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Atoll Reclamation, an Option? - Pacific · PDF file Star-2016 3 Typical Atoll Issues • Land shortage and scarcity, • Increasing land tenure problems (disputes on ownership, boundaries,

Mar 19, 2020

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  • 1Star-2016

    Atoll Reclamation, an Option?

    Robert Smith, Geoscience Division PC

  • 2Star-2016

    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

  • 3Star-2016

    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,

  • 4Star-2016

  • 5Star-2016

    Vulnerabilities with respect to climate variability and change

    • Rising mean sea level is only one of several potential effects of changing global climate. Other factors that will affect the coasts of islands in atoll settings include:

    • Changing storm patterns (e.g. cyclone frequency and distribution), wind patterns,

    • Sea-surface temperature (SST). Impacts on sediment supply coral and other species.

    • Changes in rainfall that effect rainwater harvesting • Changes in rainfall that impact ground water recharge

  • 6Star-2016

    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

    7Star-2016

    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

  • 9Star-2016

    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

  • 10Star-2016

    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 table reduces population pressure for accommodation can lead to improved economic opportunities community recreational space (ncd’s)

  • 11Star-2016

    Maldives 26 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 Male Population 341,000 (2014) Tourism receipts in 2014 $ 2.6 billion US

  • 12Star-2016

    Male and Hulhumale 21-012001

    Male and Hulhumale 14-12-2015

    Hulhumale : mid 1990s, the idea of creating an artificial island from an existing lagoon for a futuristic urban city which would accommodate the excessive population of the central region was born

    Phase I of Hulhumalé reclamation, 188 hectares, began on 16th October 1997 and was completed by June 2002. 2013, Hulhumalé Phase I has reached a population of 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 reclamation Haa Dhaalu Atoll-Kulhudhuffushi Island

    13Star-2016

    Kulhudhuffushi 2001 Kulhudhuffushi 2014Kulhudhuffushi 2006

    Population 8224 Length 2.9km Width 1.8km

    Geographical Atoll name Thiladhunmathi Atoll

    Original island 200 hectares MTCC added 9 hectares Boskalis 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-i 14Star-2016

    Vilufushi Island –Thaa Atoll Maldives

  • 15Star-2016

    Vilufushi Island 13-01-2016

  • 16Star-2016

    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

  • 17Star-2016

    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.

  • 18Star-2016

    Previous land reclamation projects in Tarawa Temiaku Blight 1968 a senior agricultural officer Mr R.T.Hubbard mooted the idea of closing off 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

    1998 2013

  • 19Star-2016

    Options for reclamation

    36 Ha -1.5 million m3 ht +3m

    Temaiku –area -247 Ha

  • 20Star-2016

    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 exposed Shoreline 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 ??

  • 24Star-2016

  • 25Star-2016

  • 26Star-2016

    Reclaim areas 43 Ha

  • 27Star-2016

    Funafuti Atoll 1943 Tuvalu

  • 28Star-2016

    Represented 8% of island Required 250, 000 m3

    Work required included: • Sediment type • Resources identification within specs of dredging parameters • UXO surveys for potential hazards

  • 29Star-2016

    Borrow pit 2