History and background of the Welney Washes

The movement of water in the rivers, and along the Washes, is governed by several main control structures. These are operated by the Environment Agency: 

• Hermitage Lock at Earith, diverts the normal flow of the Bedford Ouse into the Hundred Foot River. This allows a small flow to continue along what is now called the Old West River. The lock also allows navigation between the three rivers.
• Earith Sluice, allows excess floodwaters which the Hundred Foot and Old West Rivers cannot hold to enter the Old Bedford. This then overflows onto/ into the Washes.
• Welmore Lake Sluice is 19 miles north-east of Earith. It is where the retained floodwaters are released into the New Bedford River when tides and the river level are low enough.
• The Old Bedford Sluice/Lock near Salter's Lode is 21 miles from Earith. It allows navigation and two-way water flow. Excess fluvial water can exit into the Tidal River. In summer, water from the Tidal River can be taken into the Old Bedford for irrigation purposes. 
• Welches Dam Pumping Station and Welney Sluice Gate are six miles apart but operated with each other. At Welches Dam, the two rivers on the west change their name and their function.

Many of the operations are automatic. They are based on the waters levels monitored and recorded by telemetry. Some of these parameters are set by law.