Offaly County Development Plan 2014-2020
Strategic Flood Risk Assessment
(October 2014)
Offaly County Development Plan 2014-2020 Strategic Flood Risk Assessment
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Offaly County Development Plan 2014-2020 Strategic Flood Risk Assessment
1. Introduction
Flooding is a natural process that can happen at any time in a wide variety of locations. Flooding has significant impacts on human activities; it can threaten people’s lives, their property and the environment. Assets at risk can include housing, transport and public service infrastructure, commercial, industrial and agricultural enterprises. The health, social, economic and environmental impacts of flooding can be significant and have a wide community impact.
Understanding flood risk is a key step in managing the impacts of flooding. Spatial Planning has a significant role to play with respect to flood risk management, in particular in ensuring that future development needs avoid or minimise future increases in flood risk. The ‘Planning System and Flood Risk Management’ Guidelines for Planning Authorities issued in November 2009 reinforce the responsibility of Planning Authorities to ensure that flood risk is managed effectively and sustainably as an integral part of the planning process balancing socio-economic needs, environment, and infrastructure and flood risk. As part of the management of flood risk, the guidelines, published jointly by the Department of the Environment, Heritage and Local Government (DoEHLG) and the Office of Public Works (OPW) set out the requirement for Planning Authorities to undertake a Strategic Flood Risk Assessment (SFRA) examining the risks of flooding in order to aid in making informed and sound planning decisions such as the zoning of particular areas for development or the development of land for particular uses.
1.1 Purpose of Strategic Flood Risk Assessment
The Planning System and Flood Risk Management, Guidelines for Planning Authorities, 2009, issued by the DoEHLG and undertaken in conjunction with the OPW, requires Planning Authorities to prepare a SFRA. The primary purpose of the SFRA is to determine flood risk within a particular geographical area, in this instance, County Offaly and to support spatial planning decisions in relation to the zoning of particular areas or lands for development. Under the Guidelines the objectives of an SFRA is to:
• Provide for an improved understanding of flood risk • Provide an identification of areas of natural floodplain to be safeguarded • Produce a suitably detailed flood risk assessment drawing on existing data and apply the sequential approach to development in areas identified at risk of flooding. • Inform the application of the Justification Test • Define measures required to deal with flood risks to reduce the risks to an acceptable level while not increasing flood risk elsewhere, and • Produce guidance on mitigation measures on how surface water should be managed and appropriate criteria to be used in the review of site specific flood risk assessments.
Robust information on flood risk is essential to inform and frame policies relating to flooding issues to be contained within the Offaly County Development Plan 2014-2020. The SFRA should be read as a technical document which forms part of the evidence base for the Offaly County Development Plan 2014-2020.
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It should be noted the SFRA is an ever evolving document, which is to be reviewed and updated on a regular basis in the light of emerging information, flood data and an improved understanding of flood risk. This SFRA takes into account the latest flood risk information/data available from the OPW and national guidance available.
1.2 Legislative and Planning Context 1.2.1 Water Framework Directive
The EU Water Framework Directive (WFD) aims at improving our water environment. It applies to rivers, lakes, groundwater, estuaries and coastal waters. Member States must aim to achieve good status in all waters by 2015 and must ensure that status does not deteriorate in any waters. In addition, the WFD defines a planning, management and reporting system based upon River Basin Districts and International River Basin Districts.
1.2.2 EU Floods Directive
The EU Directive on the assessment and management of flood risks [2007/60/EC], often referred to as the ‘Floods’ Directive, is a framework directive that requires Member States to follow a certain process, namely:
• Undertake a Preliminary Flood Risk Assessment (PFRA), to identify areas of existing or foreseeable future potentially significant flood risk (referred to as ‘Areas for Further Assessment, or ‘AFA’s). • Prepare flood hazard and risk maps for the AFAs by 22 December 2013, and, • Prepare flood risk management plans by 22 December 2015, setting objectives for managing the flood risk within the AFAs and setting out a prioritised set of measures for achieving those objectives
The OPW is the national authority for the implementation of the EU Directive on the Assessment and Management of Flood Risks [2007/60/EC].
1.2.3 National Flood Policy1
The National Flood Policy provides for the following recommendations:
• A focus on managing flood risk, rather than relying only flood protection measures aimed at reducing flooding • Taking a catchment-based approach to assess and manage risks within the whole-catchment context • Being proactive in assessing and managing flood risks, including the preparation of flood maps and flood risk management plans.
These recommendations lead to the development and implementation of the National CFRAM Programme.
1 www.opw.ie
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1.2.3.1 CFRAM Programme2
CFRAM is Catchment Flood Risk Assessment and Management. The national CFRAM programme commenced in Ireland in 2011. The CFRAM Programme is central to the medium to long-term strategy for the reduction and management of flood risk in Ireland. The Programme delivers on core components of the National Flood Policy, adopted in 2004, and on the requirements of the EU Floods Directive.
The CFRAM Programme comprises three phases:
• The Preliminary Flood Risk Assessment (PFRA): 2011 • The CFRAM Studies and parallel activities: 2011-2015 • Implementation and Review: 2016 onwards
The Programme provides for three main consultative stages:
• 2011 Preliminary Flood Risk Assessments • 2013 Flood Hazard Mapping • 2015 Flood Risk Management Plans.
Currently, in line with the EU Floods Directive, the National CFRAM Programme is underway, with CFRAM studies being carried out across seven river basin districts in Ireland. County Offaly lies across three river basin districts; Eastern, Shannon and South Eastern. More information on the CFRAM programme is available on www.cfram.ie.
2 www.opw.ie
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Map 1.1: River Basin Districts and County Offaly.
1.2.3.2 PFRA
The National Preliminary Flood Risk Assessment (PFRA) is a requirement of the EU ‘Floods’ Directive. The objective of the PFRA is to identify areas where the risks associated with flooding might be significant (referred to as Areas for Further Assessment, or ‘AFAs’). This has been undertaken the final designation list of areas of further assessment has been published since March 2012. The ‘AFAs’ are where more detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk, and, where the significance of the risk is confirmed, to develop where possible measures to manage and reduce the risk. The more detailed assessment, which will focus on the AFAs, will be undertaken through Catchment Flood Risk Assessment and Management (CFRAM) Studies for release in 2015.
1.2.4 The Planning System and Flood Risk Management, Guidelines for Planning Authorities.
The DoEHLG in conjunction with the OPW published guidelines for Planning Authorities in November 2009 entitled ‘The Planning System and Flood Risk Management’. The guidelines introduce comprehensive mechanisms for the incorporation of flood risk identification, assessment and management into the planning process. Planning Authorities (both elected members and officials) must implement these guidelines in ensuring that, where relevant, flood risk is a key consideration in preparing development plans and in the assessment of planning applications.
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Planning Authorities are required under section 28 of the Planning and Development Act 2000 (as amended) ‘to have regard to’ the guidelines in carrying out their planning function.
The core objectives of the guidelines are to:
• Avoid inappropriate development in areas at risk of flooding; • Avoid new developments increasing flood risk elsewhere, including that which may arise from surface water run-off; • Ensure effective management of residual risks for development permitted in floodplains; • Avoid unnecessary restriction of national, regional or local economic and social growth; • Improve the understanding of flood risk among relevant stakeholders; and • Ensure that the requirements of EU and national law in relation to the natural environment and nature conservation are complied with at all stages of flood risk management.
The guidelines contain alot of information relevant to the how the SFRA will be an informative policy framing document, the premise of which will be taken from the guidelines, transposed into the SFRA and enable it to act as a guidance document to inform decision making on land use zoning and general flood risk issues where required and relevant. In this regard, the provisions of the guidelines will be examined in further detail in section 3 of this SFRA.
1.3 Disclaimer
In order to comply with the requirements of The Planning System and Flood Risk Management - Guidelines for Planning Authorities, and of the Floods Directive 2007 60/EC it must be acknowledged that the appraisal of flood risk is an evolving process as it is based on emerging data on flood events. The assessment and mapping of areas at risk of flooding awaits the publication both of Preliminary Flood Risk Assessments [PFRAs] and Catchment-based Flood Risk Assessment and Management Plans [CFRAMs]. As a consequence, the Strategic Flood Risk Assessment for County Offaly is based on the most current available information from the OPW who are charged with responsibility in this area.
Accordingly, all information in relation to flood risk is provided for general policy guidance and may be updated in respect of emerging new data and analysis. Owners/occupiers, developers and any other interested body are advised to take all reasonable measures to assess the flooding vulnerability or risk of lands in which they have or may have an interest prior to making planning or development decisions.
The aim of this Stage 1 SFRA is to provide an appraisal of all sources of flooding within County Offaly and to set out a number of approaches in the plan making process to avoid, reduce and manage flood risk as part of a wider objective to ensure the protection of property, people and infrastructure. The SFRA does not contain advice for existing occupiers who currently live in areas at risk of flooding or those that may experience flooding.
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2. County Offaly in Context
2.1 Introduction This section examines the context of County Offaly including the nature of river catchments, population and settlement patterns and the number and location of vulnerable receptors. This section provides an overview of County Offaly on which the impact on flooding will be discussed and determined in the later sections of this SFRA.
2.2 Location and Physical Geography County Offaly is located within the midlands of Ireland and has an area of approximately 2,000 km2 (c. 800 sq. miles). Offaly borders seven counties which are Galway, Roscommon, Tipperary, Laois, Westmeath, Kildare and Meath.
Map 2.1: Location of County Offaly in Context.
The Slieve Bloom Mountains are located in the southern part of the County on the border with Laois. The floodplain of the River Shannon occupies the north western part of the County. There are a number of main watercourses located in the County. The River Camcor runs through the town of Birr, the River Brosna runs across the county from Lough Owel in Westmeath to Shannon Harbour in the west of the
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County and the Silver River runs through several Offaly towns before joining the River Brosna near Ferbane Town. The Grand Canal runs across the County from Edenderry in the north east to Shannon Harbour before joining the River Shannon in the west. Offaly contains many small lakes from Lough Boora to Pallas Lake.
Offaly largely comprises a flat landscape. There are many large bogs in Offaly which are spread out across the county. Offaly consists of approximately 42,000 hectares of peatlands which accounts for approximately 21% of the County’s total land area.
Offaly contains approximately 22,000 hectares of forest and woodland. This amounts to over 10% of the land area of the County and includes woodlands within the Slieve Blooms and Lough Boora Parklands. Approximately 75% of the forested area comprises coniferous planting.
2.3 River Catchment Offaly is bordered by the counties (seven) listed above and therefore does not have any coastline. The main rivers are distributed throughout the county as per map 2.2 and are listed below in Table 2.1. The Rivers listed are exclusive of smaller tributaries and drains which in the own right can be fundamental to flood risk issues.
Map 2.2: Main Rivers flowing through County Offaly
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Table 2.1: Main Rivers flowing through County Offaly River Length in Offaly (KM) Figile 35 Esker (Stream) 12 Yellow 15. 4 Castlejordan 19.8 Tullamore 22.0 Enaghan (Stream) 9.2 Clodiagh 38.5 Cushina 21.1 Daingean 24.4 Black [Ballyboy] 11.86 Silver [Kilcormac] 35.7 Pollagh Stream [Brosna] 9.0 Brosna 71.8 Silver [Tullamore] 26.0 Durrow Abbey (Stream) 58.7 Blackwater 15.5 [Shannonbridge] Little [Cloghan] 13.4 Boora 6.6 Breaghmore 13.8 Clareen Stream 10.6 Little Brosna 60. Rock [Birr] 11.4 Bunnow 14.9 Golden Grove Stream 8.0
Camcor 22.5 Shannon* 39 Barrow* 20
*These rivers flow adjacent to County Offaly.
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2.4 People, Property and Infrastructure The population of County Offaly is 76,687 according to the census of population 2011. The main towns and aggregate villages, Sráids and Open Countryside in County Offaly with their respective population are shown below in Table 2.2 and their location can be viewed on the corresponding map 2.3.
Table 2.2 Population of County Offaly by Town, aggregate Villages, Sráids and Open Countryside
Town/village Census of Population 2011 Tullamore 14, 361 Birr 4,428 Edenderry 6,977 Portarlington 1,678 Clara 3,894 Ferbane 1,165 Banagher 1,653 Daingean 1,037 Kilcormac 870 Villages (all) 8,639 Sráids and Open Countryside 31,988 Total 76,687
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Map 2:3 Settlement location in County Offaly
82% of the buildings in Offaly are listed in the An Post Geo-directory as being residential, 6.4 % are commercial and 11.4 % are dual purpose. There is one Regional Hospital located in Tullamore Town, 66 primary schools and 12 secondary schools in the County.
Essential road infrastructure includes the M7, N52, M6, and N80, which pass through Offaly. The Dublin to Galway and Westport/Ballina railway line crosses into Offaly from the south east through to the North West, with stations in Portarlington (to south east, on the Laois side), Tullamore and Clara.
2.5 Environment In May 1992, governments of the European Communities adopted legislation designed to protect the most seriously threatened habitats and species across Europe. This legislation is called the Habitats Directive and complements the Birds Directive adopted in 1979. These two directives are the basis of the creation of the Natura 2000 network of protected areas. Natura 2000 is an ecological network of protected areas. The Birds Directive requires the establishment of Special Protection Areas (SPAs) for birds. The Habitats Directive similarly requires Special Areas of Conservation (SACs) and Natural Heritage Areas (NHAs) to be designated for species other than birds, and for habitats. Together, SPAs, SACs and NHAs make up the Natura 2000 network of protected areas.
