Dollymount flood wall review feb 2016 rev2

Dollymount Flood Wall

External Review

Draft Report

Prepared

By

Dr. Jimmy Murphy

MaREI Centre, UCC

February 2016

DollymountFloodWall– ExternalReview 2016

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TableofContentsIntroduction ............................................................................................................................................ 3

Expert Reviewer Profile........................................................................................................................... 4

Site visit. .................................................................................................................................................. 4

Public Input ............................................................................................................................................. 4

Design Assessment .................................................................................................................................. 4

Extreme Water Levels ......................................................................................................................... 4

Sea Level Rise (SLR) ............................................................................................................................. 6

Wave Conditions ................................................................................................................................. 7

Minimum Freeboard ......................................................................................................................... 12

Recommended Wall Level .................................................................................................................... 12

Alternative Wall Solutions .................................................................................................................... 12

Demountable barriers ....................................................................................................................... 13

Glass Walls ........................................................................................................................................ 13

Increase Road Levels ......................................................................................................................... 14

Water Level Control .......................................................................................................................... 14

Modify Design Criteria ...................................................................................................................... 14

Crest Re‐design ................................................................................................................................. 14

Conclusion and Recommendation ........................................................................................................ 15

Documents and correspondence reviewed .......................................................................................... 16

Appendix 1 – Review Brief .................................................................................................................... 18


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IntroductionThis review of the wall height of the Dollymount promenade was carried out to assess if the current

crest level of 4.25m ODM (Ordnance Datum Malin Head) is appropriate for this location. A number

of documents relevant to the promenade design and the determination of extreme values for the

Dublin Bay area were assessed in this review. A listing of all documents, communications,

presentations etc used in this review are listed at the end of this report.

The basis of design of the wall was to protect against a two hundred year event in relation to water

levels and winds in Dublin Bay and to provide a level of safety against anticipated sea level rise. The

final height of the wall is made up of 4 components as shown in figure 1 [7]. The initial designed

level was 4.6m ODM however this was reduced to lessen the visual impact. The resultant wall height

of 4.25m ODM is considered an interim solution which may, depending on the rate of sea level rise,

need to be increased to the original designed values in the future. In relation to the existing

defences the new wall height ranges from being equal in height to being at a maximum 0.85m higher

than existing defences. The impact of the increased height is minimal to pedestrians and cyclists

using the promenade and slightly restricts views of the lagoon from the footpath on the St Annes

Park side. It does however restrict views in places from standard cars travelling along the road.

The primary issue of public concern is in relation to the height of the wall, that it is not in line with

other flood defences in Dublin and it obscures views of Bull Island. The analysis carried out in this

review only considers the appropriateness of the design decisions made in terms of the wall height

and examines other options to provide the same level of protection. No comment is made about

any other flood scheme in the Dublin area as that is not part of the current remit.

Figure 1 Designed wall Configuration [7]


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ExpertReviewerProfileDr Jimmy Murphy is a senior Research Engineer in the MaREI Centre in University College Cork and

has over 20 years experience in marine projects in relation to the design and evaluation of coastal

and harbour structures. This work involves the use of such tools as physical model testing,

numerical modelling and field measurements to optimise the layout and design of marine structures.

He lectures in the School of Engineering in UCC on the subjects of Environmental Hydrodynamics

and Harbour and Coastal Engineering. In addition he supervises a number of PhD and masters

students and has a number of publications in the areas of coastal engineering and ocean energy.

Sitevisit.A site visit took place on Friday 18th December 2015 where in the presence of Mr. Gerard O’Connell

from Dublin City Council (DCC) the promenade scheme and the wall design were explained. Where

access was available we examined the wall and drove along the section of road most affected by its

construction. We also visited the Bull Island biosphere via both the causeway and wooden bridge

and generally discussed flood defence levels in the local area and the impacts of previous extreme

events. This visit clarified the issues in relation to the visual impacts and the flood defence

requirement.

