Appendix 16C Baseline Data

A5 Western Transport Corridor Volume 3 – Appendices

APPENDIX 16C BASELINE DATA

Surface Water

Designations

There are a number of areas in close proximity to the proposed route which support important habitats and wildlife, including areas requiring special protection under national or European legislation. A number of these designated sites are dependent on the quality of the water environment and are detailed in Table 16C.1

Table 16C.1 Designated Sites Dependent on the Quality of the Water Environment

Name Basis of Designation

River Foyle & Tributaries The SAC is designated for its habitats of plain to montane levels with the Ranunculion SAC fluitantis and Callitricho-Batrachion vegetation and the largest population of Atlantic Salmon in Northern Ireland (15% of the estimated national spawning numbers). The river is notable for the physical diversity and naturalness of the banks and channels, especially in the upper reaches, and the richness and naturalness of its plant and animal communities. The presence of otter is a subsidiary qualifying feature.

River Finn SAC The River Finn SAC is located adjacent to the River Foyle & Tributaries SAC, within the same watercourse, comprising the designated area on the Republic of Ireland side of the border. The SAC is designated for its habitats of Oligotrophic Waters, Wet heath, Blanket Bogs, Transition Mires, as well as its Atlantic Salmon and Otter species. The northern section of this site also comprises the River Foyle, Mongavlin to Carrigans Proposed Natural Heritage Area (pNHA).

McKeans Moss ASSI The most north-western example of lowland raised bog in Northern Ireland. The intact bog surface exhibits a well defined dome with characteristic vegetation and structural features, including hummock and lawn complexes and small shallow pools. Sphagnum species are well represented. The periphery of the bog has been extensively cut for turf in the past. The cutover area is now dominated by mature woodland and scrub.

Strabane Glen ASSI Strabane Glen is a narrow valley supporting a calcareous wet woodland which is atypical of this region and its presence is related to the underlying geology.

Tully Bog SAC & ASSI Tully Bog is an isolated lowland raised bog lying in a shallow hollow within the former floodplain of the Fairy Water River. The central intact dome supports a small pool system with a good hummock and hollow development on the bog plain. The centre of the bog has a small raised drumlin, with birch woodland growing on it. The rare bog- mosses Sphagnum imbricatum and S. fuscum are present.

Name Basis of Designation

Grange Wood ASSI Grange Wood is a calcareous wet woodland occurring on the north-eastern flank of Bessy Bell Mountain and partially overlying an isolated outcrop of Dungiven limestone. The wood is largely comprised of a low, multi-stooled Hazel canopy with occasional Ash standards over a diverse base-rich ground flora. Frequent exposed rocky outcrops and boulders are covered by a luxuriant growth of mosses, particularly on the upper slopes. The lower slopes are waterlogged with extensive flushing and in these areas Willow and Alder predominate.

Under the Water Framework Directive the major rivers and their tributaries have also been classified in terms of their ecological status, with classifications ranging from ‘Good’ to ‘Poor’.

Surface watercourse catchments

The main surface water catchments with which the Proposed Scheme would interact, are described below. These are shown on Figure 16.1 and in more detail on Figures 16.2-16.18.

Lower Foyle Catchment

The River Foyle catchment area is approximately 2,890km2 and extends into the counties of Londonderry, Tyrone and Donegal. The major tributaries of the Foyle include the Burn Dennet, Glenmornan, Finn, Mourne, Strule, Owenkillew, Derg, Fairy Water, Camowen and Drumragh Rivers.

The northern section of the proposed route lies within the Lower Foyle Catchment, where the Mourne River and the Finn River converge at Strabane to form the River Foyle. From Strabane, the Foyle flows north to Londonderry and Lough Foyle. The lough is tidal and exerts a tidal influence up the River Foyle as far as Strabane. The tidal reach of the Foyle, shown in Photograph 16C.1 has a tidal range of approximately 3m and is up to 750m wide in places.

Photograph 16C.1 River Foyle, looking upstream from Drumenny

The main tributaries to the Foyle in the vicinity of the route are discussed in the following sections. However, there are also a substantial number of smaller tributaries which the route crosses. These tributaries are generally large man-made field drains and small streams which have been heavily modified / straightened where they pass through villages and agricultural land as shown in Photograph 16C.2.

Classified as a heavily modified water body by NIEA due to flood defences.

Photograph 16C.2 Left - Typical field drain/modified stream running through agricultural land. Right - Upstream view of the culverted/channelised section of the Blackstone Burn in Magheramason.

Burn Dennet Catchment

The Burn Dennet has a catchment area of approximately 150km2 and rises in the Sperrin Hills, flowing 35km west to the River Foyle. The catchment is predominantly agricultural, although there are significant sand and gravel quarrying sites close to the lower reaches of the river.

The route crosses the Burn Dennet in the vicinity of Burn Dennet Bridge, in this area the river is approximately 15m wide with typical transitional (piedmont) river characteristics i.e. lower gradient, relatively unconfined valley, wider floodplain, riffle/pool sequences and meandering channel pattern (see Photograph 16C.3).

Photograph 16C.3 Burn Dennet Approx 2km Upstream of Burn Dennet Bridge, Looking Upstream

Glenmornan Catchment

The Glenmornan River has a catchment area of approximately 35km2 and rises in the foothills of the Sperrin Hills. From source the river is approximately 16km long and drains westwards to the River Foyle. Although the river rises on peat-covered hills the majority of the catchment is agricultural, with some sand and gravel workings adjacent to the middle reaches of the river. The river, shown in Photograph 16C.4, also passes through Artigarvan and Ballymagorry villages.

Where the route crosses the catchment the river channel is between 4m and 20m wide and displays typical transitional characteristics (as described above for the Burn Dennet).

Photograph 16C.4 Glenmornan River at Ballymagorry, Looking Upstream

Finn Catchment

The Finn River headwaters are in the upland area surrounding Lough Finn in County Donegal, flowing from Lough Finn eastward for 60km to Strabane, where it joins with the Mourne River. The Finn River becomes tidal upstream of Strabane, the Finn has a catchment area of 495km2, upstream of tidal influence.

The route runs along the eastern bank of the lower reaches of the river, which by this point is a mature lowland river, with a wide unconfined valley and floodplain that is relatively deep and slow

Photograph 16C.5 Finn River Immediately Upstream of Strabane, Looking Upstream

Mourne Catchment

The Mourne River forms the middle section of the main spine of the Foyle Catchment and has a catchment area of 1,860km2. The Mourne, shown in Photograph 16C.6, is formed at the confluence of the River Strule and Derg River near Ardstraw. The river flows north to Strabane where it merges with the Finn River to form the River Foyle. The existing A5 crosses the Mourne River in Strabane, where the channel width is approximately 80m.

The Mourne is a transitional river with numerous riffle and pool sequences, which flow in a relatively unconfined valley within a large floodplain. At Sion Mills the river channel and has been heavily modified, where a large weir was historically constructed. As the Mourne River passes through Strabane the channel has been modified by various flood defences.

The route runs parallel with the western bank of the Mourne River.

Photograph 16C.6 Mourne River at Victoria Bridge, Looking Downstream.

Classified as a heavily modified water body by NIEA due to flood defences.

Derg Catchment

The Derg River rises in the Killeter Uplands and flows eastwards to its confluence with the River Strule near Ardstraw. The upper reaches of the catchment are characterised by peatlands, while the lower reaches flow predominantly through farmland. The main stream length of the Derg River is 53km, with a catchment of approximately 440km2

The route crosses the lower reaches of the Derg close to the confluence, see Photograph 16C.7. Within the vicinity of the Proposed Scheme the Derg River is a transitional (piedmont) river characterised by a well developed valley, reasonably large floodplain and variable substrate with riffle and pool sequences.

Photograph 16C.7 Downstream View of Confluence Between Derg River (Foreground) And River Strule.

Strule Catchment

The River Strule forms the upper section of the main spine of the Foyle Catchment, and has a catchment area of 1,340km2. The Strule is formed by the confluence of the Camowen and Drumragh rivers in the centre of Omagh. The Strule flows northwards for approximately 21km before merging with the Derg River to form the Mourne River. The Strule has two major tributaries, the Owenkillew which joins the Strule from the east at Newtownstewart and the Fairy Water which joins to the north of Omagh.

The Strule is a transitional river with variable bed materials, riffle and pool sequences, an unconfined valley and floodplain (Photograph 16C.8). The catchment is predominantly agricultural, although peat bog is present in the upper reaches of the large tributaries and sand and gravel quarrying is present in the Strule valley, particularly north of Newtownstewart.

The entire length of the Strule runs parallel to the route. As the proposed route passes to the west of Newtownstewart the Owenkillew is unlikely to be affected by the Proposed Scheme. The route also crosses numerous small tributaries on the western slopes of the Strule valley.

Photograph 16C.8 Downstream View of the River Strule, Looking Towards Newtownstewart.

Classified as a heavily modified water body by NIEA due to flood defences.

Fairy Water Catchment

The Fairy Water rises on the slopes of Bolaght Mountain in west Tyrone and flows eastwards to its confluence with the River Strule to the north of Omagh. It has a catchment area of 180km2 and a main stream length of 30km. The catchment is predominantly agricultural (grassland pasture), however there are significant areas of peat throughout the catchment, particularly on the valley floor.

The Proposed Scheme crosses the Fairy Water approximately 500m upstream of the confluence with the Strule. In this area the river is approximately 16m wide and has typical transitional characteristics with a meandering channel pattern and riffle and pool sequences, see Photograph 16C.9.

Photograph 16C.9 Upstream from the Fairy Water/Strule Confluence

Drumragh Catchment

The Drumragh River lies in the upper reaches of the Foyle Catchment and is formed to the south of Omagh by the confluence of the Ballynahatty Water and Quiggery Water, as shown on Photograph 16C.10, flowing north through Omagh before merging with the Camowen to become the River Strule. The Drumragh River catchment is approximately 321km2. Due to the nature of the topography in the Drumragh catchment there is an intricate dendritic drainage network, with a large number of tributary streams. Many of the streams have been straightened or otherwise modified, with the exception of the Routing Burn, which is largely unmodified as shown in Photograph 16C.11.

Photograph 16C.10 Drumragh River Downstream of the Ballynahatty-Quiggery Confluence.

Photograph 16C.11 Routing Burn at Barony Bridge.

The route crosses the Drumragh approximately 2.5km downstream of the Ballynahatty-Quiggery confluence. At this point the river is approximately 10-15m wide and has typical transitional characteristics with variable bed material, riffle and pool sequences and an unconfined valley and floodplain.

The route skirts around the eastern extent of the upper Drumragh catchment, crossing a number of small streams / large field drains within the Routing Burn and Eskragh Water sub-catchments.

