High flows coming to Owens Gorge – what about fish and their habitat?

By Deb Murphy

The 500 cubic feet per second flows scheduled for the Owens River Gorge in late June have been postponed until later this month. But the impact of flows 10-times greater than what has been released hasn’t been postponed. What about the fish and their habitat?

According to California Fish and Wildlife biologist Steve Parmenter, the penstock between the Middle and Lower Gorge Power Plants has to be dried up for safety reasons as Los Angeles Department of Water and Power fix a mechanical problem. All this precedes the construction of a flume, scheduled for September, to begin restoring flows in the length of the gorge.

Parmenter is the go-to guy for trout in the Gorge; he’s been around since the litigation in 1991 that resulted, 24 years later, in putting water back in the once bone-dry Gorge.

“Brown trout need three things,” he said in a phone interview. “Cool, clean water, deep pools, more than three feet and gravel riffles,” providing a smorgasbord of aquatic insects. All of the above could improve with the planned flows.

That assumption isn’t theoretically. According to Parmenter, back in 2003, LADWP ramped up flows to 700 cfs in the Gorge over a period of a few days.

Once deep pools had filled in with sand, the riffles had become sand clogged. All that changed with the high flows. “The pools were scoured out,” said Parmenter. “The flows turned over the gravel and flushed out the sand.” He called the comparison between the 2003 flows and the proposed July flows as good, but not perfect.

The duration of this year’s flows is far longer, roughly two months compared to a few days. But, the mathematics of stream power indicates the proposed 500 cfs flows don’t have near the power of those in 2003, according to Parmenter.

“Big flows for months down a channel are good for habitat,” he said. “That’s not scientific, that’s anecdotal.”

So much for trout habitat, what about the trout?

“Fish do a pretty good job taking care of themselves,” Parmenter said. “The flows are high, but not out of the natural range. Fish hunker down and weather the storm.”

“With stabilized flows, the river loses its structural diversity,” he said, “holes fill in, flows across gravel riffles are slower.”

Parmenter noted the gorge has been either dry or subject to low flows for decades. There’s an obvious comparison to the Lower Owens River where efforts to restore an actual river have been stymied by controls.

Again, anecdotal evidence says the fishing experience could improve after the high flows. A few years after the 2003 release, Parmenter got a calls from anglers asking “what did you do, the fishing is great” in the Gorge.

Not everybody is convinced, however. Phillip Anaya’s concern has to do with the trout’s food source. “A big release will disrupt the hatch,” he stated in an e-mail, “washing out the hatch, limiting the food the trout eat.” Anaya and others want to see an environmental analysis done before the Gorge ramps up to 500 cfs.

 

, ,

7 Responses to High flows coming to Owens Gorge – what about fish and their habitat?

  1. M Anderson July 10, 2018 at 4:58 am #

    The 500 CFS flows “have been postponed until later this month” So when will the high flows actually start?

     
    • Trout Junky July 10, 2018 at 1:19 pm #

      when LA says they need the water..They have a ton of new homes with New Water Meters.
      Let it Flow

       
      • Rick O'Brien July 10, 2018 at 10:29 pm #

        If the City of Los Angeles would spend the money on a de-salinization plant, the Owens Valley could be green again, all the way to Ridgecrest (and beyond!)

         
        • Bob July 11, 2018 at 10:46 am #

          They take the cheap water first. Please get this through your head before posting about desalination. I suggest making Eastern Sierra water more expensive if you want to see change

           
          • Rick O'Brien July 12, 2018 at 9:35 pm #

            And exactly HOW do you make Eastern Sierra water more expensive when the city of Angels OWNS the water already ? There will be a time in the not too far off future that the entire west coast will be covered with de-sal plants . What do you suggest we do when Lake Mead goes dry in 10 years. Like it or not, that’s where we’re headed.

             
  2. Brett July 11, 2018 at 9:13 am #

    If Mr. Anaya wants to study the effects, why not look at the East Walker River? Every year flows drop to virtually nothing. When irrigation season starts, flows routinely climb to 500 cfs or more. Still, some of the best tailwater fishing in the country.

     
    • Philip Anaya July 11, 2018 at 3:09 pm #

      The East Walker is a very different river than the Gorge. It is wider it has less gradient and the flows have been year to year fairly consistent and I do not know the last time there was a 500cfs flown in the Gorge. The high flows for a limited duration less than 1 weeks works into the lifecycle of the hatch. As you might know Mr. B may fly eggs attach to rocks and stone for about 2 weeks before they hatch. They are fleshy, like eggs tend to be and vulnerable . They develop a hardened case and when flows reach velocity the rocks and stones can roll and smash the developing hatch. This hatch cycle if the duration and intensity of flows are long term and forceful as proposed for this “emergency” can be disruptive and diminish the aquatic food for the trout . 500cfs in the Gorge has a greater velocity and force as the steam bed is much more defined, smaller and narrower than the East Walker. One of the best reads for a trout fisherman is Dave Whitlock’s Guide to Aquatic Foods .
      As an alternative how about a short term repeated cycle of flows lets say 16 days starting at 150cfs increasing by 50cfs each day up to the 500 cfs and then decreasing 50cfs each day back to 150 cfs and then repeating the cycle till the work is completed . Maybe this would benefit the hatch, the trout, the stream and really the least of my concerns a continued water supply for the thirsty millions in LA. DWP can always purchase water for Los Angeles from the California Aqueduct (Metropolitan water District) to make up for any short falls .
      The trout never can stop swimming . Why would anyone want to stress them out with washing them out of the Gorge and killing off their food chain . Did they not learn by now that messing with Mother Nature always bites .DWP has yet to file a CEQA document for this so called “emergency” even a minimal “Notice of Exemption”. Who is standing up for CEQA. The DWP is currently under sanction paying daily fine or so they should be, for their non performance in the Stipulation and Order 2014 , “Watering the Gorge” agreement with Mono and the California Fish and Wildlife, so this is a very complicated issue and as usual with DWP, they not doing what they are required and to do and are not doing what they agreed to do in the Gorge. Add to that the issue of DWP threatening Mono Rancher’s water and the solution to all of this becomes very complicated and not just about trout and the aquatic foods that they eat.

       

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.