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110 Zofia Kaczorowska

In order to present the results of certain larger physiographic units linked by common features, their altitude a. s. 1. has been taken as chief criterion. The 300 m. isohypse constitutes the boundary between the „Polish Lowland“ and the „Polish Carpathians“. The author compared data from 22 stations representing 8 of the above discussed regions, embracing the Polish Lowland, and from 5 stations from the remaining regions embracing the Beskides and Podhale, and presented these data in Table 23 and Figurę 12 Here, she also added her computation comprising all of Poland.

On the basis of the above research, the author puts forth the following conclusions:

1.    The investigation of the trends of precipitation in Poland seems to in-dicate that the insignificant and statistically poorly corroborated difference in precipitation fails to be the cause of the apparent water shortage.

2.    The analysis of the freąuency of average, dry and wet years and seasons, including their gradation, observed during a 60-year period in the 11 regions of Poland, yields a rather chaotic picture. Generally speaking, water defi-ciency predominates as to the number of instances, while water excess — as to intensity.

3.    The comparison of the freąuency of average, dry and wet years and seasons for the Polish Lowland and for the mountains indicates:

a)    eąuality in the number of seasons with average amounts of precipitation, as well as all dry and wet seasons to exist in the Polish Lowland,

b)    a preponderance of instances of deficiences over averages — especially during summer, autumn and winter — to exist in Southern Poland.

4.    An analogous comparison for all of Poland shows:

a)    a high predominance of average amounts of precipitation and a slight prevalence of excesses over deficiencies in the yearly average,

b)    during spring and summer, a proportion exactly balanced between instances of deficiency and excess,

c)    during autumn and winter, an increase in the number of deficiencies in precipitation against a decrease in instances of average precipitation,

d)    in the class of highest deviations (> 50%), excessively wet periods occur in all seasons morę freąuently than excessively dry periods. The autumn is the season of greatest contrasts.

5.    It seems that the cause of the commonly felt shortage of water should be looked for not in a decrease of precipitation but rather in changes within other elements of the water balance, as well as in the manner of water uti-lization in view of changes in hydrological conditions brought about by na-tural or artificial agencies.