Male Hulhule Bridge Feasibility Report Aug 2011- Final

8/10/2019 Male Hulhule Bridge Feasibility Report Aug 2011- Final

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Ove Arup & Partners Hong Kong LtdLevel 5 Festival Walk

80 Tat Chee Avenue

Kowloon Tong

Kowloon

Hong Kong

www.arup.com

GADL International L

Feasibility Study forof a Bridge betweenHulhumal

Final Report

REP-217093-01

Issue | August 2011

This report takes into account the particular

instructions and requirements of our client.It is not intended for and should not be relied

pon by any third party and no responsibility is

undertaken to any third party.

Job number 217093

d

onstructional and


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GADL International Ltd Feasibility Study for Construction of a Bridge between Mal and HulhumalFinal Report

HULHUMALE BRIDGE FINAL REPORT.DOCX

Contents

Page

Executive Summary i

1 Introduction 1

2 Project Context 2

2.1 Mal 2

2.2 Hulhumal 3

2.3 Ibrahim Nasir International Airport 5

2.4 Greater Mal 6

2.5 The Eye of Maldives 62.6 Funadhoo Island 7

2.7 Moon Bay Marina 7

2.8 Site Conditions 8

2.9 Key Issues 11

2.10 Key Stakeholders 14

3 Alignment Options 15

3.1 Alternatives Considered 15

3.2 Landing Points and Traffic Dispersal 16

3.3 Initial Sifting of Alignment Options 19

4 Airport Operational Issues 21

4.1 Airport Height Restrictions 21

4.2 Ground Transportation 22

4.3 Traffic Volume 24

4.4 Conflicts Between Road and Air Traffic 24

4.5 Airport Emergency Vessels 25

4.6 Conclusions 25

5 Navigation Issues 26

5.1 Marine Activity 26

5.2 Airdraft 29

5.3 Span and Marine Safety 30

5.4 Ship Impact 32

5.5 Conclusions 32

6 Environmental Issues 33

6.1 Introduction 33

6.2 Environmental Legislation, Guidelines, Policies andInternational Conventions 33


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6.3 Baseline Conditions 36

6.4 Potential Impacts and Mitigation Measures 40

6.5 Influence of Climate Change 45

7 Bridge Structure Options 46

7.1 Functional Cross Section 46

7.2 Structural Options (Alignment Option A) 48

7.3 Floating Bridge Option (Alignment C) 52

7.4 Operation & Maintenance 53

7.5 Appearance of the Bridge Options 55

8 Construction Cost Estimates 56

8.1 Methodology 56

8.2 Fixed Bridge on Alignment A 568.3 Floating Bridge on Alignment C 56

8.4 Operation & Maintenance Costs 57

9 Potential Financing & Revenue Models 58

9.1 Alternatives for Financing the Bridge 58

9.2 Sources of Revenue 60

9.3 Tolls 61

9.4 Payment in Kind 62

9.5 Conclusions 63

10 Comparison of Options 64

11 Conclusions & Recommendations for Further Study 65

References

Appendices

Appendix A

Drawings

Appendix B

Artistic Images


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Executive Summary

Introduction

GADL International Limited has commissioned Ove Arup & Partners Hong KongLtd to carry out an initial feasibility study for the construction of a bridge betweenthe Mal and Hulhumal Islands.

This feasibility study was commissioned on the 31stMay 2011. After an initialdesk study, a site visit was carried out from 14thJune to 16thJune 2011. Inaddition to inspection of the site and potential landing points, stakeholderconsultation meetings were carried out. After completion of the site visit, thisreport has been prepared to present the findings of the initial feasibility study.

Alignment Options

Three different alignments have been studied and an initial sifting exercise was

carried out to determine the suitability of each alignment for different bridge types.

Bridge Type Option A Option B Option C

Fixed Bridge Considered furtherUnsuitable groundconditions high risk

High cost and poorfunctionality

Floating Bridge Wave conditions are too rough high risk. Considered further

Alignment A is particularly favourable in terms of traffic dispersal on Mal andshould result in the least amount of congestion on the island. It is also favourablein terms of allowing a direct connection to a future link to Villingili Island as partof the long term goal of connecting the Greater Mal region.

Airport Operational Issues

To maintain safe operation of the airport there are restrictions on the height ofconstruction of the bridge which are very influential to the structural options thatcan be considered for the bridge. In view of the deep water, fast currents andocean swells that are found in the Gaadhoo Koa, one option that could beconsidered would be to construct a bridge from shore to shore without any

intermediate supports in the channel. However, this would require very tall towerswhich would violate the height restrictions.


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In addition to these restrictions it is apparent that the construction of the bridgewill have an influence on the airport landside transport infrastructure system.Although the airport masterplan already considers the scenario of the bridge beingconstructed there may need to be further coordination between the airport

development and government plans for public transport and road infrastructurebetween Mal and Hulhumal.

Navigation Issues

The Maldives is an archipelago and marine traffic is an important aspect ofeveryday life in the islands. Construction of a bridge across the Gaadhoo Koa willhave a significant influence on how vessels navigate around Mal, especially thelarger commercial vessels. However, due to the large number of entries into theatoll it has been confirmed by key stakeholders that there will be no adverseimpact to marine operations if appropriate additional navigation aids are providedfor shipping using alternate channels.

All bridge options will provide sufficient airdraft for resort speedboats, localferries and the airport firefighting vessel to pass under the bridge.

Environmental Issues

Based on the available data it appears that the environmental impacts of the bridgecan be managed and mitigated.

Climate Change Resilience

Hulhumal was built with a formation level 0.5m higher than Mal in order toprovide greater resilience to sea level rise. The bridge, which will promote thedevelopment of Hulhumal, will therefore be of benefit to the climate changeresilience of the nation.

The provision of a fixed link could also assist the nation in coping with someeffects of sea level rise, specifically:

Facilitating disaster relief efforts

Aiding with population mobility in view of shifting land use patterns

Traffic Congestion

There is a concern that the construction of the bridge could increase trafficcongestion on the islands. Ways in which congestion can be tackled could include:

Promoting public transport (buses) on the bridge

Selecting a landing point which provides good traffic dispersal in Mal

Implementing traffic improvements to facilitate dispersal

Restricting types of vehicle that are permitted to use the bridge

Employment in Ferry Sector

Although the construction of the bridge will bring economic benefits to themajority of the population there is a concern that it will cause job losses for thosecurrently either directly or indirectly employed in ferry operations between Mal

and Hulhul/Hulhumal.


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It is possible that bus operations on the bridge could provide appropriatereemployment and this could be promoted by

Retraining schemes (e.g. bus drivers licence, mechanics training etc.)

Trade-in scheme where the government could provide mini-buses in return forferries.

Direct intervention (employment quotas)

Toll structure on the bridge which promotes the use of buses

There would be some costs associated with these schemes but these would be asmall percentage in comparison to the overall project cost.

Bridge Structure Options

Three different options for the bridge structure have been illustrated in generalarrangement drawings and artistic images, two different fixed bridge alternatives

on alignment option A and a floating bridge on alignment option C.


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Construction Cost Estimates

A top down estimate has been made based on historic construction costs of similarprojects calibrated or adjusted for features unique to the project

There are no historic projects of a similar nature in the Maldives. Thereforehistoric construction costs for international projects need to be considered. Theadjustments that need to be made for features unique to this project are:

Construction in the Maldives where all materials need to be imported

Construction in deep water with weak and uncertain ground

Although material costs are relatively high in the Maldives, labour costs arerelatively low compared to the countries where suitable reference projects have

been identified. This has been taken into account in the cost adjustment.

