Figure 1
Location of Ner catchment area, showing Dabie (Dąbie) water gauge and the city of Lodz (Łódź)
Source: own elaboration
Figure 2
Days of river ice phenomena (light blue) and river ice cover (dark blue) on the Ner river at Dabie water gauge, 1951–2017
Source: own elaboration (developed using data from IMWM-NRI)
Figure 3
Annual water usage in Lodz city agglomeration (Vu) and its cumulated quantity (Vucum), 1951–2017
Source: own elaboration (developed using archival materials of the City of Lodz Office, Statistical Yearbooks of the City of Lodz, CSO Local Data Bank, and Environmental Protection and Water Management Reports)
Figure 4
Variability of start (dSIP – A) and end (dEIP – B) dates of ice phenomena occurrence, as well as start (dSIC – C) and end (dEIC – D) dates of ice cover appearance on the Ner river at Dabie water gauge, 1951–2017. Red lines show trends. Trend equations given in boxes; R2 – coefficients of determination; [year no.] – consecutive number of year from beginning of data series (1951 is no. 1); α – significance level of trend equations; Mann–Kendall test was used.
Source: own elaboration
Figure 5
Variability of duration of ice phenomena (DIP – A) and ice cover (DIC – B) on the Ner river at Dabie water gauge, 1951–2017. Red lines show trends. Trend equations given in boxes; R2 – coefficients of determination; [year no.] – consecutive number of year from beginning of data series (1951 is no. 1); α – significance level of trend equations; Mann–Kendall test was used.
Source: own elaboration
Figure 6
Correlation between duration of ice phenomena on the Ner river (DIP) and annual mean water temperature (Mtw) in particular years within 1965–2014
R2 – coefficient of determination
Source: Jokiel & Bartnik 2020
Figure 7
Double-mass curves of cumulated duration of ice phenomena (DIPcum) and cumulated duration of ice cover (DICcum) on the Ner river at Dabie water gauge versus cumulated volume of water uptake by Lodz city agglomeration (Vucum), 1951–2017. Red lines are aligned cumulations; arrows indicate years of significant disruption of homogeneity.
Source: own elaboration