How great of a lake could a billionaire have made in the U.S.?

What would the limits be for a multi-billionaire who wanted to make a fantastically huge and clean and clearish man-made lake for a fishing and wildlife refuge (no motorized craft)? There could be a hydroelectric damn to offset costs, but he’d still have to acquire land, clear it, and excavate (to get a sand, gravel, or rock bottom). How great can he go, and how awesome would that be?

What do you consider the limiting factors?

If you’re saying he’s got an unlimited amount of money then costs don’t matter. Otherwise you’d have to give us some more financial details.

There some maximum area to the US, and a minimum amount of terra firma needed to hold fresh water in a lake, so that’s the outside extreme sizewise.

There’s also a limited amount of freshwater available in the world. An almost US size lake would need more than that, and it would take a long, long time to desalinate that much water. And the bigger the lake gets, the more rapidly it loses water by evaporation, so you’d need a steady source of fresh water to keep it from drying up.

Are you asking how awesome it would be to do it? Well pretty awesome. To maximize awesomeness you don’t want the greatest surface area, you want the longest shoreline. So you’d want a long narrow lake, no more than a few miles across. And if you don’t allow motorized craft you’d really cut back on the awesomeness. You want beaches and boats. There’ll be plenty of room in the middle for fishermen and divers.

The easiest way to do this would be to dam the lower end of the Mississippi and build up the lake side to cut the flow of water through the gaps in the Rockies and Appalachians. It would be huge. Kind of expensive though. A lot of nutjobs would object for some reason or another, so in addition to the land and construction costs you’d need to spend a fortune on congressmen and senators.

Water rights are controlled by extensive legislation and interstate compacts. You’d have to overturn lots of laws to impound that much water.

I agree with TriPolar… This is a question with too many variables to answer properly.

However, if he wanted to fill up a big hole? There are a few large mines around the world that are pretty deep and wide. He could also buy the land in Arizona where that meteor struck. If he filled that crater it would be a pretty cool swimming pool.

First blush is how many square miles of land in the middle of nowhere will a billion dollars say buy? It will be big, but it ain’t gonna be great lakes big I suspect.

Pretty sure the state of California would sell him the Salton Sea. He could go from there.

Yes, excellent question.

I know there’s too many variables, so I put it in IMHO for wild ass speculation. Let’s say Bill Gates, he’s willing to sink half his fortune into it, and it has to be in the U.S. - anywhere but Hawaii and Rhode Island (too small).

I have no answer. I merely wish to register my appreciation of the combination of the OP’s user name and the topic.

Well, if we go with a thousand dollars an acre, a billion dollars will buy you about 1500 square miles of land. Or a square a bit under 40 miles on a side. Pretty big lake but not OMG big.

Lake Michigan is already 22,300 sq. mi. He could just buy that instead of making a new one.

If I’m a billionaire, I’m going to fill a swimming pool with money and dive into it like Scrooge McDuck, not fill a lake with regular old water.

Why not just buy the grand canyon, and fill it to the top?

Under Minnesota statute, once you hit 2 square miles (1280 acres), it would become Public Waters. With all the other conditions, it’d probably take a lot less.

Damn squareheads gunning for their 10,001 lakes.

Water rights would prevent anything too huge. You have to divert the water from somewhere to fill your billionaires reservoir.

1280 acres would be a huge private lake fit for any billionaire. That’s probably the limit in most states. Even getting that much water rights would take political clout.

Poland Spring?

I checked and Lake Oahe is the largest Man Made lake in U.S. (685 sq mi).

I find it hard to imagine building a lake even a fraction of that size without eminent domain, but the King Ranch is Texas is 1,300 square miles

Only marginally on subject, but the Stuart Woods book Under The Lake describes a billionaire “building” a lake. Basically he buys all (well, most) of the land in a long, narrow valley, builds a dam and fills the valley with a lake. I imagine with enough political clout there are places in the US that someone could actually do this.

The limits here are going to be legal and political more than financial or technical. Water is an increasingly valuable resource these days. By creating a giant lake with a clay retention layer you are effectively diverting and preventing the water from percolating back down into the existing underground aquifers that many people and municipalities rely on, or running off into streams and rivers.

There’s a point at which your huge lake will negatively impact a lot of water users not directly on your property. The billionaire’s lake plan will run into a legal and political buzzsaw once it gets beyond a moderate size.
So… no mega-lake for you moneybags.