A Delta smelt. California Department of Water Resources.
More and more worried about the fate of the diminutive Delta smelt, federal wildlife officials are requiring cuts in the amount of water that can be pumped south from the estuary starting Friday.
While you often hear how smelt have crimped the state’s water supply — and they have, in the past — this is the first time since the winter of 2013 that mandatory restrictions have been put in place.
The action is sure to touch a nerve down south, since runoff from recent storms is needed badly for parched cities and farms.
It’s worth noting, however, that Friday’s cuts are not as stringent as some scientists had recommended. The Smelt Working Group, an advisory science team representing multiple agencies, called for stronger protections to be put in place, citing in part the record-low number of fish.
“Any level of salvage observed at either (pumping) facility will be of concern,” the group said in its weekly report.
It is a cruel irony of California water that the storms we so desperately need are also more likely to draw imperiled smelt toward the deadly pumps in the south Delta, which makes it harder to take advantage of those storms from a water-supply perspective.
How does this happen? Rainstorms wash sediment into rivers, particularly the Sacramento, which then rolls muddy and swollen into the Delta.
If the pumps down near Tracy are running, some of that muddy water is drawn further south. Problem is, the smelt tag along because they like muddy water. It helps them hide from predators.
State pumping plant in the south Delta. California Department of Water Resources
They follow the muddy water until they’ve wandered dangerously close to the pumps, which are so powerful that the Old and Middle rivers in the south Delta actually run backward.
Thus, the problem we have today.
No smelt are known to have actually been “salvaged” at the giant pumps this year, according to the Smelt Working Group, but the scientists recommended reducing “reverse flows” to -2,000 cubic feet per second anyway. That’s because they’ve found smelt not far away in the San Joaquin River, and because they’re concerned that impending storms will draw smelt even closer.
Smelt are so precariously perched on the edge of extinction that very few can be lost to the pumps this year, under a disputed 2008 biological opinion intended to protect them. The limit, in fact, is just 56 smelt this year.
So, waiting for a few to actually show up at the pumps before reducing reverse flows would be risky, the advisory group said.
“Members are concerned that just a few fish detected in salvage will be problematic,” the group wrote after its most recent meeting earlier this week.
A regional director of the U.S. Fish and Wildlife Service ultimately rejected the recommendation to reduce reverse flows to -2,000 cfs, saying in part that the muddiness of the water in Old River might be related in part to tides, and that conditions may not be as poor as believed.
But certainly, there is cause for concern, Fish and Wildlife found.
And so the agency did decide, based on a proposal from the state and federal water agencies that operate the pumps, that reverse flows should be temporarily reduced to -3,500 cfs. That’s down from about -4,396 cfs as of last Sunday, and down from more than -6,000 cfs in late December.
As conditions change, the decision could be reevaluated as early as next week.
Bottom line: It’s once again time to walk the tightrope of water supply vs. species protection. If pumping restrictions like this continue throughout our El Nino-fueled winter, expect to hear plenty down south about large volumes of “lost” water. And if smelt show up at the pumps, expect to hear plenty in the Delta about the likelihood of a lost species.