Arklow Sewerage Scheme Contract 1 Œ South Green & Harbour Road

Wicklow County Council

Project: Arklow Sewerage Scheme Contract 1 œ South Green & Harbour Road Sewer Replacement Foreshore Report November 2011

Arklow Sewerage Scheme SG & HR Foreshore Report

CONTENTS 1 INTRODUCTION 2

1.1 Terms of Reference 2

1.2 Background 2

1.3 Proposed Infrastructure 3

1.4 The Foreshore Act 1933 to 2003 3

1.5 Current Infrastructural Deficiencies 3 2 PLANNING REQUIREMENTS 7

2.1 Foreshore Planning 7

2.2 EPA/Waste Water Discharge Licence 7

2.3 Part 8 Planning 7 3 STANDALONE INFRASTRUCTURE 8 4 DESIGN ASSUMPTIONS 9

4.1 Existing Sewers and Proposed Upgrades 9

4.2 Submersible Pump Stations 10 5 WORKS IN THE FORESHORE 12 6 OUTFALL WORKS TO BE DECOMMISSIONED IN ULTIMATE SCHEME 13 7 CONCLUSIONS 14

APPENDIX A - DRAWINGS

WYG Ireland Ltd.

PH McCarthy House, Nutgrove Office Park, Nutgrove Avenue, Rathfarnham, Dublin 14 P:\800 Project Numbers\857 Arklow Main Drainage\85701 South Green & Harbour Rd\Reports & Contract Documents\17F SG & HR Foreshore Report\SG & HR Foreshore Report.doc November 2011 1

Arklow Sewerage Scheme SG & HR Foreshore Report

1 INTRODUCTION

1.1 Terms of Reference

Arklow Town Council (ATC) in conjunction with Wicklow County Council (WCC) are promoting the Arklow Sewerage Scheme. The scheme, which is required to meet current National and European environmental legislation, incorporates the construction of a new Waste Water Treatment Works together with a pumping station, transfer pipelines and long sea outfall.

Contract 1 includes advance works identified to rectify the following;

1. Existing sewers do not have sufficient capacity to convey existing and future flows, 2. Existing sewers are in poor structural condition which gives rise to regular collapse, 3. Flooding and surcharge of the existing system gives rise to public health risks.

This contract is included in the Water Services Investment Programme (2010 œ 2012) as a contract to start within the period of the Programme.

This report accompanies the Foreshore Application Form and Drawings and details the extent and details of the required works in the foreshore area. The application is completed in accordance with —The Foreshore Act 1933 to 2003 œ General Guidance Notes“.

1.2 Background

The Arklow Sewerage Scheme includes the construction of the following;

• 18,000 PE Waste Water Treatment Facility (WwTW), • Approx. 1km long sea outfall, • Interceptor Sewers along North and South Quay, • Pumping station and rising main to pump wastewater to the proposed WwTW, • Advanced works along South Green and Harbour Road.

The design and construction of the interceptor sewers, pumping station and Waste Water Treatment Works has been delayed due to appeals to the High Court regarding the EIS for the WwTW. Litigation was ongoing in relation to the EIS approval for the Wastewater Treatment Works for in excess of 10 years which has restricted the provision of the required wastewater treatment services in Arklow to meet current legislation, the Urban Wastewater Treatment (UWWT) and Water Framework Directive (WFD) Regulations. An Appeal on the High Court decision was heard in the Supreme Court on 2nd December 2009. The Supreme Court judgement was issued on the 21st July 2011. This judgement confirmed the decision of the High Court and effectively confirmed the planning approval for thewwastewater Treatment Works.

Due to the above restrictions, the design of Contract 1 - South Green & Harbour Road Sewer Replacement has been carried out to enable these advanced works to be constructed as standalone infrastructure in advance of the remainder of the Arklow Sewerage Scheme. There are considerable benefits associated with the progression of these works which are identified in this report.

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Arklow Sewerage Scheme SG & HR Foreshore Report

The proposed interceptor sewers are designed to collect most of the combined flows currently discharging direct to the Avoca River and then pumping these flows to the proposed WwTW.

