Raising the road one option for flood mitigation

The other five options propose improvements to the north Deniliquin levee system, which is an informal levee system reliant on maintenance from private landholders.

These include filling gaps and holes, but also one proposal to raise the levee to the 1-in-100 year flood level.

Council will further investigate each of the options before making a decision on how to proceed.

At the peak of the 2022 flood, the Edward River at Deniliquin reached 9.2m - which is major flood level.

Water covered parts of Davidson St, and inundated homes on both sides of the street.

In the aftermath, long-term property owners along Davidson St and its arterial roads called for a review of the town’s flood levee protection, and requested more formal arrangements to be implemented over north.

Residents on the northern side of Davidson St, in particular, felt let down by the approach to flood protection measures.

They believe they were not offered the same level of assistance from emergency authorities as residents in other areas - not even the same as residents on the other side of Davidson St in some cases.

They also claim those authorities were reluctant to take heed of local flood movement evidence, rather than just official modelling, before the north Deni flood situation reached crisis level.

The water was rising from the north and the south.

With little time to prepare and remove themselves, large sections of the community and emergency services rallied to put sandbags in place.

Large stockpiles of dirt were placed all along Davidson St itself to create extra temporary levees, and warnings that Davidson St might be closed and access from north to south cut off thankfully never eventuated.

In addition to lobbying Edward River Council to look at options, the landholders also met with Federal Member for Farrer Sussan Ley to look at federal programs and grants.

In a report to council, director infrastructure Mark Dalzell said WMA Water were asked to investigate mitigation options to manage flooding in the Davidson St area, based on the November 2022 event and previous flood history.

Mr Dalzell highlighted that the Davidson Street levee is not a formal levee and is not council controlled.

Property owners are able to manage the levee on their land as they see fit, and in some locations the crest of the levee has been reduced or the levee removed.

Council would require the support of these property owners to implement some of the options.

“In terms of mitigating flood events in the area the report notes work on the existing levee structure so that it can continue to mitigate more moderate flood events up to 10 per cent AEP,” Mr Dalzell said.

“Council staff support these options, noting how the existing levee structure has performed in the past.

“Solutions such as the use of temporary levee barriers should be investigated as low impact methods of reinstating the levee during events.

“Options such as raising Davidson Street or raising the existing levee structure are challenging projects where the costs of undertaking the works are less than the benefit that would be achieved.

“Whilst this does not address the localised impact on properties in Davidson Street, it highlights that further investigation into these options is required before they can be supported.

“Implementation of these options will be through delivery program and operational plan actions and projects as part of future budgets.

“Also, from the report as well as observations during November 2022, council will reassess and revise as necessary its flood action plans so that events where Davidson Street may be overtopped are better managed.

“Many of the actions undertaken during the November 2022 event were based on experiences from the 2016 event and similar learnings from the 2022 event will be incorporated into council's planning. It is noted that this planning will be done in conjunction with emergency services such as SES and police.”