City officials on both sides of the river say they have contingency plans in place to meet the need for drinking water if a treatment plant is forced to shut down during the flood.Water treatment plants in both Ottawa and Gatineau are behind sandbags in order to protect them from the Ottawa River, now nearing its initial peak. Officials said Monday that all of the facilities are operating normally.“We need to make it clear that the city’s drinking water is absolutely safe,” the city’s head of emergency management, Pierre Poirier, told reporters Monday. “There is currently no operational threat to any of the city’s water facilities.”On Saturday, members of the Canadian Armed Forces built a sandbag wall to protect the access road, Cassells Street, that leads to the Britannia Water Purification Plant. Cassells Street is used to transport water treatment chemicals to and from the plant, built in 1961.It produces about half of the 275 million litres of drinking water used in Ottawa each day.City manager Steve Kanellakos has warned that the city doesn’t have room to stockpile water treatment chemicals at the plant, which could imperil its operations if the road is impassable for weeks at a time.Bay ward Coun. Theresa Kavanagh said Monday that the access road to the Britannia plant is now well protected on both sides by sandbags. City officials have briefed her on the situation, she said, and “they’re satisfied it will work.”“We’re preparing for the worst case scenario: We can’t leave anything to chance when it comes to our drinking water,” Kavanagh said.The city’s other major water purification plant on Lemieux Island has the capacity to supply all of the city’s drinking water needs, she said, in the event of an emergency. The Lemieux Island plant can produce up to 400 million litres of drinking water each day.(By law, all councillors must be briefed on the city’s water supply; it was one of the recommendations made by the inquiry into the E. coli contamination of Walkerton’s drinking water in 2000.)Poirier said that “out of an abundance of caution,” the city has also asked troops to sandbag the road leading to the Lemieux Island plant to ensure access to it as the flood peaks.In Gatineau, city spokeswoman Bianca Paquette said dikes have been built around the wastewater treatment plant in Gatineau, and the water purification plant in Aylmer.Both facilities, she said, remain in operation despite the rising water levels. In addition, water pumps have been installed and can be deployed if floodwater begins to threaten one of the facilities.What’s more, Paquette added, since Gatineau has four drinking water production plants, contingency plans have been developed to meet the city’s needs.All critical infrastructure on or near the river is being carefully monitored.The federal department responsible for the Chaudière Bridge — it’s officially known as the Union Bridge on the Chaudière Crossing — ordered it closed starting at 6 a.m. Sunday because of high water levels and flows on the Ottawa River.It’s not clear how long the bridge, a key transportation link between Ottawa and Gatineau, will remain closed to traffic.Spokeswoman Michèle LaRose said the bridge must be inspected for damage before it can reopen, and the water must recede enough for that to happen.Pictures taken by a Postmedia photographer Monday show damage to a decommissioned steam pipe on the underside of Union Bridge. PSPC will re-evaluate the damage once water levels have gone down. It does not affect the integrity of the bridge.Carleton University structural engineering professor David Lau, director of the Ottawa-Carleton Bridge Research Institute, said floods like the one on the Ottawa River can “seriously impact” a bridge.Floodwaters can scour a bridge’s foundations, and exert stress on its structures, he said. “Depending on the level of the water, if it reaches the deck level of a bridge, it also creates buoyancy,” he added.Buoyancy is a force that few bridges are engineered against. “It’s very rare, but these extreme events seem to occur more frequently,” Lau said.