After some relatively chilly spring weather, the Eastern Sierra runoff drama is heating up.
Streams and creeks that were languishing in the “normal” runoff range are starting to gush like Taylor Swift fans seeing their hero in a sequined romper. And, like the dazzling pop star, this year’s runoff season has legs, with most estimates calling for high water and potential flooding well into June.
The remaining Eastern Sierra snowpack remains about as large as the big 1969 and 2017 snowpacks, record years two and three, respectively. The latest LADWP “precipitation” report from May 9 shows the Sierra still holds about 53 inches of snow/water equivalent, or about 235% of a normal April 1 measurement. That’s down from the record tally of 68 inches, which was about 300% of a normal snow year and the new, all-time record. But it’s still right about at the peak of the 2017 snowpack, which hit just over 50 inches.
Total runoff this year is estimated to be about 233% of average, which translates into 1.1 million acre feet of water. The latest estimate from LADWP calls for roughly 350,000 acre feet exported to Los Angeles via the LA Aqueduct. Another 460,000 acre feet will be “spread” in Inyo County; with 167,000 acre feet going into the Owens Lake brine pool in the middle of the lake; soaking up about 100,000 acre feet will be the Owns Lake dust control project and “in-valley uses” for irrigation, town drinking water, mitigation and environmental projects (some pumped groundwater is used for some of those chores).
The past month has showcased LADWP’s ability to move water. The following are the amounts of water released (24-hour average reported on May 17) from LADWP reservoirs: Long Valley Reservoir/Crowley Lake 1,395 acre feet; Pleasant Valley Reservoir, 1,462 acre feet; Tinnemaha Reservoir, 1,339 acre feet. And the clincher; that day the LA Aqueduct sent roughly 1,547 acre feet of water down the pipe. That system-wide water shuffling strategy has been in place since mid-April.
This season’s record snowpack and runoff have already created some eye-popping sights in the Owens Valley. Locals and travelers on US 395 have been getting googly eyes at the sight of water covering the once-dry Owens Lake. Descriptions of the historic return of the massive “lake” have taken on the tenor of, take your pick, a religious/orgasmic/out of body experience – “ohhh, ahhh, yes, yes, yes, OH MY GOD, my life will never be the same.”
Construction crews installing long siphons on the Tinnemaha Dam so more water could be drained from the reservoir was a disconcerting scene and harbinger of too much more water to come.
But for the most part, up to now the big melt has been a slow motion bit of water torture for the past six weeks. Streams were well within their banks for the past month. The Owens River has swelled with reservoir releases. But the onslaught has been delayed. At the May 9 Inyo/LA Technical Group meeting, Eric Tillemans, manager of LADWP aqueduct operations, said, with a sigh of relief, that not all ditches and canals in the Bishop area were filled and flowing because “right now, there isn’t a lot of surplus water.”
(Side Note: the massive amounts of water flowing into and through Inyo County this year have taken the usual edge off the county’s comments and admonitions to LADWP about its annual operations plan. The two traditional adversaries are not exactly hot-tub buddies sharing in a warm moment, but close.)
With summer-like temperatures arriving, streams are picking up steam.
In Mono County, Lee Vining Creek flows went from 38 cubic feet per second (cfs) on April 18 to 71 cfs on May 12 to 185 cfs on May 17. Rush Creek flows have moved in unison with the sunny weather, with flows of 56 cfs on April 18, up to 232 cfs on May 1, dropping to just 115 cfs on May 12 then going up to 288 cfs on May 17.
Those streams feed Mono Lake, which is also rising, hitting an elevation of 6,380 at the start of May. The massive lake can take all the water coming its way, and could rise up to 5 feet, according to LADWP.
Crowley Lake is the star of LADWP’s reservoir show. With minimal stream flows coming into the lake most of the year, the lake level is about 21 feet below capacity as of May 17, as evidenced by the “bathtub ring” around the big pond. Nonetheless, Rock Creek is now running at more than 117 cfs, up from 39 cfs on April 18, and the Owens River is starting to surge a bit, with Hot Creek and McGee Creek also rising.
Bishop Creek is finally picking up the pace, too. On May 17 it was running at 222 cfs, compared to a mild 123 cfs on the 12th and a slow 90 cfs on April 17.
Further south, Big Pine Creek hit 84 cfs May 17, compared to a calm 19 cfs on April 18, and Independence Creek ran at 57 cfs on May 17, compared to 22 cfs on April 18.
While there are plenty of eyes on creeks running through towns, LADWP is also watching the two dozen small, seasonal creeks coming off the Sierra. This spring’s rainstorms proved those dry gullies can turn into gully washers with incredible power.
Indeed, one of the most dramatic visuals of the 2023 runoff season popped up when March rainstorms created a debris flow with enough force to literally wash out a section of the Los Angeles Aqueduct west of Olancha.
Only time will tell if that powerful display of free-flowing water was a one-off bit of bad luck, or an ominous preview of more ugly, wet scenes to come.
(Note: all the data in this story is preliminary and is based on the “real time” data and the LA Aqueduct Northern District Daily Reports, which can be found on the LADWP website.)