Dublin Region Water Services - Dublin City Council
DUBLIN REGION WATER SERVICES STRATEGIC PLAN - 2009 THIS DOCUMENT SUMMARISES THE CURRENT STRATEGIC PLAN IN PLACE FOR THE DUBLIN REGION AND INCORPORATES THE OUTPUT FROM THE GREATER DUBLIN STRATEGIC DRAINAGE STUDY AND 1996 WATER SERVICES STRATEGIC PLAN. IT ALSO INCLUDES THE POLICIES IN THE EXISTING DEVELOPMENT PLANS COVERING WATER SUPPLY, DRAINAGE AND FLOOD RISK MANAGEMENT.
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 i Rev F02 TABLE OF CONTENTS (VOLUME 1) 1 INTRODUCTION AND SCOPE OF PLAN ___ 1
1.1 INTRODUCTION ___ 1
1.2 WATER SERVICES ACT, 2007 ___ 5
1.3 RELEVANT LEGISLATION ___ 7
1.4 WATER SERVICES STRATEGIC PLAN – REPORTS ___ 8
1.5 SCOPE OF WATER SERVICES STRATEGIC PLAN ___ 8
1.6 SYNCHRONISATION WITH OTHER RELEVANT PLANS AND PROGRAMMES ___ 9
1.6.1 Planning and Development ___ 9
1.6.2 Water and Environmental Quality Plans ___ 9
1.6.3 Waste Management Plans ___ 9
2 WATER SUPPLY ___ 10
2.1 WATER SUPPLY STRATEGIC PLAN - VISION ___ 10
2.2 WATER SUPPLY - LEVELS OF SERVICE ___ 10
2.2.1 Statutory, Customer and Other Levels of Service ___ 10
2.2.2 Water Supply - Levels of Service ___ 11
2.3 WATER SUPPLY STRATEGIC PLAN - OBJECTIVES ___ 12
2.3.1 Quality Objectives ___ 12
2.3.2 Capacity Objectives ___ 13
2.3.3 Asset Management Sustainability Objectives ___ 14
2.3.4 Resilient Supply and Operational Flexibility Objectives ___ 14
2.4 WATER SUPPLY STRATEGIC PLAN – DEMAND ___ 14
2.5 WATER SUPPLY - STRATEGIC MEASURES ___ 16
2.5.1 Asset Assessment and Options ___ 16
2.5.2 Water Services Operations – Strategic Measures ___ 17
2.5.3 Water Services Capital Investment – Strategic Measures ___ 17
2.6 WATER SUPPLY – WSSP IMPLEMENTATION & INVESTMENT PROGRAMME ___ 18
3 DRAINAGE ___ 19
3.1 STRATEGIC DRAINAGE PLAN - VISION ___ 19
3.2 STRATEGIC DRAINAGE PLAN - LEVELS OF SERVICE ___ 19
3.2.1 Statutory, Customer and Other Levels of Service ___ 19
3.2.2 Foul, Combined and Stormwater Drainage ___ 19
3.2.3 Foul Sewerage Systems - Levels of Service ___ 20
3.2.4 Stormwater System – Levels of Service ___ 24
3.3 STRATEGIC DRAINAGE PLAN - OBJECTIVES ___ 25
3.4 DRAINAGE - DEMAND FOR WATER SERVICES ___ 26
3.5 DRAINAGE SERVICES – STRATEGIC MEASURES ___ 26
3.5.1 Asset Assessment and Options .
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 ii Rev F02 3.5.2 Foul Drainage Measures ___ 27
3.5.3 Storm Drainage Measures ___ 28
3.6 DRAINAGE - PLAN IMPLEMENTATION & INVESTMENT PROGRAMME ___ 28
4 FLOOD RISK MANAGEMENT ___ 30
4.1 FLOOD RISK MANAGEMENT – VISION ___ 30
4.2 FLOOD RISK IN THE DUBLIN REGION ___ 30
4.3 FLOOD RISK MANAGEMENT - LEVELS OF SERVICE ___ 32
4.4 FLOOD RISK MANAGEMENT – OBJECTIVES ___ 33
4.5 FLOOD RISK MANAGEMENT – STRATEGIC MEASURES ___ 33
4.6 FLOOD RISK MANAGEMENT - IMPLEMENTATION ___ 35
5 DUBLIN REGION WATER SERVICES STRATEGIC PLAN – DELIVERY ___ 36
5.1 DELIVERY OF PLAN - CHALLENGES ___ 36
5.2 DELIVERY OF PLAN - INVESTMENT PROGRAMME ___ 36
6 ENVIRONMENTAL CONSIDERATIONS ___ 38
6.1 THE WATER FRAMEWORK DIRECTIVE ___ 38
6.2 THE SEA DIRECTIVE ___ 38
6.3 SUMMARY OF ENVIRONMENTAL CONSIDERATIONS ___ 39
LIST OF FIGURES Figure 1.1: Greater Dublin Region ___ 1
Figure 1.2: Greater Dublin Water Supply Area ___ 3
Figure 1.3: Greater Dublin Strategic Drainage Area ___ 4
Figure 1.4- Eastern River Basin District ___ 6
Figure 1.5 Relevant Legislation ___ 7
Figure 2.1: Future Need Demand Review ___ 15
Figure 3.2: Foul/ Combined Sewer System ___ 23
Figure 3.3: Regional Policies –GDSDS ___ 25
Figure 4.1: Extent of Flooding on the River Dodder, Hurricane Charlie, 1986 ___ 31
Figure 4.2: Dublin Coastal Flooding Protection Project – Project Extent ___ 35
