Claim: Tulare Lake was once the largest freshwater body west of the Mississippi

Z.W. Wolf

Senior Member.
san-joaquin-valley-map.jpg



Due to heavy precipitation in California parts of the state are expected to experience serious flooding. In the San Joaquin Valley, a low lying area (now highly modified) that was once part of Tulare Lake is already flooding. That's true.

Here's where it gets bumpy. Recently, many news stories contain this sentence almost word for word: Tulare Lake was once the largest freshwater body west of the Mississippi.

This can be a true statement if the necessary qualification is added: Based on surface area.

I think that without this qualification this assertion is highly misleading bordering on dishonest - excused only by negligent ignorance. Is that an excuse?

In addition, I've seen the assertion that Tulare Lake was four times the size of Lake Tahoe.

https://www.nytimes.com/2023/04/03/us/california-tulare-lake.html#:~:text=Once the biggest body of,by the mid-20th century.
Once the biggest body of fresh water west of the Mississippi, Tulare Lake was four times the size of Lake Tahoe...

https://www.theguardian.com/us-news/2023/apr/06/tulare-lake-california-allensworth
Tulare Lake was once the largest freshwater body west of the Mississippi. In the mid-1800s, before canals diverted its water flow, the lake was a permanent feature of the San Joaquin Valley, covering nearly 800 square miles – about four times the size of Lake Tahoe.

Is this misleading? I think it is.

Stats for Tulare Lake when at high water in the 19th century. (Estimates from various sources.):
Maximum depth: 46 feet
Average depth: Between 30 and 40 feet
Volume: 6.5 million acre feet
Surface area: 790 square miles

And Lake Tahoe:
Maximum depth: 1,645 feet
Average depth: 1,000 feet
Volume: 122 million acre feet
Surface area: 191 square miles

Historic Tulare Lake four times larger than Lake Tahoe... Really?

It should be noted that Tulare Lake was part of a complex system of rivers, sloughs, marshes and terminal lakes, and water levels were seasonal and annual.

List of natural freshwater lakes in the U.S. west of the Mississippi larger than historic Tulare Lake by volume:
Lake TahoeCalifornia - Nevada122,160,280 acre⋅ft1
Lake Pend OreilleIdaho43,939,940 acre⋅ft
Lake ChelanWashington15,800,000 acre⋅ft
Flathead LakeMontana18,788,243 acre⋅ft

Crater Lake
Oregon14,100,000 acre⋅ft
Yellowstone LakeWyoming12,095,264 acre⋅ft

I'm leaving out Pyramid Lake at 23,660,000 acre⋅ft because it is 1/6 as salty as ocean water.

I'm also leaving out lakes in Alaska.
 
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I'm leaving out Pyramid Lake at 23,660,000 acre⋅ft because it is 1/6 as salty as ocean water.
Pyramid Lake is just the small remnant of ancient Lake Lahontan, which covered a huge portion of Nevada, but I can't tell you if it would have been fresh or salt water. Presumably a lot less salty than Pyramid lake is today.

That aside, I guess you'd have to define "bigger" for the sake of this comparison. I live near Lake Erie, which is not (quite) the smallest in area of the Great Lakes, but if you discuss volume it is by a wide margin the shallowest. Geographers and cartographers see the area; hydrologists see the volume. Trivia buffs see the depth, and Crater Lake is the deepest.
 
I don't see anything in your response as relevant to the discussion at hand.

The news stories are referring to Euro-American California times starting about 1860.

If you want to go prehistoric... Tulare Lake in the 19th century was a remnant of Lake Corcoran. But why talk about prehistoric lakes? How is that relevant?

And your response is full of the type of qualifiers that were left out of the news stories. My point is that leaving out the qualifier - based on surface area - is misleading or sloppy. Unwary readers are going to get the wrong impression. Four times the size of Lake Tahoe is a reckless claim at best.

I speculate these scenarios. The writers of such stories could have been:

- lazily copying other sources with no fact checking
- consciously exaggerating for the sake of drama
- consciously exaggerating for the sake of a political agenda; emphasizing the inherent greed and folly of the people involved in the destruction of this natural resource

One bit that might support sheer drama... The stories are emphasizing how quickly the old lake is coming back. Ignoring how shallow this basin is. Of course that also supports the "Mother Nature is the real boss, you silly humans" narrative.
 
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This can be a true statement if the necessary qualification is added: Based on surface area.

I just drove through there last week. As you pointed out, it's all in how one defines "biggest". It certainly had a large surface area 790 square miles, but not as much volume as the much deeper Tahoe.

As you also pointed out, it's not really a "lake" in the way Tahoe or Crater is. It's more of a big flood plain that can be lake-like in a wet year, and probably much dryer in a dry year.

The real question may be "what sounds better for headlines and clicks?"
 