Contract 1 is designed to form an integral part of the interceptor sewers and includes the construction of new storm and combined sewers and outfalls. Two no. storm outfalls will be permanent and the 2 no. combined outfalls will be temporary, becoming redundant when the proposed interceptor sewers are constructed.

It is programmed that the tender process for Contract 1 will commence in February 2012.

1.3 Proposed Infrastructure

The proposed infrastructure for Contract 1 regarding any foreshore works includes the following;

• Construction of a permanent storm outfall to the Avoca River mounted directly on the existing quay wall at South Green, • Construction of a permanent storm outfall to the Avoca River mounted directly on the existing quay wall at Harbour Road, • Construction of a temporary combined outfall to the Avoca River mounted directly on the existing quay wall at South Green. This outfall will become redundant upon construction of the interceptor sewers, • Construction of a temporary combined outfall to the Avoca River mounted directly on the existing quay wall at Harbour Road. This outfall will become redundant upon construction of the interceptor sewers.

For details, refer to the enclosed drawings in Appendix A that accompany this application report.

1.4 The Foreshore Act 1933 to 2003

The following is a list of documents that accompany the foreshore license application;

• Completed application form, • Ordnance Survey Map of 6“ scale (latest edition) showing the precise area and the hectarage involved below the line of high water of medium tides clearly marked on the Map, • Longitudinal section showing clearly how such works will be laid in relation to the surface of the seabed and having delineated on it the lines and levels of high and low water of Spring tides, • Certified copy of the Company‘s Memorandum and Articles of Association and Certificate of Incorporation of a Limited Liability Company/Rule Book/Constitution for a club or Co-Operative Society as appropriate to the particular circumstance, • This report.

1.5 Current Infrastructural Deficiencies

The South Green and Harbour Road sewers form a critical part of the Arklow Sewerage network as most of the wastewater flows in the southern part of the town gravitates towards WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

this low-lying area and pass through these sewers prior to discharge in the Avoca River. The Arklow Sewer Modelling Phase 2 & 3 Reports completed by WYG and commissioned by Wicklow County Council in conjunction with Arklow Town Council, sets out how the existing network operates, identifies the South Green and Harbour Road sewers as being in critical need of upgrade/replacement and details the impacts on the existing drainage infrastructure based on future development.

The infrastructural deficiencies of the South Green and Harbour Road sewers include the following;

• Lack of capacity in the existing sewer network, • Existing deficient sewers which are in poor structural condition giving rise to collapse hence requiring emergency repairs, • Build up of silt and debris in the existing sewers, • Backflows in the sewers during high tide which prevents against the free discharge of flows to the river, • Low lying area with ground levels less than 1m OD Malin.

All the above factors contribute to the regular flooding and sewage discharge in the South Green and Harbour Road areas.

The Arklow Sewer Modelling Study identified deficiencies in the sewer network due to the lack of sewer capacity and the poor condition of a number of the existing sewers. The recommendations from the above report are incorporated in Contract 1.

It has been reported by Arklow Town Council (ATC) that the sewers/culverts in this area undergo regular collapse. ATC was required on a number of occasions to conduct emergency repair works on these sewers/culverts to maintain flows and prevent flooding. As a result, a number of CCTV surveys have been recently completed in this area to ascertain the structural condition and the extent of silt and debris accumulation. It has been observed that a number of the sewers are at a near collapse condition and sizable infiltration was noted. There is evidence of siltation in the pipes/culverts which require regular jetting and cleaning by ATC (refer to below photos). The condition of the above sewers/culverts is a contributing factor to the regular flooding in this area.

