Transcript
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Sustainable water resources?
towards a better understanding of resource security
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Dr Alan MacDonald amm@bgs.ac.uk
when are water resources part of the problem?
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Absolute water availability and quality
water security affected by:
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Access to water (e.g. type & number of sources)
Demand for water
Source: Calow et al. 2010
Water resources...
Dry season
© NERC All rights reserved Source: MacDonald, Calow 2009
0
7 – 11
Months
1 – 3
4 – 6
12
Natural storage
So where does most rural water come from?
... groundwater
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Naturally protected
Generally good natural quality
Can meet dispersed rural demand
Volumes of groundwater storage
1. Overall storage high: 0.5 ‐1 million km3
2. 10 times more than rainfall
3. 100 times more than annual renewable freshwater
4 U l di ib d
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4. Unevenly distributed
2
Larger sedimentary aquifers
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More complicated sedimentary rocks
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Crystalline basement
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The groundwater can be mapped and conditions predicted.
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Choosing technology
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Techniques for evaluation
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3
Water quality
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24o
25o
26o
27o
Arsenic( g L--1)
<1010-5050-200>200
INDIA
Sampling
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88o 89o 90o 91o 92o 93o20o
21o
22o
23o
'Groundwater Studies of Arsenic Contamination in Bangladesh'DPHE/BGS/DFID (2000)
INDIA
200 km
n=3546
01020304050
%
What about renewability?
Generally enough recharge for rural water supply
More water problematic
Importance of natural t
Recharge vs rainfall for 80 African studies
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stores
Monitoring
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60 009070 80 10
Technologically easy – but needs to be in the right location.
Continuity – the importance of long term monitoring
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Summary – water resources
Know the water resources and demand
Match technology to water environment
Construct water points properly and in most productive parts of the aquifers
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p p q
Collect and keep baseline data when constructed
Monitor change
There are techniques and people out there – use them !
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