Delta Flows....
"Question:
With all of the water exported south, don't we kinda keep the delta artificially fresh now? Specifically speaking to salmonids, does a saltier delta hurt smolts or can they still use it before heading out?"
John,.... I'm not sure what keeping the Delta fresh means(??) I guess you could say that fresh water outflow or salt water intrusion freshens the Delta?? At times, when in-river flows are high and tidal activity is low, fresh water pushes the salt water back and when tidal activity is high and in-river flows are low, salt water intrusion occurs. This is overly simplified.
Now comes the artificial part. Add into the equation dams on the San Joaquin River and all of it's tributaries (save one) reducing in-river flows to the point where sections of the San Joaquin run dry during parts of the year and dams on the Sacramento River and it's tributaries each controlling releases into the system, you get artificially median flows over the course of a year (unless drought conditions impact that flow regime as they have recently). All of this creates un-natural in-river flows.
Now add in the CVP/SWP pumps at Tracy. These pumps are so powerful that when they are in operation at capacity, can reverse in-Delta outflows from their natural route. This impacts/confuses the route that migrating Salmon choose to follow into their natal rivers/streams. In the case of the San Joaquin flows are non-existent at critical times blocking migration altogether or polluted with AG insecticides/pesticides when water is available. The current hearings by the State Water Resources Control Board is about increasing flows to address this problem. For other fish species this artificial changing/mixing impacts the spawning habitat of fish like the Delta Smelt and other Delta species. Then there's the problem of predation (big fish eating little fish, etc.) and pelagic organism decline. I'm not even going to try to address the anticipated impact of the proposed Waterfix (tunnels) Project....
This really doesn't answer your question about whether smolts being impacted by a saltier Delta but it's not entirely about whether Salmonids are impacted, to me. It's about whether any/all species (communities, farmers, fish or animal) who live in the Delta are impacted negatively.
All of this stuff should be discussed by someone/organization with more knowledge on the subject than me.
Last edited by Darian; 12-29-2016 at 01:05 AM.
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