Resilience to the Rise - Scenarios of Climate Change and Sea Level Rise: Reducing the Risk of Coastal Flooding in South Dublin Bay

Analysis of Focus Area

Topography and Bathymetry Map High and Mid Coastal Flood Extents with Sea Level Rise

Context Map 4

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3 10 Coastal flooding Sandymount, Dublin 2017 (Dublin City Council)

The central focus of the South Bull Dublin Bay interventions is to design a flood resilience protection system with multiple benefits for people and nature. This 100 2 -year plus proposal takes into account the expected effects of climate-change induced sea level rise. It examines a variety of strategies to promote resilience for 4 3 bordering communities areas of Merrion, Sandymount, Irishtown and Poolbeg in south Dublin Bay. This area is an important home for wildlife and a major recreational 5 6 0 -0.3

asset within the capital city of Dublin. 7

8 -0.2 0.1 - Evolution of Dublin Bay 9

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-0.1 Construction of the Great -0.2 -0.1 South Wall (1715-1730) and 20 the North Bull Wall (1815-1823) resulted in the development of a safe harbour for Dublin. It also marked the beginning of a dramatic change to the shape and features of the bay Most of the topography by the shoreline and Poolbeg peninsula are constructed from reclaimed and man Medium Probability flood events have approximately a 1-in-a-200 chance The South Bull in south Dublin Bay is the site made ground. Historically, the fill consisted of seabed dredgings and domestic waste. It was municipal do- of occurring or being exceeded in any given year. Annual Exceedance Probability (AEP) of 0.5%. such that the formation of location and the focus area for this analysis. mestic landfill site until 1978. Bull Island was already well High Probability flood events have approximately a 1-in-a-10 chance underway by the late 19th South Bull is a shallow bay with an extensive tide distance. When the tide is out, the waters edge is some of occurring or being exceeded in any given year. Annual Exceedance Probability (AEP) of 10%. 3km from the shoreline by the martello tower, Sandymount. century.

The transformation over past Meteorology & Hydrology Extreme Weather Events Past 35 Years Tides and Currents Tides and Sea Level Rise centuries is overshadowed by the changes over the past Dublin Average Annual Sea Level Rise 2000 - 2016 hundred years, with more than 440 hectares of infill since 1925: 250 hectares on the north side and 190 hectares on the south of the River Liffey. Recent climate related events seem a portent of continuing change

in the evolution of Dublin Bay. The recorded average sea level rise in In 2002, the water level in the Dublin Bay, between 2000 and 2016, was 6-7 mm per year (DCC, 2018), This Irish Sea triggered emergency graph charts the average sea level rise IPCC 2003 over this period and compares it to the flood prevention measures in IPCC global trend. the city.

Tha last three maps shown to Tidal Flow - Flood Tide (low to high tide) from South to North the left, show these projected changes, and include the Climate Trend Graphs - Ireland interventions proposed in this project.

KEY Annual Rainfall (1941-2010)

Mean Surface Air Temperature (1900-2011)

(Source: EPA / Dwyer) Dublin Airport Wind Trends (1944-2010) Tidal Flow - Ebb Tide (high to low tide) from North to South

Typology of Coastal Edges

Seapoint

Typology Edge - Natural

Rocky habitat Martello Tower - Cross Section of South Dublin Bay

High Tide

Low Tide

Scale : A

Natural - Rocky Habitat - Seapoint Natural - Sandy Habitat - Merrion Artificial - Sea Wall - Poolbeg Artificial - Sea boulders Defence - Poolbeg

Ciaran Rooney 16731989 LARC 40360 - Review no. 5 - Exhibition 18th May 2020 MASTERPLAN

INTERVENTIONS TO REDUCE THE RISK OF COASTAL FLOODING

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6 PHASE I - YEAR 2020 - 2075

1 Design Thesis Research Question: Recreation Pier Resilience to the Rise 1 Facilitating activities with a focus on watersports. The Pigeon House pier would 8 Scenarios of Climate Change and Sea Level Rise: Reducing the Risk of Coastal be for leisure and social use - kayaking – kite surfing – SUP (Stdand up paddling) 7 2 Flooding in South Dublin Bay Rockclimbing walls 5 Café 9 The central focus of this project at South Bull Dublin Bay is a flood resilience Seasonal Restaurant protection system with multiple benefits for people and nature. These Sports Performance space and education centre interventions, while reducing coastal flood risk, will become a sautoir of 2 Upgrade with additional planting and widening of the pedestrian path from the blue green spaces on the theme of outdoor life. To combat the increased Poolbeg SDZ (strategic development zone) to Irishtown Reserve Park levels of flooding and habitat destruction that are expected, these plans

for intervention through the remainder of this century is informed by 3 Construction of living breakwaters with Ecocrete blocks x 5 considerable research, and envisions new landforms, living breakwaters,

and grassy berms to contribute to a long-term strategy of protection, 4 Construction of Phase I Poolbeg SDZ resilience, and renewal. 5 Reintroduction and restoration of oyster reefs (with possibility of expansion)

3 An expanded promenade and esplanade at Sandymount links its all together and allows people to experience maritime leisure and pursuits at 10 a really close range. Five hard-programmed social and ecological nodes, PHASE II- YEAR 2075-2125 all in different ways linked to the theme of flood resilience and protecting 6 Construction of PHASE II Poolbeg SDZ the coastal habitats of this beautiful UNESCO Biosphere.

