Divers are checking the supporting stanchions of the old White Bridge in Hartsholme Country Park in Lincoln before the new replacement bridge will be put in place.
Specialist divers will build a small dam around the supporting stanchions in the lake. This will allow final checks to confirm their stability to take place.
The bridge itself is currently being fabricated off site by Lincoln-based firm John Martin Hoyes Ltd.
If divers confirm the supporting stanchions are safe, the firm will be able to fit the new structure over the coming weeks.
Alan Brookfield, Project Manager at the City of Lincoln Council, said: “This is the final piece of work to be done before the arrival of the new bridge.
“The stanchions are the original ones which held up the old bridge for over a century and their capacity to hold the new bridge was assessed last year.
“We are now making final checks to ensure there has been no change in the stanchions and their bases since that assessment took place.
“We need to be 100% assured of their ability to hold the new bridge before its arrival.
“The divers will create a ‘coffer dam’, which will give access to the lower parts of the stanchions and allow the structural arrangement and general condition of the stanchions below the water line to be assessed.
“Once we receive the all clear, the new bridge can start being constructed on site.”
The previous bridge was found to be unsafe for public use and was closed in July 2012, with the timber deck and upper steel work being completely removed.
A budget of around £65,050 has been put aside for work on the new bridge, with £35,000 coming from existing corporate property budgets and £30,050 from the council’s capital contingency fund.