DELTA OUTFLOW HOVERS AROUND ZERO, MAKES WATER TRANSFERS RISKY; INCREASES LEVELS OF SALT IN ESTUARY

By Patricia McBroom
      
       There is no fresh water flowing out of the Delta on this early July day in summer and hasn't been since May, new data is showing. The only water surging in and out are the salty tides, which continually threaten fish and fresh water pumps serving people throughout the state.

USGS acoustic Doppler devices near Rio Vista bridge
keep track of fresh water outflow from Delta channels

      This is the apparent condition of the Delta, according to state-of-the-art flow monitors operated by the USGS in four locations near Rio Vista and Brannon State Park (among others), where fresh water meets salty and becomes brackish. 

       Official estimates of outflow, however, calculate that about  4,000 cubic feet per second (cfs) of fresh water is flowing into the Bay – admittedly low, but not zero, which would have important implications for managing water in this drought. State-generated outflow estimates are not based on the above USGS monitors, though it has been obvious for at least a year that there is a significant difference in dry years between the two methods of calculating flow.

Small Differences Matter During Drought

      In wetter years, a small disparity such as 3,000-4,000 cfs would not amount to much. This year is different. Drought is taking a huge toll in both northern and southern parts of the state. In the usually wet north, streams and rivers are near dry. The meager snowpack in the northern Sierras hit its runoff peak in April, not July, as usual. Ground water tables are sinking, not just in the San Joaquin Valley, but in some northern counties as well. Farmers throughout the state with junior rights have been ordered to stop diverting water for their thirsty crops.

      Under these conditions, sales of water from north to south – normal at this time of year –become problematic, even when the sellers are willing. And the condition of the Delta, through which the transfer waters must flow, is critical.

Suits Aims to Stop Transfers

Biostatistician Thomas Cannon challenges State outflow
estimates in environmental suit. Credit: Patricia McBroom

      Hoping to stop water transfers of 175,000 acre feet, approved by the U.S. Bureau of Reclamation this spring, two environmental organizations have filed suit in federal court. They requested an expedited hearing to halt the transfers that are scheduled to begin this month. Plaintiffs charge that the Bureau did not do a proper environmental analysis before approving the transfers, and the flow monitors maintained by the USGS in the Delta are poised to play a staring role in the case.

      “Their totals (measuring delta outflow) have been near zero since May,” said Thomas Cannon, a biostatistician whose work is cited in the lawsuit by the California Sportfishing Protection Alliance and AquAlliance. I've never seen it this salty up here,” said Cannon on a recent day in the Delta, waving his arm toward the docks at Brannon State Park.  Based on his analysis, the suit charges that the dayflow method used by State and Federal water officials “grossly overestimates actual Delta outflow” during dry years.

 USGS technician repairs an outflow monitor
at Three-Mile Slough in June.
Credit: Patricia McBroom

      If the outflow is truly as low as the USGS monitors indicate, it means that salt water is constantly threatening to move up the estuary and that a number of fish species, including the iconic longfin and delta smelt, are at risk of being carried into the export pumps which carry water to the south of the State.

Accuracy of USGS Monitors Challenged

      Difference, however, does not establish worth. The man in charge of water operations for the State Water Project in California's Department of Water Resources, John Lehigh, challenges the idea that USGS monitors are more accurate than state estimates.  “I have seen no evidence that would lead me to conclude that this estimate of outflow (using USGS monitors) is more accurate than the one used now.” said Lehigh. He added that if someone thinks he has a better way to measure outflow, that person should bring the issue to the attention of the State Water Board. So far, no one has done that, he said.

      Lehigh also questioned whether the monitors located in the lower Delta, closer to the Bay, can truly detect outflow in the presence of tidal flux. Outflow in drought conditions (3,000 cfs, for example) is miniscule compared to the huge tides (150,000 cfs or more) that daily wash in and out of the lower delta.