The estimated cost of construction of the bridge is USD 70 to USD 100 million.

Potential Financing & Revenue Models

Based on government policy and current procurement trends in the Maldives it isbelieved that an appropriate PPP structure is likely to be the best way of financingthe project.

The project is unlikely to be financially viable based solely on direct user fees(tolls). Therefore alternative financing and revenue strategies are required. It islikely that a successful strategy will combine the following elements:

Private partner builds the bridge and then maintains and operates it for a fixedconcession period (25 to 30 years)

Initial government capital contribution in the form of Viability Gap Funding

Additional Payment in Kind based on development rights / land leases forcommercial / high value residential property in Hulhumal

Toll revenue collected by the private partner but respecting a pre-agreed tollstructure which promotes public transport on the bridge

It is worth noting that the economic benefits of a project such as this frequentlyexceed the financial revenue that can be generated. This is because there are eitherlong term benefits which are beyond the time frame of a private investor or

because there are benefits which are associated with the project but for which a

direct user charge cannot be applied.In this case, the quality of life benefits achieved by reducing urban congestion inMal and the enhanced climate change resilience by promoting development onslightly higher ground are both significant benefits. Therefore the fact that the

project is not considered financially viable based on direct user fees should not betaken to mean that the project is not worthwhile.

Conclusions & Recommendations for Further Study

All parties consulted were in favour of the construction of a fixed link to connectMal and Hulhumal.

Construction of a bridge is feasible although there exist a number of significanttechnical and financial challenges which must be overcome.


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This Feasibility Study was envisaged as an initial scoping study and was limitedby the time as well as the information available. In view of the anticipatedbenefits of the project it is recommended that a Preliminary Design study iscarried out with the following objectives:

Gather additional data Confirm technical details of the project Assess the impacts of the project Update cost estimates Develop procurement model for the project addressing the financial

requirements

An approximate timeline for the project is given below. It would be possible toslightly reduce the overall procurement timeline for the Design and Build / PPP

procurement route by integrating the scope of works of the Bid ProcessManagement into the Preliminary Design since this would allow prequalificationto start earlier.

In order to control costs at this early stage of project development it could bepossible to subdivide the Preliminary Design into two stages with the aim to limitdesign and investigation costs in Stage 1:

Stage 1 - Conceptual design of options, update of cost estimates and selectionof preferred option

Stage 2 Preliminary design, assessment of impact, further update of costestimates and development of procurement model


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HULHUMALE BRIDGE FINAL REPORT.DOCX Page 1

1

Introduction

The Government of the Republic of Maldives is interested to link various islands

in the Greater Mal region by construction of bridges.GADL International Limited has commissioned Ove Arup & Partners Hong KongLtd to carry out an initial feasibility study for the construction of one such bridge

between the capital Mal and Hulhumal Islands. Hulumal is connected toHulhul (the airport island) by road alongside of the reef.

Mal is the capital and most populous city in the Republic of Maldives. It islocated at the southern edge of North Mal Atoll (Kaafu Atoll).

Ibrahim Nasir International Airport is the only gateway to Maldives and is locatedon the Hulhul Island which is 1km away from the capital, Mal.

A commercial harbour is located on Mal Island and is the heart of all commercialactivities in the country. Mal Island is heavily urbanized, with the built-up areataking up essentially its entire landmass. Almost one third of the nation's

population lives in the capital city, and the current population of this island is over100,000.

Currently the only mode of transportation between Mal and Hulhul islands is byboat / ferry. A link between the two islands by a bridge will make transportbetween the islands easier for both public transportation and cargo movement.

This feasibility study was commissioned on the 31stMay 2011. After an initialdesk study, a site visit was carried out from 14thJune to 16thJune 2011. In

addition to inspection of the site and potential landing points, stakeholderconsultation meetings were carried out with representatives of the followingorganisations:

The Presidents Office Ministry of Housing and Environment Maldives Ports Limited Maldivian Coast Guard Mal Water & Sewerage Company Pvt Ltd Environmental Protection Agency Housing Development Corporation GMR Mal International Airport Pvt. Ltd

After completion of the site visit, this report has been prepared to present thefindings of the initial feasibility study.


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2

Project Context

2.1 Mal

Mal Island is heavily urbanized, with the built-up area taking up essentially its

entire landmass. Slightly less than one third of the nation's population lives in the

capital city, and the population has increased from 20,000 people in 1987 to over

100,000 people today. Mal is the centre of all commerce, administration and

government institutions in the Maldives.

Figure 1 Aerial view of Mal Island (Source: Wikimedia Commons Shahee Ilyas)

Since there is no surrounding countryside, all infrastructure has to be located inthe city itself. Water is provided from desalinated ground water; the water works

pumps brackish water from 50-60m deep wells in the city and desalinates thatusing reverse osmosis. Electric power is generated in the city using dieselgenerators. Sewage is pumped unprocessed into the sea. Solid waste is transportedto nearby islands, where it is used to fill in lagoons.

Figure 2 Progress of land reclamation up to 1992 (Source: [7])


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Reclamation of the lagoon on Mal has added more than half again to the originalland area of the island which now extends almost to the edge of the reef on allsides except for the protruding submarine outer edge of the reef in the south eastcorner of the island.

In February 2002 a reef slope collapse occurred on the north eastern corner of theisland, a solid jetty was destroyed and blocks and debris of the jetty fell down thereef slope. An investigation was made of the engineering geology of the islandwhich concluded that there could be further potential slope failures on the criticalnorth eastern margin of the island.[11]

2.2 Hulhumal

Reclamation of the 188 hectares of Hulhumal began on October 16, 1997 on theHulhul-Farukolhufushi lagoon 1.3 km off the north east coast of Mal. Initialreclamation (or Phase I) consisting of 45% of land mass was carried out by the

Ministry of Construction and Public Works (MCPW) costing USD 11 million.The project was then continued by a Belgian Joint Venture Company,International Port Engineering and Management (IPEM) and DredgingInternational (DI) costing an estimated USD 21 million. All the works involvingreclamation and coastal structure development covered in Phase I was completed

by June 2002.

Development of Hulhumal is masterminded by the government owned HousingDevelopment Corporation (HDC). Originally solely responsible for thedevelopment and management of Hulhumal the corporation is now mandated toundertake government housing projects not only in Hulhumal but elsewhere inthe Maldives as well. Its mission now is to relieve the urban congestion in the

Maldives by providing housing in a socially responsible and commercially viablemanner.

HDCs main focus currently remains in developing Hulhumal into a uniqueisland city in the North Mal Atoll, while creating opportunities for better homes,health, employment and education services in the Maldives. HDC has three rolesin the development of Hulhumal.

Firstly, it acts as a master developer, delivering the vision, inspiration andimagination of the project in a manner that is feasible and commercially viable.

Secondly, HDC is a builder, investing in the infrastructure necessary for

quality living and business prosperity. These include the development of roads,landscaping, and ensuring that basic utilities as well as other essential servicesare available for investors and residents.

Lastly, HDC acts as regulator, overseeing detailed planning, architecturalguidelines and building regulations.

HDC deals with the lease and sale of land as well as developed property onHulhumal. The company focuses on three broad areas of real estate development:residential, commercial, and industrial.

Primary developments in terms of the required physical and social infrastructureand residential developments were completed in 2004 and the very first settlement

of Hulhumal began in the middle of 2004 with a resident population of just over1000 people. The current population is approximately 20,000 people.


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The target completion date for the development is 2020 with a target populationof 60,000. At that time the population density would be approximately half thecurrent density of Mal Island.

