3 Report Usage ....................................................................................................................................... 1
2 Baseline Information .................................................................................................................................... 3
2.1 Site Location......................................................................................................................................... 3
2.2 Topography .......................................................................................................................................... 5
2.3 Geology ................................................................................................................................................. 6
2.4 Environmental Designations ............................................................................................................... 7
2.5 River Basin Management Plan Waterbody Classification ............................................................... 7
2.6 Historic Review..................................................................................................................................... 8
2.7 Flooding ................................................................................................................................................ 9
2.8 Consultation .......................................................................................................................................... 9
2.9 Site Walkover ....................................................................................................................................... 9
2.10 Loch Spynie ........................................................................................................................................ 10
2.11 Conceptual Understanding............................................................................................................... 12
3 Proposed Development ............................................................................................................................. 14
4 Potential Impacts of Development ........................................................................................................... 15
4.1 Hydrology and Hydrogeology .......................................................................................................... 15
4.2 Water Quality ...................................................................................................................................... 17
5 Recommendations ..................................................................................................................................... 18
6 Conclusions ................................................................................................................................................ 19
References .......................................................................................................................................................... 20
Appendices
A Topographic Survey
B Site Photographs
C Design Drawings
D Cross Sectional Profiles
Figures
Figure 2-1: Site Location Plan ............................................................................................................................. 4
Figure 2-2: Topography ....................................................................................................................................... 5
Figure 2-3: Superficial Geology .......................................................................................................................... 6
Figure 2-4: Bedrock Geology .............................................................................................................................. 7
Figure 2-5 Roy Highland Map, 1747-1752. ...................................................................................................... 8
Figure 2-6: Catchment Areas ............................................................................................................................ 11
Figure 2-7: Hydrological Features .................................................................................................................... 12
Figure 3-1: Cross Sectional profile of the proposed excavation into the railway embankment .............. 14
Figure 4-1: Cross Sections ................................................................................................................................ 16
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1 INTRODUCTION
1.1 Terms of Reference
EnviroCentre Ltd was commissioned by Barratt & David Wilson Homes North Scotland to undertake a
hydrological assessment for a proposed rising main route to the east of the Findrassie E1-E4 housing
development site in Elgin, Moray. The proposed rising main route extends approximately 5.2km from
the east side of the A941 road towards Inchbroom Road (B9103) in the north east. Part of the route is
in close proximity to Loch Spynie and the associated wetlands which are designated as a Site of
Special Scientific Interest (SSSI), Special Protection Area (SPA) and RAMSAR site.
As recommended by NatureScot, the assessment will focus on the potential hydrological impacts of
the development on potential Groundwater Dependent Terrestrial Ecosystems (GWDTE), which are
highlighted as fen, swamp, and wet woodland habitats associated with Loch Spynie.
The current study has been undertaken with reference to the Ecological Constraints Report for the
development (EnviroCentre report 9514, dated March 2021), and both will inform the ongoing Habitats
Regulations Appraisal for the site.
1.2 Scope of Report
The aim of the study is to appraise the potential impacts of the proposed development on local
groundwater conditions, with a focus on the potential GWDTE which have been highlighted as fen, wet
woodland and swamp surrounding Loch Spynie. A review of baseline information will be undertaken
together with topographic analysis, in order to develop a conceptual understanding of the local
hydrological environment and influences on the potential GWDTE understood to be present. Design
information will be reviewed to assess the potential impacts of the development on local hydrology and
potential GWDTE, and outline recommendations for potential mitigation will be made as appropriate. It
is essential that the design and construction of the development should avoid negative impacts upon
the functioning and status of these features.
The assessment is made with reference to relevant guidance, particularly Scottish Environment
Protection Agency (SEPA) Land Use Planning System Guidance Note 31 (Guidance on Assessing the
Impacts of Development Proposals on Groundwater Abstractions and Groundwater Dependent
Terrestrial Ecosystems).
1.3 Report Usage
The information and recommendations contained within this report have been prepared in the specific
context stated above and should not be utilised in any other context without prior written permission
from EnviroCentre.
