LA TAKES THE ‘L’

Los Angeles has “lost” about 76,000-acre feet of Eastern Sierra water over the past 30 years.

The “missing” water might be one of several reasons the Los Angeles Department of Water and Power is so persnickety about taking every drop it is legally allowed to export from the Eastern Sierra. 

In reality, all that water is not “lost” or “missing.” Rather, it is still floating around the Eastern Sierra instead of flowing into the Los Angeles Aqueduct and on to Los Angeles. 

What happened?

The legal landscape at the two lakes at the ends of the LADWP water gathering operation has dramatically changed the department’s water exports. In short, LA is not taking as much water from Mono Basin/Mono Lake and is putting way more water on Owens Lake than it anticipated it would have to when the Inyo-LA Long-Term Water Agreement (LTWA) went into effect in 1992.  

That little gem of information can be found in LADWP’s Draft 2025 Owens Valley Report, on page 72 in the 232-page PDF document, or page 2-23 in the document’s numbering system. 

The page provides a detailed deep dive (sorry) into the history of LADWP’s water gathering and exporting in the Eastern Sierra dating from 1945 to the present. It’s a lot of numbers and estimates, so please be patient. Oh, and you might want to fire up your phone’s calculator, just in case I miscalculated. 

The big-picture example goes like this: in the Pre-Project era (1945-1970), LA Aqueduct exports averaged 322,000-acre feet per year. The Actual Post Water Agreement Averages (1992-2024) show aqueduct exports at 246,000-acre feet per year. 

So, there has been an overall “loss” of 76,000 acre feet (AF) per year of exports since the Water Agreement went into effect. (To put that amount of water into perspective, one acre foot of water is 326,000 gallons multiplied by 76,000 acre feet is 27 billion gallons.)

Here is the breakdown per basin: Pre-Project: 130,000 AF from the Owens Valley; 134,000 AF from Long Valley; and 58,000 AF from Mono Basin, for 322,000 total AF. 

Actual Post Water Agreement Averages: Owens Valley, 100,000 AF; Long Valley 134,000 AF; Mono Basin, 12,000 AF, totaling 246,000 AF. 

The more interesting column of numbers is the Projected per Water Agreement (Projected per LTWA) estimates. LADWP estimated exports would actually increase by 33,000 AF to about 355,000 AF (Owens Valley, 190,000 AF; Long Valley 135,000 AF; Mono Basin, 30,000 AF.) The large jump in Owens Valley exports that never materialized is explained below and visible during a visit to Owens Lake which looks more like a lake than the dry, dust-blasting sinkhole of days gone by. 

The second obvious glitch in the estimate and the reality is Mono Basin’s contribution, which plummeted due to the 1994 State Water Board decision limiting LADWP exports from the basin based on the level of Mono Lake. 

Prior to that legal limitation, LADWP estimated (in 1992) it would take about 30,000 AF of water from Mono Basin, a reduction from the 58,000 AF “historic” export levels. Where did that 30,000 AF number come from? A footnote declares that is the amount of water LADWP will be allowed to export once the lake hits the “management level” of 6,392 feet above sea level (the lake is currently at 6,282 feet, which allows 16,000 AF of diversions). All those numbers, real and projected per LTWA, are actually low. Another footnote notes the startling fact that prior to the 1994 court decision, Mono Basin exports averaged 81,000 AF a year. Egad. 

Back in reality, since 1994, diversions from Mono Basin have ranged from 4,500 to 16,000 AF a year, resulting in a minimum loss of about 42,000 acre feet of water flowing into Inyo County and then the LA Aqueduct. 

Bingo Number One. 

Our search for more “missing” water now moves to Inyo County. 

Irony arrives with us. 

The Pre-Project “Owens Valley Water Supply” is pegged at 346,000 AF. Projected per LTWA supply jumps to 435,000 AF, and actual averages hit 398,000 AF of water. So LADWP actually “found” another 52,000 AF? 

Sort of.

Before 1970, LADWP had a limited groundwater pumping operation, showing just 10,000 AF a year. But completion of the Second Barrel of the Aqueduct in 1970 prompted a huge surge in groundwater pumping and reductions in the amount of irrigated land and irrigation in Inyo County. That sparked the lawsuits by Inyo County, Sierra Club, etc., that led to the Long-Term Water Agreement. The agreement, however, gave LADWP legal “permission” to continue its groundwater pumping, with some limits. 

Long story to get to the Projected per LTWA estimates, which saw pumping go from 10,000 AF to a huge 110,000 AF. Runoff from Owens and Round Valley was estimated to jump 18,000 AF to 310,000 AF. Another 15,000 AF came from “flowing wells,” commonly called artesian wells. That was a significant drop from 44,000 AF in the Pre-Project days, since more groundwater pumping dried up the artesian wells. All that added up to 435,000 AF. Hitting that projected total did not happen. 

Okay, take a breath. 

The Actual Averages since the Water Agreement went into effect, show Owens and Round Valley runoff were essentially the same or just a tad higher than Pre Project years – right at about 300,000 AF. Flowing wells increased to 31,000 AF. The big gain, however, was groundwater, which has averaged about 70,000 AF a year since 1992. 

To recap thus far: LADWP is exporting less water from Mono Basin, while shipping out a bit more water from Inyo County, thanks to groundwater pumping.  

So where is our mysterious “lost” water?

Right there in the line with the probably unintended but quite revealing title, “In-Valley Uses & Losses.” 

Let’s start at the beginning. The Pre-Project In-Valley uses on LADWP land were only 82,000-acre feet from two items: Irrigation, 62,000 AF and Stockwater, Wildlife and Recreation, 20,000 AF. The estimate for what would happen After the Water Agreement jumped that number up to 110,000-acre feet and included water mandated for Enhancement/Mitigation Projects, the Lower Owens River, etc. And that is about where the In-Valley water uses have remained since 1992, averaging about 100,000-acre feet a year.

Here’s the kicker in the “Other O.V. Uses & Losses.” Those include water for Indian land, private lands, conveyance losses, aquifer recharge (spreading), evaporation and operational releases. Then comes the Big One: water for “dust mitigation for Owens Lake.” 

The Pre-Project and Projected per LTWA totals for those Other OV Uses held steady 135,000 a year. 

Then came the Owens Lake lawsuits and mandated dust mitigation work, which cost LADWP about $2 billion. About 50 square miles of the lakebed have been “treated” using gravel, vegetation and water shipped in from the LA Aqueduct for shallow flooding. 

The shallow flooding has increased the Actual In-Valley Uses and Losses to an average of 197,000-acre feet a year. That’s roughly 62,000 additional acre feet of water than LADWP used for In-Valley uses before the Water Agreement and dust mitigation on the lake. 

Bingo Number Two. 

Add in the “lost” 42,000 AF from the Mono Basin, and LADWP is lucky that only 76,000 AF has gone “missing” over the last 30 years. 

That’s a long, torturous route to arrive at this conclusion: Owens Lake and Mono Lake are “winners” in the Eastern Sierra’s “lost water sweepstakes.” 

 

Jon Klusmire of Bishop would get into the looming impacts of climate change on the Eastern Sierra snowpack and runoff, but he’s tired and his calculator is screaming for mercy.