The following environmental designations are in place in County Offaly:
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Table 2.3: Special Areas of Conservation (SAC): Site Code Site Name 000216 River Shannon Callows 000412 Slieve Bloom Mountains 000566 All Saints Bog and Esker 000571 Charleville Wood 000572 Clara Bog 000575 Ferbane Bog 000576 Fin Lough 000580 Mongan Bog 000581 Moyclare Bog 000582 Raheenmore Bog 000585 Sharavogue Bog 000919 Ridge Mill, SW of Rapemills 000925 The Long Derries, Edenderry 001776 Pilgrim’s Road Esker 002147 Lisduff Fen 002162 River Barrow and River Nore 002236 Island Fen
Table 2.4: Natural Heritage Areas (NHA):
Site Code Site Name 000564 River Little Brosna Callows 000565 Clonydonnin Bog 000570 Black Castle Bog 000890 Cangort Bog 000921 Screggan Bog 002033 Daingean Bog 002355 Hawkswood Bog
Table 2.5: Special Protection Areas (SPA):
Site Code Site Name 004017 Mongan Bog 004086 Little Brosna River Callows 004096 Middle Shannon Callows 004103 All Saints Bog 004137 Dovegrove Callows 004160 Slieve Bloom Mountains
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2.6 Key Settlements County Offaly is located within the Midland Region and is guided by the Midland Regional Planning Guidelines (MRPGs) 2010-2022. The Offaly County Development Plan informed by the MRPGs is charged with identifying a hierarchy of settlements which are identified for growth. The settlement Hierarchy for County Offaly at present is outlined in Table 2.6.
Table 2.6: Settlement Hierarchy (as taken from the Offaly County Development 2009-2015 (as amended) and including extracts from the MRPGs).
Tier Settlement Settlement Defined Strategic Role Role Tier 1 Linked Tullamore Identified as a ‘driver’ for regional growth, the linked Gateway gateway is the focus for the bulk of target population for the period 2010-2022. Tier 2 Key Service Birr, Edenderry, Portarlington These towns are important drivers for local economies in Towns areas that are more remote from main population centres. Well established economic, administrative and social functions are provided within these areas. Tier 3 Service Towns Clara, Ferbane These towns perform important retail, residential, service and amenity functions for local and rural hinterlands. Many of these towns have experienced significant population growth over the last census period. Consolidation of growth is necessary and the provision of relevant physical and social infrastructure. Tier 4 Local Service Banagher, Daingean, Kilcormac These towns are more remote from linked gateway and Towns principal towns and perform important local level residential, retailing, social and leisure functions and provide appropriate local services to a wider rural hinterland. Tier 5 Villages Belmont, Ballinagar, Ballycumber, Villages are smaller settlements, many of which are very Bracknagh, Cloghan, Clonbullogue, attractive and rural in character. The level of services Cloneygowan, Coolderry, Crinkle, provided will vary between settlements and will depend Geashill, Killeigh, Kinnitty, on the surrounding rural hinterland. Residential Mucklagh, Moneygall, development in these settlements should be of Mountbolus, Pollagh / appropriate scale and density. Lemanaghan, Riverstown, Shannonbridge, Shannonharbour, Shinrone, Rahan, Rhode, Walsh Island. Tier 6 Sráids Ballinamere, Ballyboy, Ballyfore, Sráids are very small, embryonic rural settlements. Sráids Blueball, Boher, Boora (Leabeg), have a loose gathering of existing development mainly Brosna, Cadamstown, Clareen, housing but with some services. New development Clonfinlough, Croghan, Doon, should reflect this existing settlement pattern. Dunkerrin, Durrow, Fivealley, and Garryhinch, Horseleap, High Street, Killina, Killurin, Killyon,
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Lusmagh, Rath, Roscomroe, Tober. Open countryside comprises largely rural areas. The role Open of rural areas is to support the settlement strategy by Countryside ensuring that development in these areas does not compromise the integrity of defined urban and village roles by maintaining sustainable, rural level infrastructural demands.
This SFRA focuses on the settlements identified in the settlement hierarchy which may be subject to landuse zoning or targeted for development or growth. The SFRA aims to assist in the decision making process as to how best to deal with identified flood risk.
Within the Offaly County Development Plan there is a hierarchy of spatial plans. While the SFRA takes a cursory examination of all settlements within Offaly for the purposes of stage 1, it must be noted that further examination of flood risk in the context of land use zoning must be undertaken at each plan level for the individual settlements they address. Each plan is subject to review periodically and is subject to the requirement to deal with the issue of flood risk. The spatial plan hierarchy is as follows for Offaly:
Offaly County Development Plan
Tullamore Town and Environs Birr Town and Environs Portarlington Joint Development Plan Development Plan Local Area Plan Edenderry Local Area Plan 2010-2016 2010-2016 2012-2018 2011-2017
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3. The Planning System and Flood Risk Management Guidelines 2009
Chapter 1 outlines the core objectives of the guidelines but this section explores the guidelines in further detail as they gives guidance to Planning Authorities on how best to prepare an effective SFRA.
3.1 Planning Principles of Flood Risk Management
The guidelines outline key principles of flood risk management which are to:
Avoid development that will be at risk of flooding or that will increase the risk of flooding elsewhere where possible Substitute less vulnerable uses where avoidance is not possible and, Mitigate and manage the risk where avoidance and substitution are not possible.
The guidelines set out the principle that development should not be permitted in flood risk areas except where there are no alternative and appropriate sites availale in lower risk areas that are consistent with the objectives of proper planning and sustainable development.
3.2 Types and Causes of Flooding
The guidelines explain that flooding is a natural process that can happen at any time in a wide variety of locations, in different forms and thus presenting varying degress of difficulty to people, property and the environment. Climate change and its impact in relation to frequency, pattern and severity of flooding is recognised as becoming more uncertain and more damaging.
The guidelines recognise that there are two major causes of flooding i.e. • Coastal flooding – caused by higher sea levels resulting in sea overflowing onto land. • Inland flooding – caused by prolonged and/or intense rainfall.
The latter (Inland flooding), is experienced in County Offaly and presents in many forms including:
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Table 3.1: Types and Causes of Inland flooding Type Description Occurs when the amount of rainfall exceeds the Overland flow infiltration capacity of the ground to absorb it. The excess water flows overland, ponding in natural hollows and low-lying areas or behind obstructions.
Occurs when the capacity of a watercourse is exceeded River flooding or the channel is blocked or restricted, and excess water spills out from the channel onto adjacent low- lying areas (the floodplain). This is known or referred to as fluvial flooding. Occurs when flow entering a system, such as an urban storm water drainage system, exceeds its discharge capacity and the system becomes blocked, and / or cannot discharge due to a high water level in the Flooding from artificial drainage systems receiving watercourse. This mostly occurs as a rapid response to intense rainfall. Together with overland flow, it is often known as pluvial flooding. This is recognised as being a significant factor of flood risk as evidenced in recent summer events. Occurs when the level of water stored in the ground rises as a result of prolonged rainfall to meet the Groundwater flooding ground surface and flows out over it, i.e. when the capacity of this underground reservoir is exceeded. Occurs due to a combination of tidal and fluvial flows, i.e. interaction between rivers and the sea, with Esturial Flooding tidal levels being dominant in most cases which will prevent water flowing out to sea tending to increase water levels inland, which may flood over river banks.
3.2.1 Other sources of flooding stem from: (i) Failure of infrastructure designed to carry or store water, and (ii) Increase in flood risk as an outcome of new development: • Upstream – by restricting the capacity and conveyance function of the watercourse or floodplain, • Downstream - by decreasing the volume available for flood storage, altering flow routes, creating changes to the water channel all of which can increase the flow discharged to downstream locations and also be increasing run-off due to the introduction of surfaces with reduced permeability i.e. car parks, road surfaces etc.
In the guidelines, the probability of flooding is established through the identification of Flood zones which describe a High, Moderate or Low risk of flooding from fluvial or tidal sources. These are defined
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Offaly County Development Plan 2014-2020 Strategic Flood Risk Assessment geographical areas defined and used as a key tool in flood management. This is described in further detail in Table 3.2.
Table 3.2: Description of Flood Zones
Zone Risk Description The probability of flooding from rivers and the sea is highest (greater than 1% Flood Zone A High probability of flooding or 1 in 100 for river flooding or 0.5% or 1 in 200 for coastal flooding);
The probability of flooding from rivers and the sea is moderate (between 0.1% or 1 in 1000 and 1% or 1 in 100 for river Flood Zone B Moderate probability of flooding flooding and between 0.1% or 1 in 1000 year and 0.5% or 1 in 200 for coastal flooding);
The probability of flooding from rivers and the sea is low (less than 0.1% or 1 in Flood Zone C Low probability of flooding 1000 for both river and coastal flooding). Flood Zone C covers all areas of the plan which are not in zones A or B.
It is important to note that the flood zones as defined do not not take into consideration other sources of flooding such as groundwater or pluvial. This requires an assessment of risk arising from such sources.
The consequences of flooding depend on the hazards caused by flooding and the vulnerality of receptors i.e. nature of development, age structure of population integral to the development, mitigation measures etc.
On helping to define flood risk further, taking into account matters of probability and consequence, the guidelines have identified the planning implications for each of the Flood Zones A, B and C.
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Table 3.3: Flood Zones and implications for planning
Zone Inappropriate development Appropriate development
Most types of development would be Water compatible development such as considered inappropriate in this zone. docks, marinas, dockside activities that Development in this zone should be require a waterside location, amenity Zone A – High probability of flooding avoided and/or only considered in open space, outdoor sports and exceptional circumstances such as in recreation. City/Town Centres or in the case of essential infrastructure that cannot be provided elsewhere. Justification Test must be applied in such cases. Less vulnerable development such as retail, commercial and industrial uses, sites used for short term caravan and Highly vulnerable development such as camping and secondary strategic hospitals, residential care homes, Garda, transport and utilities, infrastructure and Fire and Ambulance stations, dwelling water compatible development might be houses and primary strategic transport considered appropriate in this zone. Less Zone B Moderate probability of and utilities infrastructure would be vulnerable development should only be flooding generally considered inappropriate at considered if adequate lands/sites are this location unless the justification test not available in Zone C and subject to a can be met. flood risk assessment to the appropriate level of detail to demonstrate that flood risk to/from the development can or will be managed adequately. Development in this zone is appropriate from a flood risk perspective subject to assessment of flood hazard from sources Zone C – Low Probability of flooding other than rivers or tidal and would need to meet the normal range of other proper planning and sustainable development considerations.
The Classification of Vulnerability of different types of development is outlined in the guidelines in Table 3.1. This classification table may provide clarity on development uses as defined by the guidelines under each of the vulnerability headings and should therefore be consulted at all times. Where a specific use is not explicitly stated another use of similar nature may be used in its place to determine vulnerability classification.
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3.3 Staged Approach
The guidelines recommend a staged approach to be adopted to ensure that only such an appraisal or assessment as is needed for the purposes of decision making at the various plan levels is undertaken. The stages include:
Stage 1: Flood risk Identification: To identify whether there may be any flooding or surface water management issues related to the area of the regional planning guidelines, development plans or local area plans (LAPs) or a proposed development site that may warrant further investigation at the appropriate lower level plan or planning application level. If the Planning Authority considers that there is potential flood risk issue, then stage 2 shall be entered into.
Stage 2: Initial flood risk assessment: to confirm sources of flooding that may affect a plan are or proposed development site, to appraise the adequacy of existing information and to scope the extent of the risk of flooding which may involve preparing indicative flood zone maps.
Stage 3: Detailed flood risk assessment: To assess flood risk issues in sufficient detail and to provide quantitaive appraisal of potential flood risk to a proposed or existing development or land to be zoned, of its potential impact on flood risk elsewhere and of the effectiveness of any proposed mitigation measures.
This staged approach is recommended for flood risk assessments at Regional, County and site-specific levels. Within this hierarchy of Regional, County and site-specific flood-risk assessments, a staged approach ensures that the level of information is appropriate to the scale and nature of the flood-risk issues and the location and type of development proposed, avoiding expensive flood modelling and development of mitigation measures where it is not necessary.
3.4 Sequential Approach
The sequential approach is the mechanism promoted in the guidelines to ensure that development, particularly new development is directed to areas at low risk of flooding. The sequential approach is recommended to be applied to all stages of the planning and development management process. Figure 3.2 sets out the broad philospohy underpinning the sequential approach to be applied in order to best manage flood risk.
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Figure 3.2: Broad philosophy underpinning the sequential approach in flood risk management:
Avoid
Preferable choose lower risk flood zones for new development
Substitute Ensure the type of development proposed is not especially vulnerable to adverse impacts of flooding
Justify Ensure that the development is being considered for strategic reasons
Mitigate Ensure flood risk is reduced to acceotable level
Proceed Only where justification test is passed. Ensure emergency planning measures are in place
Source: The Planning System and Flood Risk Management Guidelines (2009)
3.5 Justification Test
The Justification Test is designed to rigorously assess the appropriateness, or otherwise, of particular developments that, for various reasons, are being considered in areas of moderate or high flood risk. The test comprises two processes:
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• The Plan-Making Justification Test is relevant for the making and adopting of development plans where it is intended to zone or otherwise designate land which is at moderate of high risk of flooding. • The Development Management Justification Test is used at planning application stage where it is intended to develop land at moderate or high risk of flooding for uses or development vulnerable to flooding that would generally be inappropriate for that land.
