Water-based gels can be formed by a wide variety of substances. Agarose (from seaweed) will gel at concentrations as low as 0.2%, and some more obscure compounds can, allegedly, form gels at concentrations below 0.1%.
A few hundred tons of the dry compound, dumped in lines parallel to rivers, would form a self-setting flood barrier weighing several hundred thousand tons.
Alternatively, dumping the stuff into the upper reaches of the river might do interesting (and possibly helpful) things to its flow.
Cleanup might be an issue, post-flood, but inclusion of HFCS in the mix, coupled with the persistent industry of local ants, might resolve this problem.-- MaxwellBuchanan, Jan 17 2011 Wave wearing gel http://randomknowle...-wave-off-kanagawa/ [MaxwellBuchanan, Jan 17 2011] Ice Nine http://en.wikipedia.org/wiki/Ice-nineFictional water polymorph stable above room temperature [cowtamer, Jan 18 2011] Polymer sand bags http://www.nbcnews....p-young-f8C11371015 [scad mientist, Nov 25 2014] Jelly flood! https://www.youtube...watch?v=6jpogdvjKLYShaky documentary footage of this approach in action [Loris, Nov 26 2014] Jelly flood! Jelly flood! https://www.youtube...watch?v=gNiXf7Lejf0more - less shaky - footage from Ben and Holly [Loris, Nov 26 2014] Hmm. Given the notorious turbulence of floodwaters, we wouldn't even have to worry about stirring it, I think.-- gisho, Jan 17 2011 With some quite unreasonable luck, it might look like this <link>-- MaxwellBuchanan, Jan 17 2011 You missed an opportunity here - it should be custard! (Thick, gooey, not-very-flowy custard.) Other than that, I think it's actually a good idea.-- neutrinos_shadow, Jan 17 2011 The problem with custard is that you need quite a large mass of cornstarch to custefy a given amount of water.
Moreover, custard will creep, meaning that the flood is slowed, but not stopped.-- MaxwellBuchanan, Jan 17 2011 "custard will creep"
yay!-- DenholmRicshaw, Jan 17 2011 OK, jelly it is then. Funny that both useful substances are dessert foods...-- neutrinos_shadow, Jan 18 2011 Sounds like a gentler, kinder "Ice Nine" (see link -- halfbaked by Kurt Vonnegut, one of the greatest half-bakers of all time IMHO)-- cowtamer, Jan 18 2011 Fair enough [+]. Might you not end up with a huge, teetering pile of jelly?-- nineteenthly, Jan 18 2011 Well, a huge, teetering pile of jelly which melts slowly in the sunshine, releasing its water content over a few weeks is better than a sudden flash-flood. My only slight concern is that by creating a vast jelly dam, you may also create a vast artificial lake behind the dam. This lake might actually be on top of where some people live, which would be bad news for them. Also, jelly is not famed for its structural integrity and if the vast jelly dam were to rupture then it wouldn't just be the communities submerged in the lake which would suffer but also everyone downstream of the dam, who would be deluged by a massive tidal wave of water, jelly and the corpses of those drowned in the lake. Otherwise a fantastic idea.-- hippo, Jan 18 2011 I'm not saying i dislike the prospect of such a pile. I was mainly savouring the mental image. However, i had also thought of the possibility of a sudden dam burst.
If this was agar agar, if it could be rendered safe you could maybe use it to grow useful microorganisms.-- nineteenthly, Jan 18 2011 ...<film plot>which the handsome, yet flawed scientist would discover, while working late in his lab, was actually an evil micro-organism destined to cover the world in a 10-metre-thick layer of goo. Can he kill the micro-organism with the antidote before the goo covers his girlfriend's house?</film plot>-- hippo, Jan 18 2011 /dumping the stuff/ how scientific!-- po, Jan 18 2011 But what if cold weather caused the flattened circular or lozenge disc shapes to freeze? In order to prevent this, they should be pre-soaked in some sort of antifreeze solution, such as Sherry.-- hippo, Jan 18 2011 don't trifle with us.
thixotropic material doesn't have to be yellow.-- po, Jan 18 2011 Those super absorbant gels either rise or sink, and they have relatively low tensile strength especially as powder.
Basically you would get the front few hundred yards of the flood to be gooey and the rest would still wash away your house as normal.
Might be able to use them to say soak up a pond temporarily to do work-- metarinka, Jan 19 2011 // to say soak up a pond temporarily to do work//
That probably warrants a posting in its own right. Need to clean the pond? Lower some loops of rope into the pond, add gelling agent, allow to set. Lift out pond (complete with fish) using the rope loops, remove dead leaves and crud, replace pond, add gel-breaking agent.-- MaxwellBuchanan, Jan 19 2011 It reminds me of my idea to use old "disposable" nappies to protect Norfolk (UK) from the effects of rising sea levels, that I never posted.
Though I'm not sure I would like to be hit by flooding, followed by huge piles of old nappies that the emergency services had been saving in a national stockpile up just in case.-- VaquitaTim, Jan 19 2011 This would be a great way to prevent flooding from glaciers melting, as the previous poster alluded to.
A very large sponge (VLS) may be neater though, if one large enough could be constructed.-- phundug, Jan 19 2011 I envision this gel being deployed as "expandbags" - long fusiform bags of powder which expand on contact with water. They would occupy space and so could be used a part of a hasty wall. No doubt ordinary sandbags would be needed as well to weigh down the expandbags.-- bungston, Jan 19 2011 That's going to need to be some pretty tough gel.
I had just crossed a solid log bridge as a flooded river ripped it apart once. Got me a real good veiw of the force involved.Yep, pretty tough gel.-- 2 fries shy of a happy meal, Jan 19 2011 "long fusiform bags of powder which expand on contact with water"
Exactly. I just thought it would be a waste to use new nappies, when used ones are only half (or less) used on average. Loose tabs would help to bond the structure, but that might have to be specially organised with the previous users.
Might need to add quite a lot of HFCS to tempt the ants though.-- VaquitaTim, Jan 20 2011 Maybe mix the polymer with the sand?-- bungston, Jan 20 2011 Or you could use Simpson's Individual Emperor Stringettes.-- MaxwellBuchanan, Jan 20 2011 An 11 year old won $25k for reinventing (or recycling) your idea of using a polymer in sand bags. See link.-- scad mientist, Nov 25 2014 //An 11 year old won $25k for reinventing (or recycling) your idea of using a polymer in sand bags. See link//
Some spotty twerp got on the BBC for having the bright idea of using dirt cheap USB microscopes for cell motility. Something I did better 5 years ago. These things happen.-- bs0u0155, Nov 26 2014 I say anyone who can convert the incandescent genius put forth on the halfbakery into his or her own fun, profit and groupies deserves every bit of it.-- bungston, Nov 26 2014 Sandbags which are as light as water will wash away, so useless. Unless you want to backstop them with stakes driven deep into the ground (perhaps driven through the sandbags), in which case you'd probably want to start from scratch on the design anyways.-- FlyingToaster, Nov 26 2014 random, halfbakery