USGS
Survey Marker
The USGS Survey Marker is a P-K nail and washer for
running levels; flagging high watermarks; establishing
bench marks, reference marks, and reference points at
stream-gaging stations; and in reconnaissances of new
sites, etc. It is a common practice in the USGS to use
common nails and surveyor-nails (referred to as PK nails)
to flag high watermarks and to establish reference marks,
reference points, and bench marks. It is often found that
the nails can be confused with nails set by landowners or
land surveyors working around USGS sites. This confusion
can lead to errors in levels and high watermark elevations
if the wrong nails are used.
The USGS nail eliminates the guesswork as to which nail
was set by the USGS as opposed to nails set by state and
county engineering crews, utility companies, contractors,
and land surveyors. Other features include:
- Easily visible when set in a tree, telephone pole or
cement bridge wall.
- Does not bend as easily as a common nail and doesn't
rust.
- Can be easily set in concrete using cordless hammer
drill. A surveyor-nail protruding from a cement wall is
much more visible than the chiseled marks the USGS
normally sets on a concrete bridge for a reference
point.
- Can be distinguished from nails set by someone other
than the USGS, thus helping to eliminate the error of
choosing the wrong nail if multiple nails are set in the
same vicinity as the USGS nail.
- Can be custom produced with your agency's mark such
as "ODNR Survey Marker"
905-001
USGS Nail and Washer (set of 10)
0.3 lb.
Brass Gaging Station Tablet
Brass Flood Mark Tablet
The USGS sets elevation datums at gaging stations for
permanent accurate stage measurement reference. Each
station is required to have three known elevation markers
so elevations can be checked periodically.
Flow depths are equivalent to the differences in
elevations of the water surface and the lowest point of
control over which the water can flow. Elevation of zero
head through the control is referred to as gage datum
elevation (GDE).
A permanent bench mark (BM) should be established for
convenient use in checking and maintaining the proper
relationship between the GDE and the water level recorder
or gage.
The gaging station benchmark tablet is a brass disk 3
5/8 inches in diameter constructed with a 1/2 inch OD by 3
inch long brass tubing shank to enable the tablet to be
set in concrete.
The Floodmark benchmark tablet is a brass disk 3 5/8
inches in diameter, constructed with a 1/2 inch OD by 3
inch long brass tubing shank to enable the tablet to be
set in concrete. The tablet is normally mounted on the
horizontal plane; however, it may be mounted on a vertical
plane if desired.
905-010
Gaging Station Tablet
0.3 lb.
905-011
Flood Mark Tablet
0.3 lb.
905-012
Custom Marked Tablet 0.3 lb.
Plastic Flood Mark
Indicator
Plastic floodmark disks 1 1/2 inches in diameter by
1/16 inch thick with a 5/32 inch diameter hole in the
center are available in three colors: green, red, and
white. They are intended as a temporary mark that can be
nailed to trees, utility poles, or other structures to
mark a high waterline.
905-020
Floodmark Disk, green, pkg 50
0.4 lb.
905-021
Floodmark Disk, red, pkg 50
0.4 lb.
905-022
Floodmark Disk, white, pkg 50
0.4 lb.
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