APPENDICES (VOLUME 2) APPENDIX A: DUBLIN REGION WATER SERVICES INVESTMENT PROGRAMMES 2007- 2009
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 1 REV F02 1 INTRODUCTION AND SCOPE OF PLAN 1.1 INTRODUCTION The Water Services Act 2007 provides for the preparation of Water Services Strategic Plans (WSSPs) by Water Services Authorities and for their review at a minimum every 6 years. The Act provides that, where appropriate, a number of Water Services Authorities may make a combined Plan for their areas or parts of their areas where a common approach is required. In the Dublin Region, the four Dublin Local Authorities (Dublin City Council, Dun Laoghaire-Rathdown, Fingal and South Dublin County Councils) adopt a co-ordinated approach to the delivery of water services and this approach also applies to neighbouring areas in Counties Kildare, Meath and Wicklow (Figure 1.1).
It follows that an integrated Dublin Region Water Services Strategic Plan (DR-WSSP) is appropriate to these areas and services.
Figure 1.1: Greater Dublin Region
- Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 2 REV F02 This document details strategic plans in respect of:-
- Water Supply; where the Dublin Region Water Supply Area (DRWSA) is defined by the combined areas served by the Dublin Region Water Supply Schemes (Figure 1.2), namely, o Liffey Water Treatment Plants at Ballymore Eustace (Dublin City Council) and Leixlip (Fingal County Council) o Vartry Plant at Roundwood (Dublin City Council) o Dodder Plant at Bohernabreena (Dublin City Council) o Bog of the Ring Groundwater (Fingal County Council).
- Urban Drainage; where the Greater Dublin Strategic Drainage Area (Figure 1.3) is comprising: o Ringsend Wastewater Treatment Works (WwTW) catchment, including all of Dublin City and South Dublin, significant parts of Fingal and Dun LaoghaireRathdown Counties, and an area in South-East Meath including Ashbourne, Dunboyne and Clonee o Fingal County is also served by WwTWs at Swords, Malahide, Rush & Lusk, Balbriggan & Skerries and Portrane; o Southern Dun Laoghaire Rathdown County and Bray / Kilmacanogue in Co. Wicklow are served by the Shanganagh-Bray Scheme; o North and mid-Kildare covered by the Osberstown and Leixlip Wastewater Treatment Schemes
- Flood Risk Management; whereby a co-ordinated approach is adopted across the areas coinciding with the regional drainage catchment, including common policies for development control and sustainable storm water drainage.
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 3 REV F02 Figure 1.2: Greater Dublin Water Supply Area
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 4 REV F02 Figure 1.3: Greater Dublin Strategic Drainage Area
- Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 5 REV F02 1.2 WATER SERVICES ACT, 2007 The Water Services Act, 2007, provides that each Water Services Authority make a Water Services Strategic Plan (WSSP) with regard to the provision of water services in its functional area with three primary objectives;
- Protection of human health and the environment
- Provision of sufficient water services
- Support proper planning and sustainable development. The major legislative driver for action to improve water quality is the EU Water Framework Directive (2000/60/EC), being implemented in the Eastern Region (Figure 1.4) by the Eastern River Basin District (ERBD) Project. This project is developing measures to achieve “good” water quality in its river, coastal and transitional waters, to be achieved by 2015 at the latest. The River Basin Management Plans (RBMPs) being developed within the ERBD Project will be reflected in the WSSPs.
