NUIG Student Accommodation Phase 2 Site-Specific Flood Risk Assessment ...€¦ · Site-Specific...

NUIG Student Accommodation Phase 2

Site-Specific Flood Risk Assessment

February 2019


Site-Specific Flood Risk Impact Assessment

173-124-SSFRA-R3 Page i February 2019

Document Control

Document Number: 173-124-SSFRA

Revision Description Date Prepared Checked Approved

R0 Draft Issue 26/04/2018 Deirdre Ryan Rob Winkel Julie Tiernan

R1 Draft Issue 22/06/2018 Deirdre Ryan Rob Winkel Julie Tiernan

R2 Issued for Planning 12/07/2018 Deirdre Ryan Rob Winkel Julie Tiernan

R3 Re-issued for Planning 26/02/2019 Deirdre Ryan Rob Winkel Rob Winkel



173-124-SSFRA-R3 Page ii February 2019

Table of Contents

Document Control ......................................................................................................... i

Table of Contents ......................................................................................................... ii

1 Introduction .......................................................................................................1

1.1 Background .....................................................................................................1

1.2 Nature of the Proposed Development .....................................................................1

2 Relevant Guidance ...............................................................................................3

2.1 The Planning System and Flood Risk Management Guidelines .........................................3

2.2 Galway City Development Plan (2017 – 2023) ............................................................4

2.3 Land Zoning .....................................................................................................5

3 Flood Risk Identification ........................................................................................6

3.1 Existing Hydrological Environment .........................................................................6

3.2 Topographical & Walkover Surveys .........................................................................6

3.3 Site Geology ....................................................................................................7

3.4 History of Flooding ............................................................................................8

3.5 Review of Existing Surface Water Infrastructure ........................................................8

3.6 Existing Flood Defences ......................................................................................8

3.7 Review of Historic Mapping ..................................................................................9

3.8 Preliminary Flood Risk Assessment Mapping ............................................................ 10

3.9 CFRAMS Mapping ............................................................................................. 11

3.10 Estimate of Flood Zone and Levels ....................................................................... 12

4 Flood Risk Assessment ......................................................................................... 13

4.1 Sources of Flooding ......................................................................................... 13

4.2 Site Vulnerability ............................................................................................ 13

4.3 Climate Change .............................................................................................. 14

4.4 Flood Mitigation Measures ................................................................................. 14

5 Justification Test ............................................................................................... 15

6 Conclusions ...................................................................................................... 16

Appendix A Proposed Site Layout ................................................................................. A-I

Appendix B OPW Historic Flood Events Record ................................................................. B-I

Appendix C Site Visit Images .......................................................................................C-I

Appendix D Existing Services ...................................................................................... D-I

Appendix E PFRA Maps .............................................................................................. E-I

Appendix F CFRAMS Mapping ....................................................................................... F-I



173-124-SSFRA-R3 Page 1 February 2019

1 Introduction

1.1 Background

PUNCH Consulting Engineers were appointed by National University of Ireland, Galway to carry out a Site-Specific Flood Risk Impact Assessment study for a proposed student accommodation development. The assessment is carried out in full compliance with the requirements of “The Planning System & Flood Risk Management Guidelines” published by the Department of the Environment, Heritage and Local Government in November 2009.

The proposed development is located on Upper Newcastle Road, Galway City. The site is bounded to the west, north and east by scrubland and trees and to the south by the Science Research Building and Corrib Village student accommodation. The site is in close proximity to the campus Park and Ride car park, the Institute for Lifecourse and Society Building and the River Corrib. The location of the proposed development is shown in Figure 1 below.

Figure 1: Location of Proposed Development (site boundary indicated in red)

1.2 Nature of the Proposed Development

The project involves the construction of a student accommodation scheme, comprising 125 no. apartments with 674 no. bed spaces, arranged as 85 units of 6 ensuite bedrooms, 4 units of 5 ensuite bedroom and 36 units of 4 ensuite bedrooms, with communal living areas in each unit. Further communal areas and facilities, multi-purpose spaces, ancillary office/reception accommodation, internal plant/service rooms, general storage, refuse storage and a maintenance/workshop area are also provided to service the entire development. The proposed accommodation is arranged in 4 no. blocks with Block A ranging from 4 to 8 storeys, Block B and D extend to 6 storeys and Block C comprises 4 storeys. A commercial/retail space is provided in Block A.