Figure 3 Hulhumal Master Plan (Source: HDC)

Development so far has primarily been residential in the north east corner ofHulhumal including social housing. It is understood that some social housingleases are being sublet to residents from outlying islands thereby frustrating theaim of tackling growing urban congestion in Mal.

Construction of a bridge between Mal and Hulhumal would be very beneficialto the further development of Hulhumal and to achieving the objective offostering balanced land use and a diverse range of developments. Commercial

developers would potentially be more likely to invest if Mal was seen to be moredirectly within their catchment of potential customers. Mal residents might also

be more likely to move to Hulhumal if they could more easily commute to theircurrent employment on Mal thus achieving the aim of reducing urban congestion.

Figure 4 Beachfront residential developments in Hulhumal

Figure 5 Streetscape in Hulhumal


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Hulhumal clearly has great potential to improve the quality of life for the

population by providing a lower density of urban living in a well planned

development which effectively utilizes the land to maximize environmental and

economic efficiency in terms of living space, productivity and provision of

employment. However, it is currently underutilized and it may require betterconnectivity to help it to fully realize that potential.

2.3 Ibrahim Nasir International Airport

Ibrahim Nasir InternationalAirport (MLE) is the maininternational airport in theMaldives. Despite the upgradingof Gan and HanimaadhooAirports to internationalstandards, Ibrahim NasirInternational Airport is likely toremain the main gateway intothe Maldives for tourists.

Figure 6 Approach to Runway 36 (Source: Wikimedia Commons PalawanOz)

The airport completely dominates Hulhul Island and has been constructed onreclamation in the lagoon of the island. The airport opened to the public inApril 1966 and has been through a series of renovations and upgrades includingseveral additional stages of reclamation to expand the land area of the airport.

Figure 6 shows the situation in 2003 before more recent reclamation at thesouthern end of the island.

The Maldives Airports Company Ltd. (MACL) was formed in 1994 as afinancially and administratively independent corporate entity to manage theairport. MACL is governed by a Board of Directors appointed by the President ofthe Maldives

On 15 July 2010, the airport was privatised and on 25thNovember 2010, MACLofficially handed over the aerodrome license of the airport to the newly formedGMR Mal International Airport Pvt. Ltd, a consortium between GMR Group andMalaysia Airports. The airport has been leased to the consortium for 25 years with

the aim to develop MLE into a global standard airport by the year 2014. MACL

Tourism accounts for 28% ofMaldivian GDP and more than 60%of foreign exchange receipts.


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will continue to be responsible for some airport functions including Air TrafficControl and Aviation Security Command.

The centrepiece of the development plans is a new International PassengerTerminal to be built on a reclaimed lagoon to the east of the runway. Other

developments include extension of the runway to the north to establish a RunwayEnd Safety Area (RESA) at the south end of the runway.

2.4 Greater Mal

Although the objective of this assignment is to study the feasibility of a bridgebetween Mal and Hulhumal (via Hulhul), we are aware that this is part of alarger long term desire to link together a series of islands in the Greater Malregion.

Figure 7 Greater Mal

As far as the current assignment goes, the main way in which we have consideredthis long term goal is in terms of the traffic connectivity. The physical geographyof Greater Mal as well as the current road layout in Hulhul and Mal lends itselfto the eventual fixed link being a backbone running along the perimeter of the

atoll as indicated in Figure 7.

2.5 The Eye of Maldives

One of the islands in the Greater Mal region is Gulhi Falhu which is currentlybeing developed into the Eye of Maldives.

Global Projects Development Company (Pvt) Ltd has a concession agreementwith the Government of the Republic of Maldives to reclaim and develop GulhiFalhu lagoon. Reclamation of Phase I (10 hectares) was completed on 18September 2010. Phase II (40 hectares) will commence in 2011.

The Eye of Maldives masterplan currently shows a fixed link between GulhiFalhu and Villingili islands as indicated in Figure 8.


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Figure 8 Eye of Maldives (Source: Global Projects Development Company Pvt Ltd)

2.6 Funadhoo Island

Funadhoo Island is a fuel storage facility operated by the government and locatedbetween Mal and Hulhul islands.

It is understood from discussions with the Technical Advisor to the Minister ofHousing and Environment that this facility will be relocated. We have thereforeassumed that it would be possible for the road to pass over this island and indeedthere could be some benefit to linking to this island to facilitate redevelopmentsince it is close to Mal.

Figure 9 Funadhoo Island (Source: Google)

The island includes an area of shallow water to the south east where breakingwaves are observed.

2.7 Moon Bay Marina

We are aware of the Moon Bay Marina project from the promotional video whichwas widely circulated on the internet in early 2009. If this project were to goahead it would have a significant impact on planning of the bridge. However, it isour understanding that this project will not be progressed and we have thereforeexcluded it from our consideration in preparing this report.


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2.8 Site Conditions

2.8.1 Topography

The islands are flat and are typically around 1.5m to 2.0m above mean sea level.

2.8.2

Bathymetry

Bathymetric data has been obtained from four sources:

Admiralty Chart [1]

University of South Florida (USF) bathymetry survey [12]

Extract from recent Indian Survey data provided by Maldivian Coast Guard

Extracts from bathymetric survey of Hulhul Island [4]

There are some contradictions in the bathymetric data but it is clear that the waterdepth in the channel exceeds 50m and that the reef slopes are generally relativelysteep. The data also appears to consistently indicate that the water is slightlyshallower in the southern part of the channel and that the reef slope of the southeast tip of Mal Island is somewhat gentler.

The USF data is the most detailed and the most recent so we have based our studyon this. For the further development of the project it would be necessary tovalidate the USF data and obtain a digitised version.

Figure 10 Extract from USF bathymetry data [12]


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2.8.3 Metocean conditions

Metocean conditions are expected to be characterised by a moderate tidal range,

strong currents, moderate to rough ocean swells and steady winds. The conditions

are affected by the monsoons. Each year there are two monsoons seasons, the

north-east monsoon, (Iruvai) from December to April and the south west monsoon,

(Hulhangu) from May to October.

Tide

Tidal levels have been determined from the Admiralty Chart [1]. The tidal rangeat Mal and nearby is about 0.7m at Spring tides and 0.3m for Neap tides. A meansea level of +0.6mCD has been assumed for this current study.

Place Heights in metres above datum (mCD)

MHHW MLHW MHLW MLLW

Mal 0.9 0.8 0.5 0.3

Current

The Maldives are affected by both seasonal and tidal currents. [1] states that theGaadhoo Koa channel is affected by seasonal monsoons causing strong currentsup to 6 knots across the mouth of the channel. Tidal currents occur due to thediurnal filling and emptying of the lagoons through the limited passages in the

barrier reef. The Maldivian Coast Guard informed us that the tidal current strengthin the Gaadhoo Koa has increased due to the reclamations in the area.

Waves

The wave height varies seasonally with the monsoons and June to August duringthe south west monsoon has the most potential for large swells. During this periodthe predominant wave direction is from the south. Seas are generally moderate(around 2m wave height) but can be rough (2.5m to 4m wave height) at times.

During the site visit strong breaking waves were observed on the shorelinesexposed to the ocean, specifically the east coast of Mal and the southern

breakwater of Hulhul Island where minor overtopping was also observed. It wasnoted that the wave strength tended to reduce inside the atoll but surf was alsoobserved at Funadhoo Island despite being some way from the edge of the atoll.

Wind

Steady winds exist at the site with the average monthly wind speed being between4m/s and 6m/s and with calms never exceeding more than 2% of a month. The

prevailing winds which can become quite strong, are from the SW-W-WN duringthe south-west monsoon and N-NE-E during the north-east monsoon. In May to


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October wind gusts may reach between 35-45 knots. However, the Maldives arenot prone to tropical cyclones as it is outside of the cyclone region.