- Initially, the WSSP will be developed from available system knowledge, assisted by available technical studies and having regard to current development policies and plans in the region. Arising from the adoption of the WSSP, detailed monitoring will improve knowledge of the underlying condition and performance of water services assets. As a result, periodic reviews of the WSSPs, within a maximum 6 year timeframe, will provide for more detailed “bottom up” assessment of strategic needs to provide;
- Review of actual versus forecast out-turn costs;
- Review of changes in standards and levels of service requirements;
- Review of demand forecasts;
- Prepare revised WSSP for approval. In the case of the Dublin Region, this draft WSSP is prepared having regard to relevant major studies undertaken, in particular the following;
- Water Supply; the Greater Dublin Water Supply Strategic Study (GDWSSS 1996 and 2000 Review), including revised assessments carried out in 2006 in the context of the Water Supply ProjectDublin Region (WSP-DR), the Dublin Water Strategic Storage Study and other technical studies, detailing the status and priority requirements for water supply across the region
- Urban Drainage; the Greater Dublin Strategic Drainage Study (GDSDS) completed in 2005 which examined the foul and storm water drainage systems. The GDSDS outlined policies and future requirements of the region for foul and storm water drainage for the medium to long term. One of the key strategy recommendations of the GDSDS is the development of a regional wastewater treatment plant on the Donabate and Portrane peninsula, along with the development of an orbital sewer to transport wastewater to the regional plant. A Strategic Environmental Assessment (SEA) on the GDSDS Strategy was completed in 2008, with Fingal County Council as the lead authority
- Flooding; the report of the Flood Policy Review Group (OPW), recommendations from the EU Funded Strategies and Actions for Flood Emergency and Risk Management (SAFER) Project and the Dublin Coastal Flooding Protection Project (DCFPP) completed in 2008 and the Catchment Flood Risk Assessment and Management Studies (CFRAMS) being carried out for the Dodder and Fingal-East Meath area and the INTERREG IVB Flood Resilien Cities (FRC) Project addressing the pluvial flooding challenge.
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 6 REV F02 Figure 1.4- Eastern River Basin District
- Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 7 REV F02 1.3 RELEVANT LEGISLATION The key legislative provisions that specifically relate to water services strategic planning are as follows;
- The Water Services Act (Act No. 30 of 2007): Sections 36, 37, 38 and 77 of the Act legislate for the preparation, development, adoption, implementation and continuing review of water services strategic plans
- The Water Framework Directive (2000/60/EC): established a framework for the protection of all waters and their dependant wildlife/habitats under one piece of environmental legislation
- The Planning and Development Act (Act No. 30 of 2000): is a major update and consolidation of planning and development legislation, which provides for a proper planning and sustainable development
- Strategic Environmental Assessment Directive (2001/42/EC): requires that the environmental consequences of certain plans and programmes are identified and assessed during their preparation and before their adoption. Such plans and programmes are those that are likely to have significant environmental effects. The relevant arising national legislation that impacts on water services strategic plans is the European Communities (Environmental Assessment of Certain Plans and Programmes) Regulations, 2004 (S.I. No. 435 of 2004)
- The EU Floods Directive (2007/60/EC): This Directive requires Member States to assess if all water courses and coast lines are at risk from flooding, to map the flood extent and assets and humans at risk in these areas and to take adequate and coordinated measures to reduce this flood risk.
Figure 1.5 outlines all the relevant legislation provisions at EU and National level that also impact on water services planning in their requirements that have to be taken into account. Figure 1.5 Relevant Legislation Water Services Strategic Plans Main Legislation Other Relevant Legislation Water Services Act 2007 Water Framework Directive Planning & Development Act 2000 Strategic Environmental Assessment Shellfish Diirective Groundwater Directive Urban Ww Treatment Directive Shellfish Diirective Groundwater Directive Urban Ww Treatment Directive Shellfish Directive Groundwater Directive Urban Ww Treatment Directive Nitrates Directive Bio Diversity Directives Drinking Water Directive Bathing Water Directive Freshwater Fish Directive Water Pollution Acts & Regs Waste Management Acts Phosphorous Regulations
- Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 8 REV F02 Executive Summary Strategic Plan Support Data & Documentation Technical Reports 1.4 WATER SERVICES STRATEGIC PLAN – REPORTS The Water Services Strategic Plan (WSSP) is covered in the following hierarchy of reports;
- High Level Executive Summary; summary statement for regional adoption and national planning
- Dublin Region Local Authorities Water Services Strategic Plan (this document)- Detailed plan for management purposes by local authorities
- Water Services Strategic Plan – Technical Background Document; compiled from the existing technical reports available for the region, together with review and input from the individual Local Authority organisations.
- Support Data & DocumentationGuidance on the Preparation of WSSPs 1.5 SCOPE OF WATER SERVICES STRATEGIC PLAN In October 2008, Guidance on the Preparation of WSSPs was published by the Water Services Network Training Group (WSNTG) and the Department of the Environment, Heritage and Local Government (DEHLG). For each of the three disciplines, water supply, drainage and flooding, the WSSP is developed under a number of headings that correspond to the Guidance areas given, as follows:-
- Outline Service Standards and Levels of Service
- Strategic Measures
- Plan Implementation and Delivery. These issues are addressed in the WSSP by reference to available reports and system information. A key requirement of the WSSP would be for monitoring and reporting on system performance, condition of the assets and security of the service at each review of the WSSP. In this way, the assumptions would gradually become more robust, the investment needs would be more accurately defined and investments prioritised and overall service standards improved.
