The River AlmondStructural Examination
and Silt Surveys
Summary Report
October 2014
Rivers and Fisheries Trust Scotland
319034 BNI SNI 001 A
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22 October 2014
The River AlmondStructural Examination and Silt Surveys
Summary Report
The River Almond Structural Examination and Silt Surveys
Summary Report
October 2014
Rivers and Fisheries Trust Scotland
Mott MacDonald, Caledonian Exchange, 3rd Floor, 19A Canning Street, Edinburgh EH3 8EG, United Kingdom
T +44 (0)131 221 2300 F +44 (0)131 229 3735 W www.mottmac.com
RAFTS Suite 1F40 2 Commercial Street Edinburgh EH6 6JA
River Almond Structural Examination and Silt Surveys Summary Report
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Revision Date Originator Checker Approver Description Standard0 01/09/2014 L Mair K Keast A Martin Issue for Client comments Draft
1 22/10/2014 K Young K Keast A Martin Update with client comments
Issue and revision record
This document is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose.
We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties.
This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it.
River Almond Structural Examination and Silt Surveys Summary Report
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Chapter Title Page
Executive Summary i
1 Introduction 1
1.1 Background _______________________________________________________________________ 1 1.2 Purpose and Structure of Report _______________________________________________________ 1 1.3 Site Location and Description __________________________________________________________ 2
2 Scope and Methodology 5
2.1 Scope of Works ____________________________________________________________________ 5 2.2 General Methodology for Ground and Silt Investigation ______________________________________ 6 2.2.1 Geotechnical Testing ________________________________________________________________ 6 2.2.2 Contamination Testing _______________________________________________________________ 6 2.3 General Methodology for Structural Surveys of Weir ________________________________________ 7 2.4 Utilities Survey _____________________________________________________________________ 7 2.5 Topographic Survey _________________________________________________________________ 7 2.6 Level 3 Flood Risk Assessment ________________________________________________________ 8 2.7 Invasive Bridge Inspections and Scour Assessment ________________________________________ 9 2.7.1 Scour Investigations _________________________________________________________________ 9 2.8 Environmental survey and management ________________________________________________ 10
3 Peggies Mill Weir 11
3.1 Ground Conditions and Silt Deposition __________________________________________________ 11 3.2 Contamination ____________________________________________________________________ 12 3.3 Structural Condition of Weir __________________________________________________________ 13 3.4 Ecology __________________________________________________________________________ 13 3.5 Topographic and Utilities Surveys _____________________________________________________ 14 3.6 Flood Risk _______________________________________________________________________ 14
4 Dowies Weir 16
4.1 Ground Conditions and Silt Deposition __________________________________________________ 16 4.2 Contamination ____________________________________________________________________ 17 4.3 Structural Condition of Weir __________________________________________________________ 17 4.3.1 Bridges __________________________________________________________________________ 19 4.4 Ecology __________________________________________________________________________ 20 4.5 Topographic and Utilities Surveys _____________________________________________________ 20 4.6 Flood Risk _______________________________________________________________________ 21 4.7 Scour Assessment _________________________________________________________________ 22
5 Mid Calder Weir 24
5.1 Ground Conditions and Silt Deposition __________________________________________________ 24 5.2 Contamination ____________________________________________________________________ 25 5.3 Structural Conditions _______________________________________________________________ 25
Contents
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5.4 Utilities __________________________________________________________________________ 26
6 Rugby Club Weir 27
6.1 Ground Conditions and Silt Deposition __________________________________________________ 27 6.2 Contamination ____________________________________________________________________ 28 6.3 Structural Condition of Weir __________________________________________________________ 28 6.4 Ecology __________________________________________________________________________ 30 6.5 Utilities __________________________________________________________________________ 30
7 Howden Bridge Weir 31
7.1 Ground Conditions and Silt Deposition __________________________________________________ 31 7.2 Contamination ____________________________________________________________________ 32 7.3 Structural Condition of Weir __________________________________________________________ 32 7.4 Bridges __________________________________________________________________________ 34 7.5 Ecology __________________________________________________________________________ 35 7.6 Utilities __________________________________________________________________________ 36 7.7 Flood Risk _______________________________________________________________________ 36 7.8 Scour ___________________________________________________________________________ 37
8 Kirkton Weir 39
8.1 Ground Conditions and Silt Deposition __________________________________________________ 39 8.2 Contamination ____________________________________________________________________ 40 8.3 Structural Condition of Weir __________________________________________________________ 40 8.4 Ecology __________________________________________________________________________ 41 8.5 Utilities __________________________________________________________________________ 41
9 Seafield Weir 43
9.1 Ground Conditions and Silt Deposition __________________________________________________ 43 9.2 Contamination ____________________________________________________________________ 44 9.3 Ecology __________________________________________________________________________ 44 9.4 Utilities __________________________________________________________________________ 44
10 Benefit-Risk Ranking Register 45
10.1 Options __________________________________________________________________________ 45 10.2 Summary of Approach to Risk Ranking _________________________________________________ 45 10.3 Risk Ranking _____________________________________________________________________ 46
11 Findings and Recommendations 48
11.1 Key Findings ______________________________________________________________________ 48 11.2 Recommendations and Further Work ___________________________________________________ 48
12 References 50
Appendices 52
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Appendix A. Contamination Testing Results ________________________________________________________ 53
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River Almond Structural Examination and Silt Surveys Summary Report
Introduction
The River and Fisheries Trusts of Scotland (RAFTS), in partnership with the Scottish Environmental
Protection Agency (SEPA), are financing a project to assess the feasibility of improving fish passage at
seven weirs on the River Almond in order to help improve the status of the water body in accordance with
the Water Framework Directive (WFD) requirements. These weirs are Peggies Mill, Dowies Mill, Mid
Calder Weir, Rugby Club Weir, Howden Bridge Weir, Kirkton Weir and Seafield Weir.
Mott MacDonald Limited was commissioned by RAFTS in November 2013 to undertake investigations to
assess the following key risks:
� Sediment mobilisation, including potentially contaminated sediment;
� Unknown construction of weirs;
� Impact of weir removal on upstream bridges; and
� Impact on flood risk at 3 vulnerable sites.
Approach
This report summarises the findings of the site surveys and presents the conclusions of the flood risk
assessments undertaken for the Peggies, Dowies and Howden Bridge sites and the scour assessments
undertaken for the bridges upstream of Dowies Weir and Howden Bridge Weir. This report is supported by
site specific Structural Examination and Silt Survey reports which provide further detail of the surveys and
investigations undertaken at each site. This summary is also supported by the flood risk assessment
reports for Cramond Weirs (Dowies and Peggies) and Howden Bridge Weir. As part of a study undertaken
by Atkins in 2011, restoration options were identified for each site and the risk-benefit of each option
assessed. For each option, for each weir, the Atkins risk assessment has been reviewed and updated to
reflect the findings of the structural examination, silt surveys, FRAs and scour assessments detailed in this
report. No review has been undertaken of the ecological risk. The geomorphological risk and flood risk
have been reviewed only for those weirs where FRA and scour assessment have been undertaken. No
update has been made to the benefits assessment.
Key Findings
The key findings of the structural examinations and silt investigations are summarised below:
� Silt deposition behind the weirs was generally found to be approximately 1m in depth at all of the weir
locations;
� Contaminants were identified in concentrations that exceed guideline levels at all of the weir locations;
� From visual inspection of those sections of the weir that were clearly visible from the banks and weren’t
obscured by water or vegetation the weirs generally appear to be in fair to good condition and no
significant defects were visible;
� The structural coring of the weir structures enabled the approximate composition to be established. It
was noted that several of the weirs contain localised voided sections which any future design and
construction should take cognisance of;
Executive Summary
ii
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River Almond Structural Examination and Silt Surveys Summary Report
� Howden Bridge weir was generally noted to be of shallow construction. There is a risk of fragmentation
of the structure if any works are undertaken on shallow founded sections of the weir or on areas
containing any large voided sections;
� Flood risk is reduced by the removal of the Dowies, Peggies and Howden weirs. Weir removal has a
positive impact of modelled flood levels at all three sites but only a marginal impact on flood extents.
The flood risk modelling that was undertaken is considered to be adequate and no further flood work is
likely to be required;
� Howden Bridge currently has a ‘High’ scour risk rating. The significant drop of bed level that would
result from removal of the weir and the weir’s close proximity to the structure is likely to expose the
bridge support foundations. Given the existing high risk rating of the bridge, and its vulnerability to the
downstream weir level, it is important that the weir be retained to conserve the structural stability of the
bridge; and
� Cramond Bridge currently has a ‘Low’ scour risk rating. Weir removal will cause lowering of the bed
which is likely to affect the structural integrity of the bridge apron and could lead to its failure and
exposure of the bridge foundations. The scour risk rating following removal of Dowies weir is ‘High’.
Recommendations
The surveys and investigations have been undertaken to establish the current baseline and to assess the
key risks associated with barrier easement options. The work to date has been focussed on identifying a
preferred option for each of the seven individual weirs. It recommended that the data gathered as part of
this study, and reported herein, is now used to inform a catchment level River Almond feasibility study
which takes a holistic approach to improving fish passage in the reach of river from Seafield Weir to
Peggies Weir. It is expected that such a study would identify where easement would have the greatest
impact on WFD status, where constraints at one weir site would impact on benefits gained from
undertaking easement measures at another weir site and the cumulative impact/risk of combinations of
options. This will allow the optimum holistic solution, in terms of benefit and value for money to be
identified and the sequence of improvement works to be prioritised.
In addition the following recommendations are made based on the specific findings of this study:
� It is recommended that contamination assessment, dispersal and deposition analysis be undertaken to
assess the impacts of release of sediments following weir removal;
� It is recommended that the level and condition of the Howden Bridge weir should be monitored as part
of the Howden Bridge inspection regime;
� As the scour potential at the Cramond Brig is sensitive to the condition of its apron, it is recommended
that the condition of the apron be monitored as part of the ongoing maintenance programme at the
bridge;
� If removal of Dowies Weir is taken forward as a preferred option, it is recommended that during the
design stage a more detailed geomorphological assessment be undertaken to confirm the bed profile at
the Cramond Brig for post weir removal conditions; and
� Potential mitigation measures for bed strengthening downstream of Cramond Brig should be
investigated.
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1.1 Background
The River Almond is classified, by SEPA (under Water Framework Directive (WFD) classification
guidelines) as being ‘poor’ status as a result of pollution and river morphology. This ‘poor’ status is
partially as a result of point source pollution, mainly caused by sewage disposal which is increasing the
River Almond’s phosphorus levels and introducing unknown organics into the river. However, barriers to
fish passage on the River Almond are also contributing to the WFD ‘poor’ status.
There is a requirement on the River Almond landowners to improve the status of the water body by 2020.
Many of the barriers on the River Almond are no longer required for abstraction and could potentially be
removed or modified to improve fish passage and extend the distribution of migratory fish throughout the
catchment.