Table 3.4: Matrix of vulnerability versus Flood Zone
Flood Zone A Flood Zone B Flood Zone C Highly vulnerable Justification Test Justification Test Appropriate development including essential infrastructure Less vulnerable Justification Test Appropriate Appropriate development Water compatible Appropriate Appropriate Appropriate development
3.6 SFRA and SEA
As detailed in the Planning System and Flood Risk Management Guidelines, the steps in the development plan process and its Strategic Environmental Assessment (SEA) need to be supported by appropriate analysis of flood risk. The SEA process addresses any likely significant effects on the environment and their amelioration, from the implementation of development plans through all stages of the plan-making process.
Stage 1 SFRA Flood Risk Identification is recommended to be carried out and integrated with the SEA process. Subsequent stages of flood risk assessment should also be integrated with SEA.
The SEA report will consider the environmental effects of the Development Plan, including flood management policies and recommendations. These will be assessed against environmental criteria for the plan area and the SEA will detail mitigation measures and future monitoring requirements.
A summary of the likely effects of the plan on the environment, through exposing new development and their occupants to potential flood risks and any adverse impacts as a result, will be addressed in the SEA process.
3.7 Key Outputs from the SFRA
The guidelines require a certain level of output (depending on number of stages examined) from SFRA documents which include: • To provide for an improved understanding of flood risk issues within the Development Plan and development management process, and to communicate this to a wide range of
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stakeholders; • To produce a suitably detailed flood risk assessment that supports the application of a sequential approach in key areas where there may be tension between development pressures and avoidance of flood risk; • To inform, where necessary, the application of the Justification Test; • To conclude whether measures to deal with flood risks to the area proposed for development can satisfactorily reduce the risks to an acceptable level while not increasing flood risk elsewhere, and • To produce guidance on mitigation measures, how surface water should be managed and appropriate criteria.
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4. Data Collection
4.1 Introduction
This section gives an overview of the data collection and the review process carried out as part of the SFRA. In collating the data sources it must be acknowledged that flooding can come from a variety of sources, including rivers, rainfall on the ground surface (surface water), rising groundwater, overwhelmed sewer and drainage systems and breached flood defenses. Therefore flood risk from each of these sources has to be collected and appraised. The resultant data findings are represented on the individual settlement maps in Appendix 1 of the SFRA. The identification of flood risk is the first step of the process. The initial appraisal will inform where and how to deal with future flood risk in compliance with National guidance on Flood Risk Management.
4.2 Approach to Data Gathering
Throughout the data collection and review process it has been critical to make best use of the significant amount of information which already exists with respect to flood risk.
Data available to this SFRA included:
• National Preliminary Flood Risk Assessment (PFRA) Study (undertaken by OPW). • Tullamore Flood Risk Assessment and Management Study (FRAM) 2008. • Portarlington Flood Risk and Management Strategy 2007. • Regional Flood Risk Appraisal (Midland Regional Planning Guidelines 2010-2022, Volume 3). • Alluvial Soil Maps (Source EPA). • Groundwater vulnerability maps (Geological Survey Ireland, GSI). • Historic Flood Records including photos, aerial photos and reports. • Historic Flood Outlines. • Benefiting Land Maps and Drainage Districts.
4.2.1 National Preliminary Flood Risk Assessment (PFRA)
The National Preliminary Flood Risk Assessment (PFRA) is a national screening exercise undertaken by the OPW, based on available and ready derivable information, to identify areas where there may be a significant risk associated with flooding. The PFRA is a broad scale assessment. The objective of the PFRA is to identify areas where the risks associated with flooding might be significant. Areas of further Assessment or AFAs are also identified and a more detailed assessment of such areas will be undertaken through Catchment Flood Risk Assessment and Management (CFRAM) Studies.
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The key approaches in undertaking the PFRA include:
Historical Analysis: Using information complied previously.
Predictive Analysis: Assessing areas that could be prone to flooding as determined by predictive techniques such as modeling, analysis or other calculations, and of the potential damage that could be caused by such flooding.
Consultation: Using local and expert knowledge of Local Authorities and other government departments and agencies to identify areas prone to flooding and the potential consequences that could arise. The PFRA study considered flooding from a number of sources; fluvial, tidal, pluvial and groundwater and prepared flood maps which are available to inform, in an overview capacity, the location and extent of flooding. The information contained within the PFRA maps cannot be taken definitively as further assessments will be undertaken. Nevertheless, these flood maps, with the broad level of information contained, assist in identifying flood risk of varying sources.
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Map 4.1 Predictive Flood Risk Assessment Zones in Offaly
4.2.2 Regional Flood Risk Appraisal (Midland Regional Planning Authority Guidelines, Vol 3)
The Midland Regional Planning Guidelines (MRPGs) 2010 – 2022, put forward the overall planning strategy for the Midland Region of Ireland. Volume 3 of the MRPGs contains a Regional Flood Risk Appraisal (RFRA), which sets out the key policy recommendations with regard to avoiding and managing flood risk in the Midland Region.
The RFRA lists the following datasets available to inform flood risk management in the Counties that make up the Midland Region and include (with particular relevance to County Offaly):
• OPW flood events mapping • OPW Arterial Drainage mapping • Mineral Alluvial Soil Mapping • Local Authority datasets.
Based on the available data, the RFRA identified the key towns in the Midlands Region that may be vulnerable to flooding. The RFRA identifies the following settlement areas in County Offaly that are vulnerable to flooding:
• Tullamore (Linked Gateway Town) • Portarlington (Key Service Town) • Birr (Key Service Town) • Edenderry (Key Service Town)
The RFRA identifies 5 strategic policies addressing Flood Risk at Regional Level comprising:
1. To implement the recommendations and provisions of the Planning Guidelines on the Planning System and Flood Risk Management. 2. Adopt a sequential approach to flood risk management in the making of development plans and local area plans to guide development away from areas that have already been identified as being at risk and areas that emerge as being at risk when flood risk maps have been prepared for the Region. 3. Local authorities within the Region shall fulfill their responsibilities under the Flood Directive and cooperate with the Office of Public Works in the development of any Catchment-based Flood Risk Management Plan as necessary. Recommendations and outputs arising from Flood Risk Management Plans will be incorporated into the lower-tier plans as relevant. 4. Local authorities within the Region shall undertake FRAs as appropriate in the preparation and Review of Development and Local Area Plans as set out in the Planning Guidelines on the Planning System and Flood Risk Management. 5. Development in areas at risk of flooding, particularly floodplains, shall be avoided by not providing for or permitting development in flood risk areas unless: it is fully justified that there are wider sustainability grounds for appropriate development; unless the flood risk can be reduced or managed to an acceptable level without increasing flood risk elsewhere; and, where possible, it reduces flood risk overall.
Offaly County Development Plan 2014-2020 Strategic Flood Risk Assessment
The RFRA notes that water-compatible developments such as docks and marinas, amenity open space, outdoor sports and recreation may be compatible in areas at high risk, while more vulnerable development should be directed towards areas of minimal or no flood risk.
4.2.3 Local Flood Studies
4.2.3.1 Tullamore Flood Risk Assessment and Management Study (FRAM) 2008.
The OPW undertook a Flood Risk Assessment and Management Study (FRAM) in and around Tullamore looking at part of the Tullamore Urban area as well as future development land located on the Tullamore River floodplain which is subject to flooding.
The study entailed a number of sequential steps including:
Hydrological and Hydraulic Assessment: providing for the estimate design of peak flood flows. Measures: To relieve flooding or mitigate against the impacts of floodplain development in Tullamore. Options: examined to offset both the risk to existing development and that arising from possible future development. Multi-criteria Analysis: Analysing potential options against defined criteria in order to select a preferred option.
The recommendations of the study deal with existing risk in addition to how best to deal with the potential future risk should development take place within the floodplain. In relation to existing risk, the OPW recommends a flood relief scheme which would entail protecting existing residential areas. The flood relief scheme has commenced. The main aim of this flood relief scheme is to protect the residential areas of Whitehall and Oaklee. These works protect existing developments in the area.
In relation to future risk, flood risk management policy must be adhered to in order to avoid development within the floodplain area. Should development take place in the floodplain, an appropriate sequence should be followed which is identified and elaborated upon in the study.
4.2.3.2 Portarlington Flood Risk and Management Strategy 2007.
This study, commissioned by Laois and Offaly County Councils, looked to evaluate and quantify flood risk in Portarlington. The study recommend a series of mitigation measures in the form of floodwalls, levees, embankments and attenuation areas at various locations through the centre of Portarlington along the banks of the River Barrow and the Blackstick Drain.
4.3 Soil and Groundwater National Soil maps are available from the EPA and Teagasc. These soil maps indicate locations of mineral alluvium deposits which are a good indicator of flood risk and this information was used in the RFRA. Based on the EPA Alluvium map, there are alluvium soils deposits mainly within the Brosna River and Tullamore River catchments, as well as the River Shannon catchment. In addition, there are also
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alluvium soils deposits within the Boyne catchment, the River Barrow catchment to the south east of County Offaly, the Camcor and the Silver River catchments also..
Map 4.2: Alluvium Soils (location) Offaly.
Source: gis.epa.ie
Groundwater maps are available from the Geological Survey of Ireland (GSI). These maps indicate a vulnerability index, based on a number of parameters including: • Sub-soils that overlie the groundwater; • Type of recharge - whether point or diffuse; • Thickness of the unsaturated zone through which the contaminant moves.
The more vulnerable the groundwater is to contamination (i.e. passage of contaminants down through the soil), the more chance there is of the groundwater rising to the surface and causing flooding. The GSI mapping indicates that much of the groundwater in Offaly is Low to Moderately vulnerable to contamination. The extremely and highly vulnerable areas are focused in the Slieve Bloom Mountain area to the south east of the County and in particular areas to the east of the County. Section 5.3 and Map 5.1 examine and identify the groundwater vulnerability classifications for County Offaly.
Although there are no flood records listing 'groundwater' as a source of flooding, it is often difficult to distinguish groundwater and surface water in the historical records.
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4.4 Historic Flood Records and outlines The OPW makes available information on past flooding events and recurring events for County Offaly. To date 117 such events are recorded across County Offaly. Information has been collated from a number of sources and relate to events of a recurring or extreme nature. Information comes in the form of a written description along with associated maps and photographs.
Offaly County Council also hold information on past flood events in a similar manner to the OPW. The sources for such information vary.
4.5 Benefiting Land Maps and Drainage Districts Benefiting Land Maps and Drainage Districts are useful to highlight areas where maintenance or drainage works have been undertaken or have been required in the past. Several hundred minor drainage improvement schemes, on localised stretches of river, were first established under the 1842 Arterial Drainage Act. Some of these schemes were then subsumed into Arterial Drainage Schemes under the 1945 Arterial Drainage Act, but circa 172 schemes remain standalone and are known as Drainage Districts (DD). Maintenance responsibilities, for drainage districts, remains with the local authorities while the OPW conduct a policing role.
Benefiting land maps were prepared to identify areas that would benefit from land drainage schemes and typically indicate low-lying land adjacent to rivers and streams. Drainage district maps, similar to the Benefiting Land Maps, were prepared with respect to the Land Commission Embankments and Drainage District Works that pre-dated the Arterial Drainage Schemes commenced in 1945.
Benefiting Lands and Drainage Districts have been identified on the SFRA maps included for each of the settlements examined in this SFRA.
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5. Flood Risk Appraisal in County Offaly
5.1 Overview This section identifies the predominant sources of flooding experienced in County Offaly. Further this section will also identify flood risk for individual settlements in County Offaly which are the focus of future development.
5.2 Historical Flood Records Records of past flooding in County Offaly are useful for providing background information. The OPW through the National Flood Hazard Mapping website (www.floodmaps.ie) makes available information on areas potentially at risk from flooding. This website provides information on numerous historical flood events that have affected Offaly. Such information has informed the RFRA also. Information is provided in the form of reports, photographs and newspaper articles. This information, along with details of the locations of more frequent and often recurring events, is also available.
To date in Offaly 117 flood events are recorded. Table 5.1 below is a snapshot of flood events as they are recorded and used for information for the purposes of data gathering. The website can be updated to reflect additional flood events as they occur.
Table 5.1: Examples of flood information for Offaly as recorded on National flood hazard mapping.
Date of flood Description Nov 2009 Location: Portavolla, Banagher, County Offaly. Data gathered by Ferbane Area Engineer, Offaly County Council. (Report Includes: Source, Cause) Heavy rainfall commenced on Wed 18th November, which resulted in flooding events beginning to occur towards the end of that week. Large areas of land and roads were inundated. Buildings were flooded or were in danger of being flooded. Source of flooding: River Shannon. Dec 1954 Location: Counties, Clare, Galway, Leitrim, Limerick, Longford, Offaly, Roscommon, Tipperary, Westmeath (4 flood events recorded). Event duration: October 1954 – Feb 1955: 25,000 acres of farmland flood. 2000 holdings affected in Shannon Basin. Many hundreds of people suffered loss and driven from their flood homes. Livestock drowned, extensive agricultural losses. Recorded as not being an isolated event but another event in a long series of floods affecting the Shannon Basin. Winter 1994/1995 Continuous heavy rainfall during December 1994 and January/February 1995 resulted in severe and prolonged flooding along the Shannon. On the Lower Shannon Catchment downstream of Athlone this flood event was in many aspects the worst on record and can therefore be considered as at least a one in fifty year event. Source: ESB August 2008 After very heavy and prolonged rainfall in Offaly, flooding occurred in several parts of the county. Flood event in Tullamore peaked on the 18th of August 2008 and resulted in the inundation of land both upstream and downstream of Tullamore town centre as well as an area to the north east. Source of flooding: Excessive rainfall and Tullamore River: Source of Information OPW. August 2008 Flood event: Boyne Catchment affecting Edenderry Town. August 2008 Flood Event: River Figile affecting Bracknagh and Clonbullogue Recurring Flood event: Shannon harbor, recurring from River Shannon Recurring Flood event: Bog Lane, Kenny Lane Portarlington recurring from River Barrow
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Recurring Flood event: Fivealley – Report from Area Engineer OCC: Low lying land floods after heavy rain every year. The water flows from surrounding land. Road is liable to flood. It is difficult to alleviate the flooding.
