Moving Manholes

[mpallamary]

This is a question for any surveyors in Los Angeles. How many people have had problems with retracing centerline ties, set on manhole rims, wherein the manholes have been moved around, or rest, with no record of the work having been done? If anyone else has had this problem, would you mind commenting?

Thanks

[Ian Wilson]

Having worked in LA, I'll comment.

I have never relied solely upon manhole rim cuts as a means of establishing centerlines. There is no requirement for anyone working on the manhole to provide notice to surveyors. Even if you know what you're looking for, those cuts and punches are damned difficult to find and be certain of.

Having said that, if two or three line up and give me reasonable distance between the "spots", it makes me feel a lot better. If they don't, I don't necessarily throw them out. I want corroborating hearsay evidence (curbs, houses, things built contemporaneously with survey marks that were still on the ground and can be used as "secondary" evidence).

“…landmarks are frequently formed of perishable materials, which pass away with the generation in which they are made; and are often destroyed, as in the case before the Court, by the improvement of the country and other causes, the boundary and corners may be proved by hearsay, from the necessity of the case." Riley v. Griffin, 16 Ga. 141 (1854)

My 2¢...

[mpallamary]

Yes! I agree 100%. I appreciate the reply! It is helpful.

[Dave Lindell]

If you don't trust the punch marks or chiseled "+" marks on a manhole rim, open the manhole and verify the marks by the "hooks" or leads & tacks inside on the chimney wall about 2.5 feet below the rim.. They were set using a transit and plumbed up/down and are called a Sewer Manhole Monument (SMHM).
(The "hooks" were actual cup hooks screwed into the lead plug and used to stretch rubber bands across whose intersection was the centerline intersection, but many got broken off by the sewer workers who kept catching their clothing on them and so would break them off.)
In may cases the cockroaches will completely cover the inside, so bring lighter fluid to spray them and then light a match to torch them if they haven't all scattered by removing the lid.

[mpallamary]

Yikes! Many thanks for that advice. I appreciate this very much.!

[mpallamary]

I found the attached article/instructions on the Internet. Are these the current and applicable standards in LA?

Thanks

[Ca.PLS8200]

This is a problem in the City of Fresno as well. The City streets generally run on the section lines with the section corners serving as the centerline monuments in most intersections. The City runs its sewers down the centerlines of the streets, replacing the section corners with a 36" sewer manhole. Scribes or punch marks are often placed on the rings, but the rings get rotated with street work, or another ring is added with new lifts of asphalt covering the scribes. I only used the ring marks as possible evidence that the section corner position lies somewhere within the center of the ring.

Best section corner evidence are the swing ties located on the curb returns. All we can do is hope that the City appropriately tied them out before they removed and replaced the returns with the larger, ADA compliant returns.

[mpallamary]

Thanks! This is a problem around the state. To my knowledge, LA is the only city/county that sets the hooks inside the manhole as a double reference. I am trying to learn more about that.

[RAM]

I have a different take. Manholes are not placed for survey control. The only purpose of a manhole is to access utilities. A utility company has no responsibility to maintain a manhole as survey control. For the most part a manhole is a great control point, but as a PLS that uses it as such, you are accepting the consequences of your choice. Do manholes move? Yup for a large variety of reasons, primarly road maintenance. IMHO not a problem, but a consequence of using something it is not intended to be used for.

[mpallamary]

Yes agreed! Are you familiar with the hook system used in LA? It goes back to maybe the 1920's and is considered the most reliable and accurate control in LA.

[mpallamary]

Dave Lindell has been kind enough to share his experiences with me, regarding the use of the manhole hooks. I also located an explanation from the late Paul Plutae. Does anyone else have a story they can share with me, for inclusion in my White Paper. If anyone has any pictures they can share, that would be great. The picture I attached was sent to me by Neil Hansen.

[Peter Ehlert]

hunt down Jack Gechter. He has a wealth of knowledge about Chula Vista that is relevant to those damned manhole monuments, even those darn hooks and how they got moved by sewer crews.

[pls5528]

If you don't trust the punch marks or chiseled "+" marks on a manhole rim, open the manhole and verify the marks by the "hooks" or leads & tacks inside on the chimney wall about 2.5 feet below the rim.. They were set using a transit and plumbed up/down and are called a Sewer Manhole Monument (SMHM).
(The "hooks" were actual cup hooks screwed into the lead plug and used to stretch rubber bands across whose intersection was the centerline intersection, but many got broken off by the sewer workers who kept catching their clothing on them and so would break them off.)
In may cases the cockroaches will completely cover the inside, so bring lighter fluid to spray them and then light a match to torch them if they haven't all scattered by removing the lid.

Having worked in LA for many years in the field, I experienced all of what you say above. I remember the waterbugs and cockroaches 6-8" long! But the good thing was Tommy's was close by for a good chili burger for lunch?

[mpallamary]

I submitted a Public Records Act Request to the city of Los Angeles and was a bit surprised at their response. Does this surprise anyone else?

*******************************************************************************************
CITY OF LOS ANGELES
INTER-DEPARTMENTAL CORRESPONDENCE

DATE: 9/02/21

TO: Gregg Vandergriff, PE
Division Engineer
Project Award and Control Division

FROM: William Knight, Acting Engineer of Surveys
Survey Division

SUBJECT: PUBLIC RECORDS ACT REQUEST – 21-7366
Michael Pallamary – Received August 24, 2021 (via web)

REQUEST: City Monumentation records relating specifically to Sewer Maintenance Hole
Monuments, (SMHM).

RESPONSE: In response to the CPRA NextRequest No. 21-7366, the City of Los
Angeles, Survey Division, has attached the documentation as noted within
the attachment area. There is no documented information as to the
procedural origins regarding Sewer Maintenance Hole Monuments,
(SMHM).

ATTACHMENT:
J-Manual Section J 383 Monuments and Monument Accessories
J-Manual Section J 383 Figures
J-Manual Section J 700A
Standard Plans S-701 through S-703

[subman]

Paul Plutae at on time posted the procedure he used for transferring the cup hooks to the surface if that would be of any benefit. It should still be in the archives of this forum.

[mpallamary]

Thanks!

I found Paul's post.

Happy New Year.