- National Plans and Strategies: Including the National Development Plan and the National Spatial Strategy
- Regional Plans and Strategies: Including the Regional Planning Guidelines (RPGs) and Integrated Planning Frameworks
- Local Plans and Strategies: Development Plans. This DR-WSSP details the current City Plans and projects and is based on the Assessment of Needs Report adopted by Dublin City Council following public consultation. This infrastructure is necessary to provide for development of Dublin City as set out in the Development Plan and this document will be incorporated into the SEA being carried out for the City Development Plan. As soon as the relevant sections of the Water Services Act 2007 are enacted to prepare a Water Services Strategic Plan a further SEA will be carried out as required for any additional elements not included in this current plan.
- 1.6.2 Water and Environmental Quality Plans The relevant plans include:
- Water Quality Management Plans
- River Basin District Management Plans and associated Programmes of Measures. 1.6.3 Waste Management Plans Regard has to be given to the relevant local authority Waste Management Plans and their associated Sludge Management Plans.
- Quality; to meet all of the requirements set out in National and EU Standards for wholesome safe drinking water
- Quantity; To provide sufficient water to meet domestic and non-domestic requirements, including allowance for peak demand at present and into the future
- Sustainability; To be environmentally sustainable such that demands can be met without compromising “good” water quality of sources while minimising general environmental impact.
2.2 WATER SUPPLY - LEVELS OF SERVICE 2.2.1 Statutory, Customer and Other Levels of Service The principal legislation in Ireland applicable to the delivery of safe drinking water is the European Communities (Drinking Water) (No. 2) Regulations 2007 - SI No. 278 of 2007. The principal compliances are that:-
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- Water supplied is wholesome and clean in that it is free from any micro-organisms and parasites and from any substance in concentrations that constitute a potential danger to human health
- It meets the microbiological and chemical water quality parametric value standards set out in the Schedule to the Regulations
- Parameters are to be analysed and minimum frequency of check and audit monitoring for each supply to be carried out in accordance with provisions in the Schedule to the Regulations.
- While the provision of clean and wholesome water is assured through legislative requirements, customers also expect a continuous supply at adequate pressures and expect prompt response to supply interruptions and queries. To ensure customer satisfaction, the following core customer services standards are identified in the WSSP:-
- Supply Pressure
- Supply Interruptions. 2.2.2 Water Supply - Levels of Service In developing the WSSP, consideration has been given to current service standards and to good practice levels of service by reference to international experience. These standards include fundamental requirements for delivery of quantity and quality but also include reliability of supply, response time to customer complaints or operational contingency.
- The following service standards have been considered in the WSSP together with the levels of service to be achieved:
- Water Quality; Monitoring indicates that the minimum statutory water quality standards are generally complied with in the supply. The WSSP requires Local Authorities to aim for recommended Guideline Standards set out in the Regulations, representing good practice operating standards, which provide an acceptable margin against failure of mandatory standards
- Capacity; The WSSP envisages target capacity standards to cater for normal operational and peak demands. This includes variation over a 24 hour day (morning and afternoon peaks), seasonal variations and provision for development. As far as practicable, the system should also meet fire flow requirements while maintaining a basic capacity for average demand
- Supply Pressure; In general, the WSSP targets a minimum pressure at the supply pipe of 15 metres residual head. It also provides that negative pressures should not occur under peak conditions as a protection against groundwater entering the network
- Supply Interruptions; Burst rate data is maintained for the network together with other unplanned interruptions to supply. The age of the network means that a guaranteed minimum frequency of interruptions would be difficult to achieve in the short term. However, Local Authorities are using burst rate data to target mains for rehabilitation and endeavour to provide a minimum response time and maximum outage period, in response to contingencies causing supply failure. Burst data should be maintained by all Local Authorities in order to adequately manage supply interruptions.
