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Details for Benchmark: KU3532

N 40° 40.345 W 073° 58.041 (NAD 83)

Altitude: 128

Coordinates may not be exact. Altitude is SCALED and location is ADJUSTED. (more info)

Location:
In KINGS county, NY View Original Datasheet
Designation:
PROSPECT WATER TOWER 1903
Marker Type:
bolt
Setting:
setting not listed - see description
Stability:
Mark of questionable or unknown stability.

Must Read!

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A bunch of neat history was lost since this one has been DESTROYED back to 1932.

Excerpt from the now 'non-published" DS. Check 'Include Destroyed Marks' on the PID entry page to retrieve a truncated version of what is in the Geocache file.

KU3532 HISTORY - Date Condition Report By
KU3532 HISTORY - 1903 FIRST OBSERVED CGS
KU3532 HISTORY - 1932 DESTROYED CGS
KU3532

[b]Historical Note:[/b]

Not only is there an interesting benchmark history at this station, but there is more interesting benchmark history right across the street.

In 1909, the New York City Board of Estimate and Apportionment (abbreviated NYBE+A) commisioned a survey of all five boroughs of New York City. This was the first city-wide survey to be done after the consolidation of the five boroughs into the City of New York in 1898. The survey would replace numerous incompatible systems in use by many city agencies, such as the highway department, the water department, the Department of Docks, etc. There were over 1000 benchmaks set in all, and the marks in Brooklyn go from #178 (at Fort Hamilton) to #504 (at the bulkhead on Newtown Creek at Manhattan Avenue, across from Queens), or 327 marks in all for Brooklyn. Of these, just 23 (that I know of) were put into the NGS database in 1952. You can tell if you get one of these Brooklyn marks if the designation is a number between 178 and 504.

The whole project and descriptions of each mark can be found in the volume [i]Precise Leveling in New York City[/i] by Frederick W. Koop, published in 1914 and available in the New York Public Library. Mr. Koop was head of the surveying team that set the marks.

A number of these historic marks are lost, but many are still around if you just know where to look. Three of the bench marks from this original 1909 survey survive just across Flatbush Avenue from this station. Two (#381, a disk, and #382, a chiseled cross) are on the arch (the Soldiers and Sailors Monument) in the center of the Plaza and the third (#387, a copper bolt) is on the step of the round granite structure directly across the street.

#381 is particularly noteworthy. It is a 2 inch brass disk inscribed "BD. OF EST. & AP.". There were less than 20 of these disks used and this one is in the best condition of any I have found. These are the only bench marks used that are what we would immediatly recognize as a "Bench Mark Disk".

I have included pictures and directions to these marks. They're not in the NGS database, so if you find them, you get "extra credit" or you can waymark them. Have fun!

[b]Pictures:[/b] All the pictures and directions are attached to my note for [url=http://www.geocaching.com/mark/log.aspx?LUID=94d008ff-c211-42d5-b230-584b8b1e2226]KU1296[/url] (the bench mark on the Library - which you should also recover if you haven't already).

[This entry was edited by Papa-Bear-NYC on Thursday, March 23, 2006 at 1:39:04 PM.]

Found as described in good condition.

This station has a long and interesting history and I highly reccomend you read the datasheet in full. In short, the old water tower (now gone) served as the origin of the Brooklyn coordinate system which defined street locations for the entire borough and it also served as one of the primary triangulation stations for the 1903 triangulation of New York City. Although the tower is now gone, I have included a diagram from the original report showing the layout of the tower and the triangulation point under the apex, together with various bearing lines to other stations (see last photo). The report was entitled [i]Report on the Triangulation of Greater New York by the Cooperation of the City of New York and the United States Coast and Geodetic Surver, Executed 1903 to 1908[/i], published in 1914, and available in the New York Public Library.

The current monument marks the exact location of the tower, although it has undergone 4 incarnations if I counted right. The actualy triangulation point is the chiseld cross, not the hole. The hole was the triangulation point for a previous incarnation.

To find it, go past the Library on Eastern Parkway and enter Mount Prospect Park (not to be confused with Prospect Park) and when you get to the top of the stairs, look for the granite hexagonal monument off to the right, just past the end of a chain link fence. See the photos.

If this weren't interesting enough, there's another twist. There is is a vertical control station (bench mark) which was surveyed to use the same monument as this station. It "piggy backs" on the monument for this station so-to-speak.

That station ([url=http://www.geocaching.com/mark/details.aspx?PID=ku1297]KU1297[/url], "22"), as far as I can tell, was surveyed in 1952, long after the tower was gone, and uses this station's monument (which marks the tower location).

[This entry was edited by Papa-Bear-NYC on Friday, February 17, 2006 at 5:40:46 AM.]