PublicInputI have reviewed officially submitted documents from the public ([15] and [16]) as well as kept in

touch with media reports ([18], [19] and [20]) while working on this review. This has highlighted to

me the importance of this issue to the local community and the connection they have with the

physical environment. Thus I feel that I am aware of the significant public concerns in relation to the

flood wall although many issues raised are outside the remit of my review (as outlined in Appendix

1), which focuses on the engineering justification for the current wall height. After submission of

this draft report it is planned that I meet with DCC and public groups and subsequently finalise the

document.

DesignAssessmentThis section considers each of the elements that determine the wall height. I should state to begin

with that even though all the relevant information was available, I did not find a clear consistent

design document and the information provided, as used to determine the wall height, sometimes

differed between documents, i.e. [4] and [7].

ExtremeWaterLevelsThe extreme water levels are the most dominant component in terms of determining the wall

height. In Figure 1 this has a value of 3.2m ODM (in this report I will only use Ordnance Datum Malin

as the reference for the vertical datum) which represents the 200 year return condition. Extreme

water levels are made up of a combination of astronomical and meteorological (surge) components,

the former can be predicted well in advance whilst the latter is dependent on the weather. If the

astronomical component is first considered it can be seen from Figure 2 (column labelled mODM)

that the design water level for the wall is 1.21m higher than the highest astronomical tide (HAT).


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This indicates that there is a high surge component to the water levels in Dublin Bay and this is

borne out by the number of extreme water levels in recent years. The 2002 event had a water level

of 2.97m ODM twhich was the highest ever recorded water level up to that point whilst the tide of

3rd January 2014 reached a recorded level of 3.014m ODM at Alexandra basin in the Docklands with

unconfirmed information of a level of , 3.047m ODM at Dollymount. A study undertaken by Royal

Haskoning [9] after the extreme event of 2002 showed that the 200 year event had a value of 3.13m

ODM which differs slightly from the value indicated in Figure 1. A re‐evaluation of extreme levels in

2015 [5] using the most up to date data showed that the magnitudes were largely unchanged.

However when taking account of sea level rise in the period between 2003‐2015 and more accurate

tide level data there is an adjustment of the 200 year water level to 3.25m ODM. This is stated as

follows in [5];

The residual mean water level of the tidal analysis gives an indication of the changes in

Mean Sea Level (MSL) that have occurred over the years. Based on the additional tide

gauge data, an increase of 0.13m was observed in the last 13 years (Svasek Hydraulics

2015)

Although the analysis has shown that to date in Dublin the extreme water levels are stable there is a

risk that they could change due to climate influences. Changes in storm duration, intensity and

frequency as well as sea level rise can contribute to surge levels increasing and this has been

highlighted by the IPCC. The text below is taken from [14].

In summary, dynamical and statistical methods on regional scales show that it is very likely

that there will be an increase in the occurrence of future sea level extremes in some regions by

2100, with a likely increase in the early 21st century. The combined effects of MSL rise and

changes in storminess will affect future extremes. There is high confidence that extremes will

increase with MSL rise yet there is low confidence in region‐specific projections in storminess

and storm

Gregory [13] also concludes that

It is very likely that there will be a significant increase in the occurrence of future sea level

extremes.

It is not suggested that any change be made to the extreme values due to possible future changes

but in terms of the wall height the freeboard allowance can incorporate this risk.

The 200 year design criterion for coastal flood defences is standard for Ireland and I am satisfied that

the data available and methods of analysis used were satisfactory for determining the level to be

used for the flood defence wall. The most relevant value to use in this case would be 3.25m ODM

and not the 3.13m ODM or the 3.2m ODM values that are indicated in some documents ([4] and [7]).