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 12 REV F02 These are the basic service standards targeted by the WSSP. Local Authorities also endeavour to meet good practice standards in terms of response to consumer complaints, advice to consumers on water conservation and demand management and advice to householders where chronic service pipe leakage is identified. The information systems in place across the Dublin Region should be used to evaluate service performance against these standards on an ongoing basis as demand increases and the system evolves. The strategic planning function should analyse and evaluate this performance in the formulation of strategic measures to be implemented.2.3 WATER SUPPLY STRATEGIC PLAN - OBJECTIVES Delivery of water to the levels of service identified will require that a number of objectives are satisfied in respect of the following:
- Water Quality Management (protection of raw water sources)
- Sustainable availability of adequate quantity
- Management of Water Supply Assets
- System Resilience and Operational Flexibility. 2.3.1 Quality Objectives The management of water quality, for the purposes of meeting drinking water quality standards in a sustainable manner, requires in the first instance that a holistic catchment based management approach is taken to protecting water resources, minimising risk of pollution and enforcing appropriate planning control of development. This requires a coordinated approach between the different local authorities given that the local authority managing the drinking water facility has little or no control over the catchment providing the raw water source. This requires that the concept of ‘source to tap’ water quality management is delivered in terms of:
- Best practice water resource management of the catchments as the primary means of protecting drinking water quality and reducing risk to public health
- Effective treatment of drinking water at each of the region’s drinking water production facilities by expanding and operating the facilities in accordance with best practice. This requires: o Liffey works at Ballymore Eustace; To complete the upgrading of this plant to achieve sustainable output of 318Ml/day (at construction stage) o Liffey works – Leixlip; To upgrade this plant to produce a sustainable 215Ml/day (works at tender stage) o Vartry works at Roundwood; To complete the refurbishment and maintain high-quality operation of these works for the maximum sustainable output of the Vartry source (80Ml/day)
- Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 13 REV F02 o Dodder works – Bohernabreena; To complete the refurbishment of these works and to maintain satisfactory operation for their maximum sustainable output (18Ml/day) o Groundwater sources; To continue to develop and protect groundwater potential in Fingal and Kildare, including monitoring of water quality and water treatment
- Distribution System; To protect water quality in distribution by an extensive ongoing monitoring programme and gradual reduction in risk factors in the supply system, in particular: o Eliminating uncovered storage in the supply through the provision of covered reservoirs at Stillorgan and Ballyboden o Monitoring pressure and avoiding as far as possible low service pressures, particularly where there is significant leakage risk o Gradual rehabilitation of old cast-iron mains, lead service pipes and antique Victorian mains, prioritising areas where monitoring indicates a risk of pollution to the water, elevated lead or iron concentrations.
- Water Safety Plans; in accordance with the World Health Organisation, will be developed. 2.3.2 Capacity Objectives The provisions of sustainable quantities of water for present and future needs will be delivered through the following planned objectives:
- Promoting maximum demand management and leakage reduction including pressure management, leak detection/repairs and priority mains replacement, allied to practical measures to promote demand reduction by consumers
- Completion of upgrading of existing plants to maximise the sustainable yield from existing sources. These works are in tandem with the upgrading required to ensure satisfactory water quality
- Strengthening of the distribution network including adequate storage where necessary, to ensure that adequate capacity can be delivered to all points in the network, including provision for development needs in accordance with the Local Authority Development Plans
- Identification and advance planning for new water supply resources for the Dublin Region to ensure that the medium-to-long term needs of the region can be provided for, consistent with the National Spatial Strategy and the Water Framework Directive
- To maintain accurate and up-to-date records of system assets and performance, covering the necessary information required to measure services standards and to identify deficiencies
- To maintain a programme of asset improvements sufficient to ensure the continued satisfactory performance including treatment plants, storage reservoirs, trunk and delivery mains and public supply pipes
- To maintain and update Regional GIS, Regional Telemetry and Regional Water Models to ensure most up to date data is used
- To provide for effective asset management of water supply infrastructure to include maintaining up to date information systems (GIS watermains system records) and system models capable of evaluating capacity and performance. To utilise these systems to develop asset management plans to maintain satisfactory performance of the assets
- To maintain and upgrade the Regional Telemetry System, facilitating better management and operation of assets.
- 2.3.4 Resilient Supply and Operational Flexibility Objectives The DR-WSSP aims to achieve a level of redundancy within the water supply system whereby an adequate level of resilience exists to cope with normal operational contingencies. This will be addressed through:
- Adequacy of treatment capacity to cater for water source contamination or treatment plant breakdown.
- Adequacy of treated water and supply side storage to protect against short term interruptions to supply (system failure, pump or treatment breakdown) and to meet short term peak demands on the system.
- To be capable of meeting reasonable requirements for fireflows throughout the network, taking account of the nature of development and local fire risk categories and the need to maintain water supply to customers. 2.4 WATER SUPPLY STRATEGIC PLAN – DEMAND Predicting growth in the demand for water services is based on how demographic, economic and social factors change in the forthcoming years.
- Review of all relevant reports
- Analysis of trends over the 1996 to 2007 period
- Local Authority Consultations.
- The total demand is arrived at by consideration of a number of sub-components and preparing projections for each to arrive at an overall total. The demand sub-components are as follows:
- Domestic Consumption
- Non Domestic Consumption
- Customer Side Leakage
- Distribution Network Leakage
- Headroom (peak/security of supply/contingency/climate change). Growth in water demand is primarily driven by population increases which result directly in increased personal consumption and also indirectly in increased industrial / commercial consumption. Economic growth rates, leakage management performance and water conservation performance are also contributory factors in demand growth. Average demand in the Dublin Region is expected to increase from approx 540Mld (2008) to 800Mld (2031). Figure 2.1 summaries demand growth and the Dublin Regions future needs.
Figure 2.1: Future Need Demand Review 450 500 550 600 650 700 750 800 850 2003 2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 Year Ml/d Average Demand Growth Sustainable Production from Existing Source Planned Sustainable Production Average Demand New Source Required Demand Projections Kildare (Barrow)
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 16 REV F02 Demand figures have been revisited due to the current economic slowdown and the possible effects on population growth. The overall trend in the forecasting is not thought to be significant.
