In 1859, G.W. Holt and August Conrad constructed a wooden suspension flume 2200 feet long across this valley as a link in the Golden Rock Ditch system, which conveyed water from the South Fork of the Tuolumne River to the mining areas of Groveland (Garrote) and Big Oak Flat. It was considered one of California’s early engineering marvels and is said to have been the highest major flume built during the Gold Rush period. The flume decayed and collapsed with a spectacular crash in 1868. In 1869, Andrew Rocca replaced it with an inverted syphon, the large iron pipe that still remains in place as a monument to pioneer enterprise.