Below: The south end Docks. Over half the water spaces are gone - outlined in red.
Below: Central Docks. About a third are gone with three docks to the right reduced to canal boat depths only. No deep water ships can berth there anymore. Only the docks to the left of picture can accomodate deep water vessels: Bramley Moor, Nelson, Salisbury (a small transit dock), Collingwood, Stanley and Clarence Graving Docks. From the outleined infilled docks to the Liver Buildings, to the right, no large vessels can berth anymore.
My ballpark estimation, without all the data, is that Liverpool and the Wirral so far have lost more water space that what there is in Venice.