Winnipeg is preparing in case zebra mussels arrive at the city's drinking water source.

A million dollars is set to be spent on control measures to prevent zebra mussels from clogging the intake structure at Shoal Lake by 2019.

City officials say it involves the use of chlorine injections to kill the invasive species.

The city says while no zebra mussels have been detected in Shoal Lake, their presence is inevitable.

The project is part of $9 million worth of upgrades at the site over the next five to seven years.