The project also involves proposed changes to the NUI Galway internal road network, including the

provision of an access road with disabled parking and a bus pick-up/drop-off area.

It is intended that the student accommodation units may be used as visitor or tourist accommodation

on a temporary basis outside of academic term times.

The site for the proposed development is currently a greenfield site and is adjacent to the “Park and

Ride” facility and other university buildings.

The proposed site layout is detailed in a series of planning drawings provided by Feilden Clegg Bradley

Studios and PUNCH Consulting Engineers (included in Appendix A of this report).

Figure 2: Site Layout




2 Relevant Guidance

2.1 The Planning System and Flood Risk Management Guidelines

In September 2008, “The Planning System and Flood Risk Management” Guidelines were published by

the Department of the Environment, Heritage and Local Government in Draft Format. In November,

2009, the adopted version of the document was published.

The Flood Risk Management Guidelines give guidance on flood risk and development. The guidelines

recommend a precautionary approach when considering flood risk management in the planning system.

The core principle of the guidelines is to adopt a flood risk sequential approach to managing flood risk

and to avoid development in areas that are at risk. The sequential approach is based on the

identification of flood zones for river and coastal flooding. The guidelines include definitions of Flood

Zones A, B and C, as noted below. It should be noted that these do not take into account the presence

of flood defences, as there remain risks of overtopping and breach of the defences.

Table 1: Flood Zone Designation

Flood Zone Type of Flooding Annual Exceedance Probability (AEP)

Flood Zone A

Coastal Less than a 1 in 200-year (0.5% AEP) event

Fluvial Less than a 1 in 100-year (1% AEP) event

Flood Zone B

Coastal Greater than a 1 in 200 (0.5% AEP) and less than 1:1000 (0.1% AEP) year event

Fluvial Greater than a 1 in 100 (1% AEP) and less than 1:1000 (0.1% AEP) year event

Flood Zone C

Coastal Greater than a 1 in 1000 (0.1% AEP) year event

Fluvial Greater than a 1 in 1000 (0.1% AEP) year event

Once a flood zone has been identified, the guidelines set out the different types of development

appropriate to each zone. Exceptions to the restriction of development due to potential flood risks are

provided for through the use of the Justification Test, where the planning need and the sustainable

management of flood risk to an acceptable level must be demonstrated. This recognises that there will

be a need for future development in existing towns and urban centres that lie within flood risk zones,

and that the avoidance of all future development in these areas would be unsustainable.

A three staged approach to undertaking a FRA is recommended:

Stage 1) Flood Risk Identification – Identification of any issues relating to the site that will require

further investigation through a Flood Risk Assessment;

Stage 2) Initial Flood Risk Assessment - Involves establishment of the sources of flooding, the extent

of the flood risk, potential impacts of the development and possible mitigation measures;

Stage 3) Detailed Flood Risk Assessment - Assess flood risk issues in sufficient detail to provide

quantitative appraisal of potential flood risk of the development, impacts of the flooding

elsewhere and the effectiveness of any proposed mitigation measures.

This report addresses the requirements for Stage 2.




2.2 Galway City Development Plan (2017 – 2023)

Policies relating to flood risk within the Galway City Development Plan 2017-2023 are outlined in Policy

9.3. The relevant excerpt from Section 9. 3 (Flood Risk Assessment) is copied below:

• Support, in co-operation with the OPW, the implementation of EU Flood Risk Directive

(2007/60/EC), the Flood Risk Regulations (SI no. 122 of 2010), the DECLG and OPW Guidelines

for Planning Authorities, the Planning System and Flood Risk Management (2009),

updated/superseding legislation or departmental guidelines and have regard to the findings

and relevant identified actions of the future Corrib Catchment Flood Risk Assessment and

Management (CFRAM) Study, as the study progresses and incorporate these into the

Development Plan, where appropriate;

• Have regard to the recommendations of the Strategic Flood Risk Assessment (SFRA) for the

