17    CONSTRUCTION IMPACTS

17.1  Introduction and Methodology

This chapter assesses potential impacts during the construction of the road. The assessment has been based upon available construction information for each route. Construction impacts on Surface Water, Ecological and Cultural Heritage sites are addressed in separate sections. The following significance criteria have been used:

 

Impact

Significance Criteria

Severe adverse impact

 

More than 1 major river crossing. Significant disruption during construction of other structures. Deep cuttings for majority of route. Large quantity of material to be excavated on site. Large quantity of material to be imported and exported on local roads. Over 150 properties within 100m of the route. Significant disruption to road users from crossing existing roads.

Major adverse impact

 

1 major river crossing. Major disruption during construction of other structures. Deep cuttings for large sections of route. Major amount of material to be excavated on site. Major quantity of material to be imported and exported on local roads. Between 100 to 150 properties within 100m of the route. Major disruption to road users from crossing existing roads.

Moderate adverse impact

 

Moderate disruption during construction of structures. Deep cuttings at a number of locations along route. Moderate amount of material to be excavated on site. Moderate quantity of material to be imported and exported on local roads. Between 50 to 100 properties within 100m of the route. Moderate disruption to road users from crossing existing roads.

Minor adverse impact

Minor disruption during construction of structures. Deep cuttings at few locations along route. Small amount of material to be excavated on site. Small quantities of material to be imported and exported on local roads. Less than 50 properties within 100m of the route. Minor disruption to road users from crossing a small number of existing roads.

No impact

No significant effect.

Minor beneficial impact

Employment of local construction companies/staff during the construction period.

Moderate beneficial impact

Employment of local construction companies/staff during the construction period. Use of local materials and facilities.

 

17.2  Phasing of Construction

Whilst there is as yet no definite plan for the phasing of the actual construction works, notwithstanding the broad phasing indications given in the National Roads Needs Study, it has nevertheless been assumed for the purpose of analysing construction impacts that the scheme may be constructed in three phases as given below:

      Phase 1    Macroom Bypass

      Phase 2    Macroom to Ballincollig

      Phase 3    Ballyvourney to Macroom

As the Yellow route follows the existing N22 there is greater scope for the proposed construction phasing to still provide operational benefits following completion of each phase of the work.  Phase 1 would be constructed along the proposed alignment between Carrigaphooca and Coulcour, where the construction of junctions with the existing N22 at the tie-in points would facilitate continued access to the N22 following completion of this Phase.  The junction at Coulcour will coincide with the proposed R584 junction.  There would be very little redundant construction to make this a stand-alone phase.

Also, in terms of the Yellow route benefits, the proposed Phase 2 works could be opened in sections as construction was completed.  On the negative side however, construction close to and crossing the existing N22 will tend to cause disruption to existing traffic during construction of the new road and could take relatively more time to construct due to the phasing requirements for work under traffic.

With respect to the proposed Phase 3 works, should the Green/Link route be used, the Macroom bypass (Phase 1) would require the construction of an approximately 1km long section of temporary road to complete connection to the existing N22 near Carrigaphooca, until Phase 3 is completed.

To the east of Macroom, should the Yellow or Blue routes be used, the Macroom bypass (Phase 1) may require the construction of a 200m long link to the existing N22 at the R584 junction involving the construction of bridge to cross the Sullane River.

It should be noted that the Green route does not intersect the existing N22 and therefore, should this route be preferred, the construction of the Macroom bypass (Phase 1) would still need to proceed as proposed to provide for the planned early relief of congestion in Macroom.  Additional provision could then be made in the design and subsequent construction of the Green route to allow for connection to the bypass and the N22 in the final completed scheme.

 

17.3  General Description of Works

The construction work typically carried out during each Phase of the scheme is as follows:

Clearing

Clearing and grubbing of vegetation along the length of the road corridor.  Typically, this work would be limited to the plan “footprint” or effect of the road embankments / cuttings.
The cleared vegetation would be either disposed of off site or prepared (eg mulched) and stored for future on site landscaping.
Machinery/resources typically involved with this element of the work would include; tree lopping crews with power saws, vegetation mulching equipment, excavation plant and haulage vehicles.

Stripping of topsoil. 

