The river mouth at Guilderton typically closes during the summer months due to insufficient water flow, creating a sandbar.

[7] The river is prone to periodic flooding unusually following cyclones and tropical depressions crossing the coast further north.

In 1907, the railway lines between Watheroo and Moora were closed for some time when parts of the track were washed away.

[8] More floods occurred in 1917 when 1.7 inches (43 mm) of rain fell in three hours at Mogumber with similar falls in surrounding areas.

Railway lines were undermined to a depth of 30 feet (9 m) leaving Moora isolated from Perth by both road and rail.