Galway City Development Plan 2017-2023 in the assessment of development in identified areas

of flood risk;

• Restrict the location of structures other than structures with essential links to the waterway

and public utilities within 10 metres of the River Corrib in G agricultural zoned lands;

• Protect and promote sustainable management and uses of water bodies and watercourses from

inappropriate development, including rivers, streams, associated undeveloped riparian strips,

wetlands and natural floodplains;

• Ensure flood risk is addressed in any future local area plans, framework plans and masterplans

in the city and have regard to the findings of the Strategic Flood Risk Assessment for Three

Local Area Plans 2012 in the preparation of LAPs for Ardaun, Headford Road area, and

Murrough;

• Require a site-specific Flood Risk Assessment (FRA) for planning applications in identified

areas at risk of flooding, where appropriate, in accordance with the recommendations of the

Strategic Flood Risk Assessment (SFRA) for the Galway City Development Plan 2017-2023;

• Facilitate sustainable flood defence and coastal protection works in order to prevent flooding

and coastal erosion, subject to environmental, visual and built heritage considerations;

• Ensure any proposal aimed at alleviating flooding will be subject to Appropriate Assessment in

accordance with Article 6 of the EU Habitats Directive, where appropriate;

• Ensure the use of SUDS, sustainable urban drainage systems, wherever practical, in the design

of development to reduce the rate and quantity of surface water run-off;

• Ensure new development, where appropriate, is designed and constructed to meet the flood

design standards outlined under Section 11.27 Flood Risk Management and the

recommendations of the Strategic Flood Risk Assessment (SFRA) for the Galway City

Development Plan 2017-2023;

• Have regard to the findings of the OPW’s Irish Coastal Protection Strategy Study (2013) of the

west coast;

• Continue to protect the coastal area and foreshore and avoid inappropriate development in

areas at risk of coastal erosion and/or would cause and escalate coastal erosion in adjoining

areas;

• Protect and maintain, where feasible, undeveloped riparian zones and natural floodplains

along the River Corrib and its tributaries.

Objectives

• Where development is proposed in identified flood risk areas under Western CFRAM, the

type or nature of the development needs to be carefully considered and the potential risks

mitigated and managed through on-site location, layout and design of the development to

reduce flood risk to an acceptable level;

• Development shall have regard to the flood resilient design guidance and flood mitigation

measures in the City Council’s Strategic Flood Risk Assessment for Galway City Development




Plan 2017-2023, the recommendations and best practice guidelines of Appendix B –

addressing flood risk management in design of development of The Planning System and

Flood Risk Management Guidelines for Planning Authorities (2009) and the Strategic Flood

Risk Assessment for Three Local Area Plan Areas 2012;

• In identified flood risk areas, Flood Zone A or B, it will be necessary to carry out a Site-

Specific Flood Risk Assessment (FRA), appropriate to the scale and nature of the

development and the risks arising. Proposals shall demonstrate appropriate mitigation and

management measures in the layout and design of development;

• All proposed development must consider the impact of surface water flood risk in drainage

design. Consideration should be given in the design of new development to the incorporation

of SUDS. The drainage design should ensure no increase flood risk to the site or downstream

catchment;

• Development proposals in identified flood risk areas shall consider and incorporate the

potential impacts of climate change and residual risk into development layout and design;

• In areas of identified flood risk all developments including minor works and changes of use

should include an appropriate level of FRA. This assessment must demonstrate that the

development would not increase flood risk in the context of use, emergency access and

infrastructure. Development should demonstrate principles of flood resilient design.

As part of this development plan, a Strategic Flood Risk Assessment (SFRA) was prepared by JBA

Consulting, which was reviewed as part of this assessment. This SFRA recommends that for “residential

buildings within Flood Zone A or B bedroom accommodation is more appropriate at upper floor

levels”.

The report also recommends that flood levels be set above the 1% AEP fluvial level with an allowance

for climate change plus freeboard of at least 300 mm.

2.3 Land Zoning

The land on which the development is proposed is currently zoned as “CF - Community, Cultural and

Institutional” in the Galway City Development Plan 2017-2023. The designation applies to lands “to

provide for and facilitate the sustainable development of community, cultural and institutional uses

and development of infrastructure for the benefit of citizens of the city”. The proposed development is

considered to be in accordance with this land zoning.




