7 Corridor Evaluation

Preliminary Options Report Scheme Assessment Report 1 - Constraints Report

7.1 Road Design Categories

7.1.1 Road Design Standard The Design Manual for Roads and Bridges (DMRB) Volume 6; Section 1; TD 9/93 Highway Link Design states that All-Purpose dual carriageways shall be designed to permit light vehicles to maintain the design speed. Subject to traffic conditions, light vehicles can overtake slower moving vehicles throughout. Five categories of dual carriageway are defined, three of which refer to 2 lane all purpose dual (D2AP) carriageway:

Category 5 – This is the lowest category of dual carriageway, which normally represents an alternative to single carriageways. The vertical alignment should follow the topography closely with the horizontal alignment phased to match. All junctions should be at-grade, with roundabouts at the more heavily trafficked intersections, although where economically / environmentally feasible, grade-separated solutions should be provided.

Category 6 – In this category, gaps in the central reserve for turning traffic are not permissible, and major / minor junctions shall not be used. Minor roads shall be stopped up, provided with left in / left out connections, or grade-separated without connection. Major intersection types, which may include roundabouts, will be determined by site conditions, traffic demand, and economic / environmental effect. However, the high costs of delays caused by roundabouts will normally result in more economic grade-separated solutions at the higher end of the range. The combined vertical / horizontal alignments should follow the topography as much as possible, without purposely achieving a “motorway” type flowing alignment.

Category 7a – This is the highest category of Dual 2-lane All-Purpose road, where all intersections, both major and minor, shall be grade-separated. A smooth flowing alignment is required for sustaining high speeds.

Although the specific category to be considered as part of this study was not specified in the brief, Roads Service has indicated a preference for a high standard dual carriageway.

7.2 Review of Preliminary Corridor Options

Given the scale of the project, a large number of potential corridors (links) were identified and are described in Chapter 3. To condense these down to a single preferred corridor, evaluation of the preliminary corridor (link) options has involved a two stage approach.

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Step 1 comprised exclusion of options where major and/or cumulative significant constraints precluded them from further consideration. The remaining corridors that were brought forward to the next step are displayed in Figure 7.1 to 7.3 in this report and Drawings 796036-0800-D-00310 to 796036-0800-D-00329 in Volume 2.

Step 2 involved a detailed evaluation whereby all planning and engineering design criteria were assessed and reviewed against those corridor options that emerged from Step 1. From that detailed evaluation, a preferred corridor emerged. This corridor is displayed on Figure 7.4 to 7.6 in this report and on Drawings 796036- 0800-D-00330 to 796036-0800-D-00339 in Volume 2.

7.3 Step 1 Evaluation of All Corridors

The Step 1 evaluation involved the evaluation of all the corridor links against major constraints, or cumulative significant constraints such as:

• International and national nature Unacceptable environmental impact. conservation designations. • Requirements for extensive Unacceptable social impact and land cost property demolition. • Areas of very high / steep ground. Unfeasible alignment and earthwork.

• Areas of extensive peat. Very expensive to engineer and unacceptable ecological impact.

• Areas of nationally designated Unacceptable environmental impact. landscapes. • Major impact upon river flood Unacceptable flooding impact. plain. • Major impact on sites with cultural Unacceptable environmental impact. heritage value.

Details of these constraints are discussed in Chapters 2, 3, 4 and 5. The options that were consequently excluded during this step and the basis for their exclusion are scheduled below.

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7.3.1 Section 1 New Buildings to South of Strabane Six Corridors were rejected in this section the major constraints were identified as follows:

Node – Node Corridor Link Location Constraint(s) 102-103 West of existing A5 at New Bready archaeological Area (see Buildings to Drumenny via 5.6.2) Bready Foyle floodplain and SAC/ASSI (see 5.6.4) 103-121 West of existing A5 at Foyle floodplain and SAC/ASSI Ballydonaghy to Greenbrae and McKean’s Moss ASSI (see 5.6.4) Peat bog (see 4.3.9) 115-120-116 East of existing A5 at Milltown High ground, high relief (see Burndennet to Ballee via 4.3.9) Artigarvan Proximity to Sperrins AONB (see 5.6.5) 115-109-121 East of existing A5 at Milltown Severance between Burndennet to Greenbrae via Ballymagorry/Artigarvan (see Ballymagorry 5.6.8) Impact on Foyle SAC/ASSI (see 5.6.4) 116-119 Liskinbwee to east of Sion Mills High ground, high relief (see (Carrigullin) 4.3.10) Proximity to Sperrins AONB (see 5.6.5) 121-104-117-111-112 Existing A5 between Greenbrae Impact on floodplains, Mourne and Sion Mills via Strabane River SAC/ASSI (see 4.3.10& 5.6.4) Significant property loss in Strabane and potential impacts on large number of residents (air/noise/severance) (see 5.6.1/2/6)

Table 7.3.1-1: Corridor Links Eliminated in Section 1 Drawing numbers 796036-0800-D-00320 to 00322 show the Section 1 corridor links that were evaluated at the corridor selection workshop.

