Coastal Protection at Tongatapu Island, Tonga

Topics: Coastal management, Ocean, Tonga Pages: 5 (1008 words) Published: October 19, 2013

Coastal Protection


Tongatapu Island, Tonga:

A Report on Initiatives

Nuku'alofa beach seawall (

Prepared for Sylila Monteiro and Antoinette Wessels,
27 May 2011

By: Tattenai Katoanga (ID:1374937);
Mahlon Bonga (ID:1388118);
Pim Slagman (ID:1385439)
1.1 Terms of reference3
1.2 Procedures3
1.3 Background3
3.0 Findings4
3.1 General environmental threats 4
3.2 Situation in Nuku’alofa4
3.3 Situations in other parts of the island5
4.0 Conclusion6
6 References8

1.0 Introduction

1.1 Terms of reference

This report was requested by Sylila Monteiro and Antoinette Wessels, Engineering Communication lecturers at Unitec. It investigates measures taken to protect the coast of Tongatapu Island in Tonga. The report was requested on 6 May 2011, to be submitted by 20 May 2011, with recommendations.

1.2 Procedures

Research of literature and websites as well as documenting of personal observations is to be undertaken on predicted general climatic and environmental influences and on what initiatives in Tongatapu are currently undertaken. 1.3 Background

Tonga consists of a group of 172 low lying islands in the South Pacific Ocean (Lao, 2007). Tongatapu is the main island of the Tongan islands group, located at the southern end of this chain. The low-lying nature and size of Tongatapu means that people are living close to the coast which makes the island vulnerable to changes in sea water levels. 3.0 Findings

Below are described the findings in regards to general climate and the effects on Tongatapu’s coast.

3.1 General environmental threats

Due to global warming water levels are forecast to rise 38 cm from 1990 till 2080. Local measurement has found figures in the order of 10mm a year (Lao, 2007). Another forecast consequence of climate change is that the frequency and severity of cyclones will increase, as well as high sea levels. More than 50% of communities are located within 100 metres of the coast and below 5 metres above sea level (Lao, 2007).

An elevation of 3 metres above high water level (which happened in 1982 during cyclone Isaac) will affect 51.3% of Tongatapu’s population (Lao, 2007). Tonga has a national office for disaster relief and rehabilitation but has yet to prepare a comprehensive national disaster prevention plan. But it seems that every focus is on the urban area of Tonga; Nuku’alofa. 3.2 Situation in Nuku’alofa

Nuku’alofa had a population of 24,310 in the year of 2010 (Country Watch Tonga, 2011). With nearly 25% of the chain’s population living in the capital, which is for over 75 % surrounded by coastline, coastal protection plays an important role for the safety of the people. The vulnerability of the coast became evident when Cyclone Isaac hit in 1982, destroying the shores of Nuku’alofa. After this event a foreshore project in the capital of Nuku'alofa (funded by Japanese Government) was started to minimize the effect of storm surge and soil erosion to low lying area along the coast of the capital (“Tongan reef status”, 2011). In 1986, 3,400m of protective wall was completed (Lao, 2007).

Figure 1. Coastal areas of Tongatapu located below 5 metres above sea level. 3.3 Situations in other parts of the island

In Kanokupolu in Tongatapu’s Western district coastal erosion is fought with a 3km foreshore wall running the length of the village to slow down the wave and wind’s velocity. Money has been raised by residents themselves from local concerts and from donations from non-governmental organisations and kin members in Australia, New Zealand and the U.S. Also, land extensions have been created using silt and gravel excavated from the seabed,

Government funding is limited, efforts go into land planning, creating awareness and designating reserves to restore the natural protective function of the coast, such as coral reefs and mangroves being preserved and grown....

References: Effects of global warming, 2011. Retrieved 18 May 2011 from
Country Watch Tonga, 2011. Retrieved 19 May 2011 from
Lao, F.F.T. (2007). The vulnerability of Tongatapu coastal zone to local impacts of climate
and sea level rise related risks. Unpublished thesis. Waikato University, Hamilton, New Zealand.
Tongan reef status, 2011. Retrieved 18 May 2011 from
Josephine. L., 2008. “Climate Change: A tough reality for Tongan villagers”
Retrieved 14 May 2011 from
Netatua, P.F. & others, 1992. Retrieved 18 May 2011 from “”
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