Camowen Catchment

The Camowen River rises in the hills to the west of Pomeroy and flows westwards to Omagh, where it joins with the Drumragh to form the River Strule. The Camowen River catchment area is approximately 276km2. The Camowen headwaters generally rise in the low-lying peatlands which have formed between the drumlins that characterise this area.

The Proposed Scheme passes through the western extent of the Camowen watershed, crossing the headwaters of a minor tributary to the Camowen River, namely the Ranelly Drain. The reaches that the route pass over range from small semi-natural streams a few metres wide with good flow to very narrow ditches with limited flow as shown in Photograph 16C.12.

Photograph 16C.12 Left - Ranelly Drain 350m Upstream of Confluence with Camowen River. Right - Small Field Drain with Likely Ephemeral Flow.

Classified as a heavily modified water body by NIEA due to drinking water storage features.

Blackwater Catchment

The River Blackwater rises to the west of Fivemiletown and flows eastwards to Aughnacloy, then north-east to Lough Neagh. The Blackwater catchment area is approximately 1,493km2.

The Proposed Scheme crosses the eastern part of the Upper Blackwater catchment, passing through the major tributary sub-catchments of the Roughan Burn and Ballygawley Water, before the Proposed Scheme’s southern boundary on the northern bank of the River Blackwater immediately south of Aughnacloy.

The Roughan Burn rises on the southern slopes of Slievemore and flows south through Ballymackilroy before joining the River Blackwater downstream of Augher. Where the Proposed Route crosses the Roughan Burn, it is a small, shallow stream with gravel and cobble bed, as shown in Photograph 16C.13. Although this reach is generally unmodified, the lower reaches have been extensively straightened.

The Ballygawley Water rises on the slopes of Eshmore Hill approximately 12.5km northeast of Ballygawley. The river flows through the town before joining the river Blackwater at Lismore Bridge, approximately 6km downstream. The Proposed Scheme crosses the Ballygawley Water approximately 2km downstream of the town, at this point the river is approximately 10m wide with a shallow cobble and gravel bed, as shown in Photograph 16C.14.

Photograph 16C.13 Roughan Burn Downstream of Ballynasaggart.

Photograph 16C.14 Ballygawley Water Immediately Downstream of Ballygawley

The remainder of the Proposed Scheme crosses a number of smaller tributaries of the River Blackwater in and around Aughnacloy, namely the Tullyvar, Ravella and Lissadavil. The Tullyvar and Ravella are narrow, shallow, fast flowing, cobble and gravel bedded streams, while the Lissadavil is a narrow, deep, heavily vegetated, sluggish channel that has been heavily modified and meets the Aughnacloy River before flowing south west to the confluence with the Blackwater.

Geomorphologically Sensitive Watercourses

A number of watercourses with Proposed Scheme interactions were identified as being potentially geomorphologically sensitive based on a combination of mapping and aerial photography evidence. These locations were then visited by a geomorphologist who recorded geomorphological features and sensitivities. Further details, methodology and scope of this exercise are provided in Appendix 16F, Fluvial Geomorphology.

Such features may be impacted by the construction and/or operation of the Proposed Scheme or, alternatively, could cause impacts upon the Proposed Scheme during construction and/or operation. The specific watercourses identified are discussed individually below.

Blackstone Burn

The Blackstone Burn flows north west through Magheramason towards its confluence with the River Foyle.

The Blackstone Burn is a 1-1.5m wide channel with 1m high banks which are steep and predominantly well vegetated. The channel has large cobbles and boulders protruding above the surface of low flow conditions. Deposition of material within the channel has led to lateral and point bar development. There is evidence of small-scale bank undercutting and poaching, both of which have exposed the sandy alluvial soil. The channel has incised into the floodplain and sits within an area of hummocky ground. Small sections of the channel have eroded down to the underlying bedrock. There is a mature riparian zone with a dense cover of trees before reaching open pasture.

Photograph 16C.15 A Typical Section of the Blackstone Burn.

Burn Dennet

The Burn Dennet meanders west towards its confluence with the River Foyle approximately 3km downstream from the existing Burndennet Bridge.

The Burn Dennet is a mature, meandering, 10-15m wide, 2-3m deep watercourse. There are no obvious palaeochannels, but the channel is sinuous, which suggests historic channel planform instability. The bed material comprises gravel and cobble and the bank material is composed of cobbles and sand, with sand becoming more dominant higher up the bank. The banks are steep and well vegetated with trees, Japanese Knotweed and Giant Hogweed. There are point bars and evidence of small-scale erosion on some of the banks. There is a large levee on the south side, which is c. 2m high and set back 5m from the channel edge. The crossing will be immediately downstream of a tight meander bend that exhibits historic erosion features on its 7-8m high southern bank. The meandering nature of the channel suggests that erosion of this bend and lateral migration of the channel could continue. Boulders have been placed along the bank as erosion toe protection to defend the adjacent farmland. Within the channel, along the straight where the proposed crossing point is, two small ad-hoc boulder weirs have been created to keep the main thalweg, the fasting moving and most erosive part of the flow, away from the channel banks.

Photograph 16C.16 Looking Upstream at the Crossing Point of Burn Dennet

Glenmornan

The Glenmornan River (also known as Ballymagorry Burn) flows north west through Ballymagorry towards its confluence with the River Foyle, approximately 3km downstream of the existing Ballymagorry Bridge.

Access to the main crossing point was not possible, so the channel was viewed at Ballymagorry. The channel has large levees (1.5-2m) on either side set back 3-4m from the channel edge. The channel has incised 1-1.5m into the floodplain. The channel is 2.5-3m wide with a gravel/cobble bed and a sandy alluvial bank that is well vegetated with grass. The channel is heavily modified with inconsistent stone toe protection along its length. There are lateral bars, indicating that sediment is mobilised, resulting in a concentration of flow, which could lead to bank erosion and meander development. The channel has incised through a flat, low gradient floodplain. The channel has a pool-riffle sequence. At the point of the crossing, the channel is sinuous. Palaeochannels are visible on aerial photographs. The control of lateral movement of the channel has resulted in incision of the bed becoming the dominant erosion process.

Photograph 16C.17 Glenmornan Looking Downstream at Ballymagorry.

Mourne River

The Mourne River flows north west through the town of Strabane towards its confluence with the River Foyle, immediately upstream of the existing Foyle Bridge which is located on the north west side of Strabane.

The Mourne River is a large, 20-30m wide watercourse with low gradient and slow flow within a large floodplain. Upstream of the proposed crossing point, the northern bank of the river has been protected with a flood wall, which terminates immediately after the existing bridge. At this point, the flood wall merges into an old masonry wall, which merges into an earth bank at the point of the proposed crossing. The earth bank is 2m high, and is set back 5m from the channel edge. There is a similarly sized levee on the south side of the river. The 2m high natural channel banks on the north side are steep and grass covered with small areas of erosion evident. The banks on the south side are less steep, grass covered and gradually slope up to the levee, with a point bar composed of sand developing on the inside of the bend. It was not possible to see the bed material on the day of the site visit because of the depth of the water and the high turbidity level. To the north of the river, the area is dominated by local infrastructure. The confluence with the Finn River is only 400 metres downstream. Erosion is evident and likely to continue on the northern banks where some toe protection is already in place.

Photograph 16C. 18. Looking West at the Crossing Point of the Mourne River from the North Bank

UD 15 (Mourne River Tributary)

This tributary (UD_15) drains a small network of field drains and flows east towards its confluence with the Mourne River, immediately downstream of the Seein Bridge.

UD_15 is a 1-1.5m wide, shallow watercourse confined within a narrow valley, with a dense cover of trees. The bed material comprises large cobbles and boulders, which have been transported and deposited recently, and there is evidence of flood deposits on the floodplain adjacent to the watercourse. Land use is dominated by agriculture. This watercourse is geomorphologically sensitive.

Photograph 16C. 19. UD_15 with Large Cobble Bar on Left Indicative of Active Erosion and Deposition.

Derg River

The Derg River flows north east to its confluence with the Mourne River, approximately 300m downstream of New Bridge.

The Derg River is a large 20-40m wide, shallow, natural, boulder bed watercourse. The watercourse is confined between steep, high terraces that are predominantly 10-50m from the watercourse on both sides. However, upstream of the proposed crossing point on the outside of a meander bend the watercourse is actively eroding into the southern terrace, creating a 20m high, steep slope. On the opposite side of the channel there is a flat, wide and open floodplain. A cobble point bar is actively accumulating on the inside of the meander. Within the channel the boulders are moss covered, indicating that large bed material has not been transported recently, however there were deposits of recently deposited cobble sized material. The flow is characterised by pools and riffles interrupted by exposed boulders.

Photograph 16C. 20. Looking Upstream Along the Derg River with Evidence of Recent Deposition of Cobbles in the Foreground.

UD_20 (Coolaghy Burn, Derg River Tributary)

Coolaghy Burn (UD_20) flows generally north west to converge with the Derg River approximately 3km downstream of Coolaghy.

The watercourse is a 2-4m wide, 0.5-1m deep channel incised into a flat floodplain. The channel has low sinuosity and the banks are poached due to the channel marking the boundary of two fields used for grazing. Along the channel edge, trees have become established, which indicate long-term stability of the channel position. However, there is evidence of some bank erosion and remobilisation of large cobbles into the channel, which are deflecting the thalweg towards the channel banks, potentially result in their erosion.

Photograph 16C. 21. UD_20 Cutting Across a Flat Floodplain, With Some Evidence of Cobble Deposition on Left-Hand Bank of the Channel, Looking Downstream.

UD_22 (Mourne River Tributary)

This tributary of the Mourne River (UD 22) flows north through Liby towards its confluence with the Mourne River approximately 500m downstream of Abercom Bridge.

UD_22 is a very small watercourse, with little baseflow, on a steep slope (approximately 10 degree), that has been artificially straightened adjacent to the existing road. The bank material is a sandy till with a high gravel and cobble content. The bed material is predominantly comprised of cobbles and gravel. The watercourse has incised 3-4m into the slope, before turning 90 degrees to the north. Around the outside of this sharp bend there is evidence of bank erosion. The local landowner has attempted to protect the bend and his land from further erosion by placing concrete blocks around the outside of the bend as toe protection. Any increased discharge into this small channel may exacerbate the erosion problem. The land on either side of the channel is agricultural land with a road running parallel to the southern side of the channel. Runoff from the road flows directly into the watercourse via a hand-dug gully and down the channel banks, which has resulted in failure of the channel banks. Bank failure is also evident on the north side of the channel.

Photograph 16C. 22. UD_22 Deeply Incised Small Watercourse.

UD_25-26 (Strule River Tributaries)

These Strule River tributaries UD_25 and UD_26 converge downstream of Beltany Lodge before flowing east towards the confluence with the Strule River approximately 200m downstream from that point.