However it could result in the timeframe for implementing the new water source being extended by one or two years. 2.5 WATER SUPPLY - STRATEGIC MEASURES 2.5.1 Asset Assessment and Options In order to plan for the delivery of a water supply, water services authorities shall identify when infrastructure has to be renewed, replaced or upgraded to meet existing and future customer demands to the levels of service outlined previously. Asset capacity assessment needs can then be carried out, i.e. assessing the potable water capacity and any shortfalls in, for example, the:- o Source and intake o Raw water mains o Treatment plants o Pumping stations o Trunk/rising mains o Storage reservoirs In addition to capacity shortfalls, future changes to legislation relating to water supply (eg.
more stringent drinking water regulations) may generate other shortfalls. Planning for future legislation is difficult to take account of until such time as the legislation is enacted, whereas higher levels of customer service expectation can be dealt with through review of the WSSP. In the case of the Dublin Region, the WSSP is prepared having regard to the aforementioned Greater Dublin Water Supply Strategic Study (GDWSSS 1996 and 2000 Review), including revised assessments carried out in 2006 in the context of the ongoing Water Supply Project – Dublin Region and other technical studies, detailing the status and priority requirements for water supply across the region.
- The options available to deal with asset capacity shortfalls and to deliver the required capacity are summarised as follows:-
- Adjust current operational practice of the existing asset
- Rehabilitate or renew the asset
- Upgrade or replace the existing asset
- Augment the existing capacity to the required level. A more detailed methodology on the assessment of assets and identifying options, to solve emerging shortfalls is given in section 4 of the Guidance on the Preparation of Water Services Strategic Plans, WSNTG and DEHLG, October 2008.
- Effective monitoring and management of water supply operations to verify compliance with the specified standards of service and progress towards achieving overall objectives of the WSSP
- Promotion of demand management to encourage best practice water management in new development and optimum water conservation among existing domestic and non-domestic users. This involves the provision of information and appropriate technical assistance for consumers, based on best practice. Pilot projects shall be promoted to target grey water re-use, use of water saving devices and rainwater recovery reducing water demand by consumers. Water Conservation Bye-Laws are in place in Dublin City Council, Fingal County Council and South Dublin County Council
- Maintenance and where necessary upgrading of water conservation and leakage control systems and resources towards achievement of the medium-term goal of overall regional water losses of 25% (of water into supply) and long-term 20 year goal (from now) of achieving a 20% maximum rate of losses across the region
- Promotion of cost effective management of all aspects of the water supply service, from source to tap, through appropriate input to the Development Planning Process and the River Basin Management Plans (RBMPs), a representative sampling and analytical programme, constant review and where appropriate, improvements in the management and resourcing of water services
- Maintain and upgrade the existing Regional Telemetry, GIS and Network Modelling Systems.
- 2.5.3 Water Services Capital Investment – Strategic Measures Measures involving capital investment are required in accordance with current plans and programmes. These include:
- Current and planned projects to upgrade water abstraction and treatment, upgrading of storage, transmission and distribution systems to meet short and medium term supply needs. This includes projects to upgrade existing treatment, covered reservoir and new reservoir storage
- Major investment in water mains renewal (€108 million in current contracts) focussed on leakage reduction as a priority using the most cost-effective means to upgrade leaking pipes, optimise supply pressures and reduce unnecessary water use. There comes a point where reducing leakage below a certain level (approx 20%) is not economically viable for networks of this nature – this is known as the “economic level of leakage” below which increasing levels of expenditures are required for ever decreasing leakage reductions
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- Upgrading of Regional Telemetry, GIS and Network Modelling Systems to keep them in line with modern standards. In addition to delivering this programme of works targeted at short to medium term needs, the Dublin Region Water Services Authorities will expedite the planning of new major water resources for the Dublin Region to meet the long term needs (20 to 25 years and beyond). This involves technical, environmental and socio-economic assessment of long terms strategic options including possible abstractions from the River Shannon, in conjunction with dry weather storage options, sea water abstraction and treatment by desalination and/or measures having regard to development requirements and climate change. These options are currently being examined through Strategic Environmental Assessment (SEA).
- 2.6 WATER SUPPLY – WSSP IMPLEMENTATION & INVESTMENT PROGRAMME The delivery of the objectives of the DR-WSSP requires a coordinated approach by the Dublin Region Water Services Authorities. This is achieved through strategic management and technical committees, coordinating delivery of capital and operational programmes, subject to the overall approval of the Department of the Environment, Heritage and Local Government (DEHLG). This includes:
- Integrated laboratory analysis, flow and pressure measurement and asset management information systems on behalf of the Authorities in the Region
- Delivery of a capital programme of works estimated to cost approx €500 million during the lifetime of the WSSP, covering the investment needs for the short to medium term together with essential planning of long term strategic measures required to meet the needs beyond the period of the WSSP.