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7.3.2 Section 2 - South of Strabane to South of Omagh 5 links were rejected from this section:

Node – Node Corridor Link Location Constraint(s) 112-217 Existing A5 from Sion Mills to Adverse impact on towns and north of Ardstraw Heritage, especially Sion Mills and Victoria Bridge (see 5.6.2) 213-214 Douglas Bridge to east of Encroaches into Sperrins AONB Mountjoy (see 5.6.5) 207-214 Mountjoy to node 214 214-216 East of Mountjoy to east of Proximity to Sperrins AONB Omagh (see 5.6.5) 208-211 Existing A5, from Fairy Water Significant property loss in bridge to south of Omagh Omagh and potential impacts on large number of residents (air/noise/severance) (see 5.6.1/2/6)

Table 7.3.2-1: Corridor Links Eliminated in Section 2 After the elimination of node to node link 213-214 a further corridor link was developed following the nodes 218-213-208. Geographically, heading south from Douglas Bridge, this link runs east of the Strule River before connecting into the existing A5 corridor at Newtownstewart. Drawing numbers 796036-0800-D-00323 to 00325 show the Section 2 corridor links that were evaluated at the corridor selection workshop.

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7.3.3 Section 3 - South of Omagh to Aughnacloy Of the initial 22 corridor link options in section 3, 18 links were removed from further consideration; although a further 4 potential hybrid corridors were identified for inclusion. (Note some node links in the following table cover more than one corridor)

Node – Node Corridor Link Location Constraint(s) 319 Tattykeeran Deroran Bog SAC / ASSI (see 5.6.4) 211-313 Omagh Significant property loss in Omagh and potential impacts on large number of residents (air / noise / severance) (see 5.6.1/2/6) 321-324 Martray House Martray House and Lough (see 5.6.2) Slievemore Ridge – excessive earthworks (see 4.3.15) 306-308 West of Aughnacloy - Ravellea The Thistle, Ravellea (see 5.6.2) Substantial low-land raised peat bog (see 4.3.16) River Blackwater floodplain (see 4.4.8)

216-313 Ballynamullan, Golan, Substantial low-land raised peat Donaghanie bog (see 4.3.14) 317-318 210-301 Seskinore, Tullyvally, Tattyreagh Substantial low-land raised peat 210-325 Glebe, Mullaghmore bog (see 4.3.14)

Table 7.3.3-1: Corridor Links Eliminated in Section 3 Following the elimination of these nodes an additional link and a further three potential hybrid corridors were identified for inclusion, development and discussion at the workshop. They are as follows:

S3H10: Nodes 203 – 301 – 325 – 315 – 316 – 306 – 307 – 308

An additional link was identified linking nodes 301 - 325 – 315. Geographically it extends from Seskinore eastwards to Letfern and on to Curr on the existing A5.

S3H11: Nodes 210 – 312 – 313 – 314 – 315 – 316 – 306 – 307 – 308

S3H12: Nodes 210 – 312 – 318 – 320 – 321 – 322 – 316 – 306 – 307 – 308

These two corridors are hybrid forms of the original corridors S3B01 and S3H06 respectively, which was removed because it went to the west of Aughnacloy (nodes 306-308 - see above). This corridor instead extends to the east of Aughnacloy passing through nodes 306 – 307 – 308.

S3H13: Nodes 210 – 312 – 318 – 320 – 321 – 323 – 307 – 308

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This corridor is a hybrid form of the original corridor S3H06, which was removed because it went to the west of Aughnacloy (nodes 306-308 - see above). This corridor instead extends to the east of Aughnacloy passing through nodes 306 – 307 – 308, having passed just west of Ballyreagh and east of Martray Lough.

Drawing numbers 796036-0800-D-00326 to 00329 show the Section 3 corridor links that were evaluated at the corridor selection workshop.

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7.4 Step 2 - Detailed Assessment of Remaining Feasible Corridors

The corridor options remaining from Stage 1 were then subject to further review and evaluation.

Each design discipline produced a matrix showing the constraints against the viable corridors for each section of the scheme. These matrices are provided in Appendix C. The constraints and their impacts were presented to a workshop of 25 people drawn from all the designer’s technical design disciplines of the designer, the cost manager and the Roads Service. The key disciplines represented comprised:

• ENGINEERING,

o Geotechnical,

o Flooding and Drainage,

o Alignment feasibility and Buildability,

o Structures,

o Utilities,

• ENVIRONMENTAL IMPACTS,

• TRAFFIC FLOWS AND BENEFITS,

• COST.

