Environmental Engineering Reference
In-Depth Information
Fig. 5.14 Example of old channel
“
penetrating
”
the
fl
floodplain (Bia
ł
ka river)
the Por
bianka streamchannel had increased from47 to 62%. Currently the migration
zone of the ramp regulated river reaches 50
ę
60 m and the channel width varies
from 25 to 30 m. Before regulation works it used to be in the range of 70
-
150 m. One
-
of the last braided rivers in Polish Carpathians is Bia
ka river in the reach from the
Krempachy gorge to its outlet. This river, close to nature, still develops multichannel
system in the width of 100
ł
250 m (Struzynski et al.
2011
). Additional channel of
braided river can penetrate the
-
floodplain, locally indicating the water-table
(Fig.
5.14
). Within such ponds, many species can pass the larval period (i.e.,
macrozoobenthos, tadpoles). Within lower run of Por
fl
bianka stream there is still a
possibility of restoring similar areas. One of the mechanisms which could intensify
the morphological transformations is the bedload transport. Braided rivers are
heavily loaded by this material. Unfortunately, within the upper sections of the
stream, heavy regulation works were performed, blocking the sediment supply.
The Czarny Dunajec River within the mentioned reach flows between regulates
sections. This in
ę
fluvial processes which transform the river from curvy
to a braided river and closer to the town of Nowy Targ an island
fl
uences the
fl
braided channel.
Through the braided part, the Nature 2,000 areas cross the valley from its left to the
right side. Within the valley, multiple marks of the land-transformed oxbow lakes
can be found. The incision of the riverbed exceeds 1.5 m (Fig.
5.15
).
This signi
—
es that erosion processes are still taking place, however the bedrock
has not been reached yet and the braided character of the Czarny Dunajec River is
still preserved. The main danger for this reach is the exploitation of the bed material
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