[Photos:]
photoKU3532, Prospect Water Tower, Brooklyn NY
The entrance to Mount Prospect Park, just past the Library on Eastern Parkway.
photoKU3532, Prospect Water Tower, Brooklyn NY
View from the top of the stairs. The monument is off to the right (outlined with a yellow oval) just to the right of the end of a chain link fence (seen edge-on in this view).
photoKU3532, Prospect Water Tower, Brooklyn NY
The granite monument with the copper bolt. A brass plate was originally mounted around the bolt, but it has been lost over the years.
photoKU3532, Prospect Water Tower, Brooklyn NY
Closeup of bolt. The cross, not the hole, is the exact triangulation point.
photoKU3532 Original documentation, Brooklyn NY
Figure from the original report of the triangulation of NYC in 1903 - 1908, showing the layout and bearing lines from the Prospect Water Towrer.

I suggest that this mark, KU3532, is the same mark that is described in KU1297, and that if you've found one you've found them both. The information in the headers for this one says "bench mark disk," but in the detailed description it says it's a bolt in the middle of a large disk, just like KU1297. The large disk (containing the arrow pointing north and an inscription) is missing, and you can see where it used to be and the roots of its 3 anchors still in the stone. Note that KU1297 has been removed and re-installed over the years, like the proverbial knife that's had two blades and three handles but is still "the same" knife. See my entry and the previous finder's entry for KU1297 for more info.

[This entry was edited by LeoGeo on Tuesday, July 12, 2005 at 8:23:36 AM.]

This benchmark is still in its position and in relatively good shape. However, the brass disc detailing the history of the spot has been removed. Could not get an GPS position as the benchmark is under foliage.

Documented History (by the NGS)