7 Extension of Sean Moore Park, Ringsend Construction of Bicycle and pedestrian access link for Sandycove to Sutton route

New 23 hectare reclaimed land for 8 Phase III of Poolbeg SDZ With Central plaza area

9 Construction of Sea Defence 11 – Revetment steps with access to strand

10 Widen and extend by 1.5 km the Sandymount promenade between 25 and 50 metres reclaimed from the coastline with berms situated where flooding is prone and as 13 a sea defence measure. This promenade will connect to Sean Moore Park and Poolbeg Plaza and onwards.

Park areas Nature Areas Cafes Amenity space

11 New waterfront piers with nature learning centre, swimming baths, outdoor cinema, social space, performance space

12 Extension of cycleway to Blackrock on coastal side

PHASE III- YEAR 2150 Onwards

13 The dashed line is the projected growth and development of the South Bull Spit. It is evisaged that by this time, it would be nearly 3km long.

William Bligh map (1803) of Dublin Bay This 2D model of site help to visualise the chamges to the shoreline and sedimentation processes over time The spit growing at Merrion Gates is the genesis of a dynamic natural process that will culminate in the South Bull Island, like North Bull Island. From historic maps you can trace the beginning of Bull Island, in fact it started out as a litte dry sand bank on the North Bull. One day if left to nature that in 200 years from now, we could have a South Bull Island.

‘Berges de Rhône’ revetment steps, Lyon, France Hastings Pier, Hastings, England St. Pete’s Pier, St. Petersburg, Florida, USA Swimming baths, Helsinki, Finland Kastrup Sobad sea baths, Copenhagen, Denmark Ciaran Rooney 16731989 LARC 40360 - Review no. 5 - Exhibition 18th May 2020 DETAILS OF THE DESIGN

PIGEON HOUSE PIER SECTION DETAIL

Water sports Instruction Centre Cafe and community space Board launch area Observation Deck Lower deck pontoon platform, at low tide, it sits on sea floor

High Water Mark +4.10 m

Low Water Mark +2.40 m

Recreational Uses and Users of the Site Area Scale 1:250@A0 PIGEON HOUSE PIER PLAN VIEW Pier Bridge Technical Detail

80mm concrete permeable paving slabs

30-50mm bedding layer, graded 6.3-2.0mm grit to BS EN 13242 2002

100-150 mm sub-base

Outlet to soak away/drainage system

Geotextile Sandymount Promenade Plan View membrane High Water Mark +4.10 m

Sub-grade Low Water Mark +2.40 m

Scale 1:50 @A0

Living Breakwater technical drawing

Scale 1:50 @A1 Berm Section Detail

Scale 1:500@A0

FLOOD SIDE PROTECTED SIDE

ECOLOGICAL VALUE - LOW ECOLOGICAL VALUE - HIGH ECOLOGICAL VALUE - HIGH slope 6%

Topsoil

Compacted embankment per Oyster reefs Other type of breakwater material, here are tetrapod units. specification

Clay cap

Breakwater visualisation using Econcrete units Promenade 8 metre cycle lanes -Concrete is precast with pockets to hold marine life Slurry wall - Chemical composition of concrete is modified for marine growth Oysters Oyster worker, inspecting the oysters Oyster reef structure being constructed ECOLOGICAL VALUE - LOW ECOLOGICAL VALUE - HIGH PORES SPACE FILLS WITH SEDIMENT PORES SPACE REMAINS OPEN - Interlocking units create relational strength Ciaran Rooney 16731989 LARC 40360 - Review no. 5 - Exhibition 18th May 2020 NATURAL AND HUMAN INFLUENCES

FLOOD PROTECTION TYPOLOGIES OF SOUTH BULL, DUBLIN BAY SHORELINE ECOLOGY PLANTING Available space for ecology and public use varies

Soil Depth & Quality

Bar-tailed godwit Light bellied Brent Redshank Black guillemot Sanderling Oystercatcher Alnus glutinosa Populus alba Sorbus intermedia Fraxinus excelsior Quercus ilex Pinus nigra maritima Common Tern 0.5m depth 0.5mLAWN depth 1.0m depth 1.0m depth 1.5m depth Zostera noltii SMALL SHRUBS Dwarf Eelgrass 1.5m depth Cockles and LARGE SHRUBS Clams 3-4m depth SMALL TREES

