Influence of Precipitation on Osa River Discharge in 1966-2015 Period

• Main Author: Katarzyna KUBIAK-WÓJCICKA
• Format: Article
• Language: English
• Published: Cluj University Press 2020-03-01
• Series: Aerul şi Apa: Componente ale Mediului
• Subjects: precipitation; discharge; meteorological drought; spi; river osa; poland
• Online Access: http://aerapa.conference.ubbcluj.ro/2020/PDF/2_KUBIAK_11_22.pdf

The aim of the study was to determine the impact of precipitation on the volume of river discharge on a multiannual and seasonal basis. The research area covered the Osa River agricultural catchment located in northern Poland. For the purposes of the analysis, there were used the data from the Institute of Meteorology and Water Management - National Research Institute, covering average monthly sums of precipitation at the meteorological station in Radzyń Chełmiński and average monthly flows of the Osa River in the gauging station Rogóźno in 1966-2015. For the identification of dry and wet periods, the Standardized Precipitation Index (SPI) was used in various accumulation periods, i.e. 1, 3, 6, 9 and 12 months. In the years 1966-2015, the number of dry months (SPI ≤ -1.0) prevailed over wet months (SPI ³1.0). Depending on the length of the precipitation accumulation period (1, 3, 6, 9 or 12 months), there were identified between 89 and 138 dry months, which constituted from 14.8% to 23% of all months in the analyzed multi-year period, respectively. Wet months accounted for 81 (13.5%) to 100 (16.7%) months. Relationship between SPI values in different periods of accumulation and average discharge (SQ) of Osa River was presented in the form of a correlation coefficient r. The highest correlation coefficient between SPI and SQ was obtained between precipitation in accumulation period of 6 months and average monthly discharge (r = 0.72). The indicators can be used for a drought early warning system, which is of particular importance for agricultural areas.