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.
As the river moves through the confined valley carved from soft shale of Jurassic rocks, it can lead to sudden flooding like those experienced in 1840, 1930, and 2000 due to heavy rainfall.