Use of MEM for Protection of Karst Cave – Example from Križna Jama

International Congress on “Scientific Research in Show Caves”
Škocjanske Jame, September 13-15, 2012
Park Škocjanske jame
Grotta Gigante S.A.G./Velika jama v Briščikih
Karst Research Institute ZRC SAZU
Università degli studi di Trieste, Dipartimento di Matematica e Geoscienze
Use of MEM for Protection of Karst Caves
–
Example from Križna Jama (Slovenia)
Mitja Prelovšek
(Karst Research Institute)
mitja.prelovsek@zrc-sazu.si
Outline
1. Definition of the problem
2. Methodology
3. Results
4. General conclusion and guidelines
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Definition of problem
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Definition of problem
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Definition of problem
Foto: DLKJ
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Definition of problem
Foto: DLKJ
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Definition of problem
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Definition of problem
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Definition of problem
NATURAL PROCESSES
(sinter deposition & dissolution)
ARTIFICIAL PROCESSES –
TOURISTIC USE
(abrasion/corrasion)
1
+
=
0
mm/a
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Methodology
Time span: 2006-(2012) Recording: once per year (during summer)
No. of readings per measurement site: 6
Accuracy: ~0.01 mm per reading
Errors: tip abrasion, MEM thermal shrinkage, mechanical damage
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Methodology
B
C
D
A
B
C
D
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Results
Natural sinter deposition and (natural sinter deposition + artificial abrasion)
tourists per year
375
388
424
525
526
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Results
Artificial abrasion = natural sinter deposition – (natural sinter deposition + artificial abrasion)
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General conclusion and guidelines
Methodology:
•no problem from 1994 – MEM is excellent for such purpose (if rates of processes are
fast enough).
r
range of MEM
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General conclusion and guidelines
Results:
•in the last 6 years use of water part of the cave was sustainable (but especially
upstream is close to the sustainability limit );
•high variation of sinter deposition and abrasion between specific years;
•the highest abrasion is characteristic (a) for sinter dams, (b) where abrasive
sediment is available and (c) where number of tourists is high.
Guidelines for future cave management:
•limitation of touristic tours in water passage due to vulnerable upstream sinter
dams is needed and should be kept at ~350 tourists per year;
•global warming will increase cave vulnerability due to lower sinter deposition rates
and this should be taken into account in future management of Križna Jama.
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