UD_26 is a small, steep, 0.5-2m wide watercourse that has incised 10-15m into the slope down to bedrock, with a top of bank width of 30-50m. The predominantly bedrock bed and banks have a veneer of gravel and cobbles. The channel is characterised by bedrock steps with a step-pool topography. There is a large 4m high waterfall downstream from the proposed crossing. The channel is well confined within its valley and little lateral movement would be anticipated. Therefore, it should accommodate increased flow, however, there may be an increase in transportation and deposition.

Photograph 16C. 23. UD_25-26 Showing Evidence of Recent Deposition of a Large Volume of Cobble- Sized Material.

UD_33-34 (Strule River Tributaries)

UD_33 and UD_34 flow adjacently east to converge with the Strule River.

Both UD_33 and UD_34 are 1m wide by 0.5-1.5m deep, straight, ephemeral watercourses that have incised into a steep slope. They have formed a step-pool topography within till and there are slugs of cobble to boulder sized material that have been transported during high flows. There is no evidence of lateral movement, so erosion and entrainment of material is from the channel bed during high flows.

Photograph 16C. 24 UD_33-34, Often Ephemeral, but Steep and Straight and Capable of Transporting Cobble-Sized Material.

Fairy Water

The Fairy Water flows generally east towards its confluence with Strule River immediately downstream of Poe Bridge.

The Fairy Water is a 10-15m wide and deep (could not see the bed on the day of the visit) watercourse. Channel banks are up to 2m high and steep on both banks. There are 1.5m high levees on both sides that are set back 5m from the edge of the channel. There is imperceptible flow due to the low gradient cutting across a wide, well vegetated alluvial floodplain. No evidence of erosion or deposition, but meandering suggests past channel change. The flow is smooth. The Fairy Water is geomorphologically insensitive.

Photograph 16C. 26 Fairy Water Channel Showing Evidence of Toe Protection on the Right-Hand Bank.

Routing Burn Extension

The Routing Burn Extension drains several smaller tributaries to the east and flows towards its confluence with Eskragh Water, approximately 1km downstream of Brown’s Bridge.

The Routing Burn Extension is a 3-5m wide bedrock controlled channel. It has incised down to bedrock which has eddie scour holes, suggesting long-term stability of channel position. The watercourse has a step-pool topography, with step height of less than 0.5m and pools varying in size. There is deposition of cobble-sized material within the channel and erosion of material on channel banks and bed in a lower gradient upstream. Bedrock control prevents lateral movement of the watercourse and the low rate of incision. The channel meanders through hummocky terrain on a moderate gradient, with evidence of deposition of material on the inside of meanders. Both banks are well vegetated with trees, shrubs and grasses. Some of the younger trees have been streamlined in a downstream direction by high flows. There is a waterfall and large pool evident in a glacial meltwater channel, with a large mid-channel bar downstream of the pool, confined by bedrock, however, there are large deposits that could be transported downstream.

Photograph 16C. 28 Bedrock-Controlled Routing Burn, Evidence of Deposited Cobble-Sized Material can be seen in the Centre of the Image.

UD_69 (Routing Burn Tributary)

UD_69 is one of several watercourses drained by Routing Burn / Routing Burn Extension, flowing generally west.

This tributary is a very small 0.5-1m wide by 0.5-1m depth watercourse with steep, well vegetated channel banks and a bed comprising sand to cobble-sized material set within a narrow and boggy 30m wide floodplain. The channel is restricted within a narrow floodplain, with limited potential for channel migration between the valley sides. The channel is sinuous within the confines of the floodplain, but is low gradient with very little flow. There is pasture land on both sides, but a tree dominated riparian zone exists. There is little evidence of erosion, bank overtopping or deposition outside of channel, it is therefore considered geomorphologically insensitive.

Photograph 16C. 29 UD_69.

Roughan Burn

The Roughan Burn drains several smaller tributaries to the north of Ballynasaggart and continues to flow generally south, with several convergences with other watercourses, until its confluence with the River Blackwater.

The Roughan Burn is a 2-3m wide, 0.5-1m deep stream that flows through a flat, wide floodplain occupied by arable farming. The channel has migrated to the southern side of the floodplain where it lies against a steep slope. The material within the channel is predominantly gravel, with some cobbles. At the point of the proposed crossing, the channel is straight, but downstream there is evidence of deposition of material in the channel and large boulders have been placed at the toe of the bank to prevent bank erosion.

Photograph 16C. 30 Roughan Burn Looking Downstream Showing the Gravel/Cobble Bed.

Ballygawley Water

The Ballygawley Water flows south from Ballygawley, draining several smaller tributaries en route before converging with Tullyvar downstream of Lismore Bridge, approximately 6km downstream of Ballygawley.

The Ballygawley Water is a 4-7m wide watercourse that has incised into the floodplain. It is currently located on the far western side of its floodplain, where it is actively eroding into the terrace immediately upstream of where the proposed road is to cross. At this bend, ad-hoc bank protection and river training has been installed creating a step-pool feature, with large angular blocks placed at the toe of slope in an attempt to prevent bank erosion. The banks are 3m high on the west side and 2m on the east, which show evidence of instability. There is an old fence line lying on the steep west bank of the river, suggesting rapid erosion of this bank. A lateral bar has developed downstream of the step-pools on the east side, forcing flow to the west. Bed material comprises cobbles and boulders. There is evidence of flood detritus in the trees on the west bank. The land on either side of the river is used for grazing.

Photograph 16C. 31. The Geomorphologically Sensitive Ballygawley Water Showing Evidence of Ad-Hoc Channel Protection in the Form of Rip-Rap and Shallow Step-Pool Sequences.

UD_89 (Ravella Tributary)

This tributary (UD_89) flows southwest to converge with Ravella on the western side of Dernabane which is located approximately 1.5km north west of Aughnacloy.

UD_89 is a small, 1.5-2m wide and 0.5-1m deep watercourse with alluvium sand banks and a gravel/cobble bed. The channel is confined within hummocky terrain with a narrow floodplain (<30m wide). There are large bar deposits suggesting it can be very active and cause lateral movement of the channel.

Photograph 16C. 32. The Confined Floodplain of the Small Historically Active UD_89.

UD_90 (Aughnacloy Urban Extension Tributary)

UD_90 flows south to converge with the Aughnacloy Urban Extension on the northern side of Aughnacloy.

Due to access restrictions this watercourse could not be inspected at the proposed crossing point, however the burn was visited downstream near Aughnacloy Primary School. From the aerial photography it appears the channel is active, based on the frequency of meanders and sharp bends. The channel is < 2m wide and has reasonably steep banks that are well vegetated and a gravel and cobble bed. Increased discharge may cause increased transportation and deposition. A possible palaeochannel has also been identified from the aerial photography, located in the area of flat land immediately upstream of the Proposed Scheme.

Photograph 16C. 33. A Section of the UD_90, 5 km Downstream of Aughnacloy

Lissadavil

Lissadavil flows southwest draining several smaller tributaries and converges with the Aughnacloy River which flows south through the centre of Aughnacloy village.

This is a 1-1.5m wide and 1.5-2m deep channel with very steep banks that have been excavated to stop lateral migration of the channel across a 100m wide floodplain. The channel has incised through alluvial sand with occasional cobbles. Further lateral movement is unlikely due to the depth of channel, but the outside of meander bends could suffer some erosion in high flows. The tops of banks are well vegetated, but bare earth is exposed lower down the channel banks. There is rough grazing on either side with drainage of the floodplain evident on the surface.

Photograph 16C. 34 Artificially Deepened Lisadavil Watercourse

Surface Water Quality Monitoring

A summary of the average water quality measurements collected by NIEA in this general area are presented in Table 16C.2. These surface water monitoring locations are shown on Figure 16.19. Further water quality information, including data from other sources, is provided in Appendix 16G.

Table 16C.2 2004–2013 NIEA Surface Water Quality Monitoring

2004-2013 Average Water Quality Measurements

Surface Watercourse C) 

Grid g/l) 

NIEA Monitoring Reference ) /l g Station Description pH g/l) s/cm)  m ( aturation) ( (mg/l)  ( s Oxygen Oxygen Dissolved Dissolved Biological Suspended Suspended Solids (mg/l) Conductivity Conductivity (% Total Hardness Total Hardness Soluble Copper Soluble Copper Total Zinc ( Oxygen Demand Demand Oxygen Temperature ( Temperature

Burn Dennet 237400E 9.7 266 7.7 1.9 7.0 112 97 5 1.5 F10022 BURNDENNET 404800N RIVER AT BURNDENNET BRIDGE

238400E Glenmornan River 9.3 235 7.6 2.5 10.2 98 94 15 1.7 400500N F10014 GLENMORNAN R AT CATHERINES BR

Finn River 229300E 10.7 136 7.3 1.7 7.9 50 93 7 1.7 394000N F10025 FINN (FOYLE) R AT CLADY BR

Mourne River, Strabane 234500E 10.6 184 7.6 2.0 7.2 73 94 8 1.9 397500N F10028 MOURNE R AT STRABANE BR

Mourne River, Victoria Bridge 235300E 10.1 188 7.7 4.4 10.7 80 94 8 1.9 390700N F10029 MOURNE R AT VICTORIA BR

Coolaghy Burn, Derg River 236400E 10.4 196 7.5 3.5 12.0 73 92 8 1.6 F10042 LOUGH 387500N CATHERINE STREAM AT MILLBROOK

2004-2013 Average Water Quality Measurements

Surface Watercourse C) 

Grid g/l) 

Derg River 236500E 10.4 147 7.3 1.7 7.6 52 93 5 1.8 F10044 DERG RIVER 387700N AT MILLBROOK NEW BRIDGE

River Strule, Newtownstewart 241100E 10.3 252 7.7 2.8 7.9 105 91 11 2.0 F10086 STRULE R AT 386100N MOYLE BR

River Strule, Mountjoy

243700E F10087 STRULE R AT 10.4 257 7.6 3.7 8.0 112 84 10 2.1 STONE BR 377600N

River Strule, Omagh 244900E 10.3 251 7.7 4.1 9.1 110 91 12 2.0 372900N F10088 STRULE R AT ABBEY BR, OMAGH

Fairy Water 242900E 10.1 254 7.5 3.4 8.0 115 84 9 1.9 F10099 FAIRY WATER 374900N AT DISUSED RAILWAY BRIDGE U/S OF NESTLES

Camowen River 246400E 10.1 233 7.7 2.4 10.4 102 92 13 2.0 373000N F10111 CAMOWEN R AT DONNELLYS BR

2004-2013 Average Water Quality Measurements

Surface Watercourse C) 

Grid g/l) 

Drumragh River 245500E 10.2 253 7.7 3.2 11.6 108 90 11 2.1 F10128 DRUMRAGH R 372700N AT CAMPSIE BR

Garvaghy Burn 254100E 9.7 212 7.5 3.3 7.0 92 91 12 1.6 F10126 GARVAGHY 361800N BURN AT KILNAHEERY

Routing Burn 250700E 9.7 223 7.7 2.5 6.5 93 93 11 2.3 361700N F10137 ROUTING BURN AT BROWNS BR

Eskragh Water 251300E 9.4 245 7.4 3.3 7.9 102 84 15 2.5 359700N F10127 ESKRAGH WATER AT ESKRAGH

Roughan Burn, Blackwater 258600E 9.3 314 7.8 3.0 11.8 179 90 11 2.3 F10312 BLACKWATER 354900N R FEEDER AT BALLYGREENAN

Ballygawley Water 263000E 9.7 406 7.9 2.8 9.1 189 88 15 3.6 F10348 353800N BALLYGAWLEY WATER AT LISMORE BR

2004-2013 Average Water Quality Measurements

Surface Watercourse C) 

Grid g/l) 

262500E River Blackwater 10.3 408 7.9 2.7 9.7 197 89 11 1.9 35300N F10333 BLACKWATER R AT DERRYMEEN BR

Surface Water Abstractions

Public and private surface water abstraction data was requested from NIEA for the River Foyle and River Blackwater catchments and all individual WFD surface waterbodies through which the Proposed Scheme passes. These locations are shown on Figures 16.2-16.18 and 16.19.

