addendum report publication version

MIDLOTHIAN COUNCIL

A701, A702, A703 ROAD ALIGNMENT OPTIONS

Addendum Feasibility Report

March 2013

Wardell Armstrong Suite 2/3, Great Michael House, 14 Links Place, Edinburgh, EH6 7EZ, United Kingdom Telephone: +44 (0)131 555 3311 Facsimile: +44 (0)131 553 3284 www.wardell-armstrong.com

Wardell Armstrong is the trading name of Wardell Armstrong LLP, Registered in England No. OC307138.

Registered office: Sir Henry Doulton House, Forge Lane, Etruria, Stoke-on-Trent, ST1 5BD, United Kingdom

UK Offices: Stoke-on-Trent, Cardiff, Edinburgh, Greater Manchester, London, Newcastle upon Tyne, Sheffield, Truro, West Bromwich. International Offices: Moscow, Almaty

ENERGY AND CLIMATE CHANGE ENVIRONMENT AND SUSTAINABILITY

INFRASTRUCTURE AND UTILITIES LAND AND PROPERTY

MINING, QUARRYING AND MINERAL ESTATES WASTE RESOURCE MANAGEMENT

DATE ISSUED: 15th March 2013

JOB NUMBER: ED10977

ELECTRONIC REFERENCE: ED10977-02991

REPORT NUMBER: ED10977-002

A701, A702, A703 Road Alignment Options

Addendum Feasibility Report

March 2013

PREPARED BY:

Chris Richardson Senior Civil Engineer

Carl Hamer

Associate Director

APPROVED BY:

Neil Sutherland Regional Director

This report has been prepared by Wardell Armstrong LLP with all reasonable skill, care and diligence, within the terms of the Contract

with the Client. The report is confidential to the Client and Wardell Armstrong LLP accepts no responsibility of whatever nature to third

parties to whom this report may be made known.

No part of this document may be reproduced without the prior written approval of Wardell Armstrong LLP.

A701, A702, A703 Road Alignment Options Addendum Feasibility Report

ED10977/ED10977-002 March 2013

CONTENTS

1 INTRODUCTION .................................................................................................................. 1

2 LAND OWNERSHIP .............................................................................................................. 3

3 SITE WALKOVER SURVEY .................................................................................................... 4

4 ROAD OPTIONS ................................................................................................................... 7

5 CONSTRAINTS TO ROAD CONSTRUCION .......................................................................... 10

6 ROAD CONSTRUCTION COSTS .......................................................................................... 14

7 DEVELOPMENT AREAS ...................................................................................................... 18

8 CONCLUSIONS AND RECOMMENDATIONS ...................................................................... 20

APPENDICES

Appendix A Photographic Record (CD Rom)

Appendix B Table 1 approximate road option costs and Table 2 approximate cut and fill

volumes.

DRAWINGS

Drawing

Number

Title Scale

ED10977-001-A Constraints to Road Construction 1:5,000

ED10977-002-A Location Plan 1:5,000

ED10977-003 Option 1 - Dual carriageway to the west of Cameron Wood 1:5,000

ED10977-004 Option 1 - Single carriageway to the west of Cameron Wood 1:5,000

ED10977-005 Option 1 - Plan and Sections As Shown

ED10977-006 Option 2 - Dual carriageway to the west of the cemetery and

east of Cameron Wood

1:5,000

ED10977-007 Option 2 - Single carriageway to the west of the cemetery and

east of Cameron Wood

1:5,000


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ED10977-009 Option 3 - Dual carriageway to the east of the cemetery and

Cameron Wood

1:5,000

ED10977-010 Option 3 - Single carriageway to the east of the cemetery and

Cameron Wood

1:5,000


ED10977-012 Option 4 - Dual carriageway to the east of the cemetery and

Cameron Wood

1:5,000

ED10977-013 Option 4 - Single carriageway to the east of the cemetery and

Cameron Wood

1:5,000


ED10977-015A Single carriageway link between A703 and A702 1:2,500

ED10977-016 Photographic View Points 1:5,000

ED10977-023* Option 1 Future Development Areas 1:10,000




37415/3

Figure 1

Gas Monitoring Locations NTS

* Maps not included contain commercially sensitive information.


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1 INTRODUCTION

1.1 Midlothian Council is assessing the feasibility of new road alignment options connecting the A701, A702 and A703 to assist in the preparation of the Main Issues

Report for the Local Development Plan. The Council prepared a preliminary

assessment of road options:

A blue route running from Straiton roundabout generally parallel with the A701 to the west of the park and ride and Straiton Park residential caravan

site before turning west towards Pentland Mains.

A green route which runs further west than the blue route, cutting across the northern edge of Straiton Bing turning south west between Cameron Wood

and Old Pentland towards Pentland Mains. The blue and the green route

merge immediately south of Pentland House and turn south west to merge

with the A703.

A red route connects the A703 north of Seafield Mill to the A702 north of Boghall.

1.2 Wardell Armstrong LLP submitted a fee proposal on 7th August 2012 to review the Councils records relating to the land corridor through which the proposed new

roads would be constructed.

1.3 Wardell Armstrong was commissioned by the Council in a letter dated 21st August to undertake a phased assessment of the road alignment options as detailed in the

proposal and in addition to undertake a site walkover of the preferred road

alignment.

1.4 Our preliminary feasibility study report referenced ED10977-001 was issued on 5th October 2012. That report recommended that the blue route is not geotechnically

viable and further work including the walkover survey should be carried out

concentrating on a road corridor along the approximate route of the green and red

routes.

1.5 This addendum report provides a more detailed assessment of road alignment options taking consideration of the topographical, environmental, geological, mining

and geotechnical constraints to road construction that were identified in our

preliminary report and seen during the site walkover. Estimates have been made for


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the cut and fill requirements and approximate cost of each of the road options.

Potential high, medium and low risk/cost development areas between the proposed

road options and the A701 have been identified.


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2 LAND OWNERSHIP

2.1 Wardell Armstrong was provided by the Council with some details of the landownership through the approximate road corridor under review.

2.2 The main landowners are as follows:

Midlothian Council Land adjoining the A720 and A701 at Straiton roundabout and

the footprint of Straiton Bing.

Morston Assets Land to the west of the A701 and north of Straiton Bing subdivided

into strips alternatively controlled by Peregrine Edinburgh Ltd and Lansdowne

Holdings Ltd.

Gibsone Trust Land to the west of Straiton Bing and east of Cameron Wood

including Old Pentland cemetery.

William R McEwan Pentland Mains Farm and the former landfill.

Mrs C Newbould Pentland House, Pentland House Stables and land to the west of

Cameron Wood.

Trustees of Robert Lawrie & Sons Land to the east of the A703.

Scotlands Rural College (SRUC) Land between the A703 and the A701.

2.3 Wardell Armstrong contacted all the above landowners to seek permission to access their land for the purposes of a walkover survey. The majority of the landowners

agreed to our request.


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3 SITE WALKOVER SURVEY

3.1 A Wardell Armstrong engineer carried out a walkover survey on 20th November 2012. A photographic record is attached on CD Rom and drawing number ED10977-

016 shows the photograph view points.

