Townville's Floodplain Management Strategy

We are now just over 3 months from the night that the gates of the dam were opened and Townsville became inundated with imminent flooding.

You will all remember that the dam hit 247% capacity at midnight that night. It was frightening, frantic and traumatic to say the least.

Many were evacuated. Many lost their homes and their possessions.

Shopping centres, small businesses, livelihoods were and continue to be disrupted.

Employees could not go to work. Employers wondered when they could re-commence business. Many business owners wondered what state they would find their premises, many left inoperable.

Schools closed, day-care centres closed, our university closed.

Our hospitals however remained open.

Our infrastructure was damaged. Roads were closed. People of Townsville put their lives on the line.

Large quantities of sand were dumped in a location with hessian bags and shovels. Men, women and the children were frantically shovelling sandbags to take home to barricade their property.

Re-building efforts are underway, but for some the remedial work has not even started.

Some have had pleasurable experiences with their insurers and loss assessors. But most, from what I hear, have experienced nothing but frustration, stress, constant questioning about items claimed, delay and being uninformed about the status of their claim. Most have had to replace necessities before any financial outcome was or has even been achieved.

Some streets now feel like ghost towns. People are camping out the front of their homes in caravans with possessions locked in shipping containers, waiting patiently (because there is no other option) to move back home.

More than 1,800 people affected had sought housing assistance.  Many still remain in temporary accommodation.

The photo above was taken from my colleague, raw and in the moment that her street, that is Ackers Street, was inundated.

Flood mapping

I am a property lawyer and have an interest in how the 2019 Townsville Flood is going to impact the Townsville City Council's flood mapping data

When you purchase a home, you generally do a "flood mapping search" that tells you whether your property is subject to inundation resulting from broad scale regional flooding and does not reflect local flooding or inundation due to storm-tide. 

Below is a map that I can create through TownsvilleMAPS Flooding that I would generally come across.

The last set of modelling was completed and mapped in 2014.

You will recall that on the night the dam gates were opened, the Council released a set of maps showing potential inundated properties. These maps were based on a hypothetical scenario analysis undertaken by the Council using information from SunWater and the Bureau of Metrology and showed the potential inundation from the Ross River flowing at a rate of 2,000 cubic meters per second. The maps were so radically different to what I usually see in a standard flood mapping search that I immediately became alarmed. Townsville was going to experience a flood event that we will probably not see again for another thousand years.

The map shown below is Map 2 of the group of maps that were released on 3 February 2019. As you can see, the amount of potential water inundation is almost inconceivable. Maps 1-7 can be accessed here: https://www.townsville.qld.gov.au/about-council/news-and-publications/media-releases/2019/february/map-of-potential-inundated-properties

I called on Council to tell me if the data from the 2019 Townsville Flood is going to be used by the Council to calibrate the flood model. The answer I got was yes.

The flood maps that we obtain when one purchases a property are updated every 5 years.

The flood maps are updated through a rolling program project that takes 3 years to complete which is called the Townsville Floodplain Management Strategy.

The Townsville Floodplain Management Strategy focuses on the combined floodplains of the Ross, Bohle and Black Rivers and neighbouring floodplains of Althaus and Bluewater and Alligator Creeks which is performed in conjunction with the Qld Government.

Generally, the project includes:

• Ground level surveys
• Detailed flood modelling
• Floor level studies
• Community input surveys
• Flood hazard analysis
• Development of the management strategy
• Options analysis based on community input and the flood hazard analysis results

When the flood maps are finalised, they will be adopted within our Planning Scheme – the Townsville City Plan.  

I suspect that this time around, the public consultation component of the program will be substantial and will heavily shape the analysis used in preparing the floodplain management strategy.

I do not know when the strategy will be released and the new flood maps will be available. Council tell me that they are working on them.

As a result of the updated modelling, questions spring to my mind. The first is, if the Council include data from the 2019 Townsville Flood, what will happen to land that remains undeveloped.

What will it mean for the land developers, for the people who have a block of land waiting to build a new residence, for vacant commercial and industrial sites. Will Council expect a new standard for floor levels of all habitable rooms? Will Council require additional built-form outcomes to mitigate against flood damage?

The current flood hazard overlay code of the Townsville City Plan provides developments under certain criteria require floor levels of all habitable rooms to be a minimum of 300mm above the 1% annual exceedance probability (AEP) flood level.

How will the new mapping affect persons living in an area that experienced substantial inundation in the 2019 Townsville Flood. Will these people have trouble selling their homes?

This is my second note on the 2019 Townsville Flood. As I continue to find out more information on the development of the Townsville Floodplain Management Strategy I will continue to update the readers again.