Wallasey Pool

Wallasey Pool was a natural tidal inlet of water that separated the towns of Wallasey and Birkenhead on the Wirral Peninsula, England. Originally flowing directly into the River Mersey, it was converted into the sophisticated Birkenhead Dock system from the 1820s onwards by land reclamation, with the main portion of the pool becoming known as the Great Float. In 1933, with the exception of a small lake, the head of Wallasey Pool at Poulton was converted into Bidston Dock. By 2003, this dock had been filled in.

A new development was approved for Birkenhead docks in 2010. The Wirral Waters development will transform the docklands area into business, leisure and retail facilities.

Four road bridges cross the former Wallasey Pool, over what is now Birkenhead Docks:

Egerton Bridge is situated between Egerton Dock and Morpeth Dock and is a bascule bridge. It was built between 1928 and 1931, replacing an earlier hydraulic swing bridge. The bridge and the machine house were completely restored in 1993 and opened to the public in 1995.

A red girdered bascule bridge at Tower Road connects the Seacombe district of Wallasey with Birkenhead. Known as the Four Bridges, as originally four movable bridges existed along Tower Road: two between the Great Float and Alfred Dock, one between the Great Float and Wallasey Dock and one between the Great Float and Egerton Dock. When originally built, all four were hydraulic swing bridge types. In the 1930s most were replaced by bascule bridges.

...
Wikipedia