How is 6.5 million acre feet four times the size of 122 million acre feet? This has a Flat Earth feel of intellectual dishonesty to it.

Considering the point that the lake was lost through the diversion of the rivers that once flowed into it... Obviously the volume of water lost is the important metric.

Considering the issue of flooding... The fact that the basin is shallow and that a large area of land may be quickly lost to a relatively small volume of water should be important.
 
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How is 6.5 million acre feet four times the size of 122 million acre feet? This has a Flat Earth feel of intellectual dishonesty to it.

Considering the point that the lake was lost through the diversion of the rivers that once flowed into it... Obviously the volume of water lost is the important metric.

Considering the issue of flooding... The fact that the basin is shallow and that a large area of land may be quickly lost to a relatively small volume of water should be important.
It's pretty obvious the four times claim is about surface area. Is this really important?
 
The story never mentioned surface area so how is that obvious from the news story?

Yes, it is important because I think it's poor journalism to ignore the important points I mentioned above. There should have been a complete discussion to illuminate those points. Volume is the important metric, and unwary readers are going to be tricked into thinking that Tulare Lake held four times as much water as Lake Tahoe. And that's best case scenario. Sloppy, poor reporting.

Worst case scenario: It's intellectually dishonest, with a Flat Earth/UFOlogy vibe to it.

Now this is just one case of sloppy or dishonest reporting. So what?

I'm not the one to harp on "Mainstream Media" but I don't like it when people who should feel responsible to their readers just bash out fluff pieces. Is flooding a trivial subject?

How much more trivial is this?: https://www.metabunk.org/threads/drone-photo-over-colorado-actually-a-boeing-737.11055/
 
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The story never mentioned surface area so how is that obvious from the news story?

Yes, it is important because I think it's poor journalism to ignore the important points I mentioned above. There should have been a complete discussion to illuminate those points. Volume is the important metric, and unwary readers are going to be tricked into thinking that Tulare Lake held four times as much water as Lake Tahoe. And that's best case scenario. Sloppy, poor reporting.

Worst case scenario: It's intellectually dishonest, with a Flat Earth/UFOlogy vibe to it.

Now this is just one case of sloppy or dishonest reporting. So what?

I'm not the one to harp on "Main Stream Media" but I don't like it when people who should feel responsible to their readers just bash out fluff pieces. Is flooding a trivial subject?

How much more trivial is this?: https://www.metabunk.org/threads/drone-photo-over-colorado-actually-a-boeing-737.11055/
Most people think of surface area when they think of lakes because it is what they can see and easily measure. Capacity is mostly important to people in agriculture.
 
I honestly don't know why you're making this argument. Best case scenario, the info as presented is ambiguous. Is that good writing?
 
you used quotes, not EX or article tags, so that content gets lost when I quote it
In addition, I've seen the assertion that Tulare Lake was four times the size of Lake Tahoe.

https://www.nytimes.com/2023/04/03/us/california-tulare-lake.html#:~:text=Once the biggest body of,by the mid-20th century.
External Quote:
After the barrage of atmospheric rivers that have swept through California over the past three months, Tulare Lake has not only reappeared, but it has also grown to cover 30 square miles — and could expand to 200 square miles in the coming months.
Obviously the author is referring to area.
External Quote:
covering nearly 800 square miles – about four times the size of Lake Tahoe.
obviously the author is referring to area
Is this misleading? I think it is.
I don't think so.

There are alternate ways to interpret the statement, but context makes it clear which one is correct.


Worst case scenario: It's intellectually dishonest, with a Flat Earth/UFOlogy vibe to it.
your complaint is disregarding the context, and that's a bunkish vibe for me
 
At the most casual level freshwater lakes usually are ranked by area rather than volume. You'll see Lake Superior get it's top billing without qualification all the time, and rarely even with qualification unless it's a scholarly source or a list that isn't ranked by surface area. On the other hand, Lake Baikal almost always gets depth or volume qualifications.

(Note: from here I'm skipping the Caspian Sea, which is undisputed in both areas and volume, but is disputed in status as a lake)

A big part of this is historical, because measurements of lake volumes have only solidified in the last few decades. We've had solid evidence Lake Superior is the largest lake by surface area dating back centuries. Aside from lakes unknown to European or Arab explorers and lakes that have actually changed in size the surface area rankings have been pretty consistent since the late 1700's.

Meanwhile we've only had accurate measure of Lake Baikal's top position by volume since the 1990's - surveys in the 1960's got a very similar maximum depth but lower total volume. At the time it's volume estimate put it second by volume behind contemporary measures of Lake Victoria. Victoria is another good example, it spent much of the 20th Century being called the largest lake in the world by volume and now it's eighth, not even top billing on its home continent, and even behind Lake Superior which it used to have the "well actually" advantage over.
 
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