The Rinza River is the only river in the Kocevje region beside the bordering Kolpa river. It is clearly a karst river. The Rinza River has many springs and the biggest one near the village of Mrtvice is called Reberski studenec. After a short flow on the surface it disappears underground at the end of the Kocevje Plains. In the old times the river flowing through Kocevje represented a defence ditch surrounding the castle with the town centre, creating an island. After the threads of invasion were over the ditch was filled up and nowadays the Rinza River forms a bend around the old town centre. The river was kept on surface with the help of dams. In the period of industrialisation there were many sawmills and mills operating along it. Today is polluted as the town's sewer system still partially flows into it.

Conflucence of Sava and Krka is situated between the village Catez ob Savi and the city Brezice. Bridge is a popular point for photographers and lovers of the nature. The Brezice valley with the rivers and affluents belongs between the most important hydrographic region in Slovenia. Rivers played an important rule in the life of the inhabitants. The only source of the income was for many families trading with fishes. By rivers they built knittings of drawing ropes, harbours and shipyards. At the same time they started to built rests and restaurants for rafters. River was the only traffic road for rafting trade until it was buit the first railway line.