The River and Fisheries Trusts of Scotland (RAFTS), in partnership with the Scottish Environmental
Protection Agency (SEPA), are financing a project to assess the feasibility of improving fish passage at
seven weirs on the River Almond. These weirs are Peggies Mill, Dowies Mill, Mid Calder Weir, Rugby
Club Weir, Howden Bridge Weir, Kirkton Weir and Seafield Weir.
In 2010, SEPA commissioned Atkins to undertake a study to assess ten barriers located on the River
Almond and identify potential options for removal or modification to improve fish passage. This study
evaluated the feasibility of potential options for each weir including full removal, partial removal and fish-
passes. The findings of the study were presented in the Atkins’ report ‘Assessment of Restoration Options,
River Almond’ (30 March 2011). The study concluded that weir removal/easement may be feasible subject
to further comprehensive assessment of the risks.
Mott MacDonald Limited was commissioned by RAFTS in November 2013 to undertake investigations to
assess the following key risks:
� Sediment mobilisation, including potentially contaminated sediment.
� Unknown construction of weirs.
� Impact of weir removal on upstream bridges.
� Impact on flood risk at 3 vulnerable sites.
1.2 Purpose and Structure of Report
This report summarises the findings of the site surveys and presents the conclusions of the flood risk
assessments undertaken for the Peggies, Dowies and Howden Bridge sites and the scour assessments
undertaken for the bridges upstream of Dowies Weir and Howden Bridge Weir.
This report is supported by site specific Structural Examination and Silt Survey reports which provide
further detail of the surveys and investigations undertaken at each site. This summary is also supported by
the flood risk assessment reports for Cramond Weirs (Dowies and Peggies) and Howden Bridge Weir.
In 2011, Atkins identified restoration options for each site and assessed the risk-benefit of each option.
The Atkins risk assessment has been reviewed in light of the findings of this study.
1 Introduction
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The structure of this report is split into the following sections:
Table 1.1: Report structure
Section Topic
Section 1 Introduction
Section 2 Scope and Methodology
Sections 3 to 10 Site specific survey findings
Section 11 Benefit Risk Ranking register
Section 12 Findings and Recommendations
Section 13 References
1.3 Site Location and Description
Five of the weir locations are clustered around Livingston, the largest urban conurbation within the council
district of West Lothian. Two of the weirs are located downstream near Cramond village, a suburban area
on the western margin of Edinburgh. The locations are summarised in Figure 1.1 below. For each weir,
the site description is summarised in Table 1.2: Site details summary. The Geo-Environmental Desk
Studies undertaken by MML in 2014 (Ref. 1) provide further information on each site with regards to
geology, hydrology, historical land use and mining.
Figure 1.1: Location Map (not to scale) Showing Weir Positions
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Table 1.2: Site details summary
Aspect Details
Site Name Peggies Mill Weir – River Almond
National Grid Reference (NGR) 31800, 676420
Location Peggies Mill Weir is located on the River Almond in the vicinity of Cramond, west of Edinburgh, approximately 800m north east of the A90 trunk road and is approximately 500m south west of the mouth of the River Almond where it enters into the Firth of Forth Estuary.
Site Description • The Peggies Mill Weir site spans across the River Almond.
• At this location the river flows in a general south west to north east direction.
• The weir is approximately 2.5m in height and approximately 30m wide.
• A fish pass is present along the northern edge of the weir.
• A masonry wall is present on the southern bank of the river, and extends approximately 15m upstream of the weir.
• The northern bank is an approximately 20m high sub-vertical rock face.
Site Name Dowies Mill Weir – River Almond
NGR 317910, 675640
Location Dowies Mill Weir is located upstream of Peggies Mill Weir on the River Almond, in the vicinity of Cramond, west of Edinburgh. The site lies directly west of Barnton, and approximately 100m north east of the A90 truck road and 1.7km south west of the mouth of the River Almond where it enters into the Firth of Forth Estuary.
Site Description • The Dowies Mill Weir site spans across a bend on the River Almond.
• At this location the river flows in a general south to north direction after which it sweeps round to a general north east direction
• The weir is of typically a curved construction spanning approximately 70m in a skewed south west to north east orientation across the river.
• The weir is approximately 1.5m in height with shallow downstream slope.
• Remains of a structure are present to the eastern downstream edge of the weir, and a fish pass is also present to the east of the weir.
• There are several small vegetated islands downstream of the weir.
• The banks of the river are gently to steeply sloping.
• Cramond Brig Bridge is present approximately 150m upstream of the weir.
Site Name Mid Calder Weir
NGR 307780, 668040
Location Mid Calder Weir is located on the River Almond immediately north of Mid Calder village, south east of Livingston, and lies approximately 160m north east of the Pumpherston Road (B8046) masonry bridge crossing over the river channel.
Site Description • The Mid Calder Weir site spans the River Almond.
• At the location of the weir, the river flows in a general south to north direction between two meander features.
• The weir is approximately 2.5m in height and approximately 65m wide in a south west to north east orientation.
• A two-tiered fish pass is present in the centre of the weir.
• The River Almond diverges into three flows around and through a large vegetated island immediately downstream of the weir, converging to form a single river flow approximately 125m further downstream.
• A concrete pass exists over the remains of a former lade on the eastern river bank, adjacent to the weir.
Site Name Rugby Club Weir – River Almond
NGR 307210, 667720
Location Rugby Club Weir is located in the River Almond, immediately north west of Mid Calder and approximately 12 miles south west of Edinburgh city centre.
Site Description • The site is located at the bottom of a shallow valley at approximately 90m AOD.
• Rugby Club Weir currently occupies the site, which is of masonry construction approximately 3m in height and 20m wide. A two-tiered fish pass is located at the centre of the weir.
• The river diverges into two flows upstream of the weir, around a vegetated island. The weir is located in the eastern divergence and is approximately 20m wide.
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• A footbridge is located approximately 35m downstream of the weir.
• A steel sheet pile wall provides support to the eastern bank along the full length of the river between the weir and the footbridge.
• The western divergence of the river is 1-2m wide with shallow, slow flowing water.
• Giant Hogweed is known to be present downstream on the vegetated island
Site Name Howden Bridge – River Almond
NGR 306070, 667210
Location Howden Bridge Weir is located on the River Almond in Howden, in the centre of Livingston. The site lies adjacent to the historical masonry arch Howden Bridge structure crossing over the river channel.
Site Description • The Howden Bridge Weir site spans across the River Almond, approximately 15m downstream of the masonry arched Howden Bridge at its southern end.
• At the site location, the River Almond flows in a general south west to north east direction.
• The weir is approximately 1m in height and 35m in length.
• The weir forms a curved structure spanning from the south river bank to the northern bridge abutment rather than the north riverbank. The weir slopes from its crest to its base at approximately 30 degrees on its downstream side.
• The river diverges into three flows around two vegetated islands approximately 10m downstream of the base of the weir, and converges to form a single flow again after 40m.
• A surface water drain discharges into the river around 10m downstream.
• The southern bank of the river is generally wooded and moderately to steeply sloping. The northern bank is generally grassy and gently sloping to the west to the bridge and wooded and steeply sloping to the east.
• The Almond Valley Bridge is a 300m length bridge at 20m high carrying the A899 road through Livingstone and a footbridge cross the river approximately 80m and 140m downstream of the weir. There is a low weir located under this bridge but it was not part of this study.
Site Name Kirkton Weir – River Almond
NGR 302810, 666780
Location Kirkton Weir is located on the River Almond in Kirkton, to the south west of Livingston. The site lies approximately 200m south of the A705 road and 120m east of the B7015 road (also called Simpson Parkway Road), which crosses the River Almond west (upstream) of the weir.
Site Description • The Kirkton Weir site spans across the River Almond.
• The River Almond meanders in a general west to east direction at this location.
• The weir is approximately 2m in height and spans 28m in length.
• A riverside footpath leading from Simpsons Parkway Road in the west extends along the northern bank to the Almond Valley Heritage Centre and beyond. The footpath crosses over a functioning mill lade, and associated sluice gate, that is present upstream of the weir.
• The northern river bank is gently sloping and reeded/vegetated until the footpath and grassy beyond.
• The southern bank is heavily vegetated and steeply sloping/sub-vertical and backs onto an industrial estate present approximately 50m south of the site.
Site Name Seafield Weir – River Almond
NGR 300460, 665160
Location Seafield Weir is located on the River Almond, south of Seafield village, to the west of Livingston. The site lies approximately 750m south east of the A705 road and 800m north of the B7015 road. The Foulshiels Burn tributary enters the River Almond approximately 55m downstream of the weir.
Site Description • The Seafield Weir site spans across the River Almond.
• At this location, the river flows in a general west to east direction.
• The weir is anticipated to be of masonry construction and approximately 1m in height, spanning approximately 7m in length.
• An apron is visible to the base of the weir, extending approximately 4m downstream.
• On the north edge of the weir there is a disused metal sluice gate and penstock structure next to the weir.
• A brick wall flanks the weir on both banks, extending approximately 10m downstream of the weir and 5m upstream.
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2.1 Scope of Works
The scope of works undertaken comprised the following surveys and investigations:
� Topographic and utilities surveys;
� Geotechnical Investigation (GI) to establish the depth of the original river bed or bedrock;
� Silt investigation to determine quantity and make-up of material and contamination testing;
� Structural survey of the barriers comprising coring to determine construction and make-up and identify
any issues with removal or modification;
� Investigation to determine the depths of bridge foundations;
� Investigation of effect of removal on upstream bridges; and
� Flood risk assessment at three potentially vulnerable sites.
Table 2.1 highlights the surveys and investigations that were completed for each weir site.
Table 2.1: Site Surveys and Investigations undertaken.
2 Scope and Methodology
Site To
po
gra
ph
y a
nd
U
tili
tie
s
Ge
ote
ch
nic
al
Sil
t S
urv
ey
In
ve
sti
ga
tio
n
Str
uc
tura
l In
teg
rity
S
urv
ey
of
Ba
rrie
rs
Inv
es
tig
ati
on
of
Im
pa
ct
of
We
ir
Re
mo
va
l o
n
Up
str
ea
m B
rid
ge
s
Le
ve
l 3
Flo
od
Ris
k
As
se
ssm
en
t
Peggies Mill ♦ ♦ ♦ ♦
Dowies Mill ♦ ♦ ♦ ♦ ♦
Mid Calder Mill ♦ ♦ ♦
Rugby Club Weir ♦ ♦ ♦
Howden Bridge Weir ♦ ♦ ♦ ♦ ♦
Kirkton Weir ♦ ♦ ♦
Seafield Weir ♦ ♦
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2.2 General Methodology for Ground and Silt Investigation
To determine the quantity and composition of silt materials geophysics was used in combination with silt
sampling. Geophysical surveys enabled the river bed profile to be characterised, the depth of silt that has
accumulated on the river bed to be determined and bedrock depth to be identified.
