The engineer Thomas Telford was employed to survey the route, and proposed a canal from Marple on the Peak Forest Canal, which would be level to beyond Macclesfield, and would then descend by a series of locks to the level of the Trent and Mersey Canal summit. It would pass close to Congleton, and would join the Trent and Mersey near Harecastle Tunnel. He stated that an adequate water supply could easily be obtained, and discounted a branch to Stockport, which would have involved a descent of , as the town was already served by the Ashton Canal and the Peak Forest Canal. He considered five possible sites for the location of reservoirs to supply the canal.