"Źródła Tanwi" is a peatbog and forest reserve with the area of 186.54 hectares situated in Narol commune. It encompasses peatbogs and swamp woods.
The reserve was set up to protect the natural peatbog as well as surrounding pine and swampy forest situated in the headwater area of the Tanew river. There are found here numerous protected species of flora and fauna (glacial, subarctic and Atlantic relics).