| Abstract [eng] |
Summary. The aim of this work is to evaluate the tendencies and reasons of the quality changes of the water of Merkio river-basin during 1992-2008. On purpose to evaluate the condition of existing pieces of water it is necessary to make permanent observations of surface pieces of water. The main parameter of the management of water quality becomes biological parameters which are influenced by equally important hydrochemical water parameters. In the surface evaluation of water quality biological parameters play an important role, more precisely the species which react directly to the water pollution. The subject of research is hydro morphologic, some common – chemical monitoring data of 4 places of Merkio river-basin: down Dubininkai, higher up Varena, down Salcininai and down Puvociai during 1992 – 2008. Until 2005 these points – the places of sample taking were the permanent measuring points. Since 2005 the number of monitoring places has increased; observation points have spread all over the basin of the river Merkys. The data of 1992 – 2008 have been received from Environment protection Agency, River-basin management department. Evaluating the current water quality in these places there were selected the main parameters that could visually reflect the changes of water quality. During the analysis of the water quality of the river Merkys the data of study parameters were chosen in accordance with yearly seasonality. Al physical chemical parameters were measured and fixed every year, 12 times per year, throughout every month. According to the change of these parameters there were chosen 4 months: January, April, July and October. It should be noted that study parameters vary throughout the year and have certain rises, peaks and deviations. Comparing the reports of some years in which water quality established according to biological parameters is very good or good, the river under investigation belongs to very clean or clean water – I - II quality classes. In accordance with examined water quality parameters water quality of the river Merkys is improving, water condition remains stable and does not require additional environment protection means. Keywords: the basin of the river Merkys, water quality, hydro morphologic and common – chemical parameters. |
