Characterizing Aquifers - Hydrogeology: Objectives, Methods, Applications - page 149

7.3.2 Physical and chemical parameters
In the same manner, since recharge and discharge reactions are clearly
marked and due to the frequency of encountering a single outlet, the study
of variations in different physical and chemical parameters can provide
information on the deep structure of the aquifer (see chap. B3-6).
7.4 Speleology
This activity was born from hydrogeology, with the engineer Lindner
who, in order to ensure a water supply for Trieste (Italy), hoped to fi nd
an underground access to the Reka, a river disappearing below ground in
the village of Skojcan (current Slovenia) and re-emerging at the spring of
Timavo near Trieste. Daring explorations thus led him to the Trebiciano
chasm, 327 m below ground, where he fi nally found the underground
river, but remained unable to capture it due to the limits of the available
technology. Shortly afterwards, in 1888, E.A. Martel demonstrated in France
that it was possible to follow the underground path of the Bonheur brook,
which disappears below ground near the village of Camprieu (Gard) and
reemerges a few kilometers away at the Bramabiau spring.
In a little over a century, speleology has made immense progress.
Prospection methods, the clearing of entryways and underground
passageways, and techniques for vertical progression with a single rope
have pushed the limits of exploration, enabling the discovery of thousands
of kilometers of caves and chasms, which are so many examples of the
infi ltration and circulation of water in karst aquifers. Over 550 km of
passageways have been explored in Mammoth Cave (USA), and over
100 km of wells and galleries in Coume Ouarnède (France). Ever-more
daring diving techniques enable the exploration, over kilometers, of
major drainages in the very heart of aquifers. Karst systems are therefore
beginning to be better understood, from their infi ltration surfaces all
the way to their outlets. Current speleologic data is in the process of
modifying our understanding of the peri-Mediterranean karst hydrogeology
(see chap. A9).
Speleology can have several applications in hydrogeology, by
enabling:
￿ knowledge of the geology and geometry of the karst system;
￿ direct access to karst aquifers and submerged drains;
￿ access to underground rivers contributing to the alimentation of the
saturated zone;
￿ access to injection points for tracers.