There are 3 public water abstraction locations, operated by NI Water for drinking water supplies within the catchments crossed by the Proposed Scheme, of which 2 are downstream. These are collecting water from the Mourne River and Camowen River, located 2.5km and 4km downstream, respectively, of Proposed Scheme components.

58 surface water abstraction locations were provided which comprise all licenced abstractions as well as completed applications for abstraction consent in this region, with 18 abstractions located within surface water catchments that the Proposed Scheme crosses. There are 8 private surface water abstractions downstream of the route corridor. These abstractions are associated with quarries, concrete production, power stations (hydro and gas fired), gold extraction, protein processing and fish farming. Of these, 5 are on main watercourse channels, where surface water flows and water quality would be expected to be more reliable and consistent in comparison with smaller channels where more seasonal variability would be anticipated. The remaining 3 are located on smaller, minor watercourses / field drains, with 2 of these abstractions located within 100 m downstream of the Proposed Scheme. These are the supplies associated with Supermix Concrete Ltd, Newtownstewart, and Dalradian Gold Ltd, Omagh.

Abstractions located downstream of the Proposed Scheme corridor are identified in Table 16C.3.

Table 16C.3 NIEA Surface Water Abstractions Downstream of Scheme Corridor

Approximate Local Management WFD Surface Distance Watercourse Easting Northing Area Waterbody Downstream of Route

247980 422251 13.5 km (Private) Foyle and Burn Dennet and Foyle Faughan River Foyle Estuaries 246967 421611 12 km (Private)

238978 386465 2.5 km (Public)

234674 393017 3 km (Private) Derg and Mourne Mourne River Mourne River 238105 387075 4 km (Private)

238935 386575 2.5 km (Private)

Scotts Mill Layde 238279 385693 100 m (Private)

Camowen River Camowen River 247360 371220 4 km (Public)

Strule River Strule UD_32 241800 381240 100 m (Private)

Tributary of Eskragh Water Eskragh 251600 359450 3 km (Private) Extension

Discharges

In Northern Ireland consent is required to discharge any trade or sewage effluent or any other potentially polluting matter (including site drainage liable to contamination) from commercial, industrial or domestic premises to waterways or underground strata. Information on discharges and discharge consents within the vicinity of the proposed route has been provided by NIEA.

Within the route corridor there are discharges from a number of public wastewater treatment works (WwTW), septic tanks, combined sewer overflows (CSO) and wastewater pumping stations (WwPS) owned and operated by NIW. WwTW are generally associated with the larger towns and villages in the area and the treated sewage effluent is continuously discharged directly into the larger rivers, the CSO and WwPS would be anticipated to be more intermittent discharges than

WwTW. The septic tanks typically serve a small cluster of properties, with the partially treated effluent generally discharged to groundwater via a soakaway.

In rural areas where connection to the public sewerage system is not possible, individual properties have private septic tanks. In Northern Ireland as a whole it is estimated that there are approximately 120,000 septic tanks, less than 100,000 of which are consented. As a result there is not a complete register of private septic tanks available and the number within the vicinity of the proposed route is uncertain. However, it is assumed that the majority of rural properties within the vicinity of the Proposed Scheme are served by individual septic tanks. Many private septic tanks are known to function poorly and this, combined with the number of tanks, can lead to issues with diffuse and point source pollution.

A summary of the known discharges, provided by NIEA, within 1 km upstream or downstream of a proposed mainline highway outfall is provided in Table 16C.4. It should be noted that there is likely to be a significant number of additional unidentified private septic tank discharges in the vicinity of the proposed route.

Table 16C.4 Summary of Existing Discharges within 1 km of a Proposed Drainage Outfall

Local Management WFD Surface Receiving Site / Discharge Easting Northing Area Waterbody Watercourse Type

New Buildings WwPS 241127 412973 and CSO

Dunhugh Manor 241346 413343 WwPS

River Foyle Private Sewage: 241390 413440 Emergency Overflow Foyle and New Buildings Faughan 240525 412320 Desmonds WwPS Estuaries Magheramason 239197 410949 Burn Dennet and Foyle WwTW Blackstone Burn

Dunnalong Road 239280 410530 WwPS

Nancy Burn 234328 398648 Park Road CSO

Burn Dennet Burn Dennet 237172 404737 Drummeny WwTW

Local Management WFD Surface Receiving Site / Discharge Easting Northing Area Waterbody Watercourse Type

Ardnafoyle Strabane Park Road Drain 234278 398276 CSO

Ballymagorry Tyrone 236827 401600 WwPS Burn Dennet and Foyle Glenmornan Glenmornan River River Private Sewage: 236850 401810 Unspecified

233538 397259 Lisnafin Park WwPS

233255 397516 Finn View WwPS Finn River Finn River Urney Road Glenfin 232988 397040 WwPS Derg and Mourne Private Sewage: Mourne River UD_12 233320 393930 Unspecified

Derg River 1 Derg 235310 387670 Ardstraw WwTW (Lower)

Food Processing: 243120 374830 Creamery Fairy Water Fairy Water 243473 374731 Beltany Grove CSO

Site Drainage: 243533 372282 Unspecified Fireagh Lough River Strule Strule Drain Site Drainage: 243573 372460 Unspecified

Private Sewage: 248370 367970 Unspecified Camowen Ranelly Drain River Site Drainage: Peat 248100 368100 Bog

Tullybryan Road 262430 356810 WwPS Ballygawley Ballygawley Blackwater 262419 356820 Grange Park WwPS Water River Private Sewage: 261570 355290 Unspecified

Standing Water

There are no major standing water bodies in the vicinity of the Proposed Scheme, however, there are a number of small loughs, ponds and flooded quarries. Further details are provided in Table 16C.5. These waterbodies are shown on Figures 16.1 and 16.2-16.18.

Table 16C.5 Standing Waterbodies in the Vicinity of the Proposed Scheme

Associated WFD Standing Local Management Surface Waterbody Location Description Area Waterbody Name

Derry Road, Large artificial pond, likely fed by Unnamed Strabane culverted stream flowing from the Pond 234670E east, drains into field ditches to the Foyle and 398700N west. Burn Dennet and Faughan Foyle West of Estuaries Strabane,

Unnamed adjacent to Small artificial pond, appears to be Pond River Foyle related to flood defence embankment 234164E 398684N

Strahans

Road, Disused and flooded limestone Strahans Finn River Strabane quarry, likely fed by groundwater and Quarry 233011E direct rainfall 395913N

Located between Small disused reservoir, original use Derg and Mourne Sion Mills Sion Mills unknown, some disused pipework Reservoir and Glebe and chambers apparent, fringes of 233370E reservoir overgrown 393080N Mourne River Small pond identified from aerial 1.2km west of Victoria photography, not visited. No

Unnamed Bridge apparent inflow or outflow, may be fed Pond by field drains and provides drainage 233870E and flood storage for surrounding

390530N agricultural land.

Associated WFD Standing Local Management Surface Waterbody Location Description Area Waterbody Name

500m north Small pond identified from aerial photography, not visited. Appears to of Derg Derg River 1 Urbalreagh River have overgrown and is largely fen. (Lower) Lough Likely groundwater fed with water 236020E levels affected by nearby sand and 388190N gravel workings.

Located on

Coolaghy Small online millpond. From aerial Derg and Mourne Burn, 200m photography appears to be disused, Millbrook south of fringes of pond heavily overgrown. Pond Derg River Sluice structures may pose barrier to

River Derg 236470E fish migration Tributary 387450N (Coolaghy Burn) Small pond identified from aerial Located in photography, not visited. No Upper Deer apparent inflow or outflow, may be fed Park, 1km by field drains and provides drainage south west and flood storage for surrounding Unnamed of agricultural land. May be associated Pond Newtownste with surrounding archaeological wart features. 238890E Located close to other pond in Upper 385310N Deer Park Small pond identified from aerial Located in photography, not visited. No Upper Deer apparent inflow or outflow, may be fed Park, 1km by field drains and provides drainage south west and flood storage for surrounding Unnamed of Mourne River agricultural land. May be associated Pond Newtownste with surrounding archaeological wart features. 238900E Located close to other pond in Upper 385380N Deer Park

Associated WFD Standing Local Management Surface Waterbody Location Description Area Waterbody Name

Located 200m east of Small pond identified from aerial Unnamed Beltany Bog Strule Eskragh Water photography, not visited. Appears to Pond Drain be artificial. 254770E 358488N.

Surface Flow Characteristics

A number of the major rivers in the study area are gauged and records were retrieved from the National River Flow Archive (NRFA) providing information on the flow regime of each. A summary of these statistics are provided in Table 16C.6. Note the Q95 flow is the flow exceeded 95% of the time and is a measure of annual low flows. Similarly the Q10 flow is the flow exceeded 10% of the time and is a measure of annual high flows.

Table 16C.6 River Gauging Station Data.

) NRFA 2 Q95 as Mean Low Station Station % of 3 River Flow Flow Q95 Q10 (m /s) Name and Location Mean (m3/s) (m3/s) ID Flow Area (km Standard Average Station Catchment Catchment Station Annual Rainfall (mm) Rainfall Annual

Burn Dennet 237249E Burn Dennet 148.3 1186 3.95 0.82 21% 8.46 201007 404792N

Drumnabuoy 234779E Mourne House 1843.8 1288 57.87 6.61 11% 141.7 395969N 201010

Castlederg 226513E Derg 335.4 1558 14.365 0.92 6% 35.74 201008 384217N

Dudgeon 240583E Fairy Water Bridge 158.4 1285 5.26 0.42 8% 13.4 375813N 201002

Camowen 246071E Camowen Terrace 276.6 1144 6.87 1.09 16% 15.25 373049N 201005

Campsie 245944E Drumragh Bridge 320 1163 8.27 0.68 8% 21.2 372193N 201006

Derrymeen 262509E Blackwater Bridge 182.9 1142 4.82 0.65 13% 10.76 353031N 203022

The rivers’ Q95 flows in the vicinity of the route can indicate the dilution potential available in the rivers for point drainage outfall discharges. Insufficient flow within the rivers during low flow conditions may result in pollution. With this in mind, Q95 flow estimates have been calculated for all watercourses in the vicinity of the route using LowFlows2 software. A selection of these are provided for information on Table 16C.7, exhibiting the variety of surface water flow characteristics through the Proposed Scheme corridor.

