The Trinity River - Proposed Flow Changes

[ricards]

It might be a short season on the Trinity, just when the bigger wild steelhead, the so-called "canyon fish" start moving up river. The Feds are proposing to raise the flows to 1800 CFS on February 1 through April 22 for the next two years.

https://www.usbr.gov/newsroom/newsre...RecordID=60846

[winxp_man]

I'm curious now if this will improve the fish numbers. Also will the Lewiston lake be able to maintain this flow and still retain water?

[JasonB]

The link didn’t work for me, but I cant help but wonder if this would be beneficial to the fish. 1800cfs is still plenty fishable imo, but I can see where it would put some folks off as it would make some spots no good and it would make the potential holding fish much more spread out. I’ll reserve judgment until I can see a lot more info, but on the surface this doesn’t seem like the end of the world?
JB

[TahoeJoe]

I needed to add https:// to the front of the link to make it work. Looks like ricards has updated the post.

I followed the link from there to the www.trrp.net web pages. The increased flows are part of a plan to restore the Trinity to the pre-dam state. The releases are meant to simulate pre-dam snow melt conditions. Lots of other good stuff on the website - pages of info on gravel bar restoration and gravel replenishment, riparian re-vegetation, etc. I easily killed an hour.

Here's a link to the FAQ on flows, the releases from Trinity/Lewiston won't drain down the lakes as long as the water allocation plan is followed:
http://www.trrp.net/restoration/flows/flow-faq/

Yeah, the higher flows will make it tougher on fishers but, hopefully, it'll make for stronger populations in the future.
--Joe

[Sierra D]

The Smolt migrate out on those spring flows. The bigger and colder they are, the quicker they get out, and the more likely they are to elude predators and survive. I’ve seen amazing charts on the water starved Stanislaus, Tuolumne, and Merced Rivers. They show that every time there are big spring flows, the smolt survival is so much better that in 2 1/2 years there’s a banner run of adults returning. This is mainly about chinook, but if it helps chinook, it’s bound to help steelhead too.

[JayDubP]

The Smolt migrate out on those spring flows. The bigger and colder they are, the quicker they get out, and the more likely they are to elude predators and survive. I’ve seen amazing charts on the water starved Stanislaus, Tuolumne, and Merced Rivers. They show that every time there are big spring flows, the smolt survival is so much better that in 2 1/2 years there’s a banner run of adults returning. This is mainly about chinook, but if it helps chinook, it’s bound to help steelhead too.

Makes too much sense. Recent article on the salmon in the Mokelumne stated salmon smolts are being trucked down river so they avoid the diversion canals and water pumps. plus they are being given a saltier diet for few weeks prior to allow them to quickly adapt to the water in the Delta, SF Bay and the ocean.

It is a good start to a problem that has many causes.

[ricards]

Thanks for providing additional links, Joe. I will not be able to attend the meeting in Lewiston this Thursday, but I would have two questions for Reclamation, if I were there. The first would be: If the biggest threat to salmon and steelhead juveniles is a warming ocean and decrease in food supply, are efforts to restore flood plain and lost habitat on the Trinity, a case of too little, too late? The second question would be: once you have yanked out vegetation and widened the "riparian corridor" what's to prevent seedlings to take hold and new trees (willows) and new vegetation (berry bushes) from sprouting up, if high flows are not maintained? Perhaps the "new norm" for the Trinity should be 1800 CFS and not 300? Anyone out there a biologist, who can weigh in on this?

[ricards]

And, yes, I understand that the increased flows are meant to assist smolt on their way to the ocean. But I believe that the other component of this is to wash out newly-created flood plain.

[JasonB]

Thanks for providing additional links, Joe. I will not be able to attend the meeting in Lewiston this Thursday, but I would have two questions for Reclamation, if I were there. The first would be: If the biggest threat to salmon and steelhead juveniles is a warming ocean and decrease in food supply, are efforts to restore flood plain and lost habitat on the Trinity, a case of too little, too late? The second question would be: once you have yanked out vegetation and widened the "riparian corridor" what's to prevent seedlings to take hold and new trees (willows) and new vegetation (berry bushes) from sprouting up, if high flows are not maintained? Perhaps the "new norm" for the Trinity should be 1800 CFS and not 300? Anyone out there a biologist, who can weigh in on this?

Well as far as the first question, I agree that there are bigger and tougher issues but I don’t see that as cause to not take other actions that would or could be beneficial to our fish. On the second question, you are correct that seedlings would take up root once again if flows were maintained at a steady consistent flow as it was for a few decades. I doubt that the 1800cfs is intended to do much about that, but the May high flow releases are meant as an attempt at a closer to natural hydrograph. Those flows are much higher of course.

I’m certainly no biologist, though I do have a bit of experience chatting with biologists and geomorphologists about the various issues and restoration work being done on the Trinity. While not every singular aspect of each and every decision or action taken by the BOR is unanimously agreed on, they have all been firmly in agreement (so far, of those I have talked with) that the overall restoration efforts were making some very positive improvements in stream health and fish habitat. I have my own hopes and concerns regarding the management of the Trinity river, but overall I always see that the closer to a natural state we get the better nature works; both for reasons we can measure and understand, and for reasons we cannot.
JB

[Fishtopher]

Thanks for providing additional links, Joe. I will not be able to attend the meeting in Lewiston this Thursday, but I would have two questions for Reclamation, if I were there. The first would be: If the biggest threat to salmon and steelhead juveniles is a warming ocean and decrease in food supply, are efforts to restore flood plain and lost habitat on the Trinity, a case of too little, too late? The second question would be: once you have yanked out vegetation and widened the "riparian corridor" what's to prevent seedlings to take hold and new trees (willows) and new vegetation (berry bushes) from sprouting up, if high flows are not maintained? Perhaps the "new norm" for the Trinity should be 1800 CFS and not 300? Anyone out there a biologist, who can weigh in on this?

In response to your first question, it is possible it is too little too late. We can't control ocean conditions though so all we can hope for is restoration to improve juvenile salmonid conditions in the river to better suit them for ocean life. Whether or not that is worth it is a different question.

As for your second question, flows will be variable and designed to mimic precipitation events so most new seedlings will not survive when flows drop and the ones that do would have likely persisted anyways. It should help to alleviate the problems with the thick riparian vegetation that has constricted the river. It will also spread riparian vegetation along a larger area which will create cover for juvenile salmonids at variable flows. Like JasonB said, the spring high flows will scour most of the willows on the floodplain anyways which should also prevent the riparian berm problem on the river.

These new flows should help inundate floodplains which are known to be extremely productive for juvenile salmonids. Studies on the Yolo Bypass have shown this to be true.