Lake Manly arithmetic...

[GowerGulch42]

I was pondering today how long Lake Manly would last in today's climate, so I did some reading and arithmetic.

Many publications cite Lake Manly's depth at about 600 feet, but the highest known shorelines actually suggest a max depth of about 1100 feet (335 meters)! This is called the Blackwelder Stand, and is one of the oldest high shorelines of Lake Manly. A 2004 report by the USGS showed that the average evaporation rate of Death Valley is 150 inches/year, and an average of 1.9 inches of rain per year. That's quite a deficit. Let's be conservative and say that there's 145 inches of evaporation per year. If Lake Manley was 1100 feet deep at its deepest, then that means Lake Manley would evaporate today in…

91 years.

Clearly, there's some nuance there with how the lake itself would reduce evaporation by being a heat sink and creating local humidity etc etc…. but I think it's a good demonstration of how dramatically the climate needed to shift over a few thousand years for that to happen! We think that the lake completely disappeared a few times before the modern day, but it was about 30 feet deep for a while about 2,000 years ago, and there are numerous ancient habitation sites along the shores of that particular lake stand.

Anyway, I thought that was neat.

[MojaveGeek]

I can only imagine how different it would feel with a 30 foot lake, presumably with rushes and other water plants and likely some mesquite and other trees too, if the water table was stable.

[David_Bricker]

Also remember that even though there is 1.9 inches of rain a year, there is some, albeit not a lot usually, water that flows into the basin from the Amargosa River.  I've seen the river high enough, at the bottom of West Side rd, that crossing it in my lifted 4wd Jeep would have been ill advised.

So, it might be even longer than 91 years.

David Bricker / SYR

[GowerGulch42]

Yes, of course. But there isn't water flowing in from the Amaragosa River 99% of the time. I think it's fairly safe to say that it wouldn't last 150 years in today's climate.

[DeathValleyDazed]

Clearly, there's some nuance there with how the lake itself would reduce evaporation by being a heat sink and creating local humidity etc etc…. but I think it's a good demonstration of how dramatically the climate needed to shift over a few thousand years for that to happen! We think that the lake completely disappeared a few times before the modern day, but it was about 30 feet deep for a while about 2,000 years ago, and there are numerous ancient habitation sites along the shores of that particular lake stand.

Thanks for the provocative thread. Any way of calculating the salinity curve to coincide with the evaporation rate? 

In the meantime I'll keep an eye our for those 30 feet depth shoreline inhabitation sites during my future stumbling about the area. If I set up a long term campsite and tent in just the right spot I'd have Lake Manlyfront property.