casamig Posted May 8, 2015 Share Posted May 8, 2015 hello, i am new to geo and new to this forum. here's the story: over the last couple of years, someone has been digging up my front lawn. I re-plant grass only to have it dug up again some time after. recently, i happen to catch of couple of official looking gents doing just this. i approached them and asked "what gives?" they told me that on my property was "city marker 218" (i live in chicago) and that they were doing utility work in the area and were using surveying tools and this marker as a reference. they suggested i call the city and have them install a new more accessible box. i called the city and NO ONE knew what the heck i was talking about. i caught the bug and continued to call, getting transferred to and from various departments. finally, i got a hold of a gent who asked me to email him pictures. i dug up the marker (which i think is referred to as a "bolt" or "disk") I did. within hours (yes, VERY surprising), a survey gent was at my house. after looking at the thing, he concluded that it was an ancient lamp post base. i was polite but refuted his conclusion asking why various construction/survey crews would seek out a lamp post base. furthermore, there was only the one pin at the center of the circular concrete base with 2 raised channels pointing due north and due south. furthermore, there was no means by which to mount a post such as threaded rods. AND why would the survey gents refer to it as a marker. i'm not sure i convinced him but he said he'd run it up the chain of command. i no longer care about the future of my lawn but MUST learn the nature and history and truth of this so called marker. i have tried to attach pictures I've taken of it but can't seem to figure that out (it asks for a url. i took pictures on my point and shoot and i'm quite terrible with technology) it's approximately 2 feet in diameter. the outer rim is clay tile with the center being poured concrete. at the center is a metal "pin" resembling re-bar rising approximately one inch above the concrete base. there are two raised poured concrete channels pointing due north and south. there is NO text anywhere. it is buried approximately one foot under ground. the marker is found in Chicago Illinois at the south west corner of West Patterson ave and North Leclaire Ave (zip code: 60641) i suspect i have come to the correct place and EAGERLY await any help.... Thank you!!! I'll happily post pictures if you tell me how. -casamig Quote Link to comment
ArtMan Posted May 8, 2015 Share Posted May 8, 2015 First, welcome to the forum. Glad you caught the bug! Few of us can claim to have a benchmark on our property, so you are in a small, elite club! Most readily-identified benchmarks are survey disks, typically circular, a few inches across, and stamped with identifying information. But a benchmark can also be a chiseled mark in stone or concrete, the top of a tall structure (church spire, factory chimney, etc), a nail, or really anything that can be described and identifed by surveyors in the future. So your mark may indeed be the remnant of a former lamp post which, at the same time, serves as a marker of known elevation. It appears that the benchmarks are maintained by the water department, which makes some sense since they would need elevation information to make sure water flows downhill as intended. They are listed, hundreds of them, in a spreadsheet on the Chicago city website. Incidentally, I got to the website http://www.cityofchi...benchmarks.html by Googling chicago illinois survey monuments. Here's what I found there: BENCHMARK NUMBER: 218 NORTHING: 1923767.11 EASTING: 1141689.489 ELEVATION: 33.932 LOCATION DESCRIPTION: 9.7' E. OF W. LINE OF LECLAIRE AVE. LOCATION DESCRIPTION: 210.4' N. OF S. LINE OF PATTERSON AVE. MARK DESCRIPTION: IN BOOKS 425 AND 426 YEAR BENCHMARK ELEVATION FIXED: 1978 BOOK NUMBER: 425 LATITUDE: 41.9468873007 LONGITUDE: -87.7545950055 ESTIMATED LOCATION: 41.94688730070, -87.75459500550 If you take that last line, and put it in a Google Maps search box, it should show you the location to a pretty good degree of accuracy. Note: I don't know what books 425 and 426 refer to; maybe someone else here will, but I assume it's a city record of some sort. Also, the 1978 date that elevation was fixed is not necessarily how old the object is, just when its elevation was determined Hope this is of some help. Maybe someone else can help you with posting a photo, which we would like to see. If you can put the photo online somewhere where it has a URL, you can add a photo. You can't upload a picture directly to the forum; it has to be hosted elsewhere. Google Docs and Dropbox would work, but there may be other free and easier solutions. Anyone? ArtMan Quote Link to comment
