NORSK ENTOMOLOGISK TIDSSKRIFT - Norsk entomologisk forening

104 Albert Lzllelznr~trner
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JAN. FEBR. MARCH APRIL MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.
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Fig. 2-4. Fig. 2. Thc annual water flow, in Suldalsligen. Fig. 3. Section
of Suldalslkgen, The bottom ticondion and crossprofil. Fig. 4. Section of
Storelva. The bottom condition and crossprofil.
Description of the Watercourses
SuldalslAgen (fig. 1,l) has been described by A. Lillehammer
(1964 and 1965). Its water supply comes mainly from the melting
snow on the high mountain plateau, the greatest flow of watcr
being in the summer months (fig. 2). The temperature, therefore,
is comparatively low at the and of June when the melting of the
snow culminates; there upon, the temperature rises until August
when it is at its highest.
Storelva (fig. 1,2) flows through the district of Sauda. Its
precipitation area is 358 m2. It is a short but well-filled watercourse
and obtains its natural intake from the melting snow on
the highland plateau. At Storlidam, however, this is all directed
into a pipe-line and carried to the power station at the fjord-side.
There is thus left the intake from the lower mountain areas where
the melting of the snow takes place mainly in the Spring. The
flow of water has a tendency to decrease in July and August. During
this period the water level can be so very low that, occasionally,
the water just about flows. Moss vegetation found included
Fontinalis dalecarlica and Marsupella emarginnta. Algae vegetation
is also common in some parts of the river.
Whereas the size of the stones in Suldalsl5gen (fig. 3) is very
uniform, in Storelva (fig. 4) there is considerable variation.
Suldalslagen (fig. 5) therefore flows more evenly and more quietly
than Storelva where the conditions of the current are quite