NYSureshot Posted April 22, 2003 Share Posted April 22, 2003 I started benchmark hunting the other day and the first two findes were under a manhole cover with U.S.C.& G.S. on it. Is it proper/legal to lift the cover to see the actual benchmark??? The two I found were in an urban setting and didn't think it right to lift the cover. What do you all think??? NYSureshot nysureshot1954@yahoo.com Quote Link to comment
rusty0101 Posted April 22, 2003 Share Posted April 22, 2003 First check would be to see if US Power Squadron has recoverd either mark in the past. If they have then I doubt that anyone would have a problem with you checking them as well. Other considerations, where are they located that they require a manhole cover. If they are in the middle of the street, leave them alone. If they are in a sidewalk, or a median, you may be ok. Keep safety in mind. If there is a significant potential for injury, it probably is not worth it. Also take into consideration the weight of a manhole cover. A standard 3 foot disk weighs in the neighborhood of 150 to 200 lb. If this is a 1 foot disk in a sidewalk, you may not need any extra tools. It is possible that you can lift it out with your fingers, but don't bet on it. It likely has sand or other grime helping to hold it in place. -Rusty Quote Link to comment
+Kewaneh & Shark Posted April 23, 2003 Share Posted April 23, 2003 I'm assuming that what you're calling a manhole is a small 6"-12" protective cover called a handhole and not a true 30"-36" manhole. Generally, it's ok for you to lift a cover to check out a benchmark. You may get a few people wondering what you are doing, but it's not illegal. Chances are that the logo cap is a hinged lid, or just a drop-in cover, and the benchmark is just a few inches below it. It's common to find newer benchmarks in protective casings recessed in the ground, especially in busy urban areas, but I've seen older ones from the 40's & 50's like that too. This one, GU1074, is like that. Just be careful when you remove the cover. If it's been a while since it's been removed, the metal could be rusted and it could take some work to get it off, and the last thing you want is to damage it. Which benchmark are you looking for? A link would be helpful. Let us know what you find. Keep on Caching! - Kewaneh Quote Link to comment
survey tech Posted April 23, 2003 Share Posted April 23, 2003 There are not too many markers under covers in sidewalks or other foot traffic areas, but its especially important to be careful with them. If the cover is damaged or not put back properly, a person stepping on it can easily break an ankle or a leg when it gives way. Quote Link to comment
Z15 Posted April 23, 2003 Share Posted April 23, 2003 Here is one in a manhole. Although the recovery does not note it, I am aware this was recovered by MDOT within last 5 yrs. DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 6.75 1 National Geodetic Survey, Retrieval Date = APRIL 23, 2003 QK0249 *********************************************************************** QK0249 DESIGNATION - A 2 QK0249 PID - QK0249 QK0249 STATE/COUNTY- MI/MACKINAC QK0249 USGS QUAD - ST IGNACE (1976) QK0249 QK0249 *CURRENT SURVEY CONTROL QK0249 ___________________________________________________________________ QK0249* NAD 83(1994)- 45 50 50.27400(N) 084 43 23.98667(W) ADJUSTED QK0249* NAVD 88 - 177.331 (meters) 581.79 (feet) ADJUSTED QK0249 ___________________________________________________________________ QK0249 LAPLACE CORR- -3.94 (seconds) DEFLEC99 QK0249 GEOID HEIGHT- -35.39 (meters) GEOID99 QK0249 DYNAMIC HT - 177.337 (meters) 581.81 (feet) COMP QK0249 MODELED GRAV- 980,647.2 (mgal) NAVD 88 QK0249 QK0249 HORZ ORDER - FIRST QK0249 VERT ORDER - FIRST CLASS II QK0249 QK0249.The horizontal coordinates were established by classical geodetic methods QK0249.and adjusted by the National Geodetic Survey in February 1997. QK0249 QK0249.The orthometric height was determined by differential leveling QK0249.and adjusted by the National Geodetic Survey in June 1991. QK0249 QK0249.The Laplace correction was computed from DEFLEC99 derived deflections. QK0249 QK0249.The geoid height was determined by GEOID99. QK0249 QK0249.The dynamic height is computed by dividing the NAVD 88 QK0249.geopotential number by the normal gravity value computed on the QK0249.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 QK0249.degrees latitude (g = 980.6199 gals.). QK0249 QK0249.The modeled gravity was interpolated from observed gravity values. QK0249 QK0249; North East Units Scale Converg. QK0249;SPC MI N - 120,792.991 8,176,806.554 MT 0.99993188 +1 38 44.0 QK0249;UTM 16 - 5,079,602.006 676,770.859 MT 0.99998417 +1 38 02.0 QK0249 QK0249: Primary Azimuth Mark Grid Az QK0249:SPC MI N - MACKINAW CITY MUNICIPAL TANK 178 31 46.6 QK0249:UTM 16 - MACKINAW CITY MUNICIPAL TANK 178 32 28.6 QK0249 QK0249|---------------------------------------------------------------------| QK0249| PID Reference Object Distance Geod. Az | QK0249| dddmmss.s | QK0249| QK0736 MACKINAC IS GRAND HOTEL TANK APPROX. 