By Scott Belser, Groveland Yosemite Gateway Museum/Southern Tuolumne County Historical Society
The story of Southern Tuolumne County has always been the story of its water: the challenge of water scarcity and how to overcome it. While annual precipitation in Groveland is 39 inches, it is starkly seasonal with only 10% of annual rain falling from May to October. Water shortages are a way of life.
The indigenous Me-Wuk people lived in harmony with these weather patterns. Their use of water for fishing and crop cultivation was in keeping with sustainable natural resources.
However, when European gold-seekers flocked to Big Oak Flat in 1849, the demand for water skyrocketed. Water was crucial in every phase of early gold mining. The stereotypical gold miner panning for gold alongside the stream relied on water to separate the gold from the dirt. However, by the early 1850s, the easy gold deposits were exhausted. More water - all year long – was vital. New mining methods included forcing water-infused slurry down “rockers” and sluice boxes (often called “long Toms”). Ultimately, miners used destructive “hydraulic” mining, spraying enormous quantities of water against hillsides to wash away the earth to access gold-bearing veins underneath. The practice was so harmful to the environment and downstream businesses that it was prohibited by law in 1884. Visitors can still see this devastation in the red “cliffs” off Highway 120 in Big Oak Flat.
Miners recognized the need for water soon after mining started. By 1855 local mining interests started a company – Golden Rock Water - to bring water from the South Fork of the Tuolumne to the gold camps. After some early setbacks the ditch network was completed, and water deliveries began on March 29, 1860, all the way to Big Oak Flat – 25 miles away.
The centerpiece of the water system was the “Big Flume” that crossed a wide gap near present-day Buck Meadows. An engineering marvel of its day, the flume stood 265 feet high with a total span of 2,200 feet. Unfortunately, lack of maintenance on the 11 towers of sugar pine weakened the structure, and it fell spectacularly on July 9. 1868.
Enter a local entrepreneur hero to save the day. Andrew Rocca, born in Genoa, Italy and arrived in California at age 15, had been a successful miner in the area. In March 1869 he purchased an interest in the Golden Rock and began a rapid replacement of the wooden flume with an iron pipe “inverted siphon” that exploited gravity to pass the water across the gap. Thanks in part to volunteer labor by water-deprived miners, the siphon was completed in two months, reopening in July 1869.The repaired ditch system was successful for the next 15 years, making Andrew Rocca a wealthy man. The ditch began a long decline in the 1880s when water-based mining substantially decreased, and Rocca himself moved to Lake County where he died in 1923. Parts of his pipe are still visible near Buck Meadows.
The emergence of hard rock mining (where gold was mined in deep shafts) in the 1880s and ’90s did not require as much water as before. Water resources primarily served residential and ranching needs. Ownership of the Golden Rock passed to a series of smaller mining and power companies who promoted over-ambitious schemes for water supply and power generation for the few remaining mines and short-lived lumber mills. Lack of demand forced the dissolution of the last of these enterprises (Tuolumne Electric) in 1917.
Watch for Part 2, which tells the rest of the story how Groveland overcame its water challenge in the long term.
Scott Belser is Vice President of Southern Tuolumne County Historical Society board of directors, and is considered an expert on our local water history.
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