3.2 Access to Straiton Bing was gained from the north of Straiton Residential Caravan Park. The north and eastern areas of the bing are relatively flat at between 140 and

145m AOD and are generally 4 to 5m above the surrounding farm land (photo 13).

The majority of this area is covered by scrub vegetation (coarse grass, bramble,

gorse, broom and a variety of trees) with occasional blocks of fused blaes (photos 1,

2 and 5). There is a steep slope/cliff from along the southern margin of this area

(photos 3, 6 and 7) which borders the Tarmac Topmix plant (photo 9). Ground levels

rise from c.150m AOD at the toe to between 160 and 166m at the crest. The

steepest sections of the slopes are formed from fused blocks of blaes/burnt shale

3.3 In the central area of the bing the ground is more undulating and there is a deep depression with a ground levels falling steeply to a base at c. 136mAOD (photos 4, 8

and 11). There is less vegetation cover of the burnt shale/blaes. It is likely that this

was formed by the extraction of blaes/burnt shale for use in construction projects

such as the A720. The base may reflect the original ground level prior to formation of

the bing.

3.4 The digital terrain model (DTM) purchased for the site does not reflect the true topography of Straiton Bing, which is shown in Figure 2 of RPSs report

Development Options for Straiton Bing dated 16th April 2009. Their drawing is

based on LIDAR Contour data Midlothian Council Survey File No. 258, 03.12.08

(Neg Nt2666/T/258).

3.5 The bing is criss-crossed by numerous tracks used by off road motorcycles and dog walkers.

3.6 To the west of Straiton roundabout the ground falls quite steeply to a low lying marshy area (photos 17 and 19). To the south of this the ground level rises 3 to 4m

up a steep embankment. This appears to be man-made and is possibly associated

with localised sand and gravel extraction accessed from a track off the A701

although none is recorded on the historical mapping in this area (photo 20). The


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earthworks are not discernable on the DTM/LIDAR data for the area. There has been

some fly tipping of broken concrete, tarmac and wire, although none of this appears

to be recent. Further west there is another marshy area in the vicinity of a former

reservoir.

3.7 To the west of the park and ride and north of the bing is relatively gently sloping arable farm land (photos 13 to 16, 18, 21, 22 and 24). There is a mine shaft recorded

on the apex of a rounded 90 degree field boundary. The soils in this area contained a

significant amount of mudstone and siltstone rock fragments suggesting this is a

fairly accurate position. Also on this field boundary there was evidence of fly-tipping

waste originating from the Straiton Bed Co. Ltd. (Photo 23).

3.8 To the north west of the bing there is a triangular shaped low lying very marshy area (photos 25, 26 and 27).

3.9 Pasture land rises gently around the western end of the bing towards Old Pentland cemetery and Pentland Road/Damhead (photos 26 and 28). The cemetery is located

on a knoll surrounded by a dry stone wall (photos 32, 34 and 47). The south side of

Pentland Road/Damhead, opposite the cemetery, is formed by a steep c. 3m high

embankment cut into the slope (photo 29). The cutting is not discernable on the

DTM for the area.

3.10 Cameron Wood runs along the axis of c. 5m high ridge that is likely to be a elongated glacial drift feature. The former quarry at the northern end is overgrown (photo 37)

but it is likely that sand and gravel was extracted. The pasture land to the east

(photos 31, 33, 35, 40, 41, 42, 43, 44 and 46) and west (photos 38 and 48) of the

wood rises initially quite steadily to the south but becomes increasingly steep.

Access to the west of the wood was restricted but to the east the margins of the

wood (particularly to the south) were formed by bramble, elder, hawthorn and

sycamore. More mature trees were found at the southern end of the wood (photo

44) and on the higher slopes.

3.11 The pasture land levels out at the southern end of Cameron Wood at c. 170m AOD (photo 45) around Pentland Mains Farm and Pentland House. The former landfill has

been restored to pasture land with rough grassland at the margins. The land

between the Pentland Burn and the landfill is being infilled (photos 49, 50 and 53)

with imported materials to form more level, drained pasture as part of Pentland

House Stables. The south western corner of the former landfill is used for storage


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and processing of timber for biomass fuel and is operated by Pentland Plants Ltd

(photos 49 and 52).

3.12 To the south of the landfill and east of the A703 is relatively flat lying arable land (photo 52). There is a slight depression shown on the DTM that corresponds with a

pond on the Ordnance Survey mapping. No surface water feature was seen at this

location and the low lying area corresponds with the crop marks identified in our

preliminary report at this location.

3.13 There is a belt of coniferous woodland on the western side of the A703 at a sharp bend in the road (photos 56 and 57) opening out onto rough grassland (photo 60).

Further west is a small arable field through which three new water mains were

recently laid with valve manholes in the north eastern corner. From here pasture

land rises to the west quite steeply from c173m AOD levelling off at c. 195m AOD

and rising again to meet the A702 at c.200m AOD (photo 61).


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4 ROAD OPTIONS

4.1 Wardell Armstrong has prepared four preliminary design options for single and dual carriageway roads from Straiton roundabout to the A703 and a single option for a

single carriageway link from the A703 across to the A702. There are three significant

constraints that have defined the road alignment options:

a) Old Pentland cemetery;

b) Cameron Wood;

c) Pentland Mains Landfill

4.2 The design of all the road options is based on the Nextmap 5m DTM although we have recently been issued with a 2m DTM for most of Straiton Bing and the area to

the north. The road layout follows the dual two lane all purpose road given in the

Design Manual for Roads and Bridges (DMRB) with a 2m central reservation with,

two 3.65m wide lanes, a 1m hardstrip and a 2.5m verge each side. The single

carriageway has the same makeup with only one width of lane. The earthworks

cut/fill ties in to the DTM at a gradient of 1:3.

4.3 Each of the presented options has been based on the parameters set out in the DMRB. The route of each option was initially reviewed for a design speed of 100kph

(62mph), however, where a sharper bend was required to achieve a particular goal

or meet a constraint a lower design speed of 85kph (53mph) was also considered.

4.4 For each design speed the DMRB Table 3 sets out the desirable radius of bends, superelevation (cross fall around a bend) and the vertical curvature of the road at

the brow or base of an incline, which is expressed as a value known as 'k'. For each

design speed there are alternative minimum radii, superelevation and k values

described as one or two steps below the desirable values. For the horizontal

curvature of the bends that we have used in preliminary design, the values are the

same for single and dual carriageway.

Option 1 - Carriageway to the west of the cemetery and Cameron Wood

4.5 The alignment is based on a design speed of 100kph (62mph) with a minimum radius of 510 (one step below desirable with 7% superelevation). Vertical curvature is one

step below desirable minimum crest (k=55). See drawing numbers ED10977-003,

ED10977-004 and ED10977-005.


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Option 2 - Carriageway to the west of the cemetery and east of Cameron Wood

4.6 The alignment is based on a design speed of 85kph (53mph) with a minimum radius of 255 (two steps below desirable with 7% superelevation). Vertical curvature is one


ED10977-007 and ED10977-008.

Option 3 - Carriageway to the east of the cemetery and Cameron Wood

4.7 The alignment is based on a design speed of 85kph (53mph) with a minimum radius of 255 (two steps below desirable with 7% superelevation). Vertical curvature is one


ED10977-010 and ED10977-011.