A combination of Ground Penetrating Radar (GPR), Seismic Refraction and Resistivity Tomography
profiling geophysical methods were used to characterise the subsurface conditions. Ground truthing,
comprising competitor rig boreholes and hand held window samples on the river banks, was carried out in
order to verify the geophysical profiles at the site.
Both river bank deposits and river bed sediments were tested for geotechnical classification and for
contamination.
2.2.1 Geotechnical Testing
The following laboratory tests were specified and were undertaken to accredited methods:
� Particle Size Distribution;
� Moisture content;
� Bulk density; and
� Atterberg Limit determination (including moisture content).
2.2.2 Contamination Testing
The following determinands were included in the contamination testing suite and were tested for using
accredited methods:
Sediment Suite
� Metal Suite (As, B, Ba, Be, Cd, Cr, Cu, Fe, Pb, Hg, Ni, Se, Sb, V, Zn)
� Total Sulphur
� Water Sol. Sulphate
� Total Petroleum Hydrocarbon (TPH) Speciated (CWG) from C5 – C35
� Polycyclic Aromatic Hydrocarbon (PAH) (USEPA 16) Speciated
� Cyanide (Total and Free)
� Thiocyanate
� Phenols (Speciated) (Phenols, Cresols, Xylenols)
� Polychlorinated Biphenyls (PCBs) (EC7 Suite)
� Polybrominated Diphenyl Ethers (PBDE) (Total)
� Total Organic Carbon (TOC)
� Organochlorine Pesticides (OCPs)
� Organophosphate Pesticides (OPPs)
� Dioxins and Furans
� pH
� Asbestos Screen
Pathogens
� Listeria
� E.Coli
� Salmonella
� Total Viable Counts (TVC)
� Coliforms
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River bed sediment samples were collected from the site and analysed. An initial comparison of the results
against sediment quality guidelines, where available, has been undertaken. There is a lack of appropriate
UK sediment quality standards and so for the purposes of factual reporting, and as agreed with RAFTS
and SEPA, the Canadian Sediment Quality Guidelines for the Protection of Aquatic Life have been used. It
should be noted that the Canadian Sediment Quality Guidelines contain standards for only 28 of the 75
determinands included in the testing suite for the silt samples taken.
2.3 General Methodology for Structural Surveys of Weir
Intrusive structural investigations, comprising coring of the weirs, were undertaken to establish the
construction make-up of the weir and to determine the weir founding level.
The methodology adopted was as follows:
� Intrusive structural investigations were undertaken at six of the weirs.
� A survey specification was developed for each site, that identified the access constraints, safety risks
and the structural information desired at each structure
� Two horizontal / inclined cores were taken at each weir, safe access permitting, and were used to
determine the material composition of the weir.
� Two vertical / inclined cores through the base helped to determine the depth of the foundation.
� Samples from the cores were tested to determine material strength.
2.4 Utilities Survey
We have undertaken utility mapping and underground services/obstruction surveys. These surveys
comprised the following:
� Direct Visual Surveys: Accessible inspection chamber covers were lifted (if possible) and services
were positively identified. Levels have been provided for all services found.
� Full investigation including electronic tracing: Services were investigated by visual survey
supplemented by Ground Proving Radar, electronic, or other tracing of inaccessible routes.
� Results were verified by cross checking of existing survey records, if available.
2.5 Topographic Survey
A topographic survey of the area around each of the weir sites was undertaken. The topographic surveys
included the following key features:
Table 2.1: Topographical Surveys
Weir/s Survey
Peggies Mill, Dowies Mill and Howden Bridge Weirs
• Detailed survey of the weir structures including crest levels across the weir face, upstream and downstream cross-sections, wing walls and side profile through structure;
• Detailed channel survey to be carried out 20m upstream and downstream of the weir and lade at 1m grid spacing;
• Cross sections at 5m intervals extending 50m upstream and downstream of the weirs;
• Cross section survey locations to extend to left and right banks;
• Cross sections to include upstream and downstream of any marked footbridge and survey of the footbridge structure;
• Additional cross-sections as identified along the specific river reaches;
• Bridges to be surveyed at the following locations: Cramond Brig Toll, Queensferry Road, Howden South Road, B7015 bridges; including structure opening dimensions, soffit and
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Weir/s Survey
invert levels, wing walls and abutments, piers, channel banks, bridge deck levels where safely accessible.
Mid Calder Weir • Detailed survey of the weir structures including crest levels across the weir face, upstream and downstream cross-sections, wing walls and side profile through structure
• Detailed channel survey to be carried out 20m upstream and downstream of the weir at 1m grid spacing
• Cross sections at 10m intervals extending 150m upstream and downstream of the weir.
Rugby Club Weir • Detailed survey of the weir structures including crest levels across the weir face, upstream and downstream cross-sections, wing walls and side profile through structure
• Detailed channel survey to be carried out 20m upstream and downstream of the weir at 1m grid spacing, including both channels
• Cross sections at 5m intervals extending 50m upstream and downstream of the weir.
Kirkton Weir • Detailed survey of the weir structures including crest levels across the weir face, upstream and downstream cross-sections, wing walls and side profile through structure
• Detailed channel survey to be carried out 20m upstream and downstream of the weir and lade entrance at 1m grid spacing
• Cross sections at 5m intervals extending 50m upstream and downstream of the weir and lade entrance
Seafield Weir • Detailed survey of the weir structures including crest levels across the weir face, upstream and downstream cross-sections, wing walls and side profile through structure
• Detailed channel spot height survey 20m upstream and downstream of the weir, including any bypass/connecting channels at 1m grid spacing
• Detailed floodplain spot heights at a 5m grid to 50m from the structure
• Cross sections at 5m intervals extending 50m upstream and downstream of the weir on the River Almond and upstream from the confluence on Foulshiels Burn.
Source: Mott MacDonald
2.6 Level 3 Flood Risk Assessment
A Level 3 Flood Risk Assessment (FRA) was undertaken for the Peggies, Dowies and Howden Bridge weir
sites to assess how removal of those weirs would impact flood risk. No existing hydraulic models of the
River Almond were made available to inform this study and therefore two new models of the watercourse
were constructed, one for the lower reaches of the River Almond which includes both Peggies and Dowies
weir and one for the reach of the River Almond at Livingston containing Howden Bridge Weir.
The models are hydrodynamically linked 1D-2D ISIS TUFLOW models. ISIS and TUFLOW are industry
standard modelling packages and allow a fully quantitative assessment of flood risk.
SEPA flood maps of the area were reviewed and it was confirmed that weir removal will not impact tidal,
groundwater or pluvial design flood levels in the area of the weirs. This study therefore considers only
fluvial flood risk from the River Almond due to the removal of the weirs.
A hydrological analysis of the River Almond catchment was undertaken to derive inflows to the hydraulic
model at prescribed Annual Exceedance Probability (AEP) flood events. Details of the hydrological
analysis are presented in MM Report ‘River Almond, Hydrological Analysis, August 2014’.
The model has not been calibrated due to lack of gauged data within the modelled reach. However, a
sensitivity analysis was carried out to gain a better understanding of the model uncertainties.
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The aim of the modelling is to understand how removal of the weirs impacts flood risk in the vicinity of the
River Almond. In order to do this, the hydraulic models have been adapted to represent the following
scenarios:
� Baseline – The baseline scenario is the ‘as is’ scenario where the weirs are represented in the models
in their current state.
� Dowies Removal –The Dowies weir structure was deleted from the Cramond model.
� Peggies Removal –The Peggies weir structure was deleted from the Cramond model.
� Dowies and Peggies Removal – Both weirs are removed from the Cramond hydraulic model.
� Howden Bridge Weir Removal –The weir structure was deleted from the Howden model while
maintaining bed levels and channel geometry through the adjacent bridge. This scenario aims to
represent removal of the weir crest with no impact on the adjacent bridge structure
� Howden Bridge Weir Removal ‘A’ – Removal of the weir and re-profiling of the bed levels through the
adjacent Howden Bridge and weir location.
All model scenarios are run for a range of AEP flood events including 50% AEP, 20% AEP, 10% AEP, 4%
AEP, 2% AEP, 1% AEP, 0.5% AEP and 0.5% AEP plus allowance for climate change events.
Details of the modelling methodology are presented in MM Reports ‘Level 3 FRA – Howden Bridge’ and
‘Level 3 FRA Cramond Weirs’.
2.7 Invasive Bridge Inspections and Scour Assessment
Immediately upstream of Dowies Mill Weir and Howden Bridge Weir are historic bridge structures,
Cramond Brig and Howden Bridge respectively, which are likely to be within the zone of influence of the
weir. To support the scour assessment of these bridges, intrusive surveys comprising structural coring
were undertaken to determine bridge construction and the depth to the bridge foundations. The surveys
comprised:
� Two included cores at the bridge abutments/piers to determine the depth to the foundations.
� Two horizontal cores into the bridge abutments/piers to determine their construction.
The topographical survey included a dimensional survey of the bridge structures.
2.7.1 Scour Investigations
Scour risk was assessed using the Level 2 assessment described in the Design Manual for Roads and
Bridges guidance document BD 97/12.
The scour assessment uses the topographical survey data and water depth and velocity data derived from
the hydraulic model provided as part of the Level 3 Flood Risk Assessment (FRA) study. Additional
information from the geotechnical investigations, and Edinburgh and West Lothian Council’s contributed to
the assessment and analysis of results. The scour assessment assigns a scour risk rating between 1 and
5, with the descriptions given in Table 2.2 Risk rating descriptions.
Table2.2: Risk rating descriptions
5
Represents a low risk site with no action required beyond routine inspections
3 & 4
Represents a medium risk which may require regular monitoring and further investigations if signs of scour damage are observed during regular inspections. These structures are considered at less immediate risk of scour damage than those with risk ratings 1 and 2.
1 & 2
Represents a high risk requiring a more frequent monitoring regime and implementing mitigation measures may be appropriate. Consideration should be given to inspections following flood events. Structures with a risk rating of ‘1’ to be managed as Immediate Risk Structures in accordance with BD79/13 (DMRB Volume 3, Section 4, Part 18).
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The Level 2 scour assessment quantifies the likely depth of scour for a 0.5% annual event probability
(AEP) and compares this with the foundation depth to assign the risk rating.
2.8 Environmental survey and management
From our site walkover it became apparent that ecology surveys were required as it was identified that
there were potential ecological constraints. The ecology surveys identified that otters were present and
within the zone of influence of the survey works, trees with bat potential were identified in the vicinity of the
weirs and bat potential was also identified within each of the bridges.
Invasive species were also identified at several of the weir/bridge locations. Invasive species and the
avoidance or management of these areas would have to be further considered prior to work being
undertaken to remove or alter the seven structures.
A European Protected Species Licence (EPS) was prepared to cover the work activity and to comply with
the Conservation (Natural Habitats, &c) Regulations 1994. Environmental management of the survey
works was also undertaken to make sure that the licence conditions were complied with during the survey
works.
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3.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
upstream geophysical survey, together with the ground truthing borehole information. A ground model was
produced for the river channel (Table 3.1) and for each of the river banks (Ref: Peggies Mill Weir – RAFTS
Structural Examination and Silt Survey Report).
