Does This Mark Have A Name?

[Wintertime]

I'm organizing my photos and notes from a bunch of benchmarks I found near Yosemite last month. There are some at the spillway of the Moccasin powerhouse of the Hetch Hetchy water system. (If you get that way, also be sure to check out a cache that Retired-ee and I created called "Hetch Hetchy-Moccasin"!)

 

Anyway, there are two benchmarks on one buttress of the spillway. One of the marks is HS0945. Here's a photo of it:

 

 

About 10 feet away is this mark:

 

 

And just to help you visualize everything, here's a photo of both (HS0945 on the left):

 

 

My question is, is the second mark called "LINE"? Or "DAM MOM LINE"? (What would "mom line" even mean?) I want to mention it when I log HS0945 on Geocaching.com, and I want to refer to it appropriately.

 

Thanks!

Patty

[Wintertime]

Bumping this up to see whether anyone can help with the name of the second benchmark.

 

TIA,

Patty

[ArtMan]

Wintertime,

 

A station disk stamping often (but not always) reflects the name (technically called the "designation") of the mark.

 

Suggest you enter the coordinates (hope you have them; otherwise, you'll have to estimate from a map or other source), and see if you get any hits at your location.

 

Keep in mind that there are probably millions (literally) of those disks out there that are NOT in the geocaching.com database (which itself is a snapshot of the National Geodetic Survey data from several years ago).

 

It appears these disks were set by the San Francisco Hetch Hetchy Water System, and if you want to pursue it you might get in touch with that agency, possibly their engineering department, for further info.

 

Good luck!

 

-ArtMan-

[Wintertime]

Hi, Artman.

 

Oh, no, I'm not trying to find the mark in any database. I already know it isn't in NGS's database. I just want to mention it in a report about HS0945 that I'm filing with the USGS, and am wondering what the proper way would be to refer to it. I could try contacting the SFPUC, but I was hoping that a surveyor could tell by looking at it what one would call it. I'll just go with "LINE" if no one has any better idea.

 

Patty

[evenfall]

Hi Patty,

 

The Hetch Hetchy sure is a Controversial Water system. Hooo Boy!

 

There is very little specifically about the Moccasin Reservoir online to research. Hard data? Zero.

 

My Best educated guess from looking at stations in the area is that it may be a Line Only Station meant for helping an instrument look in a specific direction and see a specific thing. What "MOM" means is anyones guess.

 

Did you catch HS0944 on the other side of the Dam?

 

Good Luck,

 

Rob

[ArtMan]

I just want to mention it in a report about HS0945 that I'm filing with the USGS, and am wondering what the proper way would be to refer to it.

Patty,

 

In that case, I would refer to everything stamped on the disk, rather than make an educated guess. I would also include the coordinates from your GPS (and specify that they were obtained from a handheld, consumer-grade model, not a professional-grade unit), and a narrative description of the location.

 

Good luck.

 

-ArtMan-

[CallawayMT]

What about "Montitoring Observation Monument"?

 

CallawayMT

[Wintertime]

The Hetch Hetchy sure is a Controversial Water system.  Hooo Boy! 

Oh, yeah..... :-) Legend has it that the authorization of the dam drove John Muir to his grave. That's a bit of an exaggeration, but he did die only a year after the Raker Act was signed by President Wilson.

 

There is very little specifically about the Moccasin Reservoir online to research.

If you mean about their surveying, yeah, nothing on that that I know of. But you can see more HH history on my "Hetch Hetchy - Moccasin" cache page and on the SFPUC's website.

 

My Best educated guess from looking at stations in the area is that it may be a Line Only Station meant for helping an instrument look in a specific direction and see a specific thing.

Ah, okay.

 

Did you catch HS0944 on the other side of the Dam? 

Yep. There's also supposed to be on somewhere along the street that runs along the eastern side of the reservoir, but we couldn't find that one.

 

  I would refer to everything stamped on the disk, rather than make an educated guess. I would also include the coordinates from your GPS (and specify that they were obtained from a handheld, consumer-grade model, not a professional-grade unit), and a narrative description of the location.

Yeah, good idea about putting the full stamping in my notes. I'm also annotating that photo with the two circles; I'll just call it "LINE" there. And yes, my reports include the coordinates of everything I've found. The guy I'm sending them to knows that I'm just an amateur, but maybe I'll put a note in the Word file, too, in case anyone else ever reads it.

 

What about "Montitoring Observation Monument"?

Is that really what it means? Or are you just making an educated guess? ;-)

 

Thanks, all!

 

Patty

[evenfall]

Patty,

 

I spent a couple hours pouring over what I could find and what I found was the creation of the Sierra Club... It was an interesting read and a humongous public works project for its time... It looks like the whole area is looking at renovation soon and perhaps removal of the original reservoir, but one wonders if it will al really work out in the end. One of those issues where there are two sides to it and always will be. Hetch Hetchy is quite a story.

 

If we may venture further guesses without regard to education, Imagine this.

 

Say you wanted to monitor the stability of a dam. You know, with a monitoring observation monument. Who knows what the MOM means really but if you were going to keep watch on the dam, you would want your instrument set up at the same place every time and you would want to look at specific places to see if you can measure a change.

 

So it isn't that far fetched.

 

In construction staking, I place line only markers all the time. This helps the constructor get both line and grade from the survey marker, this way they can position the work to the correct position and elevation the design calls for.

 

With two stations so close on that wing wall, it seems feasible they could set an instrument up and have it be positioned so it could look at something specific... Who knows. Maybe not... Dam Stability is a good thing to keep track of.

 

At best, an inquiry to the SFPUC about the survey data at the Dam site may leave you with more clues. Hope that helps.

[Wintertime]

Yeah, that mark at the end of the buttress might well help them keep track of how the spillway is doing. It looks right out over the reservoir.

 

Sounds like you already found the Sierra Club's Hetch Hetchy history page:

 

http://www.sierraclub.org/ca/hetchhetchy/history.asp

 

There's more info on the SFPUC's history site:

 

http://sfwater.org/main.cfm/MC_ID/5/MSC_ID/37

 

(start by reading the section on the Raker Act), and on the Restore Hetch Hetchy organization's site:

 

http://www.hetchhetchy.org/

 

I've written to my contact at Moccasin to see whether she knows anyone who might be able to provide me with more information about the survey marks there. There are also a bunch of marks along the aqueduct that I'm sure are on fenced-off SFPUC land, but maybe there are also some publicly accessible ones I haven't found yet, including the one my friend and I looked for unsuccessfully in the town of Moccasin.

 

Patty