If this report is to be submitted for regulatory approval more than 12 months following the report date,
it is recommended that it is referred to EnviroCentre for review to ensure that any relevant changes in
data, best practice, guidance or legislation in the intervening period are integrated into an updated
version of the report.
Whilst the Client has a right to use the information as appropriate, EnviroCentre Ltd retain ownership
of the copyright and intellectual content of this report. Any distribution of this report should be
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Proposed Rising Main, Findrassie, Elgin; Hydrological Assessment
controlled to avoid compromising the validity of the information or legal responsibilities held by both
the Client and EnviroCentre Ltd (including those of third party copyright). EnviroCentre do not accept
liability to any third party for the contents of this report unless written agreement is secured in
advance, stating the intended use of the information.
EnviroCentre accept no liability for use of the report for purposes other than those for which it was
originally provided, or where EnviroCentre have confirmed it is appropriate for the new context.
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2 BASELINE INFORMATION
2.1 Site Location
The location of the proposed rising main route is shown on Figure 2-1. It links to the proposed housing
development site beside the A941 road at national grid reference (NGR) NJ 21798 65185, and extends
in a north east direction to a point to the south of Lossiemouth, along Inchbroom Road (B9103) at NGR
NJ 23661 69347.
The proposed rising main extends for approximately 5.2km, mainly along the route of a former railway
line, much of which is formed as a raised embankment. This route currently provides local agricultural
access and is used as a public pathway. The southernmost 1.4km of the route is diverted away from
the railway route, to run along a local access road towards the housing development site.
The route of the proposed rising main passes through a range of land uses including coniferous
woodland, arable agriculture, wetland and wet woodland. It crosses various small watercourses, and
the Spynie Canal which flows in a north-east direction before discharging into the sea at Lossiemouth.
Loch Spynie, which is a registered as a Controlled Reservoir under the Reservoirs (Scotland) Act
2011, is located to the east of the proposed rising main route and to the south of the canal. The loch
and the associated wetlands surrounding it are designated as a Site of Scientific Interest (SSSI),
Special Protection Area (SPA) and a Ramsar site.
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Lossiemouth
B9103 Road
A941 Road
Site of proposed housing
development, Elgin
Figure 2-1: Site Location Plan
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2.2 Topography
A topographic survey specific to the proposed route was carried out by Goodson Associates in May
2020, which is provided in Appendix A. The topography of the surrounding area has been represented
using a 5m resolution Digital Terrain Model (DTM; Ordnance Survey Terrain 5), shown on Figure 2-2.
The rising main route passes through a relatively flat and low-lying landscape, known locally as the
‘Laich O’ Moray’. The majority of the route is perched above the surrounding landscape, upon the
raised former railway embankment. Some sections, particularly towards the north and south, conform
more closely to adjacent ground levels.
As it passes Loch Spynie, the top level of the embankment varies between approximately 2.5 and 3.5
metres Above Ordnance Datum (mAOD). Ground levels around Loch Spynie are relatively flat and low-
lying (e.g. 0.8 to 1.5mAOD to the northwest) although to the south east levels rise to a maximum of
14mAOD. Steeper ground is located along the southern section of the route, rising to 40 mAOD
(Spynie Hill).
Figure 2-2: Topography
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2.3 Geology
British Geological Survey (BGS) Superficial Geology maps (1:50,000 scale) identify the surrounding area
as being composed of several deposits as shown in Figure 2-3. The southern portion of the route is
located on Glaciofluvial Ice Contact Deposits, whilst Lacustrine Deposits are found around Loch Spynie.
In the northern part of the route the underlying superficial geology is comprised of Raised Marine and
Storm Beach Deposits. To the east there are pockets of Alluvium associated with the River Lossie.
Figure 2-3: Superficial Geology
The BGS (1:50,000) Bedrock Geology maps identify the surrounding area as being underlain primarily
by sandstone (Figure 2-4). The underlying bedrock in the northern part of the route derives from the
Kingsteps Sandstone Formation, with Rosebrae Beds Sandstone to the south. There are also some linear
formations traversing the southern part of the route, comprised of sandstone, siltstone, chert, limestone
and Lossiemouth sandstone.
The underlying aquifer is classified as being moderately productive. It is designated as class 2B,
meaning that virtually all flows are through all fractures and discontinuities. The aquifer is multi-layered,
with low yields, except for where it has been historically disturbed by mining (Scottish Government,
2014).