Option 4 - Carriageway to the east of the cemetery and Cameron Wood and over

Pentland Mains Landfill

4.8 The alignment is based on a design speed of 85kph (53mph) with a minimum radius of 510 (desirable minimum with 5% superelevation). Vertical curvature is at

desirable minimum crest (k=55) for dual carriageway, adopting this value for single

carriageway would need to be discussed with the Councils transportation

department. See drawing numbers ED10977-012, ED10977-013 and ED10977-014.

A703/A702 Link

4.9 As the A702 is a single carriageway, only a single carriageway link between the A703 and A702 has been considered. The alignment is based on a design speed of 100kph

(62mph). Vertical curvature is one step below desirable minimum crest (k=55). See

drawing number ED10977-015 Revision A.

4.10 Four junctions/road crossings are required:

A new spur of Straiton roundabout;

A bridge for Pentland Road/Damhead to pass over the new road;

A new roundabout on the A703 at the location of the bad bend north of Seafield Mill; and

A T junction or roundabout at the A701 north of Boghall.


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4.11 Depending on the preferred alignment there may be additional bridges required e.g. access to Pentland House.


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5 CONSTRAINTS TO ROAD CONSTRUCTION

5.1 In addition to the constraints to road construction detailed in our preliminary feasibility study the following constraints have also been identified.

5.2 Topography

5.2.1 As detailed in paragraph 3.6, to the west of Straiton roundabout there are earthworks, possibly associated with unrecorded sand and gravel extraction. The

route of option 4 cuts though the earthworks.

5.2.2 As detailed in paragraph 3.9, Pentland Road/Damhead to the east of the cemetery is cut into the land on its south side by c.3m. The routes of options 3 and 4 pass

through this area and would create a c. 4m to 5m deep cutting.

5.3 Superficial deposits

Made Ground

5.3.1 As detailed in paragraph 5.2.1 the earthworks to the west of Straiton Bing appear to be reworked natural soils but there are some fly tipped materials.

5.3.2 As detailed in paragraph 3.6, the land between the Pentland Burn and Pentland Mains Landfill is being infilled with imported materials to form more level, drained

pasture. Options 1, 2 and 3 pass over part of this area.

5.3.3 We have been provided with a various revisions of drawing Figure 1 showing gas monitoring locations on Pentland Mains Landfill prepared by Fairhurst Consulting

Structural and Civil Engineers for Lothian Recycling 1996 Ltd dated 1st September

1999, 23rd October 2000 and 31st July 2001. The drawing is based on an earlier

drawing prepared by SAC for the same client referenced 2099-6 Revision F dated 18th

January 1999, which appears to have been prepared when the extension site was

proposed. The drawings identify:

the old tip site in the north and west;


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the existing tip site in the central and eastern areas (Phases 1 to 3 and 6);

the extension tip site in the south (phases 4 and 5, although on the latest drawing upfilled region 6? is recorded between the old tip site and phase 5).

Gas monitoring boreholes 1 to 7 incl. located on and around the whole of the landfilled area.

Gas spike holes 1 to 21 incl. located on the existing tip in the north east and 22 to 52 incl. located on the extension tip in the south.

Proposed and existing drainage and planting;

Ground level contours based on a local datum.

5.3.4 The contours on the existing tip and those of the original ground level for the proposed extension site suggest that if final formation levels were designed to tie in

with existing to the south then upfill would be in the order of 7m thick.

Natural Deposits

5.3.5 As detailed in paragraph 3.6, to the west of Straiton roundabout is an area of low lying marshy area over which all four road options pass on embankments. Option 1

extends over the additional marshy area further west. Consideration will need to be

given to either removal of the organic material and replacement with granular fill

(possibly the adjacent earthworks material) or surcharging and draining the marshy

area.

5.3.6 As detailed in paragraph 3.8, to the north west of the bing there is a triangular shaped low lying very marshy area. Option 3 passes through this marsh and options

1 and 2 pass over the northern limit. Similar remedial methods will need to be

considered in this area although the blaes would provide a more localised source of

granular material.


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5.4 Environmental

5.4.1 A badger paw print was seen (photograph 12) to the north east of the bing. As a protected species it will probably be necessary to undertake a badger survey along

the preferred route.

5.5 Land-Use

5.5.1 As detailed in paragraph 3.11, the south western corner of the Pentland Mains Landfill is used for storage and processing of timber for biomass fuel. Options 1, 2

and 3 cross the northern extent of timber storage where it is restricted by overhead

power lines. Option 4 passes through the centre of the storage area.

5.6 Discussion

5.6.1 We have already identified Cameron Wood as one of the most significant constraints within the road corridor that we have reviewed. For option 1 the design speed is

100kph (62mph) and the horizontal radius and vertical curvature have been reduced

below minimum standards to minimise encroachment into the wood. Nevertheless

there is a significant impact on the northern end of the wood cutting through the

former quarry before emerging on the western side. The dual carriageway option

has a slightly more significant impact. For options 2 and 3 the design speed has been

reduced to 85kph (53mph) and the horizontal radius and vertical curvature have

been reduced below minimum standards by two and one steps respectively to

minimise encroachment into the wood. Option 2 requires an embankment along the

western side of the road that encroaches into the wood. However the alignment of

option 3 through the bing prevents encroachment into the wood. The design speed

of option 4 is also 85kph (53mph) but the horizontal radius and vertical curvature are

at or above minimum standards. Option 4 does not encroach into the wood however

it does go on to pass through Pentland Mains Landfill.

5.6.2 Options 1, 2 and 3 encroach marginally onto Pentland Mains Landfill but option 4 involves a section of cut up to 1.7m through it. Although options 1, 2 and 3 are likely

to have less impact this section of any of the routes would need detailed site


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investigation to assess the depth and nature of the waste. SEPA would also need to

be consulted to establish the waste management issues.

5.6.3 Options 1, 2 and 3 cross the crop markings. Although this would mean detailed archaeological investigations, it is unlikely that funding would be available to assess

this feature from other sources and therefore the more direct routes might be

considered a benefit.


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6 ROAD CONSTRUCTION COSTS

6.1 Cost Basis

6.1.1 A high level cost appraisal for the each of the proposed road options has been undertaken and the following assumptions have been used.

6.1.2 Due to the limited nature of the outline design and site information this cost appraisal has been based on unit rates available in the approximate estimation

section of the SPONS Civil Engineering and Highway Works Price Book 2011. The

SPONS unit rates are approximate only and are based on information from sources

including engineers estimates, tenders and final account values for a large number

of highways contracts.

6.1.3 The unit rates only provide an indicative order of magnitude for works based on statistical frequency norms for road construction schemes of a similar type and

nature. A more detailed assessment based on more detailed and accurate

information will be required to verify the high level cost appraisal.

6.1.4 The rural all-purpose roads unit rates have been used from the SPONS manual. The values shown for the road cost in Table 1 includes for earthworks, structures,

drainage, pavements, line markings, reflective studs, footway signs, lighting

motorway communications, fencing and barrier works as well as including an

allowance for accommodation works, statutory undertakings and landscaping as

appropriate to the type and location of the carriageway. The rates do not include

purchase of the land, ground remediation or design fees.

