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ŠUMARSKI LIST 13/2005 str. 248     <-- 248 -->        PDF

1. Pilaš. T. Gojmcrac. B. Vrbek, T. Dubravac: ENHANCEMENTS IN THE GROUNDWATER MONITORING ... Šumarski list SUPLEMENT (2005). 245-246
ENHANCEMENTS IN THE GROUNDWATER MONITORING SYSTEM
IN LOWLAND FOREST ECOSYSTEMS IN CROATIA
BY USING GIS AND GEOSTATISTICS


Ivan PILAŠ, Tihomira GOJMERAC,
Boris VRBEK, Tomislav DUBRAVAC


SUMMARY: The main ecological factor, which determines the lowland i.e.


floodplain forest ecosystems is the abundance of soil water. High groundwater
tables and the groundwater regime on these sites have a key role in maintaining
sufficiently high soil water content. Recent climate and anthropogenic
changes in the water regime have had a strong influence on the stability of
these ecosystems which have become more vulnerable in respect to other
abiotic and biotic factors. Decreasing groundwater tables due to global climate
changes and local hydrotechnical activities reflect on the productivity of
these forests. This was the main reason that foresters established long-term
groundwater monitoring studies so as to obtain deeper knowledge of these issues.
The monitoring of groundwater levels has been established in main forest
complexes where measurements have been taken at a large number of
piezometric stations on a weekly basis. Up to the present, series of data have
been collected for more than a decade. In this paper the results and analysis
of collected groundwater monitoring data from different forest complexes;
Kupčina, Česma and Našice area will be presented. Enhancements of data
analysis using GIS and geostatistics will be presented mostly in terms of


J. Analysing
differences in the groundwater regimes between these
forest complexses
2.
Analysing the spatial influence of seasonal drought on groundwater
tables
3.
A spatio-temporal analysis of groundwater decrease
The differences in the groundwater regimes in these forest areas are linked
to their position either in the pluviothermic regime of Sava River catchment
or glacial regime of Drava River catchment. Spatial analysis of the groundwater
series was made using GRASS (Geographical Resources Analysis Support
System), IDW (Inverse distance weighted average), interpolation and
geostatstical analysis and predictions by the geostatistical program Gstat based
on Linux.


In addition, in this paper preliminary results of particular groundwater
chemistry parameters analysed from samples taken from piezometers in the
Cesma forest area will be presented. Groundwater chemistry is a further step
to the enhancement of the existing forest groundwater monitoring network in
terms of its interdisciplinary use.


Data gathering from piezometric sets also present a major problem because
of the high cost of traditional manual groundwater measurements. Therefore
the current status of development of new digital cost effective groundwa


ter data logger will be presented which in the future could fully replace field
monitoring personnel.
Key words: lowland forest ecosystems, groundwater, piezometers, GIS,
geostatistics