WAAHILA (TU1201)

[+Shorelander]

So my first knowing effort to recover one of the 1927 triangulation marks, WAAHILA (TU1201), took place on Wa'ahila Ridge near UH-Mānoa. I was excited by previous recoveries, and indeed found the Type C signal on the ridge:

 

 

However, my excitement proved short-lived as I looked at the 1969 recovery note from the C&GS:

 

THE STATION AND REFERENCE MARKS 1 AND 2 WERE RECOVERED AND FOUND IN GOOD CONDITION. THE STATION WAS PREVIOUSLY THE CENTER OF A 2-1/2 INCH IRON PIPE WHICH WAS PART OF A TYPE C HAWAII TERRITORIAL SURVEY SIGNAL. THE IRON PIPE WAS REMOVED AND A STANDARD DISK WAS SET IN THE CONCRETE PAD BY THE HAWAII STATE SURVEY OFFICE.

This is a very interesting statement because as far as I can tell, the iron pipe is still there! They may have meant the signal, which was welded to the pipe (per the Special Pub.), but why wouldn't they say that? Also, wouldn't that have meant they would have needed to have moved the original station in order to center the new disk appropriately? Not helping matters is the description of the station mark and RM1:

 

THE STATION MARK IS A STANDARD DISK STAMPED WAAHILA 1928 1969, SET IN A DRILL HOLE IN A TRIANGULAR SHAPED BEDROCK OUTCROP. IT IS ABOUT 3 FEET HIGHER IN ELEVATION THAN THE STATION MARK. REFERENCE MARK 1 IS A STANDARD DISK STAMPED WAAHILA NO 1 1928 1963. SET IN A DRILL HOLE IN A TRIANGULAR SHAPED BEDROCK OUTCROP. IT IS ABOUT 3 FEET HIGHER IN ELEVATION THAN THE STATION MARK.

Obviously the station is not 3 feet higher than the station. Given the differences in the heights of the station relative to the reference marks between the 1962 and 1969 descriptions, it would seem that they are describing a disk set in the concrete pad surrounding the old station. But I gave that pad a look and saw no such disk. The pad, as far as can tell (limitedly) has not been moved and is not moveable. Admittedly, I did not remove all dirt from the pad, so may have missed the disk. I do plan on returning to the station - it is not that strenuous or distant a location. But I was wondering what people here think. Is it possible they planned to remove the pipe and throw on a disk and didn't end up doing so? Or is it much more likely I need to really check that pad thoroughly?

Edited September 9, 2008 by Shorelander

[AZcachemeister]

Did you look down inside the pipe?

You may need a shop-vac, but maybe the disk is in there?

[+Shorelander]

I took a picture down the pipe, but you can't see the bottom:

But the pipe is considerably smaller around than a disk. How would they have monumented a disk down there?

[AZcachemeister]

Looks like the concrete was poured in '69, eh?

 

Easy.

Mount the disk in the rock (or whatever), set the pipe over the center of the disk and build the concrete monument around the pipe. A surveyor only needs access to the measured point on the disk, not the whole thing.

I have no idea if that's what they may have done, but that's what my instincts are telling me...

[+jwahl]

Well my interpretation is that the disk is on that small concrete platform that even shows a 1969 date, and then someone placed a new or reused the old tapered concrete thing over it. It looks sort of 'portable' and can probably be tipped aside, particularly if it had a long pipe in it.

[+Shorelander]

I was so decided that that was the original monument that when I was up there I didn't think it could date from the '60s. Of course, the date seems to have proven me wrong. So I went back up there today and did some more investigating. I tried my best to clean out the hole and got about an inch lower than the top of the pyramid, but I couldn't get any more dirt out with my tools. I brushed away the dirt from the base and it does look like new concrete was poured:

As you can see, that whiter concrete at the base of the pyramid and its slab is different from the rest of the slab. It looks like there is then newer concrete under the pyramid monumentation. I tried finagling it, but I had no luck. It didn't want to tip at all, and I really had no intention of trying to force anything for fear of breaking something. I didn't try pulling up on the pipe and concrete pyramid, but I don't think I could dead lift that.

 

So as far as I can tell, there's probably a disk set in concrete with this pyramid on top of it, which may or may not be moveable (or once was). I can't think of any way to dig out all the dirt from the pipe, given that there's probably two more feet beyond where I had to stop. I don't think I can move the pyramid, either, so I'm sort of stuck. Should I report this to the NGS? If so, how should I write it up? A NOT FOUND, I'd guess, with a description of current conditions? Does this warrant a POOR?

[AZcachemeister]

I guess it depends on how bad you want to recover this one.

It's described as a disk, and so far you haven't found one...at this time it's 'not found'.

 

I can think of three ways to clear out that pipe. Compressed air, water under pressure, or vacuum/suction.

Probably the simplest possibility (given the remote location) is to haul a car battery and a 12v vacuum cleaner up there and suck all the dirt/rocks/soil out of the pipe. I am assuming you have already found the RM and made sure it points to this monument!

 

Sometimes, all you can do is report what you did find, and move on.

[+Shorelander]

Hmm...I hadn't thought of compressed air. I wonder how effective blowing through a chain of straws might be. Alas, I have neither a car battery nor a vacuum cleaner, so that's not a viable option. I guess the solution is to report a NOT FOUND. Thanks!