A semi quantitative assessment of all the factors was carried out, to ensure that no factor was given undue high or low influence in this process. The outputs from this were used to encourage a debate of the corridors so that the assessment would be unbiased and yet also be realistic.

The following tables summarises the principal constraints from the workshop, using the nine sub-sections adopted to describe the options in Chapter 3. This information was then combined as a conclusion at the end of each section, with an assessment of the traffic and economic benefits associated with key alignment strategies, to determine those options which should form part of the preferred corridor. Clearly, it was appropriate that corridors should join up between sections, which sometimes defined whether a corridor should be rejected.

In the table, corridors are generally described in order, from west to east.

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7.4.1 Section 1: New Buildings to South of Strabane

Node- Description Key Constraints Keep Reject Node 9 8 Link Note, - In section 1, where corridors impact on the Foyle floodplain this affects ecology, water quality, flood protection and soft ground conditions Sub-Section 1A New Buildings to Cloghcor 101- Existing A5 from Bready Archaeology site and Heritage Identity Area 9 102-108 New Buildings to to the west. Loughneas via Soft deposits & Foyle Floodplain SAC/ASSI and Bready Foyle Environment Identity Area to the west, Crossing of Burn Dennet floodplain. Landfill site. Noise, air quality receptors (i.e. residents) in villages along the A5. Existing roadside services including fibre optic. Trunk water main. Kittybane Landfill north of New Buildings 101- East of existing High ground / Greater earthworks / Significant rock 9 107-108 A5 at New excavation on Gortmonly Hill. Buildings to Gravel extraction in south. Loughneas via Crossing of Burn Dennet floodplain. Eden Kittybane Landfill north of New Buildings 101- Variant, East of High ground / Greater earthworks / Significant rock 9 107- existing A5 at excavation on Gortmonly Hill. 115 New Buildings to Gravel extraction in south. Milltown Kittybane Landfill north of New Buildings Burndennet via Eden 114- East of existing Steep terrain/ Significant rock excavation and issue 8 115 A5 at New of chasing slopes in Burngibbagh Valley/ Tully Buildings to Valley. Milltown Gravel extraction in the south. Burndennet Landfill site south east of New Buildings. Overhead electric cables. Constrained to the west of New Buildings by the River Foyle Tullyvalley Kittybane Landfill north of New Buildings. Tully Valley Environmental Identity Area. Conclusion – The corridor should avoid the Foyle floodplain, the Bready archaeological area where possible and the steep terrain to the east. The preferred corridor could run immediately east of the current alignment but may run to the west where above constraints permit and could be a combination of the best of all the western corridors bar the furthest eastern one. Any on-line or near on-line corridor would have to take account of noise/air/vibration impacts on the villages along the existing road. There are constraints imposed by the River Foyle, sewage works and high ground to any route around New Buildings

Sub-Section 1B - Cloghcor to North of Strabane 108- Existing A5 at Noise and air quality receptors in villages along the 9 109- Loughneas to A5. 121 Greenbrae via Soft deposits & Foyle Floodplain SAC / ASSI and Ballymagorry Foyle Environment Identity Area to the west. McKeans Moss peat bog ASSI. 115- East of existing Strabane Glen ASSI. 8 109- A5 at Milltown Significant rock excavation / earthwork climbing to 122 Burndennet to high ground at Tullyard. Tullyard via Gravel extraction area in the north. Ballymagorry

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Node- Description Key Constraints Keep Reject Node 9 8 Link 108- East of existing Strabane Glen ASSI. 9 109- A5 at Significant rock excavation / earthwork climbing to 122 Loughneas to high ground at Tullyard. Tullyard via Possible impact on Foyle Floodplain Environmental Ballymagorry Identity Area in the north west. Possible impact on McKeans Moss peat bog ASSI in the north west. Conclusion – This section should avoid impacting on the villages and must join up with Section 1A at node 108 or 115. A corridor either side of Ballymagorry was feasible (more difficult to the west due to the Foyle flood plain & McKean’s Moss), which could diverge southwards to either side of Strabane.

