Australian Flood Crisis – Brisbane Smashed – Worse Than 1974

This is happening now as I write.

UPDATE 4 Thursday Morning 10.30 AM Australian Time.

Link to most recent Brisbane Courier Mail site: This is the home page with numerous stories, images and videos on that page.

Link to most recent ABC News site: Here there are numerous videos and related stories, all shown under that main image at the page.

Link to image gallery of images from the flood in Brisbane.

Brisbane residents woke this morning to images of what a war zone might look like. Thankfully, the flood peak, the first such peak passed at high tide in the early AM hours and the water level did not get to the expected 5.3 metres in town, which makes it a lower level than that of the great flood of 1974.

Having said that, the damage this time is far far worse than it was then because Brisbane has changed so much in those intervening years. Close on 12,000 homes have been destroyed, and many more than that will be uninhabitable. The CBD is a ghost city at the moment.

Electrical power is still cut to almost 200,000consumers and is likely to remain cut for many days yet. Then, every home and business will have to be checked thoroughly before that power is restored.

The fact that the city has had some sort of minor reprieve is due in the main to what is an incredible juggling act. You may think I am tending to concentrate on the role of the huge Wivenhoe Dam further up the Brisbane River, but if it was not for this monster dam, that damage in Brisbane would be of a scale considerably worse than the catastrophe it is right now.

To understand this better, you need to know just what has happened here.

This huge rain event that led to this flood fell directly into the catchment areas of the two main dams on the River, Somerset, and Wivenhoe. That rain found its way into Somerset first, runoff from ground already saturated with no capability to absorb any more, hence it then became runoff into the river system. The water holdings in Somerset dam filled at a dramatic speed to a level approaching 180% of its capacity. As difficult as this may be to understand, the dam is considered at 100% when it is holding its maximum water supply water. That remaining percentage over and above that 100% is the dam’s flood mitigation capacity, its ability to hold back water to prevent major flooding. As more rain flowed into Somerset, and it filled rapidly, then huge amounts had to be let out of the dam. The floodgates were opened to maximum and water flooded out of Somerset.

However, the rain water runoff into the dam was greater than what was being released, even at its maximum.

The water pouring from Somerset goes directly downstream and into the monster dam, Wivenhoe, which prior to this event was at 100%, with its flood mitigation compartments still to play their role. The flood mitigation compartments in Wivenhoe filled rapidly with rain from its catchment and also what was coming in from Somerset. The floodgates of Wivenhoe, all five of those huge gates were opened and at one stage, water was being released at the rate of nearly 700,000 megalitres per day. (around 185 Billion gallons of water a day) This was an absolute necessity. You might think that had they not released that amount of water, then the flood in the city would not have been so bad, because Brisbane city is directly in the path of all that water. But what was happening was that water was flowing into Wivenhoe, at a greater rate that what they were releasing. Wivenhow rapidly filled to close to 200%, nearly all of that in its flood mitigation compartments.

A day later, Wivenhoe lowered its release back to around 220,000 megalitres per day, and right now it is still releasing water at around that same rate.

Now comes the juggling act.

The level in Somerset is gradually falling, but is still well above 150%. Wivenhoe is still around that 195% mark.

Brisbane is in major flood.

Water still has to be released from Wivenhoe so that those flood compartments can diminish, because if there is another rain event, then there is nowhere for that water to go.

So those releases from Wivenhoe will keep the level in the Brisbane River in the capital city at a high level for a few days yet.

It is imperative that they empty those flood compartments.

So while Brisbane endures the worst natural disaster in Australia’s history, it would have been a disaster even more catastrophic that it already is.

Even though those releases from Wivenhoe probably contributed to this huge flood event, that monster dam is probably what has saved Brisbane.

I wouldn’t want to be an engineer trying to balance all this out for all the money in the World.

When Wivenhoe was constructed, it was thought that the flood of 1974 could never happen again.

Nothing could have stopped what has happened here, and without Wivenhoe, that would have been close on an extra 2.2 million megalitres of water flowing directly through Brisbane which would have made this a flood of unspeakable proportions.

UPDATE 3 Thursday Morning 1AM Australian Time.

Link to most recent Brisbane Courier Mail site:

Link to most recent ABC News site:

Some of the most harrowing stories have come out of the small town of Grantham in the Lockyer Valley. Homes were washed away and floated with the fast moving river through town with people on the roofs of those houses. There are images in the following gallery that show the main rail bridge further down the creek where cars were smashed into, and that is where many of the remaining people still on the missing list are expected to be found.

This is a link to a Gallery of images from Grantham.

