City of Oakland Benchmarks

wingding · Post by **wingding** » Thu Apr 13, 2017 4:07 am

Does anyone know if the city of oakland is on 88 datum yet ?
Their GIS map has 88 datum contour elevations (based on comparison w/ google earth)
also is there an online method for the benchmarks yet ?

Steve Martin · Post by **Steve Martin** » Thu Apr 13, 2017 6:42 am

The City of Oakland is on the City of Oakland Datum, which is 3' different from NGVD29

Jim Frame · Post by **Jim Frame** » Thu Apr 13, 2017 6:58 am

The City of Oakland is on the City of Oakland Datum, which is 3' different from NGVD29

3.133 below NGVD29, according to https://bsm.sfdpw.org/subdivision/bench ... planes.htm.

Steve Martin · Post by **Steve Martin** » Thu Apr 13, 2017 7:11 am

We use 3.00' base upon information provided by the City Engineer in 1964.

The EBMUD table dates back to 1976 at least and that is what we have used in Oakland ever since.

Jim Frame · Post by **Jim Frame** » Thu Apr 13, 2017 7:42 am

I'm not arguing -- I rarely work in the area anyway -- but I'll add the attached document dated 1941 (I think) to the mix just for fun. It's a little hard to read, being a scan of a so-so copy I was given decades ago (and annotated by the surveyor I got it from) . The salient part is this: "Oakland city datum was determined as 3.068 feet above mean sea level by C.E. Grunsky, 1911."

wingding · Post by **wingding** » Thu Apr 13, 2017 9:00 am

Thank you everyone
So The city Datum is within a few inches of 88 datum...I'll have to be carefull with that

PLS7393 · Post by **PLS7393** » Thu Apr 20, 2017 7:09 am

So The city Datum is within a few inches of 88 datum...I'll have to be carefull with that

Please don't say your still surveying in inches? Lol.

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City of Oakland Benchmarks

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