2.8.4

Ground conditions

Archipelago geology

The Maldives Archipelago comprises two chains of coral reef islands locatedabove the north-south trending submarine Laccadive-Maldives Ridge. The

basement of this ridge formed millions of years ago as the result of hot-spotrelated volcanic activity, with subsequent subsidence and carbonate sedimentationresulting in a thick overlying limestone sequence. The islands themselves, whichonly began to form around 5,500 years ago, are composed of reef-derivedcarbonate sediment deposited by waves and currents along the rims of coral reefatolls, giving rise to sub-circular clusters of islands, each surrounding a lagoon.The geomorphology of the islands is constantly changing through action of wind

and sea which leads to erosion and deposition of banks, beaches and cays.

Due to their mode of deposition and post-depositional processes, carbonatedeposits, and particularly those associated with coral atolls typically exhibithighly variable characteristics, including zones of unconsolidated or poorlyconsolidated granular deposits, zones of cementation, coral cavities anddissolution voids.

Local geology

After collapse of a section of the north eastern reef slope of Mal in 2002, a studywas made to characterize the engineering geology environment of the margins of

Mal Island, especially the north-eastern slope where the documented upper slopefailure occurred. The Phase 1 Assessment Report [11] has been made available tous.

Based on interpretation of a high resolution multi-beam bathymetry survey thereport makes a number of conclusions which are of particular significance to the

bridge feasibility:

Several surfaces of rupture (head scarps) are observed corresponding tocollapse along the north eastern section of Mal Island

Blocks and debris are observed down slope of the collapses

The sea floor between Mal and Hulhul Islands shows karst like figures(sinkholes) on the underwater plateau. The sink holes form lineaments whichare parallel to the general orientation of the NE shores of Mal Island.

Expected conditions

It is expected that the sea floor will comprise of carbonate deposits overlain inplaces by unconsolidated granular deposits (coral sand). Sink holes are expectedin some locations.

Due to the high tidal currents in the channel it is anticipated that sand depositswill tend to accumulate in deeper areas such as the sinkholes and will not be

present in shallower areas. This has been anecdotally confirmed during our

discussions with the Maldivian Coast Guard who have made a number of dives tothe sea floor and were able to describe the conditions.


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2.9 Key Issu

A number of key issues

2.9.1

Project Fi

There are clearly signifiproject and there is greathe bridge be built. Howexpenditure and securin

project going ahead.

2.9.2

Cost & Pr

Intimately related to pro

initial capital requiremewhilst at the same time

In this particular case anconstruction in the remologistics of importationand prefabrication can b

2.9.3 Deep Wat

The Gaadhoo Koa chanshore to shore. Strong c

represents a challengingdefine the metocean con

&

Feasibility Study for Construction of a Bridge betw

es

for the project have been identified:

nancing

ant economic benefits that would be obtaineinterest from the Government and stakehol

ever, the project would represent a significathe financing of that initial investment is cr

acticality of Construction

ect financing is the need to reduce costs to t

ts. This requires the bridge to be designed echieving the project objectives.

economic design needs to respect the practi te location of the Maldives. This means cons

f materials and planning the extent to whichenefit the project.

er

el is up to 60m deep and it is a thousand merrents and ocean swells are present in the ch

environment for construction and more dataditions in the channel.

en Mal and HulhumalFinal Report

Page 11

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&


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2.9.4 Weak and Uncertain Ground Conditions

There is no ground investigation data available for the site. However, the localgeological conditions indicate the ground is likely to be weak and highly variablecarbonate deposits. Suspected sinkholes have already been identified in some

parts of the sea floor. There will be considerable technical challenges indeveloping appropriate foundation solutions and reliable geotechnical data isrequired.

A secondary consideration with respect to the weak ground conditions is that astudy will need to be made to ensure that the construction of the bridge does notadversely affect coastal processes and lead to acceleration of the erosion of thenorth eastern corner of Mal Island.

2.9.5

Airport Height Restrictions

Construction of the bridge adjacent to the airport imposes stringent restrictions onthe height of structure that can be built.

Considering the deep water it would be desirable to have long spans but the heightrestrictions places limits on the types of bridges and maximum spans that areachievable.

The span limitations become particularly significant in the reef slope areas whereit is highly undesirable to locate a foundation. This means that the bridge mustspan across the slope areas.

2.9.6 Navigation

The bridge needs to have a relatively low profile due to the airport heightrestrictions. This will inevitably prevent large ocean going vessels from passingunder the bridge. Therefore the largest vessels which must be able to continue tosafely use the Gaadhoo Koa after construction of the bridge need to be identifiedto determine the navigation requirements. Larger vessels will need to use alternate

passages into the atoll and stakeholder consultation on this issue has been carriedout due to its importance.

2.9.7

Operation & Maintenance

The bridge will represent a large capital investment and it must therefore beoperated and maintained to provide a high quality service level throughout a longservice life. In the Maldives there are few, if any, bridges and therefore theinstitutions to operate and maintain the bridge do not exist.

Implementation of the project must therefore either include creation and capacitybuilding of a dedicated institution or else turn over the operation to the privatesector to attract experienced international organisations.

The design of the bridge should also seek to minimise the operation andmaintenance burden.


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2.9.8 Traffic Congestion

There is a concern that the construction of the bridge could increase trafficcongestion on the islands. This is an issue that needs to be addressed with a trafficimpact assessment. Ways in which congestion can be tackled could include:

Promoting public transport (buses) on the bridge

Selecting a landing point which provides good traffic dispersal in Mal

Implementing traffic improvements to facilitate dispersal

Restricting types of vehicle that are permitted to use the bridge this couldmean private vehicles registered in specific areas or introducing a taxi zoningscheme to control numbers of taxis permitted to operate in specific areas

2.9.9

Impact on employment in ferry sector

Although the construction of the bridge will bring economic benefits to themajority of the population there is a concern that it will cause job losses for thosecurrently either directly or indirectly employed in ferry operations.

At present, the Mal-Hulhumal ferry service is operated by the MaldivesTransport and Contracting Company (MTCC), a majority state owned enterprisewhich operates a number of ferry routes as well as providing other transport,logistics and construction services. There are 18 return trips per day and the

journey takes approximately 20 minutes. The service is operated in a relativelyefficient manner and prices appear to be based on cost plus profit. [6]

On the other hand, the Mal-Hulhul service is provided by a number of

individual operators working as an association or cartelized union as opposed to acompany. The fare charged is relatively expensive compared to MTCC fares butthere appear to be deliberate inefficiencies in the operation due to there beingsignificantly more ferries operating than are actually required meaning that eachvessel is only utilised for approximately 20% of the day. [6]

It is worth noting that thereduction in demand for ferriesto Hulhumal may be offset byincreasing demand for ferryoperations between Mal and the

Eye of Maldives developmentmeaning that some ferries couldsimply shift the route on whichthey operate. However, therecould still be a net reduction indemand for ferry services and to avoid negative social impacts it is suggested thatthe government could implement reemployment schemes for affected persons.

It is possible that bus operations on the bridge could provide appropriatereemployment and this could be promoted by

Retraining schemes (e.g. bus drivers licence, mechanics training etc.)

Trade-in scheme whereby the government could provide mini-buses in returnfor ferries.

Bus operations on the bridge providean opportunity for reemployment as

well as promoting public transport


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Direct intervention (employment quotas)

Toll structure on the bridge which promotes the use of buses

There would be some costs associated with these schemes but these would be a

small percentage in comparison to the overall project cost.Since October 2010, MTCC has operated the Hulhul to Hulhumal bus serviceand there is clearly the possibility for their bus operations to expand tocompensate for the loss of the Mal to Hulhumal ferry service.

