Mountain landscape is not suitable for peatland development. Peat bogs originated in mountains area are characterised by small area and thin layer of organic matter therefore any artificial influence may strongly disturb the structure of a water cycle in a whole peatland basin. Wielkie Torfowisko Batorowskie is a peatland situated at the southwest part of Poland in Stołowe Mountains, which are mainly built of marls and sandstones. The peatland area covers 35ha and its catchment is 120ha when the maximum depth of the peat is 510 cm. Approximately one hundre years ago the bog was afforested by Norway spruce (Picea abies). Another artificial influence was to cross the peatland and its catchment by ditches. These caused the increased of surface runoff and lowering of groundwater table on the peatland, especially on its margin parts when peat soil became strongly mineralized and the process of the peat formation was stopped. Only a few hectares in the centre of the bog kept its natural character. The influence of the artificial drainage on the water cycle mainly concerns the stream outflow from the bog which is increased by ditches, especially during winter time. Wielkie Torfowisko Batorowskie lost some character as a reservoir of water storage contributing the water stocking in the catchment area.