Flood water use

Sam_Bass@lemmy.world to No Stupid Questions@lemmy.world – 42 points –

Has anyone ever given any thought to trying to capture all the floodwaters that seem to be increasing lately, and moving them to the more drought affected areas?

40

On top of the logistics of moving massive amounts of water around, flood water is typically highly contaminated - by their nature, floods sweep up everything in their path, which typically will include things like:

  • Soil and sand (a massive pain to filter out)
  • Agricultural run off (manure, pesticides, fertilizer, ...)
  • Raw sewage (from treatment plants that tend to be near waterways, or just from damaged infrastructure)
  • Industrial wastes (from existing plants, or old contaminated sites)

Infectious disease is a major problem after a flood, partly because of infrastructure damage but also just because so many people will have come in contact with contaminated water - you don't want to irrigate your crops with flood water, much less drink it

In California we have a project called Flood-MAR, which stands for Managed Aquifer Recharge. Farmers who have land that wont be damaged by floods volunteer to pump lots of water onto their lands during floods. This reduces the downstream flooding slightly, and the water soaks deep into the ground for safe keeping until it needs to be pumped up during a drought.

Seems like it would be a nightmare to purify. Perhaps useful for agricultural applications, but for drinking and household use…. Most water supplies don’t have e.g., human bodies floating in them.

Not a scientist, happy to be proven wrong here, but that’s my gut.

Not just bodies. When working around flood waters its recommended to wear hazmat gear because the water is contaminated by human waste from septic tanks, dead animals, petrol, oil, various poisons and fertilizers, chemicals from stuff like paint, etc.

Probably could be cleaned but even for agri use it would be crazy expensive.

I don't think you want to use dead body soup in ag either for the same reason using human waste as fertilizer isn't done.

Pretty sure there are existing methods of filtering such things out but i havent looked into it that deep(no pun intended)

If you filter the water through some sand, soil etc, it’s clean enough for many uses. There are systems that treat toilet water this way and then release the water into the environment. You just need lots of land in order to filter a small volume of water, so this method doesn’t really scale up very well.

I know its not really comparable, but seawater has almost as many pollutants in it and governments are actively researching desalination tech

As I understand, desal tech is available though it's prohibitively expensive, both in terms of acquisition and operations.

How would you move all that water? A fleet of water trucks carrying thousands of gallons (barely a dent)? A series of pipes across hundreds/thousands of miles? Who’s going to pay for it? And then you get into the problem of not actually knowing when/where a flood is going to hit. Yes, there’s flood zones, but a pipe route is going to be very specific, I doubt you could just pick it up and move it wherever. Maybe something would be done for a long-term problem to alleviate an already permanently flooded area, but it seems like such a massively expensive undertaking, I’m not sure anyone would be willing to do it.

Here's my half baked response.

They can pipeline oil over thousands of miles.

Why can't they pipeline water?

Oh shit. I think Nestlé heard me and all of our money goes to blowing up Palestinians, not giving drinkable water to Flint.

Disregard please.

Why can't they pipeline water?

Physically there's no issue. But oil goes from one specific spot (where it's located) to another specific spot (where it's refined). Floods and droughts are a little more random. So you're setting up massive infrastructure for sporadic use going from one random point to another. And all this doesn't generate money. Maybe it could save money, but bean counters don't care about that.

And there is my tidbit about blowing up Palestinians instead of ensuring Americans have potable water.

You can, they are called canals. Look at the Nile delta and the network of irrigation trenches used to spread water from the river to the wider areas. There are a number of dam projects in Africa which are all about managing water flows.

The principle problem is when your divert water it's usually at a cost to another area that was using it.

Yeah logistics would be a tall hill to climb, but onsite storage could maybe simplify it a bit. Like an under ground tank fed by things like storm drains?

Flood water is a terrible material.

It is full of sand, dirt, plants, animals (dead and alive), chemicals, germs of all kinds, body parts, dangerous pieces of junk...

Definitely not worth the effort. You want nothing else but to get away from it.

Moving? No. But apparently an early benefit of dams was to provide water throughout the year. Might see more of that.

Moving water is tricky. If you're lucky you can move it downhill, but I expect the situations where you can do that from flood to drought is not common. Moving uphill is pretty much out because it'll take too much energy.

Some cities catch flood water, hold it, and release it to reservoirs, rivers, etc. later. Chicago's is interesting and Dallas has a GIANT water vault under Central Expressway. I think most of our water comes from dead (animal) soup.

If the price is right water can be delivered anywhere. Conveniently, places that suffer from droughts also sometimes suffer from floods, so it can just be saved for later rather than delivered anywhere.

Build an aqueduct!

A thousand mile acqueduct would be less feasable than a giant underground storage tank

a giant underground storage tank

That's basically what groundwater is already.

The trick isn't storing it. The earth does that naturally. The trick is moving it where there isn't enough.

Perfect idea. Let's drop a huge pipeline from the Mississippi all the way through to California. The energy to build the pipeline, and run the pumping stations will certainly not add to the already problematic energy causing climate change causing these droughts that we're "fixing" with this huge pipeline.

/s

How much water would a super collider tunnel hold?

The Large Hadron Collider is 27.4 km in circumference and the tunnel is 3.8 metres wide.

So roughly 27400m x 11.34m^2= 310,716m^3

An Olympic sized swimming pool is 2,500 m^3 so it would be just under 125 of those.

From an individual standpoint thats a lotta watta

The Mississippi River average flow rate is 21,749.5 m3/s so that’s like fourteen seconds of flow.

Fourteen seconds is also my record for sex.

Usually takes me a couple minutes but maybe thats just age. Any amount that a flood could be reduced would doubtless be appreciated

From a multinational consortium standpoint, that's small enough to ignore.