Biocenotic reserve, created in 1998, located in the Zagórki forest district with a total area of 203.05 hectares. It was created by damming water on the stream Duży Pioter.
Rare plants found in the reserve include: marsh Labrador tea (Ledum palustre), lily of the valley (Convalaria majalis), spider plant (Anthericum ramusom), common bladderwort (Utrcularia vulgaris) and water buttercup (Ranunculus lingua). Aquatic vegetation has formed a community of water knotweed and rigid hornwort. The highest natural values focus in the lake, which is one of the most valuable refuge of wetland birds throughout the Lublin region. Visitors can see the bittern, white-tailed eagle, lesser spotted eagle, little crake, white-winged tern. It is also a place for hatches of cranes and greylag geese and in the nearby alder – of eagle owl. The population of black-necked grebe is the largest in the whole Lublin region and one of the largest in the country.