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Figure 2-4: Bedrock Geology
2.4 Environmental Designations
Loch Spynie is designated as a Site of Special Scientific Interest (SSSI), a Special Protection Area
(SPA) and a Ramsar site, for the protection of the loch, surrounding wetlands and wildlife. The loch is
one of very few large eutrophic (nutrient rich) water bodies in northern Scotland. The open water
supports a range of diverse flora (dense reed beds) and the loch is surrounded by a number of
protected wetland typologies including fen, swamp and wet woodland. This mosaic of habitats support
a range of breeding birds and also internationally important numbers of roosting Icelandic greylag
geese.
A small area of ancient woodland is located in close proximity to the southern extent of the route, and
the Oakenhead Wood is located approximately 0.5km north-east of the proposed route.
The Spynie Quarry SSSI (cited for fossilised reptiles) is also located in close proximity to the southern
part of the route (at Spynie Hill).
2.5 River Basin Management Plan Waterbody Classification
The Spynie Canal is currently classified as having Good status, with high water quality and a good
classification in terms of water levels and flows (ID: 23026) (SEPA, 2015). It is designated as an
artificial waterbody. This is the only surface waterbody classified within the study area.
The Lossiemouth Coastal (ID: 150813) and Elgin (ID: 150637) groundwater bodies are classified as
Poor, due to diffuse pollution, and a Nitrate Vulnerable Zone has been designated to protect them from
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further pollution pressures. The Lossiemouth Coastal groundwater body is also classified as Poor in
terms of water flows and levels, due to commercial abstractions.
2.6 Historic Review
A review of historic maps available from the National Library of Scotland was undertaken, and further
accounts have been provided through consultation. The Roy Highlands map of 1747-1752 (Figure
2-5) highlights that Loch Spynie was historically part of a much larger waterbody; a loch extending into
the areas north and west of its current extent. It discharged into the River Lossie and would be likely to
be tidally influenced. Land drainage for agriculture is understood to have been undertaken since this
period.
Figure 2-5 Roy Highland Map, 1747-1752.
Reproduced with the permission of the National Library of Scotland
The Spynie Canal was built between 1808 and 1812 to a plan prepared by Thomas Telford, with some
reconstruction required around 1860, following damage by the ‘Muckle Spate’ of 1829, when the River
Lossie burst its banks. The Morayshire Railway Line was built in 1851-52. Ordnance Survey Six Inch
mapping from 1870 shows these features, together with an extensive land drainage network, which
remains in place to date. The design of the current loch also dates from this period. On the 1870 map
it appears to be a similar size and extent to the current day, and was surrounded by wetland vegetation
(National Library of Scotland, n.d.). The presence of sluices at that time indicates a degree of active
water level management. There was formerly a west embankment running parallel to the railway
embankment, but this was breached at some time around 1990. The loch is now bounded at the west
side by the disused railway line, such that the embankment forms one of the dams impounding the
reservoir.
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2.7 Flooding
A review of the SEPA (Scottish Environment Protection Agency) Flood maps suggests that there is a
risk of coastal flooding during a 1 in 200 year event, to the north of route. Fluvial (river) flooding during
a 1 in 200 year scenario is predicted to occur around Loch Spynie and the area extending to the west.
There is also a relatively extensive risk of surface water flooding across low-lying areas. No risk of
groundwater flooding is indicated.
SEPA Reservoir Inundation mapping indicates a risk of flooding to the north-east of the loch, in the
event of an extreme flood event or structural failure. Consultation with the Supervising Engineer for
Loch Spynie revealed that there had been noticeable flooding of Loch Spynie in 1892 as well as 1997
and 2002. It was stated that:
“In severe flood events, the River Lossie overtops and then breaches agricultural floodbanks
downstream of Elgin and water flows into the loch via the overflow. This is likely to have occurred on a
number of occasions between 1829 and 1997, but I have no specific information.”
2.8 Consultation
A consultation response from NatureScot in relation to the proposed development was provided at the
outset of the study, dated 13th May 2021. The relevant recommendations are summarised as follows:
• Consult with Loch Spynie’s Reservoir Manager and Engineers to obtain information and
opinion on the proposed development.
