# Flood Control - electrolysis - limit to rate of conversion?

Flood control - is it possible to use electrolysis to remove flood waters by converting water into oxygen and hydrogan gas? Is there a limit to the amount of water that can be converted at a time?

I know that this is a bit crazy and I respect what you are saying, BUT I am not trying to vaporize the entire Mississippi river, only enough to keep flood waters from ebbing into a house.

Maybe a different appreach - how about freezing the water place (in blocks) and then transporting it elsewhere

if only water was compressible....

• Sorry, but I'm afraid you don't know what you're talking about. That's like a least viable thing. Maybe even trying to drink it could be better. – Mithoron Oct 8 '16 at 23:20
• Well, it's rather late for changing ideas. You could write another question, but freezing isn't a good idea. Water is simply pumped out. – Mithoron Sep 14 '18 at 21:38

Floodwaters are immense in quantity. Let's estimate how much energy would be required to convert that quantity of water to $\ce{H2}$ and $\ce{O2}$.
1. The Mississipi river has a (non-flood) flow rate of about 593,000 cubic feet per second, or 17000 cubic meters per second. That's $1.7 \times 10^7$ liters per second, or $1.7 \times 10^{10}$ grams per second, or roughly $10^9$ moles per second.
2. Faraday's constant is the conversion factor between moles and Coulombs. It's value is about 96000 ampere-seconds per mol. Let's approximate it as $10^5$ ampere-seconds per mole.
4. Multiply the numbers together, and you get that to electrolyze all the waters of the Mississippi river, you'd need $4 \times 10^{14}$ amperes of current. That's about the amount of current present in a billion bolts of lightning. Yikes!
5. Exactly how much voltage would be required depends on your design of electrolytic cell you use for this giga-bolt scale. Let's say it's 5 volts. That means the power you need for the electrolysis is $2\times10^{15}$ watts. That's 2000 terawatts. But the world's current total energy consumption is about 12 terawatts...