The Old Bedford River is an artificial, partial diversion of the waters of the River Great Ouse in the Fens of Cambridgeshire, England. It was named after the fourth Earl of Bedford who contracted with the local Commission of Sewers to drain the Great Level of the Fens beginning in 1630. It provided a steeper and shorter path for the waters of the Great Ouse, and was embanked to prevent them flooding the low ground of the South Fens. Throughout the project, the Earl and his Adventurers faced disruption from those who were opposed to drainage schemes. The project was deemed to have succeeded in draining the fens in 1637, but that decision was reversed in 1638. After a lull during the English Civil War, when much of the work was damaged, the Dutch engineer Cornelius Vermuyden worked with William Russell, the fifth Earl of Bedford to complete the drainage. Disruption and unrest continued while the work was carried out, resulting in the Adventurers employing armed guards. A second river, the New Bedford River, was cut parallel to the first channel, which then became the Old Bedford River. At some point, the Old Bedford River was split into two parts, when the upper section was diverted into the River Delph at Welches Dam, and the lower section was joined to the Counter Drain. Both parts retain the name, but are not connected to each other. The area between the two Bedford rivers acts as a large washland, which holds floodwater when the river channels cannot cope with the volume of water in them.