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
1m below river bed level across the majority of the river channel. The GPR results indicate that the
sediments thin towards the north of the river channel, towards the rock face, and thicken towards the south
bank, where approximately 2m of possible layered silt is indicated to be present.
Table 3.1: Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata (from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0-2.0
Sediment samples described as dark brown slightly gravelly clayey/silty SAND with bricks/blaes fragments.
Layer 2 Made Ground
5.0
Described as clayey Topsoil, clayey gravelly SAND and very sandy gravelly CLAY in PWBH01. Traces of ash and blaes in upper 0.4m.
Alluvium Expected to be present in the river channel.
Layer 3 Glacial Till/Alluvium Not Proven
Not encountered in the ground truthing. Described as Glacial Till/very dense saturated Alluvial deposits by the Geophysical Report.
Layer 4 Weathered Bedrock (Gullane Formation) 8.0
Not encountered in the ground truthing. Described in the Geophysical report as broken/fractured rock.
Layer 5 Bedrock (Gullane Formation) Not Proven
No encountered in the ground truthing. Described as non-rippable sandstone, siltstone and mudstone in the Geophysical Report.
The boundary between Layers 3 and 4 is indicative. It may be that this layer of superficial deposits is
absent and that the original river bed is composed of Weathered Bedrock, as indicated on the BGS
Geological Maps.
3 Peggies Mill Weir
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Figure 3.1: Ground Model
3.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified:
� Benzo(a)anthracene
� Benzo(a)pyrene
� Chrysene
� Dibenzo(a,h)anthracene
� Fluoranthene
� Phenanthrene
� Pyrene
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
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3.3 Structural Condition of Weir
Weir cores were taken as described in Peggies Mill Weir – RAFTS Structural Examination and Silt Survey
Report Rev A (August 2014). A section through the weir can be seen in the following figure:
Figure 3.2:Typical Section through Weir
Source: Geckotech Ltd Core Drilling Report
The weir is mainly of sandstone construction. The foundation depth of the weir could not be determined as
the coring could not proceed through the clay encountered.
Cores were collected on site to carry out material testing, the results are summarised in Table 3.2 below.
Table 3.2: Material testing in compression (BS EN 12504 - 1:2009)
Core Core Segment No Description Bulk Density (Mg/m3) Strength (MPa)
PW-C02 Core 1 Sandstone Block 2.39 70.7
PW-C02 Core 2 Sandstone Block 2.36 -
Source: Structural Soils Ltd Factual Report (Ref. 4)
3.4 Ecology
No significant ecological constraints were identified at Peggies Weir, however several constraints were
identified that could pose a low risk to the works, including the presence of:
� Otters;
� Invasive weeds such as Himalayan Balsam; and
� Trees with the potential for bat roosting.
Proposed mitigation measures for the avoidance of ecological disturbance are included in the Ecology
Constraints Information Document.
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3.5 Topographic and Utilities Surveys
Topographic and utilities surveys were undertaken of the area around Peggies weir. Table 3.3: Utilities
Summary summarises the utilities identified within the vicinity of the weir.
Table 3.3: Utilities Summary
Services <10m 10m-50m >50m
Underground Combined sewer �
Underground Combined sewer �
Land Drain �
Underground Sewer �
3.6 Flood Risk
For the 0.5% AEP plus climate change event, the hydraulic model shows that Peggies Weir controls water
levels for a channel length of approximately 700m upstream of the weir, i.e., almost to the toe of Dowies
Weir. Significant reductions in the peak water level occur in the vicinity of Peggies Weir from the removal of
the structure, up to a maximum reduction of 3.4m just upstream of the existing weir crest.
The hydraulic model also shows a reduction in inundated area upstream of Peggies weir but this is
relatively small given the significant reduction in modelled flood levels. This is due to the topography of the
River Almond in the vicinity of the Cramond weirs, where the steep sided river valley means the flood
extent is insensitive to water level.
Downstream of Peggies Weir there is minimal impact on water levels from the weir removal due to the
backwater impact of the third weir and the downstream boundary conditions.
Model runs were also undertaken for the scenario where both Dowies and Peggies weirs have been
removed from the model, to assess if there is a combined effect on flood risk from removing both
structures.
The hydraulic model shows that the weirs are acting independently to influence water levels in the River
Almond and therefore a combination weir removal scenario is not perceived to offer any additional benefits
in any reduction in localised flood risk.
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Figure 3.3: Peggies Weir Removal – 0.5% AEP plus Climate Change Event, Flood Extent Comparison
Source: Contains Ordnance Survey data © Crown Copyright and database right 2014
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4.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
upstream geophysical survey, together with the ground truthing borehole information. The ground model
produced for the river channel is given in Table 4.1. The indicative upstream ground model from the east
bank to the west bank is illustrated in Figure 4.1.
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
1m across the majority of the river channel based on the GPR results. In addition, the GPR results
indicate that the river bed sediments are underlain by the original Glacial Till river bed, with the weir coring
identifying Glacial Till as being the founding material for the weir.
Table 4.1: Indicative Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata (from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0
Sediment samples described as dark brown very sandy very gravelly CLAY/slightly gravelly clayey very sandy SILT.
Layer 4 Glacial Till
10.0
Described as Glacial Till in the Geophysical Report. Both the GPR survey and the weir cores indicate the original river bed was in Glacial Till.
Layer 5 Bedrock (Gullane Formation) Not Proven
Described as interbedded sandstone, siltstone and mudstone in the Geophysical Report.
Figure 4.1: Illustration of Indicative Ground Model
4 Dowies Weir
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4.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified:
� Arsenic
� Copper
� Lead
� Acenaphthene
� Acenaphthylene
� Benzo(a)anthracene
� Benzo(a)pyrene
� Chrysene
� Dibenzo(a,h)anthracene
� Fluoranthene
� Fluorene
� Naphthalene
� Phenanthrene
� Pyrene
� Zinc
The following contaminants tested for in the river bank deposit samples were found to exceed the
guidelines:
� Lead
� Benzo(a)anthracene
� Benzo(a)pyrene
� Chrysene
� Dibenzo(a,h)anthracene
� Fluoranthene
� Phenanthrene
� Pyrene
� Zinc
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
4.3 Structural Condition of Weir
Weir cores were taken as described in Dowies Weir – RAFTS Structural Examination and Silt Survey
Report Rev A (August 2014). A section through the weir can be seen in the following figure:
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Figure 4.2: Typical Section through Weir at East Bank
Source: Geckotech Ltd Core Drilling Report
The above sketch shows the results from the east bank coring. The cores show that the weir is
constructed from concrete and dolerite and that the foundation depth is approximately 1.3m to 1.4m at the
eastern bank. The inclined core taken at the eastern bank was taken further downstream and further in to
the river than the vertical core.
Figure 4.3: Typical Section through Weir at West Bank
Source: Geckotech Ltd Core Drilling Report
The above sketch shows the results from the west bank coring. The core exhibits similar material
properties to that of the east bank with concrete and dolerite being noted consistently. The core indicates
an approximate foundation depth of between 1.55 and 2.0m. Cores were collected on site by SSL to carry
out material testing. The results are summarised in Table 4.2 below.
Table 4.2: Material testing in compression (BS EN 12504 - 1:2009)
Core Core segment No Description Density (Mg/m3) Strength (MPa)
DW-C01 Core 10 Concrete 2.390 27.1
DW-C01 Core 6 Concrete 2.240 -
DW-C03 Core 1 Concrete 2.330 35.0
DW-C03 Core 2 Concrete 2.280 -
Source: Structural Soils Ltd Factual Report Table 4.2 shows that the concrete used in the construction of the weir can be assumed
to be C25/30.
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4.3.1 Bridges
Coring was undertaken on Cramond Brig to determine the foundation depths and the thickness of the
bridge piers and abutments to inform the scour assessment. Figure 4.4: Upstream Elevation of Cramond
Brig shows the abutments and pier on which the cores were taken.
Figure 4.4: Upstream Elevation of Cramond Brig
Source: Greenhatch Topographical Survey
The following figures show a schematic of the cores taken on the structure.
Figure 4.5: Cramond Brig Abutment Coring – West Bank Left Abutment
Source: Geckotech Ltd Core Drilling Reports
See Figure 4.6
See Figure 4.5
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Figure 4.6: Cramond Brig Pier Coring – Eastern Pier (Pier 2)
Source: Geckotech Ltd Core Drilling Reports
Figure 4.5 shows that the abutment has a thickness of approximately 2.0m and a foundation that extends
2.0m beneath the core location and therefore is approximately 2.8m beneath the arch springing on the
western arch.
Figure 4.6 shows that the piers have a 0.7m sandstone face over a sandstone and lime concrete core.
The foundations of the pier are approximately 3.2m below arch springing level.
4.4 Ecology
No significant ecological constraints were identified at the site, however the following constraints were
identified which required appropriate mitigation during the surveys and could pose a low risk to any future:
� Otters;
� Invasive weeds such as Giant Hogweed and Japanese Knotweed; and
� Trees with the potential for bat roosting.
4.5 Topographic and Utilities Surveys
Topographic and utilities surveys were undertaken of the area around Dowies Weir. Table 4.3: Utilities
Summary summarises the utilities identified within the vicinity of the weir.
Table 4.3: Utilities Summary
Services <10m 10m-50m >50m
Underground Combined sewer �
Overhead Cable �
Underground Gas Main �
Underground Water Pipe �
Underground Electric �
Gas – MP TFR OSA �
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4.6 Flood Risk
For the 0.5% AEP plus climate change event, the hydraulic model shows that when Dowies weir is
removed the size of the flooded area at Brae Park Road is reduced compared to the baseline. This shows
that under the existing channel and structure configuration, water levels at this location are partially
controlled by the weir crest. The deletion of the weir in the model removes the backwater influence of the
structure, lowering the peak water levels upstream significantly and providing a slight reduction in the peak
levels downstream.
Upstream of Queensferry Road Bridge and Cramond Brig there is little difference in the inundated area
and there are only small reductions in modelled flood levels in the channel. This suggests that peak flood
levels in this reach are at least partially controlled by the Cramond Brig bridge structure rather than Dowies
weir. The building inside the flood extent under the baseline scenario in this area remains inundated for the
scenario with Dowies weir removed.
Downstream of Dowies Weir there is minimal impact on water levels for a reach length of approximately
50m from the weir and there is no discernable impact further downstream.
Figure 4.7: Dowies Weir Removal – 0.5% AEP plus Climate Change Event, Maximum Flood Extent Comparison
Source: Contains Ordnance Survey data © Crown Copyright and database right 2014
Model runs have been undertaken for the scenario where both Dowies and Peggies weirs have been
removed from the model, to assess if there is a combined effect on flood risk from removing both
structures. The model shows that the weirs are acting independently to influence water levels in the River
Almond and therefore a combination weir removal scenario is not perceived to offer any additional
benefits in any reduction in localised flood risk.
