In 1963, during construction of a coffer dam, state officials removed the rock from the river for preservation.

In the first phase a leak-proof coffer dam was constructed to isolate and dry the work area.

At the end of the project the coffer dam was removed and the fill loaded onto barges for removal.

The construction of a coffer dam enabled land reclamation and excavations to take place.

First, the power house was constructed after a circular coffer dam was set on the right side of the river.

Nyaminyami had struck again, destroying the coffer dam, the access bridge and parts of the main wall.

Matthew looked across at the door that led to the coffer dams and then back out into the room.

Work began in 1824 and the foundation stone was laid, in the southern coffer dam, on 15 June 1825.

The company built several coffer dams, all of which were destroyed when the river flooded in 1914.

Work commenced on a protective coffer dam until 1940, with total costs of construction coming to £70,000 (equivalent to £2.5m today).