A decision will need to be taken on whether bus operations are to be carried outby a single franchised company or whether registered individuals operating non-scheduled services could also be permitted to operate buses. In Hong Kong, bothsystems are run in parallel (Figure 11) for the public light buses and a dual systemcould also be considered in the Maldives. This could provide greater opportunityfor individual Mal-Hulhul ferry operators to participate in the bus sector.

Figure 11 In Hong Kong, green minibuses operate a scheduled service, with fixed routesand fixed fares whereas red minibuses run a non-scheduled service according to market

demand, although many routes may in effect become fixed over time.

2.9.10 Environmental impact

The bridge will be constructed over coral in a marine environment which means acareful assessment of the potential environmental impacts will be required and anenvironmental management plan will need to be developed.

2.10 Key Stakeholders

In developing a project of this nature, stakeholder consultation is important to

ensure that views of interested parties are taken into account. During the course ofthis feasibility study a number of key project stakeholders have been identified:

Government of Republic of Maldives Maldives Airport Company Ltd

GMIAL Housing Development Corporation

Environmental Protection Agency

Maldives Ports Limited

Maldivian Coast Guard Maldives Transport and Contracting Co.

Mal to Hulhul Ferry Operators STELCO

Maldives Water & Sewage Co.

Residents of Mal and Hulhumal

Preliminary consultation was carried out with some stakeholders during the sitevisit and this report takes account of the views expressed. Further consultation

will need to be carried out during later project stages.


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3

Alignment Options

3.1 Alternatives Considered

Ibrahim Nasir International Airport stands between Hulhumal and Mal and any

road linking the two must pass either to the north or to the south of the runway.

Figure 12 Satellite image of Mal and Hulhumal

The Hulhumal to Hulhul Link Road already connects to the southern end of the

runway and it is natural to consider extending this across the Gaadhoo Koa

channel to reach Mal, particularly since this road will also provide access to the

new International Passenger Terminal which is currently under development.

Alignment options passing to the north of the runway were briefly considered but

were discounted due to the significant additional cost and environmental impact

which would be associated with such a circuitous route. Therefore, all alignment

options considered pass to the south of the runway.

Three alignment options have been developed which are: Option A which crosses the channel in a northeast-southwest direction and

connects the southern tip of Hulhul Island to the shallow water to thesoutheast of Mal. The alignment follows a gentle curve in order to stay clearof the sinkhole features observed further north in the channel and makeslandfall close to the Tsunami Memorial.

Option B which is the most direct route across the channel and has theshortest shore to shore distance although it crosses the sinkhole area describedin Section 2.8.4. This option is aligned in an east-west direction and thelanding point on Mal is the vacant land to the north of the beaches

Option C which makes use of Funadhoo Island to separate the crossing intotwo parts albeit following a somewhat indirect route.


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These alignment options are illustrated in Drawings 217093/001 and 002 whichare provided in Appendix A.

3.2 Landing Points and Traffic Dispersal

3.2.1

Option A

Alignment Option A makes use of the open area to the east of the junctionbetween Ameene Magu and Marine Drive.

At this location the streets are relatively wide and offer excellent dispersal into theexisting Mal road network. Space is available for construction of the bridgeabutments although it is likely that the helipad may have to be relocated in orderto provide sufficient space for tolling facilities.

This landfall also gives the best opportunity for future connectivity to Villingili,

either via Ameene Magu or along the southern section of Marine Drive.

On Hulhul Island this option provides excellent connectivity as the road wouldbe a direct extension of the Hulhumal to Hulhul Link Road. A spur to theairport facilities west of the runway would of course be retained.

Figure 13 Landing Point A on Mal Island

Figure 14 Marine Drive


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Figure 15 General view of landing point (left) and Ameene Magu (right)

3.2.2

Option B

Alignment Option B would make use of the open land to the south of theSTELCO substation on Mal Island which provides sufficient space for the bridgeabutments, connection to the local road network and toll plaza. The ownership ofthis land was not established but it is not currently being used.

Figure 16 Landing Point B on Mal Island

The main disadvantage with this landing point is that Bodhuthakurufaanu Magu isquite narrow at this location meaning traffic dispersal would be difficult.

Figure 17 Bodhuthakurufaanu Magu


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Figure 18 Narrow one-way side street (location A in Figure 16)

On Hulhul Island the traffic connection is the same as Option A.

3.2.3

Option C

The purpose of Option C is to make use of Funadhoo island and to split thecrossing into two smaller stretches.

The landing point on Mal would be at or near Fishermans Park on the north sideof the island.

Limited land is available at this location and it is likely that reclamation of someof the harbour area would be required if toll facilities were to be located on MalIsland. Alternatively the toll facilities could be at the Hulhul end of the bridgealthough this would still require some reclamation.

The landing point is located close to the commercial centre of Mal and

Bodhuthakurufaanu Magu is narrow at this location. Traffic dispersal would bedifficult and would probably require road improvements and one-way systems.

Figure 19 Landing Point C on Mal Island


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Figure 20 Commercial buildings at Landing Point C

Although access is provided to Funadhoo the primary purpose of the link is for

travel between Mal and Hulhumal and the overall travel time will be increasedby the indirect route.

3.3 Initial Sifting of Alignment Options

3.3.1 Floating Bridge Option

Two fundamentally different types of bridges will be considered in this report:

Traditional fixed bridge with foundations on the sea floor

Floating bridgeThe feasibility of a floating bridge is very dependent upon the wave and currentconditions. At the southern end of the Gaadhoo Koa channel rough waveconditions are expected which will exceed design values of previously constructedfloating bridges. Even if a design solution could be arrived at it would lead to arelatively high risk solution which is not preferred. Therefore the floating bridgeis only considered on Alignment Option C which is set back from the edge of theatoll and where the wave strengths will be significantly lower. There is alsoexpect to be a reduction in current strength at this location.

3.3.2

Exclusion of Alignment Option B

It is possible to exclude Alignment Option B from further consideration at thisearly stage due to the unsuitable ground conditions. The alignment crosses an areaof extensive karst features (sinkholes) which would make selection of suitablelocations for the bridge foundations difficult if not impossible. Furthermore, thewest abutment of the bridge would be located on the steep margin of Mal Islandwhich is vulnerable to slope collapse.

Alignment Option A crosses the channel further to the south away from theobserved areas of sinkholes and the landfall on Mal Island is the south eastern

point where slope failures have not been observed. The engineering feasibility ofbridge construction on this alignment is much more favourable.


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In terms of traffic, alignment Option Ais also more favourable than Option Bsince it can connect directly to wide southern section of Marine Drive providingdispersal through Majeedi Magu or Ameene Magu. This option will also facilitatefuture connectivity to Villingili Island.

The disadvantage of Option A is that it will have a significant impact on the waveformation at Surfers Beach which is likely to be detrimental to the quality ofsurfing. This impact is partly mitigated by the bridge giving easier access to the

beaches on Hulhumal.

Despite this undesirable impact on leisure resources, Option A must be consideredpreferable to Option B since the latter is unlikely to be feasible as explained above.Option B is therefore excluded from further consideration.

3.3.3 Fixed Bridge on Alignment Option C

If it were highly desirable to include a link to Funadhoo as part of this study thenthe construction of a fixed bridge on Alignment C could be achievable. However,we have not considered this option because:

The overall length of the bridge would be greater on Alignment C (and thewater depth is greater) so the cost would be higher

The travel time would be greater between Mal and Hulhumal thus theeffectiveness of the bridge in achieving its primary function would be reduced

Traffic dispersal on Mal is less favourable for Alignment C

The reef geology is less stable at the Alignment C landing point

For these reasons, we have only considered a floating bridge on Alignment C.