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

Photo 1.1 œ Evidence of siltation/debris in existing culvert

Photo 1.2 œ Evidence of siltation/debris in existing twin pipe

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

Photo 1.1 œ Evidence from CCTV Survey of structural deficiency in existing culvert

This area of the town in question is low lying with ground levels less than 1m OD Malin. In the event of storm conditions, combined with high tides, the sewage and storm flows in the sewers/culverts are restricted and cannot discharge freely to the Arklow River. This results in stagnation in the sewers, backflows, and eventually flooding in the area. Flooding, through the manholes, occurs in South Green approximately twice per year whereby the road becomes impassable. Such flooding events have been discussed and minuted in meetings with ATC and Office of Public Works (OPW).

Notwithstanding the flood damage caused to the properties, this has also given rise to public health issues with the discharge of raw sewage due to the surcharging of the combined sewers/culverts.

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

2 PLANNING REQUIREMENTS

2.1 Foreshore Planning

Following on from the enactment of the Foreshore and Dumping at Sea (Amendment) Act 2009, responsibility for certain foreshore functions has transferred to the Minister for the Environment, Community and Local Government with effect from 15th January 2010. The Foreshore Acts require that a lease or licence must be obtained from the Minister for the carrying out of works or placing structures or material on, or for the occupation of a removal of material from, State-owned foreshore which represents the greater part of the foreshore.

2.2 EPA/Waste Water Discharge Licence

WCC applied to the EPA for a Wastewater Discharge Licence for the Arklow Sewerage Scheme in December 2007. To date, no decision has been received on the application. WCC are now liaising with the EPA regarding the requirements for a discharge licence for the scheme. WCC anticipate that an application for a licence together with an accurate project programme will be submitted to the EPA in January 2012.

A copy of the contract documents for Contract 1 will be submitted to the EPA for inclusion in the Wastewater Discharge Licence application.

2.3 Part 8 Planning

The proposed development (2 No. submersible pump stations) for Contract 1 is a prescribed development for the purposes of Section 179 of the Planning and Development Act 2000 (local authority own development) and planning for the development is sought under Part 8 Article 80(1) of the Planning and Development Regulations 2001 to 2006. While the proposed development is not a prescribed development requiring (environmental) assessment under Section 176 of the Planning and Development Act, ATC in conjunction with WCC commissioned WYG Ireland to complete a Part 8 Planning Report which includes an environmental assessment of the proposed works.

It should be noted that Part 8 Planning is not required for sewers.

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Arklow Sewerage Scheme SG & HR Foreshore Report

3 STANDALONE INFRASTRUCTURE

The Arklow Sewerage Scheme will include the design and construction of interceptor sewers (Contract 2) on the north and south side of the river. These will convey flows to a proposed pump station at North Quay (Contract 3) which in turn will pump to a new Wastewater Treatment Works (Contract 3) located in the townland of Seabank approx. 2.5km north east of Arklow. In the interim, Contract 1 is designed to act as standalone infrastructure to eliminate the environmental and structural deficiencies as identified in this report.

Contract 1 works are designed to enable ease of connection to the proposed southside interceptor sewer which forms an integral part of the Arklow Sewerage Scheme.

The proposed upgrades to the existing network together with the surface water sewer, combined sewer and submersible pump stations will provide additional storage during storm events.

Although, the proposed works does not include for the design of two separate systems, it does allow provision for future separation with the two pipelines. The construction of surface water sewers and the diversion of connections from the combined sewers to the proposed surface water sewers, will reduce the loading on the combined sewers and will also reduce the pumping and treatment costs in the future as this surface water pipe will discharge directly to the Arklow River. The removal of the Combined Storm Overflows (CSO‘s) is considered best practise. This will provide environmental benefits upon completion of the Arklow Sewerage Scheme as the discharge of sewage to the river will be reduced.

The 2 No. dry weather flow pump stations are required to overcome the tidal outfall restrictions in these low lying areas. This ensures that the proposed sewers will act as a trunk main for storage during high tide and rainfall events.

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

4 DESIGN ASSUMPTIONS

The design of Contract 1 works has incorporated the recommendations of the Arklow Sewer Modelling Study Phase 3 Report œ 2010. The contract includes the construction of new sewers and the replacement of deficient existing sewers/culverts.

