Bureau of Water Works and Supply

I asked an LA Aqueduct Historian about this benchmark, who in turn asked the DWP.  Today I got the answer:

Karl-

Here is what I have found out about the benchmarks you came across.

·         They are on a concrete conduit that carried water by gravity from the LA Aqueduct to Maclay Reservoir. The conduit is called the Maclay High Line. This conduit has been out of service for many decades.

·         The reservoir and high line went into service in 1917 and served parts of the northeast valley. It was located at the corner of Eldridge and Astoria. It was originally called Pacoima Reservoir and later Maclay Reservoir. It was a square reservoir, 280’ on a side, with a depth of about 15 feet and a capacity of 19 acre-feet. It had a timber roof. It was an earth-fill dam with a maximum height of 22 feet and a high water of 1449 feet.

·         The benchmarks were set between 1925 and 1943. They are referenced to the Los Angeles Aqueduct datum. A re-survey of the high line was probably conducted in this period to verify its grade and location within a 25-ft wide right of way or easement.

·         The benchmarks are unrelated to the construction of the LA Aqueduct.

I hope this information helps.

Let me know if you have any other questions.

Fred Barker

This is so cool!