Time and space diversity of the specific discharge in the Zgłowiączka river basin (eastern part of Kujawy)

The article presents the results of analyses and research into the magnitude and long-term course variability, as well as spatial distribution of water resources (expressed as the mean annual specific discharge) within an agricultural area which is particularly threatened by water deficit. The long-term analyses relied on the data retrieved from the monitoring network of the Institute of Meteorology and Water Management (IMGW) for the period 1951-2012. The spatial distribution of water resources was depicted on the basis of the data obtained from own observation facilities. The hydrological image of the river basin concerns two extremes: the years which were either anomalously wet or dry. The average long-term (1951-2012) specific discharge from the Zgłowiączka river basin stood at 2.51 dm3·s-1·km2. On the basis of the direction of the moving trend line of the mean annual specific discharge, three characteristic periods have been identified: 1951-1980 – the increasing trend, 1981-1991 – the decreasing trend and 1992-2011 – the increasing trend. In the anomalously wet year (2011) the mean annual specific discharge from the Zgłowiączka river basin was estimated at 5.80 dm3·s-1·km-2. Incidentally, the discharge level noted in 2011 was the second largest for the studied period (1951-2012). Only in 1980 it was higher standing at 6.79 dm3·s-1·km-2. The discharge in the dry year (2012) was 1.30 dm3·s-1·km-2. The anomalously high specific discharges in 2011 were ascribed to the hydro-meteorological conditions prevailing in the studied period