Hell Hole Reservoir

Lower Hell Hole Dam (its official name) is operated by the Placer County Water Agency. The agency controls two dams in the Eldorado National Forest and Tahoe National Forest. The water agency gained its power from financing approved by Placer County voters in 1961.

Proposals for the dam date to 1958.[3] In 1964 the first Hell Hole dam was partially complete.[4] The dam collapsed on December 23, 1964.[5] A new dam was completed in 1966.[6] Placer County sought drinking water supplies to fuel growth of its communities in the Sacramento Valley. The gold-rush-era town of Auburn is in Placer County as is the suburban community of Roseville. The agency also sought to generate hydroelectric power to finance its ability to deliver the water to users.

The construction of the present Hell Hole Dam also changed the course of the Rubicon River.

Lowest cataract on Rubicon River before it enters the reservoir

The pre-dam river channel wended its way several miles to its confluence with the Middle Fork of the American River near Ralston Afterbay. Now, In addition to releases from Hell Hole down the pre-dam path, water is diverted through a pipeline to Middle Fork Powerhouse (AKA Stephenson Powerhouse) where it flows into Interbay Reservoir. From here, in addition to releases down the Middle Fork American River, the water is diverted into a tunnel to Ralston Powerhouse and into Ralston Afterbay, where it joins water from the pre-dam path. Oxbow Powerhouse and Oxbow control dam there releases water into the middle fork of the American River just below the spot of the historical confluence.

Water for hydroelectric generation is also shuttled into Hell Hole from French Meadows Reservoir which impounds the Middle Fork of the American River. The water travels through a tunnel to a powerhouse located on the north side of Hell Hole. French Meadows, at 5,200 elevation, is higher than the 4,700-foot (1,400 m) elevation at Hell Hole. The powerhouse at Hell Hole is actually known by the name, French Meadows powerhouse.[10]

The traditional channel of the Rubicon River still maintains water flow from the spillway at Hell Hole Dam and from tributaries of the Rubicon below the dam, such as Gerle Creek (pronounced girly).

The Placer County Water Agency does not take water directly from Hell Hole or the other dam but instead claims rights to the water as it is shipped through the American River System and ends up at Folsom Lake near Sacramento. Folsom dam was originally constructed for the purposes of flood control. The Placer water agency's dams and Ralston are presently known as the Middle Fork Project.

Hell Hole canyon and nearby vicinities initially escaped man-made exploitation during the latter half of the 19th century, but events that occurred then allowed eventual exploitation of Hell Hole during the 1960s.

Rubicon river and upper cataract

The gold rush of 1849 on the South Fork of the American River resulted in establishment of Sierra foothill towns of Auburn, Placerville, Nevada City and Georgetown. The gold rush did not intrude into the higher elevations of the Sierra Nevada range, but the water and timber needs of these towns did intrude into the upper elevations. In one case in 1873 the privately owned, California Water Company[11] employed a scheme to dam Loon Lake to the south of Hell Hole and then sluice the water closer to Georgetown where it could be used by residents and farmers.[12]

Somewhat later, in 1862, the residents of Placer County (Auburn, Foresthill) came upon a scheme to build a road from the Foresthill divide to Squaw Valley with the intent of luring immigrant trains away from Nevada City and into Placerville and neighboring vicinities. George Wharton James, the author, described the road as an ill-fated enterprise: "The grade is frightful. For an hour or more, we go slowly up it stopping every few yards or so to give our horses breath," James wrote of a ride on the old road a half century after it was built. "It is hard enough for horses to go up this grade but to pull heavily-ladened (sic) wagons - it seems impossible, " he concluded. Later attempts to improve this road or forge other wagon roads were not successful.

The Comstock Lode silver rush in the 1860s in Nevada Territory also encouraged the attempt of the gold-rush foothillers to find pathways over the mountains to the riches of the Comstock and the more local Squaw Valley silver excitement.

The roads then brought timber claimants and homesteaders, called locators, who were able to claim public lands. The old homesteads and timber claims were bought by private water companies or hoteliers who sought visitors to the "healthful" mineral springs after much of the timber was depleted by the mid-1880s.

Railroads brought the tourists. Tourists could reach Truckee, California by rail from either San Francisco or Ogden, Utah by the end of the 19th century. The Lake Tahoe Railway and Transportation Company brought them to the lake. One particular resort established east of Hell Hole has a significant relationship to the canyon. Deer Park, just south of Squaw Valley (now a ski area and home to the 1960 Winter Olympics) was a tourist hotel which had a rustic hideaway camp at Five Lakes now in Granite Chief Wilderness. James described the Five Lakes resort as a 160-acre (0.65 km²) timber claim in which the timber had never been cut but in which cabins had been built and rowboats kept in hand for fishing upon the five small lakes.

The Five Lakes are the headwaters of Five Lakes Creek which led James on his 1913 horseback descent into Hell Hole in the company of Bob Watson, the guide. The pair camped at Hell Hole, then ascended the Rubicon River to Rockbound Lake, where they camped again. Rockbound Lake is now in the Desolation Wilderness and is near the headwaters of the Rubicon River. The Sacramento Municipal Utility District controls a dam within the Desolation Wilderness: Rubicon Reservoir. Desolation Wilderness was created in 1969.

Upper Hell Hole looking northwest to Granite Chief Wilderness, May 2005

Placer County's 1961 bond approval allowed its water agency to seek out water supplies that were not already claimed by others. Loon Lake, south of Hell Hole, was already prescripted, but the rugged, untouched Hell Hole was not. In 1934, the State of California took steps to claim any unclaimed water rights along the American River's three forks. In 1962 the rights to the Rubicon River water were conveyed to Placer County.[13]

The Hell Hole dam, a rock-fill-type dam, was completed across the Rubicon River in December 1964. As the reservoir began filling the dam sprung a leak during a flood event and failed completely the next day. The resulting flood washed down the Middle Fork of the American River and washed away the Greenwood Bridge near Auburn.[14]

The Placer County Water Agency began a new dam which was completed two years later and has now stood for 42 years.[15]

Hell Hole Dam was partially completed at the time of extremely heavy storms in December 1964. The downstream rockfill portion was up ~220' above the river bottom, but the impervious core and adjacent zones were only up ~35'. Debris from extreme storm runoff upstream of the dam blocked the diversion outlet, and water rapidly accumulated behind the partially constructed dam. As the water came up it was seeping through the rockfill, and when it crested, the entire mass collapsed in a matter of minutes. A surge went down the canyon, washing out two older suspension bridges below the Long Canyon influx and at the Spanish Dry Diggings crossing near Greenwood. It then washed out the State Highway 49 bridge over the American River just below Auburn.[16] Folsom Dam reservoir absorbed the surge below that point.

• List of dams and reservoirs in California
• List of largest reservoirs of California
• American River (California) topics