San Joaquin River DOTMDL -- Technical Working Group

Channel fix nears. Agencies fight harmful oxygen levels in water

Stockton Record - July 09, 2004
By Audrey Cooper

SACRAMENTO -- Central Valley pollution cops appear on the brink of averting the frequent fish kills caused by stagnant, fetid water in the Stockton Deep Water Channel.

Regulators are poised to attack the artificially low levels of oxygen in the channel, where fish often suffocate and die in large numbers. Members of the Central Valley Regional Water Quality Control Board are expected to resume a public hearing on the issue today in Sacramento.

The plan, which is at least five years in the making, has been met with reluctance from several groups, including the city of Stockton, the Port of Stockton and the myriad agencies that suck drinking-water supplies from the Delta. Each group says the other should take most of the responsibility for the oxygen-depletion problems.

Low oxygen levels have been a problem in the channel for at least the last three decades. The water is robbed of oxygen when ammonia and algae drift down to the channel. There, the river bottom drops to a depth of more than 30 feet, and the water slows down. Algae sink to the bottom and decompose, a process that sucks oxygen out of the water. Ammonia, coming from either the Stockton sewage-treatment plant or upstream farms, is the other major cause of oxygen depletion.

Finding a fair way to fix the problem has baffled water experts for years. If the channel never had been deepened, oxygen levels probably would be fine. And if no pollutants were discharged into the river, the fish probably would breathe easily. If a greater volume of water flowed down the river, oxygen levels probably also would be fine.

So who should be made to fix things?

Good question, said Mark Gowdy, an engineer with the water board.

"The crux of this problem is that each of those factors could be 100 percent responsible. By removing one factor, you could solve the entire problem. But that's not the most fair thing to do," he said.

The result is a plan that puts nearly equal weight on the three factors. The Port of Stockton and the Army Corps of Engineers, which first dredged the channel, are expected to study the problem and think about ways to pump more oxygen into the waterway. Agencies that take water from the Delta could be told to give some water back to bolster river flows. And the agencies responsible for the pollution - such as the city -- also could be held accountable.

"The river has suffered enough. It's time to get on with it. This plan might not be perfect, but it's probably the best we're going to get," said Bill Jennings, head of Stockton-based DeltaKeeper, who spoke on behalf of several environmental groups.

Bob Murdoch, the assistant director of Stockton's Municipal Utilities Department, said he generally thought the proposed oxygen plan was fair. Last month, work started on a $42 million upgrade to the city's sewage-treatment plant. Those upgrades, funded by Stockton ratepayers, will cut the ammonia discharged into the river by more than 90 percent.

Murdoch said he worried that the city could be ordered to do even more to solve the oxygen problem.

"I worry that we may be penalized, and the city will be forced to take on a disproportionate burden if others don't step up to solve this," he said. #

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