5.3 Sources of Flooding in Offaly.
The review of the historical flooding data shows rivers to be the most common and most damaging source of flooding in County Offaly. In addition, flooding occurs from a number of other sources and these are described below.
5.3.1. Fluvial Flooding
Flooding of watercourses or rivers is associated with the exceedance of the channel capacity, the channel is blocked or restricted and excess water flows on adjacent low lying areas (floodplain). This is known or referred to as fluvial flooding. This can occur in a short range of time or over a prolonged period.
In large, relatively flat catchments, flood levels will rise slowly and natural floodplains may remain flooded for several days, acting as the natural regulator of the flow. In small, steep catchments, local intense rainfall can result in the rapid onset of deep and fast-flowing flooding with little warning. Such “flash” flooding, which may only last a few hours, can cause considerable damage and possible threat to life.
The main locations in County Offaly shown to be at risk from flooding are lands and settlement areas located along the rivers. Fluvial flooding accounts for approximately 80% of events in County Offaly. The major sources of this include the River Shannon to the West of the County, River Barrow at Portarlington, Tullamore River and Figile River in East. Smaller tributaries and drains pose flood risk also.
Fluvial Risk has been primarily identified by the OPW and illustrated succinctly in the form of Flood Zones A, B and C across the County. The Flood Zones have been defined in the Planning System and Flood Risk Management Guidelines and show the areas potentially at risk of flooding from rivers, ignoring the presence of defenses. On identifying fluvial flood extents through Zones A and B in particular, the application of landuse zoning objectives, designations or the location of particular development in settlement plans can be informed greatly. Flood Zones A and B will inform the location and extent of landuse zoning in the development plan. Outside of settlement plan areas, where there is also potential for development i.e. greater rural areas, the identification of Flood Zones A and B can also best inform the most appropriate location for types of development.
5.3.2 Pluvial Flooding Pluvial flooding is defined as being flooding from rainfall that exceeds the infiltration capacity of the ground to absorb it before runoff enters any watercourse or sewer. It is usually associated with high intensity rain events but can also occur with lower intensity rainfall where ground is already saturated, developed or otherwise has low permeability resulting water lying on land/sites. Drainage systems and surface watercourses may become completely overwhelmed. Recent examples of pluvial flooding
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include summer 2008 where floods were experienced all across County Offaly. Pluvial Flooding was highlighted as the greatest contributory factor.
Identifying areas potentially at risk from pluvial flooding is a requirement of the Floods Directive, particularly in relation to the Preliminary Flood Risk Assessments which, as a first stage involves, high level screening of a catchment to determine all sources of potential flood risk.
For the purposes of the SFRA, the identification of areas of pluvial hazard can initially be based on historical data and events. However the following aspects are important in considering when developing land in particular for particular use:
• Presence in the area or site of a flowpath for surface water that may drain an upstream catchment area. • Land-use and sensitivity of the area to flooding: whether there is significant infrastructure, or other buildings that would be particularly vulnerable to pluvial flooding in the vicinity. • Drainage outlet: How the area/site would drain in the event of a significant rainfall event. Is there potential for blockage of this outlet that could exacerbate the pluvial flooding.
These elements can be assessed during a site specific FRA and from a subsequent more detailed review of mapping and other available information at the time.
5.3.3 Groundwater Flooding Groundwater flooding is caused when the level of water stored in the ground rises as a result of prolonged rainfall and meets the ground surface flowing out over it when the capacity of the natural underground reservoir is exceeded. Groundwater flooding tends to be very local and erratic. However such flooding may often result in significant damage to property rather than a potential risk to life.
Groundwater is typically seasonal and its severity can vary from year to year. Extreme groundwater flooding is considered rare. Certain aquifer types are inherently more vulnerable to groundwater flooding than others and as a consequence groundwater cannot be easily managed nor can definitive solutions be designed or engineered.
The Floods Directive requires member states to produce preliminary national flood hazard maps (showing the extent and level of flooding for events of specified probability) and flood risk maps (showing the potential adverse social and economic consequences of flooding) for a range of flood risk types, including groundwater. To date such maps have not been released for examination.
It should be acknowledged that in historical records it may have been difficult to distinguish groundwater and surface water or pluvial flood events.
In the absence of primary groundwater mapping, groundwater vulnerability maps can be a useful proxy particularly in the interest of taking a precautionary approach to flood risk. However it should be noted and acknowledged that the primary function of Groundwater Vulnerability maps is to assess the vulnerability of an aquifer to pollution from ground sources, not for flooding vulnerability. It combines aquifer characteristics and soil leaching potential to provide groundwater vulnerability classes. These
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should be used with caution if being used to predict groundwater emergence because, even though it is a good indicator of permeability of the aquifer, not all areas on a high permeability aquifer would be prone to flooding.
The vulnerability index derived by the GSI is based on a number of parameters: • Subsoils that lie over groundwater • Type of recharge – whether point or diffuse and • Thickness of the unsaturated zone through which contamination moves.
The premise for using the vulnerability maps in the context of groundwater flooding is that the more vulnerable the groundwater is to contamination, the more chance there is of groundwater rising to the surface and causing flooding. As stated previously, this approach is especially precautionary. The GSI mapping indicates that the Extreme and High category of the groundwater vulnerability in County Offaly is sporadically located throughout the County. Extreme groundwater vulnerability is best often shown to be located in close proximity to where there is rock at/near the surface of Karst (limestone). Areas of High Groundwater Vulnerability are also sporadically dispersed throughout the County.
Map 5.1 Groundwater Vulnerability in County Offaly.
County Offaly is predominantly of moderate to high vulnerability with areas of extreme vulnerability limited to Slieve Bloom Mountain areas, Croghan Hill and Walsh Island.
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5.3.4 Flooding from Drainage Systems
Sewer flooding occurs when urban drainage networks become overwhelmed and maximum capacity is reached. This can occur if there is a blockage in the network causing water to back up behind it or if the sheer volume of water draining into the system is too great to be handled. Higher flows are likely to occur during periods of prolonged rainfall, common to the autumn and winter months. This is also when the capacity of the sewer systems is most likely to be reached. During periods of low flow, for example summer months, sewers may become susceptible to blockage as the low flows are unable to transport solids. This leads to deposition and gradual build up of solid debris thus leading to a cyclical problem where flood risk is concerned. In the historical flood data available from the OPW and in particular flood reports by Area Engineers, there were a number of reports relating to flooding caused by blocked drains or water exceeding the drainage capacity. Some of these are listed as recurring events. Generally however, recommendations from Area Engineers once followed through can see an improvement or resolution of flood events. Given the nature of the drainage networks, the nature of flood risk coupled with the historical data reported on flood events associated with flooding from drainage systems it should be noted that it is not effective in predicting future flooding.
5.3.5 Flooding from Canals It is important that canals are included in an SFRA as canals can form a vital land drainage function. Any FRA should also take account of canals. Occasionally, canals can overtop due to high inflows from natural catchments and if overtopping occurs from adjacent water courses. This additional water can be routed/conveyed by the canal which may cause issues elsewhere along the line of the watercourse. It should be noted that there is a residual risk of breach from all raised canals and development should be avoided adjacent to these locations.
There is one canal located within County Offaly. The Grand Canal runs from east to west through the County. There is one record of a breach or overtopping of this canal in the Edenderry area in 1989. The area flooded was recorded as being significant.
Generally however, water levels are constantly monitored and controlled to control the risk of flooding from canals to adjacent properties. It is important, however, that any development proposed adjacent to a canal be investigated on an individual basis regarding flooding issues and should be considered as part of any FRA.
5.4 Flooding Impacts Flood impacts may be direct or indirect, immediate or long term and may affect households and communities, individuals as well as the environment, infrastructure and economy of an area. In the following sections, the impacts of flooding to people, property, infrastructure and the environment is discussed, and assessed in the context of County Offaly.
5.4.1 Flooding Impacts on People
The Planning System and Flood Risk Management Guidelines 2009 explain about the impacts on people and communities and explain how flooding can cause physical injury, illness and loss of life. Deep, fast flowing or rapidly rising flood waters can be particularly dangerous. For example, even shallow water
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flowing at 2 metres per second (m/sec) can knock children and many adults off their feet, and vehicles can be moved by flowing water of only 300mm depth. The risks increase if the floodwater is carrying debris. Some of these impacts may be immediate, the most significant being drowning or physical injury due to being swept away by floods. Floodwater contaminated by sewage or other pollutants (e.g. chemicals stored in garages or commercial properties) is particularly likely to cause such illnesses, either directly as a result of contact with the polluted floodwater or indirectly as a result of sediments left behind. Flood water may also hide other hazards for wading pedestrians, such as manhole openings where the covers have been lifted by flood flows. Those most likely to be at risk are those outdoors on foot or in a vehicle, in a tent or caravan, or in a building, such as a single-storey bungalow or below ground in a basement. The impact on people and communities as a result of the stress and trauma of being flooded, or even of being under the threat of flooding, can be immense.
The 2006 Framework for Major Emergency Management enables the principal response agencies such as An Garda Siochána, the Health Service Executive and local authorities to prepare for and make a co- ordinated response to a variety of major emergencies including flooding. A guidance and protocol document has been developed in conjunction with the OPW for responding to flood events3.
For the purposes of assessing the impacts of flooding on people, the SFRA can only consider the tangible assets such as property.
5.4.2 Flooding Impacts on Property
Flooding can cause severe damage to properties and consequently have impacts on health of occupants. Floodwater may damage internal finishes, contents and electrical and other services and possibly cause structural damage. The physical effects can have significant long-term impacts, with re-occupation sometimes not being possible for over a year. The costs of flooding are increasing, partly due to increasing amounts of electrical and other equipment within developments. For these reasons (and many more) the precautionary approach to developing on areas at risk of flooding is advocated.
Outside of this, the vulnerability of the uses buildings have is important in understanding the impacts on people of the flooding of property. For example the difficulty rating in the evacuation of residents from a nursing home as opposed to people from a retail warehouse development contrasts significantly. In addition it is vitally important that Emergency Services buildings should not be affected by flooding directly, as they are required to be operational during flooding occurrences. Cognisance must be taken of the repercussions in the landuses permitted within the zoning objectives proposed in flood plains. The vulnerability of uses is a significant factor and Table 3.1 of The Planning System and Flood Risk Management Guidelines provides guidance on landuses.
5.4.3 Flooding Impacts on Infrastructure
The damage flooding can cause to businesses and infrastructure, such as transport or utilities like electricity and water supply, can have significant detrimental impacts on local and regional economies. Flooding of primary roads or railways can deny access to large areas beyond those directly affected by the flooding for the duration of the flood event, as well as causing damage to the road or railway itself. Flooding of water distribution infrastructure such as pumping stations or of electricity sub-stations can
3 see http://www.mem.ie
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result in loss of water or power supply over large areas. This can magnify the impact of flooding well beyond the immediate community. The long-term closure of businesses, for example, can lead to job losses and other economic impacts.
In County Offaly there is a total of 1966 km of public roads (excluding Motorway roads and National Primary Roads). Of this total, 130km is located within Flood Zones A and B accounting for 6.6% of all public roads i.e. 110 km in Flood Zone A (5.0%) and 20km in Flood Zone B (1.6%). There is a total of 14.66km of motorway road in County Offaly. Of this, 0.71km (4.8%) is located in Flood Zone A. There is a total of 118.6km of National Primary Roads in County Offaly. 5.7km (4.8%) of the National Primary Roads are located within Zone A with 0.44km (0.37%) located within Flood Zone B. In relation to schools there is 1 post primary school (out of 14 post primary schools in Offaly) located within Flood Zone A. 5 national schools out of the 66 national schools in the County are located within Flood Zones A and B.
Table 5.2: Infrastructure Types Located in Flood Zones A and B in County Offaly. Infrastructure Flood Zone A and B Flood Zone A Flood Zone B No. and % of total % % Hospitals 1 no: Tullamore Regional n/a Hospital (Zone A) Schools 6 No. (7.5% of all schools) 5% 2.5% Railway Stations 0 0 0 Roads (all classes) 1966km 6.1% all public roads in Zones A 5.0% 1.1% and B Roads (M) 14.66km 4.48% Motorway roads within 4.48% 0 zones A and B Roads (N) 118.6km 6.15% National Secondary 4.48% 1.67% routes
5.4.4 Flooding Impacts on the Environment
Significant detrimental environmental effects of flooding can include soil erosion, bank erosion, land sliding and damage to vegetation as well as the impacts on water quality, habitats and flora and fauna caused by bacteria and other pollutants carried by flood water. Flooding can however play a beneficial role in natural habitats. Many wetland habitats are dependant on annual flooding for their sustainability and can contribute to the storage of flood waters to reduce flood risk elsewhere.