• It is important to ensure that any excavation work along the length of this embankment will not
lead to any direct hydrological changes that could affect the functioning of the wetlands across
the site, or on the status of the designations.
• A suitable range of appropriate mitigation measures should be designed and implemented to
prevent indirect effects arising from pollution, littering, biosecurity, adverse weather etc.
As part of this study, the Reservoir Supervising Engineer and the land owner (Pitgaveny Estates) were
consulted, e.g. to establish design information on the reservoir and embankments, outlet controls and
management activities, as well as any history of flooding or drought events. A response was obtained
from Reservoir Supervising engineer on 7th June 2021 via email, and the landowner was consulted by
phone on 16th June. No design drawings are available, but useful descriptive accounts were provided
on the structure, functioning and management of the reservoir.
Water levels in the loch are visually inspected weekly, and for the most part outflows through the
reservoir sluice are passive. It was noted that if the water level in the loch is reduced, this could give
birds access to shot from historic wildfowling and result in lead poisoning.
Through discussions with the landowner, it was highlighted that the Spynie Canal is maintained by the
‘Heritors of the Spynie Canal’, a group of local landowners who are responsible for the maintenance of
the canal and own it to the depth of the solum. Below this, the ground is owned by the adjacent
landowners.
2.9 Site Walkover
A site walkover was undertaken by EnviroCentre on 9th June 2021, during a period of warm, dry
weather. This survey covered the route of the railway embankment, to examine local waterbodies, the
railway embankment, ground conditions, visible drainage features and indicators of groundwater
influence. Site photographs can be found in Appendix B.
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In the vicinity of Loch Spynie, water levels to the east of the raised embankment (within the reservoir)
were noted to be approximately 1.75m below the crest of the raised embankment; while in the wet
woodland to the west the water surface was significantly lower (visually estimated to be over 2m below
the crest), indicating that the embankment represents an relatively impermeable barrier to hydrological
continuity. Similarly, the Spynie Canal was noted to form a distinct linear barrier to potential surface
and subsurface flow routes.
The site walkover also included inspection of some drainage ditches along the route of the raised
embankment, which were generally noted to be relatively deep, with sluggish water flowing at
moderate depth. In two ditches towards the north of the proposed route (NGR NJ 23506 68085 and NJ
23564 68719) the water was noted as having a visible blue, milky colouration and a strong odour. This
was identified as a bloom of blue-green algae (BGA), which can be toxic to people and wildlife. BGA
are an indicator of relatively high nutrient levels, and are generally found where water is relatively
warm and stagnant. Site observations indicated that the milky appearance of the water was due to
suspended solids originating from field drains and overland runoff.
Loch Spynie is also known to be highly eutrophic, with high levels of phosphate, nitrate and ammonia;
and it is understood that this is reflected in the quality of the associated groundwater.
2.10 Loch Spynie
2.10.1 Hydrology
Loch Spynie is a Controlled Reservoir under the Reservoirs (Scotland) Act 2011. The reservoir’s
supervising engineer confirmed that the railway embankment forms one of the dams impounding the
loch, although contemporary plans of the reservoir, or of the structural composition of the railway
embankment are not available. The landowner gave a descriptive account of the embankment,
informed through previous excavations of the track further to the north, and mentioned that clay had
been present. Together with the fact that water levels were notably different on either side of the
embankment on the day of the walkover survey, it is assumed that there is a relatively impermeable
layer or core within the embankment.
Flood Estimation Handbook (FEH) catchment delineation shows that an area of 7.11km2 drains into
Loch Spynie and the surrounding wetland area, and a smaller sub-catchment 0.65km2 drains to the
wetland to the west of the loch, as shown in Figure 2-6. These two catchments are artificially separated
by the disused railway embankment. The average annual rainfall for the catchments is 648mm.
The main inflow to the loch is a small unnamed watercourse which flows through Findrassie Wood to
the southwest, discharging into the loch’s southern end (Figure 2-7). Additional sources include direct
rainfall, surface water runoff from the surrounding wetland and seepage from groundwater. The
outflow of the loch is controlled by a weir penstock with an overflow pipe discharging into the Sypnie
Canal to the west. The loch typically sits at or above the outflow level.
