The second largest reservoir in Mazovia was built in 1958–1963. The waters of the Narew River were blocked by a dam in Dębe. The dam is an earth embankment 24 m high. The normal level of damming is less than 7 m, which is enough to create a 33 km² lake in the relatively narrow valley.
The proximity of the capital makes Zegrzyńskie Lake bustling with life from spring to autumn. There is probably no water sport that has not been practiced here.
