Some 20km up the Ouse from Naburn weir, a second equally crucial reconstruction operation has just struggled to completion after suffering even more from the river's irascible temperament. Cofferdams protecting the 1M repair of the 225 year old Linton Lock flooded a dozen times leaving contractor Birse Construction little to do for a total 16 weeks of its eventual eight month contract.
Here the river itself initiated the need for substantial lock wall repairs and pressure grouting. Water levels at Linton can rise an incredible 6m in just 24 hours, only to drop again almost as quickly.
Over the years this movement gradually weakened already poor ground conditions around the lock triggering several river bank slips. The largest slip plane passed through the lock itself opening up 150mm cracks in its 2m thick masonry walls and leaving it close to collapse.
But the listed structure - the last surviving example of a design by eminent canal engineer John Smeaton - is not just of historical importance. It is the gateway to the river's upper reaches to Ripon, where BW has invested over 2M in new marinas and repairs to linked canals.
So Linton's lock walls are now relined with traditional lime mortar - more permeable than cement, so reducing stress on the masonry. And the entire structure is protected against further landslips by 170m of sheet piling.
Completion of repairs has an added bonus for BW as it now hopes to gain ownership of the last stretch of the Ouse still in private hands. long time custodian of the lock and 8km of river, Linton Lock Commissioners, is reportedly more than willing to hand over the lot to BW in return for the Board, and a heritage lottery grant, funding most of the repair bill.