In County Offaly there is significant land coverage under the environmental designations i.e.:
9,569 ha. of land designated as Special Protection Areas (SPA). 6,421 ha. of land designated as Special Areas of Conservation (SAC). 1,412 ha. of land designated as Natural Heritage Areas (NHA).
Of these figures: • 2065 ha SPA designation is located within Flood Zones A and B accounting for 21.6 % of total land area covered by the environmental designation.
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• 1769 ha SAC designation is located within Flood Zones A and B accounting for 27.6 % of total land area covered by the environmental designation and • 398 ha NHA designation is located within Flood Zones A and B accounting for 28.2 % of total land area covered by the environmental designation.
Development in the designated sites is constrained by the SAC, NHA and SPA objectives, but in any event would also be required to pass the Justification Test if proposed in the vicinity of the watercourses.
5.5 Climate Change The Planning System and Flood Risk Management Guidelines recommend that a precautionary approach to climate change is adopted due to the level of uncertainty involved in the potential effects. Examples of the precautionary approach include:
• Recognising that significant changes in the flood extent may result from an increase in rainfall or tide events and accordingly adopting a cautious approach to zoning land in these potential transitional areas;
• ensuring that the levels of structures designed to protect against flooding, such as flood defences, land-raising or raised floor levels are sufficient to cope with the effects of climate change over the lifetime of the development they are designed to protect; and
• ensuring that structures to protect against flooding and the development protected are capable of adaptation to the effects of climate change when there is more certainty about the effects and still time for such adaptation to be effective.
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6. Flood Risk Review – Settlements in Offaly
6.1 Land Use Zoning Objectives
The purpose of land use zoning generally is to direct types of uses or development considered appropriate to particular locations. Generally, zoning is designed to reduce conflicting uses within areas, protect existing and planned resources and to ensure that a holistic approach is taken to develop an area.
The Planning System and Flood Risk Management Guidelines direct Planning Authorities to, in the first instance, avoid zoning in areas at risk of flooding or choose lower risk flood zones for new development. Thereafter, Planning Authorities are charged with examining the vulnerability classifications when assessing landuses or developments proposed in areas at risk of flooding. This is over and beyond landuse zoning objectives. It is at this additional level where individual uses may be considered appropriate or not within areas at risk of flooding and lessens the impact of flooding on people, property and infrastructure in the long term. The vulnerability class as well as the landuses and types of development associated with the class are set out in Section 2 and specifically in Table 2.4.
6.2 Flood Risk Identification
Flood risk in each settlement of County Offaly as defined by the settlement hierarchy has been identified and assessed based on the Flood Zones and best available data described in section 4 of this SFRA.
The Planning System and Flood Risk Management Guidelines require the identification of areas at risk of flooding in areas where zoning of land is being considered within the development plan. Tier 6 Sráids and the Open Countryside, of the Settlement Hierarchy comprise areas that are not zoned but have been identified as growth areas in their own right. In the interest of completeness and drawing attention in general to flood risk, this SFRA has examined the flood risk in each of settlement areas identified by the settlement hierachy including the unzoned areas of Sráids and the Open Countryside.
Where settlements have been identified as having a Low Severity or no risk of flooding, no further review of fluvial flooding is required. Where some settlements (all or in part) lie within areas at risk of flooding within either Flood Zone A or Flood Zone B, or demonstrate flood risk from other sources, a precautionary approach to zoning of lands and directing development by using sequential approach, is strongly promoted. In addition to complying with best practice, this takes cognisance of unknown variables such as gaps in data sets and climate change.
The Planning System and Flood Risk Management Guidelines strongly endorse using the precautionary approach for all stages of the planning process such as plan making, development management as well as applicants in preparing their planning applications. The SFRA is consistent with the approach promoted by the guidelines and recommends in the strongest terms that the Planning Authority follows and adopts this approach to flood risk and encourage applicants/developers to do likewise.
Where the precautionary approach is not being taken, giving rise to potential flood risk issues on account of decisions required to be made in relation to land use zoning or the directing of development to certain areas, a Stage 2 SFRA will need to be carried out for areas of particular concern to further appraise flood risk.
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Table 6.1 below identifies flood risk in the Settlement areas in County Offaly as defined in the Settlement Hierarchy. The table should be read in conjunction with the relevant flood maps for each of the settlement areas. These maps contain a visual representation of flood risk indicators relating to the location and extent of Flood Zones A and B, Drainage Districts, Benefiting Lands, Flood Extents and Flood Points. The map illustrates the settlement area as well as surrounding lands that may influence or in some way be a factor in influencing flood risk in certain areas.
It is important to note that the settlement areas have not been defined or delineated in the SFRA. The purpose of the SFRA is to inform the zoning of settlement areas and also the exact location of the development boundaries of the settlement areas. The flood indicators as identified on the maps should not be taken as being entirely reliable but do provide an indication that further assessment of flood risk may be required.
The settlement areas on the flood maps are encircled to highlight and draw attention to their general area. The areas delineated in this manner exceed the development boundaries of all settlement areas delineated for the purposes of the Offaly County Development Plan 2009-2015. For the purposes of this stage 1 SFRA, flood indicators within this defined radius have been identified and used in the assessment of flood risk for each settlement area. In Table 6.1, ‘Settlement Land’ refers to land contained within the identified circle on each settlement map. Further examination and assessment of each settlement will be required to be undertaken when deciding upon and applying zoning objectives. For areas identified as being at risk of flooding, the precautionary approach to zoning is recommended for the settlement plans contained within Volume 2 of the Development Plan.
Table 6.1 should be read in conjunction with the settlement flood maps for each of the settlement areas.
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Table 6.1 Settlement Areas and Flood Risk
Tier 1: Linked Gateway Settlement Land at risk of flooding Comment land4 in from other sources Flood Zone A or B
Tullamore Yes Yes Area assessed previously by FRAM study (2008) and is subject to further flood risk assessment as an AFA. (Map indicating Flood Zone A shown overleaf). Area covered by Tullamore Town and Environs Development Plan 2010-2016. Flood risk is subject to examination and review under the scope of the Tullamore and Environs development plan. Precautionary approach to zoning of land recommended during review period or any variation to the Tullamore and Environs Development Plan.
Sequential approach to be applied to avoid development in areas at risk of flooding through Development Management process. Justification test to be applied in appropriate cases during assessment of planning application and site specific flood risk assessments required to determine appropriateness of development in areas at risk of flooding.
The detailed mapping produced through the Tullamore Flood Study is based on more detailed modelling and analysis (and is similar to those that will be produced for the AFAs through the CFRAM Studies). The FRAM maps should be used in preference to the PFRA maps (OPW).
4 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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Map 6.1 Extract from the Tullamore Town and Environs Development Plan 2010-2016 indicating the 1 in 100 year Flood Event
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Area: Tullamore
Comment: Flood Zones A and B: Yes
Flood events reported: Part of Tullamore urban area is located on the Tullamore River Floodplain (inclusive of Barony River Tributary). Historically subject to inundation subjecting residential, commercial and industrial properties to ongoing flood risk. Flood points widely dispersed throughout urban area.
Flood Study undertaken: FRAM study undertaken on account of urban development pressure on Tullamore River floodplain upstream and downstream of existing urban area.
AFA: Tullamore has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other: The detailed mapping produced through the Tullamore Flood Study is based on more detailed modelling and analysis (and is similar to those that will be produced for the AFAs through the CFRAM Studies). The FRAM maps should be used in preference to the PFRA maps (OPW). Source of data: Estimated Severity: National Flood Hazard Mapping and reports. Extreme.
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Table 6.1 Contd
Tier 2: Key Service Towns Settlement Land at risk of flooding Comment land5 in from other sources Flood Zone A or B Birr subject to further flood risk assessment as Birr Yes Yes an AFA. Area covered by Birr Town and Environs Development Plan 2010-2016. Flood risk is subject to review under the scope of the Birr and Environs Development Plan. Precautionary approach to zoning of land recommended during review period or any variation to the plan.
Sequential approach to be applied to avoid development in areas at risk of flooding through Development Management process. Justification test to be applied in appropriate cases during assessment of planning application and site specific flood risk assessments required to determine appropriateness of development in areas at risk of flooding. Edenderry Yes Yes Edenderry subject to further flood risk assessment as an AFA. Area covered by Local Area Plan and flood risk subject to review under the scope of this plan. Precautionary approach to zoning of land recommended in preparation of new plan or any variation to the plan for the area.
Sequential approach to be applied to avoid development in areas at risk of flooding through Development Management process. Justification test to be applied in appropriate cases during assessment of planning application and site specific flood risk assessments required to determine appropriateness of development in areas at risk of flooding. Portarlington Yes Yes Portarlington assessed previously by flood risk and management strategy (2007). Area covered by Joint Local Area Plan and flood risk is dealt with in plan and SFRA accompanying the LAP.
Sequential approach to be applied to avoid development in areas at risk of flooding through
5 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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Development Management process. Justification test to be applied in appropriate cases during assessment of planning application and site specific flood risk assessments required to determine appropriateness of development in areas at risk of flooding.
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Area: Birr
Comment: Flood Zones A and B: Yes
Flood events reported: Flood points liable to flooding after heavy rain. Camcor River flowing through town deals well with inundation.
Flood Study undertaken: No.
AFA: Birr has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFA’s will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other:
Source of data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High.
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Area: Edenderry
Comment: Flood Zones A and B: Yes
Flood events reported: Flooding of lands and Edenderry Golf Course located on floodplain, recorded from River Boyne located to north and north east of the town. Recurring flood points at Kishawanny Bridge and Blundell Aqueduct – terrain is low lying and flat. Breach of Grand Canal embankment 1989 – significant area flooded. Slow rate of drainage of surface water reported on account of poor draining peat soils. Recurring in times of heavy or prolonged rainfall.
Flood Study undertaken: No.
AFA: Edenderry and its Environs have been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFA’s will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other: Source of data: Estimated Severity: National Flood Hazard Mapping and reports. High.
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Area: Portarlington
Comment:
Flood Zones A and B: Yes
Flood events reported: Flooding caused by exceedance of River Barrow capacity after heavy and prolonged rainfall. Recurring flood events annually reported. Flood events cause damage to residential, commercial and industrial premises.
Flood Study undertaken: Portarlington Flood Risk and Management Strategy completed in 2007.
AFA: No.
Other: Portarlington is located between the two administrative boundaries of Offaly County Council and Laois County Council. Part of Portarlington Urban area is located within Flood plain area of the River Barrow.
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High.
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Table 6.1 Contd
Tier 3: Service Towns Settlement Land at risk of flooding Comment land6 in from other sources Flood Zone A or B Clara Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Ferbane Yes No Precautionary approach to zoning of land in areas at risk of flooding.
6 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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Area: Clara
Comment:
Flood Zones A and B: Yes – River Brosna.
Flood events reported: Subject to historic flooding events and recurring events – inadequate surface water system reported as contributing to flood risk.
Flood Study undertaken: No.
AFA: Clara has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High.
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Area: Ferbane
Comment:
Flood Zones A and B: Yes – River Brosna.
Flood events reported: No flood events reported. No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Table 6.1 Contd
Tier 4: Local Service Settlement Land at risk of flooding Comment Towns land7 in from other sources Flood Zone A or B Banagher Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Daingean Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Kilcormac Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
7 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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Area: Banagher
Comment:
Flood Zones A and B: Yes – River Shannon.
Flood events reported: Part of the urban area of Banagher is located with the floodplain of the River Shannon. Area subject to inundation on recurrent basis. Flooding of residential, commercial and industrial properties reported.
Flood Study undertaken: No.
AFA: No.
Other:
Source of data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High
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Area: Daingean
Comment:
Flood Zones A and B: Yes – Philipstown River.
Flood events reported: Part of the urban area of Daingean is located in the floodplain of the Philipstown River. Flood events recorded on annual basis.
Flood Study undertaken: No.
AFA: Daingean has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High.
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Area: Kilcormac
Comment:
Flood Zones A and B: Yes – Silver River.
Flood events reported: Sliver River flows through north eastern part of the town. Historical flood event recorded.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate
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Table 6.1 Contd
Tier 5: Villages Settlement Land at risk of flooding Comment land8 in from other sources Flood Zone A or B Ballinagar No No Flooding not a risk/consideration.
Ballycumber Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Belmont No No Flooding not a risk/consideration.
Bracknagh No Yes Precautionary approach to zoning of land in areas at risk of flooding.
Cloghan No No Flooding not a risk/consideration.
Clonbullogue Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Cloneygowan No No Flooding not a risk/consideration.
Coolderry No No Flooding not a risk/consideration.
Crinkle Yes No Precautionary approach to zoning of land in areas at risk of flooding. To Note: Crinkle is included and provided for in plan area of the Birr Town and Environs Development Plan.
Geashill No Yes Precautionary approach to zoning of land in areas at risk of flooding.
Killeigh No No Flooding not a risk/consideration.
Kinnitty No Yes Precautionary approach to zoning of land in areas at risk of flooding.
Mucklagh Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Moneygall No Yes Precautionary approach to zoning of land in areas at risk of flooding.
8 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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Tier 5: Villages Settlement Land at risk of flooding Comment land9 in from other sources Flood Zone A or B Mountbolus No No Flooding not a risk/consideration.
Pollagh/Leamanaghan Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Riverstown Yes No Precautionary approach to zoning of land in areas at risk of flooding. To Note: Riverstown is included as a village within the plan boundary of the Birr Town and Environs Development Plan. Shannonbridge Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Shannon Harbour Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Shinrone Yes Yes Precautionary approach to zoning of land in areas at risk of flooding.
