River_Stour,_Suffolk

The River Stour (, pronounced rhyming with either "tour" or "sour") is a major river in East Anglia, England. It is 47 miles (76 km) long and forms most of the county boundary between Suffolk to the north, and Essex to the south. It rises in eastern Cambridgeshire, passes to the east of Haverhill, through Cavendish, Sudbury, Bures, Nayland, Stratford St Mary and Dedham. It becomes tidal just before Manningtree in Essex and joins the North Sea at Harwich.
The origins of its name are unclear, but several possibilities have been proposed by scholars. The entire non-tidal river above Manningtree is designated as the Dedham Vale National Landscape, formerly known as an Area of Outstanding Natural Beauty. It has been painted by a number of prominent artists, including John Constable and Thomas Gainsborough.
The river was improved for navigation following the passing of an Act of Parliament in 1705. Locks were built to enable lighters to reach the town of Sudbury. Most of the locks were associated with mills, and the original 13 flash locks and 13 pound locks were replaced by 15 pound locks in the 19th century. The river was reasonably profitable at the beginning of the 19th century, but the advent of the railways led to a steady decline from 1852 onwards. Attempts to abandon it were thwarted by legal difficulties, but in 1914 the River Stour Navigation Company declared itself bankrupt, and the river soon became moribund.
From 1928 onwards, the river became a major source of drinking water, with South East Essex Waterworks (now Essex and Suffolk Water) extracting water at Langham and then Stratford St Mary pumping stations. As the demand for water grew, the Ely-Ouse to Essex Transfer Scheme was implemented, with water from the River Great Ouse discharged into the upper reaches of the river, and extracted again by the pumping stations. A third extraction point was added near Brantham, so that volumes of water flowing through Flatford could be maintained at a higher level for the benefit of tourists. To prevent salt water entering the river valley, sluices and a barrage were built at Cattawade, preventing boats from entering the river from the estuary.
The River Stour Trust was set up in 1968 to campaign for greater use of the river for navigation. It has worked to refurbish four locks, and to run boat trips from Flatford and Sudbury. The river can be used by unpowered craft between Sudbury and Cattawade, but powered boats are normally only allowed between Sudbury and Henny Mill, although the Trust has permission to run an electric boat at Flatford. Canoes and kayaks have to be portaged around the former locks where these have been replaced by fixed weirs and sluices.