Sub-Section 1C - North of Strabane to South of Strabane 121- West of existing Landfill/ gasworks/ abattoir contaminated land in 9 104-105 A5 at Greenbrae Strabane. to the west of Flooded quarry and Orchard Road Landfill south Glebe via the west of Strabane. west of Strabane River Foyle / Mourne River Floodplain SAC/ASSI and Foyle Environmental Identity Area and associated soft deposits. Crossing of Mourne River SAC. Heritage value. Impact on potential development area on southern edge of Strabane. Constrained on Finn River SAC bank and possible loss of property. NIW water & sewers. 121- Existing A5 Constrained by development (loss of property). 9 104- between Potential impacts on large number of residents (air 111-112 Greenbrae to quality / noise and vibration / severance). north of Sion Landfill/ gasworks/ abattoir contaminated land Mills via north of Mourne River. Possible contamination in Strabane railway corridor south of Mourne River. Crossing of Mourne River SAC. Potential need for retaining structures Less impact on Foyle Flood plain. NIW water & sewers. 122- Tullyard to Sion Strabane Glen ASSI. 9 116- Mills via Steep terrain / significant rock excavation at 117- Liskinbwee and Knockavoe Hill. 111-112 southern Abandoned mine adit (lead trial) Strabane Mourne River SAC and floodplain. Crossing of Mourne River. Less impact on community issues in Strabane. Overhead electric cables. 122- Tullyard to east Strabane Glen ASSI. 9 116- of Sion Mills Steep terrain / significant rock excavation at 117-118 (Grevenue Knockavoe Hill. Bridge) via Soft ground South of Strabane. Liskinbwee and Significant earthwork for Pattens Glen crossing. southern Local Impact on Mourne SAC at Pattens Glen. Strabane Overhead electric cables. 122- Tullyard to east Strabane Glen ASSI. 9 116-119 of Sion Mills via Steep terrrain / Significant rock excavation at Liskinbwee Knockavoe Hill. Soft ground south of Strabane. Significant earthwork for Pattens Glen crossing. Overhead electric cables.

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Node- Description Key Constraints Keep Reject Node 9 8 Link Conclusion – The relationship of Strabane to the River Foyle to the west and to the steep slopes rising to the Sperrins to the east constrains options within this part of the engineering study area, whilst existing development is a constraint to a potential on-line option. There are significant engineering and environmental impacts associated with all options at Strabane, ranging from ecological and flooding issues in the west, to community issues on-line and a combination of several issues on the high ground route east of Strabane. The western (riverside) options may potentially conflict with EU nature conservation objectives. The traffic and economic analysis indicated that westerly alignments would give a substantially greater benefit than eastern ones, as well as providing the strategic link to Co Donegal at Lifford. In light of the complexity and potential impacts associated with all three principal corridors it is recommended that they should all retained, to be assessed in more detail.

Table 7.4.1-1: Summary of Corridor Link constraints in Section 1 7.4.2 Section 2: South of Strabane to South of Omagh

Node- Description Key Constraints Keep Reject Node 9 8 Link Sub-Section 2A - South of Strabane to Douglas Bridge 105-201 Glebe to the Minor community impacts on Glebe village. 9 north west of NI Water service reservoir. Ardstraw 113-217 Glebe / Sion Constrained by development at Sion Mills and 9 Mills to the north Victoria Bridge plus local steep terrain at Seein of Ardstraw Bridge. Impact on noise, air quality sensitive receptors, at Sion Mills & Victoria Bridge. Proximity to River Mourne SAC. 118- East of Sion Very constrained by development, River Mourne 8 212- Mills to west of and local terrain near Douglas Bridge. 204 Douglas Bridge Proximity to Mourne River SAC. via node 212 Ancient woodland. Loss of Mourne floodplain. 119-218 East of Sion Proximity to Sperrins AONB. 8 Mills to Douglas Higher ground/ increased earthworks. Bridge Upland peat deposits in the east. Conclusion – Corridors to east of River Mourne are more constrained than the west bank. Avoid taking corridor through the villages due to environmental impacts and severance. Adopt the better of the two links west of Sion Mills and the river, avoiding high ground in the far west.

Sub-Section 2B – Douglas Bridge to South of Mountjoy 201-202 North west of High ground /steep terrain / Rock excavation on 8 (W) Ardstraw to through the hills. Kilmore via the Very soft ground in Baronscourt valley and Fairy west of Bessy Water. Bell Impact on Bessy Bell Environmental Identity Area. Fairy Water bogs and floodplain in far south. Forestry in Baronscourt area Does not achieve traffic connection to Plumbridge/Gortin