6.1.5 The main item coverage assumed in the SPONS unit rates includes:

Overall width of the dual two lane carriageway will be 18.6m and 10m for the single carriageway;

Road construction thickness of 800mm will apply comprising of 40mm wearing course, 60mm base course, 200mm road base, 150mm sub-base and 350mm capping layer;

50% of highway length will be formed on embankment to an average height of 4m height and 50% of the highway length will be in cuttings to an average depth of 3.75m;


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30% of excavated material will be unsuitable as fill material;

No allowance for footpaths, cycle paths or kerbs and edgings is included; and

An allowance of 25% of length of carriageway will require a vehicle restraint system and 20% of the length will having lighting.

6.1.6 Additionally to the rural all-purpose road unit rate, a feature unit rate has also been included to cover for the associated construction elements such as side roads,

interchanges, underbridges, overbridges, culverts, subways, gantries and retaining

walls. This feature rate is considered to include for the roundabout junction and

bridge structure and therefore these item have not been separately accounted for in

the cost table.

6.1.7 A review of the SPONS manual unit rates was completed based on available industry data. It was found that the SPONS unit rates were within the typical range of rates

used for this type of construction and as such, based on the limited level of design

and site data available, were considered reasonable for this high level cost appraisal

stage.

6.1.8 The costing presented in Table 1 attached at Appendix B is based on the indicative route options detailed on Drawings ED10977-004 to ED10977-015A incl.

6.1.9 In summary the estimated costs for single carriageway options range from 7.18 million to 7.74 million. Estimated costs for dual carriageway options range from

12.53 million to 13.51million. The estimate cost of a single carriageway link from

the A703 to the A702 is 2.36 million.

6.1.10 Costs might be reduced by using blaes from the bing as a source of road sub-base material. To estimate the volume of blaes that might be available we have assumed

that the existing slopes to the north of the Tarmac Topmix plant are extended down

to a level of c. 145m AOD i.e. the approximate natural ground level to the east and

west and the level. The rest of the bing could be removed to the contours of the

agricultural land surrounding it. Following consultation with a contractor who has

worked extensively on the West Lothian bings it is likely to be economical to break

down and crush the fused blaes blocks and therefore we have assumed that only

10% of materials might be unsuitable. The estimated volume of blaes suitable for

use is therefore c. 304,000m3.


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6.2 Cut and Fill Estimates

6.2.1 For indicative purposes, an assessment of the cut and fill expected requirements for each of the route options has been undertaken and is presented in Table 2 attached

at Appendix B.

6.2.2 The quantities detailed are based on the outline horizontal and vertical alignment designs shown on Drawings ED10977-004 to ED10977-015A incl.

6.2.3 The cut and fill estimates have been taken directly from the outline highway design model which compares the road surface against the existing digital ground model.

No allowance for site preparation, ground remediation or improvement or road

construction thickness has been taken into account in completing the assessment.

6.2.4 In summary single carriageway options 1, 2 and 4 generate an estimated excess of between c.25,000m3 and 50,000m3 sub-soil and topsoil material. Dual carriageway

options 1, 2 and 4 generate an estimated excess of between c.37,000m3 and

c70,000m3 sub-soil and topsoil material. Option 3 is constructed on significantly

more embankment above existing ground level and requires an additional c.15,500

m3 to c.16,000m3 of granular fill. The single carriageway A703 to A702 link also

requires an additional c.4,000m3 of granular fill.

6.2.5 The quantities of excess material will be increased if blaes is used to replace unsuitable materials.

6.2.6 We have previously suggested that excess sub-soil and topsoil materials might be used to form landscaped roadside bunds to reduce the visual impact of the road or

to landscape areas of land that are unlikely to be developed in the foreseeable

future e.g. Clippens Landfill site for use as public amenity space.

6.2.7 As a guide, using the maximum estimated excess of soils would result in an increase in height of c.0.65m if spread over the whole of Clippens landfill. However, the

thickness of topsoil placed would be proportional to the landscape planting; thicker

for areas of tree planting and thinner for shrubs and grasses. It is possible that high

density planting of thorny trees/bushes such as hawthorn, blackthorn and dog rose

could be used to deter the public from entering areas where there is a risk of

subsidence. Although the topsoil and subsoil materials are likely to be


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uncontaminated consideration would need to be given to the effects of landfill gas

on any new planting.


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7 DEVELOPMENT AREAS

7.1 For each of the road options we have estimated developable land areas between the A701 and the new road option, which would act as the defensible boundary to

development within the new Local Development Plan. For the purposes of this

report developable land is agricultural or brownfield land between the boundaries of

existing properties/buildings. The development areas have been sub-divided into

areas with a likely low, medium or high risk/cost associated with addressing the

constraints that have been identified for road construction, which apply as well to

development in general.

Low cost/risk Development on greenfield land generally with low gradient slopes and no shallow mining issues.

Medium cost/risk Development on Greenfield land with significant areas of steep slope gradients and/or poor ground conditions and/or potential

shallow mining issues.

High cost/risk Development on brownfield land (former Pentland Oil works and Pentland Mains Landfill) where there is potential for soil or groundwater

pollution, landfill gas and/or potential shallow mining and/or poor ground

conditions.

7.2 Although we are aware that Taylor Wimpey have recently commenced their Phase 1 development at Cameron Gardens, Bilston we have included this area as

developable. We have not included the Clippens Landfill site as in our opinion the

geotechnical constraints preclude development.

Option 1

7.3 47.1 hectares of low cost/risk, 70.1 hectares of medium cost/risk and 17.5 hectares of high cost/risk. These areas are shown on drawing number ED10977-023.

Option 2



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Option 3


Option 4


7.7 The cost/risk zoning is likely to change if ground investigations identify additional development constraints or rule out a potential constraint. The area of each zone

may alter depending on the road width used (single or dual carriageway), the design

standards agreed with the Councils transportation department and detailed design

of junctions.


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8 CONCLUSIONS AND RECOMMENDATIONS

8.1 None of the road alignment options that have been assessed can avoid impact to all three of the main constraints without both a reduction in the suggested 100kph

(62mph) design speed of the road and also the minimum vertical and/or horizontal

curvature design standards.

8.2 Option 4 is the closest to optimum road design as it avoids direct impact on the cemetery and Cameron Wood with only a reduction in design speed to 85kph

(53mph), however without a reduction in the design standards it cannot avoid

cutting through Pentland Mains Landfill. This option also results in the lowest total

potential low, medium and high cost/risk development areas.

8.3 Option 1 to the west of Cameron Wood would have the largest visual impact to the Damhead community.

8.4 It is possible that direct impact on Cameron Wood could be avoided for other options if embankment slopes can be steepened from the 1:3 design gradients. It is

possible that ground investigation might establish that the soil geotechnical

parameters will enable steeper slopes to be constructed or retaining structures

might be considered.

8.4.1 The estimated costs for single carriageway options range from 7.18 million to 7.74 million. Estimated costs for dual carriageway options range from 12.53 million to

13.51million. The estimate cost of a single carriageway link from the A703 to the

A702 is 2.36 million. The difference in estimated costs for the various options is less

than 10% and considering the number of variables at this stage it is not considered

significant.

