How fast does groundwater move, or how
old is it?
...And why do we care?
Pradeep Aggarwal
Programme Manager, Water Resources
Andy Garner
Water Resources Management Specialist

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Groundwater moves much, much
slower than river water
River flow ­ meters/sec;
even the largest rivers are
renewed in a couple of
weeks
Groundwater ­ mil imeter
to meter/year;
months to thousands of
years old

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Can we taste the age of water from
Europe, Africa and Australia?
Vienna
Kufra
Alice Springs

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What does it mean if groundwater is old?:

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If groundwater is old, the reservoir or
aquifer is not being refil ed!

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Recharge

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0
Present day rain
-5
Great Artesian Basin
Australia
-10
Kufra, Libya
O
x
y
g
e
n

I
s
o
t
o
p
e

R
a
t
i
o

S
c
a
l
e
Vienna Tap water
and Schneeberg Rain
-15 0
20000
40000
60000
80000
100000
120000
140000
Age (years)

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