The object of study is to analyze the size of the components of the water balance in irrigated river valleys micro-catchments of diverse habitats. The study used the results of research and field observations from the years 2010–2012. Carried out investigations of two small lowland catchments indicate significant impact of meteorological conditions as well as habitats on runoff index, retention changes in analyzed hydrological years. Catchment ditch K-2 is located in Piwonia river basin, and ditch the Z-6 is located in Bystrzyca river basin. The highest rates occurred in the first half of the outflow year 2009/10, and have been associated with heavy rainfall. They were almost three times higher than in an average year 2011/12. This balance is particularly true of the flatness of the terrain impedes drainage and reduced absorbency that especially during the spring excesses can not store large amounts of water. The catchment ditch Z-6 observed changes in retention were significantly higher than in the catchment ditch K-2, due to the different soil cover and other land uses. Studies have confirmed the dominant role of surface evaporation in the water balance. This is evidenced by the lower outflows in the first half year compared to the first half of the winter and fall in retention.

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