Transcript climate change in alpine area

Effect of climate change in alpine
groundwater environments
Daniel Hunkeler
Centre for Hydrogeology and Geothermics (CHYN)
University of Neuchâtel, Switzerland
Centre for Hydrogeology and Geothermics (CHYN)
Centre d’Hydrogéologie et de Géothermie (CHYN)
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ACTIVITIES/ACKNOWLEDGEMENT
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Swiss National Research Programme PNR61: « Sustainable Water
Management » www.snf.ch/pnr61
EU Project GENESIS (Groundwater and Dependent Ecosystems: NEw
Scientific and Technical BasIS for Assessing Climate Change and
Land-use Impacts on Groundwater Systems)
AlpWaterScarce http://www.alpwaterscarce.eu/
Working group « groundwater and climate change », Swiss Society of
Hydrogeology
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CLIMATE CHANGE IN ALPINE AREA
Temperature
- +1.5°C until 2050
- All models show a positive
trend
Precipitation
- Transition zone between
northern Europe (wetter) and
southern Europe (drier) trends
- High regional and seasonal
differences
2070-2099 relativ to 1980-2009 (A1B)
Ref. Swiss Climate Change Scenarios 2011
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CLIMATE CHANGE IN ALPINE AREA
Temperature
Ref. Swiss Climate Change
Scenarios 2011
Precipitation
More frequent, intense and longer lasting heat spells
More extreme precipitation events
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CLIMATE VARIABILITY IN ALPINE AREA
Hydrol. Atlas der Schweiz,
Tafel 2.6
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HYDROGEOLOGICAL DIVERSITY OF ALPINE AREAS
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EFFECT OF CLIMATE CHANGE ON WATER CYCLE
IN ALPINE AREA
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Decreasing volume of ice in form of glacier
and earlier snow melt (high reliability as
temperature controlled)
-> less water available in late spring/summer
Warmer and likely drier summers
-> higher evapotranspiration
Rain instead of snow
Huss 2010, WRR.
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What is the effect on direct groundwater
recharge and spring discharge?
What is the effect on pumping wells in
alluvial aquifers (river bank filtration)?
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EFFECT OF CLIMATE CHANGE ON
DIRECT GROUNDWATER RECHARGE
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Change in annual distribution of groundwater recharge and possible
decrease in recharge
-> more recharge in winter due to rain instead of snow
-> extension of period with low/no recharge during summer half year
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Calculated recharge 2050
- Selected location in Switzerland at intermediate altitude: -10 to -20%
- AlpWaterScare project Austria: up to -20% of mean annual recharge
(summer partly >40%)
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Impact on groundwater flow systems
- Long term effects on slowly reacting systems
- Short term seasonal effects on systems with low storage
- Smaller superficial systems
- Karst systems
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CASE STUDY TSANFLEURON, SWITZERLAND
Gremaud, 2008. PhD thesis.
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CASE STUDY TSANFLEURON, SWITZERLAND
Gremaud, 2008. PhD thesis.
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CASE STUDY TSANFLEURON
EFFECT ON SPRING DISCHARGE
Gremaud, 2008. PhD thesis.
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EFFECT ON RUNOFF: GLACIATED WATERSHED
Huss et al. 2010, Hydrol. Processes.
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EFFECT ON RUNOFF: NON-GLACIATED WATERSHED
Huss et al. 2010, Hydrol. Processes.
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EFFECT ON PUMPING WELLS RELYING ON BANK FILTRATION
Pumping
wells of
major city
Minimal
stream flow
Centre d’Hydrogéologie et de Géothermie (CHYN)
Low river discharge in late summer
during dry years
-> low groundwater levels in late summer
-> pumping needs to be reduced
-> higher groundwater temperatures
-> effect on water quality
-> higher demand for irrigation
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EFFECT OF GLACIERS ON RUNOFF IN EUROPE
Glacier melt contribution to river
discharge in August
% Aug
1988-2008
2003
Rhine
6.8
14.3
Rhône
29.8
40.3
Po
20.6
27.3
Huss 2010, WRR.
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CONCLUSIONS
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Increase in temperature modifies snow accumulation and melting
Together with increased evapotranspiration during summer half year
this likely leads to
– change in seasonal distribution of groundwater recharge
-> can lead to lower groundwater availability from springs in late
summer
– Modification of flow regime of rivers
-> lower groundwater level in late summer
-> Higher temperatures that could impact water quality
The impact on annual groundwater recharge rate needs further
attention
Locally and temporally groundwater droughts might occur
Issues is mainly seasonal water availability while on annual basis
sufficient water is available
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