Below The Pavement?

[Railfan]

Hello all,

 

I went looking for my first benchmark yesterday on my way home from work. Its location is just over a mile from my house so I thought it would be an easy one to start with. Unfortunately I didn't have more than a few minutes to spend on the site, but I was at the right location and found what I think to be one of the reference marks listed in the description. However, I'm confused about a few things.

 

The description states the following (emphasis mine):

IT IS A STANDARD DISK STAMPED PAWTUXET 2 1956 SET IN A DRILL HOLE IN THE TOP OF A BOULDER APPROXIMATELY 1 FOOT BELOW THE LEVEL OF THE MACADAM PAVEMENT AROUND THE CLUB HOUSE.

Does this mean that the disk is actually below the pavement, or does it mean that its location in relation to the level of pavement is 1 foot lower?

 

The reference mark that (I thought) I found is described as:

REFERENCE MARK 3 IS A STANDARD DISK STAMPED PAWTUXET 2 NO 3 1956 SET IN A DRILL HOLE IN THE TOP OF THE CONCRETE CURBING AROUND THE PAVED PARKING AREA. IT IS IN THE SOUTHEAST CORNER OF THE CURBING, 12.0 FT. SOUTHEAST OF THE SOUTHEAST COLUMN SUPPORTING THE CLUB HOUSE AND 5.0 FT. NORTHWEST OF THE MHWL.

The actual mark that I found was not stamped Pawtuxet 2 No 3 1956, but it was located in what I believe to be the exact spot described. Here is a photo:

 

 

If anyone can provide this newbie with some information, it would appreciated!

Edited August 5, 2004 by Railfan

[+planetrobert]

i, from a little experience will say that it means it is lower in elevation that the pavement, but not under it.

 

kinda a vertical refrence for you to use.

[+seventhings]

Railfan -

 

I agree with ralann. If the mark was really below the pavement, the wording would be something like "... 1.0 feet below the surface ..." But, I have seen enough variation in the words used to describe marks and their locations so as to not rule out that the mark is really below the pavement.

 

Since your mark, LW2723, has ADJUSTED coordinates (very precise), your GPs' GOTO function should get you to within a few feet of the mark (assuming a clear sky and several approaches from 40 feet or so away and from different directions). If your GPS consistently takes you to a point on the paved surface, it is likely that the disk is buried. If the GPS consistently takes you to a point beyond the edge of the paved surface, that's where your station is likely to be.

 

I don't think that the station is buried.

 

The disk in the photo is a TIDAL STATION DISK. These are very common around coastlines and the banks of major rivers. Often, they have their own PID and are in the NGS and Geocaching databases. A search of the "nearest benchmarks" to LW2723 yields no Tidal stations nearby. Also, I did a radial search in the NGS database (based on LW2723's coords) and came up empty there as well. So, I think that the disk in the photo is (1) a tidal station that does not have a PID, and, (2) not a RM for LW2723. This is consistent with the description of the RMs on LW2723's datasheet.

 

If I were you, I would go back to LW2723's location and give my handheld several opportunities to take me (very close) to the station. I would also take my tape measure and use it to measure out an arc, with a radius of 16.2 feet, from due NORTH to due EAST from the described column, and then search very carefully along that arc (especially if the GPS suggests that you are very close to the mark's coords when you are 16 feet or so NE of the column). The combination of the GPS and the tape should get you to within a few feet of the mark and confirm that it is not under the pavement.

 

will

 

ADDED: another thing to consider - station LW2723 was monumented in 1956, and there have been no recovery updates since then (confirmed on the NGS site). The NOAA Tidal station you found was set in 1977. It may very well be that LW2723 was destroyed/paved over sometime in the past 48 years (perhaps, when the yacht club was remodeled/expanded/re-landscaped), and the tidal station was set in response to the loss of Pawtuxet 2.

 

Or, put another way, given what I see in the description (I am not familiar with the area), Pawtuxet should be easy to find or it could be impossible to find.

 

Such is the nature of benchmark hunting. Yours is a familiar kind of case.

7

Edited August 5, 2004 by seventhings

[+ddnutzy]

With all the reference marks in the discription one of them should have a arrow pointing to the station. Use the measurements and bearings in the discription to establish the rm's and line up the direction the arrows point. Where two or more of the line of the arrows cross, that is where the station should be.

[+Desert_Warrior]

Very often, "Below The Pavement" means it is in a hole woth a cover cap over it. Take a look at THIS ONE to see an example.

 

It may be right there! Good luck.

[Railfan]

Thanks for the info everyone. I'll be heading back to the site this weekend for another look. I'll post an update shortly thereafter.

[+Black Dog Trackers]

Railfan -

 

Before you go, be sure to click on "view original datasheet" on the benchmark's page. In the original datasheet you will find the distance and azimuth (true north based, not magnetic) to reference marks 3 and 4. In case you can find either reference mark, bring a tape measure and the conversion factor between meters and feet.

 

I am 95% certain that the phrase "APPROXIMATELY 1 FOOT BELOW THE LEVEL OF THE MACADAM PAVEMENT" means that the disk was not under the pavement in 1956, but was instead somewhere near the edge of the pavement but below its level. The scenario would be a disk on top of a boulder, and the entire boulder is away from and below the level of the pavement, probably in a ditch or down a slope from the pavement.

 

I don't know what MHWL is.

 

If the pavement and curbing looks newer than 1956, your disk is probably going to be a no-find.

[+Renegade Knight]

Ever wonder why a lot of interesections have a hole in them dead center? That's a benchmark. it may not be listed on GC.com but at least in my neck of the woods they can and do get buried in the asphalt and they do get dug up with the survey equivilent of a jackhammer.

[Z15]

In this case the words

APPROXIMATELY 1 FOOT BELOW THE LEVEL

OF THE MACADAM PAVEMENT

means the mark is 1 ft difference in elevation than the pavement, not that its buried beneath it.

[+seventhings]

BDT -

 

I think MHWL is Mean High-Water Line.

 

will

[Railfan]

I think MHWL is Mean High-Water Line.

Yes, that is the meaning of MHWL. That much I'm certain of!

 

Regards,

Rich

[Bill93]

I would agree that the mark is not under the paving that is referred to. But it very well could be underground or under newer paving.

 

It might even have been intentionally buried. This is a horizontal control station. In my area nearly all of the horizontal stations (triangulation stations) set in the 1930's to 1950's are buried.

 

They have a "surface mark" typically 18 inches down in soil (not too many rocks available here) and the true mark about 4 feet lower. They are a disk in a concrete post sitting on top of another disk in a post with careful alignment to keep one precisely over the other. When you look for them, you only find the reference marks. If you can't see the (buried) surface mark you can't log a find on GC.com.

 

Bill93