3 Flood Risk Identification

3.1 Existing Hydrological Environment

The site is located adjacent to the River Corrib approximately 200 m from the river and downstream of Lough Corrib. It is an area where water levels on the River Corrib are not tidally influenced.

Figure 3: Hydrological environment around the site

A review of the OPW drainage database also identifies benefiting lands to the west and north of the proposed development site (see Figure 5 and Appendix B).

3.2 Topographical & Walkover Surveys

PUNCH Consulting Engineers visited the site on 27th November 2017 and 22nd February 2018 to identify the key drainage and hydrological features of the site, to establish any sources of flooding and to identify any likely routes of flood waters. The findings of the site walkover are presented below:

a) The topography of the site can be described as undulating. Ground levels within the site range from 7.05 mAOD to 13.66 mAOD;

b) The site is currently a greenfield site. There is a large number of trees, bushes and other vegetation present on the site;

c) Open drainage channels are present on site; d) The low-lying northern section of the site is marshy in places.

Key images from the site are included in Appendix C of this report.

A topographical survey of the site was completed by Murphy Surveys on 17th June 2018 and was utilised in this study.




3.3 Site Geology

The geology of the site was reviewed using data from the Geological Survey of Ireland (available at

www.gsi.ie). The location of the proposed development, and the surrounding lands, consist of a

combination of deep well drained and poorly drained. Along the river banks, alluvial minerals are

present which suggests evidence of historical flooding. Figure 4 below shows the geology of the site.

Figure 4: Geology of the surrounding area (source: Geological Survey of Ireland (source: www.gsi.ie))

http://www.gsi.ie/




3.4 History of Flooding

The Office of Public Works (OPW) Flood Hazard Mapping website holds a record of historic flood events.

A review of this database indicated that there have been no instances of flooding in the local area or at

the site of the proposed development (see Appendix B). The maps indicate ‘Benefiting Lands’ to the

North and West (see Figure 5).

Figure 5: Extract OPW Floodmaps Database Report (see Appendix B for full report)

3.5 Review of Existing Surface Water Infrastructure

There is no existing surface water network within the site boundary. There is an existing 600 mm

surface water sewer located on Upper Newcastle Road (see Appendix D).

3.6 Existing Flood Defences

There are no flood defences along this stretch of the River Corrib.




3.7 Review of Historic Mapping

A review of the OSI historical maps was carried out1. The site was not indicated as “liable to flood” in

the available historic OSI maps, however, the northern banks of the River Corrib were indicated as

“liable to floods”.

Figure 6: OSI Historical 25-inch map2

Historic Map 25-inch (1888-1913) maps show a railway line running parallel to the southern bank of the

river. The maps also show rock outcrop at the site, and a ringfort located to the east.

1 Maps available: http://map.geohive.ie/mapviewer.html 2See http://www.myplan.ie/webapp/

http://map.geohive.ie/mapviewer.html

http://www.myplan.ie/webapp/




3.8 Preliminary Flood Risk Assessment Mapping

The Catchment Flood Risk Assessment and Management Study (CFRAMS) is a national programme which

to date has produced a series of Preliminary Flood Risk Assessments (PFRA) which cover the entire

country3, and more detailed flood maps are currently published across the country.

Prior to the publication of the detailed CFRAMS flood maps, a series of Preliminary Flood Risk

Assessment (PFRA) maps were published. These maps indicated preliminary tidal and fluvial flood zones

(which have been superseded by the more detailed CFRAMS maps) along with pluvial and groundwater

risks. The PFRA flood zones are shown in Figure 7 below. Appendix E shows the extents of the PFRA

pluvial and fluvial flood zones in the surrounding area.

Figure 7: PFRA flood zone map indicating extents of fluvial and pluvial flood zones

The PFRA mapping indicates that a portion of the site falls within the extents of Flood Zone B. There

are no areas of land subject to pluvial flooding noted within the site.

It is noted that the PFRA modelling is a high-level study which uses a coarse ground to represent the

topography of the country and does not take flood defences into account. As such PFRA fluvial, pluvial

and coastal flood extents are to be utilised as an initial assessment only.