Science panel Validates New Outflow Estimates

      Apparently, USGS scientists have been able to account for the tides, because a report to the Delta Science Program in February demonstrated that last year's salinity levels in the Delta matched the USGS outflow meters. Not so the estimates used by the state (called NDOI for Net Delta Outflow Index), which judged outflow to be more than twice as high as the USGS monitors in the fall of 2013.
 “The NDOI estimates appeared to be clearly incorrect,” said the science program's final report (page 15) released in May. The report went on to say that Delta outflow did not meet minimum standards last year and questioned why the better outflow measures are not being used now.
     For this blog, a member of the expert outflow science panel, retired USGS engineer Pete Smith, calculated the difference between the two measurements for May and June this year (see graph). 

By official estimates, fresh water outflow from the Delta is about 4,000 cfs; USGS monitors show that outflow to the
Bay vacillated between minus 6,000 cfs and plus 6,000 but the average for May and June was close to zero.
Graph by Pete Smith

                        The same disparity that was evident in 2013 showed up again this year. NDOI estimates were way higher than outflow as measured by USGS monitors. Whereas California officials believe outflow in the Delta is around 4,000 cfs this summer, the actual figure measured where the Delta meets the Bay is about zero.  In light of these findings, the State Water Board will be looking at "possible changes in determining outflow," said SWRCB engineer Rick Satkowski.

Delta Smelt Not in Normal Habitat

      So what does this complicated science all mean?

      One possibility is that famous Delta fish species – the delta smelt and longfin smelt– could go extinct this year. Smelt follow a salt line called the X2 because they prefer brackish water. Normally the smelt are in Suisun Bay by the end of June, but this year they seem to be still swimming around in the central Delta, near Brannon. In addition to using possibly inaccurate measures of outflow (thus not releasing sufficient water from the reservoirs), the State has also relaxed its salinity standards this summer, bringing the X2 boundary further upstream. This means the precious few smelt that are left after years of decline are now directly in line of the pumps that take water south.

      “This year, the only delta smelt anyone's been able to find are in the Delta,” said Michael Jackson, an environmental lawyer who has filed public trust suits against the State in past years, but is not involved in this one.

Four USGS stations monitor outflow where Delta water enters the Bay;
official outflow monitors are located further upstream toward Sacramento
and where rivers enter the Delta.

      “Because there is no outflow, the only flow will be toward the pumps. Since transport goes right through the area where the last smelt are, it seems like we have put a tremendous amount of money and pain into preserving the fish, only to end up exterminating the species this year.”  Jackson said there is nothing in the Bureau of Reclamation's environmental report on water transfers that recognizes the threat to delta smelt.

Northern Communities also at Risk

      Nor is there anything that recognizes the danger to communities, farms or ecology in California's north, said Barbara Vlamis of AquAlliance, one of the plaintiffs. She said that the Bureau has simply asserted that no environmental harm will be done to northern areas selling the water, calling the assessment a “cheap and shoddy version of NEPA” (National Environmental Policy Act).

“Why are we selling water out of the north when the area will be rationing this summer? By percentage of normal precipitation, the north has been hit harder this year than the south,” said Vlamis.

      (Bureau officials have been making “temporary” one-time transfer decisions for years, thereby obviating the need for a full-scale environmental analysis on any one of them. The environmental suit is challenging this practice.)

Salt Levels Due to Affect Pumps

      Another thing zero flow means is that salt contamination of pumps that bring water to people in Contra Costa County, as well as southern parts of the State, will climb throughout the dry summer months. When salt rises too high, however, the Contra Costa Water District can dilute it with fresh water from Los Vaqueros Reservoir, so there is no imminent threat to urban areas. Too much salty water in the southern Delta could, however, stop the water transfers regardless of the outcome of the pending legal case.

      Who gets the water – if it goes through – is unknown. Buyers and sellers are anonymous until contracts are written. But if history and rumor are any guides, most of the water is destined to reach Westlands, the wealthy corporate farmers in Kern County, known far and wide for their political muscle in bending state and Federal policies to their private needs. And that's a shame. It is bad enough that these toxic lands, which release selenium into the waterways, get watered in wet years. It's a travesty when they get to use water during a drought like this – water that is critically needed to save the ecosystem and hold the salt at bay for the rest of us.