Peak flows on Mono Lake’s tributary streams

High-elevation snow is melting in the Mono Basin and we are enjoying quite a show of runoff. The winter of 2022–2023 broke records for snowpack and we’ve been watching that snow gush down Mono Basin creeks. Cool spring and early summer temperatures meant a slow start to the runoff season. Now this week’s heat wave and resultant melt is producing the highest daily flows of the season and likely the biggest peak of the year. Here’s a rundown of the season’s big runoff on Mono Lake’s two largest tributaries.

Rush Creek

On Mono Lake’s largest tributary, flows to the lake have exceeded 800 cubic feet per second (cfs). Think of one cubic foot as a basketball floating by—now imagine 800 basketballs passing you every second!

Rush Creek streamflow is measured between Silver Lake and Grant Lake Reservoir. We expect this week’s peak will be the highest of the season, dwarfing high flows in average and dry years. Mono Lake Committee graph.

Rush Creek’s natural flow is impaired by several reservoirs and dams, from Waugh Reservoir at an elevation of 9,400 feet to Grant Lake Reservoir, just seven miles above Mono Lake. To experience a truly unimpaired runoff peak, those reservoirs must be full and spilling over their dams. High releases from Gem Lake on Rush Creek has contributed to a spectacular Horsetail Falls this season in June Lake.

Horsetail Falls flowing above the June Lake Loop. Photo by Santiago Escruceria.
Rush Creek has flooded the meadow upstream of Silver Lake. Photo by Geoff McQuilkin.

Grant Lake Reservoir has been low for several years. This season’s snowmelt has filled the reservoir, which rose over 30 feet and started spilling on June 7th. We expect the reservoir to continue spilling through this month and into August.

Grant Lake Reservoir began spilling on June 7th this year and will likely continue to do so into August. Photo by Elin Ljung.

Meanwhile, mandatory flows have been delivered around the Grant Lake dam via a pipe and ditch, maxing out the capacity of that infrastructure at over 380 cfs. This flow meets the spillwater in Rush’s natural channel, about a half-mile below the reservoir.

Parker Creek and Walker Creek join Rush one to two miles below Highway 395, each contributing its own high (though relatively modest) flow. From here, Rush’s rising waters spread into multiple channels in its bottomlands, boosting the creek’s nature-based restoration.

Rush Creek’s main channel (right) and smaller side channels to the left and far right, which have been activated by this year’s high flows. Photo by Robbie Di Paolo.

The full flow of Rush comes back together at Test Station Road, all 800 cubic feet per second, then travels the last mile down to Mono Lake.

Rush Creek below the culvert on Test Station Road. Photo by Robbie Di Paolo.

Lee Vining Creek

To witness Lee Vining Creek’s high-elevation streamflows this year, you’ll need a pair of walking shoes or a good bike. Highway 120 West remains closed to cars in Lee Vining Canyon but we have reports of Lee Vining Creek overtopping its culvert and flowing over Saddlebag Road at the junction with Hwy 120.

Lee Vining Creek overtopping its culvert and flowing over Saddlebag Road in the late afternoon of July 3. Video courtesy of Nathan Taylor.
Lee Vining Creek flowing out of Ellery Lake. Photo courtesy of Nathan Taylor.
Photo by Maureen McGlinchy.
Lee Vining Creek flowing high and fast at Aspen Campground. Video by Maureen McGlinchy.
High water near Aspen Campground. Photo by Maureen McGlinchy.

High flows in lower Lee Vining Canyon have caused roaring cascades, closed campgrounds, (above) and complications in streamflow measurements. Lee Vining Creek streamflow is measured just above the diversion pond. The height of the flows has allowed a portion of the creek to bypass the infrastructure of the stream gauge and therefore escape measurement. DWP manages the gauging station and staff are estimating the missed flow.

The majority of Lee Vining Creek flows down the main channel and through the measuring flume to the center-left. When the stream is high enough, a portion of the creek accesses a side channel to the right and bypasses the flume. This water rejoins Lee Vining Creek in the diversion pond about a quarter mile downstream. Photo by Maureen McGlinchy.
The high-elevation snow in Lee Vining Canyon responds to hot daytime and warm nighttime temperatures, evidenced by the peaks in mid-June and early July. These measurements include an estimate of bypassed flow around the gauge. Mono Lake Committee graph.
Lee Vining Creek below the measuring flume. Video by Maureen McGlinchy.

The section of creek below the town of Lee Vining is spreading across channels. The rising groundwater table is the perfect seedbed for riparian vegetation like cottonwood, willow and aspen, furthering the restoration-in-progress.

An aspen, now engulfed by Lee Vining Creek, gets shaken by the high flows. Video by Fiona Travers.

The Lee Vining Creek “crossing” at Picnic Grounds Road is more uncrossable than ever, as the width of the creek has more than doubled.

Picnic Grounds Road at Lee Vining Creek. Photo by Maureen McGlinchy.

Rush Creek and Lee Vining Creek inflow, along with other exceptionally high inflows this season, has raised Mono Lake nearly four feet since December 2022. We look forward to the lake’s continued rise in the coming months as Mono Basin snow continues to melt. But the benefits of a big winter go beyond the much-needed lake rise. Mono Lake’s tributaries, large and small, will use this year’s extraordinary flows to accelerate restoration processes.

Top photo by Elin Ljung: Lee Vining Creek downstream of Aspen Campground on July 9, 2023.


  1. Thanks for this story with its short video clips. I remember playing in Lee Vining creek at the Aspen Campground with my daughter and her buddy years ago. Also I really appreciate the tour Nora Livingston gave me of the Rush Creek facilities and restoration area last October. Keep on saving Mono Lake!

  2. The last photo is the big pullout by the rickety old wood bridge? We parked there and went birding beyond the bridge during the Mono Chautauqua – this is amazing and such great news. thanks for all the videos and photos