The changes of surface and ground water level on the effect of regulated outflow

This paper aims to analyze the variability of the levels of surface and ground water in the Ochożanka basin. The depth at which the ground water table occurred was studied with reference to the adopted land drainage standards. The studies were carried out in 2009/2010–2014/2015 for natural and regulated water outflows. The analysis of annual total precipitation in the analyzed period some years were very wet (2009/2010 and 2013/2014), some of them were wet (2010/2011, 2012/2013), one year was dry (2014/2015) and one year was normal (2011/2012). The six-year average seasonal precipitation amounted to 593 mm, which was 66 mm higher than average precipitation recorded in 30 years. Under regulated outflow conditions the level of water in the river ranged from 55 to 77 cm. The level of water under natural outflow ranged from 18 to 49 cm. In the area with regulated outflow the average ground water level was 47 cm. In the remaining area of drainage system ground water level was 67 cm. Also, the dynamics of variance in the water level under natural outflow conditions was clearly higher.