Flood Mitigation is a hugely anticipated part of the Lismore and Northern Rivers rebuild. While the complete recommendations from the CSIRO study may be two years away, there will be interim reports delivered to the State Government and the NRRC that may allow flood mitigation work to begin early in some form. Reports like the Flood Inquiry from Professor Mary O'Kane and Mick Fuller that is due at the end of July.

As part of the Lismore App's recent conversation with David Witherdin CEO Northern Rivers Reconstruction Corporation, we asked for an update on flood mitigation.

"I've certainly had conversations with community leaders here and I know a number of people have certainly been under the view that there's really easy flood mitigation measures in place that that will just take away the risk to Lismore. We need to be really clear around the fact there are no easy opportunities, if there were they would have been taken well before now, and let's understand that this levee we've got in Lismore only gives us protection for a one-in-10 year event and I think for for any city that's an extremely low level of protection."

"The design standard for new development is sort of one-in-100 (years) plus a freeboard, a buffer on top of that of usually 500 to 800 millimeters."

"We'll never be able to achieve that in many areas here. There's no way we can get that, there's no easy solutions in terms of dams, in terms of levees, any of those things."

"So, the end of July, we will have the recommendations of the flood inquiry, but in parallel with that the CSIRO are leading a large piece of work in terms of modeling. They've been going right around the district. They're doing a six month piece of work to aggregate all of the pre-existing modeling data that's been undertaken right across the region from within councils. State governments are right across the sector. Later this year, they will make some recommendations into what what they'll call some no regrets recommendations to be implemented right away.

What does 'no regrets' recommendations mean?

No regrets means that we don't need to wait for further evidence to move forward on some of these things. We know enough now to get going."

"The Commonwealth Government has certainly got funding available there in the next financial year to support the implementation of measures as well."

"But they're (CSIRO) also doing a really sophisticated modeling piece on the Wilson's/Richmond river catchment. They've got about $11 million in funding to do that."

"They've been flying LIDAR over the top of here, over this whole region to get the absolute detailed topography of that, boats in the river, getting what's called bathymetry so they understand the shape of that whole river system and then they can build up a really sophisticated dynamic model."

"That's about 18 months off, but once we get that, that is a really powerful tool, because then it enables us to introduce different mitigation measures in all parts of that that catchment, which helps the whole area."

"The ultimate mitigation measures does rely on the best science, the best evidence, and there's no quick way of getting that but all that's happening as rapidly as it can. I think, in sort of that 18 months to two year period, we're gonna have a sophisticated model at an international level there in terms of what we can do and that will enable us to really optimize any controls."

"I don't want anyone in the community to have this expectation that there's a silver bullet solution to any of this because I don't think there is. I think there are things that will give incremental levels of protection but there's no game changers there. I hope I'm wrong."

"We want to bring the best international expertise to solutions as well. I just had a meeting here with Southern Cross Uni around how we can set a partnership up. They've got a great network with other Australian universities, international universities in terms of floodplain management. So, we're really keen to sort of exercise that partnership, use their thought leadership as part of what we do within the community here too."

When we are talking timing, is it feasible that we could see some 'no regret" flood mitigation by 2023?

"I certainly give the commitment to the community that we will share the results of all this stuff as we work through it. So, it's not just just gonna happen and be hidden away and they'll never see it."

"I think it will be complex, some of it, but there's a commitment there to get out, engage with the community, and explain what we can do, what we can't do and why we can't do it which I think is really important."

"The other thing is I think it's really important that we are able to either prove or debunk a number of the myths around different things as well because people have all sorts of views that are based on the mouth of the river because of the sedimentation there so that caused it, or because of the highway at Woodburn, it's backed up from there because of other SLUB works that have happened at various times."

"I think we owe it to the community to use the modeling to either confirm or deny that, bring the evidence to it and that evidence should be absolutely definitive."