Transcript Vulnerability of freshwater lenses on Tarawa (The role of

Vulnerability of
freshwater lenses
on Tarawa
(the role of hydrological monitoring in
determining sustainable yield.)
Outline of the presentation
1) HISTORY OF GROUNDWATER
DEVELOPMENT.
a) 1960’s investigations and findings
b) 1999’s and 2000’s investigation and
findings
2) DISCUSSIONS/CONCLUSION
Lessons learnt
Brief on Kiribati
Kingdom of Tonga
Map of Tarawa
Aerial Photo of Bonriki water reserves
Some basic facts about Climate Change
By the year 2050
• Sea level is likely to increase by 23-43 cm
•Air temp between 0.9-1.3 deg cent.
•Change in rainfall between –10.7% and 7.1 %
•ENSO – more of it.
WORLD BANK STUDY (2000)
By the Year 2050
•If the rainfall decreases by 10%
•If sea level rises by 0.4m
•If the island width is reduced by inundation
•Groundwater thickness would
decrease by up to 38%
•US$0.7m to $1.4 million per year
Boreholes
History of groundwater
development
1960’s and 1970’s
 Kirk, Grundy and Partners (1961)
 Wilton and Bell, Dobbie and Partners
(1967)
 Mather in 1973
 Wagner in 1977

To name a few
Findings
Some (Richard etc) said that
Bonriki could not sustain itself
while others (DHC) said that
Bonriki and Buota could
supply 750m3/day and
250m3/day.
1990’s and 2000
 Tony Falkland, Ian White and others
Findings
 Bonriki and Buota could yield at
least 1000 m3/day and 300 m3/day
respectively.
Discussion/Conclusion
A number
of pacific countries rely
on groundwater for freshwater
Climate change will affect our
groundwater
Based on years of experiences,
borehole monitoring is probably the
best way to monitor groundwater
Initial Cost borehole:
AUS$100,000 - $200,000
Cost due Climate Change:
US$0.7m - $1.4 million