7.5 KM 0862642.3 | QK0249| QK0726 ROUND ISLAND LIGHT APPROX. 8.4 KM 0931116.9 | QK0249| QK0734 MACKINAW CITY MUNICIPAL TANK APPROX. 7.1 KM 1801030.6 | QK0249|---------------------------------------------------------------------| QK0249 QK0249 SUPERSEDED SURVEY CONTROL QK0249 QK0249 NAD 83(1986)- 45 50 50.26683(N) 084 43 23.98582(W) AD( ) 1 QK0249 NAD 27 - 45 50 50.22400(N) 084 43 23.80900(W) AD( ) 1 QK0249 NGVD 29 - 177.373 (m) 581.93 (f) ADJ UNCH 1 2 QK0249 QK0249.Superseded values are not recommended for survey control. QK0249.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. QK0249.See file dsdata.txt to determine how the superseded data were derived. QK0249 QK0249_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TFR7677179602(NAD 83) QK0249_MARKER: P = PIPE CAP QK0249_SETTING: 17 = SET INTO TOP OF METAL PIPE DRIVEN INTO GROUND QK0249_STABILITY: D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY QK0249 QK0249 HISTORY - Date Condition Report By QK0249 HISTORY - 1954 MONUMENTED MIDH QK0249 HISTORY - 1934 GOOD NGS QK0249 HISTORY - 1956 SEE DESCRIPTION CGS QK0249 QK0249 STATION DESCRIPTION QK0249 QK0249'DESCRIBED BY MI DEPT OF HIGHWAYS 1954 (CTH) QK0249'STATION IS SITUATED 1.5 MILES WEST OF ST. IGNACE AT THE NORTHERN END QK0249'OF THE MOLE QK0249'SECTION COMPRISING THE NORTHERN APPROACH TO THE PROPOSED QK0249'STRAITS OF MACKINAC BRIDGE. QK0249'THIS POINT IS THE ORIGINAL NORTHERN POINT QK0249'DESIGNATING THE CENTERLINE OF THE BRIDGE AND QK0249'WAS ESTABLISHED BY THE MICHIGAN QK0249'STATE HIGHWAY DEPARTMENT. THE MARK IS A 2-BY 48-INCH IRON PIPE QK0249'WITH CAP, QK0249'WITH TRIANGLE AND PUNCHMARK INSCRIBED ON TOP. THIS MARK IS 8 QK0249'FEET BELOW THE PRESENT QK0249'GROUND LEVEL, ACCESS TO SAME BY BRICK-SIDED CIRCULAR QK0249'MANHOLE WITH STANDARD SEWER MANHOLE QK0249'COLLAR AND LID. THE PIPE QK0249'MARKER IS SET IN CONCRETE, WITH JUST THE CAP QK0249'PROTRUDING FROM THE CONCRETE. QK0249'UNLESS TRANSFERRED TO THE BRIDGE LEVEL LATER THIS MARKER WILL QK0249'BE QK0249'INACCESSIBLE AFTER THE BRIDGE IS COMPLETED. QK0249 QK0249 STATION RECOVERY (1934) QK0249 QK0249'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1934 QK0249'1.5 MI W FROM ST IGNACE. QK0249'1.5 MILES WEST OF ST. IGNACE, MACKINAC COUNTY, AT THE NORTHERN QK0249'END OF THE MOLE SECTION COMPRISING THE NORTHERN APPROACH TO THE QK0249'PROPOSED STRAITS OF MACKINAC BRIDGE, THE NORTHERN POINT QK0249'DESIGNATING THE CENTERLINE OF THE BRIDGE, 8 FEET BELOW THE QK0249'PRESENT GROUND LEVEL, ACCESS TO SAME BY BRICK-SIDED CIRCULAR QK0249'MANHOLE WITH STANDARD SEWER MANHOLE COLLAR AND LID. A 2- BY QK0249'48-INCH IRON PIPE WITH CAP, WITH TRIANGLE AND PUNCHMARK INSCRIBED QK0249'ON TOP, SET IN CONCRETE WITH JUST THE CAP PROTRUDING. QK0249'NOTE-- UNLESS THIS MARK IS TRANSFERRED TO THE BRIDGE LEVEL QK0249'LATER, THIS MARKER WILL BE INACCESSABLE AFTER THE BRIDGE IS QK0249'COMPLETED. QK0249 QK0249 STATION RECOVERY (1956) QK0249 QK0249'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1956 (WNM) QK0249'THE STATION MARK WAS RECOVERED AS DESCRIBED AND FOUND IN GOOD QK0249'CONDITION. THE AREA IS QK0249'STILL UNDER CONSTRUCTION AND THE DESCRIPTION IS ADEQUATE AT THE QK0249'PRESENT TIME. QK0249' QK0249'MR. JACK KENNY, BRIDGE ENGINEER, STATES THAT THE CIRCULAR MANHOLE QK0249'THAT IS BUILT AROUND THE QK0249'STATION MARK WILL BE EXTENDED UP TO THE BRIDGE APPROACH AND THE QK0249'STATION MARK WILL BE PRESERVED. *** retrieval complete. Elapsed Time = 00:00:03 Quote Link to comment
NYSureshot Posted April 24, 2003 Author Share Posted April 24, 2003 On the subjest of the "Man Hole Cover" the disk is about 18 inhes and is of cast iron with U.S.C.&G.S. cast on it. The location is right on with the cords. I'm going out soon to "uncover" the one with the least traffic around it. They are both off the street in an urban setting, but in areas of new road/sidewalk condstruction. I think they are covered in this way so as not to cover them up with layers of dirt and concrete. The benchmarks are designated OF1781 and OF1761. I'm also going to go out and look for a cheep dig. camera. I don't want to put too much mony into one now seing I have a good film rig. NYSureshot Quote Link to comment
NYSureshot Posted April 24, 2003 Author Share Posted April 24, 2003 Ok all, Went to OF1781 this morning with a crow bar to lift the cover. I took a too large a bar and found out that my good old Gerber multi-tool did the job. The medalion was in place about 10 to 12 inches down below grade. There was alot of dirt but you could make out the inscription. Thanks NYSureshot Quote Link to comment
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