Summary:

The paper deals with the characteristics of surface and ground water che-mistry in meliorated bottom of river Ochoża valley. Meliorated green lands cover 20% of the whole catchment and are localized on organic soils in Tyśmienica river valley counted in part to Nature 2000 area. Analysis of physicochemical properties of waters aim at evaluating the effects of anthropogenic transformations and learning the factors that exert their influence on water quality over the studied area. Water samples were collected at different seasons of 2004-2006 at several measurement points distributed within the studied object. Along with water sam-pling, periodical measurements of ground and surface water states, as well as flow rates, were made. Valorization of the soil cover, ways of soil performance, and plant coverage was also performed within the frames of previous examinations. The hydrological measurements revealed that the highest water states were most often in March. Along with the time, water flow rate decreased reaching the lowest values in August. The water quality indicators on studied area oscillated within quite wide range. Surface waters, stagnating in ditches were characterized by the poorest quality in July on blueberry plantation.