The river flows through the narrow valley that the water has cut into the soft shale of the Jurassic rocks. Because of this, the rainfall can cause rapid flooding like those suffered in 1840, 1930 and in 2000.
Flowing through the confined valley formed by Jurassic rock layers eroded by water, the river experiences sudden flooding akin to events of 1840, 1930, and 2000 due to heavy rainfall.