in this part of this act—
“the bridge” means the bridge of the board at gainsborough, partly in the parish of bole, district of bassetlaw, nottinghamshire, and partly in the district of west lindsey, lincolnshire, which carries the railways linking doncaster and retford with gainsborough over the river;
“the level of high water” means the level of mean high-water springs;
“the new span” means a new bridge span positioned on the existing piers of the bridge;
“the river” means the river trent; and
“the specified works” means the removal by the board of the existing span of the bridge and the positioning of the new span under their existing powers.