The River Churn starts at Seven Springs and flows down the valley into Cirencester and then via Siddington and South Cerney where it joins the River Thames. The Daglingworth stream starts around Duntisbourne Abbots and flows through Stratton and across the water meadows to Barton Mill House, and eventually reappearing in the Abbey Grounds (where it is mysteriously renamed The Churn).
When the Romans built Corinium they diverted the two rivers around the fortified walls.
In the 15th Century a number of water-powered mills were built (Stratton, Barton, Abbey, New, Preston and Siddington) and the owners needed a reliable source of water and as a result a series of artificial channels and mill ponds were built. Barton Mill was built on the route of the Daglingworth Stream and later, some of the Churn was diverted to the Mill to provide more power. Then it was decided to extend this as the Gumstool Brook and along the south of Coxwell Street to feed the Abbey Mill where Gosditch Street and Dollar Street meet. This stream became a grossly polluted sewer and the source of diseases and so was culverted. However, when more of the Churn was diverted to power the Abbey Mill it caused flooding in Coxwell Street. To reduce this, the stream between the Mead and Powell’s School was cut to flow under Spitalgate Lane and into the Abbey Lake.
In the late 18th century when a branch of the Severn-Thames canal was built to serve the town another canal feeder was created by diverting the Daglingworth Stream across the Bathurst Estate under Cecily Hill to the wharf in Sheep Street. Now, near the course of the Churn, some houses built in 1968 have sewers where groundwater is likely to be a significant source of escape of untreated or partially treated sewage. So it appears that some residents are still suffering from the same problems that were experienced so many years ago.
The geology of the flood plain on which Cirencester sits between its two rivers means that the water table can sometimes achieve high levels. Several groups are attempting to work with the County, District and Town Councils plus Thames Water and the Environment Agency to find ways to improve the situation following the dreadful events over last Christmas and New Year.
Cirencester Civic Society https://www.ccsoc.org.uk/