3See http://www.cfram.ie/pfra/interactive-mapping/ for PFRA maps

http://www.cfram.ie/pfra/interactive-mapping/




3.9 CFRAMS Mapping

As part of the CFRAMS programme, mapping is available online for public viewing, and the local area

has been assessed as part of the Western CFRAMS. The OPW has published detailed flood hazard

mapping for Galway City based on results from the Western CFRAMS. This includes flood extent and

flood depth mapping for a number of return periods for both fluvial and tidal flood events. The CFRAMS

assessment is based on hydraulic modelling of the River Corrib and its tributaries.

Figure 8 below is an extract from the Western CFRAMS fluvial flood map for the River Corrib in area

surrounding the proposed development site. The site is located in an area where the flooding is

influenced by the river levels. Full CFRAMS maps for the area are included in Appendix F.

Figure 8: Extract from CFRAMS fluvial flood map for Galway City (site indicated in red)

As can be seen from the map above, the site of the proposed development is partially located within

fluvial Flood Zone B extents (1 in 1000 year or 0.1% AEP flood zone), while the majority of the site is

considered to be located in Flood Zone C.

The flood levels at the node nearest the site (30CORR00357) are outlined in Table 2.

Table 2: Estimated CFRAMS Fluvial Flood Levels

Node 1% AEP 0.1% AEP

30CORR00357 7.18 7.89




Flood depth mapping shows water depths at the site range from 0 to 1.0 m during a 1 in 1000-year

event, as shown in Figure 9.

Figure 9: Extract from CFRAMS fluvial flood depth map for Galway City (site indicated in red)

The finished floor levels of the proposed buildings range from 9.65 to 9.95 mAOD and therefore, the

proposed development ranges from 1.76 m to 2.06 m above the estimated maximum fluvial flood

levels. Including an allowance for climate change requires flow rates to be increased by 20% for the

Mid-Range Future Scenario (MRFS). No flow rates are available from the CFRAMS mapping however it is

apparent that flood levels increase by 440mm between the 10% and 1% AEP scenarios, and by 710mm

between the 1% and 0.1% AEP scenarios. As such it is considered that increasing the 0.1% AEP by

500mm to represent the climate change scenario is adequate. Under this assessment, accounting for

climate change, there is a minimum of 1.26 m freeboard which is in accordance with the SFRA for the

area (a minimum of 300 mm is recommended).

The location of the proposed development encroaches into Flood Zone B. Due to the location of the

flooding on the site; it is considered that the flood mechanism across the site is storage as opposed to

flood conveyance.

3.10 Estimate of Flood Zone and Levels

PUNCH Consulting Engineers have reviewed the available information as outlined in the above sections.

It is determined that the site of the proposed development partially lies within the extents of Flood

Zone B.

When an allowance for climate change is included as described above, the FFLs are a minimum of 1.26

m above the estimated 0.1% AEP flood levels at the nodes nearest the site including an allowance for

climate change.




4 Flood Risk Assessment

4.1 Sources of Flooding

When carrying out a flood risk assessment, one should consider all potential flood risk and sources of flood water at the site. In general, the relevant flood sources are:

Fluvial Flooding

Fluvial flooding is the result of a river exceeding its capacity and excess water spilling out onto the adjacent floodplain. The site of the proposed development is located adjacent to the River Corrib. However, a review of the CFRAMS maps indicates that the majority of the site is located in Flood Zone C, with a small portion to the north located in Flood Zone B

Pluvial Flooding

Pluvial flooding is the result of rainfall-generated overland flows which arise before run-off can enter any watercourse or sewer. It is usually associated with high intensity rainfall. There are no locations of the site which are noted in Pluvial maps as being at risk of pluvial flooding. The storm network proposed as part of this development has been designed to ensure there is no flood risk to the development from extreme precipitation events.

Coastal Flooding

Coastal flooding is the result of sea levels which are higher than normal and result in sea water overflowing onto the land during high tides or storm surges. The site is located in an area where water levels on the River Corrib in not tidally influenced.