In Brisbane, the good news is that the river peak is hoped to not reach the level that was expected. That new level is barely 8 inches lower than what was expected, but that 8 inches effectively means up to 5000 homes will not have water rising over their floorboards. 23 suburbs have been affected by the flooding. Power is cut to around 160,000 consumers. Brisbane is holding its breath as that peak is expected at the day’s first high tide at around 4AM, and there will be a further high tide late in the afternoon as well.

What is happening now with the Brisbane River is that pontoons have broken away and are floating down the river, and smashing into bridge pylons. There is fears that a large car ferry up river may have to be sunk so that it does not become a major threat if it breaks its moorings.

Brisbane River City Cat

Brisbane being a river city has an extensive system of ferries crossing the river, and also as a floating taxi service. The major service is the City Cat service and an image of one of those catamarans is shown at right. What has happened now is that, while those many city cat boats have been taken to safe moorings, the ferry terminals on the river have all been wiped out completely. Brisbane Lord Mayor Campbell Newman has said that it will be months before the service will be back in any semblance of operation. Most of those pylons floating down the river are these ferry cat pontoons, and even though floating, they are concrete in construction, and float on large rubber bladders.

What is also breaking away is the river walk, a large foot traffic pathway along the banks of the river, and large sections of that are also floating off down the river.

High rise accommodation buildings on the river are also being evacuated as well.

The huge Wivenhoe Dam is currently at 196% of capacity, and it can effectively hold up to 225%, as the dam was constructed with major flood mitigation as an essential part of that construction. Without that huge dam in place, this disastrous flood would undoubtedly be a quantum level worse than it is.

UPDATE 2 Wednesday Afternoon 3.30 PM Australian Time.

Link to most recent Brisbane Courier Mail site: This is the home page with numerous stories, images and videos on that page.

Link to most recent ABC News site: Here there are numerous videos and related stories, all shown under that main image at the page.

Link to Bolt Post at this site. There is an amazing video there of some footage taken in Toowoomba two days ago now, and also a link to video footage showing the impact in Brisbane of differing flood heights.

The Bremer River At Ipswich 12 January 2011

 

This image shows homes in Ipswich, which is on the Bremer River.Ipswich is the closest major city to Brisbane, and is around 25 miles from the State capital, Brisbane.

The Bremer River has risen very rapidly as it always does in any flood event, even of a minor nature. The River level on the Bremer is expected to rise to 20.5 metres, which is well above the level it was during the 1974 flood.

Currently, there are 3000 homes that have been evacuated, and with the Bremer continuing to rise, that number is expected to double.

Some of the links in the above Courier Mail link will take you to video footage of the situation in Ipswich.

The Bremer flows directly into the Brisbane River, and all this water combined with the huge flows from the monster Wivenhoe Dam are only adding to the rising flood in the CBD of Brisbane. To further exacerbate this flood, there is expected to be major King tides expected on Thursday.

In Brisbane, the River is continuing to rise. Many thousands of homes have been evacuated there, and that number is rising exponentially.

Power has been isolated in some areas so that any faults that may occur are not felt further up the electrical supply chain, and blacking out the entire city. So far, 95,000 consumers have had their power cut off.

There has been major runs on all the supermarket chains as the shelves empty completely, and now with the power being turned off, all that has gone to waste, as they cannot keep food cold, nor cook what they already have.

The CBD is a ghost area today, as everybody has been told not to come to work.

High rise accommodation in the city is also being evacuated

As I have mentioned earlier, this is a disaster now becoming astronomical in scale.

Photo by RaeA For a larger view clck on above Image or here.

The image at right shows people moving household goods from residences where rising waters threaten in the Brisbane suburb of Rosalie.

Thank heavens that the rains have stopped for now.

UPDATE – Wednesday Morning 9.30AM Australian time.

Link to Brisbane Courier Mail site: This is the home page with numerous stories, images and videos on that page.

Link to the ABC News site. Here there are numerous videos and related stories, all shown under that main image at the page.

At that ABC News site above are some pretty graphic videos of what is happening in Brisbane. Only later did they finally get into the small Lockyer Valley town of Grantham. When they did, the scope of the disaster only became evident then. This is only a small town, but what happened here is incredible. Houses floating down the fast flowing flood through the centre of the town, those houses with people still on the roof. There are two videos at that link related to what happened in Grantham.

At the moment, the overall death toll is moving into the teens, and it’s feared at least 100 people are still missing, and grave fears are held for as many as 20 of those missing people.

