Pumps for Flooding Situations, an Important Issue for the Future

How many and what size pump to make an impression on the flow?

and to what dry destination ?

Yeah. When Mother Nature decides to cut loose, whether it's a flood, hurricane, tornado, earthquake, volcano..................you name it.............mankind does not possess the technology to stop it.............probably never will.

world is full of people attemping to take away situations like that, so we have to give them the best technicall solutions

Sure, you are right. Moving the flood from one point to the other is not the solution. We need more intelligent to manage the flood, with PREVENTION.

Water, that wonderful, basically incompressible fluid that supports all life on Earth.

Flood mitigation is something close to my heart. Current technology and realistic physics seems to lead to one strategy that is effective.

PLANNED control of the volumes involved to extend the duration of the flow over a longer period (and thus lower the peak experienced) seems to be the most effective solution. The use of detention areas to intercept and store floodwaters is having significant effect in Aus.

Recent floods in Brisbane would have been worse if a particular dam had not been constructed nearly 20 years ago. That dam has redundant capacity that was fully utilised to smooth the peak of that flood. Recent floods on the coast near Kempsey were mittigated by the detention basins upstream of the town. This system is not yet completed, but benefits have been already seen. In cities in England, there is provision for houses to have rainwater tanks with controlled release of the excess water, effectively smoothing the peaks from storm events in cities.

Usually, when flooding is happening, adjacent watersheds are also getting wet. Moving the huge amounts of water involved to the necessary distances while technically possible is a ridiculous appraoch to the issue. It would be cheaper to relocate the population rather than have the necessary excess capacity installed for every possible flood scenario.

I've seen localised downbursts where 17" of rain fell in 45 minutes causing significant local flooding. Sometimes, it's just an act of the almightly and we as individuals need to respond to what is happening rather than to lament the possibility of someone else doing something on our behalf.

Dams are the best solution, they can be combined with irrigation projects taking the water where it can be used. Dams have a lot of opponents however. I remember hearing about lots of drought problems in Australia. Do you have any large dams and irrigation schemes there?

Yes we have some significant dams here, but they have other issues especially when seen as a resource for irrigation water and such.

There is an international flow index used to indicate flow variability for rivers and streams (Maximum observed flood flow over minimum normal flow). The rest of the world regards factors like 14 as extreme variability. Australia would not see 1400 as abnormal.

For instance, the Ballonne River near St George in Queensland normally flows through a 500mm diameter culvert, but recently the river was 13.6m deep across a 300m wide rectangular watercourse and extended nearly 5km each way with flow along the floodplain as well. This happened twice in the last 12 months, but was the first such flow for 20 years in that network.

We have river systems that may only flow on week in any particular year. Dams on those systems mean that some of them have not flowed for the past couple of decades. Evaporation and irrigation could use many times the annual rainfall on large parts of this country.

Our real challenge is to maintain environmental flows so that the inland rivers don't get sterilised by drying up.

conversely, our coastal rivers have more reliable water delivery, but social use of the water means that even these can be overutilised.

Water is now being seen as a national resource and we are learning how to manage the stakeholder needs across community. We are progressing, but have a long way to go.

primarily dams are useful for those cases in where flood risk is high

Dear Just an Engineer:

Thank you for your interesting contribution, I totally agree with you. Here we have a lot of experts for many solutions, but at short time. Really we need to take enought time to analize all possible flood scenarios, undeer a long time horizon.

Floods are useful if we are able to manage the situations, not avoiding them, but taking advantage of them, for water supply, crop irrigation, or as a reservoirs for dry season. Without computers, without Internet and without satelites, our ancient indigenous were far more intelligent to handle the flood.

We just had this discussion here:Nationwide Water Piping and Ditch System,

Please go there.

sure, an interesting discussion

Stay out of the floodplain of rivers and major streams, and don't build there, unless yu want to build very expensive dams, reservoirs, and over flood control measures.

That's all I'm going to say about this issue. High time some peeps use common sense all around the world......DON'T PLAY IN THE WATER!!!! LOL

common sense is the least common of the senses

As the world, unfortunately, overpopulates many more will be living in flood plains. One way to survive is to dredge canals, and build home sites and agricultural land above the flood plain. Dredging will be much more common in the future. I have observed man made islands in Miami. I don't know the origin of the soil, but I don't think it was silt.

Areas like Bangladesh and the Netherlands have been dealing with this for hundreds of years. The best solution is obviously not to overpopulate, but that does not seem to be learned easily.

you need to talk to the Dutch. they've cracked it!

" Let not a drop of water return to the sea without first serving man."

Rajasinha of Ceylon