3.3.4

Summary of Initial Sifting Exercise

The initial sifting exercise is summarised in the table below which shows whichoptions are considered further and why:

Bridge Type Alignment A Alignment B Alignment C

Fixed Bridge Considered furtherUnsuitable groundconditions high risk

High cost and poorfunctionality

Floating Bridge Wave conditions are too rough high risk. Considered further


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4

Airport Operational Issues

4.1 Airport Height Restrictions

The most significant operational issue associated with the airport is the heightrestrictions that must apply.

The airspace around airports is to be maintained free from obstacles so as topermit aircraft operations at the airport to be conducted safely and to prevent theairport from becoming unusable by the growth of obstacles around the airport.This is achieved by establishing a series of Obstacle Limitation Surfaces (OLS)that define the limits to which objects may project into the airspace.

As a bridge would be located on the south west side of the airport island, we haveestablished the OLS for Runway 36 (south part of the runway) and have definedthe height limits for objects in this area.

Over the next years the airport will undergo major modifications with theobjective to improve safety and security standards at the airport. From the MalInternational Airport Draft Master Plan [1] we have gathered the following detailsregarding the implications for Runway 36:

Provision of a minimum 90 metre Runway End Safety Area (RESA) forRunway 36;

Installation of a blast fence, with frangible mounting to protect vehicles on theperimeter road.

The Draft Master Plan states that the blast fence will be of 3.8 metres height and

60 metres length and will provide protection for vehicles, including cateringtrucks, from take-off thrust jet blast from four-engine aircraft such as the B747-400. A more recent CAD plan obtained from the Client shows the blast fence nowextended to 220m length but it is assumed the height is not significantly changed.

We have established the OLS based on International Civil Aviation Organization(ICAO) standards and have used the following assumptions:

Runway Code Number 4, Instrument Runway

Take-off climb surface of Runway 36 located 190 m north of blast fence

Location of threshold 36 will remain unchanged

No clearway provided at Runway 36

We have set up the OLS based on these assumptions and have identified thefollowing surfaces as critical for the elevation of infrastructure, like the bridge,road connections or other installations in the south or south west of Runway 36:

a) Inner Horizontal: 45m height

b) Transitional: 14.3% slope

c) Take-Off Climb: 2.0% slope

d) Approach: 2.0% slope


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The established OLS can be seen in Figure 21 below. Each contour shows anelevation increase of 5 metres. The height of the lowest contour equals the heightof the relevant OLS reference point (0) which is the runway elevation. This has

been taken as 2m above mean sea level.

Figure 21 Critical OLS (Source: Arup)

These surfaces have been plotted on Drawings 217093/001 and 002 and have beenused in the development of the bridge options. It is important to note that theseOLS were established by Arup for the purpose of this study. In case more detailedstudies are carried out, the OLS and runway elevation should be confirmed by theairport authorities.

The modifications to the runway ends address two major safety issues, theintroduction of a RESA and the installation of a blast fence. With lengthening therunway by 140 metres to the north to maintain the Take-Off Run Available(TORA), the Take-Off Climb surface for Runway 36 is moved north which

provides sufficient height for installing a 3.8 metre blast fence. The road south ofthe blast fence must be restricted to vehicles of less than approximately fourmetres height.

We have observed that vehicles operating on the road to the west of the runwayresult in a transient obstacle in the Transitional OLS and this is understood to bean acceptable minor non-compliance. However, for the purpose of establishing thealignment of the bridge we have aimed for a minimum clearance of 4.0 metres

between the road level and both the Take-Off Climb and the Approach OLS. Thiswill allow vehicles to operate on the road without becoming an obstacle. Thesesurfaces are considered more critical to aircraft safety than the Transitional OLS.

4.2 Ground Transportation

The construction of a bridge will change the quantity and quality of traffic

between the Mal and Hulhul islands.

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The largest segment of passengers at MLE are international tourists of whichapproximately 45% transfer to domestic air services. The majority of theremainder transfer to resort hotels by speedboat. Only a limited number of touristsvisit Mal Island.

At present both the resort speedboats and the Mal-Hulhul ferry services operatefrom the harbour area to the west of Hulhul Island. However, with constructionof the new International Passenger Terminal to the east of the runway the resortspeedboats will operate from within the seaplane lagoon meaning that the westernharbour area will be solely for the ferry services and airport operations.

Figure 22 Harbour facilities after construction of new International Passenger Terminal

Currently, the speedboat and ferry terminals are the main interchange stationbetween air and ground level transport. With construction of the bridge therewould be continued demand for harbour areas to facilitate transfer to the resortspeedboats but there will also be demand for an interchange station next to the

passenger terminal which connects various road traffic transportation modes. Theinterchange station could host pick up, drop off and short term parking facilitiesfor the following modes of transportation:

taxi

limousines hotel and tour operator buses scheduled buses

The current airport masterplan allows for the case where the bridge is constructedby providing a surface parking area to the north of the passenger terminal buildingto cater for anticipated demand. It is possible that this could eventually be furtherdeveloped into an interchange station with the loss of area for at grade parking

being compensated with the construction of a multi story car park.

After construction of the bridge the cargo quay and Mal Island ferry may nolonger be required. However, there will be a need for road cargo unloading and

bus depot facilities. It is possible that these could be located in the areas vacatedby the sea based ferry and cargo operations.


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4.3 Traffic Volume

We are not aware of any studies that have been carried out that estimate the futuresea and road traffic volume.

The road to the south of the airport is currently used for public transportationbetween the airport and the development of Hulhumal and also used as airportservice road between the airport functions to the west and the east of the runway.The road has sufficient width for 2 lane traffic (approx 7.5m).

The traffic on this road is likely to increase significantly after construction of thebridge. There will be three components to the traffic:

Traffic between Mal and Hulhumal

Traffic between Mal and the main airport facilities to the east of the runway

Traffic between the airport facilities to the east and west of the runway

It can be surmised that the most heavily trafficked portion of the Mal toHulhumal road will be the section between the bridge and the InternationalPassenger Terminal and that any traffic studies to be carried out will need toconsider the airport landside transport infrastructure system as well as the traffic

between Mal and Hulhumal. It is possible that this section of road should bewidened to a dual two lane carriageway.

4.4 Conflicts Between Road and Air Traffic

The airport improvements plan to solve the conflicts between road and air trafficat the Runway 36 southern threshold as required by the concession. However, theroad traffic on the Hulhumal to Hulhul Link Road in the north east of the future

passenger terminal building is not entirely independent from take-off and landingactivities from the sea plane runways. On a particular zone of the road signage iscurrently provided instructing road traffic to give way for sea planes.

As the traffic volume will increase and the type of traffic will change with theintroduction of a bridge, this conflict will become more severe and the currentsolution may not be acceptable.

The optimum solution for road traffic would be to relocate the runways but this islikely to be either very expensive or highly disruptive to airport operations. Analternative concept could be to close the road during take-offs or landings using

traffic signals and a barrier as is currently adopted at Runway 36 (refer Figure 23).Since not all sea plane movements cause conflict with the road this solution willalso allow air traffic control authorities to determine when traffic should bestopped. At present individual drivers use their judgement as to whether the flight

path requires them to give way.


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Figure 23 Signalised traffic control at Runway 36 this solution could be adopted on theHulhumal-Hulhul Link Road to deal with conflicts between road traffic and sea planes

Whether this solution is feasible will depend on the future road and sea planetraffic volume. Also critical will be to develop a reliable technical solutiontogether with operational procedures that will be accepted by the authorities.