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Figure 2 Dublin (North Wall) Tidal Levels [4]

SeaLevelRise(SLR)There are no fixed rules in terms of the application of a sea level rise allowance in the design of

coastal structures in Ireland. I have experience from various projects where values chosen range

from 0 – 1m with the most common value used being 0.5m. The choice is determined by what the

client or the design engineer considers to be the most appropriate. There is a lot of uncertainty in

terms of the long term rate of SLR but best estimates from the IPCC research indicate that it is very

likely that the 21st‐century mean rate of SLR will exceed that of 1971‐2010. Figure 3 indicates

possible SLR based on different climate parameters. Given that there is clear evidence that sea

levels are rising and for Dublin Bay, taking land submergence into account, the rate is greater than

4mm/year it is important that an allowance be made in any flood defence design.

In 2011 the OPW issued guidelines whereby a sea level rise of 0.5 metres could be used when using

Mid‐Range Future Scenario (MRFS) and a sea level rise of 1 meter for High End Future Scenario

(HEFS) [5]. In relation to Dublin Bay the Roughan O Donovan report [4] base the sea level rise

allowance on the findings from the Intergovernmental Panel on Climate Change (IPCC, 2007). A

recommendation for sea level rise of 0.4m is used for the year 2100. Therefore the combination of

sea level rise and extreme water levels taken from [4] gives a value of 3.53m ODM which is lower

than the value of 3.7m ODM taken from Figure 1. The Royal Haskoning report [5] provide a

combined value of 3.76m ODM.

My assessment for a design horizon up to 2100 and using a 200 year extreme level of 3.25m ODM

(which includes SLR up to 2015) is that a value of 0.4m for SLR would be appropriate. This

corresponds to an average sea level rise of about 4.7mm/year which is higher than the current rate.

Combining the extreme water level with sea level rise gives a total water level of 3.66m ODM. This

value is broadly in line with the value provided in Figure 1.


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Figure 3 Sea Level Rise Trends [13]

WaveConditionsThe analysis of wave conditions for the determination of design conditions was not fully clear so I

carried out a separate analysis which will be presented in this report. The Roughan O Donovan

report [4] indicate that given the restricted nature of the fetch (distance over which the wind blows)

and the shelter provided by local topography it is likely that the 1 year return significant wave height

(Hs) values along the Dollymount frontage to be of the order of 0.47m with a potential maximum

wave height of 0.8m . My assessment would be that such wave magnitudes are very high in relation

to the length of the fetch and may not consider that direction of propagation as this has a significant

influence on how the waves interact with the flood defence. For instance the highest waves are

likely to be generated along the longest fetch which is orientated in a circa SW‐NE direction. Waves

propagating in this direction will be confined by the wall but will not break or reflect from it. This is

different from waves generated from easterly winds which are directly incident on the wave wall but

are likely to be much reduced in height due to the shorter fetch. The analysis to clarify the wave

conditions incident on the wall used two different sets of empirical formulae for determining the Hs

and Tp (peak wave period). The first method is as outlined in the Coastal Engineering Manual whilst

the second formulation was developed by Donegan and Walsh.

Input information includes wind speed, fetch length and water depths and which this information

the design wave conditions on the wave wall can be is determined. In this analysis three wind

directions were considered as can be seen from figure 4‐6. The fetch lengths used in each case are

shown in these figures and in the analysis the average water depth over the fetch for a 3.66m ODM

water level was chosen as 3.0m. Also I used the same wind speeds for all directions as used by [4]

even though there are slight variations that I considered not to be significant. I should note that


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there is a high level of uncertainty regarding determining the wave conditions in such enclosed and

restricted short fetches and some wave measurement would be very useful.

If waves that propagate towards the wall are first considered (Table 1) then it can be seen that the 1

year significant wave height (corresponding to the 18.2m/s wind speed) is of the order of 0.3m with

an associated wave period of 1.7s. These waves are relatively minor in terms of their size and do not

represent a major loading on the wall structure. The manner in which these waves interact with the

wall is important as because they are low in height and short in length they will not break against the

wall but reflect from it. Therefore overtopping from wave breaking should not generally occur for

this structure although it would be likely that the high wind speeds would lead to whitecapping of

the waves. Previous physical model testing on vertical structures that I have undertaken indicated

whilst the waves are largely reflective occasional breaking can occur that can lead to overtopping.

