Transcript Slide 1

“Climate change: Footnote in the
groundwater history of urbanized deltas?"
Lessons learned from Dutch experiences
Roelof Stuurman
IGRAC, 5 juni 2008
A dedicated groundwater hydrogeologist living
in a vulnerable polder area (Amstelveen, 5 km
below Amsterdam)
Amstel 0,4 m -NAP
IGRAC, 5 juni 2008
It’s amazing how much the Dutch have changed
the groundwater system during the past 100
years and it is sure this process will continue,
The impact of climate change will be of minor
importance, but can act as the last drop too
much or too little
IGRAC, 5 juni 2008
Impact climate change
1. A decreasing growth of our groundwater stock;
2. Increasing groundwater levels in and around infiltration areas
(glacial hills, dunes),
 Water logging in urban areas around infiltration areas;
3. Water logging in areas with shallow groundwater levels and large
drainage distances
 Many new urban areas built during 1970-2008;
4. Increase of low and ‘hollow’ groundwater levels in summer,
5. Increased need for sprinkler irrigation (15-68 %; now 100 million
m3/y in 15 days; 2-3 times more than all other abstractions at the
same time),
6. Threat of local fresh water lenses in salt areas,
7. Enormous increase of ‘heat and cold storage’ systems
IGRAC, 5 juni 2008
Comparison
1950-2000 vs. 2000-2050
1950-2000
2000-2050 (KNMI)
7-10 cm
13-29 cm
∆ precipitation (P) summer
+2%
-16% tot +5%
∆ precipitation (P) winter
+13%
+3% tot +12%
Mean P deficit (year)
77 mm
151-220 mm
10-75 cm
10-45 cm
(Max 80 cm)
Sea level rise
Subsidence (50 y)
The 2000-2050 predictions refer
to 4 IPCC (KNMI) scenario’s
IGRAC, 5 juni 2008
Dutch fresh groundwater stock still increases
•Now: 1100 billion m3;
• N-ET = 9 billion m3/y;
• N-ET-D = 2,6 billion m3/y;
• Abstraction = 2,6 billion m3/y;
•2100:
• Without CC , SLR and
subsidence growth
of
1,3 %;
• With W+, SLR=85 cm and
subsidence growth
of
1%
• 0.3%= 3 billion m3;
IGRAC, 5 juni 2008
Dutch landscapes
IGRAC, 5 juni 2008
Transect using DINO (DINO; 85.000
deep, 300.000 shallow boreholes)
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Western dune area
‘wash up’
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Deep clay polders
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Salinization: diffuse groundwater discharge vs. boils
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Decreasing ground level
10-45 cm tot 2050
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Bron: Atlas van Nederland/
G.P. van der Ven
Historical analyses
1950-2000
IGRAC, 5 juni 2008
Irrigation: from 100 to 170 million m3/year
[miljoen m3]
Grondwateronttrekking voor beregening in Nederland
Relatie grondwateronttrekking voor beregening
en maximaal neerslagtekort
Onttrekking [miljoen
200
m3]
180
225.0
160
200.0
140
175.0
150.0
120
125.0
100
100.0
80
75.0
60
50.0
40
25.0
20
0.0
0
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
IGRAC, 5 juni 2008
0
25
50
75
100
125
150
Max. neerslagtekort [mm]
175
200
225
250
Impact autonomous development
1. Continuation artificial subsidence creating water
logging and damage to buildings;
2. Development spatial planning;
3. Unknown surprising consequences caused by new
political decisions;
4. Subsurface building;
5. Subsurface sprinkler water storage;
6. Water logging due to stopped groundwater
abstractions;
7. Enormous perforation protecting clay layers;
8. Water logging due to renovation sewerage pipes;
IGRAC, 5 juni 2008
Examples of political decisions in the past with an
unintentional (enormous) impact on the water system
1. Manure legislation:
1. Spreading prohibited during
September 1st till February 1st;
2. Groundwater level is managed
(drained) to allow heavy tractors;
3. Creating low water levels during the
wettest period;
4. Disturbing groundwater conservation
actions;
2. Dairy quota:
1. Meadows (generally high groundwater
levels) are transformed into maize
(corn) field;
2. Using drainage ditches or pipes;
3. Creating decreasing groundwater
levels and peak flows in streams.
IGRAC, 5 juni 2008
PERFORATION OF PROTECTING CLAY LAYERS (1)
Vertical drainage accelerates consolidation
•Creating water logging in seepage areas;
•Creating groundwater pollution risks and
decreased groundwater levels in infiltration
areas.
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Rapidly growth of subsurface building
Already examples of installation pipes with Ø larger than 100 cm at 25 meter depth and many kilometers long
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Example : ‘making dry the Dutch parliamant’
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PERFORATION OF PROTECTING CLAY LAYERS (2)
Installation of closed energy systems
1.
2.
3.
4.
no permission needed;
Use is increasing rapidly;
Bore holes of 80-250 m depth;
For example: in new district
(1200 houses) of the city of
Etten-Leur 2400 boreholes of 80
meters;
5. Fluid used is glycol;
6. Risk of polluting groundwater;
7. Risk of influencing groundwater
levels;
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PERFORATION OF PROTECTING
CLAY LAYERS (3)
subsurface heat & cold storage
2050: 11 billion m3/jaar !!!
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Foundation at risk (wooden piles)
Royal palace at the Dam
(1665, 13659 piles)
1. 500.000 buildings on
wooden piles;
2. 400.000 at risk;
3. Government: “construction
problems”
4. 300.000 can be protected by
groundwater management;
5. 100.000 need action, 5
billion EURO next 20 years;
6. Without action 20-40 billion
after 20 years
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Leaking sewerage systems
The city of Aalsmeer has to pay
Percentage rioolvervanging per decennium
[%]
30
25
20
15
10
5
0
2000
2010
2020
2030
2040
2050
2060
Alarm
Our country is
sinking!
200.000 house
owners at risk
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What when the water factory wins?
Abstraction public water
supply will not increase
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Water annoyance due to successful
water management
Drinkwatervoorziening zal nauwelijks stijgen!
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Comparison other deltas in the world
•Dutch delta unique in the world
•Already 1000 years controlled
by men;
•Before that already 1000 years
no sedimentation;
•People transport more
sediment into the Netherlands
than ever were deposited;
•Deep polders are unique
•Other important world deltas
•Bigger rivers, more sediments;
•Thicker weak sediment layers;
•Stabile substrate rather deep;
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But there is …….
“appointed to our youth as a
tribute to the fellow who
became the symbol of age-long
struggle of the Netherlands
against water”
Are you convinced?
Thank you for your
attention
IGRAC, 5 juni 2008