Rahan Yes No Precautionary approach to zoning of land in areas at risk of flooding.
Rhode No No Flooding not a risk/consideration.
Walsh Island No No Flooding not a risk/consideration.
9 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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Area: Ballinagar
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping Low
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Area: Ballycumber
Comment:
Flood Zones A and B: Yes – River Brosna.
Flood events reported: Flood events reported - January 1995 – Surface water entering village from west. Flooding of properties recorded. 2005 – Area Engineer reports recurring events whereby Mill Race overflows its banks after very heavy rainfall and water flows down the road.
Flood Study undertaken: No.
AFA: No.
Other: Council have undertaken remedial work.
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate.
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Area: Belmont
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Low
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Area: Bracknagh
Comment: Flood Zones A and B: Yes – Figile River.
Flood events reported: Flood events (recurring) reported encroaching towards the settlement area from River Figile.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate.
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Area: Cloghan
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Clonbullogue
Comment:
Flood Zones A and B: Yes – Philipstown River and Figile River.
Flood events reported: Subject to recurring flood events during winter from River Figile.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High.
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Area: Cloneygowan
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Coolderry
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Crinkle
Comment: Flood Zones A and B: Yes – Brosna River.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: Birr has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs). Crinkle will be assessed as part of this by virtue of its location and proximity to Birr and in particular the Brosna River.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low.
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Area: Geashill
Comment: Flood Zones A and B: No.
Flood events reported: Flood Events recorded from adjoining lands into village core.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate
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Area: Killeigh
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Kinnitty
Comment: Flood Zones A and B: No.
Flood events reported: Flood events recorded on account of discharge from upstream catchments in Slieve Blooms and inability of infrastructure to deal with in times of inundation.
Flood Study undertaken: No.
AFA: No.
Other: Culvert has been replaced – may need to be appraised in times of heavy and prolonged rainfall.
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate
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Area: Moneygall
Comment: Flood Zones A and B: No.
Flood events reported: Affected by flood events as a result of heavy rainfall in village centre from run-off from Army’s Hill.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. High
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Area: Mountbolus
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Mucklagh
Comment:
Flood Zones A and B: Yes – Clodiagh River.
Flood events reported: Flooding experienced on Brocca road in Mucklagh.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate
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Area: Pollagh/Leamanaghan
Comment: Flood Zones A and B: Yes – River Brosna.
Flood events reported: Significant history of flooding from River Brosna - may have improved with works undertaken to River Brosna.
Flood Study undertaken: No.
AFA: Pollagh has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAss will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs). Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate to High
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Area: Rahan
Comment: Flood Zones A and B: Yes – Clodiagh River.
Flood events reported: Recurring flood events in Killina south east of Rahan.
Flood Study undertaken: No.
AFA: Rahan has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other: Rahan is located on Clodiagh River. May be subject to flood risk by virtue of its location downstream of Tullamore Urban Area. Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low to moderate.
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Area: Rhode
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Riverstown
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Low. Report.
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Area: Shannonbridge
Comment: Flood Zones A and B: Yes – River Shannon.
Flood events reported: Significant history and impact of flooding from River Shannon.
Flood Study undertaken: No.
AFA: Shannonbridge – Power station has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs). Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Extreme.
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Area: Shannon Harbour
Comment: Flood Zones A and B: Yes – River Shannon.
Flood events reported: Significant history and impact of flooding from River Shannon.
Flood Study undertaken: No.
AFA: Shannon Harbour has been identified as an ‘Area for Further Assessment’ (AFA) under the National Preliminary Flood Risk Assessment (PFRA) carried out by the OPW. More detailed assessment will be undertaken to more accurately assess the extent and degree of flood risk. Where significant risk is confirmed, possible mitigation measures will be developed to manage and reduce the risk. AFAs will be undertaken through Catchment Flood Risk Assessment and Management Studies (CFRAMs).
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Extreme.
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Area: Shinrone
Comment: Flood Zones A and B: No.
Flood events reported: Recurring flood event after heavy rainfall because of low lying lands.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low.
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Area: Walsh Island
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
Table 6.1 Contd
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To Note: Sráids and Open Countryside are unzoned settlement areas. Sráids are rural settlement areas defined by a development envelope only. The precautionary approach is to be applied to define the development envelope in addition to avoiding development in areas at risk of flooding through the Development Management process. Justification test to be applied in appropriate cases during assessment of planning application and site specific flood risk assessments required to determine appropriateness of development in areas at risk of flooding.
Tier 6 Sráids and Open Settlement Land at risk of flooding Comment Countryside land10 in from other sources Flood Zone A or B Ballinamere No Yes Precautionary approach to be applied in defining development envelope and in avoiding development in areas at risk of flooding. Ballyboy Yes No Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding.
Ballyfore No No Flooding not a risk/consideration.
Blueball No No Flooding not a risk/consideration.
Boher No No Flooding not a risk/consideration.
Boora (Leabeg) No No Flooding not a risk/consideration.
Brosna Yes Yes Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding.
Cadamstown Yes No Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. Clareen Yes No Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. Clonfinlough Yes No Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. Croghan No No Flooding not a risk/consideration.
Doon No No Flooding not a risk/consideration.
Dunkerrin Yes No Precautionary approach to be applied to defining development envelope and in avoiding
10 ‘Settlement land’ refers to the area encircled on the settlement flood maps.
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development in areas at risk of flooding. .
Durrow No No Flooding not a risk/consideration.
Fivealley No Yes Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. Garryhinch Yes Yes Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. High Street No No Flooding not a risk/consideration.
Horseleap Yes No Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. Killina Yes Yes Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding.
Killurin No No Flooding not a risk/consideration.
Killyon Yes No Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding. Lusmagh No No Flooding not a risk/consideration.
Rath No No Flooding not a risk/consideration.
Roscomroe No No Flooding not a risk/consideration.
Tober No Yes Precautionary approach to be applied to defining development envelope and in avoiding development in areas at risk of flooding.
Open Countryside Yes Yes Sequential approach to be applied to avoid development in areas at risk of flooding.
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Area: Ballinamere
Comment:
Flood Zones A and B: No.
Flood events reported: One flood event recorded from surface water on road.
Flood Study undertaken: No.
AFA: No.
Local Authority undertook remedial works. Flood risk reduced. Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Ballyboy
Comment: Flood Zones A and B: Yes – Silver River.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Ballyfore
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Blueball
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Boher
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Boora (Leabeg)
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Brosna
Comment:
Flood Zones A and B: No.
Flood events reported: Recurring flood event from River Brosna due in large part to inundation.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate
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Area: Cadamstown
Comment:
Flood Zones A and B: Yes - Silver River.
Flood events reported: High water levels recorded in Sliver River in August 2008 giving rise to flood point, north of the settlement area.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Clareen.
Comment:
Flood Zones A and B: Yes – Fuarawn River.
Flood events reported: Flood point to south of settlement area. Area subject to flooding from surface runoff after prolonged heavy rain.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Clonfinlough.
Comment: Flood Zones A and B: Yes – Fin Lough.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Croghan.
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Doon.
Comment: Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Dunkerrin
Comment:
Flood Zones A and B: Yes.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Durrow.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Fivealley.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Low lying land to south east of development envelope experiences floods after heavy rain every year from surface run off from adjoining lands. Road is liable to flood and is reported to be difficult to alleviate.
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Garryhinch.
Comment:
Flood Zones A and B: Yes – River Barrow.
Flood events reported: Flood point to south of development envelope on lands located within the flood plain of River Barrow. Recurring flood event where road is subject to flooding.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: High Street.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Horseleap.
Comment:
Flood Zones A and B: Yes – Gageborough River.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Killina.
Comment:
Flood Zones A and B: No.
Flood events reported: 2 Flood events recorded: August 2008 Flood event: Flooding experienced in Killina after heavy and prolonged rainfall and recurring flood event: Low lying land flood after heavy rain every year. Road is liable to flood.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Moderate
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Area: Killurin.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other:
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Killyon.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Lusmagh
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Rath.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Roscomroe.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Area: Tober.
Comment:
Flood Zones A and B: No.
Flood events reported: No flood history and no fluvial flood risk identified.
Flood Study undertaken: No.
AFA: No.
Other: Recurring flood event recorded: Low lying land floods annually. Road liable to flooding at school entrance.
Source of Data: Estimated Severity: National Flood Hazard Mapping: Local Area Report. Low
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Open Countryside
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6.3 Summary of Settlements identified as being at risk of flooding:
The identification of flood risk is the first step in managing flood risk within the planning process. Information relating to flood identification from this section should be used to inform the zoning of lands and the delineation of the development boundaries or envelopes in Volume 2 of the Development Plan. Table 6.2 below identifies the list of settlements which require closer examination in the context of flood risk and for the purposes of zoning and delineating settlement boundaries or envelopes. Section 8 of this stage 1 SFRA includes a concluding statement which explains how each of the affected settlement areas as identified in Table 6.2 have addressed the issue of flood risk by way of appropriate low vulnerability zonings and/or the delineation of development boundaries or envelopes in applying the precautionary approach to avoiding development in areas at risk of flooding.
Table 6.2: Summary of Settlements identified as being at risk of flooding:
Number Settlement Area Name Additional Comments 1 Linked Gateway Tullamore AFA under PFRA 2 Key Service Town Birr AFA under PFRA 3 Key Service Town Edenderry AFA under PFRA 4 Key Service Town Portarlington 5 Service Towns Clara AFA under PFRA 6 Service Towns Ferbane 7 Local Service Town Banagher 8 Local Service Town Daingean AFA under PFRA 9 Local Service Town Kilcormac 10 Village Ballycumber 11 Village Bracknagh 12 Village Clonbullogue 13 Village Crinkle AFA under PFRA as part of Birr. 14 Village Geashill 15 Village Kinnitty 16 Village Mucklagh 17 Village Moneygall 18 Village Pollagh/Leamanaghan AFA under PFRA 19 Village Riverstown 20 Village Shannonbridge AFA under PFRA 21 Village Shannonharbour AFA under PFRA 22 Village Shinrone 23 Village Rahan AFA under PFRA 24 Sráid Ballinamere 25 Sráid Brosna 26 Sráid Cadamstown 27 Sráid Clareen 28 Sráid Clonfinlough 29 Sráid Dunkerrin 30 Sráid Fivealley 31 Sráid Garryhinch
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32 Sráid Horseleap 33 Sráid Killina 34 Sráid Killyon 35 Sráid Tober 36 Open Countryside Sites to be assessed individually
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7. Policy Approach to Flood Risk in Offaly.
This section of the SFRA examines the Policy Approach to flood risk in Offaly and sets out the overarching planning principles which set the context for the policy considerations for planning authorities, decision makers and planning on flood risk management through the various planning processes.
7.1 Introduction This section provides recommendations for what should be the policy approach for flood risk management in addition to guidance as to how best to deal with flood risk management. Flood risk policy is considered essential to ensure that the recommended development control conditions can be imposed consistently at both the plan making decision stage and the planning application stage. The suggested policies put forward in this section take a strong lead from the provisions of The Planning System and Flood Risk Management Guidelines 2009. Given the evolving nature of flood information as further analysis is undertaken, the policy recommendations provided in this section are not exhaustive and it is therefore recommended that the users of this SFRA consult with officials of the planning department of Offaly County Council to be fully informed on the most up to date position in relation to flood risk management.
This section deals with the following: • Planning principles, • Planning policy for plan making, • Development Management and Flooding and • Planning Guidance.
7.2 Planning Principles The policy approach to flood risk in County Offaly as well as guidance in this area is based entirely on best planning principles in the area of flood risk. These planning principles help frame appropriate and necessary policies and guidance for the decision maker, development management and developers or land owners.
• Identify Flood Risk at an early stage in the planning process. • AVOID or minimise development in areas at risk of flooding. • Permit development in areas at risk of flooding ONLY where there is no alternative or reasonable site available in areas at lower risk. • Select an appropriate landuse where development is NECESSARY in areas at risk of flooding. • A precautionary approach to be taken to reflect uncertainties in flood datasets, to provide for climate change and performance of flood defenses. Development should be designed with consideration of possible future changes in flood risk including the effect of climate change. • Land required for current and future flood management e.g. Conveyance and storage of flood water and flood protection schemes should be identified and safeguarded from development. • Flood risk to, and arising from new development should be managed through location, layout and design incorporating Sustainable Drainage Systems and compensation for any loss of floodplain should be compensated for elsewhere.
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• Strategic Environmental Assessment (SEA) of development plans and local area plans should include flood risk as one of the key environmental criteria against which such plans are assessed where flood risk has been identified. (The SEA process provides an opportunity to assess and consider flood risk with respect to other planning and environmental considerations and should be used to show how the sequential approach to managing flood risks has been executed).
7.2.1 The Sequential Approach
The Sequential Approach is a simple decision-making tool designed to ensure that areas at little or no risk of flooding are developed in preference to areas at higher risk. The Planning System and Flood Risk Management Guidelines for Planning Authorities 2009 set out the requirement to apply the Sequential Approach. The aim of the Sequential Approach should be to keep all new development out of medium and high risk areas (Flood Zones A and B) and locations affected by other sources of flooding. Opportunities to locate new developments in reasonably available areas of little or no flood risk should be explored, prior to any decision to locate them in areas of higher risk.
The Sequential approach is a key component of the hierarchical approach to avoiding and managing flood risk and as shown in previous sections can be used by many players in the process. This demonstrates a methodical and consistent approach is applied at all times.
