River Little Ouse - Flood Precautions

Flood Precautions

The Environment Agency has designated the section from Thetford to Brandon, where it flows through the afforested Breckland, as a Flood Warning Area.

The lower part of the river crosses over the Cut-off Channel in a concrete aqueduct. The Channel is a 25-mile (40 km) drain which runs from Barton Mills to Denver along the south-eastern edge of the Fens, and was constructed in the 1950s and 1960s. During times of flood it carries the head waters of the River Lark, the River Wissey and the Little Ouse to Denver Sluice. On its south side are two sluices, so that flood water from the upper river can be diverted into the cut-off channel and the section between there and the Great Ouse isolated. The flood banks on this lower section are up to half a mile wide so that the meandering river will form a large lake.

Nearer the mouth of the river, the Brandon Engine was the main outlet for the drainage of the northern half of Burnt Fen from 1830 until 1958. The original steam engine was replaced in 1892, by a new engine that could pump 75 tons per minute. That engine was replaced by a 250 horse power oil engine in late 1925, supplied by Blackstone and Company, which drove a 42-inch (110 cm) Gwynne rotary pump. The pump could discharge 150 tons per minute against a head of 18 feet (5.5 m), and lasted for 30 years. When a replacement was considered in the 1950s, the Commissioners of the Burnt Fen were faced with the problem that the White House Drain which supplied it had become bigger and more unstable as the ground surface had shrunk, and the engine sat at the top of a hill, rather than at the lowest point on the northern Fen. Consequently, a new electric pumping station was constructed at Whitehall on the River Great Ouse, the flow in the drain reversed, and the pumping station decommissioned.