Again, this work would be carried out along the length of the chosen route and limited to the plan “footprint” of the road embankments / cuttings.
The stripped topsoil materials would be either disposed of off site or hauled to stockpile sites if deemed suitable for future usage on site (eg landscaping).

Machinery/resources typically involved with this element of the work would include excavation plant and haulage vehicles.

Excavation of cuttings

Excavation of cuttings would include excavation of both rock and soil materials, suitable and unsuitable for road construction.  Depending on a number of factors, including the chosen route, the phasing of the work and the type(s) of materials encountered, activities relating to the usage or disposal of the excavated material will vary.  In general though the usage and disposal activities will include one or more of the following:

·       Haulage of excavated materials to adjacent or nearby fill areas for construction of embankments, not requiring the use of the existing road network for haulage.

·       Haulage of excavated materials to fill areas associated with construction of the scheme, but requiring haulage along the existing road network.

·       Haulage of excavated materials surplus to current requirements to stockpile(s) for future use on the scheme.  Possibly requiring the use of the existing road network for haulage.

·       Haulage of excavated materials off site for disposal.

The above activities are covered in more detail in the following parts of this Section.

Machinery/resources typically involved with this element of the work would include excavation plant, rock breaking equipment, water bowsers and haulage vehicles.

Blasting of unweathered rock in deeper cuttings may also be considered in lieu of mechanical methods for excavation.

Haulage of surplus material to stockpile sites

Haulage of surplus material to stockpile sites would be carried out where suitable areas can be located and if future need for the material is identified for construction of the scheme.  The location of stockpile sites would be dependant on the route option(s) chosen for the scheme.  The haulage to stockpile sites could be via the construction corridor or on the existing road network.  Machinery/resources typically involved with this element of the work would include haulage vehicles, water bowsers, spreading and compaction plant.

Haulage of surplus material off site for disposal

Haulage of surplus material off site for disposal would be carried out where the excavated material is unsuitable for the construction of embankments or a future need for the material in the construction of the scheme is not identified.  The location of disposal sites would be determined based on local needs and relevant legislation covering this activity.  Haulage of the material for disposal would be via the existing road network.  Machinery/resources typically involved with this element of the work would include haulage vehicles and water bowsers.

Haulage of material to fill areas and construction of embankments

Haulage of material to fill areas and construction of embankments would be carried out at various sections along the length of the scheme.  The actual locations of this work depends on the chosen route.  Material may be hauled from:- adjacent or nearby cut areas via the construction / route corridor, along the existing road network from cut areas elsewhere on the scheme, stockpile sites established earlier during the construction of the scheme or borrow sites separate to the construction of the scheme.  Machinery/resources typically involved with this element of the work would include haulage vehicles, water bowsers, spreading and compaction plant.

Construction of surface and subsurface drainage structures

Construction of surface and subsurface drainage structures would be carried out as required to ensure adequate drainage for road surfaces, protection and durability of the works, and to minimise or avoid impact on local communities, current land uses and the environment.  Machinery/resources typically involved with this element of the work would include delivery trucks, storage compounds, excavation plant, haulage vehicles compaction plant and water bowsers.

Construction of pavements

Construction of pavements would be carried out along the entire length of the route.  The type of pavement would vary little throughout the route, however the need to vary the pavement design may arise depending on local conditions and constraints.  Machinery/resources typically involved with this element of the work would include pavement material delivery trucks, road paving plant, compaction and finishing plant.

Construction of structures

Construction of structures would be carried out at a number of locations along the route for the crossing of water courses and existing roads.  Machinery/resources typically involved with this element of the work would include material delivery trucks, concrete placement, compaction and finishing plant.

Other miscellaneous works

Other miscellaneous works would typically include, but without limitation to, the installation of road markings, roadside safety fencing, street lighting, signage, landscaping and boundary fencing.  These activities would be carried out over a limited period of time have significantly less impact.

 

17.4  Existing Services

Identification of existing major service/utility networks within the Study Area was carried out during the Constraints Study.  The description of these findings is contained in Section 3 of the Constraints Report, with more specific information in Section 3.5 of the same Report.