Picea sitchensis Acacia dealbata Arbutus Unedo Eucalyptus gunnii Olea europaea

For plants to survive in coastal zones they must be able to tolerate heat and drought, extreme wind, salt and sand. Not surprisingly given Interaction with edge conditions - natural sandy beach with dunes and the wildlife that lives there the extreme environment they grow in, many seaside plants share a number of similarities. The following species have been selected on Ireland’s marine territory extends far beyond our coastline, it is up 220 million acres (approx. 880,000km2) in size, an area the basis of their tolerance to wind and salt spray, and In exposed coastal areas these are the species which are most likely to succeed. more than 10 times our land mass. There are over 7,300 animal species recorded and 600 species of seaweed in the seas around Ireland (Marine Institute). Ideal Coastal Plants Wind The South Dublin Bay candidate Special Area of Conservation (cSAC) lies south of the River Liff ey and extends from the South Wall to the west pier at Dun Laoghaire. This area has been designated for its extensive sand and mudfl ats, listed Wind is one of the most destructive elements to coastal planting, the relentless as protected Annex 1 habitats in the EU Habitats Directive. These provide important foraging habitat for birds. nature of wind on the coast has a marked impact on the plants. The importance Beneath the sands of Dublin Bay, countless millions of shellfish, worms, crustaceans and other creatures feed on the of careful plant selection at the initial stage, especially when it comes to plankton and detritus washed in from the sea and organic matter brought down by the rivers (Nairn, 2017). Great flocks establishing the all-important primary windbreaks along the front line as they of migratory birds, feed in the area between the tides on Sandymount strand, arriving from as away as Arctic Canada and filter out the worst of winter storms and salt-damaging winds. tropical Africa (NPWs). Marine mammals, including seals, porpoises and dolphins, make parts of Dublin Bay their home. Ammophila arenaria Hebe brachysiphon Rosa rugosa Armeria maritima

DETAIL SECTION - PLANTING ON PIGEON HOUSE PIER

Dune growth is supported by trellis fence, this will help capture sand, creating protection and habitat area for beach wildlife.

Herbaceous planting suitable to Mulching with shingle, flint, grit or gravel will provide exposed coastal conditions sharp drainage while conserving moisture at the roots and aid the cultivation of an even wider range of plants. Topsoil fill depth 500mm Corten steel planter supported by RSJ on concrete foundation Loose pebble mix for drainage Tree rootball to be placed above drainage layer and backfilled with good quality growing medium.

Scale 1:50

SITE IMAGES

Map based on study by J.G. Wilson (1982) There are 5700 animals per square metre that live in Dublin Bay, most are worm types but also include bivalves and crustacea. These are very important to seabirds diet. Interaction with edge conditions -boulder sea defence witn berm - layering the resilience and creating green corridor.

Aerial view of Merrion strand and Dublin mountains The The Green Social Process Process ecological protect SPA’s + SAC’s urban

biodiverse cultural A view towards the northern side of the site. Poolbeg chimney stacks have almost iconic status as symbols of Dublin Merrion strand - the growth development of the spit nature active oyster invest restoration civic recreational learn diverse educational Poolbeg peninsula, - rock armour Sandymount promenade - the cargo Booterstown - Sea defence wall was Irishtown - Beach access has been Half Moon Swimming Club Poolbeg New sea defence revetment steps intervention, this provides social space and allows interaction with the water. Sand dunes on the Poolbeg peninsula impedes access to beach container (left) contains the sandbags erected when the railway line was blocked to prevent flooding pier during the recent good weather for flooding events constructed Ciaran Rooney 16731989 LARC 40360 - Review no. 5 - Exhibition 18th May 2020 PHOTOSHOP PERSPECTIVES VISUALISATIONS

Poolbeg peninsula development - revetment steps Pigeon house pier with water dock and function centre The atmosphere attempts to portray the aftermath of heavy rains and fine weather has arrived, The remnants of water pools on the lower steps, kids in the foreground are jumping in puddles, you can This perpsective is trying to capture the essence of excitement and thrill that most people experience while taking part in fun water and outdoor activities on a summers day. From the onlookers in the also see that the birds, redshanks and brent geese, are sharing the space and nature is encroaching on the steps with sediment and plants colonising. In the middle, people are kayaking in the water, foreground, to the group of people on the roof terrace at the back, the atmosphere is engaging, a place you would like to be. It is an active and a participatory setting with the Dublin mountains in the while other users are simply enjoying the views and space. In the background is the industrial element of the working port environment. background on the left.

Sandymount Promenade, the tiered sunken recreational space also functions as a flood detention pond.

Poolbeg Site - Oyster reef beds

Part of the Oyster Reef intervention, this rendering depicts In the foreground, the cheeky oystercatcher birds picking on the net of oysters while the oyster workers are sorting through the harvest, other workers are mending the nets in the water. In the middle on the left is the living breakwater, in reality this wouldn’t be that close to the oyster reef but I wanted to show the relationship within the water. Dun laoghaire coastline is in the horizon.

Ciaran Rooney 16731989 LARC 40360 - Review no. 5 - Exhibition 18th May 2020