4.5 Airport Emergency Vessels

The airport operates a number of emergency vessels. These are discussed inSection 5.2.1 with respect to the need to ensure these vessels can navigate underthe bridge.

4.6 Conclusions

The airport height restrictions are very influential to the structural options that canbe considered for the bridge. In view of the deep water, fast currents and oceanswells that are found in the Gaadhoo Koa, one option that could be consideredwould be to construct a bridge from shore to shore without any intermediatesupports in the channel. However, this would require very tall towers whichwould violate the height restrictions.

Super long span structures

Stonecutters Bridge, with a span of 1,018mcould cross the Gaadhoo Koa channelwithout any foundations in the water.

However the tower is 300m tall making thiskind of long span bridge completelyunsuitable for construction adjacent to theairport runway.

In addition to these restrictions it is apparent that the construction of the bridgewill have an influence on the airport landside transport infrastructure system. Thishas already been considered within the airport masterplan which considers thescenario of the case of the bridge being constructed. However, as the planning ofthe bridge progresses there may need to be further coordination between the

airport development and the government plans for public transport and roadinfrastructure between Mal and Hulhumal.


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5

Navigation Issues

5.1 Marine Activity

A wide variety of vessels are found in and around the North Mal Atoll includinglarge ocean going vessels as well as small powerboats, ferries and dhonis.

Container ship (MV Seaboxer) Cruise ship (Nautica)

72 sailing yacht 140 motor yacht

Figure 24 Examples of large vessels (airdraft greater than 20m)

50 motor yacht Live aboard dive vessel

Luxury tourist dhoni Maldivian Coast Guard CGS Huravee

Figure 25 Examples of medium sized vessels (airdraft between 5m and 20m)


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Local ferry Typical speedboat

Fishermans dhoni Maldivian Coast Guard patrol craft

Figure 26 Examples of small vessels (airdraft less than 5m)

The main berthing areas in Mal include facilities for the airport ferry, thecommercial harbour as well as the marina and ferry berth to the south of the island.There is a commercial anchorage inside the atoll to the north west of Mal Island.

Figure 27 Berthing areas on Mal

In the commercial harbour operated by Maldives Ports Limited, large cargo

vessels are handled at the alongside berth (Magathu Faalan) as well as atanchorages offshore using barges. Most of the container ships are handled at the


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alongside berth. The port handles all types of cargo except dry bulk, liquefiedpetroleum and gases. The airport ferry mainly serves passengers travelling to andfrom Ibrahim Nasir International Airport.

Figure 28 Passages currently used to enter the atoll

Referring to Figure 28, the Gaadhoo Koa is the passage between the reefs fringingMal and Hulhul which is about 740 m wide at its outer end and has a depth of35m in the fairway. At its inner end the passage divides, passing each side ofFunadhoo with deep water in both channels. The Gaadhoo Koa is therecommended approach to the anchorage area north of Mal for all vessels at safespeed.

The northern entrance to the atoll is through Bodukalhi (Kanduoiygiri Passage).

Mal Villingili passage is another safe passage for safe entrance to Mal


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anchorage. but mariners should exercise caution when using this channel as ashoal of 5.0m lies in the centre of the channel. [9]

5.2 Airdraft

5.2.1

Airport emergency vessels

As shown in Figure 22, the airport has a dock for marine rescue / firefightingvessels. These would need to be rapidly deployed in the event of any incidentwhich involved an aircraft either overrunning or landing short of the runway. It iscritical that the bridge provides sufficient airdraft for these vessels.

The firefighting vessel has an airdraft of approximately 7m and this is theminimum requirement for the bridge. This requires that the minimum soffit levelof the bridge shall be:

MHHW +0.9mCD

Vessel Height 7.0m

Safety Margin 1.5m

Minimum Soffit Level 9.4mCD

5.2.2

Controlling factors

A number of controlling factors limit the airdraft that will be available under thebridge:

Airport height restrictions Maximum gradient of road Minimum structural depth Safety margin

These factors are illustrated diagrammatically below:

Figure 29 Limiting factors controlling airdraft

The approach surface to the airport runway means the road has to be at arelatively low elevation on the shore of Hulhul Island.

The road can climb towards the centre of the channel but the gradient has amaximum value which limits the elevation of the road at the navigationchannel.

The bridge itself has a structural depth which has a minimum value whichmeans that the underside of the bridge is at a lower elevation than the road.

Finally, it is normal to establish a safety margin to allow for pitch and heave

of the vessel as well as human error.


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In combination these factors mean that the maximum vessel airdraft that can beprovided under the bridge is approximately eight to twelve metres.

This means that after construction of the bridge large vessels would not be able tonavigate through the channel but smaller vessels including the airport firefighting

vessel would be able to including the airport emergency vessels.

5.2.3

Impact of limited airdraft

Construction of a bridge across the Gaadhoo Koa will inevitably restrict theshipping that is able to use the channel. However, both Maldives Ports Ltd and theMaldivian Coast Guard were consulted on this issue and neither stakeholderraised any concern over the airdraft being limited to around 8m. It was noted thatthere are several alternative channels into the atoll and that in the future it isintended to shift the commercial harbour to Gulhi Falhu in any case.

Therefore, the impact of limiting the airdraft through the Gaadhoo Koa is thatalternative channels must be used for large vessels to enter the atoll. This is likelyto require:

Additional navigation marking to be provided on alternate channels

Revision of recommended navigation procedures

Possible revision of pilot boarding stations

Revision of maritime charts to show airdraft restriction

5.2.4

Floating Bridge

For the floating bridge option it is important for the stability of the structure tokeep the bridge relatively low. If the centre of gravity is too high then the

pontoons will become unstable and could invert.

In general, the soffit clearance above water is maintained at 5.0m in permanentload conditions which will allow safe passage of vessels up to around four metresin height. This means that only very small vessels can pass such as the resortspeedboats and local ferries.

Because of the need to provide passage for the airport emergency vessels, onespan of the bridge will be provided with a soffit clearance 8.5m above water. Thismay require the pontoons to be increased in size for this particular span.

5.3 Span and Marine Safety

5.3.1 Ship Domain Theory

Whilst the available airdraft beneath the bridge represents a physical constraint tothe size of vessel which can pass under the bridge, the span is related to marinesafety. If the span is too little then vessels will be confined to a narrow channeland are more likely to have to carry out evasive manoeuvres in the vicinity of the

bridge. This in turn leads to a greater risk of ship to ship collision compared to

unrestricted waters.


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One way of assessing the required span is based on ship domain theory [8]. This isthe observation that ships navigate within a safety bubble known as a domainand that when fixed objects or other ships impinge on this domain the ship maycarry out evasive actions.

Figure 30 Ship domain theory

5.3.2 Traditional Bridge Options on Alignment A

Due to the deep water in the Gaadhoo Koa, the minimum span which is underconsideration is approximately 200m. At the same time, the airdraft limits meansthat only small vessels can pass under the bridge.

A span of 200m means that ships with a length less than or equal to around 20mto 25m can safely pass each other under the bridge at free navigation speeds. Thiswill encompass the vast majority of traffic under the bridge including ferries andspeedboats.

Ships up to around 110m length can safely pass under the bridge although theships captain would consider the span to be restricted waters and is likely totravel at reduced speed and pass through the centre of the channel and timing the

passage to avoid ship to ship encounters under the bridge.

The traditional bridge options on Alignment A will cut squarely across the straightnavigation channel in open water where there is good visibility and few vesselswill be making manoeuvres or crossing the channel. The marine risk associatedwith this option given the long span of the structure is very low.

