Flood Plains are for Floods

by Viv Forbes

Photo sourced from the UK: Mail Online
River quango has allowed 190,000 new homes on flood plains since 1996 despite concerns they could be uninsurable

Every month or so TV screens are filled with images of desperate people somewhere battling a flood.

Floods have been reshaping the Earth for billions of years. And some past floods were far larger than modern floods, evidenced by the width of many flood plains - seldom are they completely flooded today.

The majority of cities and many country homes were built on flood plains, and for good reasons - closer to water, with fertile soil, better groundwater, flat country that is easier to build on, near good fishing holes and shady trees, and periodically re-fertilised with silty topsoil. Sensibly, many early settlers built their homes on stilts.

 

We hear alarmist stories about the soaring costs of floods. That is not usually because the floods are bigger – it is just that more people are building more costly homes and infrastructure on flood plains near the mouth of scenic rivers.

Those who choose to build/live on flood plains must accept the costs that go with it – occasional flooding and expensive flood insurance. But a nice home on flood-prone land will usually cost less than a similar home on the hill with views.

Long term flood problems are increased when government steps in and “helps” those who buy/build on flood-prone land with repair subsidies, public works or insurance caps. This allows risk-takers to escape the real cost of their decisions. Then more people build on flood plains.

Flood diversions and levees may not help – too often they just shift flood water from one piece of land to another. Commonly, they also increase water speed, thus increasing the erosive power of the flood.

But governments must ensure that essential infrastructure is relatively flood-proof – roads, railways, airports and electricity should remain operational during most floods. And strategically placed dams will moderate the extremes of both floods and droughts.

Global warming can’t be blamed for more floods because, for 17 years, there has been no global warming.

Flood plains are for floods. Those who choose to live there must expect to get flooded.

Viv Forbes,
Rosewood    Qld   Australia
forbes@carbon-sense.com

Photo sourced: Can you move an Entire town up hill YES YOU CAN in QLD
This blog documents the flood damage to Grantham in the Lockyer Valley Qld and how the houses were rebuild on higher ground off of the flood plain. 

Previous related post:

Learn and construct to cope with future natural disasters

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Natures power

This is a quick post to reflect on the sheer power of flood waters. This is not meant to be a criticism of the CSG industry; ex cyclone Oswell caught a lot of people out and when you have to cross a flood plain and a heavy rain event occurs the proverbial can happen.

Photo sourced from Beef Central, Oswald leaves trail of delight and despair

 

This is a photo of 30 lengths 42 inch diameter gas pipes that were welded together across a flood plain at Calliope, inland from Gladstone, sitting on mounds of dirt in preparation to be buried. The wall thickness of these pipes are about 3/4 inch. Individually each pipe length weights about 4.4 tonne. Not only did the water shift the pipes across the flood plain but also kinked the pipe. 

 

That's right, kinked, there must have been an incredible amount of force in the water to do that!

 

The pipe construction company would know how much hydraulic force it takes to bend a pipe. They do come along with a machine to make up some of the lesser degree bends on the pipeline easement. They bend x amount of degrees then move along x inches to bend the x amount of degrees again. They keep doing this until the right size bend is created. They have to make it gradually and smooth because the industry sends "pigs" up inside the pipe for various reasons. 

Learn and construct to cope with future natural disasters

As the flood waters started to ease and a stocktake started on the damage caused by ex-cyclone Oswell that travelled down near the entire length of the Queensland coastline and well into New South Wales, two regular print columnists published articles on the 31^st January calling a visionary and practical approach of looking to how we can reduce the impact of natural disasters in the future.

Andrew Bolt wrote an article, Nation must learn from natural disasters, where he concentrates on towns and cities that flood regularly, where a lot of money is spent of repairing after a flood and helping people to get back on their feet but little spend on prevention measures such as levy banks.

Personally I don’t believe that all can be solved by levies or dykes as in Bolts nation of origin, Holland. Historically towns had to build down close to a major source of water; these days we have the means of moving the water to the houses. I don’t believe that in locations of high flood risk that sometimes the cost of constructing a big enough levies for the worst of floods would be far greater than shifting the people out of the worst impacted streets.

Senator Barnaby Joyce wrote in his weekly column in The Canberra Times, Acts ofGod, but not much remedial action in Parliament, where he made some very good points about Australia’s transport and communication networks and their current inability to cope with natural disasters.

 

Cartoon thanks to Broelmann

 

"The major infrastructure corridors along the coast are again under pressure or cut. The Telstra fibre providing the communication link for north Queensland was cut because of flooding.

The justifiable focus on the current problem of flooding should be accompanied by a long-term solution to alleviate some of the problem. 

The course of innovation is not lineal, it is more chaotic, but in the period of this government there has been no plan that has dealt with the year-in, year-out problems of floods, congestion and safety of moving goods along the same corridor as people, along the coast. It should not be a surprise any more that somewhere between Cairns and Melbourne at some point in summer there will be a flood, and generally at many points along the coast.

We need an educational system that does not leave Australia falling behind our Asian neighbours. More than two sealed roads from east to west across our nation would be very 21st century if we could manage it. We should plan to develop our nation's north so we evolve from the southern crescent economy of Lachlan Macquarie's day to one that can make the most of Asian middle class opportunities. The capacity to move product on long haul rail from our second biggest city, Melbourne, direct to our nation's third biggest, Brisbane, should have happened years ago"