More detailed information on capital expenditure for Water Services within the four Dublin Local Authorities (Dublin City Council, Dun Laoghaire-Rathdown, Fingal and South Dublin County Councils) is contained in Section 5 of this WSSP.
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 19 REV F02 3 DRAINAGE 3.1 STRATEGIC DRAINAGE PLAN - VISION The vision for drainage services for the Dublin Region is to provide adequate drainage collection and treatment facilities to meet the present and future demands, while ensuring and maintaining “good status” of all receiving waters in the Dublin Region into the future.
This is consistent with the objectives of the Water Framework Directive and requires that the collection, transport and disposal of both foul and stormwater drainage flows are managed effectively to achieve this purpose.
3.2 STRATEGIC DRAINAGE PLAN - LEVELS OF SERVICE 3.2.1 Statutory, Customer and Other Levels of Service The principal legislation in Ireland applicable to discharge standards for wastewater schemes is the Waste Water Discharge (Authorisation) Regulations 2007 – S.I. No. 684 of 2007. Also applicable are any requirements included in the Programme of Measures within the River Basin Management Plan for the River Basin to which the waste water scheme discharges – arising from the EU Water Framework Directive. The compliance requirements will vary depending on the overall impact on, and the designation of, the water body and the specific requirements of the licensing authority - the Environmental Protection Agency (EPA).
- While the provision is made for the environment with regard to allowable waste water discharges through legislative requirements, customers also expect prompt response to (for example) sewer flooding, environmental concerns and queries. To ensure customer satisfaction, the following core customer services standards are identified in the WSSP:-
- Waste Water Treatment Capacity
- Asset Condition
- Sewer Network Capacity/Flooding Risk
- Sewer Infiltration
- Overflows to Receiving Waters 3.2.2 Foul, Combined and Stormwater Drainage The existing drainage infrastructure comprises foul sewerage infrastructure (Figure 3.1 and Figure 3.2) including pipe network, pumping stations, treatment plants and overflow structures which relieve overloading in times of heavy rainfall.
In older areas, combined sewers collect both stormwater and foul flows in a common pipe and rely on combined sewer overflows (CSO’s) to divert excess flows to receiving rivers and streams when the
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 20 REV F02 downstream capacity of the pipe system is exceeded. Where such systems have become overloaded, there is a potential for pollution at CSO’s. At treatment plants, foul flows are treated having regard to prescribed effluent standards, while additional stormwater flows due to rainfall in the first instance overflow to storage for later treatment or when they exceed the storage capacity discharge directly to receiving waters.
Stormwater drainage provides for the collection of stormwater flows primarily from paved areas (roofs, roadways, paths etc) and these are generally conveyed to streams, rivers or coastal waters. Such systems have the potential to collect significant polluting matter which, when discharged, can cause environmental degradation in the receiving water environment.3.2.3 Foul Sewerage Systems - Levels of Service Detailed studies of the existing Dublin region foul sewerage systems have highlighted a number of difficulties in terms of service standards. These include:
- Quality; all existing treatment plants are undergoing or will require upgrading to provide adequate capacity for medium term development needs. While most plants are operating satisfactorily, there is generally a capacity shortfall for projected short term needs and in some instances tighter effluent standards are required to meet water quality objectives, for example at Osberstown (Naas). In addition, excessive overflows are occurring in the combined sewer systems (city and town centres and older urban areas) which result in occasional pollution of the receiving environment
- Capacity; the foul sewer network modelling has indicated significant surcharge and localised flood risk on a number of trunk sewers. When additional development is considered in the models, additional flood risk potential has been identified, generally associated with rainfall events and associated runoff to the sewer system. In addition, most of the treatment plants will require capacity upgrading for the additional volumes of sewage arriving at the works, in addition to treatment of organic and nutrient loadings
- Asset Condition; sewer surveys have identified areas of operational deficiency in the network in terms of; - Limited sections of sewers and culverts which are considered structurally deficient. These can be verified by CCTV surveys and analysis - Localised blockages and accumulation of sediment debris in foul sewers as identified by CCTV and hydraulic surveys is prevalent in many areas of the network and reflects unsatisfactory pipe gradients, artificial obstructions or inadequate maintenance. A continuing programme of CCTV surveys is required in order to maintain up to date asset condition records.
