The Upper Tisa Valley. Preparatory proposal for Ramsay

Figure 8. Distribution of precipitation in mm in the catchment area of the Upper Tisa
on the basis of an average over 40 years
slopes predominantly rich in precipitation are the ones that lie in a right angle to the
winds carrying precipitation. Such mountain ranges are in NW-SE and N-S directions
(Figure 8).
The change in the extent of wetness within a year essentially determines the
flow of the rivers. Surface water input determining the flow of the rivers and the
seasonal changes occurring in the catchment area cause significant regional
differences (Figures 9-12).
In the Northeastern Carpathians, surface water in the winter months
(December, January, February) is mainly from snowfall. Snow accumulation increases
with altitude and, regarding the distribution of water input, it causes maximal activity
of precipitation in December in the catchment area. Orographical factors exert considerable
influence on quantitative changes, as in the above mountainous area lower
than 15 mm of water-input distribution can be observed at altitudes above 1600 m.
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