8.5 Three of the road options would result in a net excess of subsoil and topsoil material up to 70,000m3. This material could be used positively to landscape areas of low

development potential such as Clippens Landfill and either side of the proposed

road to soften the visual impact. Although Option 3 will generate an excess of topsoil

there is an overall net deficit. However it is unlikely that this will be a significant issue

as the bing could provide up to c. 304,000m3 of blaes for use as road sub-base

material.


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8.6 The low and medium cost/risk development areas reduce in size gradually from option 1 to option 2 and option 3 ranging from 47 to 41 hectares and 70 to 62

hectares respectively. There is less variation in the high cost/risk development areas,

which ranges between 17 and 18 hectares.

8.7 Recommendations for further works to assist in finalising a preferred road option:

Consultation with Midlothian Council roads department regarding the preferred route and the requirement to reduce road speed and minimum standards to

create sufficient developable area to assist funding of the road, minimise the

impact on features such as Old Pentland cemetery and Cameron Wood and

avoid construction constraints to minimise overall cost.

Consultation with SEPA and the landowner regarding the proposals for surrender of waste management licence(s) for Pentland Mains Landfill,

associated restoration and the practicalities of road construction through the

landfill.

Further consultation with the county archaeologist/heritage officer regarding the pros and cons of the route crossing crop marks and proximity of the route to

Old Pentland cemetery.

Liaison with Damhead Community Council to assess their views on the road options being considered.

Undertake an arbouricultural survey of Cameron Wood to enable a better assessment of the impact of an embankment encroaching into the wood.

Undertake a topographical survey or purchase more detailed DTM data for the whole of the preferred road corridor.

Undertake title deed searches for landownership that is not currently known within the preferred road corridor.


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APPENDIX A Photographic Record (see separate document)


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APPENDIX B

Table 1 Cost Estimates for Road Options

Table 2 Cut and Fill Estimates

Carriageway Type Length (m) Cost Features Cost Sub-Total

Dual Carriageway 2913 7,661,190 3,670,380 11,331,570 13,031,305.50

Single Carriageway 2913 4,282,110 2,213,880 6,495,990 7,470,388.50







A703/A702 Link Single Carriageway 920 1,352,400 699,200 2,051,600 2,359,340.00

Item SPONS Description Cost

Single Carriageway 10m 1,470

Single Carriageway 10m 760

*cost estimations taken from SPONS manual 2011 as detailed in section 6 of the report.

Total Cost (inc.

Prelims, OH&P etc)

Option 2

Route Option

Table 1 - Cost Estimates For Road Options

Features

2,630

Dual two lane Carriageway

7.3m (D2AP_U)1,260

Rural All-purpose

Roads

Option 4

Unit Rate Table

Dual two lane Carriageway

7.3m (D2AP_U)

Option 1

Option 3

Cut m3

Fill m3

Net m3

80085 25038 55047

58507 17080 41427

97245 26844 70401

69103 19435 49668

40399 56333 -15934

28108 43622 -15514

71853 34800 37053

50587 25592 24995

9908 13043 -3135A702 - A703 Single Carriageway

Table 2 - Cut and Fill Estimates

Road Options

Option 1

Option 2

Option 3

Option 4

Dual Carriageway

Single Carriageway

Dual Carriageway

Single Carriageway

Dual Carriageway

Single Carriageway

Dual Carriageway

Single Carriageway


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1 INTRODUCTION1.1 Midlothian Council is assessing the feasibility of new road alignment options connecting the A701, A702 and A703 to assist in the preparation of the Main Issues Report for the Local Development Plan. The Council prepared a preliminary assessment of road options: A blue route running from Straiton roundabout generally parallel with the A701 to the west of the park and ride and Straiton Park residential caravan site before turning west towards Pentland Mains. A green route which runs further west than the blue route, cutting across the northern edge of Straiton Bing turning south west between Cameron Wood and Old Pentland towards Pentland Mains. The blue and the green route merge immediately south of Pentland House and turn south west to merge with the A703. A red route connects the A703 north of Seafield Mill to the A702 north of Boghall.1.2 Wardell Armstrong LLP submitted a fee proposal on 7th August 2012 to review the Councils records relating to the land corridor through which the proposed new roads would be constructed.1.3 Wardell Armstrong was commissioned by the Council in a letter dated 21st August to undertake a phased assessment of the road alignment options as detailed in the proposal and in addition to undertake a site walkover of the preferred road alignment.1.4 Our preliminary feasibility study report referenced ED10977-001 was issued on 5th October 2012. That report recommended that the blue route is not geotechnically viable and further work including the walkover survey should be carried out concentrating on a road corridor along the approximate route of the green and red routes.1.5 This addendum report provides a more detailed assessment of road alignment options taking consideration of the topographical, environmental, geological, mining and geotechnical constraints to road construction that were identified in our preliminary report and seen during the site walkover. Estimates have been made for the cut and fill requirements and approximate cost of each of the road options. Potential high, medium and low risk/cost development areas between the proposed road options and the A701 have been identified.

2 LAND OWNERSHIP2.1 Wardell Armstrong was provided by the Council with some details of the landownership through the approximate road corridor under review.2.2 The main landowners are as follows:Midlothian Council Land adjoining the A720 and A701 at Straiton roundabout and the footprint of Straiton Bing.Morston Assets Land to the west of the A701 and north of Straiton Bing subdivided into strips alternatively controlled by Peregrine Edinburgh Ltd and Lansdowne Holdings Ltd.Gibsone Trust Land to the west of Straiton Bing and east of Cameron Wood including Old Pentland cemetery.William R McEwan Pentland Mains Farm and the former landfill.Mrs C Newbould Pentland House, Pentland House Stables and land to the west of Cameron Wood.Trustees of Robert Lawrie & Sons Land to the east of the A703.Scotlands Rural College (SRUC) Land between the A703 and the A701.2.3 Wardell Armstrong contacted all the above landowners to seek permission to access their land for the purposes of a walkover survey. The majority of the landowners agreed to our request.