Water is still flooding out of the huge Wivenhoe dam, at a rate smaller than what is flowing in. There was nothing that they could do to hold this water as that monster dam was holding close to 200% of its capacity, the vast extra being in the flood mitigation compartment of that huge dam. The rain has stopped now, for around 16 hours, and it is hoped that what can be pushed out of those huge spillway gates will gradually start to overtake what is flowing into the dam, coming mainly from rainfall in the Catchment and from Somerset Dam, directly upstream, also close to 180% full, and also pouring water down the spillways at a rate less than what is flowing in from its catchment.

All this water is flowing down the Brisbane River through the city of Brisbane.

Power has been cut to areas already going under, mainly so the water does not cause major electrical faults that might cause the whole electrical supply to go down, which would be a disaster of unprecedented proportions.

I cannot post videos from those sites, but I can direct you to the ones that should be viewed, and while you may watch all the videos, those ones about Grantham are the ones worth watching.

On the ABC Current Affairs program (The 7.30 Report) last night there was a further story on the terrible happenings at Grantham, with interviews of some of those who were affected, when this small town was virtually wiped off the map.

This is the link to that video.

As this huge natural disaster unfolds, there will be many more stories, and I’ll try and keep you updated as matters break here in Queensland.

Tuesday Evening Australian time

Link to Brisbane Courier Mail site: This is the home page with numerous stories, images and videos on that page.

Link to the ABC News site. There will be video clips at this news site later as those clips from the major news bulletins get posted here,

Image Galleries at that ABC News site

The Post at this link details what happened in Toowoomba yesterday with some amazing videos.

I have been watching the weather radar on and off throughout the day, for nigh on twelve hours now. It has been a solid wall of water falling as rain for virtually all that time, and it has been centred over the Brisbane River Valley. Some areas in that area have receives over 18 inches of rain in that period.

When combined with the awful rain and the drama of yesterday, this, on top of that is turning into a catastrophe of major proportions.

The Rivers have all come up to levels never seen before, and it has happened in a matter of hours.

The same happened back in 1974, the worst flood disaster in the history of modern Brisbane.

Brisbane is the Capital city of the State of Queensland.

I have been Posting about the floods centred around the major city where I live, Rockhampton since the day after Christmas, and now the flood drama has moved into the South East corner of the State, the most heavily populated area in this State.

After that 1974 flood event, the Government of the day constructed the huge Wivenhoe Dam. The main purpose of this dam was to provide a secure water supply for that south east corner, and also to act as mitigation for any future flood of the size and scope of that 1974 flood.

As recently as 30 months ago, this huge dam was sitting at only 17% capacity.

Following some quite large rain events, the dam slowly filled, and it has been close to or at 100% capacity for around 10 months now.

During that 1974 flood, the only dam on the Brisbane River was the large Somerset Dam. Besides having a 100% capacity, it also has flood mitigation capacity as well. That dam was full, and the flood mitigation capacity was also full. All it could do was to release water into the river. At the same time, there was a huge king tide which exacerbated the effects of the water flowing down the river, and a huge flood backed up into Brisbane causing 14 deaths,  countless homes lost, and a damages bill of $200 Million at the time, and in those days 36 years ago that was a huge amount of money.

The decision was made to construct Wivenhoe, with all that extra flood mitigation capacity. It was constructed on the same river, and directly downstream from Somerset. It was the perfect place for a huge dam of this size, and it was first proposed in the 1880’s and again revived in the 1930, at neither time proceeding to the construction phase following the extensive surveying done at those earlier times.

After that 1974 flood, and Wivenhoe was constructed, Brisbane stayed relatively safe from flooding.

Now, after these last two days, the flooding has become monumental.

Somerset is at 176% of Capacity, with its mitigation capacity full, and the dam desperately pushing its maximum flow of water as it can down the spillways.

All of this water is flowing directly into Wivenhoe.

Wivenhoe is currently at 196%. Its flood mitigation capacity is also at its maximum, and is actually holding more in that area than it was thought it could hold.

The spillways there, all 5 of them have the gates fully open, and water is pouring out at its maximum rate, straight into the river and then downstream into Brisbane city. The water pouring from those spillways amounts to around 600,000 megalitres each day. This is around, and wait for it, 160 Billion gallons of water each day. As hard as this is to believe, here is the link for that. Scroll part way down the page to where it says ‘Latest News’, and see the latest release details.

We can think long and hard that in all reality, the purpose of Wivenhoe has in effect failed.

Not so.

Without Wivenhoe, the situation would be infinitely worse than it is right now.

This has the potential to be the greatest natural disaster in Australia’s history, and that is not sensationalising the matter.

I will be updating the Post as matters unfold, but as you might imagine, it is almost impossible to keep abreast of all this.

Tagged: Australian Floods, Brisbane Floods, Queensland Floods, Wivenhoe Dam

Posted in: Australia, Disaster