When a non breaking wave interacts with a vertical wall a standing wave can be established in front

of the structure which means that wave oscillations at the wall increases and are doubled in many

cases (known as clapotis). Therefore instead of the water level oscillating around the mean level by

0.15m (for a 0.3m wave) it now oscillates with an amplitude of 0.3m. Therefore a minimum of 0.3m

is required to be added to the wall height to ensure that water does not consistently overtop the

structure. This allowance is also sufficient to cater for waves propagating along the length of the

lagoon as their maximum height of 0.47m (Table 3) results in an amplitude of oscillation of 0.235m.

Table 3 also shows that the causeway experiences the largest waves generated in the lagoon.

Therefore the recommended allowance for wave action on the wall is 0.3m


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Figure 4 Fetch length 1 [11]

Table 1 Calculated Wave Conditions for fetch 1

CEM Donegan

Wind SpeeDepth (m)Fetch (m) Hs (m) Tp (s) Hs (m) Tp (s)

18.2 3 833 0.29 2.06 0.30 1.71

23.4 3 833 0.39 2.25 0.38 1.89

27.3 3 833 0.47 2.37 0.45 2.01

29 3 833 0.51 2.42 0.48 2.06

30.7 3 833 0.54 2.46 0.50 2.11

32.9 3 833 0.59 2.52 0.54 2.16


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CEM Donegan


18.2 3 671 0.26 2.06 0.27 1.60

23.4 3 671 0.35 2.25 0.34 1.77

27.3 3 671 0.42 2.37 0.40 1.88

29 3 671 0.46 2.42 0.43 1.93

30.7 3 671 0.49 2.46 0.45 1.97

32.9 3 671 0.53 2.52 0.48 2.03


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CEM Donegan


18.2 3 2040 0.45 2.06 0.47 2.23

23.4 3 2040 0.61 2.25 0.60 2.47

27.3 3 2040 0.74 2.37 0.70 2.63

29 3 2040 0.79 2.42 0.74 2.69

30.7 3 2040 0.85 2.46 0.79 2.75

32.9 3 2040 0.93 2.52 0.84 2.83


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MinimumFreeboardFreeboard is required to provide a level of safety in the design particularly when there is uncertainty

regarding input values that were used. The application of safety factors is standard engineering

practice so it is justifiable to use them for the wall design. In this case the main uncertainty relates

to the determination of the design wave conditions and their interaction with the wall. Examples of

uncertainties are provided below;

Given that the wind speed used to generate the wave conditions is the average hourly value

and the short length of this fetch would indicate that the 10 minute wind speed would be

more appropriate to use. Therefore wave conditions are expected to be slightly higher than

indicated.

The exact nature of wave interaction with the wall is dependent on a number of factors that

cannot be fully quantified. In this case field monitoring should be carried out and also

physical modelling testing in order to better understand what is happening.

Uncertainty regarding extreme water levels as previously outlined

I consider a value of 0.3m freeboard as used in the design to be appropriate. Generally in exposed

coastal locations higher freeboards are required mainly to cater for wave action. Given that wave

conditions are benign in the lagoon and the type of wave interaction with the wall this level of

freeboard is acceptable.

RecommendedWallLevelThe overall assessment of the wall height is made up of the following components

Extreme water level (200 yr) 3.25m

Sea Level Rise 0.4m

Wave Action 0.3m

Freeboard 0.3m

Total Height Required 4.25m ODM

Therefore I consider the selected wall height of 4.25m ODM to be appropriate in terms of the

criteria set out for the design. It is interesting that even though the components that makeup the

wall height in this review differ from the design the overall value remains the same.

