The plug has been pulled out of the bottom of the Owens Valley plumbing system and the spigot is wide open.
The Los Angeles Department of Water and Power has started running the LA Aqueduct at full capacity to prepare for the inevitable waves of runoff from an Eastern Sierra snowpack that hit a record of about 307% of average.
The snowpack peaked around the first of April, but cool weather and no new, big storms since then have given LADWP some breathing room to prepare for the record runoff.
One of the department’s first moves earlier this year was to divert a huge amount of water onto the Owens Lake. That, combined with some drenching rainstorms, created the impression that the lake is once again “full.” Although there is more water in the lakebed than since the record runoff in 1969, it is still far from full.
Officials from LADWP noted earlier this year that the lake could absorb about 15,000 acre feet of water without damaging its $2 billion dust control infrastructure on the edges of the lake. There has been no recent estimate on how much water has been released on the lake. However, for more than a month, huge amounts of water have been sent down the Lower Owens River. The LORP mandated water flows are 40 cubic feet per second, but there have been flows in the 200 cfs range, with some peaks at about 400 cfs when the aqueduct was out of service due to a break. That amount of water was “spread” in various locations on the valley floor in between Aberdeen and Lone Pine.
But enough water went onto the lake to basically cover the “brine pool” with water. The brine pool is the massive area in the middle of the lake with no dust control work on it. The LADWP dust control effort covers the southern, western and northern edges of the lake, not the middle, and encompasses about 50,000 acres of lakebed. That’s about half of the lake.
In 1969, now the second highest snowpack on record, the lake actually flooded. There was no LORP and Tinnemaha Reservoir overflowed, overwhelming the capacity of the Aqueduct, which was still just one “barrel.” The lake flooding washed over the Pittsburgh Paint and Glass (PPG) soda ash mining operation on the lake. The company sued LADWP. The big, rusted silos on the west side of the lake are what’s left of the PPG plant, and that is also where the water this year is most visible.
This January, when it was apparent that the snowpack was heading for record territory, LADWP dramatically increased water exports though the LA Aqueduct.
The department originally planned to export just about 19,000 acre feet from January to April 1. Instead, it sent about 60,000 acre feet down the aqueduct. That brought its total exports for the 2022-23 water year to about 98,000 acre feet, instead of the 58,000 acre feet as it first proposed.
Even higher flows are now taking place.
The aqueduct exports have ramped up during April, which is the official start of the “water year.” By April 19, about 18,663 acre feet of water had been sent down the two “barrels” of the aqueduct.
That total could actually double by the end of the month.
Starting on April 16, about 1,507 acre feet a day went south. That figure has remained the same through April 19.
That flow is close to the full capacity of the aqueduct. The first “barrel,” completed in 1913, can carry 485 cubic feet per second, while the 1970 second “barrel” has a capacity of 290 cubic feet per second.
Since the 16th, the first barrel reached 480 cfs, while barrel two was at 280 cfs.
Those flows translate into 1,507 acre feet a day.
It will take all that water running for most of the rest of the year to hit the newly announced export target for the aqueduct.
The aqueduct is projected to deliver about 130 billion gallons of water to Los Angeles (more than 400,000 acre feet), which is potentially enough to meet up to 80% of the city’s water demand for a year which is enough to supply water to more than 1 million households, according to an LADWP press release quoting Martin Adams, LADWP General Manager and Chief Engineer.
(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.)