The Flume Trail is pretty much the ride people mean when they talk about mountain biking at Lake Tahoe. You climb out of Spooner Lake, roll past a smaller lake called Marlette, and then ride a skinny trail with Tahoe spread out below you.<\/p>\n
For two summers, you couldn’t ride the whole thing. Nevada closed the west side of the Spooner Lake backcountry while it rebuilt the dam that holds Marlette Lake in place, and State Parks didn’t reopen it until early October.<\/p>\n
So why tear out a dam that’s been holding water since 1873?<\/p>\n
Marlette Lake didn’t start out as a place to fish or ride bikes. It was a water tank for Virginia City, the Comstock Lode mining town, and the dam went in so the town and its mines wouldn’t go thirsty.<\/p>\n
Granite Construction, the contractor on the rebuild, says the old system included what was once the world’s largest inverted siphon, plus more than 45 miles of wooden flume that floated logs from the Tahoe Basin over to Virginia City. An inverted siphon is basically a sealed pipe that drops down one side of a valley and climbs back up the other. Water pressure from the high end does all the lifting.<\/p>\n
The lake still does a version of that job today. The state says the Marlette Lake Water System<\/a> supplies Storey County and Carson City, and Carson City buys a share of what it delivers.<\/p>\n As for the dam itself, Storey County’s project slides say it stood 26 feet tall when it went in and was raised to 37 feet in 1876. The state says it was raised again in 1959. I couldn’t find a clean height for the rebuilt dam in anything the state or the contractor has put out, so I’m not going to guess at one.<\/p>\n Water was getting through it. A 2017 inspection by the Nevada Division of Water Resources found seepage, and the state’s own completion notice says that could’ve eventually led to a catastrophic failure.<\/p>\n Seepage doesn’t sound like much. In an earthen dam, it’s a big deal. A dam like this is basically a giant, tightly packed pile of soil and rock, and when water keeps working its way through the body of it, that soil gets soaked. Shake soaked soil hard enough, say in an earthquake, and it can start acting more like a thick liquid than a wall. Engineers call that liquefaction. And that’s exactly the risk the contractor says the seepage pointed to.<\/p>\n Then there’s what sits below it. According to Granite, Lake Tahoe and State Route 28, the highway along Tahoe’s east shore, are both downstream of Marlette, and a failure would also disrupt water deliveries to Carson City and Storey County. Frankly, that’s about as clear a case for disaster-prevention money as you’re going to find, and that’s where the money came from: FEMA’s Pre-Disaster Mitigation Fund, alongside the State of Nevada.<\/p>\n We’ve had a bit of a run on old dams around here lately, from the century-old arch dam near Prescott that overtopped<\/a> earlier this month to the Columbia River dam getting anchors drilled into bedrock<\/a>. Marlette’s fix was arguably the most drastic of the bunch.<\/p>\n You don’t drain it, for starters. The state lowered Marlette by about 20 feet and left roughly 20 feet of water in it while the work went on. It also phased the job so Hobart Reservoir and the rest of the system could keep Virginia City supplied.<\/p>\n But that’s still 20 feet of water leaning on the thing you want to rip out. That’s what a cofferdam is for. It’s a temporary wall that holds the water back so crews can work on dry ground behind it, and once the real dam is finished, the temporary one comes out.<\/p>\n This one was made of water. Storey County’s slides<\/a> say Aqua Dam Company of Scotia, California, made three polyethylene tubes with woven outer sleeves for a cofferdam 25 feet high. They were filled with water from the lake, and Granite’s project page<\/a> calls it “the largest AquaDam ever installed by Granite.” There’s something pretty elegant about using the lake to hold back the lake, if you ask me.<\/p>\n With the tubes in place, crews pumped out the water trapped between the two dams. Then they took out the old embankment and the underground spillway pipes, and dug down to bedrock, according to the county.<\/p>\n The new dam was built back up from there as a fresh earthen embankment. The contractor planned to reuse about 16,000 yards of material from the site, and to beef up the back of the dam to keep it from sliding. The main outlet pipe is now a 24-inch steel pipe encased in concrete. The state’s list adds seismic upgrades, spillway improvements, and new discharge piping and outlet valves.<\/p>\n The calendar was the other headache. Environmental rules only allowed work from May through October, so the job got split across 2025 and 2026, with a winter shutdown in between.<\/p>\n Getting there wasn’t easy either. The only way in is a six-mile dirt road, an old Forest Service route Granite widened for its heavy equipment. The contractor even mapped out landing spots for medical helicopters, which tells you how remote this place is.<\/p>\n It’s busy up there in other ways, too. Bald eagles nest along the haul road. And as the lake dropped, state cultural monitors started turning up possible Native American sites and mining artifacts from the late 1800s along the newly exposed shore.<\/p>\n Granite puts the bill at $23.5 million. Storey County’s slides list a $10 million FEMA grant and call it roughly a $21 million project, so I’d treat the exact total as a bit of a moving target, depending on who’s counting what.<\/p>\n Nevada State Public Works hired Lumos & Associates to engineer the new dam and Granite to build it. The state says the work started in June 2025 and wrapped up on schedule this October.<\/p>\n That’s up to the snow. The state says natural recharge depends mostly on winter snowpack, and its models give the lake four to six seasons to get back to normal.<\/p>\n The good news is the clock’s already running. According to the state, natural refilling began at the end of the 2025 construction season. Still, Sierra winters don’t behave the same way two years in a row, so I’d read four to six seasons as a range rather than a promise.<\/p>\n The trout are coming back, too. The Nevada Department of Wildlife moved the lake’s fish to nearby reservoirs during construction, and the state’s completion notice<\/a> says NDOW will restock Marlette with rainbow and Lahontan cutthroat trout when conditions allow.<\/p>\n As for the riders, you can do the whole thing again. Nevada State Parks reopened the Flume Trail and the rest of the west side of the Spooner Lake backcountry in early October, and the state’s completion notice went out on October 5.<\/p>\n","protected":false},"excerpt":{"rendered":" The Flume Trail is pretty much the ride people mean when they talk about mountain biking at Lake Tahoe. You … <\/p>\nSo what was wrong with it?<\/h2>\n
How do you rebuild a dam with a lake behind it?<\/h2>\n
Two summers on a dirt road<\/h2>\n
So when does Marlette fill back up?<\/h2>\n