3 SITE WALKOVER SURVEY3.1 A Wardell Armstrong engineer carried out a walkover survey on 20th November 2012. A photographic record is attached on CD Rom and drawing number ED10977-016 shows the photograph view points.3.2 Access to Straiton Bing was gained from the north of Straiton Residential Caravan Park. The north and eastern areas of the bing are relatively flat at between 140 and 145m AOD and are generally 4 to 5m above the surrounding farm land (photo 13). The majority of this area is covered by scrub vegetation (coarse grass, bramble, gorse, broom and a variety of trees) with occasional blocks of fused blaes (photos 1, 2 and 5). There is a steep slope/cliff from along the southern margin of this area (photos 3, 6 and 7) which borders the Tarmac Topmix plant (photo 9). Ground levels rise from c.150m AOD at the toe to between 160 and 166m at the crest. The steepest sections of the slopes are formed from fused blocks of blaes/burnt shale3.3 In the central area of the bing the ground is more undulating and there is a deep depression with a ground levels falling steeply to a base at c. 136mAOD (photos 4, 8 and 11). There is less vegetation cover of the burnt shale/blaes. It is likely that this was formed by the extraction of blaes/burnt shale for use in construction projects such as the A720. The base may reflect the original ground level prior to formation of the bing.3.4 The digital terrain model (DTM) purchased for the site does not reflect the true topography of Straiton Bing, which is shown in Figure 2 of RPSs report Development Options for Straiton Bing dated 16th April 2009. Their drawing is based on LIDAR Contour data Midlothian Council Survey File No. 258, 03.12.08 (Neg Nt2666/T/258).3.5 The bing is criss-crossed by numerous tracks used by off road motorcycles and dog walkers.3.6 To the west of Straiton roundabout the ground falls quite steeply to a low lying marshy area (photos 17 and 19). To the south of this the ground level rises 3 to 4m up a steep embankment. This appears to be man-made and is possibly associated with localised sand and gravel extraction accessed from a track off the A701 although none is recorded on the historical mapping in this area (photo 20). The earthworks are not discernable on the DTM/LIDAR data for the area. There has been some fly tipping of broken concrete, tarmac and wire, although none of this appears to be recent. Further west there is another marshy area in the vicinity of a former reservoir.3.7 To the west of the park and ride and north of the bing is relatively gently sloping arable farm land (photos 13 to 16, 18, 21, 22 and 24). There is a mine shaft recorded on the apex of a rounded 90 degree field boundary. The soils in this area contained a significant amount of mudstone and siltstone rock fragments suggesting this is a fairly accurate position. Also on this field boundary there was evidence of fly-tipping waste originating from the Straiton Bed Co. Ltd. (Photo 23).3.8 To the north west of the bing there is a triangular shaped low lying very marshy area (photos 25, 26 and 27).3.9 Pasture land rises gently around the western end of the bing towards Old Pentland cemetery and Pentland Road/Damhead (photos 26 and 28). The cemetery is located on a knoll surrounded by a dry stone wall (photos 32, 34 and 47). The south side of Pentland Road/Damhead, opposite the cemetery, is formed by a steep c. 3m high embankment cut into the slope (photo 29). The cutting is not discernable on the DTM for the area.3.10 Cameron Wood runs along the axis of c. 5m high ridge that is likely to be a elongated glacial drift feature. The former quarry at the northern end is overgrown (photo 37) but it is likely that sand and gravel was extracted. The pasture land to the east (photos 31, 33, 35, 40, 41, 42, 43, 44 and 46) and west (photos 38 and 48) of the wood rises initially quite steadily to the south but becomes increasingly steep. Access to the west of the wood was restricted but to the east the margins of the wood (particularly to the south) were formed by bramble, elder, hawthorn and sycamore. More mature trees were found at the southern end of the wood (photo 44) and on the higher slopes.3.11 The pasture land levels out at the southern end of Cameron Wood at c. 170m AOD (photo 45) around Pentland Mains Farm and Pentland House. The former landfill has been restored to pasture land with rough grassland at the margins. The land between the Pentland Burn and the landfill is being infilled (photos 49, 50 and 53) with imported materials to form more level, drained pasture as part of Pentland House Stables. The south western corner of the former landfill is used for storage and processing of timber for biomass fuel and is operated by Pentland Plants Ltd (photos 49 and 52). 3.12 To the south of the landfill and east of the A703 is relatively flat lying arable land (photo 52). There is a slight depression shown on the DTM that corresponds with a pond on the Ordnance Survey mapping. No surface water feature was seen at this location and the low lying area corresponds with the crop marks identified in our preliminary report at this location.3.13 There is a belt of coniferous woodland on the western side of the A703 at a sharp bend in the road (photos 56 and 57) opening out onto rough grassland (photo 60). Further west is a small arable field through which three new water mains were recently laid with valve manholes in the north eastern corner. From here pasture land rises to the west quite steeply from c173m AOD levelling off at c. 195m AOD and rising again to meet the A702 at c.200m AOD (photo 61).

4 ROAD OPTIONS4.1 Wardell Armstrong has prepared four preliminary design options for single and dual carriageway roads from Straiton roundabout to the A703 and a single option for a single carriageway link from the A703 across to the A702. There are three significant constraints that have defined the road alignment options:a) Old Pentland cemetery;b) Cameron Wood;c) Pentland Mains Landfill4.2 The design of all the road options is based on the Nextmap 5m DTM although we have recently been issued with a 2m DTM for most of Straiton Bing and the area to the north. The road layout follows the dual two lane all purpose road given in the Design Manual for Roads and Bridges (DMRB) with a 2m central reservation with, two 3.65m wide lanes, a 1m hardstrip and a 2.5m verge each side. The single carriageway has the same makeup with only one width of lane. The earthworks cut/fill ties in to the DTM at a gradient of 1:3. 4.3 Each of the presented options has been based on the parameters set out in the DMRB. The route of each option was initially reviewed for a design speed of 100kph (62mph), however, where a sharper bend was required to achieve a particular goal or meet a constraint a lower design speed of 85kph (53mph) was also considered.4.4 For each design speed the DMRB Table 3 sets out the desirable radius of bends, superelevation (cross fall around a bend) and the vertical curvature of the road at the brow or base of an incline, which is expressed as a value known as 'k'. For each design speed there are alternative minimum radii, superelevation and k values described as one or two steps below the desirable values. For the horizontal curvature of the bends that we have used in preliminary design, the values are the same for single and dual carriageway. Option 1 - Carriageway to the west of the cemetery and Cameron Wood4.5 The alignment is based on a design speed of 100kph (62mph) with a minimum radius of 510( (one step below desirable with 7% superelevation). Vertical curvature is one step below desirable minimum crest (k=55). See drawing numbers ED10977-003, ED10977-004 and ED10977-005.4.6 The alignment is based on a design speed of 85kph (53mph) with a minimum radius of 255( (two steps below desirable with 7% superelevation). Vertical curvature is one step below desirable minimum crest (k=30). See drawing numbers ED10977-006, ED10977-007 and ED10977-008.Option 3 - Carriageway to the east of the cemetery and Cameron Wood4.7 The alignment is based on a design speed of 85kph (53mph) with a minimum radius of 255( (two steps below desirable with 7% superelevation). Vertical curvature is one step below desirable minimum crest (k=30). See drawing numbers ED10977-009, ED10977-010 and ED10977-011.Option 4 - Carriageway to the east of the cemetery and Cameron Wood and over Pentland Mains Landfill4.8 The alignment is based on a design speed of 85kph (53mph) with a minimum radius of 510( (desirable minimum with 5% superelevation). Vertical curvature is at desirable minimum crest (k=55) for dual carriageway, adopting this value for single carriageway would need to be discussed with the Councils transportation department. See drawing numbers ED10977-012, ED10977-013 and ED10977-014.A703/A702 Link4.9 As the A702 is a single carriageway, only a single carriageway link between the A703 and A702 has been considered. The alignment is based on a design speed of 100kph (62mph). Vertical curvature is one step below desirable minimum crest (k=55). See drawing number ED10977-015 Revision A.4.10 Four junctions/road crossings are required: A new spur of Straiton roundabout; A bridge for Pentland Road/Damhead to pass over the new road; A new roundabout on the A703 at the location of the bad bend north of Seafield Mill; and A T junction or roundabout at the A701 north of Boghall.4.11 Depending on the preferred alignment there may be additional bridges required e.g. access to Pentland House.