Table 16C.7 Estimated Q95 Flows for Selected Watercourses )

2 Est Est Low Q95 as % Surface Estimate Mean Grid Ref Flow of Mean Watercourse Location Flow 95 Annual Annual 3 Q Flow Average Average Estimate Estimate Standard Standard (m /s) 3 Area (km Catchment Catchment (m /s) Rainfall (mm)

Burn Dennet 237249E Burn Dennet 147.1 1186 3.83 0.77 20% 201007* 404792N

Glenmornan Downstream of 236471E 32.4 1143 0.81 0.13 16% River Ballymagorry 402273N

Adjacent to 232651E Finn River 530.2 1346 18.59 2.17 12% Urney Road** 397020N

Ranelly Drain, North of 248614E 4.1 1067 0.09 0.01 9% Camowen Tullyrush 367170N

East of 252424E Routing Burn Greenmount 19.61 1155 0.47 0.07 15% 361839N Lodge

Head waters of North of 254011E 3.36 1133 0.08 0.01 10% Eskragh Water Beltany Hill 359092N

Roughan Burn, South of 259708E 11.3 1128 0.25 0.03 10% Blackwater Ballynasaggart 356610N

By Old Chapel 265378E Ravella 4.54 985 0.10 0.01 9% Road 353905N

Lisadavil, South of 261918E 45.1 1069 1.05 0.13 12% Blackwater Lisadavil 355795N

Ballygawley 262301E Tullybryan 44.65 1071 1.04 0.13 13% Water 356623N

*River gauging station location catchment boundary downloaded and processed using LowFlows2 and included in Q95 flow estimates to demonstrate level of accuracy expected using this method by comparison with gauging station data in Table 16C.2 (www.ceh.ac.uk/data/nrfa/data/gauging_stations.html)

**Location cited as within tidal section of Finn River by FEH

Flood Risk

There are a number of floodplain areas throughout the Proposed Scheme; particularly notable flood extents are associated with the River Foyle, Fairy Water and Ballygawley Water. An overview of flood risk locations in the Proposed Scheme corridor are provided in Table 16C.8, following an October 2014 review of the online Rivers Agency Flood Maps.

Table 16C.8 Baseline Flood Risk Conditions

Local General Flooding WFD Surface Waterbody Watercourse Management Area Commentary Extensive area of river flooding, Burn Dennet and widening where major tributaries River Foyle Foyle Foyle and Faughan Estuaries the Burn Dennet, Glenmornan River and River Deele converge. Flooding confined to the area immediately adjacent to the main channel across much of its Burn Dennet Burn Dennet course. Areas of widened floodplain are visible at Burn Dennet Bridge, Barley Hill and at confluence with the River Foyle. Extensive floodplain between the Glenmornan Glenmornan River western bank of the Glenmornan River River and River Foyle.

Moderately wide floodplain adjacent to main channel to the Derg and Mourne village of Claudy. Wider Finn River Finn River floodplain areas at confluences with Flushtown and the Mourne River.

Moderately wide floodplain in upper course notably between Sion Mills to south of Strabane. Widened flooding zone confined where confluences with numerous Mourne River Mourne River tributaries, notably at Victoria Bridge and Sion Mills. Floodplain narrows at Strabane before widening at the Finn River confluence.

Local General Flooding WFD Surface Waterbody Watercourse Management Area Commentary Extensive floodplain at Castlederg where several smaller tributaries Derg River converge with the main channel. Floodplain narrows in its lower Derg River (across both WFD stretches, course, widening around including Coolaghy Burn) Spamount and Ardshaw and again at its confluence with the River Strule.

Strule

Floodplain within urban Strule settlements of Omagh and River Strule Newtownstewart. Widening at (across both WFD stretches) confluence with the Owenkillew River.

Strule

Extensive floodplain in much of its Fairy Water Fairy Water lower course and at confluence with the River Strule.

Substantial floodplain in the lower sections, notably at confluence Drumragh with the Camowen within Omagh. Drumragh River River Floodplain is narrower upstream, widening surrounding the Doogary/Dublin Road. Floodplain noted across central and south eastern areas of Omagh. Floodwaters from the Camowen Camowen River Drumragh River also interact with River the Camowen floodplain. Floodplain is narrower in the rural area south of Omagh. Floodplain is predominantly Routing Burn Routing Burn narrow with wider area across the Newtownsaville Rd and at confluence with the Eskragh

Local General Flooding WFD Surface Waterbody Watercourse Management Area Commentary Water.

Eskragh Water Wide floodplain on western bank, Eskragh Water confined to rural area between the (across both WFD stretches) Corkill and Newtownsaville roads The majority of this floodplain is Blackwater Tributary confined immediate to its main Blackwater Roughan Burn (Roughan Burn) channel, with some wider areas south of Glenhoy Road. Mapping shows ‘strategic floodplain’ with wide floodplain areas north of Ballygawley. Narrower floodplain within Ballygawley Ballygawley, with floodplain Ballygawley Water Water generally limited to the area immediately adjacent to the main channel for the majority of its course before confluence with the River Blackwater. Mapping shows substantial areas of ‘strategic floodplain’ inundating the northern areas of Aughnacloy. Blackwater Aughnacloy Downstream of Aughnacloy, Lisadavil (Aughnacloy River) floodplain widens substantially with flood waters potentially interacting with those of the larger River Blackwater. Mapping shows significant areas of ‘strategic floodplain’ inundating much of the surrounding River River Blackwater 5 floodplain south of Aughnacloy. Blackwater Significant flooding shown downstream of its confluence with tributaries, west of Aughnacloy).

More specifically, preliminary flood risk assessments identified a number of floodplains within the study area of the Proposed Scheme and along the alignment of the Preferred Route of the A5 WTC. These were identified using historical flood maps, alluvium mapping, Rivers Agency Flood Maps and other sources; which included data in relation to desktop studies and survey information.

Table 16C.9 details the potential floodplains along the route, following a general north to south sequence.

Table 16C.9 Preliminary Floodplain Identification

Floodplain Identifier Floodplain Mouchel Rivers Watercourse Location Model Historical Alluvium Agency Other Summary Reference Flooding Floodplain Strategic Source Indicated Indicated Flood s Maps Between Magheramason Gortin Hall Drain, Foyle and M.A - - X X Rossnagalliagh at Tully Bridge

Blackstone Burn, Foyle Magheramason M.B - X X X

From Carrick Lee (Finn River), Milltown Bridge (Mourne River), Ballynabreen (Deele River), Swilly Bridge River Foyle, Finn River, (Swilly Burn), Mourne River, Deele Burndennet M.1, M.2 and River, Swilly Burn, X Bridge (Burn M.3 X X X Glenmornan & Dennet) and Burndennet Rivers Ballymagorry Bridge (Glenmornan River) to Lough Foyle at Londonderry/Derr y City

Undesignated (UD_15), Upstream Seein M.D Mourne Bridge - - X X

Between Mourne – Strule Derg River Extension at New M.5 - X X X Bridge and Ardstraw

Between New Bridge Coolaghy Burn, Derg M.E - (Coolaghy) and X X X Woodbrook

South west of Back Burn, Mourne M.F - Newtownstewart - - X

Undesignated (UD_37), North west M.G - - - Strule Mountjoy X

Floodplain Identifier Floodplain Mouchel Rivers Watercourse Location Model Historical Alluvium Agency Other Summary Reference Flooding Floodplain Strategic Source Indicated Indicated Flood s Maps South west Tully Drain, Strule M.H - Mountjoy - X X

Fairy Water, Strule, West Omagh Coneywarren Drain, (Lislimnaghan – M.4 X Aghnamoyle and Tully - X X Mullaghmenagh) Drain Rivers

South west Fireagh Lough Drain, Omagh in vicinity M.I - Strule - - X of A32

From Drumshanly Drumragh River to Crevenagh, M.6 X X X X Omagh

Ranelly Drain, In vicinity of M.L - Camowen River Doogary Rd - X X

In vicinity of Letfern, Eskragh M.M - Moylagh X - X

Undesignated (UD_62), In vicinity of M.N - Eskragh Killadroy X - X

Undesignated (UD_66), In vicinity of M.O - Routing Burn Killadroy X - X

Routing Burn & Routing North of M.P/M.Q - Burn Ext. Newtownsaville X X X

Undesignated South east M.R - (UD_110), Eskragh Newtownsaville - X X

Undesignated (UD_77), In vicinity of M.S - Blackwater Kilgreen X - X

Roughan Burn, In vicinity of M.T - Blackwater Ballynasaggart X - X

Tullybryan, south Ballygawley Water west of M.U X X X X Ballygawley

In vicinity of Tullyvar, Ballygawley M.V - Lisginny Rd X X X

In vicinity of Ravella, Blackwater M.W - Derrycreevy - X X

Floodplain Identifier Floodplain Mouchel Rivers Watercourse Location Model Historical Alluvium Agency Other Summary Reference Flooding Floodplain Strategic Source Indicated Indicated Flood s Maps Undesignated (UD_90), In vicinity of M.X - Aughnacloy River Glack - X X

Lisadavil, Aughnacloy South east M.Y - River Aughnacloy X X X

These locations were then developed into hydraulic models; information pertaining to the development of the hydraulic models mitigation is provided in Flood Risk Assessment Report 2 – Hydraulic Model Build Report.

The predicted existing floodplain extents for the ‘design’ events (1% annual exceedance probability (AEP) for river floodplains and 0.5% AEP for tidal floodplains) associated with the flood models referenced in Table 16C.9 can be seen in Figures 16.1 and 16.2-16.18.

Subsequent assessment of impacts is provided in Flood Risk Assessment Report 3 – Impact and Mitigation Assessment Report and has been summarised in Chapter 16 and Appendix 16E of this report.

Groundwater

The road alignment passes over six WFD groundwater bodies, from north to south:

 Claudy WFD Groundwater Body (Chainage 0-17700m);

 Balleybofey WFD Groundwater Body (Chainage 17700-21600m);

 Gortin WFD Groundwater Body (Chainage 21600-33080m);

 Castlederg WFD Groundwater Body (Chainage 33080-38900m);

 Omagh WFD Groundwater Body (Chainage 38900-77080m);

 Aughnacloy WFD Groundwater Body (Chainage 77080-93150m).