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Node- Description Key Constraints Keep Reject Node 9 8 Link 201- North west of Castle. 9 205-202 Ardstraw to Local high ground / rock excavation & construction Kilmore via the on steep slopes on shoulders of Bessy Bell east of Bessy Raised peat bog in the far south Bell Gravel extraction at Deerpark. Noise, air quality, sensitive receptors at Newtownstewart & Ardstraw. Construction on steep slopes south of Newtownstewart. 217- The existing A5, Impact on Mourne River floodplain. 9 204- from north of Mourne SAC / ASSI. 213- Ardstraw to Gravel extraction at Deer Park 206- Fairy Water Opportunity to use / modify existing 207- bridge Newtownstewart Bypass bridges. 208 Tully Bog ASSI, SAC and Grange Wood ASSI. Noise, air quality sensitive receptors at Newtownstewart and Mountjoy. Proximity to Sperrins AONB. Construction on steep slopes in Strule Valley. Knockmoyle landfill. Overhead electric cables. Trunk water main. Conclusion – The Baronscourt (western) route is difficult to engineer and is environmentally sensitive therefore it has been rejected. Making use of the Newtownstewart bypass should be considered in detail, though widening may be difficult due to land use constraints. South of Newtownstewart a higher level route on the West side of the Strule is preferable to the low level route. Connecting these may be difficult, so a corridor either side of Newtownstewart then on west side of River Strule at both levels are to be carried forward for more detailed assessment.

Sub-Section 2C – South of Mountjoy to South of Omagh 202-203 Kilmore to node Rising ground with rock excavation. 9 203 some 4km Cavancaw gold mine. south-west of Minor air quality / noise impact on Clanabogan. Omagh 219- Fairy Water to Minor air quality / noise impact on Gillygooly. 9 209-210 node 210 some Tully Bog ASSI, SAC 3km south west Major crossing Fairy Water floodplain. of Omagh 208- Fairy Water Greenway landfill. 8 215-216 bridge to east of Killyclogher reservoirs. Omagh Rising ground / rock excavation in the far east. Sperrins AONB. Soft peat to East. Crossing of Strule and flood plain, Tully Bog ASSI, SAC Minor community impact on Omagh. Lisnamallard House. Conclusion: Avoid high ground to east and far west. Keep corridor close to western edge of Omagh on traffic and engineering grounds, but avoid Fairy Water / Strule confluence due to flood plain and environmental sensitivity if possible. Traffic model indicates high desirability for connection to existing road immediately North of Omagh. The corridor to West of Omagh with intersection of A32 (Dromore Rd) has greater traffic benefit than East corridor.

Table 7.4.2-1: Summary of Corridor Link Constraints in Section 2

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7.4.3 Section 3: South of Omagh to Aughnacloy Node- Description Key Constraints Keep Reject Node 9 8 Link Sub-Section 3A - South of Omagh to Seskinore 203-301 Clanabogan south Significant Owenreagh & Fintona River 8 west of Omagh to floodplains. south west of Ancient woodland. Seskinore Extensive raised peat bog 110kV overhead cables crossing on pylons 210- South west of Raised peat bog. 9 314-315 Omagh to Curr via Minor air / noise impact on Gortaclare/Moylagh. Gortaclare/Moylagh Significant Owenreagh/Drumragh River Floodplains. Trunk water main crossing. Concentration of N.I. Water reservoirs/Waste Water Treatment Works 110kV overhead cables crossing on pylons 210- South west of Raised peat bog. 9 312- Omagh to Curr via Constrained on existing A5 by houses 313- Drumragh, Significant Drumragh River Floodplain. 314-315 Tullyheeran and Trunk water main crossing. Gortaclare/Moylagh 110kV overhead cables crossing on pylons 210- South west of Raised peat bog. 8 312- Omagh to Derroar, Sperrin Hinterland. 318-320 via Drumragh and Significant Drumragh & Cloghfin River Floodplain. east of Camowen Trunk water main crossing. 110kV overhead cables crossing on pylons 203- Clanabogan, south Owenreagh River Floodplain. 8 301- west of Omagh to Ancient woodland. 325-315 Curr via Seskinore Extensive raised peat bog and Letfern 110kV overhead cables crossing on pylons Conclusion – There are extensive peaty areas south and east of Omagh and around Seskinore Forest. These will be difficult to steer a route through and are best avoided. The three tributaries of the Strule have local flood plains, which affect the far western and eastern corridors, which are therefore rejected. Traffic benefits are greatest if a tie in to the existing road is made immediately south of Omagh, which indicates a “tight” line to the south west of the town is preferable. Sub-Section 3B – Seskinore to North of Ballygawley / Augher 301- Seskinore to Rock excavation through Slievemore Ridge with 8 302- Longridge, via major earthworks. 303-304 Eskragh and south Gravel works at Eskragh. west of Beltany Hill Significant Eskragh River Floodplain Trunk water main crossing. Potential soft deposits of Eskragh Floodplain 315- Curr to Longridge, Rock excavation through Slievemore Ridge with 8 310- via Tamlaght and major earthworks. 303-304 south west of Significant Seskinore River Floodplain Beltany Hill Trunk water main crossing

315- Curr to Longridge Existing valley through ridge reduces scale of 9 310-304 via Tamlaght earthworks. Significant Seskinore River Floodplain 315- Curr to Callahan Existing valley through ridge reduces scale of 9 310-326 via Tamlaght earthworks. Tycanny Archaeological Identity Area. 315-316 Curr to Tullylinton Existing valley through ridge reduces scale of 9 via existing A5 earthworks. Retaining wall needed to avoid houses south of Garvaghy. Slievemore Environmental Identity Area. Noise, air quality sensitive receptors and severance impact at Garvaghy.

