A flood mitigation plan contained in a report by Italian academics compiled in 1981.
A flood mitigation plan contained in a report by Italian academics compiled in 1981. Contributed

The forgotten plan to rescue Lismore

FLOOD mitigation has been a hot topic of conversation of late, with a recent state election promise to help flood proof Lismore.

The current Flood Mitigation Plan bears striking similarities to ideas put forward almost 40 years ago.

A story in The Northern Star on April 18, 1990, was headlined: "The forgotten plan to rescue Lismore", and it questioned the lack of action on a flood mitigation plan first raised in 1981.

Italian academics Prof G Colombo and Prof A Paoletti from the Politechnic University of Milan spent 13 days in Lismore studying the town's flood problems and presented a plan which claimed to have the answer to diverting flood water away from Lismore..

It described the recurrent floods as a "disastrous calamity that not only badly affects the economy of the city, the functioning of its services and lives of its citizens, but constitutes an oppressive handicap to its commercial and industrial development".

It recognised the floods were caused by the "insufficient capacity of the fluvial system downstream to cope with the run off of the 1400 square kilometre catchment area of the Leycester and Wilsons Creeks".

Levee banks and diversion channels were offered as feasible solutions to the problem and two structures close to Lismore city were recommended.

Proposed solutions in 1981 plan

One recommendation was a levee bank, about four to five metres high, surrounding and protecting the city - sluice gates were proposed to prevent the flow of floodwater into the city and a pumpstation would help disperse water from the Lismore basin.

Another structure at South Lismore would turn the area west of the airport, normally a floodway, into a permanent lake with a diversion channel.

The lake would have a surface area of about six square kilometres and a depth of 2.5 metres.

On the western side of the lake the bottom would be shaped into a six metre deep channel to help the flow of floodwaters and improve the water renewal in dry conditions.

While plan would have required changes to existing infrastructure, including raising the railway line, the airport and roads, it was proposed it would control flooding in North and South Lismore.

The report estimated the solutions it proposed would take up to 10 years and suggested some provisional measures could be necessary in the interim.

The report ended with a positive message: "Our definite opinion is that structural measures should be adopted as soon as possible".

"As the flood problem can be solved, then it must be solved"