AlternativeWallSolutionsThe previous analysis indicates that the currently designed wall height is justified based on the

information on various analyses of the extreme conditions and the design criteria that was used.

This section outlines possible alternative solutions that would not have the same visual impact but

would in general provide the same level of protection from flooding. It would be the intention that

such solutions if implemented will be applied along a 450m section of the road where the maximum

increase in wall height is 0.69m. The introduction of these options is not a recommendation for their

use as each would require full design and planning.


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DemountablebarriersDemountable barriers are a well proven solution and have been successfully used in a number of

flood schemes in Ireland. There are a number of different types of solutions and a design study

would be required to determine which would be most appropriate for this site and how it could be

incorporated into the existing structure. These barriers would need new planning permission and

the costs would be relatively high as they would need to include modifying the existing wall,

purchasing the barriers and providing a storage location. Also their erection would require

significant resources during a flood event from DCC as this scheme would double Dublin’s total

length of such barriers.

GlassWallsConstructing all or part of the wall using glass panels has been suggested as a potential option to

preserving the views from the road. To date glass walls have been used primarily in riverine and

sheltered estuarine locations and there are examples in Germany, UK and Ireland with the

Waterford City Flood Alleviation Scheme the most commonly referenced site in Ireland. There is no

doubt that glass panels could be designed to work for the Dollymount site even though there is

limited knowledge as to how they would behaviour when subject to regular wave action. Although

this should not really be an issue as, if only the top 0.5m of the wall was glass then wave action at

this level would be rare. There are other factors that should be taken into consideration in relation

to glass walls and these include

Cost – The overall cost of glass panel system can wary depending on the particular

application but figures up to €5k per linear meter have been suggested.

Maintenance – They would require regular cleaning

Possible Vandalism in the form of breaking and graffiti

Environmental impacts – it is possible that reflections and glare from the glass may have a

negative impact on this sensitive costal ecosystem and this would need to be investigated.

Figure 7 Glass Floodwall in Waterford City [10]


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IncreaseRoadLevelsThis relatively simple solution would involve raising the road level such that the views from the road

would be at least partially restored. Given an average eye height for car drivers as being 1.1m then

the road level would need to be above 3.15m ODM to enable views beyond the wall. DCC state that

this option has been already assessed at an area Committee briefing and it was estimated that it

would cost of the order of €0.5m which was considered to be impractical.

WaterLevelControlThis solution would involve controlling the level of water entering the Dollymount lagoon by

constructing a barrier type structure at the Dollymount bridge location. This would be activated

during extreme events and would prevent waters from reaching high levels in the lagoon and so

reduce the required height of the wall. Such a scheme would be expensive, require planning and

potentially be disruptive to the existing natural environment so is unlikely to be a feasible

alternative.

ModifyDesignCriteriaAn important point relates to the use of the 200 year condition in the design process. This is a very

extreme value and a level that has never been recorded in Dublin Bay in over 90 years of records. I

queried DCC regarding the use of this return period in this case. For instance the 100 year extreme

water level is 0.1m lower and if used would have a positive impact in terms of the visual aspects.

DCC responded by stating that their advice from the OPW is that coastal flood defence designs as

undertaken by them should be to the 200 year return period and this is in line with all recent

schemes designed in Dublin. Their view is that damages from tidal flooding are generally

significantly worse than river flooding for a number of reasons including associated wave action, salt

water content, ground water contamination, overloading of combined sewer networks, etc.

A 200 year design event could occur due to a number of different combination of events – the

design case chosen used the 200 year water level with the 1 year wave height as this was found to

give the most severe loading on the structure with respect to flood risk. But other cases studied

included the 10 year water level with 10 year wave condition and the 50 year wave with 1 year

water level [4]. These obviously would have a lesser impact in terms of the height of the wall but as

is standard engineering design practice the most severe condition was chosen. My view is that the

water level should be the dominant criteria as wave conditions are relatively benign at this site. The

Roughan O Donovan report [4] does say that the design horizon of the wall is 2100 and from which

sea level rise adjustment values were determined. Given that this is the case it should be assessed

whether a 100 year design condition could be used instead of the 200 year.