Aquifer Classification

There are various local aquifers within each of the WFD groundwater bodies crossed by the Proposed Scheme, which exhibit large variations in individual characteristics.

The Precambrian strata underlying the northern part of the route corridor is classified as having ‘fracture flow, of limited productivity, Bl(f)’. These aquifers are capable of producing high to moderate yields in places, although their dependence on fracture flow also makes poorer yields possible. There is some potential for regional flow, although local flow is more significant. These strata are capable of providing small domestic or farm supplies and may provide baseflow to local streams and ponds.

The Carboniferous rocks, around Victoria Bridge and Omagh, are dominated by sandstones and have been classified as ‘fracture flow, of moderate productivity, Bm(f)’. This indicates that these strata have the possibility of higher yields than the Precambrian bedrock, although the predominance of fracture flow also indicates that low yields are possible.

South of the Omagh Thrust Fault, the bedrock is composed principally of Carboniferous and Devonian sandstones and mudstones. These have been assigned an aquifer classification of ‘fracture flow, of moderate productivity, Bm(f)’. These strata are dominated by fracture flow, but also have some possibility of porous flow although yields are still likely to be variable.

The southernmost part of the route is underlain by limestones, sandstones and mudstones which have a classification of ‘fracture flow, of moderate productivity, Bm(f)’. Fracture flow is dominant and water yields are dependent on the presence and connectivity of fractures.

A number of superficial aquifer deposits are recognised within the route corridor. These are typically glacial sands and gravels and granular alluvial deposits, and are generally associated with the major watercourses along the route, such as the Foyle and Strule. These alluvial deposits are classified as superficial aquifers supporting intergranular flow.

Additional superficial deposits, classified as non-aquifers, are present along the route corridor. These include cohesive and granular glacial till, moraine and peat deposits. Some areas of alluvium are composed of organic clay or more cohesive deposits, giving them a much lower permeability than the granular alluvium and meaning they are considered to be non-aquifers. Some areas have been identified where superficial deposits are thin or absent.

Groundwater Vulnerability

Groundwater vulnerability for Northern Ireland is classified on a five-point scale from 1 (Low) to 5 (Very High). Groundwater vulnerability along the A5WTC has been classified as varying between Class 5 (Very High) and Class 2 (Low).

Generally, the northern part of the route, from New Buildings to Mountjoy, is dominantly classified as 4 (High). There are small areas of Class 5 (Very High), associated with areas of exposed crystalline bedrock. Areas of Class 2 (Low) are associated with 3-10m thick low permeability lake alluvium and glacial till near Strabane and Sion Mills.

Between New Buildings and Sion Mills the Proposed Scheme corridor is almost exclusively underlain by Class 4 (High) vulnerability aquifers. This reflects the high water table within areas of high permeability alluvium within the Foyle floodplain and the sand and gravel deposits of the Burn Dennet and Glenmornan Valleys. There are small pockets of Class 2 (Low) vulnerability associated with low permeability peat deposits and lacustrine deposits with high clay content.

Vulnerability remains generally Class 4 (High) between Sion Mills and Omagh, by virtue of the combination of alluvium and glaciofluvial sands and gravels with a high water table within the Mourne and Strule Valleys and the sandy nature of the glacial till elsewhere within the area. Localised areas of Class 2 (Low) vulnerability are found in the vicinity of Victoria Bridge and between Mountjoy and Omagh, where there are glacial tills of low permeability and areas of peat.

Generally, the southern half of the route is dominated by groundwater vulnerability class 2 (Low) but classes 4 and 5 (High and Very High) are found locally where superficial aquifers are present. The sections between Mountjoy and Gortaclare, and from Ballygawley to Aughnacloy, are dominated by vulnerability class 2 (Low). This is largely a result of the extensive low permeability superficial deposits, mostly glacial tills, moraine deposits or peat. Areas with high permeability superficial deposits have been assigned class 4 (High) to reflect this and consist largely of river alluvium and glaciofluvial sands and gravels.

Between Gortaclare and Ballygawley, the route crosses a region of relatively low permeability deposits, mainly glacial till material, giving a vulnerability class of 2 (Low). This is dissected by areas of high permeability deposits and exposed bedrock, leading to increased vulnerability classifications of 4 (High) or 5 (Very High) for these sections. This corresponds to areas with only thin soil cover or exposed bedrock with dominantly fracture flow.

Within the Clogher Valley, vulnerability varies within the drumlin fields from Class 2 (Low) where there is low permeability glacial till up to 10m thick, to Class 4 (High) in inter-drumlin areas, where soils are thin and alluvial deposits occur, to Class 5 (Very High) in areas of exposed bedrock.

Groundwater Quality

The groundwater bodies throughout the study area have been assessed under the WFD as ‘Good’ for both chemical status and quantitative status. This was partly based on water quality monitoring at a small number of sites within the region. Due to the highly localised nature of the groundwater aquifer systems in the corridor the groundwater quality is expected to vary for specific areas.

Groundwater quality monitoring for a wide range of potential groundwater pollutants has been undertaken by the NIEA for several years. Water test results for 8 monitoring locations in proximity

to the Proposed Scheme have been screened against drinking water standards. The groundwater monitoring locations are shown on Figure 16.20. Where samples failed to meet standard values, these are shown on Table 16C.10, note that pH failures were all due to pH results less than 6.5. The grid reference of each NIEA groundwater sampling location is listed below:

 G277 and N277 at 237888, 408942 (Claudy WFD Groundwater Body);

 G278 at 237871, 406024 (Claudy WFD Groundwater Body);

 G149 at 242997, 374868 (Omagh WFD Groundwater Body);

 G401 at 242630,376016 (Omagh WFD Groundwater Body);

 G72 and GBNIGWNB23-C at 263009, 355551 (Aughnacloy WFD Groundwater Body);

 GBNIGWNB51-C at 262986, 355535 (Aughnacloy WFD Groundwater Body).

Table 16C.10 NIEA Groundwater Monitoring Data – Failures of Drinking Water Standards

Number of Failures

Claudy Omagh Aughnacloy

NIEA Sample NIEA Sample NIEA Sample ID ID ID (Sample ID) Determinant Maximum Exceedance Maximum Exceedance G72 G72 Total Number of Failures of Failures Total Number 23-C 51-C N277 G277 G277 G278 G149 G401 GBNIGWNB GBNIGWNB

pH 6 15 1 1 23 (out of pH 6.1 139 (G278) samples)

Total Organic 1 1 2 (out of 66 3.15mg/l Carbon samples) (G72)

Iron 13 13 (out of 484µg/l 66 (G149) samples)

Manganese 16 16 (out of 262µg/l 66 (G149) samples)

Nitrate 11 11 (out of 382mg/l 66 (G278) samples)

Total 2 2 1 1 6 (out of 38 300cfu Coliforms samples) (G72)

The screening results show only a small number or localised exceedances mainly for iron, manganese, nitrate or total coliforms (bacteria).

Baseline data for well and springs was collected during four monitoring rounds of the Private Abstractions Survey undertaken in 2012. The survey covered wells and springs to be decommissioned, replaced or within a 150 m buffer zone of the vesting line in the northern and southern sections of the Proposed Scheme.

The wells and spring monitoring undertaken in 2012 indicated the existence of contamination related to farming activities. One quarter of the tested wells or springs had bacteria counts exceeding the drinking water standards. Ammonium concentrations above drinking water standard were recorded in 6 out of 44 tested locations and nitrate in 2 out of 44 locations. Other than the aforementioned results, the quality of the other tested locations was found to be generally good.

Groundwater Abstractions

Based on information from the NIEA, there are no public groundwater abstractions in the vicinity of the route, the closest being 1.2km away. This intervening distance is considered unlikely to lead to any Proposed Scheme interaction and public groundwater supplies are not considered further.

Private groundwater abstractions in the vicinity of the route are shown on Figures 16.2-16.18 and are based on the results of the abstractions survey combined with updated historical information from the desk study. The original number of supplies identified was 219, with 47 locations removed from further consideration due to intervening distance relative to the Proposed Scheme and specific local characteristics. The remaining 172 supplies are shown on Table 16C.11, of which 103 are considered actively in use from information provided.

Table 16C.11 Local Groundwater Private Water Supplies, from Private Water Supply Abstractions Survey

Number of Wells or Springs Within Proposed Scheme WFD Groundwater Body Corridor at Risk of Impact

Claudy 21 (13 in use)

Ballybofey 6 (2 in use)

Gortin 26 (17 in use)

Castlederg 7 (6 in use)

Omagh 73 (40 in use)

Number of Wells or Springs Within Proposed Scheme WFD Groundwater Body Corridor at Risk of Impact

Aughnacloy 39 (25 in use)

Total 172 (103 in use)

Peatland

Peat is a soft to very soft, highly compressible organic material that can consist of up to 90% water. It forms in waterlogged conditions where dead organic material, mainly plants undergoes slow anaerobic decomposition, resulting in accumulation of peat over thousands of years. Peat is generally acidic and nutrient poor and as a consequence supports a range of rare and unique plants and wildlife. For this reason peatlands are recognised as areas of significant ecological importance. The peatlands within the route corridor can generally be divided into two categories: raised bog or blanket bog.

Raised bogs are found in lowland areas such as river valleys, lake basins and between drumlins. The peat that forms in these hollows is initially fed by surface water runoff and groundwater, however over time the peat accumulates to form a raised dome and is cut off from both groundwater and surface runoff. The only source of nutrients for the plants on a raised bog is from direct rainfall and the atmosphere. Although the surface of the bog is raised the peat remains waterlogged due to the impermeability of the peat, which results in water being ‘locked’ into the peat body. Raised bogs can have peat up to 12m deep.

Blanket bog generally forms in upland areas with heavy rainfall, low temperatures and underlain by impermeable geology and/or mineral soils that form an iron pan which impedes drainage. These wet conditions allow peat to form and cover extensive areas like a blanket. Due to the undulating nature of the ground the thickness of peat can vary between 1m and 6m.

Both types of peatland habitat are dependent on the waterlogged conditions they form in and are highly sensitive to changes in water level, be this from natural climatic fluctuation or from disturbance of the peat body.

The areas of peatland within the route corridor have been identified from superficial geological mapping and from ground investigation logs; these are summarised in Chapter 12 of the Environmental Statement. Table 16C.12 provides a summary of the main peatland sites and other locations where the proposed alignment intersects or passes within close proximity.

There are two designated peatland sites within the vicinity of the proposed alignment. McKeans Moss (ASSI), 1km south-west of Cloghcor is the most north-western example of lowland raised bog in Northern Ireland. Tully Bog (SAC and ASSI), 2.5km south of Mountjoy is an isolated lowland raised bog lying in a shallow hollow within the former floodplain of the Fairy Water River. These designated peatland locations are shown on Figure 16.1, Figure 16.4 (McKeans Moss ASSI) and Figures 16.10-16.11 (Tully Bog SAC and ASSI).

