18 Waterways in Poland – The History, Present State and Future
365
Thus the shortcoming of Polish waterways of classes IV and V is not only their
total length but a far-reaching fragmentation. Although they meet the conditions
imposed on waterways of international importance, their role, due to the lack of
connections to the European network, can only be local [6].
18.4 Navigation Traffic on Inland Waterways in Poland
18.4.1 Influence of Water Levels on Navigation Traffic
Intensity
Freely flowing rivers, having a predominant share in the total length of waterways
in Poland, are subject to seasonal fluctuations in water levels, resulting from their
natural hydrological regime. Both periods of too high and too low water levels are
a limitation for inland navigation (Figs. 18.2 and 18.3). Floods in the Vistula and
Oder basins may have different origins. They are caused by spring and winter thaws
(especially in lowland areas), long-lasting and intense rainfall (upland and foothill
areas), but also can be caused by sea waters during storms, blocking the free flow of
rivers and causing backwater. Too high water levels make it difficult to use waterways,
especially in places where they intersect with engineering structures (e.g., bridges,
pipelines, power cables, etc.). Elevated water levels, apart from flood hazards, are a
significant obstacle to shipping, mainly due to decreased maneuverability of vessels
and smaller vertical clearances under bridges [7]. In the case when the clearance
between them and the water level at the highest shipping water (WW ˙
Z) exceeds
the minimum value for a given waterway class, this causes stopping the navigation.
However, relatively high floods are hydrological phenomena occurring relatively
Fig. 18.2 The river bar in
the central part of the Vistula
river bed in Grudzi˛ adz
during low water levels in
2015 (K. Kubiak-Wójcicka)
365
Thus the shortcoming of Polish waterways of classes IV and V is not only their
total length but a far-reaching fragmentation. Although they meet the conditions
imposed on waterways of international importance, their role, due to the lack of
connections to the European network, can only be local [6].
18.4 Navigation Traffic on Inland Waterways in Poland
18.4.1 Influence of Water Levels on Navigation Traffic
Intensity
Freely flowing rivers, having a predominant share in the total length of waterways
in Poland, are subject to seasonal fluctuations in water levels, resulting from their
natural hydrological regime. Both periods of too high and too low water levels are
a limitation for inland navigation (Figs. 18.2 and 18.3). Floods in the Vistula and
Oder basins may have different origins. They are caused by spring and winter thaws
(especially in lowland areas), long-lasting and intense rainfall (upland and foothill
areas), but also can be caused by sea waters during storms, blocking the free flow of
rivers and causing backwater. Too high water levels make it difficult to use waterways,
especially in places where they intersect with engineering structures (e.g., bridges,
pipelines, power cables, etc.). Elevated water levels, apart from flood hazards, are a
significant obstacle to shipping, mainly due to decreased maneuverability of vessels
and smaller vertical clearances under bridges [7]. In the case when the clearance
between them and the water level at the highest shipping water (WW ˙
Z) exceeds
the minimum value for a given waterway class, this causes stopping the navigation.
However, relatively high floods are hydrological phenomena occurring relatively
Fig. 18.2 The river bar in
the central part of the Vistula
river bed in Grudzi˛ adz
during low water levels in
2015 (K. Kubiak-Wójcicka)