4.1 Existing Sewers and Proposed Upgrades

The existing sewers in the study area are structurally deficient and are not capable of conveying the current flows to the Arklow River. Contract 1 includes the construction of new combined and surface water sewers which will discharge to the Arklow River adjacent to the existing outfalls. The Arklow Sewer Modelling œ Phase 3 Report identified the existing sewers and combined storm overflows (CSO‘s) as deficiencies.

The proposed combined sewers are designed to be connected directly to the new interceptor sewer (when constructed) which will convey flows to the proposed Wastewater Treatment Works. Invert levels have been designed to consider future levels of the interceptor sewer. The proposed storm sewers will discharge directly to the river following the re-connection of the existing surface water sewers and culverts to the proposed storm sewers. These storm flows will not be connected to the proposed interceptor sewer and shall be retained as part of the long term works.

South Green The existing sewer system along South Green includes the following; • Twin 450mm dia. storm pipe (the twin pipe has replaced sections of an old brick culvert, part of the culvert still exists); • 450mm dia. combined sewer.

The proposed sewers to be constructed in South Green include the following; • A proposed 450mm dia. concrete surface water sewer. This sewer will discharge directly to the Arklow River at approx. -0.51m OD (approx. bed level of the river at the quay wall); • A proposed 900mm dia. concrete combined sewer. This combined sewer will connect to a proposed submersible pump station which will pump the flows directly to the river where a new outfall will discharge at approx. -0.39m OD (approx. bed level of the river at the quay wall). During storm events when flows exceed pump capacity, an overflow will convey flows to the river.

Harbour Road The existing sewer system along Harbour Road includes the following; • 375mm dia. combined sewer; • 300mm dia. storm sewer; • 600mm dia. storm sewer.

The proposed sewers to be constructed in Harbour Road include the following;

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Arklow Sewerage Scheme SG & HR Foreshore Report

• A proposed 900mm dia. concrete surface water sewer. This sewer will discharge directly to the Avoca River at approx. -1.94m OD (approx. bed level of the river at the quay wall);

• A proposed 525mm dia. concrete combined sewer will be constructed in Harbour Road. This combined sewer will connect to a proposed submersible pump station which will pump the flows directly to the river where a new outfall will discharge at approx. - 1.23m OD. During storm events when flows exceed pump capacity, an overflow will convey flows to the proposed 900mm dia. surface water outfall.

The above proposed sewer infrastructure will have sufficient capacity both in the short term and the long term, i.e. post interceptor sewer construction, to convey the required flows.

4.2 Submersible Pump Stations

The works includes the design and construction of 2 no. submersible pump stations located at the junction of South Green/South Quay and Harbour Road/South Quay. The pumping stations are to be situated in chambers immediately upstream of sewer outfalls located in the quay wall. Pumping is required to carry the sewer‘s 3 x dry weather flows of approx. 9 l/s and 6l/s (South Green/Harbour Road respectively) past Tideflex-type check valves which are to be located in chambers. During storm events, when the pumping capacity is exceeded, the pumps will be by- passed and the flows will pass directly to the Avoca River via the new outfalls.

Table 4.1 & 4.2 below shows the estimated flows generated by the calibrated computer model in the existing sewers/culverts during different return period storms.

Table 4.1 œ Estimated Flow Rates in existing Sewers/Culverts in South Green. Full Capacity Flow DWF 1yr storm 5yr storm (Without Surcharge) [l/s] [l/s] [l/s] [l/s] Twin 450mm dia. Storm 2 173 242 164.0 Sewer at South Green 450mm dia. Combined Sewer at South Green 3 126 141 17.0

Total for South Green 5 299 383 181

Both the existing storm sewer and combined sewers do not have sufficient capacity to convey flows to the river. The proposed new pipes along South Green will provide the required capacity to convey the above flows both in the short term and the long term i.e. post interceptor sewer construction.