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Node- Description Key Constraints Keep Reject Node 9 8 Link 320- Derroar to Rock excavation through Slievemore Ridge with 8 321- Tullylinton via major earthworks. 322-316 Tullyglush and Major Cloghfin River Floodplain north of Findrum Gravel works at Altamuskin. Blanket bog on hill tops. Floodplain at Sixmilecross. Slievemore Environmental Identity Area. NI Water reservoirs. Concentration of N.I. Water reservoirs/Waste Water Treatment Works 320- Derroar to west of Rock excavation through Slievemore Ridge with 8 321- Ballyreagh via major earthworks. 322-323 Tullyglush Major Cloghfin River Floodplain Gravel works at Altamuskin. Blanket bog on hill tops. Floodplain at Sixmilecross. Slievemore Environmental Identity Area. NI Water reservoirs. Concentration of N.I. Water reservoirs/Waste Water Treatment Works Conclusion: Avoid archaeological areas at Tycanny and Knockmany. Eastern routes on very high ground are unfeasible due to blanket bog, gravel extraction and scale of earthworks required. Any route crossing the Slievemore ridge will have significant earthworks – make use of existing valleys (used by A5 and other lanes) to reduce size of earthwork and impact thereof. Sub-Section 3C – North of Ballygawley/Augher to Aughnacloy 304- Longridge to Moy Length route across drumlins and soft inter- 8 305- Bridge via Lisdoart, drumlin soils. 306- Cavankilgreen and Two Wastewater Treatment Works. 307-308 Glencull Significant Roughan, Annaghilla and Ballygawley Water Floodplain Blackwater and Ballygawley Water bridges. Ballygawley archaeological area 326- Culnaha to Moy Tullyvar landfill. 9 311- Bridge via Ballygawley Archaeological Identity Area. 305- Crossboy, Lisdoart, Drumlins and soft inter-drumlin soils. 306- Cavankilgreen and Blackwater and Ballygawley water bridges. 306- Glencull 307-308 Ballygawley archaeological area Significant Ballygawley Water Floodplain Trunk water main crossing Concentration of N.I. Water reservoirs/Waste Water Treatment Works 316- Tullylinton to Moy Tullyvar landfill. 9 306- Bridge via Noise and air quality sensitive receptors and 307-308 Cavankilgreen and severance at Ballygawley. Glencull Significant Ballygawley Water floodplain. Drumlins and soft inter-drumlin soils. Trunk water main crossing. Blackwater and Ballygawley Water bridge. Ballygawley archaeological area 323- West of Ballyreagh Cost of rock cut and significant earthworks in high 8 307-308 to Moy Bridge via ground east of existing alignment. Glencull Possible peat to south west of Aughnacloy. Trunk water main crossing. Crossing of Ballygawley Water.

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Node- Description Key Constraints Keep Reject Node 9 8 Link Conclusion: Need to avoid Tullyvar landfill and the high ground in the far east due to associated cost of earthworks. Western routes and all remaining (central) routes will encounter drumlin terrain with widespread soft ground as well as the Ballygawley archaeological area. All corridors currently take east route around Aughnacloy, though traffic benefits may be greater if a western route is taken. There may be archaeological and peat constraints associated with the Blackwater Valley and drumlins in County Monaghan. South of the border the N2 is the subject of a separate assessment and liaison is ongoing with the NRA and Monaghan Co Co to develop a continuous corridor which has least effects on the border communities.

Table 7.4.3-1: Summary of Corridor Link Constraints in Section 3

7.5 Emerging Draft Preferred Corridor

From the workshop corridor filtering exercise, the following corridor began to emerge as worthy of more detailed assessment at the next stage in the project. Refer to drawing numbers 796036-0800-D-00330 to 00339 in Volume 2 and Figures 7.4 to 7.6 below.

From New Buildings to Ballymagorry, the corridor runs to either side of the existing alignment of the A5, but avoiding where possible the River Foyle SAC and floodplain as well as the Bready archaeological area. The high ground of the Sperrin foothills limits the eastern edge of the corridor. A crossing of the Burn Dennet will be required at Cloghcor and a more easterly crossing offers a more viable solution.

At Ballymagorry the corridor widens to allow possible routes either side of the village as well as the three principal options at Strabane which are east, west or on-line. The corridor is narrow on the west side of Ballymagorry to limit incursion into the Foyle floodplain and associated ASSI.

