The Blyth Navigation was a canal in Suffolk, England, running from Halesworth to the North Sea at Southwold. It opened in 1761, and was insolvent by 1884. Its demise was accelerated by an attempt to reclaim saltings at Blythburgh, which resulted in the estuary silting up. It was used sporadically until 1911, and was not formally abandoned until 1934. History Between Southwold and Walberswick, the mouth of the River Blyth forms a tidal creek, which opens out into a large area of saltings below the first bridge over the river at Blythburgh. The river was navigable to the port of Blythburgh until the 16th century, but navigation was increasingly affected by silting up of the channel. The volume of water which drained from the saltings on every tide kept the mouth of the river scoured, and enabled Southwold to develop as an important, though minor, port. The idea of making the river navigable beyond Blythburgh was proposed by Thomas Knights in the 1740s. Knights was a brewer from Halesworth, and suggested that Southwold harbour needed to be improved first. An Act of Parliament was obtained in 1746 to authorise the improvements, which were sufficiently successful that harbour dues more than doubled over the next five years. Knights tried to gain more support for a navigation to Halesworth, and a plan for the navigation, including a branch from Halesworth to Ubbeston was prepared by Benjamin Reeve in 1753. The project which included three locks was costed at £4,614 by John Reynolds in May 1753, but there was a delay before the bill was submitted to Parliament. Following the granting of an Act of Parliament on 1 April 1757, which included additional powers for the Southwold Harbour trustees, a new survey was carried out by Langley Edwards, who estimated the cost at £3,000, which included the purchase of Wenhaston watermill. By 1759, subscriptions had been received from 38 people, mainly from the immediate locality, for a total of £3,600. Having made the estimate, Edwards was responsible for completing the work to that price, but failed to attend most of the meetings which the commissioners called. Despite his elusiveness, the work was completed at a cost of £3,822, and the official opening took place on 23 July 1761. Operation As built, the navigation had four locks and a tidal staunch located just above Blythburgh bridge. From the sea, it followed the River Blyth