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Atoll Reclamation, an Option?
Robert Smith, Geoscience Division PC
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Atoll Provinces of the Tropical Pacific Ocean
From Dickinson 2009 published in GSA
Numbers vary for atolls globally - 1952 E.H Bryan jnr reported some 400 atolls
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Typical Atoll Issues
• Land shortage and scarcity,• Increasing land tenure problems (disputes on
ownership, boundaries, and leases),• Increased demand for shelter and housing,• Increasing numbers of urban squatters and
emergence of ‘urban poor’,• Groundwater and lagoon pollution through leaching
of sewage and other waste,• ad hoc garbage and waste disposal• Increasing environmental degradation• Contamination of fish from human excrement,
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Vulnerabilities with respect to climate variability and change
• Rising mean sea level is only one of several potential effects ofchanging global climate. Other factors that will affect the coastsof islands in atoll settings include:
• Changing storm patterns (e.g. cyclone frequency anddistribution), wind patterns,
• Sea-surface temperature (SST). Impacts on sediment supplycoral and other species.
• Changes in rainfall that effect rainwater harvesting• Changes in rainfall that impact ground water recharge
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Global average sea level versus Regional sea level .
Global average sea level is affected by changes in net ocean heat content and land based ice melt which are strongly influenced by warming trends.
Regional sea level variations largely result from changes in wind patterns and ocean circulation that are components of natural climate variability.
Source :Pages –AGU publication 2016 Interglacials past 800,00 yrs
Regional sea level trends
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January 2016- monthly summary Federated States of Micronesia recorded its lowest monthly sea level on record, while monthly sea levels at many other stations fell to their lowest levels in 5 years. Sea level anomalies below -20 cm were observed at Federated States of Micronesia, Papua New Guinea, Solomon Islands and Tuvalu.
April -2016-Small storm surges were observed at Vanuatu, Fiji and Tonga in early April, brought about by strong winds and low barometric pressure from Tropical Cyclone Zena. Tropical Cyclone Amos caused a small surge at Samoa on 23rd April
April 2016 Sea levels remained lower than normal at many stations in connection with the 2015-2016 El Niño, with monthly anomalies around -30 cm at Solomon Islands and lower than -10 cm at PNG, Kiribati, Nauru and Tuvalu. Sea levels at Marshall Islands and FSM were near normal for this time of year.
Source: Climate and Ocean support programme in the Pacific monthly reports. Pacific Sea Level Monitoring Project BOM
8Star-2016 Source: Climate and Ocean support programme in the Pacific monthly reports. Pacific Sea Level Monitoring Project BOM
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Coastal Protection and Reclamation• Extensive sections of the ocean and lagoon shoreline have been modified by
construction of sorts
• This is partly in response to erosion threats and partly in the process of reclaiming land a valuable commodity traditionally
• Infrastructure under threat from coastal erosion – e.g. hospital, schools
• Studies to date show 90% of the coastline is under some form of attack
Ebye -17102012 Tarawa Betio-Bairiki causeway 2014Majuro -2012
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So why Reclamation ?
Lets consider possible options with respect to the aforementioned issues
• Do nothing• Coastal protection of existing islands – expensive, no new land• Migration cultural ties make leaving very difficult• Decentralisation• Reclamation - new land
water resources –engineered water tablereduces population pressure for accommodationcan lead to improved economic opportunitiescommunity recreational space (ncd’s)
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Maldives26 Atolls along a 860km long chain north south in the Indian Ocean with some 1,190 low lying coral islands.Administratively divided into 20 atolls -358 islands inhabited, capital being MalePopulation 341,000 (2014)Tourism receipts in 2014 $ 2.6 billion US
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Male and Hulhumale 21-012001
Male and Hulhumale 14-12-2015
Hulhumale : mid 1990s, the idea of creatingan artificial island from an existing lagoon for afuturistic urban city which would accommodatethe excessive population of the central region was born
Phase I of Hulhumalé reclamation, 188 hectares,began on 16th October 1997 and was completedby June 2002.2013, Hulhumalé Phase I has reached a populationof 30,000, which is the halfway mark of the target population of 60,000
Phase II of the Hulhumalé project, consisting of 240 hectares, is targeting a total population
of 100,000.
