If there were years in between floods you might have something but there isn't. and you don't.
when 75% of an entire state is under severe flooding drains are not going to help you one iota...there is simply no where for the water to drain to...Dams had to be opened to prevent catastrophic loss of life etc...
This is what happens seldom. If the change is rapid, nothing before but now it happens every year several times, the region will simply not be used for agriculture. Initially. Until people start to get used to this. Some use regions a little bit higher than the average, with appropriate drainage, for usual agriculture. Some build dams to create sees, and use them for fish farms. The Ancient Egyptians have also found ways to handle the situation where a single big flood in the year is all the water they have.
You seem to think that when a nation declares a state of emergency they are just playing politics....
No. Emergencies are a normal part of life. People don't prepare for everything, but for what is known to be typical. If the stormy climate is typical, they will be prepared for this. The extremal event which happens once during your lifetime will be an emergency because the preparations will be either completely absent or insufficient. Why? Because stealing money aimed for preparations for extremal situations is a quite secure way to steal. Because it will be detected only if the extremal emergency happens. Which maybe never. And because of this, preparations for really extremal event will always be insufficient. So, there will be emergencies, and they will cause deaths. But this consideration, you should note, does not depend on the actual climate or a climate change at all. And the natural thing, if such emergencies happen, is that those who have stolen the money designed for the preparations will be punished (if possible), and a lot of new money will be given for better preparations, and they will be given in such an amount that if this 100 year event happens again in 10 years everything will be normal.
Re cyclones: The houses are not the problem, Australia has been dealing with cat4 -5 on many occasions, it is the flooding and storm surge that comes with a cat 4-5 cyclone that is the problem.
Once you know what is the problem you can learn to deal with it.
Abandoning 75% of Queensland sounds awfully radical but if things continue the way they are we may actually have to seriously consider it.
There is not a drain or a flood preventative dam that could possibly cope with the extremes that have been experienced and the situation is only going to get worse...
That's rhetorical nonsense.
You have probably never been to the Barrier Reef along the Eastern Coast of Queensland. In a few years it may not even exist due to intense die off, bleaching due to increased ocean temps. Given the sheer scale of the tragedy theer is no way the world can know what the outcome will be when this reef disappears and fails to do what it is supposed to do environmentally.
Indeed, never been there. But I know that corals are quite old creatures, thus, they have survived times which were much hotter, with much more CO2 in the air. The same holds for essentially all the other things living in the water.
Maybe it's a European perspective thingo...you can't see the horizon sort of thing...
You know when QLD is in flood like we have had recently you can look in any direction for 1000 kms and see nothing but 1 meter deep water in every direction, floating bloated cattle a few trees and a huge stink of rotting flesh. Drains? yeah sure...lol
so tell me about drains and infrastructure....? I am all ears...
Of course, it depends on your local conditions what you have to do. You ask a general question, and expect an answer in a single post what in particular you have to do in your particular circumstances? It depends on many things. If this happens every 100 years, care about good insurance, and that your home is safe enough that you can survive this. If this happens once a year, and during all the other time there is no rain at all, build dams around the place where you want to do agriculture. One dam around the deepest part on the border, for an artificial sea, the other dams around the higher parts. If necessary because the water flow down the hill is not sufficient or simply absent, use pumps to pump the incoming water into your artificial sea. there is not enough And drains with pumps, so that if there is too much rain, the water flows to the pumps, and will be pumped into the place for the see, and so that if the sea is full, it flows out of your territory. You can you use the sea as a fish farm as well as a water reservoir for the agricultural parts during the time without rain.
To compute the appropriate high of the dams, areas of the fields and the sea, and the power of the pumps, one has to know the average expectations as well as the volatility, of course also together with the changes during the year in that climate. The scheme itself will be able to work even with extremal volatility, say, one week extremely heavy rain per year. It stops working if there is not enough rain. But too much rain is not a problem. Moreover, it is a local structure, you do not depend on big structures like an Assuan dam or so, it depends only on the rain you get on your territory. With pumps, it works even in a completely flat area (which is what your description suggests). Pumps are also autonomous if you have your own machine to generate electricity and prepared enough fuel for it. For cows, one would better have a sufficiently safe barn (= sufficiently high) which remains safe even if you have no longer sprit for the pumps and no electricity. With modern weather predictions, you have at least three days to put the cows home into that barn and to care about your sprit stocks.
Does that require investment? Of course. But all the necessary technology remains the same well-known age-old. And the investment is not that large, in comparison with what a modern farm invests anyway. To secure against your 1m flood, a 3m high dam will be certainly sufficient, the remaining risk one can cover with insurance. Drainage is necessary anyway. You have a lot of machines anyway. Machines to generate electricity are common in the Third World because electricity provided by the government regularly fails, so you can afford this too.
Last but not least, these are investments which have to be made by the 1% working in agriculture in modern industrial society. They will have the money. (Do you care about India? That 1 % who have the money would be happy to buy land in India which could no longer be used for agriculture because the local people cannot afford the investments. That's evil capitalism, combined with neo-colonialism, even worse, in the Chinese-communist form, of course, but the resulting food production will be nonetheless sufficient.)
Do you remember how rice fields in the mountains look like?
It is essentially the same technology, dams with appropriate drainage so that it works in the mountains too. Here, the water flows down by itself and has enough place to flow, so that you don't need pumps. But you need much more dams here. Nonetheless, this investment in dams has been done by people who are, from our point of view, very poor. Nonetheless, they easily survive your 150 mm per day rains, without even much loss for erosion because in most of this the speed of water is low, and where it is high, you have stones anyway.
