Field guide written by surveyor in 1887 pointed to L.A.’s ‘Mother Ditch’

Los Angeles’ chief surveyor stood above the newly unearthed brick and mortar pipe and carefully opened a 127-year-old leather book.

“Here is the pipe. It’s exactly where they said it was in 1887,” said Tony Pratt, carefully pointing to a hand-drawn map in the ancient field guide.

Freddie Eaton was the chief surveyor back then, the field guide noted. Eaton would eventually go on to become the city’s mayor and a prominent figure in the expansion of L.A.

Pratt pulled the old city surveyor’s field report from city archives this week after reading a news account about the discovery of a remnant of the original Zanja Madre — the town’s original water network —beneath a Chinatown construction site.

He traveled to the development site at Broadway and College Street on Friday to inspect the pipe before its scheduled removal Saturday. A 40-foot section of the pipe will be lifted from the ground and preserved for future display.

“The only building that is left from 1887 is the Capitol Milling Co.,” Pratt said, pointing toward the 1883 structure. “Right over there was the Cape Horn Saloon, just a stone’s throw away.”

Make that a brick’s throw. The four-foot-wide “Mother Ditch” pipe was built of two layers of brick and fed by a large water wheel alongside the Los Angeles River. The water supplied an 88-mile network of pipes and irrigation conduits in the young city.

Pratt said he initially came across the old handwritten field survey book while researching the boundaries of an alley near the former Cathedral of St. Vibiana in downtown Los Angeles.

“We still use the survey monuments established back then,” he said.

As Pratt looked on, a vacuum truck was removing dirt from beneath the pipe to ease its removal by crane.

Fredy Ceja, communications deputy for Chinatown-area City Councilman Gilbert Cedillo, said it’s possible Saturday’s pipe-lifting might be delayed because a state permit is required before the brick conduit can be pulled out.

The Zanja Madre’s preservation is being financed by Metabolic Studios’ Lauren Bon, who intends to display a segment of the brick pipe at a replica of the original water wheel next to the Los Angeles River in the Los Angeles State Historic Park.

The new development, at the former site of Little Joe’s restaurant, is a $100-million project called the Blossom Plaza that will feature a five-story apartment complex anchored by first-floor storefronts.

bob.pool@latimes.com

Twitter: @BobsLAtimes