There are also a number of drainage ditches within the surrounding wetland area which are
approximately between 0.5m and 1.0m deep. These drainage ditches act as a pathway for water to
travel within the wetland areas, and will maintain a general lowering of groundwater levels, whilst also
enhancing interchanges between surface and groundwater sources.
The wetland surrounding the loch is primarily comprised of fen, wet woodland and swamp habitats.
These were identified as potential Groundwater Dependant Terrestrial Ecosystems (GWDTE) in a
previous study undertaken by EnviroCentre (EnviroCentre report 9514, dated March 2021). Through
site observations and interpretation of the available baseline data, it is considered likely that these
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habitats will have a relatively high degree of interaction with groundwater. To an extent this interaction
will be artificially enhanced by the embankments and other modifications, but nevertheless the
groundwater present will play a role in supporting the current functioning of the ecosystems.
Figure 2-6: Catchment Areas
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Figure 2-7: Hydrological Features
2.10.2 Water Quality
Loch Spynie is one of very few large eutrophic water bodies in northern Scotland. High levels of
phosphate and nitrate were identified within Loch Spynie and the surrounding wetlands in a study
carried out by EnviroCentre (EnviroCentre, 2015). Elevated nutrient conditions are likely a
consequence of natural conditions (geology and soils) combined with arable, horticultural and
suburban land uses in the catchment, as well as high nutrient input from bird assemblages present.
2.11 Conceptual Understanding
Interpretation of the available information has led to a conceptual understanding of the hydrological
functioning of Loch Spynie and the surrounding wetlands, and also of the wider study area.
As described in section 2.6, an extensive programme of land drainage and watercourse engineering
has taken place since the 16th century, likely leading to a general lowering of the water table across
much of this low-lying landscape. The railway embankment and Spynie canal both represent
significant barriers to hydrological continuity, particularly in the vicinity of Loch Spynie, where
differential water levels are evident on either side of the embankment.
The loch itself is a remnant of a far larger natural waterbody, and has become contained within a series
of engineered structures. It is considered likely that water levels within the reservoir, along with the
groundwater associated with it, may vary independently of water levels beyond the embankments.
The same is likely to be true of the canal, which is understood to rise and recede in response to heavy
rainfall more rapidly than levels in the adjacent loch and wetlands.
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Otherwise, a relatively high degree of interchange between surface water bodies and shallow
groundwater is expected in this relatively flat and low-lying landscape. Fen, wet woodland and swamp
areas in the vicinity of Loch Spynie particularly to the west and north, are therefore likely to be fed by
both groundwater and surface water sources. Localised exchanges of surface and ground water will
be enhanced by drainage features and impeded by linear embankments and impounding structures.
Any significant changes to these features would have the potential to alter local flow paths and
hydrological functioning, with potential consequences on associated habitat distribution.
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3 PROPOSED DEVELOPMENT
Design drawings for the proposed Development can be found in Appendix C. Rising main works will
comprise the installation of two pipelines 180mm and 110mm in diameter laid on average at 1.2m
depth within the former railway line and general farm tracks (Figure 3-1). The installation will progress
section by section along the length of the route. It will comprise typical open track excavation (1.2m
deep x 0.8m wide) and will be backfilled with imported sand bedding and excavated arisings. It is
understood that the construction works will be restricted to the width of the track.
Figure 3-1: Cross Sectional profile of the proposed excavation into the railway embankment
Where the route is required to cross a watercourse, the pipeline will be directionally drilled below the
watercourse. The canal crossing is under design at the time of writing. Initial plans were to form a
suspended pipe crossing, although directional drilling is also being explored.
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4 POTENTIAL IMPACTS OF DEVELOPMENT
In order to maintain the local hydrological processes and water quality required to sustain the
functioning of the protected wetland habitats and GWDTE surrounding Loch Spynie, it is important that
the potential impacts of the proposed development are assessed, and mitigated appropriately where
required. Potential impacts on hydrology, hydrogeology and water quality are highlighted in this
section.