- Level of service standards have been identified in the GDSDS studies and form the basis of this Water Services Strategic Plan for foul drainage systems. Key levels of services criteria are:
- Wastewater discharge standards to comply with the requirements of the Water Framework Directive (WFD) and the specific requirements of the licensing authorities (EPA)
- Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 21 REV F02
- All new non domestic discharges to the foul sewer network to be pre-treated where necessary to characteristics similar to or less than normal domestic sewage
- For overflows to the receiving water, standards are required to be site specific and involve the following criteria: - to provide for a minimum retained flow in the foul sewer to ensure that any discharges are sufficiently diluted - to provide a minimum standard of screening to prevent an aesthetic nuisance (typically 6mm) - to provide a maximum predicted frequency of spill appropriate to the receiving waters (for example, 3 times in a bathing season for bathing waters) - to provide for appropriate limitations on spill volume and associated organic and nutrient loadings for discharges to sensitive waters
- Flooding risk from foul or combined sewers should be extremely low, not less than once in 20 years for onstreet flooding and once in 30 years for property flooding
- Maintenance of sewerage systems to avoid excessive silt and debris retention, avoid stagnant flows and provide for acceptable health and safety conditions for maintenance
- For pumping stations, to ensure appropriate standby equipment, ensure adequate wet well capacity, control and automation to protect performance in the event of an item of plant failure and for emergency call-out response in appropriate circumstances.
The information systems in place across the Dublin region should be used to evaluate service performance against these standards on an ongoing basis as demand increases and the system evolves. The strategic planning function should analyse and evaluate this performance in the formulation of strategic measures to be implemented.
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 22 REV F02 Figure 3.1: Existing Foul Sewer Treatment WWTW
Dublin Region Water Services Strategic Plan - 2009 MDW0326Rp0003 23 REV F02 Figure 3.2: Foul/ Combined Sewer Systems
- As development extends, the rate of runoff from paved areas is generally much greater than from undeveloped lands with the result that downstream flows increase and flooding can occur. This phenomenon is evident throughout the network
- Storm drainage systems have often developed in an adhoc fashion, with the result that pipe and culvert sizes may be inadequate for the ultimate extent of the development. This can give rise to local obstructions and blockage risks which can increase flooding
- High intensity storm events following a dry spell result in suspension and transport of detritus and floating debris in pipes, culverts and channels. This gives rise to blockages particularly at screens or entrances to culverts and bridges, causing flooding. These historic stormwater systems convey significant polluting matter from streets and other pavements to the watercourses. As a result, all of the streams in the Dublin conurbation exhibit disimprovement of quality from undeveloped catchment to developed catchment. This is evident in: - sediment covering the stream bed, causing loss of ecology - limited ecological species in the water environment indicative of occasional pollution shock loadings. This is indicated by the quality “Q” rating system of the EPA whereby Q1 is highly polluted and Q5 is pristine. In general, urban streams receiving significant stormwater drainage discharges are Q2 or Q3 at best. These fall well short of the “good” water quality target set by the Water Framework Directive - As flows increase, it becomes necessary to upgrade the hydraulic capacity of stream channels with the result that they are frequently canalised or culverted, with complete loss of riparian ecology.
In respect of existing storm drainage systems, the criteria for flood risk management are similar to those applicable to foul sewer systems, namely a minimum of 1 in 20 year protection from street flooding and 1 in 30 year protection from property flooding. The modelling studies carried out in the GDSDS study demonstrated local areas at risk throughout the catchments. Site specific risk assessments are required at these locations to determine the likely risk to property and the corresponding need for relief measures. In all cases the design criteria should future proof for climate change and the latest predictions.
The storm sewerage system data is to be accommodated in the same regional information system (GIS) containing foul sewerage data. The WSSP supports a common database and strategic evaluation of this information to assess performance and determine priority measures to meet the objective service standards.
- To provide and maintain satisfactory drainage infrastructure having regard to new development. This requires that drainage system capacity is provided to meet future development needs while catering satisfactorily for existing load conditions
- To ensure that planning policies are adopted which are consistent with the WSSP. These policies provide for best practise design, management and operation of drainage services as developed in the Greater Dublin Strategic Drainage Study (GDSDS) and adopted in the Development Plans for the Dublin Region Local Authorities (Figure 3.3)
- To provide for effective wastewater treatment for present and future needs, to comply with requirements of the licensing authorities and in accordance with the water quality criteria set for the receiving waters. As part of this objective, to provide that new non domestic discharges (following appropriate treatment at source where necessary) should be at or below the standard equivalent to domestic sewage
- To provide for sustainable urban drainage systems (SuDs) for all future stormwater drainage for new development with the objective of ensuring that stormwater discharges from such developments correspond in respect of both quality and quantity with the equivalent values from the undeveloped greenfield site
- To provide for effective asset management of drainage infrastructure to include maintaining up to date information systems (GIS sewerage system records) and system models capable of evaluating capacity and performance. To utilise these systems to develop asset management plans to maintain satisfactory performance of the assets
- To maintain and upgrade the Regional Telementry System, facilitating better management and operation of assets.
Figure 3.3: Regional Policies –GDSDS Environmental Management of Receiving Waters Climate Change Rising Sea Water Levels New Development SuDS Existing Drainage Infrastructure Continuous Discharges Overflows Inflow / Infiltration / Exfiltration Basements At Risk from Sewer Flooding