At Strabane, the preferred corridor is defined on the west side by the banks of the rivers Foyle and Finn and on the east by the lower slopes of Knockavoe Hill. This allows further study of routes east of, west of or on-line through Strabane.

South of Strabane the corridor narrows again and follows relatively low-lying land west of the Mourne River and Sion Mills, but avoiding higher ground in the far west. The corridor continues in a south easterly direction, to the west of Victoria Bridge, but east of Ardstraw.

South of the confluence of the Rivers Derg/Mourne/Strule, the corridor widens to encompass both banks of the Strule River through Deerpark and Newtownstewart, incorporating the existing Newtownstewart bypass, but allowing assessment of an alternative route south west of the local town. This avoids the high ground of Bessy Bell and the steep terrain of the Baronscourt estate.

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Continuing south of Newtownstewart, the corridor narrows through the Strule Valley, but keeping to the west bank of the river, taking a narrow and steep sided corridor between the AONB and Bessy Bell.

At Mountjoy, the corridor takes a broad swing around the west and south west side of Omagh, but avoiding the Cavancaw gold mine. Connections to the existing A5 north and south of Omagh will be important and together with the benefits of connecting to the A32 largely define the preferred corridor around the town.

South of Omagh, the broad corridor runs parallel to and slightly to the west of the existing A5. Near Roscavey, the corridor splits; the northeastern branch is relatively narrow and continues to follow the existing A5 to Garvaghy and Ballygawley; the southwestern branch swings southwards towards Newtownsaville and an alternative shallow valley through the Slievemore ridge.

The two branches recombine in the low lying drumlin landscape of the Clogher Valley to the south of Ballygawley and take a narrow loop, close to and around the eastern edge of Aughnacloy, connecting with the existing Blackwater Bridge for connections to Monaghan.

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7.6 Recommended Further Amendments

At the workshop, it was apparent that the traffic modelling indicated that benefits may be greater if a western alignment is taken around Aughnacloy, connecting to the Republic of Ireland. However the “Thistle” significantly constrains this option immediately west of the village. It was concluded that an additional variant corridor further west, between the Thistle and Favour Royal should be considered further, diverging from corridor link 326-308 and meeting the Irish border, some distance west of the village. This would allow greater flexibility for cross border options.

7.7 Refinement of the Draft Preferred Corridor after the workshop

Following the Corridor Selection Workshop described above, a meeting was held on 5th August 2008 in Roads Services Omagh Office to rationalise the Draft Preferred Corridor (DPC).

The purpose of the meeting was to refine and rationalise the extents of the Emerging Draft Preferred Corridor from the workshop, in order to keep key options open for a more detailed Stage 2 Assessment, while not eliminating potentially suitable routes that could be developed within the identified major constraints.

The review was carried out utilising the full range of constraints information available at the Corridor Selection Workshop, in a GIS format and utilising the subsections described previously. Drawing numbers 796036-0800-D-00340 to 00349 in Volume 2 and Figures 7.7 to 7.9 detail the refined preferred corridor.

7.7.1 Sub-Section 1A - New Buildings to Cloghcor It was agreed that a single carriageway link tying in to the north of New Buildings should be investigated as part of the Stage 2 Assessment. The Draft Preferred Corridor was therefore extended to the north and widened slightly around New Buildings, to allow both a western and eastern link to be developed.

To the south of New Buildings, it was identified that the potential for a western alignment in between the existing A5 and the River Foyle floodplain should be retained to allow for an off-line alignment west of Bready, but east of the floodplain, to be investigated as part of the Stage 2 Assessment.

To the east of Bready the eastern edge of the DPC was realigned to the west to approximately follow the contours at the base of Gortmonly Hill, thus avoiding the higher ground and reducing the potential for significant earthworks. Once around the base of the hill the realigned eastern edge of the DPC continued southwards avoiding the western edge of Donagheady.

7.7.2 Sub-Section 1B - Cloghcor to North of Strabane Through Section 1B the eastern edge of the DPC was realigned to the west. This ensured that the DPC avoided both the high ground of Sixpenny Hill and the settlement of Artigarvan. It also allowed for a route option to the west of Ballymagorry to be developed in the Stage 2 Assessment.

The western edge of the DPC was also realigned to avoid the Area of Special Scientific Importance between Ballydonaghy and Leckpatrick.

7.7.3 Sub-Section 1C – North of Strabane to South of Strabane The western edge of the DPC was realigned to exclude the sewage treatment works at Greenbrae. It was also realigned locally to follow the eastern bank of the Rivers Foyle and Finn.