Sequential Approach steps:
• The sequential approach requires the identification and understanding of flood risk across all potential development areas using whatever sources of data are available. Flood Zones A, B and C need to be identified.
• On identification of Flood Zones A, B and, C this step requires the avoidance of zoning proposals or developing in Flood Zones A and B.
• Substitute landuses/development proposed in Flood Zones A and B for less vulnerable uses / development or water compatible development.
• If the uses/development are unable to be substituted for less vulnerable uses/development or water compatible development, then the Justification Test must be applied and passed. The Justification Test should only be carried out when it is not possible, or consistent with wider sustainability objectives, for the development to be located in areas of lower probability of flooding.
• Justification test fails – seek an alternative site or return to less vulnerable uses/water compatible uses.
• Justification test passes – prepare water management proposals to mitigate against the unacceptable affects of flood risk.
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7.2.1.1 Application of the Sequential Approach to Other Sources of Flooding
Development proposals in any location inclusive of Flood Zones A and B must take into account the likelihood of flooding from sources other than rivers. The principle of locating development in lower risk areas should therefore be applied to other sources of flooding. The information collated within the SFRA has identified areas in which risk from other sources of flooding is likely to be an important consideration. The Planning Authority should therefore use the Sequential Approach to steer new development away from areas at risk from other sources of flooding, as well as fluvial.
7.2.1.2 Application of the sequential approach in areas not zoned for development In the case of unzoned land such as those within the Sráid development envelopes and the Open Countryside the Development Management process will seek to assess flood risk potential from first principles. The SFRA will have identified flood risk in these unzoned areas but the sequential approach will come into play in earnest for applications on such lands. As with any planning application in areas at risk of flooding the developer, the applicant or landowner should discuss their proposal at an early stage with the Planning Authority to obtain guidance on how best to deal with flood risk issues.
7.2.2 Justification Test The sequential approach will seek to avoid or substitute land uses in most cases. However, it is acknowledged that there may be situations where a Planning Authority may need to consider the future development of areas at high or moderate risk of flooding, for uses or development vulnerable to flooding that would generally be inappropriate. In such cases, the Planning Authority must be satisfied that the landuse or development can clearly demonstrate on a solid evidence base that the zoning or designation for development or the development itself will satisfy the Justification Test.
In the planning process there are two Justification Tests at different stages:
• Plan Making Justification Test (for development plans). • Justification Test for development management.
7.2.2.1 Plan Making Justification Test (for development plans).
Where, as part of the preparation and adoption or variation and amendment of a development/local area plan, a Planning Authority is considering the future development of areas in an urban settlement that are at moderate or high risk of flooding, for uses or development vulnerable to flooding that would generally be inappropriate as set out by applying the sequential approach, all of the following criteria must be satisfied:
1. The urban settlement is targeted for growth under the National Spatial Strategy, Regional Planning Guidelines, and statutory plans as defined above or under the Planning Guidelines, Planning Directives or in accordance with the provisions of the Planning and Development Act, 2000, as amended.
2. The zoning or designation of the lands for the particular use or development type is required to achieve the proper planning and sustainable development of the urban
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settlement and, in particular: (i) Is essential to facilitate regeneration and/or expansion of the centre of the urban settlement; (ii) comprises significant previously developed and/or under-utilised lands; (iii) Is within or adjoining the core of an established or designated urban settlement; (iv) will be essential in achieving compact and sustainable urban growth, and (v) there are no suitable alternative lands for the particular use or development type, in areas at lower risk of flooding within or adjoining the core of the urban settlement.
3. A flood risk assessment to an appropriate level of detail has been carried out as part of the Strategic Environmental Assessment as part of the development plan preparation process, which demonstrates that flood risk to the development can be adequately managed and the use or development of the lands will not cause unacceptable adverse impacts elsewhere.
N.B. The acceptability or otherwise of levels of any residual risk should be made with consideration for the proposed development and the local context and should be described in the relevant flood risk assessment.
7.2.2.2 Justification Test for Development Management. The justification required in this instance is to be undertaken and submitted by the applicant.
When considering proposals for development, which may be vulnerable to flooding, and that would generally be inappropriate, all of the following criteria must be satisfied:
1. The subject lands have been zoned or otherwise designated for the particular use or form of development in an operative development plan, which has been adopted or varied taking account of The Planning System and Flood Risk Managment Guidelines, 2009.
2. The proposal has been subject to an appropriate flood risk assessment that demonstrates:
(i) The development proposed will not increase flood risk elsewhere and, if practicable, will reduce overall flood risk; (ii) The development proposal includes measures to minimise flood risk to people, property, the economy and the environment as far as reasonably possible; (iii) The development proposed includes measures to ensure that residual risks to the area and/or development can be managed to an acceptable level as regards the adequacy of existing flood protection measures or the design, implementation and funding of any future flood risk management measures and provisions for emergency services access, and (iv) The development proposed addresses the above in a manner that is also compatible with the achievement of wider planning objectives in relation to development of good urban design and vibrant and active streetscapes.
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The acceptability or otherwise of levels of residual risk should be made with consideration of the type and foreseen use of the development and the local development context.
In relation to development on zoned lands where the sequential approach has not been applied in the operative development plan, the applicant is required in consultation with the Planning Authority, to prepare an appropriate SFRA and to meet the criteria of the Justification Test as it applies to plan making. The Planning Authority will thereafter assess the proposal against the Justification Test as it applies to the development management process. Where the information is not sufficient to fully assess the issues involved, the development should not be approved on the basis of flood risk and/or on the grounds of prematurity until appropriate information is available to adequately assess flood risk.
7.3 Planning Policy for Plan Making The responsibility to formulate flood risk policies and seek their implementation lies with the Planning Authority. The SFRA recommends that flood risk policies are taken into account during the plan making process for development or local area plans and, where appropriate, used to strengthen or enhance the planning application assessment process (development management) for specific developments or sites.
The flood risk policies outlined below set out a defined framework for decision makers, planning authorities and developers/landowners alike and demonstrate the consistent and methodical approach to dealing with flood risk at various stages of the planning process.
7.3.1 Policy Considerations for planning authorities and decision makers at plan making stage
Policy considerations applicable to the plan making stage or process are directed by The Planning System and Flood Risk Management Guidelines for Planning Authorities 2009.
The aims of the aforementioned guidelines are to ensure that flood risk is taken into account at all stages in the planning process to avoid inappropriate development in areas at risk of flooding, and to direct development away from areas at highest risk (by applying the sequential approach). After the application of the sequential approach, if development is still needed in areas at risk of flooding to meet wider sustainability objectives, the “Justification Test” is applied to take account of considerations such as social and economic regeneration. In these cases the justification test aims to make development safe without increasing flood risk elsewhere and where possible, reducing flood risk overall. The sequential approach and (if appropriate) the justification test are required to be applied to all plans which allocate land for future development in areas at risk of flooding.
The SFRA advocates the implementation of such polices in helping decision makers and Planning Authorities at a strategic level to direct appropriate development to appropriate locations. The implementation of these policies will be central facet of the core strategy of any development plan or local area plan and in particular, will be fundamental in directing strategy for development in settlement areas.
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Recommended Policies for dealing with flood risk in Plan Making Process
1. To identify areas at risk of flooding by way of a range of data sources and in particular areas
where significant conflict between flood risk and development may exist.
2. To adopt a comprehensive risk based planning approach and to avoid locating development lands in areas at risk of flooding. Where this is not possible, minimise flood risk by selecting alternative less vulnerable landuses.
3. Where the location development land in areas at risk of flooding is unavoidable, to apply the sequential approach and plan making justification test and consider location or re-location according to the outcomes of the aforementioned processes.
4. To develop appropriate flood risk mitigation and management measures for developments located in flood risk areas.
5. To identify areas where further detailed Flood Risk Assessments are required and give guidance as to who is responsible for undertaking such FRA and in what area(s).
In terms of the alignment of the SFRA with the Strategic Environmental Assessment (SEA) it is recommended that the SFRA will be used within the SEA process to assess the suitability of, and options for, land use scenarios. Such scenarios are required to be examined by the SEA and flood risk issues are fundamental considerations in informing any proposed growth scenarios.
7.3.2 Policy Considerations for inclusion in development plans/local area plans.
Incorporating flood risk policies into development plans or local area plans serves to enhance certainty and clarity at this stage of the planning process. Flood risk policies to be incorporated into development plans are also directed by The Planning System and Flood Risk Management Guidelines for Planning Authorities 2009. In addition to demonstrating consistency with the policies recommended for implementation in the plan making process, it also demonstrates alignment with other spatial plans and processes on the issue of flood risk. The Planning System and Flood Risk Management Guidelines also suggest other flood risk management policies for inclusion in development plans in an effort to be pro- active in addressing flooding.
At the stage where a Planning Authority is seeking to deal with flood risk issues for inclusion into development plans it should be recognised that most flood risk issues should already have been raised and possibly addressed at a more strategic level in the plan making stage. Therefore, as consideration has already been undertaken of flood risk in respect of zoned areas and the precautionary approach as promoted has been applied, flood risk issues may be lessened and there may be less need for a prescriptive approach.
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Notwithstanding this, and edging on the precautionary side, the SFRA recommends that development plans set out a clear and sound overall strategy for dealing with flood risk issues and to thread the appropriate elements of this flood risk strategy through various aspects of those plans including Core Strategy, Environment, Infrastructure, Settlement Landuse Plans and perhaps site specific policies etc. Consistency in approach is fundamental to the successful implementation of the flood risk strategy. Therefore the SFRA recommends that the overall flood risk strategy for development plans should set out a clear premise supported by robust policies which would again see a methodical approach being undertaken.
Recommended overall strategy for flood risk:
The Planning Authority must strike a reasonable balance between avoiding flood risk and facilitating necessary development, enabling future development to avoid areas of highest risk and ensuring that appropriate measures are taken to reduce flood risk to an acceptable level for
those developments that have to take place, for reasons of proper planning and sustainable
development, in areas at risk of flooding.
Emphasis added as a level of substantiation is required as promoted by supporting policies.
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Supporting Policies or Objectives (as Planning Authority considers appropriate) for flood risk for inclusion in Development Plans/Local Area Plans:
• Inappropriate types of development that would create unacceptable risk from flooding should not be planned for or permitted.
• Requirement for the use of the Sequential Test to avoid areas at risk of flooding and to direct and locate new development in areas at least risk of flooding i.e. Flood Zone C, avoiding Flood Zones A and B.
• Where developing areas or individual sites at risk of flooding, requirement to use the Sequential Test and Approach within development sites to inform site layout by locating LAP policiesthe can most reinforce vulnerable develop elements plan policies of a –development room to be more in the specific. lowest risk areas. For example, areas located in Flood Zone A and B for less vulnerable uses such as for recreation, amenity and environmental purposes thus providing for an effective means of flood risk management as well as providing connected green spaces with consequent social and environmental benefits.
• Policies to align flood risk management with recreation, amenity and environmental functions.
• Requirement for development proposals to be accompanied by a detailed explanation of how the Development Management Justification Test has been met where proposals for
development may be vulnerable to flooding (Box. 5.1: The Planning System and Flood Risk
Management Guidelines, 2009).
• Development Management standards to provide more detailed assessment frameworks
for planning applications where flooding is an issue, including the need for assessment of types of flooding (other than river flooding) and the impacts of run-off from development.
• Preservation of riparian strips along rivers free from development and of adequate width to permit access to rivers for maintenance.
• Policies for design and development standards that seek to manage the risks associated with flooding to acceptable levels through flood resistant and flood resilient construction where avoidance is not possible.
• Policies for the promotion and incorporation of Sustainable Drainage Systems (SuDS) to ensure that a positive gain in floodplain storage capacity is provided on-site and ensure that there is no negative impact on flood conveyance routes.
• Identification and indication of flood risk management infrastructure and works to be carried out by the OPW, the Local Authority or the developer to facilitate development or to protect existing development, including any further studies or plans to be prepared relating to flood risk management.
• Any other policies/objectives considered appropriate or necessary by the Planning Authority to address the issue of flood risk.
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7.4 Development Management and Flooding
7.4.1 Role of Good Development Management Development Management for flooding should be based on sound strategy and policies and objectives in the development plan. Notwithstanding the availability of flood zone maps and a SFRA, the applicant is primarily responsible in the first instance for assessing whether there is a flood risk issue and how it will be addressed in the development they propose.
The applicant is responsible at pre-application stage to gather relevant information sufficient to identify and assess all sources of flood risk and the impact of drainage from the proposal.
The Planning Authority should ensure that applicants are made aware of any flood risk issues and of the need for them to submit and appropriate flood risk assessment (refer to section 7.4.1).
The assessment of the planning application on flood risk should be based principally on the policies and objectives of the development plan. The Planning Authority should adopt a risk based sequential and balanced approach that gives priority to development in areas of lowest risk, while at the same time allowing consideration of appropriate and necessary development through the use of the sequential approach (please refer to section 7.2.1) based on flood zones and the application of the Justification Test (please refer to section 7.2.2).
Flood risk may constitute a significant environmental effect of a development proposal and in certain circumstance may trigger a sub-threshold Environmental Impact Statement (EIS).
The Planning Authority in assessing all relevant and appropriate information relating to flood risk may ultimately decide to grant permission or refuse permission:
• Grant permission with conditions will be the outcome of the development proposal passing the sequential approach/justification test. Residual risks are considered acceptable following flood mitigation measures and flood mitigation can be dealt with by reasonable conditions (e.g. Appropriate use of SuDs). • Refuse permission will be the outcome of a development proposal not addressing flood issues. Residual risks are considered unacceptable, the application is inconsistent with development plan policies and objectives in relation to flood risk management or the proposal is premature prior to taking a review of the flood risk in the development plan.