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

Table 4.2 œ Estimated Flow Rates in existing Sewers/Culverts in Harbour Road. Full Capacity Flow DWF 1yr storm 5yr storm (Without Surcharge) [l/s] [l/s] [l/s] [l/s] 375mm dia. Combined 2 110 156 93.0 Sewer at Harbour Road 300mm dia. Storm Sewer at 2 32 63 58.0 Harbour Road 600mm dia. Storm Sewer at 2 100 190 101.0 Harbour Road Total for Harbour Road 6 242 409 252

The existing combined sewer and 375mm dia. surface water sewer do not have sufficient capacity to convey flows to the river. The proposed new pipes along Harbour Road will provide the required capacity to convey the above flows both in the short term and the long term i.e. post interceptor sewer construction.

By re-connecting the surface water connections from the existing combined sewers/culverts to the proposed surface water sewers, it reduces the DWF‘s in the above pipes.

The pumps are an essential part of the design to prevent odour problems and possible septicity in the sewers during periods of extended dry and warm weather. This will ensure that a steady flow is maintained in the sewers and prevents stagnation as the invert levels of the sewers can be below the tidal levels in the Avoca River.

The pumps shall operate on a duty/standby basis. The operation of each unit shall be controlled by independent automatic controls based on the level of sewage in the sump with fault signals hard wired interlocked with the starter contacts of the pumps.

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Arklow Sewerage Scheme SG & HR Foreshore Report

5 WORKS IN THE FORESHORE

The works in the foreshore area are likely to consist of the following;

• Temporary damming of the proposed working area to provide safe working conditions to construct the wall mounted outfalls. These works may require temporary sheet piling or construction of a caisson in the river. The above works are considered to be temporary and will be subject to the design and construction of the temporary works designer (contractor) and in accordance with the requirements from Eastern Region Fisheries Board, Office of Public Works, Arklow Harbour Board etc. and all other state stakeholders.

The works will not impact on any pleasure boating and sailing and the Arklow Sailing Club and Harbour Master will be updated on all aspects of the works. The works are also located outside the navigation/shipping channel.

It is not anticipated that the works will impact on any erosion works as there will be no permanent alterations to the river bed/river channel. The bed will be restored to its original condition upon completion of the temporary works in the foreshore area.

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Arklow Sewerage Scheme SG & HR Foreshore Report

6 OUTFALL WORKS TO BE DECOMMISSIONED IN ULTIMATE SCHEME

Contract 1 is designed to minimise the extent of works which will be decommissioned upon commencement of the interceptor sewers as part of the Arklow Sewerage works. Considering the extent of the works and the tidal influences of the Avoca River, it is not possible to fully design the works without some works which will become redundant in the ultimate scheme. The proposed temporary combined sewer outfall at South Green and Harbour Road will be demolished and transferred to the southside interceptor sewer upon construction of the interceptor sewers estimated to be completed in year 2015. This is shown on the enclosed drawings.

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

7 CONCLUSIONS

This report accompanies the Foreshore Application Form and Drawings and details the extent and context of the required works in the foreshore area. The application is completed in accordance with —The Foreshore Act 1933 to 2003 œ General Guidance Notes“.

The South Green and Harbour Road Sewers form a critical part of the Arklow Sewerage network as most of the wastewater flows in the southern part of the town gravitate towards this low- lying area. The existing infrastructure has critical deficiencies including lack of capacity, poor structural condition giving rise to sewer collapse and tendency for debris and silt build up. These factors combined with the low-lying topography and tidal influence give rise to the regular flooding and public health risk due to the discharge of sewage.

Contract 1 identifies key works necessary to eliminate the infrastructural deficiencies, flooding and public health risks associated with the South Green and Harbour Road Sewers. This contract can be progressed as standalone infrastructure to provide significant environmental and drainage benefits to the town as set out in this report.

These works cannot proceed without the approval of a foreshore license as granted by the Department of Environment, Community and Local Government in accordance with The Foreshore Act 1933 to 2003.

WYG Ireland Ltd.

Arklow Sewerage Scheme SG & HR Foreshore Report

APPENDIX A

DRAWINGS

WYG Ireland Ltd.