(The Berm and Drainage information below give necessary background for understanding this project)
© John D. Olmsted, 2003
The 27 mile Excelsior/South Yuba Mining Canal built for Smartsville hydraulic gold mines, Yuba County, was constructed 1856-59 for $3/4 million. It ran full tilt until the 1884 Sawyer Decision outlawed most hydraulic mining, surviving by irrigating foothill farms. It was purchased by Nevada Irrigation District (NID) in the 1920s and abandoned in the mid-1960s when maintenance costs rose to ten times the irrigation income.
When Excelsior Mining Company, Smartsville, began to develop its hydraulic mines in 1856, Deer and Squirrel Creek waters were already completely claimed by competitors, necessitating a triple-cost connection to the South Yuba. Excelsior's hydraulic mining design required 2000-3000 miner's inches, necessitating a minimum 5' wide canal. Whereas from Deer Creek down to Smartsville would be almost entirely dirt-lined, the stretch down from the South Yuba River would be coming from steeper and steeper slopes, necessitating many wooden flumes.
Heroic workers completed the two interlinked canals in 4 years allowing 600 feet plus of hydraulic head funneling into giant water cannons called monitors. Perched above the mainstem Yuba where it flows into the Sacramento Valley, they would wash away whole hillsides for placer gold from Miocene riverbeds in a Smartsville suburb of Sucker's Flat. The two expensive diversion dams of the Excelsior South Yuba were sited by surveying northeast from the Mooney Flat Saddle above Smartsville to Deer Creek and northeast from Pleasant Valley Saddle to the South Yuba at an exact rise of ten feet per mile. Unlike logging flumes, mining canals were as level as possible.
Both portions of the 27-mile Excelsior South Yuba Canal System defied gravity by transporting water at right angles to the steep canyon slopes, requiring expensive drainage design and extensive maintenance. The combined levee walls and wooden flumeboxes created a man-made mountainside creek channel with one continuous downside/bank to contain it, taking it out of the South Yuba watershed into and across the Deer Creek watershed. Workers from the Italian Alps were involved in the original construction.
Eastern transportation canals like the Potomac River's Chesapeake and Ohio Canal or New York's Erie Canal had wide towpath levees of 15' to 40' width, timber and stone lift locks, and canal volume for an entire river sufficient for narrow but still capacious canal boats. They often perched up to a hundred feet above the parent, free-running river. Never called flumes, the only sections made of wood were viaduct/aqueducts across side creeks /rivers. But, earthen levee/berms similar to transportation canals were used in sierra foothill gold-mining canals. Surveying was accurate enough to allow the wooden segments (flumes) a 1/4" rise in each 16' segment (course).
As in later run-of-river hydropower flumes, gold mining canals were built as level as possible. Mining canals alternated wooden "box flume" sections and dirt "ditch" sections with earthen/rock levee/berms. They traversed areas of greater topographic relief than eastern canals, getting much higher above a parent river. Sometimes wet areas or steep slopes necessitated total stone levees topped by a dirt path as at stone wall East of Highway 49, just before Flume #20. Although the complete gold-mining canal consisted of both "ditch" and "flume" segments, the post Sawyer Decision 1920s NID workers converted original composite 1800's mining canal names to names using only the irrigation term ditch (i.e. as Cascade Ditch, China Ditch, Excelsior South Yuba Ditch, as used for old composite canals today). This fits in with the fact that the Sawyer Decision outlawed hydraulic mining, requiring the Excelsior Co. to convert to irrigating ranches, farms and fruit growers in Nevada and Yuba Counties.
Starting from a primitive-looking ten-feet high rock head-dam at 1500 feet of elevation, (later an afterbay for South Yuba River Rome Powerhouse*) the Excelsior Canal South Yuba Segment snaked around the almost shear granite walls of Devil's Slide to look down on the 1875 Miner's Tunnel at Flume 11 by Hoyt Crossing road/trail. Here the former canal is seen to stay virtually level above the rapidly dropping South Yuba riverbed.
