4 Isotope Geochemistry in the Environment
67
t,, 9 ~
_?'~_ :,..
,
soo
,
Fig. 4.14. Observation wells (PS. WS, W7, OWl close to the Danube river. (Stichler et a[.
1986)
Island
i
'
"
i Observation
Danube I
WeLL
= ! welL
C,.~(t)
1',
C=,(tl
po
I', (1-p)O
I C,ut (t)
C,n, (t) ~'~~_
.. ,
~
~ }
C'nz ( t
) :
pO
C,uh (I) r~:tz ~t )
CT" p.~O
Fig. 4.15, Schematic flow model illustrating the hydrologic situation in the area of
investigation. Cinl(t): Tracer flux from Danube river; Cow(t): Tracer flux from
groundwater observed in observation well OW; Cout(t): Tracer concentration in
observation wells PS, W5 or W7; p: fraction of the total flow rate Q; T=V/Q=average
transit time of lhe groundwater (T O for Danube river, T o' for groundwater; V:volume of the
migrating groundwater. (Stichler r al. 1986)
In the Alpine region, both snow and rain waters are strongly fractionated,
isotopically speaking, because of repeated evaporation and condensation events as
altitude is gained (see Fig. 2.9). 2. The fluctuations in the isotopic composition of
river water can be directly related to climatically forced temperature fluctuations.
Enhanced Summer temperatures mean that t60 is preferentially incorporated into