Boat traffic on the Mississippi River is at a standstill for the winter, allowing for major renovations at Bellevue’s Lock and Dam. It’s the first-ever overhaul of Lock and Dam Number 12, which has been the portal for all watercraft on that leg of the Muddy Miss for more than 60 years. Lockmaster Leonard Ernst says decades of bumping barges have taken a toll on the concrete walls.Ernst says the upper 20 feet of the 32-foot-deep chamber is being rebuilt with reinforced armor set in concrete. The Lock and Dam is also getting a new electrical system and new machinery to operate the locks. Ernst says crews pumped 12-million gallons of river water out of the lock chamber before the work on the walls could begin.Once all the water was pumped out of the chamber, Ernst says all sorts of junk was found at the bottom, including all sorts of old boat parts and several truckloads of zebra mussels. The project is expected to cost 16-and-a-half million dollars and should be done by early March.