In 1789 Robert Whitworth developed fresh proposals to vary the line of the remaining part of the canal, including a tunnel at Foulridge, lowering the proposed summit level by , using a more southerly route in Lancashire. These proposals were authorised by a fresh Act in 1790, together with further fund-raising, and in 1791, construction of the canal finally recommenced south-westward from Gargrave, heading toward Barrowford in Lancashire. By this time planning for the competing Rochdale Canal was under way and it was likely to offer a more direct journey to Liverpool via Manchester and the Bridgewater Canal. The same year John Rennie surveyed a branch of the Rochdale between Todmorden and Burnley.