In summary, the following existing service/utility networks and associated infrastructure were identified within the Study Area:

·       Water supply and sewer drainage servicing the towns of Macroom, Ballyvourney and Killnamartery.

·       Eircom fibre optic network between most major centres within the Study Area, running mainly along national and regional roads (including N22, R584, R585, R590 and R618).

·       Eircom overhead network along approximately 80 to 90% of the local road network

·       ESB Major power supply crossing west to east across the Study Area with connection to the north and south as well

·       5 ESB substations

Potential impact on these services due to each of the proposed routes has been examined and allowance made within the current cost estimate for the works.

All impacts on services/utilities by the chosen route would be considered in greater detail during the design stages of the scheme.  Adjustments to the alignment of the chosen route, would be made during the design stages where necessary to avoid or minimise impact on these services/utilities.

Where necessary, relocation and/or adjustments to existing services/utilities would be designed and constructed as part of the overall scheme in accordance with relevant legislative and authority requirements in order to avoid or minimise disruption of these services to the community.

 

17.5  Assessment of Route Options

17.5.1              Phase One – Macroom Bypass – (Coolcour to Carrigaphooca)

Yellow

Yellow Route - Y/05, Y/06 and Y/06a (Nodes 5 to 7a)

Severe Adverse Impact.  Construction of structures to cross the River Laney near Laney and the Sullane River near the intersection of the existing N22 and R584 could result in potential pollution of these watercourses and impact on the amenity.

Disruption to traffic would be expected, caused by the crossing of, tying into and closure of a number of existing roads along this section of the route, including the major roads N22, R618 and R582.

Less than 50 dwellings are located within 100m of this section of the route.

 

17.5.2              Phase Two – Macroom to Ballincollig

Yellow

Y/07 (Nodes 7a to 8)

Severe Adverse Impact.  Construction of a structure to cross the Lee Valley Reservoir near Coolcour and the proximity of the earthworks operation to the shore of the Reservoir create significant potential for pollution of the Reservoir waters and an impact on their amenity. 

Disruption to traffic would be expected at several locations along the existing N22 as well as on other existing side roads due to the alignment of this route.

Very few dwellings would be located with 100m of this section of the route.

Y/08 (Nodes 8 to 11)

Moderate Adverse Impact.  Deep cutting(s) at western end of this section of the route.  New road does not intersect existing N22 alignment except at the very western end, therefore only a moderate disruption to traffic would be expected at side roads to the existing N22. 

There are very few dwellings located with 100m of this section of the route and no major river crossings to be constructed.

Y/09 (Nodes 11 to 12)

Major Adverse Impact.  Close proximity to the River Bride and associated floodplain present the risk of pollution and impact on amenity during construction. 

Significant disruption to traffic would be expected during construction due to the very close alignment of the new route to the existing N22.

Less than 50 dwellings are located within 100m of the new roadway.

Y/10 (Nodes 12 to 15)

Major Adverse Impact.  Close proximity to the River Bride and a river crossing (near Ovens) as well as construction on the associated floodplain present the risk of pollution and impact on amenity.

The route crosses a few minor side roads to the N22, which would be expected to cause moderate disruption to traffic.

Less than 50 dwellings are located within 100m of the new roadway.

Y/11 (Nodes 15 to 16)

Major Adverse Impact.  This short section of road joins the existing N22 alignment near Ovens.  Construction of this interchange, as well as the proximity to the town of Ovens, would cause major disruption to traffic using the existing N22.

Green

G/05 (Nodes 6 to 9)

Major Adverse Impact.  During the construction of the structure to cross the River Laney near Shanakill there would be a risk of pollution of the water course and an impact on the amenity of the surrounding area.

There are several crossings of existing minor roads which would cause moderate disruption to traffic using these roads.

Very few dwellings are located within 100m of this section of the route.

G/06 (Nodes 9 to 14)

Severe Adverse Impact.  During the construction of the major (400m long) Reservoir crossing near Fergus as well as a minor crossing of the Glashagarriff River near Shanavagha there is a significant risk of pollution to these water courses and an impact on the amenity of the surrounding area.

Crossings of two major roads (R618 and R619, east and north of Coachford respectively) as well as a number of other minor roads would result in a significant degree of disruption to traffic.

