The variability of flow in two small lowland watercourses was studied in hydrological years differing in the pattern of meteorological conditions. It was found that the rate of water flow was lower in summer half-years than in winter halves. In some periods of the former, the flow disappeared. Such periods were longer for a smaller, 100% afforested catchment. There were significant differences in unit discharges to the advantage of the larger catchment with a twice lower forest cover index. Those might be attributed to the three times higher proportion of boggy sites in the forest area of this catchment.

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