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4.7 Scour Assessment
The scour assessment assesses the impact of removing the weir structure on the scour potential at the
bridge structure. The Cramond Brig is a three span masonry arch bridge located approximately 150m
downstream of the A90 Queensferry Road and 175m upstream of the Dowies Mill Weir. Figure 4.8:
Upstream elevation of Cramond Brig Upstream Elevation of Cramond Brig presents the upstream
elevation of the bridge. The bridge elements and banks are referenced from left to right when looking
downstream.
Figure 4.8: Upstream elevation of Cramond Brig
Scour risk was assessed in accordance with the methodology detailed in Section 2.7.1
Table 4.4 summarises the scour risk rating for the baseline (current) scenario and for the Dowies weir
removal scenario. A key to the scour risk rating is provided below and a detailed risk rating description is
provided in Table 2.2.
Key
Scour Risk Rating
1 High
2 High
3 Medium
4 Medium
5 Low
Table 4.4: Scour risk rating
Calculated scour risk rating
Left Abutment Pier 1 Pier 2 Right Abutment
Scenario 1- Baseline 2
Reduced to 5
1
Reduced to 5
1
Reduced to 5
1
Reduced to 5
Scenario 2- Weir removed
1 1 1 1
Based on the scour assessment undertaken as part of this study, the Cramond Brig is currently considered
at low risk of scour damage due to the presence of a protective masonry apron at the bridge pier and
abutments. Due to the critical importance of the apron in maintaining a low risk of scour at the bridge
abutments and piers, it is recommended that future works within the river reaches local to the structure
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consider the effects on this apron. It is recommended that the owner of the Cramond Brig be made aware
that the condition of the apron should be monitored as part of the ongoing maintenance programme of the
bridge.
Through our desktop review, it has been concluded that removal of Dowies Weir would result in a lowering
of bed levels at Cramond Brig by 700-800mm which would expose the bridge foundations and put the
bridge at risk of failure. If Dowies Weir were removed bed reinforcement works would be required to the
reach between the apron and the weir or modifications would be required to the apron to prevent the apron
from being undermined.
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5.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
geophysical survey, together with the ground truthing borehole information. A ground model has been
produced for the river channel the results are given in Table 5.1. The indicative upstream ground model
from the north bank to the south bank is illustrated in Figure 5.1.
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
2m below river bed level across the river channel. Additionally the GPR results indicate that the sediments
are underlain by the original Glacial Till river bed, with the weir coring identifying Glacial Till as being the
founding material for the weir.
Table 5.1: Indicative Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata
(from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0 – 2.0 Sediment samples described as very sandy slightly clayey slightly silty GRAVEL and slightly
gravelly slightly silty SAND.
Layer 4 Glacial Till Unproven Both the GPR survey and the weir cores indicate the original river bed was in Glacial Till.
Described in the Geophysical Report as compacted Glacial Till.
Figure 5.1: Illustration of Indicative Ground Model
5 Mid Calder Weir
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5.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified:
� Acenaphthylene
� Benzo(a)anthracene
� Phenanthrene
� Pyrene
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
5.3 Structural Conditions
Weir cores were taken as described in Mid Calder Weir – RAFTS Structural Examination and Silt Survey
Report Rev A (August 2014). Sections through the weir can be seen in the following figures:
Figure 5.2: Mid Calder West Core
Source: Geckotech Ltd Core Drilling Report
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Figure 5.3: Mid Calder East Core
Source: Geckotech Ltd Core Drilling Report
Figure 5.2 shows that the weir consists of concrete and dolerite to a depth of 1.78m, which is the estimated
foundation depth.
Figure 5.3 indicates that the eastern side of the weir is of similar construction. The core consisted of
concrete and dolerite throughout and the weir is estimated to be founded at a depth of 2.5m. Cores were
collected on site by SSL to carry out material testing, the results are summarised in Table 5.2: Material
testing in compression (BS EN 12504 - 1:2009) below.
Table 5.2: Material testing in compression (BS EN 12504 - 1:2009)
Core Core Segment No Description Bulk Density (Mg/m3) Strength (MPa)
MW-C02 Core 1 Concrete 2.21 16.4
MW-C03 Core 12 Concrete 2.15 -
MW-C03 Core 14 Concrete - 9.8
Source: Structural Soils Ltd Factual Report (Ref. 4)
5.4 Utilities
Topographic and utilities surveys were undertaken of the area around Mid Calder weir. Table 5.3
summarises the utilities identified within the vicinity of the weir.
Table 5.3: Utilities Summary
Services <10m 10m-50m >50m
Underground water pipe �
Underground electric �
Overhead utility (Telecom) �
Overhead power cables �
Underground pumping main �
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6.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
upstream geophysical survey, together with the ground truthing borehole information. A ground model has
been produced for the river channel and is shown in Table 6.1: Indicative Ground Model – River Channel
Table 6.1 The indicative upstream ground model from the west bank to the east bank is illustrated in Figure
6.1.
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
1m below river bed level across the river channel. The GPR results indicate that the shallow river bed
sediments are generally of a gravelly composition and are underlain by clayey till material of the original
river bed. This is confirmed by the testing of the sediment samples, which indicated gravelly sediment
underlain by Glacial Till. In addition, the weir coring identified Glacial Till as being the founding material for
the weir.
Table 6.1: Indicative Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata (from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0
Sediment sample described brown slightly sandy GRAVEL of mixed lithologies
Layer 4 Glacial Till
Not Proven
Sediment sample described as grey very sandy very gravelly CLAY. Both the GPR survey and the weir cores indicate the original river bed was in Glacial Till
Figure 6.1: Illustration of Indicative Ground Model
6 Rugby Club Weir
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6.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified.
� Benzo(a)anthracene
� Benzo(a)pyrene
� Chrysene
� Dibenzo(a,h)anthracene
� Fluoranthene
� Phenanthrene
� Pyrene
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
6.3 Structural Condition of Weir
Weir cores were taken as described in Rugby Club Weir – RAFTS Structural Examination and Silt Survey
Report Rev A (August 2014). A section through the weir can be seen in the following figure:
Figure 6.2: Typical Section through Weir – North bank
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Figure 6.3: Typical Section through Weir – South bank
Source: Geckotech Ltd Core Drilling Report (Ref. 20)
Figure 6.2 and Figure 6.3 above suggests that the weir is of concrete construction and is likely to have a
founding level of between 3.0 and 3.4m below weir crest level from the south to the north of the weir.
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Cores were collected on site by SSL to carry out material testing, the results are summarised in Table 6.2
below.
Table 6.2: Material testing in compression (BS EN 12504 - 1:2009)
Core Core segment No Description Density (Mg/m3) Strength (MPa)
RW-C01 Core 7 Concrete 2.420 32.5
RW-C01 Core 6 Concrete 2.370 -
RW-C03 Core 5 Concrete 2.400 47.7
RW-C03 Core 8 Concrete 2.350 -
Source: Structural Soils Ltd Factual Report (Ref. 21)
6.4 Ecology
No significant ecological constraints were identified at the site, however several receptors were identified
that could pose a low risk to the works, including the presence of:
� Otters;
� Invasive weeds such as Giant Hogweed and Japanese Knotweed; and
� A tree with the potential for bat roosting.
Proposed mitigation measures for the avoidance of ecological disturbance are included in the Ecology
Constraints Information Document.
6.5 Utilities
Topographic and utilities surveys were undertaken of the area around Rugby Club weir. Table 6.3
summarises the utilities identified within the vicinity of the weir.
Table 6.3: Utilities Summary
Services <10m 10m-50m >50m
Land Drain �
Underground Electric �
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7.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
geophysical survey, together with the ground truthing borehole information. A ground model has been
produced for the river channel and is given in Table 7.1. The indicative upstream ground model from the
north bank to the south bank is illustrated in Figure 7.1.
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
1m below river bed level based on the GPR results, with the sediments generally comprising a mixture of
granular and cohesive sediment across the majority of the channel, with distinct silt layering present to the
north and south bank. The GPR results indicate the sediment overlies Glacial Till, with both the coring of
the weir and Howden Bridge indicating the structures are founded on Glacial Till, the original river bed
material.
Table 7.1: Indicative Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata (from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0
Sediment samples described as Dark brown sandy GRAVEL and dark brown clayey silty
very sandy GRAVEL.
Layer 4 Glacial Till 10.0
Not encountered in the ground truthing. Described as stiff/dense sediments in
Geophysical Report.
Layer 5 Bedrock (Dinatian to Westphalian Sills) Unproven
Not encountered in the ground trothing. Described as a possible bedrock intrusion in
the Geophysical Report.
Figure 7.1: Illustration of Indicative Ground Model
7 Howden Bridge Weir
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7.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified:
� Acenaphthene
� Anthracene
� Benzo(a)anthracene
� Benzo(a)pyrene
� Chrysene
� Dibenzo(a,h)anthracene
� Fluoranthene
� Fluorene
� Phenanthrene
� Pyrene
� Zinc
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
7.3 Structural Condition of Weir
Weir cores were taken as described in Howden Bridge Weir – RAFTS Structural Examination and Silt
Survey Report Rev A (August 2014). A section through the weir can be seen in the following figure:
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Figure 7.2: Typical Section through Weir at South Bank
Source: Geckotech Ltd Core Drilling Reports
Figure 7.2 shows the core taken on the south side of the weir. Based on the vertical core, the weir is likely
to have a founding level of between 0.67m and 0.8m below weir crest level at its southern end. The
second core taken at the southern bank was located further into the watercourse suggesting that the
foundation may deepen in the centre of river.
Figure 7.3 - Typical Section through Weir at North Bank (adjacent to Howden Bridge)
Source: Geckotech Ltd Core Drilling Reports
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Figure 7.3 above shows the cores which were taken on the northern side of the watercourse adjacent to
Howden Bridge. The coring again reveals a found depth of approximately 0.6m below weir crest. The
shallow depth of concrete noted in all cores confirms site observations that the weir is constructed with a
thin concrete layer or skim over rock.
The cores were collected on site by SSL for materials testing, the results are summarised in Table 7.2
below.
Table 7.2: Material testing in compression (BS EN 12504 - 1:2009)
Core Core segment No Description Density (Mg/m3) Strength (MPa)
DW-C01 Core 10 Concrete 2.390 27.1
DW-C01 Core 6 Concrete 2.240 -
DW-C03 Core 1 Concrete 2.330 35.0
DW-C03 Core 2 Concrete 2.280 -
7.4 Bridges
Coring was undertaken on Howden Bridge to determine the foundation depths and the thickness of the
bridge pier and abutments. The elevation of Howden Bridge can be seen in Figure 7.4 below and shows
the piers and abutments on which the cores were taken.
Figure 7.4: Upstream Elevation of Howden Bridge
Source: Greenhatch Topographical Survey
The following figures provide schematics of the cores taken on the structure.
