Chapter 10
Flow Seasonality in Two Big Polish
Rivers – The Vistula and the Oder
Paweł Jokiel and Przemysław Tomalski
Abstract The aim of the chapter is to identify the flow seasonality of Vistula river
(14 water gauges) and the Oder river (11 water gauges) located along the river’s
course. For this purpose seasonality index (IS), concentration date (PK) half-flow
date (TPO), and seasonality coefficient (GMO) were used. IMGW-PIB shared hydrometric data for the period from 1951-2016. Average concentration dates and half-flow
dates occurred in April or May in analysed cross-sections. Along Vistula and Oder
rivers mean PK and TPO regress towards winter (are earlier and earlier). Average
seasonality index comprises in the range 20–32%, while seasonality coefficient falls
into the range 9.5–14.5. The highest IS characteristic are for the upper part of the
rivers. Next IS rapidly decreases, due to the summary of the flows from the rivers’
tributaries of which are characterized by various conditions of outflow. A clear correlation was found between the concentration date (PK) and half-flow date (TPO) for
both rivers. These parameters demonstrate a linear trend and PK grows in line with
TPO. However, their regression lines have different inclinations. The rise is slower
for the Vistula but this difference ceases as TPO and PK decrease with a growing
area of both basins. Covariation between average seasonality indices IS and flow
seasonality coefficient GMO is less pronounced in each of the rivers than in the case
of PK and TPO. Multiannual changes in the concentration date (PK) for the Vistula
and the Oder irregularly oscillate around average values, and average PK values for
the upper, middle and lower parts of the catchments are nearly identical. The similarity of PK indices in individual years for the Vistula and the Oder in the analyzed
multi-year period occurred in the lower and middle course of the rivers. For the upper
sections, the differences between rivers are larger, and for the last 30 years there is
a growing tendency for earlier concentration date for the Oder. Changes in the flow
seasonality index IS showed huge variability and depended on the catchment size.
Contrary to PK, relatively the greatest similarities between the Vistula and the Oder
were noticed for their upper sections (R = 0.72). As the catchment area increased,
P. Jokiel (B) · P. Tomalski
Department of Hydrology and Water Management, Faculty of Geographical Sciences, University
of Łód´ z, Narutowicza 88, 90-139 Łód´ z, Poland
e-mail: pawel.jokiel@geo.uni.lodz.pl
P. Tomalski
e-mail: przemyslaw.tomalski@geo.uni.lodz.pl
© Springer Nature Switzerland AG 2021
M. Zeleˇ náková et al. (eds.), Management of Water Resources in Poland, Springer Water,
https://doi.org/10.1007/978-3-030-61965-7_10
181
Flow Seasonality in Two Big Polish
Rivers – The Vistula and the Oder
Paweł Jokiel and Przemysław Tomalski
Abstract The aim of the chapter is to identify the flow seasonality of Vistula river
(14 water gauges) and the Oder river (11 water gauges) located along the river’s
course. For this purpose seasonality index (IS), concentration date (PK) half-flow
date (TPO), and seasonality coefficient (GMO) were used. IMGW-PIB shared hydrometric data for the period from 1951-2016. Average concentration dates and half-flow
dates occurred in April or May in analysed cross-sections. Along Vistula and Oder
rivers mean PK and TPO regress towards winter (are earlier and earlier). Average
seasonality index comprises in the range 20–32%, while seasonality coefficient falls
into the range 9.5–14.5. The highest IS characteristic are for the upper part of the
rivers. Next IS rapidly decreases, due to the summary of the flows from the rivers’
tributaries of which are characterized by various conditions of outflow. A clear correlation was found between the concentration date (PK) and half-flow date (TPO) for
both rivers. These parameters demonstrate a linear trend and PK grows in line with
TPO. However, their regression lines have different inclinations. The rise is slower
for the Vistula but this difference ceases as TPO and PK decrease with a growing
area of both basins. Covariation between average seasonality indices IS and flow
seasonality coefficient GMO is less pronounced in each of the rivers than in the case
of PK and TPO. Multiannual changes in the concentration date (PK) for the Vistula
and the Oder irregularly oscillate around average values, and average PK values for
the upper, middle and lower parts of the catchments are nearly identical. The similarity of PK indices in individual years for the Vistula and the Oder in the analyzed
multi-year period occurred in the lower and middle course of the rivers. For the upper
sections, the differences between rivers are larger, and for the last 30 years there is
a growing tendency for earlier concentration date for the Oder. Changes in the flow
seasonality index IS showed huge variability and depended on the catchment size.
Contrary to PK, relatively the greatest similarities between the Vistula and the Oder
were noticed for their upper sections (R = 0.72). As the catchment area increased,
P. Jokiel (B) · P. Tomalski
Department of Hydrology and Water Management, Faculty of Geographical Sciences, University
of Łód´ z, Narutowicza 88, 90-139 Łód´ z, Poland
e-mail: pawel.jokiel@geo.uni.lodz.pl
P. Tomalski
e-mail: przemyslaw.tomalski@geo.uni.lodz.pl
© Springer Nature Switzerland AG 2021
M. Zeleˇ náková et al. (eds.), Management of Water Resources in Poland, Springer Water,
https://doi.org/10.1007/978-3-030-61965-7_10
181