The other option for modifying the design criteria is in relation to the sea level rise allowance. Given

that measured water levels as recent as 2014 were above 3.0m ODM there may be more scope in

reducing the 0.4m allowance then changing the 200yr extreme level design. Therefore if the SLR

element of the wall height was reduced by between 0.1‐0.2m and DCC carried out frequent reviews

based on extreme water levels and sea level rise rates then this could provide a solution.

CrestRe‐designIt was stated previously that waves will not consistently overtop the wall during a storm event but it

will occur occasionally. The current crest design is not optimum for minimising overtopping and


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could be modified. Figure 8 below shows the type of crest configuration that is often used in coastal

structures to reduce overtopping volumes and it may be possible to shape the capping piece of the

Dollymount wall in this manner. This would improve the performance of the wall against wave

action and could delay the ultimate planned increase of the wall to 4.6m ODM.

Figure 8 Example of Crest Detail for vertical wall [12]

ConclusionandRecommendationThe analysis that I have carried out show that the current wall height (4.25m ODM) is justified based

on the design criteria used even though the components that make up this height differ slightly from

indicated values.

This still leaves the issue with regards to the loss of visual amenity and in this review I have

suggested a number of solutions. The majority of solutions considered have significant implications

in terms of costs, planning requirements and environmental effects and would be unlikely to resolve

the immediate issue. Therefore the recommendation that I would make is that DCC review the

design criteria and in particular the SLR allowance included in the design. My suggestion is that a

value in the range of 0.2‐0.3m be used (instead of 0.4) which would mean that by current mid range

SLR scenarios the wall height should still be sufficient to provide flood protect for at least 50 years.

This proposed adjustment of the wall height should only be applied at locations where the visual

amenity is most affected as agreed between DCC and local groups. If this solution is implemented

then DCC would need to frequently review both extreme water levels and sea level rise rates and

have a plan in place for increasing the wall height to ensure that there is a sufficient level of flood

protection.


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DocumentsandcorrespondencereviewedI have listed below all documentation that was made available to me by DCC plus additional items

that I used as part of the review.

[1] Dollymount Promenade and Flood Protection Project ‐ Historic Evolution and Geomorphologic

Assessment (2009)

[2] Dollymount Promenade and Flood Protection Project; Historic Evolution and Geomorphologic

Assessment, Roughan O'Donovan / Dublin City Council, 21 September 2009, Final Report

[3] Dollymount Promenade and Flood Protection Project; Hydrodynamic Modelling Report,

September 2009, Final Report, 9T3615

[4] Dollymount Promenade and Flood Protection Project ‐ Coastal and Flood Risk Engineering Design

Criteria Report, Roughan O'Donovan / Dublin City Council, September 2009, Final Report, 9T3615

[5] Clontarf ‐ Task1 ‐ Wave Transformation Report, Royal Haskoning, 27 August 2015, RDCR001D01,

[6] Dollymount Flood Alleviation Project, Briefing Notes, Prepared by Gerard O Connell, 29th Oct

2015

[7] S2S Cycleway & Footway Interim Works (Bull Road to Causeway Road), Presentation to Elected

Members, 11th November 2015

[8] Greater Dublin Strategic Drainage Study, Regional Drainage Policies – Volume 5 Climate Change,

March 2005

[9] Dublin Coastal Flooding Protection Project, Final Report Volume 1 ‐ Main Report, Royal

Haskoning, April 2005

[10] Waterford City Flood Alleviation Scheme, Gavin O’Donovan, BE CEng MIEI, Associate, RPS

Consulting Engineers Ltd, (Paper first presented to Engineers Ireland on 12th Feb 2014)