Less than 50 dwellings are located with 100m of this section of the route.

G/07 (Nodes 14 to 16)

Major Adverse Impact.  During the construction of the structure to cross the River Bride near Ovens there is a risk of pollution to the water course and impact on amenity in the surrounding area. 

Connection to the exiting N22 at Ovens as well as a few minor road crossings would cause major disruption to traffic using these roads.

There are less than 50 dwellings located within 100m of the new section of the route.

Red

R/10 (Nodes 7 to 7b)

Major Adverse Impact.  Construction of a crossing of the River Laney near Macroom would present a significant risk of pollution to the River. 

In addition, proximity to the town of Macroom and the crossing of a few existing roads leading into the town would create major disruption to traffic.

R/02 (Nodes 7b to 13)

Severe Adverse Impact.  During the construction of the major (150m long) structure to cross the Lee Valley Reservoir near Carrigadrohid there is a significant risk of pollution to the Reservoir and an impact on the amenity of the surrounding area. 

A crossing of the R618 east of Macroom as well as a nearby cutting would result in moderate to major disruption of traffic using this road.

Less than 50 dwellings are located within 100m of this section of the route.

R/03 (Nodes 13 to 14)

Major Adverse Impact.  While there are no crossings of major rivers/water courses along this section of the route, the new road traverses countryside directly adjacent to the Reservoir and does cross a few smaller streams that discharge into the Reservoir.  Therefore, the risk of pollution and impact on the amenity of the area is significant.

A crossing of the R619 near Rooves Beg would create a moderate to major disruption of the traffic using this route.  A number of other minor roads would also be affected along this section of the route with disruption to traffic expected.

Less than 50 dwellings are located within 100m of this section of the route.

Blue

B/01 (Nodes 7 to 10)

Severe Adverse Impact.  During the construction of the major (200m long) structure to cross the Lee Valley Reservoir near Ballytrasna as well as a crossing of the River Laney near Macroom (same as route section R/01) there is a significant risk of pollution of these waters and an impact on the amenity of the surrounding area.

A crossing of the R618 east of Macroom would result in moderate disruption to traffic using this road.

Less than 50 dwellings are located within 100m of this section of the route.

B/02 (Nodes 10 to 11)

Moderate Adverse Impact.  Disruption to traffic expected during construction of interchange with N22.

Very few dwellings are located within 100m of this section of the route.

B/03 (Nodes 11 to 12a)

Major Adverse Impact.  Construction of a major crossing of the River Bride near Garryhesty as well as being located on the associated floodplain present a significant risk of pollution and impact on amenity during the construction.

Moderate to major disruption to traffic would be expected due to crossing of the R585 and a number of other minor roads.

Less than 50 dwellings are located within 100m of this section of the route.

B/04 (Nodes 12a to 15)

Major Adverse Impact.  Close proximity to the River Bride and a River crossing (near Ovens) as well as construction on the associated floodplain present the risk of pollution and impact on amenity during the construction.

The new section of road does not intersect the existing N22 alignment except at the very western end near Ovens, therefore only a moderate disruption to traffic would be expected at side roads to the existing N22.

Less than 50 dwellings are located within 100m of the new roadway.

Links

L/03 (Node 9 to 13)

Severe Adverse Impact.  During construction of the major crossing of the Lee Valley Reservoir and this route’s proximity to the shore of the Reservoir there would be a significant risk of pollution and an impact on the amenity of the surrounding area.

The route also crosses two existing major roads (R618 and R619) as well as a few minor roads, which would create major disruption to the traffic on these roads.

L/04 (Node 8 to 10)

Major Adverse Impact.  Construction of an interchange with the existing N22 west of Crossmahon would create significant traffic disruption.  This route also crosses a few other minor roads.

There are no major river crossings, however the route does cross the Buingea River, which discharges into the Reservoir.  There is therefore, a risk of pollution during the construction.

L/06 (Node 12 to 12a)

Minor Adverse Impact.  There are no major river or existing road crossings on this short link road (between Y/09 and B/04).  However, the route is located on the floodplain for the River Bride, which therefore presents the risk of pollution to the water course.