Groundwater Flooding

Groundwater flooding occurs when the level of the water stored in the ground rises as a result of prolonged rainfall. The study is not at risk of groundwater flooding and there is no basement proposed or existing.

4.2 Site Vulnerability

As per The Planning System and Flood Risk Management Guidelines highly vulnerable developments, such as residential properties, located in either Flood Zone A or B require Justification Test. It has been demonstrated in this report that the site is partially located within Flood Zone B, and as such a Justification Test is required.

Table 3: Matrix of vulnerability versus flood zone to indicate Justification Requirement

Flood Zone A Flood Zone B Flood Zone C

Highly vulnerable development

JUSTIFICATION TEST JUSTIFICATION TEST APPROPRIATE

Less vulnerable development

JUSTIFICATION TEST APPROPRIATE APPROPRIATE

Water-compatible development

APPROPRIATE APPROPRIATE APPROPRIATE

There will be some residential units based on the ground floor within Flood Zone B. The finished floor levels of the units in Flood Zone B, 9.65 mAOD, will be well above the 0.1% fluvial flood level including an allowance for climate change and an appropriate freeboard.




4.3 Climate Change

CFRAMS Maps consulted as part of this SSFRA did not show results for the future scenario with climate

change taken into account.

Finished Floor levels will be set at over 1 m above the 1 in 1000-year modelled flood level which will

provide adequate freeboard in the event of a flood greater than the 7.89 mAOD level. It is considered

that the design of the proposed development is sufficiently resilient to the impacts of climate change

on fluvial flooding, as discussed in Section 3.9 above.

4.4 Flood Mitigation Measures

With reference to Section 3.9 above, a review of flood maps produced as part of the CFRAMS indicate

that the site of the development falls outside Flood Zone A fluvial and tidal events, however a portion

of the site falls within the extents of Flood Zone B.

Although the proposed development comprises of student accommodation, the majority of ground floor

residential development will be confined to Flood Zone C. Development in Flood Zone B will comprise

mainly of a plant room and some residential units, however all FFL are set above the Q1000 flood level.

Consideration must be given to emergency access from the proposed development during a flood

event. As Upper Newcastle Road is located in Flood Zone C, emergency access will be maintained

allowing access and egress from the site during a flood event.

The FFL of the proposed development ranges from 9.65 to 9.95 mAOD. There is no proposed basement.

These levels are above the estimated fluvial flood levels of 7.89 mAOD at nodes nearby for a 0.1% AEP

event. The minimum freeboard is 1.76 m for the current scenario, and when making an adjustment for

climate change (500mm for the Mid-Range Future Scenario has been conservatively assumed); this

minimum freeboard is 1.26 m;

The proposed surface water design will limit outfalls to the existing surface water network and results

in no flooding in the network during a 1 in 100-year storm. The proposed development does not

increase the risk of flooding to any adjacent or nearby area;

PUNCH Consulting Engineers also recommend that all infrastructure that would be particularly

vulnerable (e.g. electrical and IT infrastructure, food preparation areas, etc.) be raised above the

predicted 1:1000-year flood level (7.89 mAOD);

PUNCH Consulting Engineers recommend that as part of the site maintenance plan, all future

proprietors inspect all road gullies in the vicinity and report any blockages to the Local Authority

and/or Irish Water. The proprietor should also inspect all surface water drainage within the site, in

particular following heavy rain which may cause debris to obstruct the ACO drain and road gullies.




5 Justification Test

The proposed development comprises of student accommodation. All ground floor residential

development will be above the 0.1% flood level including for climate change and an appropriate

freeboard.

As a Strategic Flood Risk Assessment has been completed as part of the Galway City Development Plan

and the land zoned accordingly, it is considered that Justification Test Box 4.1 has been passed at a

strategic level.

Table 4: Justification Test Box 5.1

Item Response

1.0

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 these Guidelines.

Section 2.3 of this report states that the land is zoned for “Community, Cultural and Institutional”. The proposed development is student housing for NUIG which is in line with the proposed zoning and land use.

2.0 The proposal has been subject to an appropriate flood risk assessment that demonstrates:

2.1

The development proposed will not increase flood risk elsewhere and, if practicable, will reduce overall flood risk.