As parts of South Yuba Independence Trail**, used by over 20,000 annually, Flumes 12 to 32 are publicly accessible 2.5 mi. either side of Highway 49 near the historic 1921 South Yuba Bridge***. A living 1500-feet to 1350-feet contour line on the south wall of State Wild and Scenic South Yuba Canyon, the nearly level canal appears to climb higher to westward -- to 800' above the river's boiling spring runoff above Bridgeport Covered Bridge****.
Leaving the South Yuba Canyon after being visible from the Buttermilk Bend Wildflower Trail, Excelsior / South Yuba Canal courses Southwest to Pleasant Valley Saddle crossing Kentucky Ravine Falls seen on Pleasant Valley Road. The South Yuba Watershed portion comprised 11 miles of mud or stone lined levee walls, 6 miles of 64 separate 3'X5' wooden boxflumes, not counting 2/3 mile of man-made cascades to Deer Creek at old Anthony House*****
*Built by the three founders of P G & E in 1896-97 (Eugene DeSabla, John Martin & Romulus Colgate + Cornish miner Tregidgo)
**Started by California Institute of Man in Nature & associate Sequoya Challenge (1969-76) with State Parks co-management since 1988
***Opened in 1921 to replace Jones Bar Road as main connection from Nevada City and Grass Valley to North San Juan
****Built in 1862 as part of toll roads from Virginia City, Nevada to Marysville, California, this is 1 of 2 longest single-span covered bridges
*****Now under Lake Wildwood, was the south end of the 1860s Virginia Turnpike Toll Road that built Bridgeport Covered Bridge
On a 30-degree slope, a canal worker began the base of a 20-feet high, 45-degree slope cut, steepened at bottom for the 5 foot hill wall of the dirt canal cross-section, then 5-feet to 6-feet across its bottom, rising almost vertically 4-feet to an 8-feet wide flat-topped levee/berm, then dropping along 30-feet of fill to the former slope.
From the theoretical 30-degree slope designs, the construction foreman followed the precisely surveyed 10-feet per mile alignment, adjusting the height and angle of the cut slope and the fill slope based on the local hill-slope angle and the amount of rock present and/or needed. Using first workers with shovel, bar, pick and wheelbarrow, later with work horses using the previously created levee for access and materials storage, the relatively complex cut and fill and canal shaping process was achieved. Hundreds and hundreds of workers, horses, mules and half a dozen worker camp sites were involved. In significant multi-mile areas of shallower slopes, no wooden flumes or carpenters were needed with shallow, sand-carrying side creeks allowed to spill into the canal. Sometimes wet areas or very steep slopes necessitated stone wall levee construction. Annual levee maintenance included spotting water or plants on the downslope (indicating leakage), and cutting of young trees and shrubs that, after later growth, might break the levee by root swelling or falling over.
After initial construction in the late 1850s, various flood episodes such as 1861-62, 1884-85, etc. caused temporary closing of the Canal and necessitated immediate levee/berm repair via either conversion from dirt to rock, or to in-ditch flumes with no legs, or if absolutely necessary, to more expensive wooden flumes, increasing their proportion in the overall canal design. Levee repairs after "Excelsior Ditch" initial closure in 1963 are covered on a 3rd page text sections under "Decommissioning" & Recent Maintenance".
Miles of flumes snaked through the steep rock or forest walls of the South Yuba canyon, surrounded by Douglas Fir and Canyon Oak, hiding awkward leg locations from all but repair crews (as at double S-shaped #37). The basic structure was the 3' X 5' wide wooden flume box, which was at lower Sierra locations supported by wooden underpinnings - stringers beneath the boxes on rail-tie like joists, and paired, braced, topped support legs To the Ditchtender atop the 12-inch wide to 18-inch wide walk-plank, the imbricated cross-bar tops looked like a solid bridge in the distance, but one false step in icy winter or one rotten plank anytime could cause a broken leg or worse. Atop a flume 40 feet over a creek or hundreds of feet above the river could be a little dizzying for new recruits. By the 1970s, one's paces had to become exactly 3.2 feet apart, minimizing falling through rapidly aging 25-35 year-old walk planks. And in 1988, all surviving western Flumes were burned up in the 49er Fire (Flumes 30 to 64).
