Deep Water Benchmarks

[2oldfarts (the rockhounders)]

We were looking for some old benchmark listings in GSAK (for the upcoming contest) and noticed some of the marks in our area are deeply submerged in Lake Powell. By deep I'm referring to 400' to 500' or more.

 

The question is would these be candidates for being considered destroyed? Granted, you can not actually verify that the disk is there, but there is no way it will ever be accessible. It is possible to verify the lake level though and compare it to the recorded elevation for these marks.

 

HN0374

HN0375

 

 

John

 

 

edited to add the links.

Edited February 27, 2006 by 2oldfarts (the rockhounders)

[Bill93]

My vote is that difficult to access does not equal destroyed. Maybe in some future century a natural disaster will drain the lake and scientists will want to know how much the lake bed has moved.

[mloser]

Don't forget unnatural disasters, or even planned removal of the dam. All over the country there are studies being undertaken to ascertain the environmental impact of dams and whether there is a strong case to remove them.

A quick search of the Internet turned up this article and a page by American Rivers that lists recent dam removals. And finally, a well written article in the BioBulletin about dams and their futures.

So those marks may reappear again someday!

[+seventhings]

I would log such marks as NOTE, with comment that I could not search for the mark because it's described location appears to be inaccessible because it's way under water, etc.

 

Were I to submit a recovery report to the NGS, I would report NOT FOUND with comments as to the reason why.

 

W

[+Cyclometh]

Hmm. Can you get SCUBA equipment that lets you dive that far?

 

Logging a "found" on those would be a feather and a half for your cap!

[2oldfarts (the rockhounders)]

Hmm. Can you get SCUBA equipment that lets you dive that far?

 

Logging a "found" on those would be a feather and a half for your cap!

 

 

Estimated depth currently is 450' - 500'. I don't think scuba will help and the amount of silt and sand blown into the lake since about 1960 will have buried the marks, anyway.

 

John

[+Cyclometh]

Hmm. Can you get SCUBA equipment that lets you dive that far?

 

Logging a "found" on those would be a feather and a half for your cap!

 

 

Estimated depth currently is 450' - 500'. I don't think scuba will help and the amount of silt and sand blown into the lake since about 1960 will have buried the marks, anyway.

 

John

 

I did some research, and a rebreather (heliox was mentioned) could get you that depth. But it would require months or years of training and experience to safely dive that deep. It'd take a support team, and you would likely not have a huge amount of time to search.

 

It'd still be a hell of an accomplishment! Would that be a found poor or just a found as described?

[+Adrenalynn]

Hmm. Can you get SCUBA equipment that lets you dive that far?

 

Logging a "found" on those would be a feather and a half for your cap!

 

 

Estimated depth currently is 450' - 500'. I don't think scuba will help and the amount of silt and sand blown into the lake since about 1960 will have buried the marks, anyway.

 

John

 

I did some research, and a rebreather (heliox was mentioned) could get you that depth. But it would require months or years of training and experience to safely dive that deep. It'd take a support team, and you would likely not have a huge amount of time to search.

 

It'd still be a hell of an accomplishment! Would that be a found poor or just a found as described?

 

Rebreather would not be the way to go. Rare-gas diving, yes. But as you mention, a heck of an undertaking. Back when I was doing the scuba thing pretty seriously, I did a confirmed 350ft dive. Your bottom time is nothing, and the decomp time is immense. So the upshot is - no, not practical.

 

That said - those could be *easily* recovered with RPV submersibles. Even a "hobbiest" deep water RPV would pick those off. Even if they're under feet of silt, they can be blown and vacuumed. Treasure hunters do it "all the time".