From an interview with Mr. Frank Shearer, conducted June 10,1940 for a history of Griffith Park. Record held by the Los Angeles City Archive (the original transcrpt is filled with typos).

Fern Dell started in 1912. A bunch of Chinese farmed the land around the Western Avenue entrance nos in is. They drove a tunnel several hundred feet up to the junction of what is now Black o Red oak (at wall ?) tapping the underground water of two canyons. The tunnel was unlined except at the portal, which was composed of wood. During a heavy rainstorm the surface water carred out the wooden portal and then cut the tunnel out clear back to where it terminated, Leaving a sort of gorge or canyon. When the city took over the property it was a jungle of willows with a stream of water which had developed between the tunnel running along the bottom of the canyon. In order to take care of the storm water and to avoid expensive storm drains, we developed a channel with a path along the side of it and cribbed up the sides of what was formerly the tunnel. We had discovered a lot of Woodwardia ferns growing in a canyon above the present Zoo where no one ever awa them and we transplanted them over to the Fern Dell.

Another idea was to show them out to treat the River Bed — that is the way Fern Dell was developed, as a model of what they should do with the river channel. We made a channel that was big enough to take the stream flow from the canyon and made a path on the side. sufficient to carry maximum storm flow from Western Avenue channel and made a path about 8—10 ft. wide to permit public to walk up and down there, rip rapped the banks and planted them full of ferns. We also considered this a model for the beautification of the river channels for the L. A. and arroyo, Pacoima, Big Tujunga and others, with trees and palms in instead of ferns for the embankment.