See Figure 7.5 See Figure 7.6
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Figure 7.5: Howden Bridge Pier Coring – Upstream Elevation
Source: Geckotech Ltd Core Drilling Reports
Figure 7.6: Howden Bridge Abutment Coring
Source: Geckotech Ltd Core Drilling Reports
Figure 7.5 above shows that the pier is likely to be sandstone faced with a rubble core. The sandstone
facing and dolerite equate to the facing being approximately 1.0m thick.
Figure 7.6 shows that the abutment has a 0.4m sandstone face with concrete behind. The depth of the
foundation is believed to be approximatelyf 1.5m below the arch springing.
7.5 Ecology
The following significant ecological constraints were identified at the site:
� Bats, with the potential for roosting bats identified in cracked masonry/pointing at Howden Bridge, and
also in trees on the banks of the river.
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In addition, several constraints were identified that could pose a low risk to the works, including the
presence of:
� Invasive weeds such as Japanese Knotweed; and
� Otters.
Proposed mitigation measures for the avoidance of ecological disturbance are included in the Ecology
Constraints Information Document.
7.6 Utilities
Topographic and utilities surveys were undertaken of the area around Howden Bridge weir. Table 7.3
summarises the utilities identified within the vicinity of the weir.
Table 7.3: Utilities Summary
Services <10m 10m-50m >50m
Underground Water �
BT Telecomms �
Underground Electric �
Concrete Drainage Channel �
7.7 Flood Risk
The FRA show that for the two scenarios modelled there is a reduction in fluvial flood levels upstream of
the weir location. The scenarios modelled were: 1.) Howden Bridge Weir removal only and 2.) Howden
Bridge Weir removal with re-profiling of the bed.
The weir impacts on water levels for approximately 350m upstream of the weir. In Scenario 1, the
reduction in peak water level upstream of the existing weir crest is approximately 0.7m compared to 1.0m
for Scenario 2. This is because, although the weir is removed, in Scenario 1 the large substrate under the
bridge remains and acts as a control to the upstream water level.
There is negligible impact on water levels downstream of the weir if the structure is removed. This is
mainly due to the fact that water levels downstream are controlled by a second weir under the Almond
Valley Bridge.
Despite the significant reductions in modelled flood levels, there is only a marginal impact on flood extent.
The topography of the River Almond channel valley along this reach, with a reasonably steep floodplain at
the upstream extent, ensures flows are generally contained.
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Figure 7.7: Howden Weir Removal and Bed Re-profiling – 0.5% AEP plus Climate Change Event, Maximum Flood
Extent Comparison
Source: Level 3 Flood Risk Assessment – Howden Bridge Weir. Contains Ordnance Survey data © Crown Copyright and database right 2014
7.8 Scour
Howden Bridge is a two span masonry arch bridge along the B7015 roadway traversing the River Almond.
It is located approximately 180m downstream of a B-Class road bridge off the Howden South Road and
110m upstream of the Almond Valley Bridge.
Figure 7.8: Upstream Elevation of Howden Bridge
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Scour risk was assessed in accordance with the methodology detailed in Section 2.7.1
The results of the scour assessment for the existing and post weir removal scenarios are presented in
Table 7.4. A key to the scour risk rating is provided below and a detailed risk rating description is provided
in Table 2.2.
Key
Scour Risk Rating
1 High
2 High
3 Medium
4 Medium
5 Low
Table 7.4: Scour Risk assessment
Calculated scour risk rating
Left Abutment Pier Right Abutment
Scenario 1- Baseline 3* 1* 1*
Scenario 2- Weir removed 1 1 1
*Note that although the application of the BD97/12 risk scoring methodology produces a risk score of ‘1’ (High) for the baseline scenario it is considered by MML that these elements are currently at low risk of scour due to the presence of the downstream weir. The BD97/12 method does not take account of the protection afforded by the weir and the rating overestimates the risk of scour for the baseline condition.
The results as presented in Table 7.4 suggest that the bridge has a ‘High’ scour risk rating in both
“baseline” and “post-weir removal” conditions. This ‘High’ rating is largely attributed to the shallow
foundations at the bridge. However, as explained in Table 7.4 above, the methodology does not take
account of the protection afforded by the weir in maintaining raised bed levels at the bridge and reducing
turbulence around its structural supports. Given that the weir currently protects the bridge foundations, the
existing risk of scour to the bridge is considered to be ‘Low’.
It is estimated that the bed could lower by 1.5-2.0m on removal of Howden Weir which is likely to expose
the foundations of the structural elements of the Howden Bridge and put the bridge at risk of failure. It is
recommended that the weir be retained to conserve the structural stability of the bridge. It is
recommended that the owner of these assets is made aware of this dependency, and the importance of
monitoring the level and condition of the downstream weir regularly as part of ongoing maintenance works
at the bridge.
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8.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
geophysical survey, together with the ground truthing borehole information. A ground model has been
produced for the river channel and is given in Table 8.1. The indicative upstream ground model from the
north bank to the south bank is illustrated in Figure 8.1.
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
1m below river bed level across the of the river channel. In addition, the weir coring indicates Glacial Till as
being the founding material under the weir, suggesting that this is the original river bed material.
Table 8.1: Indicative Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata
(from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0
Sediment sample described as dark brown very sandy clayey silty GRAVEL.
Layer 4 Glacial Till
3.5
Not encountered during ground truthing. Described in Geophysical Report as dense sediments, and anticipated to be present near the south river bank.
Layer 5 Weathered Bedrock (Dunnet Sandstone) Unproven
Not encountered during ground truthing. Described in Geophysical Report as non-rippable bedrock.
Figure 8.1: Illustration of Indicative Ground Model
8 Kirkton Weir
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8.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified:
� Arsenic
� Copper
� Lead
� Acenaphthene
� Benzo(a)anthracene
� Benzo(a)pyrene
� Fluorene
� Phenanthrene
� Pyrene
� Zinc
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
8.3 Structural Condition of Weir
Weir cores were taken as described in Peggies Weir – RAFTS Structural Examination and Silt Survey
Report Rev A (August 2014). A section through the weir can be seen in the following figure:
Figure 8.2: Typical Section through Weir – Northern Bank
Source: Geckotech Ltd Core Drilling Report
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Figure 8.3: Typical Section through Weir – Southern Bank
Source: Geckotech Ltd Core Drilling Report
The sections, taken adjacent to the south and north banks of the River Almond, show that the weir is
mainly of concrete construction. The foundation depth of the weir, based on the vertical core, is believed to
be approximately 2.0m below weir crest level.
Cores were collected on site by SSL to carry out material testing, the results are summarised in Table 8.2.
Table 8.2: Material testing in compression (BS EN 12504 - 1:2009)
Core Core Segment No Description Bulk Density (Mg/m3) Strength (MPa)
KW-C01 Core 1 Concrete 2.330 20.7
KW-C01 Core 2 Concrete 2.240 -
KW-C04 Core 4 Concrete 2.370 18.8
KW-C04 Core 2 Concrete 2.320 -
Source: Structural Soils Ltd Factual Report
8.4 Ecology
No significant ecological constraints were identified at the site, however several constraints were identified
that could pose a low risk to the works, including the presence of:
� Otters; and
� A tree with the potential for bat roosting.
Proposed mitigation measures for the avoidance of ecological disturbance are included in the Ecology
Constraints Information Document.
8.5 Utilities
Topographic and utilities surveys were undertaken of the area around Kirkton Weir. Table 8.3 summarises
the utilities identified within the vicinity of the weir.
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Table 8.3: Utilities Summary
Services <10m 10m-50m >50m
Land Drain �
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9.1 Ground Conditions and Silt Deposition
Indicative ground models have been developed of the site upstream of the weir from the results of the
geophysical survey, together with the ground truthing borehole information. A ground model has been
produced for the river channel and is given in Table 9.1. The indicative upstream ground model from the
north bank to the south bank is illustrated in Figure 9.1.
Depth to original river bed/depth of trapped sediment behind the weir is not thought to be any deeper than
1m below river bed level across the majority of the river channel.
Table 9.1: Indicative Ground Model – River Channel
Layer Strata
Anticipated depth to base of strata (from river bed level) (m) Description
Layer 1 River Bed Sediment 1.0
Encountered during ground truthing and described as very sandy slightly silty GRAVEL.
Layer 3 Alluvium 3.0
Not encountered during ground truthing, described in Geophysical Report as alluvial
deposits of silt, sand, and gravel.
Layer 4 Glacial Till 6.0
Not encountered during ground truthing, described in Geophysical Report as possible
Glacial Till with boulders.
Layer 5 Weathered Bedrock (Hopetoun Member Formation)
Unproven Not encountered during ground truthing but
described in Geophysical Report as weak sedimentary rock.
Figure 9.1: Illustration of Indicative Ground Model
9 Seafield Weir
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9.2 Contamination
The following contaminants were found to be present in concentrations that exceed the Canadian
Sediment Quality Guidelines which, in the absence of UK guidelines, were applied to provide an indication
of the significance of the contaminants identified:
� Copper
� Lead
� Acenaphthene
� Anthracene
� Benzo(a)anthracene
� Benzo(a)pyrene
� Chrysene
� Dibenzo(a)anthracene
� Fluoranthene
� Fluorene
� Naphthalene
� Phenanthrene
� Pyrene
� Zinc
A full summary of results for all weirs is presented in Appendix A including the Sediment Quality
Guidelines for each contaminant.
As guidelines have not been published for all of the contaminants tested, the above list does not constitute
a comprehensive list of all of the contaminants present within the silt in concentrations that may cause
adverse biological effects.
The results presented in this report are for information only, and do not constitute an interpretative
discussion or assessment of contamination risk. If the weir is to be removed, it is recommended that a
contamination risk assessment is undertaken on the river bed sediment behind the weir.
9.3 Ecology
No significant ecological constraints were identified at the site, for information please refer to the Ecology
Constraints Information Document.
9.4 Utilities
Topographic and utilities surveys were undertaken of the area around Seafield weir. Table 9.2 summarises
the utilities identified within the vicinity of the weir.
Table 9.2: Utilities Summary
Services <10m 10-50m >50m
Underground Sewer �
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10.1 Options
The 2010 Study by Atkins, ‘Assessment of Restoration Options’, considered five options for improving fish
passage at each of the seven weir sites, the options assessed were:
Option Description
Do nothing
No action taken to improve the hydromorphology or ecological (in terms of fish passage) quality of the River Almond.
Full removal
Complete removal of the obstruction to fish passage to open up the upstream catchment to migratory fish.
Partial removal
Removal of part of the obstruction/structure to make fish movement up and downstream possible.
Formal fish pass
Construction of a formal fish pass at the site to permit passage of migratory species; or
modification of existing fish pass to bring up to current standards and improve migration rate.
Informal pass
Informal easement measures which could include construction of a rock ramp, fitting of a timber or concrete baulks to the weir face or placing/moving boulders downstream of the weir.
Source: ‘Assessment of Restoration Options – River Almond, Atkins 30 March 2011.’
10.2 Summary of Approach to Risk Ranking
The risks have been reviewed in accordance with the Atkins’ methodology and with reference to the Risk
Description Tables provided within the Atkins’ report.