5 CONSTRAINTS TO ROAD CONSTRUCTION5.1 In addition to the constraints to road construction detailed in our preliminary feasibility study the following constraints have also been identified.5.2 Topography5.2.1 As detailed in paragraph 3.6, to the west of Straiton roundabout there are earthworks, possibly associated with unrecorded sand and gravel extraction. The route of option 4 cuts though the earthworks.5.2.2 As detailed in paragraph 3.9, Pentland Road/Damhead to the east of the cemetery is cut into the land on its south side by c.3m. The routes of options 3 and 4 pass through this area and would create a c. 4m to 5m deep cutting.

5.3 Superficial depositsMade Ground5.3.1 As detailed in paragraph 5.2.1 the earthworks to the west of Straiton Bing appear to be reworked natural soils but there are some fly tipped materials.5.3.2 As detailed in paragraph 3.6, the land between the Pentland Burn and Pentland Mains Landfill is being infilled with imported materials to form more level, drained pasture. Options 1, 2 and 3 pass over part of this area.5.3.3 We have been provided with a various revisions of drawing Figure 1 showing gas monitoring locations on Pentland Mains Landfill prepared by Fairhurst Consulting Structural and Civil Engineers for Lothian Recycling 1996 Ltd dated 1st September 1999, 23rd October 2000 and 31st July 2001. The drawing is based on an earlier drawing prepared by SAC for the same client referenced 2099-6 Revision F dated 18th January 1999, which appears to have been prepared when the extension site was proposed. The drawings identify: the old tip site in the north and west; the existing tip site in the central and eastern areas (Phases 1 to 3 and 6); the extension tip site in the south (phases 4 and 5, although on the latest drawing upfilled region 6? is recorded between the old tip site and phase 5). Gas monitoring boreholes 1 to 7 incl. located on and around the whole of the landfilled area. Gas spike holes 1 to 21 incl. located on the existing tip in the north east and 22 to 52 incl. located on the extension tip in the south. Proposed and existing drainage and planting; Ground level contours based on a local datum.5.3.4 The contours on the existing tip and those of the original ground level for the proposed extension site suggest that if final formation levels were designed to tie in with existing to the south then upfill would be in the order of 7m thick.Natural Deposits5.3.5 As detailed in paragraph 3.6, to the west of Straiton roundabout is an area of low lying marshy area over which all four road options pass on embankments. Option 1 extends over the additional marshy area further west. Consideration will need to be given to either removal of the organic material and replacement with granular fill (possibly the adjacent earthworks material) or surcharging and draining the marshy area.5.3.6 As detailed in paragraph 3.8, to the north west of the bing there is a triangular shaped low lying very marshy area. Option 3 passes through this marsh and options 1 and 2 pass over the northern limit. Similar remedial methods will need to be considered in this area although the blaes would provide a more localised source of granular material.

5.4 Environmental5.4.1 A badger paw print was seen (photograph 12) to the north east of the bing. As a protected species it will probably be necessary to undertake a badger survey along the preferred route.

5.5 Land-Use5.5.1 As detailed in paragraph 3.11, the south western corner of the Pentland Mains Landfill is used for storage and processing of timber for biomass fuel. Options 1, 2 and 3 cross the northern extent of timber storage where it is restricted by overhead power lines. Option 4 passes through the centre of the storage area.

5.6 Discussion5.6.1 We have already identified Cameron Wood as one of the most significant constraints within the road corridor that we have reviewed. For option 1 the design speed is 100kph (62mph) and the horizontal radius and vertical curvature have been reduced below minimum standards to minimise encroachment into the wood. Nevertheless there is a significant impact on the northern end of the wood cutting through the former quarry before emerging on the western side. The dual carriageway option has a slightly more significant impact. For options 2 and 3 the design speed has been reduced to 85kph (53mph) and the horizontal radius and vertical curvature have been reduced below minimum standards by two and one steps respectively to minimise encroachment into the wood. Option 2 requires an embankment along the western side of the road that encroaches into the wood. However the alignment of option 3 through the bing prevents encroachment into the wood. The design speed of option 4 is also 85kph (53mph) but the horizontal radius and vertical curvature are at or above minimum standards. Option 4 does not encroach into the wood however it does go on to pass through Pentland Mains Landfill.5.6.2 Options 1, 2 and 3 encroach marginally onto Pentland Mains Landfill but option 4 involves a section of cut up to 1.7m through it. Although options 1, 2 and 3 are likely to have less impact this section of any of the routes would need detailed site investigation to assess the depth and nature of the waste. SEPA would also need to be consulted to establish the waste management issues.5.6.3 Options 1, 2 and 3 cross the crop markings. Although this would mean detailed archaeological investigations, it is unlikely that funding would be available to assess this feature from other sources and therefore the more direct routes might be considered a benefit.

6 ROAD CONSTRUCTION COSTS6.1 Cost Basis6.1.1 A high level cost appraisal for the each of the proposed road options has been undertaken and the following assumptions have been used.6.1.2 Due to the limited nature of the outline design and site information this cost appraisal has been based on unit rates available in the approximate estimation section of the SPONS Civil Engineering and Highway Works Price Book 2011. The SPONS unit rates are approximate only and are based on information from sources including engineers estimates, tenders and final account values for a large number of highways contracts. 6.1.3 The unit rates only provide an indicative order of magnitude for works based on statistical frequency norms for road construction schemes of a similar type and nature. A more detailed assessment based on more detailed and accurate information will be required to verify the high level cost appraisal.6.1.4 The rural all-purpose roads unit rates have been used from the SPONS manual. The values shown for the road cost in Table 1 includes for earthworks, structures, drainage, pavements, line markings, reflective studs, footway signs, lighting motorway communications, fencing and barrier works as well as including an allowance for accommodation works, statutory undertakings and landscaping as appropriate to the type and location of the carriageway. The rates do not include purchase of the land, ground remediation or design fees.6.1.5 The main item coverage assumed in the SPONS unit rates includes: 6.1.6 Additionally to the rural all-purpose road unit rate, a feature unit rate has also been included to cover for the associated construction elements such as side roads, interchanges, underbridges, overbridges, culverts, subways, gantries and retaining walls. This feature rate is considered to include for the roundabout junction and bridge structure and therefore these item have not been separately accounted for in the cost table.6.1.7 A review of the SPONS manual unit rates was completed based on available industry data. It was found that the SPONS unit rates were within the typical range of rates used for this type of construction and as such, based on the limited level of design and site data available, were considered reasonable for this high level cost appraisal stage. 6.1.8 The costing presented in Table 1 attached at Appendix B is based on the indicative route options detailed on Drawings ED10977-004 to ED10977-015A incl.6.1.9 In summary the estimated costs for single carriageway options range from 7.18 million to 7.74 million. Estimated costs for dual carriageway options range from 12.53 million to 13.51million. The estimate cost of a single carriageway link from the A703 to the A702 is 2.36 million.6.1.10 Costs might be reduced by using blaes from the bing as a source of road sub-base material. To estimate the volume of blaes that might be available we have assumed that the existing slopes to the north of the Tarmac Topmix plant are extended down to a level of c. 145m AOD i.e. the approximate natural ground level to the east and west and the level. The rest of the bing could be removed to the contours of the agricultural land surrounding it. Following consultation with a contractor who has worked extensively on the West Lothian bings it is likely to be economical to break down and crush the fused blaes blocks and therefore we have assumed that only 10% of materials might be unsuitable. The estimated volume of blaes suitable for use is therefore c. 304,000m3.

