The 20th century saw two major phases of improvement. In 1905, the New Junction Canal connected the Aire and Calder to the Sheffield and South Yorkshire Navigation near Stainforth. It was funded by the Aire and Calder, with the Don Navigation eventually meeting half the cost. During the 1960s, the navigation underwent another modernisation scheme, in which the locks from Goole to Leeds were upgraded and enlarged to accommodate vessels conforming to the 600-tonne Euro-barge standard. There is some variation in lock sizes, with the smallest being at Knostrop, which is with a water depth of over the lock cill. Euro barges are , and when fully loaded with 600 tonnes of cargo, have a draught of . Locks on the Wakefield section can accommodate vessels which are with a draught of , though rigid vessels are constrained to 141 ft to enable turning at Wakefield while the locks below Castleford have three sets of gates, so that a section can be used, rather than the full required by the compartment boats.