4.1 Hydrology and Hydrogeology
In light of the baseline assessment and conceptual understanding, a review of the proposed
development design has been undertaken to assess the potential impacts on the storage and flow of
both surface and groundwater.
The following potential impact mechanisms have been given consideration:
1. Excavation may come into contact with groundwater, altering its local distribution, or
potentially requiring pumping during construction.
2. The permeable sand bedding of the trench may become a preferential flow route for shallow
groundwater or floodwater, resulting in flow path diversion along the linear feature.
3. Depending upon the nature of the structure, excavation into the railway embankment may
have potential to increase its permeability (with implications upon its function in terms of
reservoir design and inducing a change in water levels on either side of the structure).
4. The buried pipeline has potential to impede shallow groundwater flow and storage processes.
5. Physical damage to the structures or functioning of field drainage networks.
6. Directional drilling below watercourses has potential to impact upon local hydromorphological
processes within the channel, and disrupt flow paths through the hyporheic zone (permeable
sediments beneath and alongside the channel bed, where there is mixing of shallow
groundwater and surface water).
For the majority of the proposed pipeline route, the depth of the excavation (1.2m) will be highly
unlikely to come into direct or close contact with groundwater, particularly where it passes through the
raised embankment which is perched above the surrounding landscape and is likely to be composed
of compacted, low permeability materials; and where relatively deep drainage ditches maintain the
water table at a low level relative to the ground surface.
In the vicinity of Loch Spynie, where impounding features are present, there is more potential for
groundwater levels to sit closer to the ground surface, particularly over winter or following flood
events.
In order to assess the potential for the excavation to impact on groundwater levels, seven cross-
sections were extracted from the 5m DTM using 3D Analyst tools in ArcGIS (Figure 4-1). These were
supplemented by more accurate elevations taken from the topographic survey along the track. Five
cross-sections were taken in the areas surrounding the wetland (XS2- XS6), with one further to the
north (XS1) and one to the south (XS7) of Loch Spynie. The cross-sectional profiles are given in
Appendix D.
The analysis shows ground levels in the wetland and surrounding areas in comparison to the height of
the railway embankment. Around Loch Spynie the railway embankment varies between at least 1.3m
and 2.4m above the surrounding ground levels. It is important to note that that actual ground surface
levels are likely to be lower than shown, due to inaccuracies in the remotely sensed elevation data
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where dense vegetation cover and the embankment are present. It is also noted that the drainage
ditches flanking parts of the railway embankment are not represented in the available topographic
data.
XS1 and XS7 are both located where the railway track has been formed within shallow localised
cuttings. These areas were noted to be relatively well drained and the water table is likely to sit at
significant depth.
At XS6 additional analysis has been carried out as differential water level estimates were obtained on
either side of the embankment during the site visit in this vicinity. Water levels were estimated to be
between 1.75m (east) and >2m (west) below the crest of the railway embankment. An excavation to a
depth of 1.2m would therefore be estimated to be approximately 0.6m or more above the local water
levels under typical conditions, and unlikely to have a direct impact.
Figure 4-1: Cross Sections
If the permeability of the railway embankment were to be affected by the excavation, this could result
in an alteration to water levels on either side of the embankment, with potential consequences on
habitat functioning and distribution over the long term. This risk is considered to be low. Further
consultation with those responsible for the reservoir and a test excavation may reveal more useful
information to support this.
The pipes themselves are narrow in diameter therefore they should have a minimal impact on the
storage or flow of groundwater, whether along the embankment (where materials are unlikely to allow
groundwater ingress), or below the channel bed.
Overall, the risk of physical alterations to local hydrological and hydrogeological processes is
considered to be low.
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4.2 Water Quality
The following potential water quality impacts have been identified during the construction process:
1. Release of contaminated materials from the railway embankment into the water environment.
2. Release of sediment-laden runoff into watercourses through construction activities.
3. Accidental pollutant leakages e.g. fuel spills.
4. Disturbance of contaminated bed materials at the base of watercourses by directional drilling.
No information is available to suggest that historic contaminated materials are present in the
embankment or channels, however it would be conservative to assume that may be the case, and to
minimise disturbance where possible. No formal design information is available to indicate the
materials used in the structure, although through consultation with the landowner, it is understood that
the sleepers were originally laid upon cinder, rather than standard ballast material. Previous
excavations had also indicated the presence of clay.
