182
P. Jokiel and P. Tomalski
the seasonality of the Vistula flows became considerably higher than of the Oder, and
the differences were the most pronounced in the 1960s and 1970s. In recent years,
their significance has been declining.
Keywords Flow seasonality · Multiannual changes · Spatial diversity · Big Polish
rivers
10.1 Introduction
The catchment area of the Baltic Sea drains 99.7% of Poland’s territory. Polish
borders are largely hydrographic boundaries, as the country comprises nearly 87%
of the Vistula basin and over 89% of the Oder basin. These are favorable conditions
for rational water management, as the vast majority of Polish water resources origin
within the same country. The basins of the Vistula, the Oder, rivers of the Baltic
Sea coast and the catchments of the Vistula Lagoon and the Szczecin Lagoon drain
nearly 98.9% of Poland’s area. Only 1.1% of the country territory is found within the
catchments of the Niemen (the ´
Swisłocz, the Czarna Ha´ ncza, the Szeszupa rivers),
the Dniester (the Strwi˛ a˙ z river), the Danube (the Czarna Orawa and the Metuje
river) and the Łaba (the Izera river). The springs of two out of four largest Polish
rivers are located outside Poland, i.e. the Oder in the Czech Republic and the Bug
in the Republic of Ukraine. This is one of the reasons why total river flow from
Poland is formed within the area by 12.3% larger than the country’s area and covers
351,028 km
2 . At the same time, only 87% of the country’s river water resources
originate from the territory of Poland.
The Quaternary evolution of the Polish river network resulted in a considerable
asymmetry of left and right basins of major Polish rivers (the Vistula: 72.8% ÷ 27.2%;
the Oder: 70.5% ÷ 29.5%). The same processes caused the main right tributaries of
the Vistula and the Oder (the Narew with the Bug and the Warta) to be longer and have
larger or slightly smaller basins than the main rivers. Another characteristic feature
of the Polish river network, particularly within the Polish Lowlands, are relatively
low drainage divides running across wide ice marginal valleys. One of these is the
main drainage divide separating two largest basins of the Vistula and the Oder.
Due to human pressure and local corrections of the river network, the number
of Polish rivers is difficult to estimate and varies over time. According to IMGW, it
amounts to 4,656 including:
• 2,913 watercourses with catchment area smaller than 50 km
2 – (62.6% of all
rivers),
• 1,553 watercourses with catchment area between 50 km
2 and 500 km
2 – (33% of
all rivers),
• 182 rivers with catchment area between 500 km
2 and 10 000 km
2 – (4% of all
rivers), and
• 8 rivers with catchment area larger than 10,000 km
2 – (0.4% of all rivers) [3].
P. Jokiel and P. Tomalski
the seasonality of the Vistula flows became considerably higher than of the Oder, and
the differences were the most pronounced in the 1960s and 1970s. In recent years,
their significance has been declining.
Keywords Flow seasonality · Multiannual changes · Spatial diversity · Big Polish
rivers
10.1 Introduction
The catchment area of the Baltic Sea drains 99.7% of Poland’s territory. Polish
borders are largely hydrographic boundaries, as the country comprises nearly 87%
of the Vistula basin and over 89% of the Oder basin. These are favorable conditions
for rational water management, as the vast majority of Polish water resources origin
within the same country. The basins of the Vistula, the Oder, rivers of the Baltic
Sea coast and the catchments of the Vistula Lagoon and the Szczecin Lagoon drain
nearly 98.9% of Poland’s area. Only 1.1% of the country territory is found within the
catchments of the Niemen (the ´
Swisłocz, the Czarna Ha´ ncza, the Szeszupa rivers),
the Dniester (the Strwi˛ a˙ z river), the Danube (the Czarna Orawa and the Metuje
river) and the Łaba (the Izera river). The springs of two out of four largest Polish
rivers are located outside Poland, i.e. the Oder in the Czech Republic and the Bug
in the Republic of Ukraine. This is one of the reasons why total river flow from
Poland is formed within the area by 12.3% larger than the country’s area and covers
351,028 km
2 . At the same time, only 87% of the country’s river water resources
originate from the territory of Poland.
The Quaternary evolution of the Polish river network resulted in a considerable
asymmetry of left and right basins of major Polish rivers (the Vistula: 72.8% ÷ 27.2%;
the Oder: 70.5% ÷ 29.5%). The same processes caused the main right tributaries of
the Vistula and the Oder (the Narew with the Bug and the Warta) to be longer and have
larger or slightly smaller basins than the main rivers. Another characteristic feature
of the Polish river network, particularly within the Polish Lowlands, are relatively
low drainage divides running across wide ice marginal valleys. One of these is the
main drainage divide separating two largest basins of the Vistula and the Oder.
Due to human pressure and local corrections of the river network, the number
of Polish rivers is difficult to estimate and varies over time. According to IMGW, it
amounts to 4,656 including:
• 2,913 watercourses with catchment area smaller than 50 km
2 – (62.6% of all
rivers),
• 1,553 watercourses with catchment area between 50 km
2 and 500 km
2 – (33% of
all rivers),
• 182 rivers with catchment area between 500 km
2 and 10 000 km
2 – (4% of all
rivers), and
• 8 rivers with catchment area larger than 10,000 km
2 – (0.4% of all rivers) [3].