5.3.3

Floating Bridge Option on Alignment CFor the floating bridge option the span will be approximately 100m. However, forthis option the airdraft is also generally significantly lower meaning that only thesmallest vessels (resort speedboats and local ferries) will be able to pass. Based onship domain theory the span will be sufficient for these vessels.

However, the bridge is close to the entrance of harbour areas on both Mal andHulhul Island where vessels may be manoeuvring in different directions.Furthermore, the pontoons of the floating bridge will be relatively restrictive tovisibility and it will not always be obvious which span a particular vessel intendsto pass under. Some vessels may wish to pass obliquely under the bridge.

For these reasons there is a slightly higher degree of marine risk associated withthe floating bridge option on Alignment C.


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5.4 Ship Impact

Bridges in navigable waters must be designed considering the possibility of shipimpact. This means considering the scenarios under which a vessel could becomeaberrant within the vicinity of the bridge (whether due to mechanical failure orhuman error) and could then go on to collide with the bridge.

The forces due to ship impact from large vessels are very significant and can bedisastrous. However, as has been discussed above, the large vessels will no longer

be able to use the Gaadhoo Koa after construction of the bridge so they should notbe navigating in the vicinity of the bridge.

Medium and small vessels may still navigate under or near the bridge and amarine risk assessment needs to be carried out to determine the probability ofdifferent sizes of vessels impacting the bridge, the likely impact speeds andtherefore the ship impact forces that the bridge must be designed for. Possible shipimpact scenarios include:

Vessel becomes aberrant and collides with the piers of the bridge (hull impact)

Oversized vessel attempts to navigate under the bridge and collides with thedeck (mast / deckhouse impact)

Ship at anchorage breaks free of its moorings during a storm and driftstowards the bridge colliding with either pier or deck

The objective of the marine risk assessment will be to determine the necessarynavigation installations and procedure to maintain safety as well as to define theship impact forces which the bridge must be designed for.

5.5

Conclusions

The Maldives is an archipelago and marine traffic is an important aspect ofeveryday life in the islands. Construction of a bridge across the Gaadhoo Koa willhave a significant influence on how vessels navigate around Mal, especially thelarger commercial vessels. However, due to the large number of entries into theatoll it has been confirmed by key stakeholders that there will be no adverseimpact to marine operations if appropriate additional navigation aids are providedfor shipping using alternate channels.

All bridge options will provide sufficient airdraft for resort speedboats, local

ferries and the airport firefighting vessel to pass under the bridge and someoptions will provide greater airdraft to allow slightly larger vessels to pass.

The span of all bridge options is considered sufficient for safe navigation but thelocation of the floating bridge on Alignment Option C is slightly less favourablethan Alignment Option A and may cause some navigation conflicts.

For all bridge options, a marine risk assessment will be required to determine thenecessary navigation installations and procedure to maintain safety as well as todefine the ship impact forces which the bridge must be designed for. Since largeocean going vessels will not pass under the bridge the ship impact forces arelikely to be manageable. However, the possibility of a large vessel breaking freeof its anchorage and drifting into the bridge does need to be considered.


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6

Environmental Issues

6.1 Introduction

The purpose of this section is to provide a preliminary environmental assessmentof the proposed bridge options with respect to ecology, water quality, air qualityand noise. Relevant environmental legislations, guidelines and environmental

baseline information are collated. Key environmental impacts during theconstruction and operation of the proposed road and bridge link are identified.Design approaches to avoid and minimize potential environmental impacts,mitigation measures to address the potential impacts and further investigations arerecommended, where applicable.

It should be noted that this section only presents a preliminary assessment anddetailed studies and/or assessments need to be carried out during later design

stages.

6.2 Environmental Legislation, Guidelines, Policiesand International Conventions

6.2.1 Relevant Environmental Legislation and Guidelines

Environmental Protection and Preservation Act of MaldivesThe Articles of the Environmental Protection and Preservation Act (Act No.4/1993) addresses the following aspects of environmental management:

Guidelines and advice on environmental protection shall be provided by theconcerned government authorities;

Formulating policies, rules and regulations for protection and conservation ofthe environment in areas that do not already have a designated governmentauthority already carrying out such functions shall be carried out by theMinistry of Environment, Energy and Water (MEEW);

Identifying and registering protected areas and natural reserves and drawingup of rules and regulations for their protection and preservation;

An Environmental Impact Assessment shall be submitted to MEEW beforeimplementing any developing project that may have a potential impact on the

environment; Projects that have any undesirable impact on the environment shall be

terminated without compensation;

Disposal of waste, oil, poisonous substances and other harmful substanceswithin the territory of the Republic of Maldives is prohibited. Waste shall bedisposed of only in the areas designated for the purpose by the government;

Hazardous / Toxic or Nuclear Wastes shall not be disposed anywhere withinthe territory of the country. Permission should be obtained for any trans-

boundary movement of such wastes through the territory of Maldives;

The Penalty for Breaking the Law and Damaging the Environment shall be

specified;


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The government of the Maldives reserves the right to claim compensation forall damages that are caused by activities that are detrimental to theenvironment.

Environmental Impact Assessment Regulation 2007

The MEEW issued the EIA Regulation in May 2007 which guides the undertakingof the Environmental Impact Assessment/Initial Environmental Examination(EIA/IEE) process in the Maldives. The EIA Regulation provides acomprehensive outline of the EIA/IEE process beginning from the application tothe details of the contents, the minimum requirements, roles and responsibilitiesof the consultants and proponents, the format of the EIA/IEE report etc.

Ban on Coral MiningCoral mining from the house reef and the atoll rim has been banned through adirective from the Presidents Office dated 26thSeptember 1990. Coral is

prohibited to be mined at any stage of the project.

Guidelines for Domestic Wastewater DisposalDeveloped by the Maldives Water and Sanitation Authority and implemented bythe Environment Protection Agency, this guideline serves to improve public heath

by regulating the disposal of domestic wastewater and therefore providing acleaner and safer environment through improved sanitation. When handlingwastewater from construction workforce these guidelines should be considered.

Ambient Air / Noise and Water Quality StandardsThe Republic of Maldives lacks the necessary environmental standards for themeasurement of ambient air, noise and water quality. Therefore, standards of theWorld Health Organization (WHO), those of international recognition, orstandards of developed countries should be used.

6.2.2

Relevant Policies

National Energy PolicyThe National Energy Policy looks at existing and emerging energy issues andconstraints of the country. With a focus on sustainable supply and consumption,the policy also addresses issues of the environment, renewable energy and energyefficiency. According to the policy document, 3% of energy is from biomass andsolar and the remainder is from refined petroleum products. Diesel fuel accountsfor 83% of the total energy consumption in the Maldives.

Carbon Neutral by 2020In March 2009, President Nasheed announced the target to make Maldives carbonneutral by 2020. Hence, in the implementation of the project, careful attentionneeds to be given to ensure energy efficiency and reduce transport related fuelconsumption.

National Adaptation Programme of Action (NAPA)The adaptation policies and strategies of the Maldives are given in the Maldives

National Adaptation Programme of Action [10]. The first component of theMaldives Adaptation Framework is climate change-related hazards. Theseinclude sea level rise, precipitation, temperature and extreme events.


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6.2.3 International Conventions

Convention on Biological DiversityThe Maldives is a party to the United Nations Convention on BiologicalDiversity. The objective of the convention includes the following: theconservation of biological diversity, the sustainable use of its components and thefair and equitable sharing of the benefits arising out of the utilization of geneticresources, including by appropriate access to genetic resources and by appropriatetransfer of relevant technologies, taking into account all rig

Male Hulhule Bridge Feasibility Report Aug 2011- Final

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