[11] Google Maps

[12] EurOtop; Wave Overtopping of Sea Defences and Related Structures: Assessment Manual, Jan

2007, SSN 0452‐7739, ISBN 978‐3‐8042‐1064‐6, http://www.overtopping‐manual.com/eurotop.pdf

[13] Projections of sea level rise, Presentation by Jonathan Gregory, Lead author, Chapter 13, Sea

level change IPCC, https://www.ipcc.ch/pdf/unfccc/cop19/3_gregory13sbsta.pdf

[14] IPCC Report (2013) Chapter 13 Sea Level Change,

https://www.ipcc.ch/pdf/assessment.../WG1AR5_Chapter13_FINAL.pdf

[15] Morrissey Family Letter to Dublin City Council ‐ 29th October 2015

[16] Follow up Note to Dublin City Councillors re Sea Protection ‐ Height Survey (John Morrissey)

[17] Frequently Asked Questions_Version 2_30th October 2015


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[18] http://www.irishtimes.com/news/environment/residents‐say‐clontarf‐sea‐wall‐construction‐

must‐be‐stopped‐1.2409083

[19] http://www.clontarf.ie/news/sea‐wall‐update‐letter‐to‐dcc‐from‐local‐representative‐groups

[20] http://www.herald.ie/news/deluge‐of‐complaints‐for‐councils‐berlin‐wall‐on‐the‐clontarf‐road‐

34395037.html


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Appendix1–ReviewBrief

Final Draft

Re: Dollymount Flood Wall – External Expert Brief.

Following unanimous approval of a motion by Dublin City Councillors at an emergency meeting of the Council on Wednesday 11th November last (copy attached) it has been decided to procure a external expert to independently assess the height of the partially constructed and proposed new sea wall along Clontarf Road and James Larkin Road between the Wooden Bridge and the Causeway to Bull Island, Clontarf, Dublin 3.

Representations from members of the public who drive past this new wall contend that it obscures their views of Bull Island thus requesting this review. Attached are frequently asked questions and links to the City Councils web-site which outline the history of the project so far and some of the main issues queried by local and regional residents.

The brief for this external expert includes the following:

1. Site visit. Meeting with Environmental Monitoring Group.

2. Review previous reports which include this section of flood defence and the latest relevant national/international best practice documents on climate change with a view to verifying and/or establishing relevant design criteria. This shall include but not be limited to:- Greater Dublin Strategic Drainage Study (GDSDS) Climate Change

Policy Document No.5 adopted by Dublin City Council. Dublin Coastal Flood Protection Project. SAFER Project. Clontarf Promenade Wave Modelling Projects. Dublin Bay tide gauge records with particular attention to Sea level

rise noted between 2000-2014. An Bord Pleanala Decisions & Inspector’s Reports for this stretch of

wall.


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Part 8 approval by Dublin City Council for this cycleway, watermain and flood wall.

National/International best practice on guidelines and recommendations on current and future flood defence heights.

Eastern Region CFRAMS reports and draft CFRAM floodmaps. Irish Coastal Flood Protection Strategy (ICFPP) – OPW. Review of international best practice on design of coastal

defences/flood defences and climate change. Other reports/analysis which the expert deems necessary.

3. Analysis and recommendation on the four main constituents which make up the height of this flood wall.

Static tide design level (appropriate return period and associated level),

global warming element (temporal allowance and appropriate sea level rise allowance(s) for same)

associated wave defence component (based on wave climate in lagoon and overtopping of flood wall),

freeboard allowance (if any required).

4. Assessment of the suitability of a glass wall option for the highest portions of the proposed new wall.

5. Draft report in 3 weeks with final report in 4 weeks. The report will outline all reports and studies read by the expert, his/her conclusions from them and his/her analysis and recommendation in respect of the height of the coastal flood defence wall required for this section of Dublin City coastline, i.e. adequacy of the existing design or proposed new design level.

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