Nauka Przyroda Technologie

2014 volume 8 issue 4 #46

Arkadiusz Bartczak, Ryszard Glazik, Sebastian Tyszkowski

Identification and evaluation of the intensity of dry periods in eastern part of Kujawy

Summary.

The main objective of the article was the identification of atmospheric droughts and river low flows and the evaluation of their intensity in Eastern Kujawy region in Poland. The atmospheric drought evaluation process was performed with the use of the Standardised Precipitation Index (SPI). A properly classified value of the index informs not only about a drought event occurring, but also about its intensity in three categories: a moderate drought, severe drought and extreme drought. The analyses were carried out on the basis of the data received from five precipitation stations: Izbica Kujawska, Chodecz, Duninów, Baruchowo and Gostynin. The river low flows were described with the following parameters: duration, mean discharge, minimal discharge and the volume of water shortage during the low flow. The low flow periods were evaluated for the following rivers: Zgłowiączka, Noteć Górna and Tążyna. The analyses encompassed the period 1951-2010. Meteorological droughts of various intensity occurred with the frequency of 30% (from 29% in Duninów to 34% in Chodecz). Three characteristic periods in which atmo­spheric droughts of various intensity and long-term and deep low flows occurred were identified for the investigated area: 1) 1951-1959, 2) 1982-1994, 3) 2001-2008. The river low flows were associated with fluctuations, as well as with short-term, statistically significant decreasing trends of precipitation. The most intensive atmospheric and hydrological drought in the investigated period in eastern Kujawy was observed in 1989-1994. The longest low flows (over 200 days) appeared at the time when the discharges of the rivers draining the eastern part of Kujawy were at their lowest. Also the water deficit during this drought event was the highest (5,020,700 m3 in the Zgłowiączka catchment, 2,929,000 m3 in the Noteć Górna catchment, or 3,087,300 m3 in the Tążyna catchment).

Key words: meteorological droughts, low flows, SPI, Box-Cox transformation, moving trend, eastern Kujawy

Full text available in Polish in Adobe Acrobat format:
https://www.npt.up-poznan.net/pub/art_8_46.pdf

Streszczenie w języku polskim:
https://www.npt.up-poznan.net/tom8/zeszyt4/streszczenie-46.html

Corresponding address:
Arkadiusz Bartczak
Arkadiusz Bartczak
Instytut Geografii i Przestrzennego Zagospodarowania im. Stanisława Leszczyckiego Polskiej Akademii Nauk w Toruniu
ul. Kopernika 19
87-100 Toruń
Poland
e-mail: arekbartczak@gazeta.pl

Accepted for print: 18.06.2014