01/01/1903 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1903 (ATM) STATION IS A HIGH MASONRY TOWER WITH A CONICAL APEX, AND IS SITUATED AT THE SE CORNER OF FLATBUSH AVENUE AND EASTERN PARKWAY, BOROUGH OF BROOKLYN, KINGS COUNTY, NEW YORK CITY. IT WAS OCCUPIED AT VARIOUS TIMES DURING 1903, 1904, 1905 AND 1907 BY MR. FREDERICK W. KOOP, ASSISTANT ENGINEER, WHO DETERMINED THE STATION BY SUSPENDING A HEAVY PLUMB BOB FROM THE APEX OF THE TOWER. THE STATION WAS ALSO CHECKED BY PLUMBING THE APEX DOWN WITH A TRANSIT. THE STATION WAS MARKED BY A COPPER BOLT 1/2 INCH IN DIAMETER, COUNTERSUNK IN THE CONCRETE FLOOR AND FASTENED WITH SOLDER. STATION IS REACHED BY FLATBUSH AVENUE TROLLEY FROM BROOKLYN BRIDGE, GETTING OFF AT EASTERN PARKWAY.
01/01/1932 by CGS (SEE DESCRIPTION)
RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1932 (FLG) THIS TOWER WAS TORN DOWN IN 1930. A LARGE BRASS DISK, SET IN A GRANITE POST, WHICH IS EMBEDDED IN CEMENT NOW MARKS THE STATION. THIS MARK WAS SET BY THE BOROUGH ENGINEERS. THE FOLLOWING NOTATION WAS MADE ON THE DISK--CENTER OF COORDINATES FOR BROOKLYN. THE TABLET IS 8 INCHES IN DIAMETER. IT IS LOCATED NEAR THE FOOT OF THE SLOPE OF THE RESERVOIR EMBANKMENT, ON THE NW SIDE. THE WATER COMMISSION MAINTAINS AN OFFICE IN THE RED BRICK BUILDING ON THE S SIDE OF THE EMBANKMENT.
01/01/1932 by CGS (GOOD)
RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1932 (RWW) RECOVERED IN EXCELLENT CONDITION, FROM THE ORIGINAL DESCRIPTION. THE STATION HAS BEEN ACCURATELY RE-MARKED BY THE BOROUGH ENGINEER. A COMPLETE DESCRIPTION FOLLOWS--THIS STATION IS LOCATED IN THE PARK SLOPE SECTION OF BROOKLYN, JUST E OF GRAND ARMY PLAZA BETWEEN EASTERN PARKWAY AND FLATBUSH AVENUE. IT IS ON THE THIRD TERRACE OF THE LAWN IN THE NW CORNER OF THE PROSPECT PARK RESERVOIR GROUNDS. THE HIGH MASONRY TOWER, WHICH FORMERLY MARKED THE STATION HAS BEEN RAZED. PRIOR TO THE RAZING OF THIS TOWER THE STATION WAS ADEQUATELY REFERENCED WITH 1ST ORDER ACCURACY TO PERMIT PRECISE REESTABLISHMENT. STATION IS NOW MARKED BY THE CENTER HOLE IN AN 8-INCH ROUND METAL DISK STAMPED BOROUGH BROOKLYN-U.S.C. AND G.S., WITH A DIRECTION ARROW POINTING N, SET IN AN 8-FOOT OCTAGONAL WHITE GRANITE SHAFT SET IN CONCRETE AND PROJECTING 10 INCHES ABOVE GROUND. THIS STATION IS THE POINT OF ORIGIN FOR BOROUGH OF BROOKLYN SURVEYS.
01/01/1954 by CGS (SEE DESCRIPTION)
RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1954 (JB) STATION WAS RECOVERED IN GOOD CONDITION. REVISE THE DESCRIPTION AS FOLLOWS-- STATION IS LOCATED IN THE NW SECTION OF MT. PROSPECT PARK, SE OF THE INTERSECTION OF UNDERHILL AVENUE AND EASTERN PARKWAY. THERE IS A LIMESTONE RETAINING WALL E OF THE BROOKLYN PUBLIC LIBRARY, CENTRAL BRANCH, AND THE MARK IS 38 FT. E OF THIS WALL FROM A POINT 80 FT. S OF THE N END. THE STATION IS MARKED BY A CROSS CUT IN A 1-IN. BRASS PLUG SET IN A 48-IN. GRANITE POST. THE TOP OF THE POST IS HEXAGONAL AND EXTENDS ABOUT 10 IN. ABOVE THE GROUND. THE CROSS CUT IS ABOUT 1/4 IN. NE OF A SMALL DRILL HOLE IN THE CENTER OF THE PLUG. ON TOP OF THE GRANITE POST AND AROUND THE PLUG THERE IS A 9-IN. BRASS PLATE, WITH AN ARROW POINTING N, WITH THE FOLLOWING INSCRIPTION--PROSPECT WATER TOWER ORIGIN OF CO-ORDINATES - BROOKLYN USC AND GS NO 2. THE PLATE WAS CONSTRUCTED WITH A 1-1/2-IN. HOLE IN THE CENTER TO FIT AROUND THE BRASS PLUG. THE ARROW IS AT THE APEX OF A TRIANGLE AROUND THE HOLE. A BRIEF HISTORY OF THE STATION--ORIGINALLY, THE STATION WAS THE CENTER OF THE TOP OF A HIGH WATER TOWER AT A RESERVOIR SITE. IN 1930, THE WATER TOWER WAS RAZED BY MUNICIPAL AUTHORITIES. BEFORE THE TOWER WAS DEMOLISHED, ENGINEERS OF THE BROOKLYN BUREAU OF HIGHWAYS AND SEWERS REFERENCED THE TRIANGULATION STATION BY MARKS IN THE NEARBY RETAINING WALL AND REMARKED THE STATION IN DECEMBER 1931 BY THE PRESENT GRANITE POST WITH A COPPER PLUG AND PLATE. A SMALL HOLE WAS PUNCHED IN THE CENTER OF THE PLUG TO MARK THE TRIANGULATION STATION. SEVERAL YEARS LATER, THE ENTIRE MARK WAS REMOVED BECAUSE OF A LANDSCAPING PROJECT. WHEN TERRACING HAD BEEN COMPLETED, THE GRANITE POST WAS RESET IN 1937 BY THE PARK DEPARTMENT AT AN ELEVATION 8 FT. LOWER THAN THAT OF 1931. IN 1939, THE BROOKLYN BUREAU OF HIGHWAYS AND SEWERS CHECKED THE POSITION AND REMARKED THE CENTER OF THE STATION BY THE CROSS CUT IN THE PLUG JUST NE OF THE CENTER HOLE. PERSONNEL OF THE EASTERN DISTRICT OFFICE RECOVERED THE STATION A YEAR AGO. THE ARROW ON THE 9-IN. PLATE WAS NOTED TO BE POINTING S INSTEAD OF N. THE POST MUST HAVE BEEN TURNED AROUND WHEN RESET IN 1937. THE BROOKLYN BUREAU OF HIGHWAYS AND SEWERS RESET THE PLATE IN DECEMBER 1953 TO HAVE THE ARROW POINT N AS INTENDED. IN MY PRESENCE, MEASUREMENTS WERE MADE TO REFERENCE CUTS IN THE RETAINING WALL BY THE BROOKLYN ENGINEERS WHO CHECKED THE CROSS IN THE PLUG. MR. J. MILTON PETERSON OF THE BROOKLYN BUREAU OF HIGHWAYS AND SEWERS HAS THE RECORDS OF THE TRIANGULATION STATION REMARKING AND CHECKING. HE WENT TO CONSIDERABLE TROUBLE LOOKING UP OLD REPORTS TO GET THE RECORD STRAIGHT.

Control Text

  • The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in January 1999.
  • The orthometric height was scaled from a topographic map.
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The geoid height was determined by GEOID99.

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