Run-off from the development will be discharged to a proposed attenuation tank and flows will be discharged to existing drainage at a controlled rate not larger than the greenfield runoff rate for the site. The system will not increase the flow rate to the nearby watercourse. There will be no change in flood risk to the areas downstream of the site (see PUNCH Consulting Engineers Planning Report for further information)

2.2

The development proposal includes measures to minimise flood risk to people, property, the economy and the environment as far as reasonably possible.

Section 4.4 of this document states the mitigation measures.

2.3

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.

There are no existing flood protection measures on the site. There are no residual risks to the proposed development. Emergency access to the development is from the south and there is no access to the development which would be affected by any level flooding from the River Corrib.

2.4

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.

It is PUNCH Consulting Engineers opinion that the proposed development complies with item 2.4. This is discussed in greater detail in other documents submitted as part of the planning application for the proposed development.




6 Conclusions

PUNCH Consulting Engineers were appointed by National University of Ireland, Galway to carry out a

Site-Specific Flood Risk Impact Assessment study for a proposed student accommodation development.

A review of the flooding and flood risk in the area was carried out as the site is adjacent to the River

Corrib.

Flood Maps produced as part of the Western CFRAMS were consulted to establish the outline Flood

Zone. The site is partially located in Flood Zone B, with the majority of the site falling within Flood

Zone C. Flood levels for the area were obtained from the CFRAMS, and the maximum predicted level at

the nodes nearest the site for a 1 in 1000-year fluvial event is 7.89 mAOD.

There will be some residential units based on the ground floor within Flood Zone B. The finished floor

levels of these units (9.65 mAOD) will be well above the 0.1% flood level including an allowance for

climate change and an appropriate freeboard. The FFLs of the proposed development range from 9.65

to 9.95 mAOD. There is no proposed basement. The minimum freeboard is 1.76 m for the current

scenario, and when making an adjustment for climate change (a conservative assumption of a climate

change flood level 500 mm above the Q1000 flood level for the Mid-range future scenario has been

made); this minimum freeboard is 1.26 m.

Consideration has been given to emergency access to the site during an extreme event and access to

the site is in Flood Zone C. The proposed development will not increase the risk of flooding elsewhere

as the proposed surface water network manages run-off arising during a 1 in 100-year storm with no

flooding of the network.



173-124-SSFRA-R3 Page A-I February 2019

Appendix A Proposed Site Layout

FFL: 9.65 FFL: 9.65

FFL: 9.65

FFL: 9.95 FFL: 9.95

FFL: 9.95

FFL: 9.65



173-124-SSFRA-R3 Page B-I February 2019

Appendix B OPW Historic Flood Events Record



173-124-SSFRA-R3 Page B-II February 2019



173-124-SSFRA-R3 Page C-I February 2019

Appendix C Site Visit Images



173-124-SSFRA-R3 Page C-II February 2019

Image 1: From the south of the site facing east

Image 2: From the south of the site facing north



173-124-SSFRA-R3 Page D-I February 2019

Appendix D Existing Services

Galway City Council Water Department

© Ordnance Survey Ireland

Flow Control ValvesNon-returnHydroOrifice PlatePRVPSVOther

Boundary ValvesOpenClosedPart Closed

Non Boundary ValvesOpenClosed

Part ClosedAir Control ValvesWater Stop Valves

Non Boundary MeterMeterGroup SchemeSource

Boundary MeterDistrict (Boundary Meter)

Water HydrantsFire HydrantFire Hydrant/WashoutWashoutTreatment Plant

ReservoirPotableRaw WaterPump StationsWater Network StructuresAbstraction PointKisok

Water FittingsCapOther F ittingWater Distribution ChambersPressure Monitoring Point

Water Mains(Irish Water Owned)Untreated

Potable WaterWater Mains(Non Irish Water Owned)

UntreatedPotable Water

Water Lateral LinesIrish WaterNon IWWater Abandoned LinesWater Casings

February 20, 20180 0.055 0.110.0275 mi

0 0.09 0.180.045 km

1:2,500

"Copyright Ordnance Survey Ireland. All rights reserved.2017/14/CCMA/GalwayCityCouncil."For Non-SLA Local Authority staff use only.