casamig Posted May 10, 2015 Author Share Posted May 10, 2015 Dear ArtMan, Thank you so very much for your reply, your welcoming, and your research. I'm left very impressed and very interested what what you guys do here. It seems very fun and right up my alley. My wife is encouraging me (we agree I need a hobby) to pursue this. I suspect you'll be hearing more from me. I think I was able to successfully upload the pictures. Please tell me if it works. http://postimg.org/gallery/15st3s9ke/ -casamig Quote Link to comment
+Gungadoy Posted May 10, 2015 Share Posted May 10, 2015 Welcome....Wow, you weren't kidding; that's one big benchmark and a very interesting one at that. I can see why you've decided to cave-in with the lawn problem and see what it's about. This website has some great reading material about the origins of benchmarks: http://www.ngs.noaa.gov/web/about_ngs/history/Survey_Mark_Art.pdf Quote Link to comment
Bill93 Posted May 10, 2015 Share Posted May 10, 2015 (edited) The pictures work. It looks to me like they constructed it just to be a bench mark, using a clay tile that they filled with concrete and put the rod in. Edited May 10, 2015 by Bill93 Quote Link to comment
ArtMan Posted May 10, 2015 Share Posted May 10, 2015 You're welcome, and thanks for the pix. I can't tell from the photos, but I wonder if there is a small (about 1-2 mm) dimple in the top of the protruding metal piece. Often, there is such a "datum point" to help surveyors using the mark know where to rest their plumb bob. Quote Link to comment
+Holtie22 Posted May 11, 2015 Share Posted May 11, 2015 I would check with the local surveyors who were using the mark. I have seen a concrete-filled clay tile with an iron rod in the center used as a boundary marker in my town, although it dated to the 1930's. Given the location at what appears to be the intersection of the right-of-way lines of the two streets, an original purpose as a cadastral marker seems more likely than a benchmark, even if was used as such at a later date. Quote Link to comment
+Holtie22 Posted May 11, 2015 Share Posted May 11, 2015 After looking at the database link provided by ArtMan, I think the gent from the city may have been right - it could have been an old lamp post base re-purposed as a benchmark in 1978. The description says it is 9.7 feet East of the West line of Leclaire, and 10.4' (not 210.4') North of the South line of Patterson, which is exactly where the coordinates place it in Google Earth. This means that the sidewalks are within the right-of-way limits of the streets, and that rather than being at the intersection of the street lines, it is symmetrically placed inside those lines - right where you might expect to find a street lamp. Is that a conduit (gas or electric) leading into the squared off portion of the concrete? Of course, this interpretation would also mean that the lawn is within the highway right-of-way and not necessarily yours at all! Quote Link to comment
ArtMan Posted May 11, 2015 Share Posted May 11, 2015 Of course, this interpretation would also mean that the lawn is within the highway right-of-way and not necessarily yours at all! Maybe, but might it also be possible that the city has a utility easement and that the property is casamig's? Quote Link to comment
+Holtie22 Posted May 11, 2015 Share Posted May 11, 2015 Of course, this interpretation would also mean that the lawn is within the highway right-of-way and not necessarily yours at all! Maybe, but might it also be possible that the city has a utility easement and that the property is casamig's? Many scenarios are possible. A Bundle of Rights Quote Link to comment
casamig Posted June 16, 2015 Author Share Posted June 16, 2015 Of course, this interpretation would also mean that the lawn is within the highway right-of-way and not necessarily yours at all! Maybe, but might it also be possible that the city has a utility easement and that the property is casamig's? Many scenarios are possible. A Bundle of Rights That would make sense. The city of chicago owns the front most lawn (on which this marker is located) and the side walk. chicago property owner's property does not start until "our side" of the side walk. I'm not sure what the official name for the cities property there is but chicagoans have always called it the "parkway". we are responsible for its maintenance but it is in fact owned by the city..... so..... probably a lamp post then right? Quote Link to comment
Wintertime Posted June 19, 2015 Share Posted June 19, 2015 Casamig, I was about to say what Holtie did: next time you see people surveying in your area, grab one of them and ask where they read about the mark in your front yard. Obviously they found it in some database or other, else they wouldn't know to look for it under your lawn. Quote Link to comment
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