On the route of the waters of the Krka River to its mouth, they first must cross Bilušića buk, 16 km from the source of the river.
This noisy and picturesque waterfall is 22.4 m high, 300 m long, and around 100 m wide. The river flows over it all year round in its full power. The waterfall abounds in tufa forms such as ridges and overhangs. Downstream from it, low barriers are located, and below them, where the river broadens and calms, there are tufa islets and sills. It is surrounded by lush sub-Mediterranean vegetation and dense willows, while the rocks of the waterfall are inhabited by rich mossy vegetation with the species Cratoneuron filicinum and Fontinalis antipyretica, and, more rarely, a subspecies of the liverwort Marchantia polymorpha (subsp. montivagans), otherwise present in elevated and mountainous habitats.
The area of Bilušića buk also contains watermills, fuller mills, and washing posts. There are also several speleological structures, the most important being Sedrena špilja cave behind the mill, 124 m long.