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5 RECOMMENDATIONS
The potential for negative impacts upon the water environment may be avoided or minimised through
careful design and sensitive construction methods. The following outline recommendations are made
to support the ongoing development of design and construction management plans:
1. Follow SEPA guidelines on pollution prevention.
2. Limit construction activities to a defined construction corridor along the embankment / agreed
working areas.
3. Minimise surface water runoff into watercourses or wetland areas to minimise release of
suspended solids or soluble contaminants e.g. using buffers / silt fences / bunds, as
appropriate.
4. Construction should be phased in sections, so that excavation, installation, backfilling and
reinstatement will be a continuous process.
5. Construction methods should incorporate an adaptive approach in the event that excavations
encounter sensitive features such as groundwater, impermeable structures within the
embankment, or potentially contaminated materials.
6. If significant, distinct layers of materials are present in the embankment, where practicable
these should be separately handled through excavation, storage, backfilling and
reinstatement.
7. If further investigation indicates that there is potential for the pipeline route to become a
preferential conduit for flow of groundwater or floodwater (particularly in the vicinity of the
loch), impermeable bunds at intervals along the trench may be used to limit this effect.
8. Buried watercourse crossings should be formed following best practice guidance set out in
‘Engineering in the water environment: good practice guide - River crossings’, SEPA 2010,
and in compliance with the Water Environment (Controlled Activities) (Scotland) Regulations
(2011).
9. Careful storage of excavated materials which have potential for contamination (e.g. storage in
approved hardstanding area, minimise time of storage, cover stockpiles with plastic sheeting).
10. Controlled offsite disposal of any excess spoil.
Project engineers should continue to consult with the reservoir engineer and manager on design and
construction methods. These parties have a responsibility to maintain the safety of the reservoir and
may be able to provide additional information and advice. The Heritors of the Spynie Canal should also
be consulted in relation to the proposed pipe crossing.
18Barratt & David Wilson Homes North Scotland June 2021
Proposed Rising Main, Findrassie, Elgin; Hydrological Assessment
6 CONCLUSIONS
To support the planning process for a proposed rising main route between Elgin and Lossiemouth, a
hydrological assessment has been undertaken. The route passes through the low-lying ‘Laich O’
Moray’ area, which has an extensive history of land drainage and water engineering.
The area around the Loch Spynie Reservoir and Spynie Canal have been identified as having the most
potential for impacts upon the water environment, although the potential likelihood and magnitude of
hydrological impacts is considered to be low, particularly where the pipeline will predominantly be
perched within a raised embankment above the surrounding landscape and typical water levels.
Mitigation measures have been recommended for the design and construction phase to neutralise or
minimise any potential negative impacts upon the local water environment. Assuming that these are
adopted appropriately, it is concluded that the proposed development is unlikely to impact upon the
hydrological functioning of the reservoir, sensitive wetland habitats or GWDTE; and the current status
of environmental designations and waterbody classifications will be unaffected.
19Barratt & David Wilson Homes North Scotland June 2021
Proposed Rising Main, Findrassie, Elgin; Hydrological Assessment
REFERENCES
Envirocentre Ltd (2015). Investigation of Standing Water and Wetland SSSIs thought to be under
Diffuse Pollution Pressure: Loch Spynie. Scottish Natural Heritage Commissioned Report.
National Library of Scotland (n.d.). Georefernced Maps. Retrieved from https://maps.nls.uk/
Scottish Government (2014, June). Scotland’s Environment. Scottish Government. Retrieved from
https://www.environment.gov.scot/media/1185/climate-climate.pdf
SEPA (2015). Water environment hub: Scotland River Basin District. Retrieved from
http://www.sepa.org.uk/data-visualisation/water-environment-hub/?riverbasindistrict=Scotland
20Barratt & David Wilson Homes North Scotland June 2021 Proposed Rising Main, Findrassie, Elgin; Hydrological Assessment APPENDICES
Barratt & David Wilson Homes North Scotland June 2021 Proposed Rising Main, Findrassie, Elgin; Hydrological Assessment A TOPOGRAPHIC SURVEY
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