1. CLIMATE CHANGE Consequences for Alpine Lakes & Management
20. May 2011
Mid-Term Conference Sarnico

2. Mid-Term Conference Sarnico
First results on Austrian lakes Liselotte SCHULZ & Till HARUM Roswitha FRESNER, Albrecht LEIS, Georg SANTNER
20. May 2011
Mid-Term Conference Sarnico

3. SILMAS Questions Climatic changes influenced our lakes in the past ?
Are there impacts on water temperature, water household
and water quality ?
What could happen to the lakes in the future ?

4. Frankreich
Deutschland
Italien

5. Lakes investigated:
Ossiacher See
Wörthersee
Klopeiner See

6. SILMAS Investigations
Analysis of long term data (1930 – 2011) from climatology, hydrology & water quality parameters
additional collection of actual water temperature data & chemical- biological data
Determination of inflow, outflow and residence time of lake water by using environmental isotopes

7. Hydrological modelling
SILMAS
Hydrological modelling
Calibration of rainfall-runoff-models on the basis of measured data
Simulation of past water balance changes
Simulation of future scenarios

8. SILMAS Aims Rainfall-runoff model for the lakes catchment RAINFALL
POTENTIAL EVAPORATION
MODEL
PARAMETERS
RUNOFF COMPONENTS
EVAPORATION
RECHARGE

9. SILMAS First Results Air temperature & Precipitation & Evaporation Discharge of In- and Outflow Water Temperature Environmental Isotopes

10. Air temperature & Precipitation & Evaporation
HISTALP station Klagenfurt
Air temperature & Precipitation & Evaporation
HISTALP station Klagenfurt

11. Discharge of In- and Outflow
Lake: Ossiacher See
Discharge of In- and Outflow

12. Annual Water Temperature Development
Lake: Klopeiner See
Annual Water Temperature Development

13. Water Temperature Lake Ossiacher See

14. Annual Average Water Temperature

15. Annual Average Water Temperature

16. Annual Average Water Temperature
Klopeiner See

17. Stable isotopes Oxygen-18 and Deuterium
Origin (source) of water in the lake
Mixing processes
Age of the water
Evaporation processes in lakes
Deliver information about:

18. Residence time of deeper lake water
Determination:
how long does it take for rain water to reach the deeper zone of a lake
Bomb peak: Tritium in precipitation as tracer for residence time in lakes: The 3H-3He method
Tritium concentration in precipitation

19. Mean residence time of lake water in the deepest zones of the Austrian lakes
Wörthersee
Ossiacher See
Klopeinersee

20. Output and Deliverables:
Development of a climate change related modelling approach which can be used to interpret changes of water balance and circulation behaviour and their influence on water quality
Validation of the vulnerability concerning nutrient loading related to water balance and residence time
Instrument for the decision support for lake managers to fulfil the criteria of the WFD to reach or save the good ecological status

21. critical evaluation of permissions for interventions on lakes:
bank protection works
pontoons
marinas and boat license
extraction of water
drinking water supply,
irrigation, hydropower,
heat pump …

22. Proof and advantage of global warming Thank you for attention
Die Seen werden und gegenüber Belastungen sensibler und daher müssen die Manager sorgfältiger und kritischer Eingriffe in das Ökosystem bewerten.