For each option, for each weir, the risk assessment has been reviewed and updated to reflect the findings
of the structural examination, silt surveys, FRAs and scour assessments detailed in this report. No review
has been undertaken of the ecological risk. The geomorphological risk and flood risk have been reviewed
only for those weirs where FRA and scour assessment have been undertaken. No update has been made
to the benefits assessment.
An average score was assigned to each benefit/ risk heading, based on the level of benefit/risk associated
with the option being evaluated. The scores range from 1 (no change) and 5 (major benefit/risk). Total
benefit/risk scores were then calculated for each option and the option risk/benefit categorised as high,
medium or low. The results of this categorisation were then applied to an overall ‘Risk-Benefit Ranking
Matrix’ to allow a comparative appraisal of each option, for each weir, to be undertaken (Table 10.1).
The revised risk categorisation (high/medium/low) was then applied to the Benefit-Risk Matrix to give an
updated overall risk-benefit rank for each option.
Table 10.1: Overall Risk-Benefit Ranking Matrix
Risk
L M H
Be
ne
fit H
M
L
10 Benefit-Risk Ranking Register
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10.3 Risk Ranking
The pre and post investigation benefit-risk ranking results for each of the seven weirs investigated are
presented in Table 10-2: Peggies Feasibility Risk-Benefit Ranking to Table 10-8: Seafield Feasibility Risk-
Benefit Ranking.
Table 10-2: Peggies Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal Medium High High High
Partial Removal Medium Medium Medium Medium
Formal Fish Pass Medium Medium Medium Medium
Informal Pass High Medium High Medium
Table 10-3: Dowies Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal High High High High
Partial Removal Medium Medium High Medium
Formal Fish Pass Low Medium Medium Medium
Informal Pass Medium Medium Medium Medium
Table 10-4 Mid Calder Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal High High High High
Partial Removal High Medium High Medium
Formal Fish Pass Medium Medium Medium Medium
Informal Pass Medium Medium Medium Medium
Table 10-5: Rugby Club Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal High High High High
Partial Removal Medium Medium High Medium
Formal Fish Pass Low Medium Medium Medium
Informal Pass Medium High Medium High
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Table 10-6: Howden Bridge Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal High High High High
Partial Removal High High High High
Formal Fish Pass Medium Medium Medium Medium
Informal Fish Pass
- timber baulks
Low Medium Low Medium
Informal Fish Pass
– rock ramp/pre-barrage
Medium High Medium High
Table 10-7: Kirkton Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal High High High High
Partial Removal High High High High
Formal Fish Pass Low Medium Medium Medium
Informal Pass Medium High Medium High
Table 10-8: Seafield Feasibility Risk-Benefit Ranking
Option
Pre Investigation Post Investigation
Risk Benefit Overall Risk Benefit Overall
Do nothing Low Low Low Low
Full Removal Low High Medium High
Partial Removal Medium Medium Medium Medium
Formal Fish Pass Low Medium Low Medium
Informal Pass Medium High Medium High
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11.1 Key Findings
The key findings of the structural examinations and silt investigations are summarised below:
� Silt deposition behind the weirs was generally found to be approximately 1m in depth at all of the weir
locations.
� Contaminants were identified in concentrations that exceed guideline levels at all of the weir locations.
� From visual inspection of those sections of the weir that were clearly visible from the banks and weren’t
obscured by water or vegetation the weirs generally appear to be in fair to good condition and no
significant defects were visible.
� The structural coring of the weir structures enabled the approximate composition to be established. It
was noted that several of the weirs contain localised voided sections which any future design and
construction should take cognisance of.
� Howden Bridge weir was generally noted to be of shallow construction. There is a risk of fragmentation
of the structure if any works are undertaken on shallow founded sections of the weir or on areas
containing any large voided sections.
� Flood risk is reduced by the removal of the Dowies, Peggies and Howden weirs. Weir removal has a
positive impact of modelled flood levels at all three sites but only a marginal impact on flood extents.
The flood risk modelling that was undertaken is considered to be adequate and no further flood work is
likely to be required.
� Howden Bridge currently has a ‘High’ scour risk rating. The significant drop of bed level that would
result from removal of the weir and the weir’s close proximity to the structure is likely to expose the
bridge support foundations. Given the existing high risk rating of the bridge, and its vulnerability to the
downstream weir level, it is important that the weir be retained to conserve the structural stability of the
bridge.
� Cramond Bridge currently has a ‘Low’ scour risk rating. Weir removal will cause lowering of the bed
which is likely to affect the structural integrity of the bridge apron and could lead to its failure and
exposure of the bridge foundations. The scour risk rating following removal of Dowies weir is ‘High’.
11.2 Recommendations and Further Work
The surveys and investigations have been undertaken to establish the current baseline and to assess the
key risks associated with barrier easement options. The work to date has been focussed on identifying a
preferred option for each of the seven individual weirs. It recommended that the data gathered as part of
this study, and reported herein, is now used to inform a catchment level River Almond feasibility study
which takes a holistic approach to improving fish passage in the reach of river from Seafield Weir to
Peggies Weir. It is expected that such a study would identify where easement would have the greatest
impact on WFD status, where constraints at one weir site would impact on benefits gained from
undertaking easement measures at another weir site and the cumulative impact/risk of combinations of
options. This will allow the optimum holistic solution, in terms of benefit and value for money to be
identified and the sequence of improvement works to be prioritised.
In addition the following recommendations are made based on the specific findings of this study:
� It is recommended that contamination assessment, dispersal and deposition analysis be undertaken to
assess the impacts of release of sediments following weir removal.
11 Findings and Recommendations
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� It is recommended that the level and condition of the Howden Bridge weir should be monitored as part
of the Howden Bridge inspection regime.
� As the scour potential at the Cramond Brig is sensitive to the condition of its apron, it is recommended
that the condition of the apron be monitored as part of the ongoing maintenance programme at the
bridge.
� If removal of Dowies Weir is taken forward as a preferred option, it is recommended that during the
design stage a more detailed geomorphological assessment be undertaken to confirm the bed profile
at the Cramond Brig for post weir removal conditions.
� Potential mitigation measures for bed strengthening downstream of Cramond Brig should be
investigated.
� If removal of Dowies Weir is taken forward, works would be required to the masonry apron or
downstream of the apron to make it able to cope with movement of the bed.
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General References
1. RAFTS River Almond Geo-Environmental Desk Study Rev A, Mott MacDonald, June 2014
2. Ecology Constraints Information Document, Mott MacDonald, February 2014
3. CIRIA C552
4. Canadian Sediment Quality Guidelines for the Protection of Aquatic Life: Introduction. Updated 2001.
5. Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment (CCME), Winnipeg.
6. Certificate of Analysis, Report no. 376731-1, Soil Analysis Laboratories Ltd, February 2014
7. Certificate of Analysis, Report no. 377919-1, Soil Analysis Laboratories Ltd, March 2014
8. Sediment Sampling and Testing, Report no. SES/GS/RAFTS#1, Soil Environment Services Ltd, March 2014
Peggies Mill
9. Peggies Mill and Dowies Mill Weirs Geophysical Survey Report, Report no. 3820 P-D, Version 2, Terradat, July 2014
10. Peggies Mill and Dowies Mill Weirs Final Factual Report. Report no. 540603a, Structural Soils Ltd, August 2014
11. Peggies Mill Weir Core Drilling Report, Geckotech Ltd, July 2014
12. Level 3 Flood Risk Assessment – Cramond Weirs, Mott MacDonald, August 2014
Dowies Mill
13. Geophysical Survey Report, Report no. 3820 P-D, Version 2, Terradat, July 2014
14. Peggies Mill and Dowies Mill Weirs Draft Factual Report. Report no. 540603a, Structural Soils Ltd, August 2014
15. Dowies Mill Weir Core Drilling Report, Geckotech Ltd, February 2014
16. Cramond Brig Bridge Coring Report, Geckotech Ltd, March 2014
17. Level 3 Flood Risk Assessment – Cramond Weirs, Mott MacDonald, August 2014
12 References
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Mid Calder
18. Mid Calder and Rugby Club Weirs Geophysical Survey Report, Report no. 3820 R-MC, Version 1, Terradat, July 2014
19. Mid Calder Weir Final Factual Report. Report no. 540603b, Structural Soils Ltd, August 2014
20. Mid Calder Weir Core Drilling Report, Geckotech Ltd, July 2014
Rugby Club
21. Mid Calder and Rugby Club Weirs Geophysical Survey Report, Report no. 3820 R-MC, Version 1, Terradat, July 2014
22. Rugby Club Weir Core Drilling Report, Geckotech Ltd, August 2014
23. Rugby Club Weir Final Factual Report. Report no. 540603c, Structural Soils Ltd, August 2014
Howden Bridge
24. Geophysical Survey Report, Report no. 3820 Version 1, Terradat, March 2014
25. Howden Weir Draft Factual Report. Report no. 540603d, Structural Soils Ltd, August 2014
26. Howden Weir Core Drilling Report, Geckotech Ltd, April 2014
27. Howden Bridge Coring Report, Geckotech Ltd, April 2014
28. Level 3 Flood Risk Assessment – Howden Bridge Weir, Mott MacDonald, August 2014
Kirkton Weir
29. Kirkton Weir Geophysical Survey Report, Report no. 3820 –K, Version 2, Terradat, July 2014
30. Kirkton Weir Core Drilling Report, Geckotech Ltd, March 2014
31. Kirkton Weir Final Factual Report. Report no. 540603e, Structural Soils Ltd, August 2014
Seafield Weir
32. Seafield Weir Geophysical Survey Report, Report no. 3820 – S, Version 2, Terradat, July 2014
33. Seafield Weir Final Factual Report. Report no. 540603f, Structural Soils Ltd, August 2014
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Appendices
Appendix A. Contamination Testing Results ________________________________________________________ 53
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The Canadian Sediment Quality Guidelines have been derived using chemical and biological data from
North American field-collected sediments. The Canadian guidelines normally consist of two assessment
values for each contaminant; these are the Threshold Effect Level (TEL) and the Probable Effect Level
(PEL). The TEL is the level below which adverse biological effects caused by exposure to a contaminant
rarely occur, and the PEL is the level above which these adverse biological effects frequently occur.
However, the required data to derive a TEL is currently limited and therefore only Interim Sediment Quality
Guidelines (ISQGs) have been published. It should be noted that the ISQG’s are recommended for
assessing the top 5cm of freshwater and marine sediment layers.
Appendix A. Contamination Testing Results
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Below LOD
Below ISQG
Exceeds ISQG
Exceeds PEL
Table A.1: Pathogen Suite Test Results
Determinand LOD Units SW-SS01 KW-SS01 HBW-
SS01/N HBW-
SS02/S RC-SS01 RC-SS02 MW-SS01 MW-SS02 DW-SS01 DW-SS02 PW-SS01 PW-SS02 DW-WS01
0.5m RW-WS03
0.5m
Escherichia coli 10 cfu/g <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
Listeria SPP 10 cfu/g Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
<10 Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
Presumptive Positive
Salmonella SPP in 25g N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D.
