A Canberra flood mapping overhaul has updated the risk assessment for a one-in-100 year event, reducing uncertainty and allowing insurers to fine-tune premiums.

It follows an ACT review and reassessment of flood levels for eight catchments, using latest technology to improve accuracy and predictions for a major event.

“The ACT flood data has allowed the Insurance Council of Australia (ICA) to quantify the flood exposure to Canberra residents with greater precision, which will allow for more finely tuned premiums,” ICA spokesman Campbell Fuller told insuranceNEWS.com.au.

“The release of this initial data has done much to reduce uncertainty in the ACT, lowering the potential number of flood-exposed land parcels by 39%.”

The latest information will be incorporated into the National Flood Information Database.

Canberra suffered flooding in February when the overflowing Sullivan’s Creek affected Lyneham, but previously its only major flood was in Woden in 1971.

The city’s artificial lake system was designed to create settling ponds for stormwater from the suburbs, minimising the risk of major incidents.

“While the likelihood of riverine flooding in the ACT is low, the maps will be important in helping plan the city and potential mitigation actions, and helping the community better prepare for potential riverine flood conditions,” Planning and Land Management Minister Mick Gentleman said.

Fewer than 200 buildings across Canberra and some public infrastructure such as roads are at risk of damage from the type of flood that has a 1% chance of happening in any given year. The ACT Government has sent letters to residents and business owners on blocks that have some risk, and there is a phone line for inquiries.

Community information sessions will be held in Mawson, Weetangera and Ainslie, with representatives attending from ICA, the Emergency Services Agency and the Environment, Planning and Sustainable Development Directorate.

The mapping was funded through the Natural Disaster Resilience Program, with matching contributions from the ACT Government.