As I have lived there for almost 70 years, I find some of your comments interesting. I doubt many other major cities experiencing rainfall of around a metre plus in a few days would cope as well or any better, unless things have changed since I dealt with them, the army are neither equipped or permitted to do anything to the dam.
Townsville is not considered to be in the wet tropics, which starts approximately 100km or so further north, but it does get very intense rainfall on occasions at reasonably frequent intervals, I recorded 680mm in 20 hours in January 98 and there have been many other occasions of very high rainfalls, the main problem at the moment is consistent very heavy rainfall in the catchment area for an extended period, usually intense rainfall such as this in the tropics, tends to last 24 to 48 hours then ease off to a more steady rate.
My understanding from civil engineer's who were in QLD gov water resources dept and the Council, is the dam flow rates are controllable by the flood gates up to about 300% capacity, over that, water will be above the flood gates and flow cannot be controlled, the possibility of that ever happening is considered extremely improbable!
Unless we get extremely heavy rain prior to 9am Sunday I expect to be a bit over 1200mm since 28th January, when I check the gauge in the morning
Yes 1998 was “the big one” for Townsville. I happened to be stuck at a relatives house not far from the Ross River waiting for the highway north to reopen for that one.
I noticed yesterday that the Ross river had already passed the record height from that 1998 event.
Townsville’s average annual rainfall is 1100mm, so to have 1200mm in these last few days is just amazing.
My comments regarding Townsville flooding are purely observational. As you know South Townsville floods on the spring tides.
Townsville has a very small catchment area which is sandwiched between the mountains and the ocean. The areas most populated are very flat and the majority of the city center and to the south and west is built on mud flats. Natural drainage is poor in a lot of suburbs (the newly built ones seam to be better then those older ones closer to the city center).
Apart from the occasional cyclone that passes by, Townsville really just doesn’t get proper rain events when compared to the surrounding areas of that region.
At only around 750 square km the Townsville catchment area is much smaller then the surrounding river systems.
The Burdekin, for example, receives roughly the same annual rainfall, while its catchment is over 130,000 square km and has only recorded 10 major floods.
You mentioned other cities getting that amount of rainfall.
The 2011 Brisbane floods had exactly that. Over 1200mm of rain fall on a catchment area of almost 14,000 square km (18 times bigger then Townsville’s catchment) in the period leading up to the actual flood, including around 500mm falling above the dams in the immediate days prior.
Poor management of the dam that was built for flood mitigation but now primarily used for water storage worsened the down stream flooding.
Which, thanks for clearing up, I was hearing the same about the Townsville dam.
Some people get a bit over excited in big events like these and I was hearing all sorts of hyped up rumors about the dam wall.
Pretty much exactly as was happening in the Brisbane flood.
It’s a big call, release more water now and flood a few homes or don’t release it and risk a major incident if it keeps raining.
Anyway, this will be one for the record books and I hope everyone gets through it ok.
Stay safe.