7.4.2 Site Specific Flood Risk Assessments Site-specific flood risk assessments (FRAs) will be required for most proposed developments in areas at risk of flooding and the level of detail will depend on the level of flood risk at the site. A FRA should assess flooding from other sources at the site-specific level and offer mitigating options for the management of the risk, without increasing flood risk elsewhere. The onus is on the developer to provide this information in support of a planning application. Prior to undertaking a FRA, developers should ensure that the Sequential Test has been passed at the site to ensure that a site-specific FRA is required and that unnecessary time and expenditure is avoided.
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Key outputs from Site Specific FRA are detailed in Appendix A of The Planning System and Flood Risk Management Guidelines and should be included by developers in the FRA accompanying any application for development within areas at risk of flooding.
7.4.2 Sustainable Urban Drainage Systems (SuDS)11 Development of previously ‘green’ or permeable land within an urban area increases the impermeable area. Rain falling on impervious surfaces is usually directed into a receiving watercourse through surface water drainage systems. Although such drainage systems are effective at transferring surface water quickly, they provide only limited attenuation causing the volume in the receiving watercourse to increase more rapidly and increasing flood risk. SuDS can play a role in reducing and managing run-off to surface water drainage systems as well as improving water quality and contributing to local amenity. SuDS comprise a range of techniques, designed to mimic natural drainage conditions including swales, basins, ponds and infiltration systems.
Although not all will be appropriate for individual development sites, a suitable drainage approach should be possible on almost every site. To obtain the most benefit, SuDS must be considered as early as possible in the planning process. All new development sites will require the following:
• The drainage system to be designed to accommodate all storm events up to and including the 1% AEP (1 in 100 year) event, with an appropriate allowance for climate change • A hierarchical approach should be applied to the SUDS used, in order of priority: . Preventative measures ensuring there are no unnecessary impermeable areas on-site . Source control measures such as rainwater harvesting and infiltration systems, provided the site conditions are appropriate . Site control measures, where prevention and source control measures alone cannot deal with all on-site drainage. Above ground site control attenuation systems, such as balancing ponds and swales, should be considered in preference to below ground attenuation, due to the water quality, biodiversity and amenity benefits they offer.
• A hierarchical approach should be applied to the disposal of surface water from the site referencing in order of priority: . Rainwater harvesting systems . An adequate soakaway or other adequate infiltration system . A watercourse . A surface water sewer
• Where prevention, source control/infiltration cannot deal with all on-site site drainage, for both Greenfield and Brownfield sites, the development runoff volumes and peak flow rates leaving the site should be attenuated to the Greenfield discharge conditions. (It is noted that on brownfield sites it is not always practicable to attenuate flows to Greenfield rates).
• Exceedance design measures to be applied to ensure that extreme events above the design standards of the system do not pose adverse impacts. A sequential approach should be applied to the site layout to specifically set aside appropriate location for SuDS.
11 Developer to consult the Recommendations for Site Development Works for Housing areas, CIRIA SuDS Manual and Greater Dublin Strategic Drainage Study for information and guidance relating to the provision of SuDS.
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SuDS should be designed for the lifetime of the development, with suitable provisions for likely future permitted and minor development.
7.5 Planning Guidance
The planning guidance provided in this section aims to assist the decision makers, the Planning Authority and the developer/landowner in finding the path through the differing stages of assessing flood risk issues. The guidance is set out in diagrammatic form as it is not intended to be definitive but rather, indicative of the methodology involved in arriving at a respective conclusion. The guidance is set out for the three stages:
• Decision making (plan making stage), • Planning Authority at assessment of planning application stage, • Developer in making the planning application.
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7.5.1 Decision Making (plan making stage).
Zoning proposal/ recommendation
AVOID Flood Zone C Flood Zone B Flood Zone A
Use Low Vulnerability/ Use Highly Vulnerable Use Highly Vulnerable SUBSTITUTE Water Compatible
No Yes Yes No No Yes
Justification Test JUSTIFY
Passed Failed
MITIGATE Prepare Landuse Strategy
Direct Landuses towards Flood Zone C
or Zone Land Consider low vulnerable uses/water compatible type uses
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7.5.2 Planning Authority at assessment of planning application stage
Development Proposal
Has site been zoned in Development Plan having fully been informed by Sequential Test/Approach and Justification Test
Yes No
Identify Flood Zone Site is located within and vulnerability of landuse type Justification Test (Plan Making) To be undertaken by applicant/developer
Flood Zone C Flood Zone B Flood Zone A Passed Failed
Use Low Vulnernability/ Use Highly Vulnerable Use Highly Vulnerable Water Compatible
No Yes Yes No No Yes
Justification Test (Development Management)
Proposal may not be acceptable on Passed Failed grounds of flood risk.
Proposal maybe acceptable in respect of flood risk – proceed assessment of planning application in relation to other issues.
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7.5.3 Developer in making the planning application
Development Proposal on particular site
Has Site been zoned in Developent Plan having fully been informed by undertaking Sequential Test/Approach and Justification Test
Yes No
Does proposal and site have potential to pass Justification Test
Identify Flood Zone site is located within and vulnerability of land use type
Flood Zone C Flood Zone B Flood Zone A Yes No
Justification Test (Plan Use Low Vulnerability/Water Use Highly Vulnerable Use Highly Vulnerable Making) Compatible
No Yes Yes No No Yes Passed Failed
Justification Test
Consider Alternative Site Passed Failed
Prepare Planning Application & Submit to Planning Authority
Consider an alternative site Or Consider low vulnerable uses/water compatible type uses on site
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8 SFRA Conclusion, Review and Monitoring
8.1 Concluding statement All settlements areas of County Offaly have been examined initially in the context of flood risk. From all of the settlement areas (52 – including Open Countryside) there are 36 settlement areas that warrant further examination and consideration for the purposes of zoning of land and the delineation of development boundaries or envelopes. Table 6.2 identified all of these settlement areas. Table 8.1 below looks at these settlement areas further and summarises how the issue of flood risk has been addressed in the zoning plans for each of the settlement areas identified. It also establishes if any further assessment is required in relation to flood risk and whether further stages of the SFRA are required.
Table 8.1: Flood Risk
Number Settlement Area Name Flood risk and Zoning plans 1 Linked Gateway Tullamore Zoning plan not for inclusion in review of Offaly County Development Plan 2014- 2020. 2 Key Service Town Birr Zoning plan not for inclusion in review of Offaly County Development Plan 2014- 2020. 3 Key Service Town Edenderry Zoning plan not for inclusion in review of Offaly County Development Plan 2014- 2020. 4 Key Service Town Portarlington Zoning plan not for inclusion in review of Offaly County Development Plan 2014- 2020. 5 Service Towns Clara Precautionary approach taken to the zoning of lands for new development. Lands adjacent to River Brosna have been zoned Open Space where undeveloped to provide for low vulnerable uses in recognition of the potential flood risk and in acknowledgement of recurring flood events. Planning Authority to monitor Clara in the context of AFA which is being undertaken as part of CFRAMs. Sequential approach to be adopted to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B. 6 Service Towns Ferbane Precautionary approach taken to the
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zoning of lands for new development. Lands adjacent to River Brosna have been zoned Open Space where undeveloped to provide for low vulnerable uses in recognition of their location. 7 Local Service Town Banagher Precautionary approach taken to the zoning of lands for new development. Planning Authority to monitor Banagher in the context of AFA which is being undertaken as part of CFRAMs. Sequential approach to be adopted to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B. 8 Local Service Town Daingean AFA under PFRA 9 Local Service Town Kilcormac Flood risk to be monitored at this location as flood events inside village occur from inundation from adjoining lands. Site Specific Flood Risk Assessments will be required for development proposals that maybe affected by areas subject to flooding. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding.
10 Village Ballycumber Flood risk to be monitored at this location as flood events inside village occur from inundation from lands outside village. Site Specific Flood Risk Assessments will be required for development proposals that maybe affected by areas subject to flooding. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding. 11 Village Bracknagh Precautionary approach taken to the zoning of lands for new development. Adopting the precautionary approach to flood risk has informed the development boundary of Bracknagh. 12 Village Clonbullogue Precautionary approach taken to the zoning of lands for new development. Lands adjacent to River Figile and
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identified as being in Flood Zones A and B have been zoned Open Space where undeveloped to provide for low vulnerable uses in recognition of the potential flood risk and in acknowledgement of recurring flood events. 13 Village Crinkle Zoning plan not for inclusion in review of Offaly County Development Plan 2014. 14 Village Geashill Flood risk to be monitored at this location as flood events inside village occur from inundation from lands outside village. Site Specific Flood Risk Assessments will be required for development proposals that maybe affected by areas subject to flooding. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding.
15 Village Kinnitty Flood risk to be monitored at this location as flood events inside village occur from inability of infrastructure to deal with rainwater in times of inundation. Culvert has been replaced however, monitoring approach to be applied to appraise in times of heavy or prolonged rainfall.
New development may have to acknowledge the flood risk associated with failure of infrastructure. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding.
16 Village Mucklagh Precautionary approach taken to the zoning of lands for new development. Sequential approach to be adopted to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B. 17 Village Moneygall Flood risk to be monitored at this location as flood events inside village occur from
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inundation from lands outside village. Site Specific Flood Risk Assessments will be required for development proposals that maybe affected by areas subject to flooding. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding. 18 Village Pollagh/Leamanaghan Precautionary approach taken to the zoning of lands for new development. Sequential approach to be adopted to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B. Planning Authority to monitor Pollagh / Leamanaghan in the context of AFA which is being undertaken as part of CFRAMs. 19 Village Riverstown Zoning plan not for inclusion in review of Offaly County Development Plan 2014- 2020. 20 Village Shannonbridge Precautionary approach taken to the zoning of lands for new development. Planning Authority to monitor Shannonbridge in the context of AFA which is being undertaken as part of CFRAMs. 21 Village Shannonharbour AFA under PFRA 22 Village Shinrone Flood risk to be monitored at this location as flood events occur as a result of low lying lands. Site Specific Flood Risk Assessments will be required for development proposals that maybe affected by areas subject to flooding. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding. 23 Village Rahan Precautionary approach taken to the zoning of lands for new development. Lands adjacent to River Clodiagh and identified as being in Flood Zones A and B have been zoned Open Space where undeveloped to provide for low
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vulnerable uses in recognition of the potential flood risk and in acknowledgement of recurring flood events. Planning Authority to monitor Rahan in the context of the AFA which is being undertaken as part of CFRAMs. Sequential approach to be adopted to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B.
24 Sráid Ballinamere Flood risk to be monitored at this location as flood events occur from inability of infrastructure to deal with rainwater in times of inundation. Monitoring approach to be applied to appraise infrastructure in times of heavy or prolonged rainfall. 25 Sráid Brosna Flood risk to be monitored at this location as flood events occur from inability of infrastructure to deal with rainwater in times of inundation. Monitoring approach to be applied to appraise infrastructure in times of heavy or prolonged rainfall. 26 Sráid Cadamstown Amenity area designated adjoining the Sliver River. Sequential approach to be adopted to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B 27 Sráid Clareen Amenity area designated adjoining the Fuarawn River where it flows through settlement. Sequential approach to be applied to ensure that new development is directed towards lands that are at least risk of flooding. Site Specific Flood Risk Assessments will be required for development proposals in areas identified in Flood Zones A and B 28 Sráid Clonfinlough Development Envelope delineated to avoid areas at risk of flooding in particular to the south.
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29 Sráid Dunkerrin Development Envelope delineated to avoid areas at risk of flooding in particular to the south west and north east. 30 Sráid Fivealley Development Envelope delineated to avoid areas at risk of flooding in particular to the south east. 31 Sráid Garryhinch Development Envelope delineated to avoid areas at risk of flooding in particular to the south. 32 Sráid Horseleap Development Envelope delineated to avoid areas at risk of flooding in particular to the west. 33 Sráid Killina Flood risk to be monitored at this location as flood events occur from inability of infrastructure to deal with rainwater in times of inundation. Monitoring approach to be applied to appraise infrastructure in times of heavy or prolonged rainfall 34 Sráid Killyon Development Envelope delineated to avoid areas at risk of flooding in particular to the south. 35 Sráid Tober Flood risk to be monitored at this location as flood events occur from inability of infrastructure to deal with rainwater in times of inundation. Monitoring approach to be applied to appraise infrastructure in times of heavy or prolonged rainfall.
36 Open Countryside Sites to be assessed Site Specific Flood Risk Assessments will individually. be required for development proposals in areas identified in Flood Zones A and B and other areas at risk of flooding. Sequential approach and justification test to be applied to establish the requirement for development proposal in area at risk of flooding.
8.2 SFRA Review and Monitoring
A full update to the SFRA will be required in tandem with the development plan review process. In other respects there are a number of future studies and datasets that must be considered and incorporated into any update of the SFRA or appended to the SFRA to assist in continually informing the development plan in relation to flood risk including:
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• The OPW is preparing flood hazard maps and risk maps for Areas for Further Assessment to be completed by December 2013, CFRAM Draft Maps by 2014 and prepare Flood Risk Management Plans (CFRAMs) by December 2015. • Flood events will need to be recorded from a variety of sources. • Site Specific Flood Risk Assessments will all have to be examined and monitored. • Other datasets including information relating to groundwater flooding from OPW. • Development specific FRAs (various unknown).
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