Table 16C.12 Locations Where the Proposed Scheme Potentially Interacts with Peatland

Highway Peat Grid s Depth Comment Ref Chainag from GI

e Chainage (m) Length (m) Importance Importance

Alignment passes adjacent to McKeans Moss ASSI boundary. Minimum distance between ASSI boundary 236470E 11200 - Very and alignment is 80m. ASSI is a raised peat bog, therefore runoff radiates away from the bog. ASSI also n/a n/a 403150N 12500 High surrounded by deep ditches, which separate the site and the alignment hydrologically. Ground investigation in the area found no peat underlying the alignment.

Small isolated pocket of peat formed in localised hollow. Identified from geological mapping, no ground 233980E 30450 - 140 unknown Low investigation carried out within the mapped peat deposit, however no peat was found at the in GI locations 390610N 30600 immediately outside this area.

234629E 31480 - Small peat deposit up to 1.8m deep within stream valley crossed by alignment, peat immediately adjacent to 80 1.8 Low 389861N 31560 stream, marshy ground upstream.

241702E 45600 - Alignment crosses very edge of mapped peat deposit in inter drumlin hollow/dry channel. The peat is crossed 90 up to 3m Low 379062N 45700 at watershed saddle, therefore minimal impact on peat flows and likely minimised peat depths.

241534E 46400 - Alignment crosses inter drumlin hollow/ stream valley on embankment, peat deposit likely to extend 100m 45 8 Low 378310N 46500 west of alignment, drained by minor field drains. 241766E 47300 10 0.7 Low Very localised peat deposit within stream valley 377463N 241814E 47450 30 0.5 Low Very localised peat deposit within stream valley 377358N Alignment cuts across the edge of extensive inter drumlin peat deposit. Alignment follows lower slope of 242141E 48050 - 440 2.7 Medium drumlin where peat thins out. Therefore the depth of peat crossed is minimised and minimal runoff into peat 376563N 48500 area intercepted. 242685E 49400 - Alignment passes through inter drumlin area, peat depth highly variable, GI results show peat deposit not as 230 3.5 Low 375472N 49650 extensive as geological mapping suggests.

Highway Peat Grid s Depth Comment Ref Chainag from GI

e Chainage (m) Length (m) Importance Importance

Alignment passes adjacent to Tully Bog SAC. Minimum distance between SAC boundary and Proposed Scheme is 60m, where an existing road is proposed to be upgraded to link onto the new carriageway, with 242011E 49600 - Very minimum separation from the new A5 carriageway of 200m. Tully Bog SAC is a raised bog, therefore runoff n/a n/a 375635N 49900 High radiates away from SAC site, which is also surrounded by perimeter ditches. There is an existing natural clay ridge located east of Tully Bog SAC which is likely to act a groundwater barrier. GI in the area shows no continuity between SAC site and peat deposits underlying alignment in this area. 242650E 50400 - Isolated deposit of peat on the upper edge of the Fairy Water floodplain, GI and aerial photo interpretation 180 up to 1.2 Low 374508N 50600 suggests peat deposit is limited in extent, alignment cuts edge of deposit. 242556E 50900 - Peat deposit within stream valley, peat depth variable, likely connected to peat deposit mapped on geological 170 1 Low 374020N 51000 map to NW, this area is drained by multiple field drains. Peat deposit located in low lying inter drumlin area. GI logs indicate peat deposit is more extensive than 242714E 51350 - 585 up to 1 Low shown on geological mapping. Alignment skirts around edge of low lying area, avoiding the main peat body 373426N 51900 and minimising fragmentation of peat deposit. 242769E 52270 10 1 Low Isolated pocket of peat located on small plateau area, GI indicates not extensive deposit. 372796N Based on geological mapping a ribbon of peat winds through inter drumlin area, alignment broadly follows 242939E 52600 - 720 2.4 Low same route, most GI in the area is outwith the mapped peat deposit, therefore true extent of peat difficult to 372161N 53300 discern 243733E 54300 10 2.5 Low Localised peat deposit within stream valley 371067N 244297E Localised peat deposit in inter drumlin area, alignment crosses at saddle therefore minimising depth of peat 55000 47 0.9 Low 370623N crossed 244434E Peat deposit in inter drumlin area, nearby GI results suggest peat is localised, alignment runs parallel to likely 55200 60 0.5 Low 370516N water flow in peat, therefore limited disruption to GW flow within peat 244538E 55370 30 1.1 Low Alignment intercepts edge of peat deposit on lower slopes of drumlin, very localised 370372N

Highway Peat Grid s Depth Comment Ref Chainag from GI

e Chainage (m) Length (m) Importance Importance

244662E Inter drumlin peat, alignment cuts across peat disrupting drainage from east to west. Eastern side of 55380 13 3.1 Low 370284N alignment may become more boggy, PED may drain eastern peat area 244922E 55980 - Peat deposit in stream valley mapped on geological map, no GI carried out in this area, aerial photos suggest 103 unknown Low 369837N 56080 boggy ground 247104E 62100 - Alignment cuts through large area of inter drumlin peat, variable in depth but up to 8m recorded in places. 700 up to 8 Low 369152N 62800 Western end of alignment crosses edge of raised bog, 247977E 63200 - Alignment cuts edge of extensive inter drumlin raised peat bog, alignment minimises excavation of peat, 910 up to 10.5 High 368359N 64100 minimal runoff intercepted, drainage of peat 254228E 74600 - Alignment cuts edge of large inter drumlin peat deposit, alignment skirts lower slopes of drumlin minimising 980 7.2 Low 359059N 75570 peat excavation and runoff interception 256841E 78400 - 40 2.8 Low Isolated pocket of peat in shallow gulley crossed by alignment 357175N 78450 259390E 81000 - 60 1.4 Low Small pocket of peat where alignment crosses head of floodplain area 356649N 81100

Assigning Importance to Water Environment Attributes

The various water environment attributes discussed in the baseline have been evaluated using the attribute importance criteria outlined in Appendix 16B, with the importance assigned to each surface water, flood risk and groundwater attribute provided in Table 16C.13 and Table 16C.14, respectively.

This is a key step in the impact assessment procedure as it establishes the baseline importance of various water environment attributes, to subsequently assess Proposed Scheme interactions.

In relation to surface water, a combination of WFD catchment data and local channel information has been applied, water quality and biodiversity are considered as catchment-wide attributes using the available regional data. Water resources, hydrology and channel geomorphology attributes apply more detailed characteristics available for locations with Proposed Scheme interactions within each catchment, taking account of typical typology of channels. Surface water attributes include the small number of standing water features within catchment areas.

Flood risk importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information), using the most conservative importance rating for those WFD surface waterbody catchments where various floodplains were assessed.

Note that where potential has been identified for surface water abstractions to provide public water supplies, such waterbodies have been assigned an escalated importance value reflecting current and potential future requirements.

In relation to groundwater, groundwater WFD information has been applied and baseline private water supply, river base flow and groundwater dependent location data has been applied.

The River Foyle and Tributaries SAC and River Finn SAC surface water quality are considered as very high importance attributes.

Table 16C.13 Importance of Surface Water Environment Attributes Feature Attribute Comment Importance WFD Overall Status – Moderate Ecological Potential Water Quality & Species - Atlantic salmon, river/brook lamprey Very High Biodiversity River Foyle and Tributaries SAC and ASSI is upstream 2 private water supplies (12km and 13.5km downstream), Surface Water numerous NIW and private domestic wastewater discharges Medium Resources within 1km. Foyle and The River Foyle is a major channel with numerous tributaries of Faughan varying scale, draining a combined 2,905km2 cross-border Estuaries catchment. The Foyle has a tidal influence downstream from Strabane, Burn Dennet where it is formed from the confluence of Mourne River and Finn Flood Risk High and Foyle River.

LMA Flood risk identified through project-specific flood model and the importance has been identified using the overall Foyle River Surface Water System floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). Classified as a heavily modified waterbody due to flood defences. Fluvial Proposed Scheme interactions are predominantly with minor Low Geomorphology tributaries, rather than directly with the River Foyle, these are small channels, often artificially modified or field drains. Water Quality & WFD Overall Status - Moderate High Biodiversity Species – Atlantic salmon, river/brook lamprey, otter

Surface Water Large watercourse with potential for public supply abstraction, High Burn Dennet Resources two NIW domestic wastewater discharges within 1km

2 Burn Dennet One of the main tributaries of River Foyle, draining 150km subcatchment to the east of the Foyle. and Foyle LMA Flood Risk Flood risk identified through project-specific flood model and the High importance has been identified using the overall Foyle River Surface Water System floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). Proposed Scheme interactions are directly with the Burn Dennet Fluvial channel, with evidence of erosion and historic channel High Geomorphology movement, artificial erosion protection evident.

Water Quality & WFD Overall Status – Good High Biodiversity Species – Atlantic salmon, otter One NIW and one private domestic wastewater discharge within 1km. McKeans Moss ASSI is located within the Glenmornan Surface Water catchment, with minimum separation of 80m from the Proposed Medium Glenmornan Resources River Scheme. This is a raised bog with runoff radiating off to surrounding land and is surrounded by deep ditches, resulting in Burn Dennet negligible hydrological linkage with Proposed Scheme. 2 and Foyle Tributary of River Foyle, draining 36km subcatchment to the east of the Foyle. LMA Flood Risk Flood risk identified through project-specific flood model and the High Surface Water importance has been identified using the overall Foyle River System floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). The Proposed Scheme interacts directly with the Glenmornan River, with good quality pool and riffle sequences, mobilised Fluvial sediment, evidence of historic channel movement, artificial High Geomorphology erosion protection evident. There are also a number of interactions with field drain tributaries.

Feature Attribute Comment Importance

River Foyle and Tributaries SAC and ASSI Water Quality & WFD Overall Status - Poor Very High Biodiversity Species – Atlantic salmon

Surface Water Large watercourse with potential for public supply abstraction, Finn River High Resources three NIW domestic wastewater discharges within 1km. Derg and One of the main tributaries of River Foyle, draining 495km2 Mourne LMA subcatchment to the west of the Foyle (cross-border). Lower

reaches of the Finn River are tidal. Surface Water Flood Risk Flood risk identified through project-specific flood model and the High importance has been identified using the overall Foyle River System floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). The Proposed Scheme interacts directly with the Finn River, Fluvial which has little evidence of current geomorphological processes. Low Geomorphology Also interactions with field drain tributaries.