Hulhumale
Male Scale bar 3km
Atoll reclamationHaa Dhaalu Atoll-Kulhudhuffushi Island
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Kulhudhuffushi 2001 Kulhudhuffushi 2014Kulhudhuffushi 2006
Population 8224Length 2.9kmWidth 1.8km
Geographical Atoll name Thiladhunmathi Atoll
Original island 200 hectaresMTCC added 9 hectaresBoskalis International bv 28 hectares Cost NZ$10m
Newly reclaimed land to be used for residential, commercial or industrial and social facilities
The project aim was to create a safer and larger island for the Vilufu-shi residents, who were temporarily evacuated to Buruni island, as well as for the population of some other smaller nearby islands. The project involved in increasing the level of a part of the existing island and the reclamation of a part of the surrounding shallow reef flats, to provide extra land for residential purposes. The surface of the island was increased from 16ha to 62 ha and raised an additional 1.4 m above MSL. In addition, construction of about 2000 m. of revetment around the is-land at 2.4 m above MSL, and a new fishing harbour. The harbour will include 350 m. of breakwater and 350 m. of quay wall. The required amount of sand dredged was1.1 million m3. Dredging was completed in 5 weeks. Equipment used included a medium sized cutter suction dredger, a pipeline system and various bulldozers and wheel loaders.
– http://www.eia.nl/en/publications/advisory-reports/060-i14Star-2016
Vilufushi Island –Thaa Atoll Maldives
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Vilufushi Island 13-01-2016
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Tarawa Atoll• Centred at 173 E and 1 25
N
• Shallow with an average depth of 7m, large tidal flats
• Total land area about 3100 hectares ( 31km2)
• Lagoon 533.91km2.
• Of the total country population 48.7% reside in South Tarawa (2010 census in 1995 37.5%)
• Projected by 2030 107,000
• South Tarawa in 2010, 3184 persons per km2
• source http://www.climate.gov.ki/wp-
content/uploads/2013/01/6_SOUTH-TARAWA-revised-2012.pdf
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Tarawa Atoll Issues
• Failing Infrastructure - Water and Sanitation
• Sand and gravel extraction
• Planning and Urban Development
• Population pressures are exacerbated by the very limited land resources, of the 1521 Ha some 300 Ha are fish ponds in Temaiku
• Narrow island widths and land scarcity – small changes in coastline become very significant.
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Previous land reclamation projects in TarawaTemiaku Blight 1968 a senior agriculturalofficer Mr R.T.Hubbard mooted the idea of closingoff Temaiku Bight to reclaim tidal lagoonal tidal flats an area 300Ha. This worked commenced in 1970
Betio wharf and container yard
The new Parliament location
1998 2013
19982013
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Options for reclamation
36 Ha -1.5 million m3 ht +3m
Temaiku –area -247 Ha
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Republic of the Marshall Islands
Kwajalein
Majuro
Ebeye
South end of Ebeye island showing the USCG Loran station first established here in 1950 and decommissioned 31 Dec 1977 Source http://www.loran-history.info/kwajalein/kwajalein.htm
Beach rock exposedShoreline features indicating that erosion
persisted earlier than 1970.
Infrastructure remains ?
Sand
spit
Lagoon shoreline
East
Lagoon reef flat
West
West
http://www.fayeandsteve.com/Kwaj%20aerial%20views.htm
N
Beach rock
Borrow-pits
Peace Park
Fuel tanks
Seawall and fence line of Power plant
Lagoon
Ocean
East
Remnant toe of coastline ??
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Reclaim areas 43 Ha
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Funafuti Atoll 1943 Tuvalu
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Represented 8% of islandRequired 250, 000 m3
Work required included:• Sediment type • Resources identification within specs of dredging parameters• UXO surveys for potential hazards
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Borrow pit 2
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1Ha 109Ha
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Conclusions• Significant uncertainties remain, particularly related to the magnitude and rate of the
ice-sheet contribution for the 21st century and beyond, the regional distribution of sea level rise, and the regional changes in storm frequency and intensity ( a closing comment in chapter of IPCC Chp 13 WGAR15)
• PI leaders need to act now
• Once developed, the potential for agricultural and recreational development on par with larger islands can be realised.
• Increase in STATE Land Ownership
• Increased base value to a potential tourism market
• Development of community recreational facilties – (ncd’s)
• Strengthening planning and urban Management
• Increased resilience and sustainability
• Engineered water lenses leading to sustainability in water resources possible
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VinakaPicture courtesy of Peter Olivier Calibre Consulting