Preferred local* flumebox materials were 16' long sugar pine planks** 1.25" X12" up to 1.25 X18" and 4-feet high cedar uprights 4'X4' with 8-feet notched 4'X4' cedar "box-tops" every 3.2 feet, attached atop 8-feet railroad-tie-like cedar 4"X4" joists, with angled sugar pine 1.25" X 6" side braces every fifth upright. 1/2" X 4" X 16' cedar bats were nailed over plank cracks***.
*1900s NW yellow cedar fiasco lost of hundreds of feet of flume because of cracking
** Whatever size planks were available were nailed one-wide, lengthwise across the box-tops to connect with ditchtender levee-top trails
***Bat nailing costs in the late 1930s increased plank size to two 18" side planks and 3 16" + 1 12" bottom planks, as existed at 1964 shutdown.
Like the Omega off Highway 20, upper Sierra Flumes were often built on railbed-like rock platforms cut in the hill, to avoid the expensive replacement of wooden legs. But the Excelsior only had 2 or 3 such installations. 90% had paired long cedar 6" X 6" stringers holding the flume box joists (above), supported every 8-feet by braced, topped 6" X 6" cedars leg pairs called bents with 8-fee cedar tops and 1.25" X 6" pine 'X' braces.
Many side-canyon flumes had a 4-feet to 5-feet wide spillgate in the middle to allow blockage by inserting cross planks for down-ditch repairs by a single "ditchtender" (as at flumes 13, 21, 23, 25 and 28). Side canyons flumes with spillgates needed to be big enough to absorb 2000"-3000" of water without major damage. New (1921) Highway 49 required giant culverts towed up from old Jones Bar Road, to serve the Flume 21 Spillgate at Orzalli Creek.
Perhaps because floods caused new flumes to be built every decade in the 1859-84 hydraulic era, the Excelsior Company workers only used names for the flumes. A surviving Excelsior Worker from before 1920, Phil Personini, supplied much of the data in the 1970s for Excelsior Canal History. He remembered a majority of the names, and that numbering began when Nevada Irrigation Company took over in the mid 1920s. By 1940, 1/2" X 6"X 8" wooden placards with the number were nailed onto reinforced uprights at the ends of each flume.
In a sense, all 6 miles of flumes in the South Yuba Watershed were "problem areas" for ditch / canal construction, caused by 'un-ditch-able' side canyons and/or rock cliffs. The 64 box flumes varied from about 40' long at Downey and Oak Flumes (#23 and #16) to over 1/2 mile length at Head Flume (#1) and at Long Flume (#45). They sometimes spanned waterfall gorges as at Rush Creek (#28) and Owl Creek (#41) or seemed to hang on the near-shear granite walls at Devil's Slide (#s 1-5). One over 50' high (#18) was only built after a big 1930s wildfire had caused an immense landslide 3/4 mile east of Highway 49.
But the most exciting were the 525-feet long Rush Creek-#28 (with 36-feet long 10' X 12' timbers span and 1859 legs and sway braces until 1996), and an "A Frame" Span at the Murphy Flume (#33). The Jones Bar Landslide Flume (one to the west of the Murphy) was built for over 100 feet, 'legless', across a landslide area, protected from ongoing slides by a half-acre roof of 3" X12" 16-feet mine lagging. Legless flumes were also built inside slide-prone levees (#s 17, 29, 31), or ones built when the berm went into a landslide but the ditch bottom remained (#24, being stabilized in grant). Others were just side-canyon 2' X3' crossover boxes as at #6, #15, #21, #25, #36 and #39.
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