It is generally believed that the spoils from construction of the Mersey road tunnel, were used to create Otterspool Promenade. The facts are only slightly different.

The excavation of the Mersey road tunnel produced vast quantities of rock and gravel which had to be taken from the workings. The solution to the problem was resolved when it was realized that a river wall was being constructed as a preliminary to the building of Otterspool Promenade some four miles from the tunnel. About one mile nearer, land reclamation was being undertaken at the Liverpool district of Dingle. All spoils were divided between these two sites.

In 1982 the Festival Gardens were opened. Amongst other things the Gardens resulted in the completion of the river wall between the two sites. The river wall including Otterspool Promenade now forms a small part of the Mersey Way, a footpath which runs through to Hull on the other side of the country.