River Foyle and Tributaries SAC and ASSI Water Quality & WFD Overall Status – Moderate Ecological Potential Very High Biodiversity Species – Atlantic salmon, otter

Public water supply abstraction (2.5 km downstream of Surface Water Proposed Scheme), four private abstractions (100m, 2.5km, 3km Very High Resources and 4km downstream of Proposed Scheme), one private Mourne River domestic wastewater discharge within 1km. One of the main tributaries of River Foyle, draining 1,852km2 Derg and subcatchment to the south of the Foyle. Tributaries include the Mourne LMA River Strule and Derg River.

Surface Water Flood Risk Flood risk identified through project-specific flood model and the High importance has been identified using the overall Foyle River System floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). Classified as a heavily modified waterbody due to flood defences. Fluvial Predominantly the Proposed Scheme interactions are with minor Medium Geomorphology tributaries including field drains, also some direct interaction with the Mourne River, with small areas of erosion evident and artificial erosion protection in place. River Foyle and Tributaries SAC and ASSI Water Quality & WFD Overall Status – Moderate Very High Biodiversity Species – Atlantic salmon, otter

Surface Water Public water supply abstraction (4 km upstream of Proposed Very High Resources Scheme), one NIW domestic wastewater discharge within 1km. Derg River One of the main tributaries of Mourne River, draining 436km2 Derg and subcatchment to the south west of the Mourne. Mourne LMA Flood Risk Flood risk identified through project-specific flood model and the Low Surface Water importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information).

Direct Proposed Scheme interaction with the Derg River, with Fluvial erosion evident, bed material transport and pool and riffle High Geomorphology features. Also Proposed Scheme interaction with a main tributary. River Strule Water Quality & WFD Overall Status – Moderate / Moderate Ecological Potential Medium (across both Biodiversity

Feature Attribute Comment Importance stretches) Large watercourse with potential for public supply abstraction, Surface Water one private surface water abstraction (100m downstream of High Strule LMA Resources Proposed Scheme), two unspecified discharges within 1km.

Surface Water One of the main tributaries of Mourne River, draining 1,334km2 subcatchment to the south east of the Mourne.

Flood Risk Flood risk identified through project-specific flood model and the High importance has been identified using the overall Omagh floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). Proposed Scheme interactions are entirely with a large number of minor tributary channels to the west of the River Strule, no Fluvial direct interaction with the River Strule. Tributaries are typically Low Geomorphology very small artificially modified channels or field drains. One of the WFD stretches is classified as heavily modified due to flood defences. WFD Overall Status – Moderate Water Quality & Tully Bog SAC ASSI is located with a minimum separation of High Biodiversity 60m from the Proposed Scheme. No abstractions, potential for public abstraction, one NIW domestic wastewater discharge, one food processor discharge within 1km. Surface Water Tully Bog SAC ASSI is drained by an upstream tributary of the High Resources Fairy Water. This is a raised bog with runoff radiating off to Fairy Water surrounding land and is surrounded by ditches, resulting in

negligible hydrological linkage with Proposed Scheme. Strule LMA 2 One of the main tributaries of River Strule, draining 178km subcatchment to the south west of the Strule. Surface Water

Surface Water No abstractions, no discharges within 1km Low Resources One of the main tributaries of River Strule, draining 323km2 Drumragh subcatchment to the south of the Strule. Main tributaries of the River Drumragh are the Owenreagh and Quiggery Water. River Strule is formed at the confluence of the Drumragh River and Strule LMA Flood Risk Camowen River. Low

Surface Water Flood risk identified through project-specific flood model and the importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). Predominant Proposed Scheme interaction will be on minor Fluvial tributaries, these are artificially modified channels and field Low Geomorphology drains. Direct interaction with the Drumragh River but not geomorphologically sensitive.

Camowen Water Quality & WFD Overall Status – Moderate Ecological Potential High River Biodiversity Species – Atlantic salmon

Feature Attribute Comment Importance

Public water supply abstraction (4 km downstream of Proposed Strule LMA Surface Water Scheme), one private domestic wastewater discharge, one peat Very High Resources bog drainage discharge within 1km. Surface Water One of the main tributaries of River Strule, draining 276km2 subcatchment to the south east of the Strule. River Strule is formed at the confluence of the Drumragh River and Camowen River. Flood Risk Low Flood risk identified through project-specific flood model and the importance has been identified using the overall Omagh floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information).

Classified as a heavily modified waterbody due to drinking water storage. Fluvial Proposed Scheme interactions are entirely with a large number Low Geomorphology of minor tributary channels to the south of the Camowen River, no direct interaction with the Camowen River. Tributaries are typically very small artificially modified channels or field drains.

Water Quality & WFD Overall Status – Moderate High Biodiversity Species – Atlantic salmon

Surface Water No abstractions, no discharges within 1km. Low Resources Tributary of the Eskragh Water, draining 33km2 subcatchment to Routing Burn the east of the Eskragh.

Strule LMA Flood Risk Flood risk identified through project-specific flood model and the Low importance has been identified using the floodplain within the Surface Water model extents associated with the A5WTC (see Flood Risk Assessment for further information). Predominant Proposed Scheme interaction will be on minor tributaries, these are artificially modified channels and field Fluvial drains. Direct interaction with Routing Burn, a small meandering Medium Geomorphology channel with evidence of long term channel position, although current erosion and deposition processes evident.

Water Quality & WFD Overall Status – Moderate / Poor Medium Biodiversity

Surface Water One private surface abstraction (3km downstream of Proposed Medium Resources Scheme), no discharges within 1km. Eskragh Tributary of the Drumragh River, draining 18km2 subcatchment Water to the south east of the Drumragh. (across both stretches) Flood risk identified through project-specific flood models for Flood Risk associated watercourses within WFD catchment and the Low Strule LMA importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Surface Water Assessment for further information).

Proposed Scheme interactions are entirely with a large number Fluvial of minor tributary channels, no direct interaction with the Low Geomorphology Eskragh Water. Tributaries are typically small and many are artificially modified channels or field drains.

Blackwater Water Quality & WFD Overall Status – Poor Tributary High Biodiversity Species – Atlantic salmon, otter

Feature Attribute Comment Importance Blackwater Surface Water No abstractions, no discharges within 1km. Low LMA Resources

Surface Water Tributary of the Blackwater River, known as Roughan Burn or Roughan River, draining 27km2 subcatchment to the north of the Blackwater.

Flood Risk Flood risk identified through project-specific flood model and the High importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information).

Predominant Proposed Scheme influence will be on minor tributaries, these are artificially modified channels and field Fluvial drains. Direct interaction with Roughan Burn, a modified Medium Geomorphology watercourse, with some evidence of deposition and artificial erosion protection.

Water Quality & WFD Overall Status – Poor High Biodiversity Species – Atlantic salmon, otter Surface Water No abstractions, two NIW domestic wastewater discharges, one Medium Resources private domestic wastewater discharge within 1km.

Ballygawley Tributary of the Blackwater River, draining 53km2 subcatchment Water to the north of the Blackwater.

Flood Risk Flood risk identified through project-specific flood model and the High Blackwater importance has been identified using the overall Ballygawley LMA floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information). Surface Water Predominant Proposed Scheme influence will be on minor tributaries, these are a mixture of modified and natural channels. Fluvial Direct interaction with Ballygawley Water, with evidence of bank High Geomorphology instability and very active erosion and deposition. Artificial erosion protection has been installed.

Water Quality & WFD Overall Status – Moderate High Biodiversity Species – Atlantic salmon

Surface Water Large watercourse with potential for public supply abstraction, High Resources no discharges within 1km.

River Major watercourse, draining 1,487km2 and discharging in Lough Blackwater Neagh. (5) Flood risk identified through project-specific flood models for Flood Risk Low Blackwater associated watercourses within WFD catchment and the LMA importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Surface Water Assessment for further information). Predominant Proposed Scheme interaction will be on minor tributaries, these are a mixture of modified and natural channels, Fluvial some of which have geomorphological sensitivities identified. Medium Geomorphology Little direct interaction with River Blackwater, which is not geomorphologically sensitive.

Blackwater Water Quality & WFD Overall Status – Poor Low Aughnacloy Biodiversity

Blackwater Surface Water No abstractions, no discharges within 1km. Low LMA Resources

Feature Attribute Comment Importance

Aughnacloy River watercourse including Lisadavil, draining Surface Water 15km2 area, tributary of River Blackwater.

Flood risk identified through project-specific flood models for Flood Risk associated watercourses within WFD catchment and the Low importance has been identified using the floodplain within the model extents associated with the A5WTC (see Flood Risk Assessment for further information).

Proposed Scheme interactions are entirely with a large number Fluvial of minor tributary channels, a mixture of modified and natural Medium Geomorphology channels, some of which have geomorphological sensitivities identified.

Table 16C.14 Importance of Groundwater Environment Attributes Feature Attribute Comment Importance WFD Groundwater Status - Good Generally high groundwater vulnerability Water Quality High McKeans Moss ASSI is located in this area, minimum 80m Claudy separation from the Proposed Scheme. 21 wells or springs close to the Proposed Scheme, 13 of which Groundwater are in use.

McKeans Moss is a raised bog, this is a rainwater-fed Groundwater (ombrotrophic) and hydrologically isolated site, hence High Resources negligible groundwater linkage with Proposed Scheme.

Relatively large base flow to rivers from groundwater (Burn Dennet and Glenmornan River). WFD Groundwater Status - Good Water Quality High Ballybofey Generally high groundwater vulnerability

Groundwater Groundwater 6 wells or springs close to the Proposed Scheme, 2 of which Medium Resources are in use.

WFD Groundwater Status - Good Water Quality High Gortin Generally high groundwater vulnerability

Groundwater 26 wells or springs close to the Proposed Scheme, 17 of which Groundwater High Resources are in use. WFD Groundwater Status - Good Water Quality High Castlederg Generally high groundwater vulnerability

Groundwater 7 wells or springs close to the Proposed Scheme, 6 of which Groundwater Medium Resources are in use. WFD Groundwater Status – Good Low groundwater vulnerability generally, high vulnerability at locations with shallow soil coverage and river alluvium.

Water Quality Tully Bog SAC ASSI is located in this area, with a minimum High 60m separation from the Proposed Scheme, where there is a proposed alteration to an existing side road, existing natural Omagh clay ridge acting as a barrier for groundwater movement between the Proposed Scheme and Tully Bog SAC. Groundwater 73 wells or springs close to the Proposed Scheme, 40 of which are in use.

Groundwater Tully Bog SAC ASSI is a raised bog, this is a rainwater-fed High Resources (ombrotrophic) and hydrologically isolated site, hence negligible groundwater linkage with Proposed Scheme. Relatively large base flow to rivers from groundwater (Routing Burn). WFD Groundwater Status - Good Aughnacloy Water Quality Low groundwater vulnerability generally, high vulnerability at High locations with shallow soil coverage and river alluvium. Groundwater Groundwater 39 wells or springs close to the Proposed Scheme, 25 of which High Resources are in use.