 

17.5.3              Phase Three – Ballyvourney to Macroom

Yellow

Y/01 (Nodes 1 to 2)

Major Adverse Impact.  Construction of the connection and improvement to the existing N22 between this junction and the existing wide single carriageway west of Ballyvourney would create major disruption to the traffic using the N22.  The route also crosses a few other minor roads.

There are very few dwellings located within 100m of this section of the route.

Y/02 (Nodes 2 to 3)

Minor Adverse Impact.  There are no major river crossings or disruptions to existing major roads along this short length of the route.

Some disruption to traffic would likely occur at the few minor roads crossed by this section of the route.

There are very few dwellings located within 100m of this section of the route.

Y/03 (Nodes 3 to 3a)

Minor Adverse Impact.  There are no major river crossings or disruptions to existing major roads.  However, construction of a crossing of the main road between Ballyvourney and Clondrohid would create some disruption to the normal traffic using this road.

Less than 50 dwellings are located within 100m of this section of the route.

Y/04 (Nodes 3a to 5)

Severe Adverse Impact.  Construction of two major river crossings (River Sullane near Inchinahoury and River Foherish near Carrigaphooca) as well as the route’s location on the associated floodplains present a significant risk of pollution and impact on the amenity of these water courses.

The route runs close to the alignment of the existing N22 for much of this particular length, crossing the N22 at two locations.  There would therefore, be significant impact on the traffic using this route.  Several minor roads are also affected along the alignment of this section of the route.

Less than 50 dwellings are located within 100m of this section of the route.

Green

G/01 (Nodes 1 to 2)

Moderate Adverse Impact.  Construction of the connection to the existing N22 west of Ballyvourney would create some disruption to the traffic using this road.  The route also crosses a few other minor roads.

There are very few dwellings located within 100m of this section of the route.

G/02 (Nodes 2 to 3)

Minor Adverse Impact.  There are no major river crossings or disruptions to existing major roads along this short length of the route.

Some disruption to traffic would likely occur at the few minor roads crossed by this section of the route.

There are only a few dwellings located within 100m of this section of the route.

G/03 (Nodes 3 to 4)

Minor Adverse Impact.  There are no major river crossings or disruptions to existing major roads. However, construction of a crossing of the main road between Ballyvourney and Clondrohid would create some disruption to the normal traffic using this road.

There are only a few dwellings located within 100m of this section of the route.

G/04 (Nodes 4 to 6)

Major Adverse Impact.  Construction of a major crossing of the River Foherish near Clondrohid present significant risk of pollution and loss of amenity.

A major crossing of the R582 as well as crossing of other minor roads into Macroom and Clondrohid would create moderate to major disruption to traffic during construction.

There are less than 50 dwellings located within 100m of this section of the route.

Links

L/01 (Nodes 4 to 5)

Major Adverse Impact.  Construction of a major crossing of the River Foherish near Clondrohid and the location of the route within the near catchment of this river present significant risk of pollution and loss of amenity.

Moderate disruption to traffic on several minor roads crossing this section of the route would be expected during construction.

 

17.6  Mitigation Proposals

Detailed mitigation proposals for the preferred route would be developed during the detailed assessment and design stage. In general, proposals for the mitigation of negative construction impacts would be similar for all the route options.

Mitigation would include working in accordance with relevant legislation and adopting good working practices.  Appropriate specific working methods would be developed to protect areas of environmental importance.  Site supervision, involvement of regulatory bodies, local community/stakeholder liaison, traffic management and signing would also be key to minimising construction impacts.

Mitigation measures would include programming to minimise environmental disturbance (e.g. working hours, avoiding ecologically sensitive periods such as fish spawning and bird nesting), protection of sensitive sites, pollution control measures, management of site drainage and run-off, supervision and control of deliveries and storage, waste storage, waste disposal management and traffic management.

 

17.7  Conclusions

The recommended preferred route, chosen to minimize the potential for negative impact caused by construction activities, is as follows:

·       Nodes 1 to 3 – Green route

·       Nodes 3 to 6 – Green route

·       Nodes 6 to 16 – Blue route to Node 11 then Yellow route to Node 16

Further explanation regarding this recommendation is contained in the Route Selection Matrix, which has been provided in Appendix 21 of this report.

 

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