TVC at 22 C 20 cfu/g > 100000000 > 100000000
> 100000000
> 100000000 > 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
TVC at 37 C 20 cfu/g > 100000000 > 100000000
> 100000000
> 100000000 > 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
> 100000000
Total coliforms 10 cfu/g 360 120 600 60 140 <20 40 100 600 260 100 20 <20 20
Table A.2: Sediment Suite Test Results - Determinands included in CCME
Determinand Units ISQG PEL SW-SS01 KW-SS01 HBW-
SS01/N HBW-
SS02/S RC-SS01 RC-SS02 MW-SS01 MW-SS02 DW-SS01 DW-SS02 PW-SS01 PW-SS02 DW-WS01 RW-
WS03
Arsenic µg/kg 5900 17000 5000 20000 4000 3000 5000 2000 2000 <2000 15000 31000 2000 2000 5000 4000
Cadmium µg/kg 600 3500 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000
Chlordane µg/kg 4.5 8.87 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
Chromium µg/kg 37300 90000 15000 14000 12000 15000 32000 34000 11000 10000 19000 14000 12000 13000 16000 16000
Copper µg/kg 35700 197000 39000 55000 13000 24000 24000 31000 11000 7000 41000 65000 20000 17000 26000 21000
DDD µg/kg 3.54 8.51 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
DDE µg/kg 1.42 6.75 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
DDT µg/kg 1.19 4.77 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
Dieldrin µg/kg 2.85 6.67 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
Endrin µg/kg 2.67 62.4 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
Heptachlor epoxide µg/kg 0.6 2.74 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
Lead µg/kg 35000 91300 63000 120000 12000 24000 15000 15000 18000 12000 35000 75000 32000 19000 38000 23000
Lindane µg/kg 0.94 1.38 <10 <50 <50 <50 <10 <10 <10 <10 <50 <10 <10 <50 <10 <10
Mercury µg/kg 170 486 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000 <1000
Acenaphthene µg/kg 6.71 88.9 40 20 <10 40 <10 <10 <10 <10 <10 20 <10 <10 <10 <10
Acenaphthylene µg/kg 5.87 128 <10 <10 <10 <10 <10 <10 <10 10 <10 10 <10 <10 <10 <10
Anthracene µg/kg 46.9 245 60 40 <10 80 <10 <10 <10 20 20 30 20 10 20 30
Benzo(a)anthracene µg/kg 31.7 385 140 50 20 230 20 10 30 40 70 80 90 50 100 110
Benzo(a)pyrene µg/kg 31.9 782 130 40 20 170 20 10 30 30 60 70 90 50 90 120
Chrysene µg/kg 57.1 862 130 50 20 230 30 10 30 30 50 80 80 50 90 110
Dibenzo(a,h)anthracene µg/kg 6.22 135 20 <10 <10 20 <10 <10 <10 <10 10 10 10 <10 10 20
Fluoranthene µg/kg 111 2355 300 90 30 680 60 20 60 80 90 160 200 120 240 270
Fluorene µg/kg 21.2 144 70 30 <10 40 <10 <10 <10 20 20 30 <10 <10 <10 <10
Naphthalene µg/kg 34.6 391 90 20 <10 <10 <10 <10 <10 20 10 50 <10 <10 10 10
Phenanthrene µg/kg 41.9 515 240 90 10 510 40 20 20 60 70 100 50 40 80 110
Pyrene µg/kg 53 875 260 90 30 520 50 20 60 70 130 150 180 110 220 250
tPCB µg/kg 34.1 277 2.7 1.1 <3.5 <3.5 <0.35 <0.35 <0.35 <0.35 <0.35 <0.35 4.8 <3.5 2 <3.5
Zinc µg/kg 123000 315000 240000 190000 83000 150000 86000 81000 98000 64000 150000 210000 110000 96000 150000 100000
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Table A.3: Dioxins and Furans - Determinands included in CCME
Sample Location Units ISQG PEL
WHO 2005 Toxic Equivalents
Lower Bound Upper Bound
SW-SS01 ng/kg 0.85 21.5 0.55 1.2
KW-SS01 ng/kg 0.85 21.5 0.04 0.88
HBW-SS01/N ng/kg 0.85 21.5 0.011 1
HBW-SS02/S ng/kg 0.85 21.5 0.053 0.75
RC-SS01 ng/kg 0.85 21.5 0.019 0.87
RC-SS02 ng/kg 0.85 21.5 0.039 1.2
MW-SS01 ng/kg 0.85 21.5 2.2 2.7
MW-SS02 ng/kg 0.85 21.5 0.025 0.72
DW-SS01 ng/kg 0.85 21.5 0.036 0.85
DW-SS02 ng/kg 0.85 21.5 0.043 1.2
PW-SS01 ng/kg 0.85 21.5 0.031 0.75
PW-SS02 ng/kg 0.85 21.5 0.049 0.84
DW-WS01 0.5m ng/kg 0.85 21.5 1.1 1.6
RW-WS03 0.5m ng/kg 0.85 21.5 0.088 0.89
Table A.4: Sediment Suite Test Results - Determinands not included in CCME
Determinand Units LOD SW-SS01 KW-SS01 HBW-
SS01/N HBW-
SS02/S RC-SS01 RC-SS02 MW-SS01 MW-SS02 DW-SS01 DW-SS02 PW-SS01 PW-SS02 DW-WS01 RW-WS03
Abestos - - N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D.
Cyanide (Total) mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
Cyanide (Free) mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
Poly Brominated Diphenyl Ethers (Total 1-10)
mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
Total Organic Carbon % 0.1 15 9.7 2.9 2.8 1.1 1.2 1.2 0.6 3.1 14 0.4 1.1 2.7 2
Sulphate (2:1) mg/l 10 450 820 31 580 31 38 110 140 330 340 75 290 93 24
Sulphur (Total) % 0.01 0.99 1.3 0.04 0.28 0.07 0.09 0.08 0.03 0.2 0.33 0.04 0.09 0.08 0.03
Thiocyanate mg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
pH - - 7.6 7 7.5 6.8 8.6 8.6 7.2 7.3 6.4 7.2 7.2 6.4 6.8 7.2
Hexachlorobenzene mg/kg 1.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Heptachlor mg/kg 2.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Aldrin mg/kg 3.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Endosulphan mg/kg 4.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Dichlorvos mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Mevinphos mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Dimethoate mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Diazinon mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Pirimiphos methyl mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Malathion mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Fenitrothion mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Parathion mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
Azinphos methyl mg/kg 0.01 <0.01 <0.05 <0.05 <0.05 <0.01 <0.01 <0.01 <0.01 <0.05 <0.01 <0.01 <0.05 <0.01 <0.01
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Determinand Units LOD SW-SS01 KW-SS01 HBW-
SS01/N HBW-
SS02/S RC-SS01 RC-SS02 MW-SS01 MW-SS02 DW-SS01 DW-SS02 PW-SS01 PW-SS02 DW-WS01 RW-WS03
Polychlorinated biphenyl BZ#101 µg/kg 0.05 0.24 0.11 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.21 <0.05 0.34 <0.05
Polychlorinated biphenyl BZ#118 µg/kg 0.05 0.17 0.07 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.19 <0.05 0.2 <0.05
Polychlorinated biphenyl BZ#138 µg/kg 0.05 0.13 0.07 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.57 <0.05 0.37 <0.05
Polychlorinated biphenyl BZ#153 µg/kg 0.05 0.1 0.08 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.8 <0.05 0.43 <0.05
Polychlorinated biphenyl BZ#180 µg/kg 0.05 0.08 0.07 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 2.9 <0.05 0.38 <0.05
Polychlorinated biphenyl BZ#28 µg/kg 0.05 1.4 0.5 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.06 <0.05 0.1 <0.05
Polychlorinated biphenyl BZ#52 µg/kg 0.05 0.56 0.2 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.07 <0.05 0.2 <0.05
Cresols mg/kg 0.01 0.11 0.03 <0.01 0.02 <0.01 <0.01 <0.01 0.26 0.12 0.08 0.04 0.16 <0.01 <0.01
Phenol mg/kg 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Xylenols mg/kg 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01
Antimony mg/kg 4 <4 <4 <4 <4 <4 <4 <4 <4 <4 <4 <4 <4 <4 <4
Barium mg/kg 2 150 120 260 110 140 140 91 90 170 200 60 77 130 120
Beryllium mg/kg 1 2 <1 <1 <1 <1 <1 <1 <1 1 <1 <1 <1 <1 <1
Boron (water-soluble) mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
Iron mg/kg 130 47000 41000 29000 29000 47000 47000 22000 19000 43000 25000 32000 23000 28000 33000
Nickel mg/kg 1 59 34 22 22 46 49 17 13 37 37 16 17 30 28
Selenium mg/kg 3 6 4 4 <3 <3 <3 <3 <3 <3 <3 <3 <3 3 <3
Vanadium mg/kg 1 31 25 24 28 48 51 22 17 33 28 63 32 30 35
TPH Aliphatic C5 - C6 µg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
TPH Aliphatic C6 - C8 µg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
TPH Aliphatic C8 - C10 µg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
TPH Aliphatic C10 - C12 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aliphatic C12 - C16 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aliphatic C16 - C21 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aliphatic C21 - C35 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aromatic C6 - C7 µg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
TPH Aromatic C7 - C8 µg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 36 <10 <10
TPH Aromatic C8 - C10 µg/kg 10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10
TPH Aromatic C10 - C12 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aromatic C12 - C16 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aromatic C16 - C21 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
TPH Aromatic C21 - C35 mg/kg 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1
Benzo(b)fluoranthene mg/kg 0.01 0.18 0.05 0.03 0.24 0.03 0.01 0.04 0.04 0.06 0.09 0.11 0.06 0.11 0.14
Benzo(k)fluoranthene mg/kg 0.01 0.08 0.02 0.01 0.09 0.02 <0.01 0.01 0.02 0.02 0.04 0.05 0.03 0.05 0.06
Indeno(123-cd)pyrene mg/kg 0.01 0.07 0.02 0.02 0.09 0.02 <0.01 0.02 0.02 0.03 0.04 0.05 0.03 0.05 0.07
Benzo(ghi)perylene mg/kg 0.01 0.1 0.03 0.02 0.11 0.02 0.01 0.03 0.02 0.05 0.05 0.07 0.04 0.07 0.09
PAH (total) mg/kg 0.01 1.9 0.64 0.21 3.1 0.31 0.11 0.33 0.48 0.69 1 1 0.59 1.1 1.4
River Almond Structural Examination and Silt Surveys Summary Report
319034/BNI/SNI/001/A 22 October 2014 C:\Users\kea20006\AppData\Roaming\OpenText\OTEdit\EC_EUNAPiMS\c1572921271\River Almond Survey Report Final 22-10-14.docx (1572921266)_.docx
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