Their installation comes as part of a $10 million program, funded in last year's Council budget, which saw backflow valves placed in stormwater drains around the inner-city .

Backflow valves are attached to the end of stormwater systems, allowing water to exit the pipes but not re-enter.

It stops water from washing back into the drains and out onto local streets and homes.

The two backflow valves will be installed in the system connecting West End's Ryan Street stormwater drain to the Brisbane River, next to the West End ferry terminal.

Residents in the Ryan Street area raised their concerns at river water rising up through the stormwater drains and flooding their homes before the river broke its bank in January 2011.

Lord Mayor Graham Quirk said the work would take about seven weeks.

“This is the first time West End has had backflow prevention devices installed as a part of the current backflow program," Cr Quirk said.

"It is one of the areas we have been able to fast-track for this financial year, given the significant progress being made to finalise flood modelling and design works," he said.

The two West End backflow valves will bring the total to 15 installed since 2012.

Council data shows the backflow valves now in place could ease flooding in 1500 properties.

Backflow valves have been installed in the river in Rosebery Terrace at Chelmer, Vivian Street in Tennyson, Moray Street in New Farm and Cribb Street in Milton.

The scheme started with backflow valves being put in place in the river at Alice, Margaret and Charlotte streets in the central city.

By July, new backflow valves will be installed at riverside stormwater drains at Leybourne Street at Chelmer, James Street in New Farm and at Castlemaine Street in Milton.

Experts say the valves ease localised flooding, but will not stop flooding.