7.7.4 Sub-Section 2A – South of Strabane to Douglas Bridge It was agreed that it was not feasible to route the proposed road through Sion Mills on the existing A5 and maintain the high speed strategic link. The eastern edge of the DPC was therefore realigned to follow the west edge of the developed area Sion Mills. Immediately south of Sion Mills the eastern edge was realigned to the east to accommodate a potential alignment to the east of an area of ribbon development occupying the central area of the DPC.

The western edge of the DPC was realigned to the east to avoid hilly rising terrain and thus reduce the potential for significant earthworks.

7.7.5 Sub-Section 2B – Douglas Bridge to South of Mountjoy The section between Newtownstewart and Mountjoy was realigned to the Strule River boundary to allow for an online improvement and to limit the impact on the Area of Outstanding Natural Beauty to the east.

The western edge of the DPC was realigned to match from Section 2A realignment, and avoiding the village of Ardstraw.

In addition, the narrow section on the slopes of Bessy Bell was widened to the west to include an area of plateau on the slopes of the hill. This was done following site visits, which identified a potential route through the area. In the area just north of Omagh, the eastern edge of the DPC was realigned to the east to accommodate a potential alignment to the east of the Tully Bog SAC.

7.7.6 Sub-Section 2C - South of Mountjoy to South of Omagh The eastern edge of the DPC was modified to better reflect the development limits of Omagh and an area of ribbon settlement around the western edge of the town.

The western edge of the DPC was realigned eastwards in order to avoid Lough Muck and areas of bog in section 3A (see below).

7.7.7 Sub-Section 3A - South of Omagh to Seskinore The western boundary of the DPC passed through some significant constraints such as Lough Muck, areas of bog and ribbon settlement.

It was agreed that the cumulative effect of the above constituted a major constraint and that realigning the edge further to the west would have a negative effect on the likely traffic flows on any proposed route. The western edge of the DPC was therefore realigned further to the east.

7.7.8 Sub-Section 3B - Seskinore to North of Ballygawley / Augher This section of the DPC runs generally west to east and has a “cut-out” unfeasible section within it.

The southern boundary of the DPC was moved northwards to avoid an area of steep terrain on the Slievemore Ridge and to better follow the contours of the existing ground thus reducing the potential for significant earthworks.

The northern branch section was realigned onto the existing A5 to avoid significant geotechnical, topographical and development constraints to the south.

The northern boundary in the same area was modified to allow for a potential alignment through the pinch point to the north of the existing A5 near Garvaghy, although there are a significant number of individual properties in this area.

7.7.9 Sub-Section 3C - North of Ballygawley/Augher to Aughnacloy The northern edge of the DPC was realigned northwards to accommodate a potential route to the north of an area of development land and a landfill site.

The DPC was also adjusted to avoid the development extents in Aughnacloy.

The section of DPC was retained to the west of Aughnacloy was retained while consultations with National Roads Authority continue and the route of the N2 improvement in the Republic of Ireland is considered. It is recognised however that there are significant constraints in this area.

7.8 Further Refinement of the Draft Preferred Corridor

At a further meeting held on 5th September 2008 a number of further minor, discreet amendments to the Draft Preferred Corridor (DPC) were agreed.

7.8.1 Section 1A (New Buildings) Following discussions with Roads Service Northern Division regarding the proposals for the A6 near Londonderry and to further facilitate the single carriageway link to the north of New Buildings the DPC was extended to the north and widened to the east.

7.8.2 Section 1B (Cloghcor/Ballymagorry) The western edge of the DPC was previously aligned locally around the eastern edge of a wooded area between Cloghcor and Ballymagorry. It was considered that this resulted in an area of land within the DPC that could not be utilised in a Stage 2 route because of the geometric requirements for a dual carriageway alignment. The edge was therefore amended in this area to ensure the maximum amount of usable area within the corridor.

7.8.3 Section 1C (Strabane) To the west of Strabane the edge of the DPC was realigned westwards to tie in with the eastern edge of a sewage treatment works in order to maximise the space available for a potential western route option.

7.8.4 Section 2A (Sion Mills) The eastern edge of the DPC was realigned to better reflect the western edge of the Sion Mills development extents, thus providing additional space for a potential route between Sion Mills and Glebe.

7.8.5 Section 2C (Clanabogan) The south west edge of the DPC was realigned to better reflect the north eastern edge of the Clanabogan development extents.

7.8.6 Section 3B (Garvaghy) The northern edge of the DPC was realigned to follow the existing A5, thus better reflecting the edge of the Garvaghy development extents.

7.8.7 Section 3C (Ballygawley) The northern edge of the DPC was realigned to better reflect the southern edge of the Ballygawley development extents.

7.8.8 Section 3C (Aughnacloy) The western edge of the DPC was realigned to better reflect the eastern edge of the Aughnacloy development extents.