It took several hours for the four divers to unfold tarpaulins as barriers over the holes in the embankment so as to prevent the collapse of the wall, the HGSS reported.
The Sava River reached an all-time record high near Jasenovac and at 2 pm on Monday it had risen to a height of 920 centimetres.
The river has flooded some local roads particularly on the Sisak-Popovaca route near Brezovica. The army is building embankments in the most critical spots.
A state of emergency has been declared in the critical spots in the basins of the in the Kosinj valley in Lika and in the valley of the Sava River following heavy snow-melt and rains.
Basements of dozens of houses in those areas have been flooded.