Irish W ate r W e b m ap

Le ge ndStormwater Gravity Mains (Irish Water Owned)

Surfac eStormwater Gravity Mains (Non-Irish Water Owned)

Surfac eStorm Manholes

Cascad eCatchpitHatchb oxLam pholeStand ardOthe r; Unknown

Storm InletsGullyStand ardOthe r; Unknown

Storm FittingsV e nt/ColOthe r; Unknown

Storm Discharge PointsOutfallOve rflowSoakawayOthe r; UnknownStorm Culve rtsStorm Cle an Outs

Sewer Gravity Mains (Irish Water owned)Com b ine dFoulOve rflowUnknown

Sewer Gravity Mains (Non-Irish Water owned)Com b ine dFoulOve rflowUnknown

Sewer Pressurized Mains (Irish Water owned)Com b ine dFoulOve rflowUnknown

Sewer Pressurized Mains (Non-Irish Water owned)Com b ine dFoulOve rflowUnknown

2 / 14 / 2018 1 : 17 : 45 PM

0 0.05 0.10.025 m i

0 0.08 0.160.04 km

1:2,257

© Ord nanc e Surve y Ire land | M ap d ata © Ope nStre e tM ap contrib utors, CC-BY-SA |

Irish W ate r give s this inform ation as to the position of itsund e rground ne twork as a ge ne ral guid e only on the stric tund e rstand ing that it is b ase d on the b e st availab leinform ation provid e d b y e ac h Loc al Authority in Ire land . Itshould not b e re lie d upon in the e ve nt of e xcavations or othe rworks b e ing c arrie d out in the vic inity of the ne twork. Theonus is on the partie s carrying out the works to e nsure thee xact location of the ne twork is id e ntifie d prior to m e c hanicalworks b e ing car rie d out. Se rvic e pipe s are not ge ne rallyshown b ut the ir pre se nc e should b e antic ipate d .

Re pr od uc e d from the Or d nan c eSurve y Of Ire land b y Pe r m ission of theGove rn m e nt. Lic e nse No. 3-3-34

“Gas Ne tworks Ire land (GNI), the ir affiliate s and assigns, ac c e pt nore sponsib ility for any inform ation c ontaine d in this d ocum e nt conc e rninglocation and te c hnical d e signation of the gas d istrib ution and transm issionne twork (“the Inform ation”). Any re pre se ntations and warrantie s e xpre ss orim plie d , are e xc lud e d to the fulle st e xte nt pe rm itte d b y law. No liab ility shall b eac c e pte d for any loss or d am age inc lud ing, without lim itation, d ir e ct, ind ir e ct,spe c ial, inc id e ntal, punitive or c onse q ue ntial loss inc lud ing loss of profits,arising out of or in c onne c tion with the use of the Inform ation (inc lud ing m aps orm apping d ata). NOTE: DIAL BEFORE YOU DIG Phone 1850 427 747 or e -m aild ig@gasne tworks.ie – The ac tual position of the gas/e le ctric ity d istrib ution andtransm ission ne twork m ust b e ve rifie d on site b e fore any m e c hanic ale xcavating take s plac e . If any m e c hanical e xcavation is propose d , hard c opym aps m ust b e re q ue ste d from GNI re gas. All work in the vic inity of the gasd istrib ution and transm ission ne twork m ust b e c om ple te d in ac c ord anc e withthe cur re nt e d ition of the He alth & Safe ty Authority pub lic ation, ‘Cod e ofPractic e For Avoid ing Dange r From Und e rground Se rvic e s’ whic h is availab lefrom the He alth and Safe ty Authority (1890 28 93 89) or c an b e d ownload e dfr e e of charge at www.hsa.ie .”

´



173-124-SSFRA-R3 Page E-I February 2019

Appendix E PFRA Maps



173-124-SSFRA-R3 Page E-II February 2019



173-124-SSFRA-R3 Page F-I February 2019

Appendix F CFRAMS Mapping



173-124-SSFRA-R3 Page F-II February 2019



173-124-SSFRA-R3 Page F-III February 2019



173-124-SSFRA-R3 Page F-IV February 2019

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