6.2 Cut and Fill Estimates6.2.1 For indicative purposes, an assessment of the cut and fill expected requirements for each of the route options has been undertaken and is presented in Table 2 attached at Appendix B. 6.2.2 The quantities detailed are based on the outline horizontal and vertical alignment designs shown on Drawings ED10977-004 to ED10977-015A incl.6.2.3 The cut and fill estimates have been taken directly from the outline highway design model which compares the road surface against the existing digital ground model. No allowance for site preparation, ground remediation or improvement or road construction thickness has been taken into account in completing the assessment.6.2.4 In summary single carriageway options 1, 2 and 4 generate an estimated excess of between c.25,000m3 and 50,000m3 sub-soil and topsoil material. Dual carriageway options 1, 2 and 4 generate an estimated excess of between c.37,000m3 and c70,000m3 sub-soil and topsoil material. Option 3 is constructed on significantly more embankment above existing ground level and requires an additional c.15,500 m3 to c.16,000m3 of granular fill. The single carriageway A703 to A702 link also requires an additional c.4,000m3 of granular fill.6.2.5 The quantities of excess material will be increased if blaes is used to replace unsuitable materials.6.2.6 We have previously suggested that excess sub-soil and topsoil materials might be used to form landscaped roadside bunds to reduce the visual impact of the road or to landscape areas of land that are unlikely to be developed in the foreseeable future e.g. Clippens Landfill site for use as public amenity space.6.2.7 As a guide, using the maximum estimated excess of soils would result in an increase in height of c.0.65m if spread over the whole of Clippens landfill. However, the thickness of topsoil placed would be proportional to the landscape planting; thicker for areas of tree planting and thinner for shrubs and grasses. It is possible that high density planting of thorny trees/bushes such as hawthorn, blackthorn and dog rose could be used to deter the public from entering areas where there is a risk of subsidence. Although the topsoil and subsoil materials are likely to be uncontaminated consideration would need to be given to the effects of landfill gas on any new planting.

7 DEVELOPMENT AREAS7.1 For each of the road options we have estimated developable land areas between the A701 and the new road option, which would act as the defensible boundary to development within the new Local Development Plan. For the purposes of this report developable land is agricultural or brownfield land between the boundaries of existing properties/buildings. The development areas have been sub-divided into areas with a likely low, medium or high risk/cost associated with addressing the constraints that have been identified for road construction, which apply as well to development in general. Low cost/risk Development on greenfield land generally with low gradient slopes and no shallow mining issues. Medium cost/risk Development on Greenfield land with significant areas of steep slope gradients and/or poor ground conditions and/or potential shallow mining issues. High cost/risk Development on brownfield land (former Pentland Oil works and Pentland Mains Landfill) where there is potential for soil or groundwater pollution, landfill gas and/or potential shallow mining and/or poor ground conditions.7.2 Although we are aware that Taylor Wimpey have recently commenced their Phase 1 development at Cameron Gardens, Bilston we have included this area as developable. We have not included the Clippens Landfill site as in our opinion the geotechnical constraints preclude development.Option 17.3 47.1 hectares of low cost/risk, 70.1 hectares of medium cost/risk and 17.5 hectares of high cost/risk. These areas are shown on drawing number ED10977-023.Option 27.4 42.3 hectares of low cost/risk, 67.5 hectares of medium cost/risk and 17.5 hectares of high cost/risk. These areas are shown on drawing number ED10977-024.Option 37.5 41.6 hectares of low cost/risk, 61.8 hectares of medium cost/risk and 18.1 hectares of high cost/risk. These areas are shown on drawing number ED10977-025.Option 47.6 34.4 hectares of low cost/risk, 54.5 hectares of medium cost/risk and 14.1 hectares of high cost/risk. These areas are shown on drawing number ED10977-026.7.7 The cost/risk zoning is likely to change if ground investigations identify additional development constraints or rule out a potential constraint. The area of each zone may alter depending on the road width used (single or dual carriageway), the design standards agreed with the Councils transportation department and detailed design of junctions.

8 CONCLUSIONS AND RECOMMENDATIONS8.1 None of the road alignment options that have been assessed can avoid impact to all three of the main constraints without both a reduction in the suggested 100kph (62mph) design speed of the road and also the minimum vertical and/or horizontal curvature design standards.8.2 Option 4 is the closest to optimum road design as it avoids direct impact on the cemetery and Cameron Wood with only a reduction in design speed to 85kph (53mph), however without a reduction in the design standards it cannot avoid cutting through Pentland Mains Landfill. This option also results in the lowest total potential low, medium and high cost/risk development areas.8.3 Option 1 to the west of Cameron Wood would have the largest visual impact to the Damhead community.8.4 It is possible that direct impact on Cameron Wood could be avoided for other options if embankment slopes can be steepened from the 1:3 design gradients. It is possible that ground investigation might establish that the soil geotechnical parameters will enable steeper slopes to be constructed or retaining structures might be considered.8.4.1 The estimated costs for single carriageway options range from 7.18 million to 7.74 million. Estimated costs for dual carriageway options range from 12.53 million to 13.51million. The estimate cost of a single carriageway link from the A703 to the A702 is 2.36 million. The difference in estimated costs for the various options is less than 10% and considering the number of variables at this stage it is not considered significant.

8.5 Three of the road options would result in a net excess of subsoil and topsoil material up to 70,000m3. This material could be used positively to landscape areas of low development potential such as Clippens Landfill and either side of the proposed road to soften the visual impact. Although Option 3 will generate an excess of topsoil there is an overall net deficit. However it is unlikely that this will be a significant issue as the bing could provide up to c. 304,000m3 of blaes for use as road sub-base material.8.6 The low and medium cost/risk development areas reduce in size gradually from option 1 to option 2 and option 3 ranging from 47 to 41 hectares and 70 to 62 hectares respectively. There is less variation in the high cost/risk development areas, which ranges between 17 and 18 hectares.8.7 Recommendations for further works to assist in finalising a preferred road option: Consultation with Midlothian Council roads department regarding the preferred route and the requirement to reduce road speed and minimum standards to create sufficient developable area to assist funding of the road, minimise the impact on features such as Old Pentland cemetery and Cameron Wood and avoid construction constraints to minimise overall cost. Consultation with SEPA and the landowner regarding the proposals for surrender of waste management licence(s) for Pentland Mains Landfill, associated restoration and the practicalities of road construction through the landfill. Further consultation with the county archaeologist/heritage officer regarding the pros and cons of the route crossing crop marks and proximity of the route to Old Pentland cemetery. Liaison with Damhead Community Council to assess their views on the road options being considered. Undertake an arbouricultural survey of Cameron Wood to enable a better assessment of the impact of an embankment encroaching into the wood. Undertake a topographical survey or purchase more detailed DTM data for the whole of the preferred road corridor. Undertake title deed searches for landownership that is not currently known within the preferred road corridor. APPENDIX A Photographic Record (see separate document)APPENDIX B Table 1 Cost Estimates for Road OptionsTable 2 Cut and Fill Estimates

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road options

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road construcion

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approximate road option

road construction costs

ed10977 electronic reference

number title scale ed10977