A study commissioned in the wake of the Boxing Day floods looking at how to reduce the risk of a repeat says “significant progress” will be made by 2021 but work may extend beyond that date.
It suggests building work could start by the end of next year if design work and the letting of the construction contract go to plan.
The Environment Agency report says that “everything possible will be done to accelerate all elements of the scheme and where opportunities present themselves to deliver individual elements early these will be taken.”
Leeds City Council leader Judith Blake said: “Another announcement about the process does indicate that we are moving in the right direction.
“However 2017 is still a long way off and we’re far from seeing anything actually happening on the ground.
“We appreciate that these things take time, but promises have been made before and we’ve been sorely let down, as we were when the government rejected funding for the 2011 Leeds scheme.
“In order for us to be able to give many concerned residents and businesses the reassurance they need, we need certainty and confidence that Leeds will get the flood defences that the city needs and deserves.”
Around 2,000 homes and 400 properties in Leeds were affected by the Boxing Day floods which also cut off the A65, one of the main routes into the city.
The Environment Agency report suggests new “raised defences” are likely to be needed along the River Aire between Newlay and the city centre.
The use of engineering such as walls and embankments will be looked at alongside ways of storing water upstream, improving drainage and the use of hedge and tree-planting.
In the Budget last month, the Government promised £35m and suggested further pledges would follow to meet the estimated £65m total cost of the measures likely to be recommended.
The Environment Agency report echoes that position but warns that extra local funding may be needed for any measures judged to go beyond what is considered a “good standard of flood protection”.
Adrian Gill, flood risk manager at the Environment Agency, said: “This report is an important milestone for the future of flood risk in the city, and we will now be working closely with Leeds City Council to take a catchment wide approach, considering how both engineered and natural flood management measures can provide a higher level of protection for communities in Leeds and around the River Aire.”
Before the floods struck, work was already underway on improvements to city centre flood defences part-funded by the council.
But the devastation caused by the Boxing Day floods has led to fresh scrutiny over the Government’s decision not to finance a £180m scheme to protect the city put forward in 2011.
The money promised in the Budget to improve Leeds flood defences will come from an increase in the insurance premium tax paid by everyone who takes out insurance policies.
York and the Calder Valley will also benefit from a share of the £150 million earmarked by Chancellor George Osborne to upgrade flood defences in response to the winter floods.