[env-trinity] Mainstem Trinity River spawn survey update for November 3 to 7, 2014

[Chamberlain, Charles]

Hello Trinity River fans,
The US Fish and Wildlife Service along with the Yurok Tribe, California
Department of Fish and Wildlife, US Forest Service, and Hoopa Valley Tribe
have another weekly update for our Trinity River mainstem spawn survey
posted on the Arcata Fish and Wildlife Fisheries webpage.
http://www.fws.gov/arcata/fisheries

Our crews mapped 520 redds and 861 carcasses in the Reaches from Lewiston
Dam to Pigeon Point, and Hawkins Bar to Weitchpec.  The graph below is
clipped from our weekly report

[image: Inline image 1]


*Did you know*.... Gravel bars filter water?  Hyporheic exchange occurs in
rivers when surface water flows into groundwater and vice versa.  Gravel
bars and river meanders are places where hyporheic exchange is typically
high.  Among the numerous beneficial attributes of hyporheic exchange is
the ability of substrates and the organisms that thrive within them to filter
particulate matter
<http://odp.trrp.net/Data/Documents/Details.aspx?document=1898>.  This
service may be highly apparent right now in the Trinity River!  The water
currently being released from Lewiston Reservoir is unusually turbid,
perhaps due to recent fall storms and exposed shorelines of Trinity
Reservoir?  Our spawn survey crews this week reported river water
visibility less than 3 to 5 feet immediately downstream of Lewiston Dam.  Water
from Trinity Reservoir destined for the Trinity River first flows through
Lewiston Lake where some suspended particulate matter settles out.  Calm
water has less capacity to carry suspended sediment than turbulent water.  Fine
particulate matter can stay suspended in the water for longer periods, even
as it makes its gradual way through Lewiston Lake.  Water visibility
increased to 5 to 10 feet at Bucktail River Access 6.4 miles downstream of
Lewiston Dam, and to greater than 10 feet at Douglas City 20 miles from
Lewiston Dam and all points downstream!  The fine particulate matter
responsible for reduced visibility at Lewiston is greatly reduced after
flowing through just a dozen or so miles of Trinity River corridor. :)



If you would like to be removed from the blind cc list I use to distribute
this weekly report, please let me know

I'll check in with you next week,
Charlie

Charles Chamberlain
Supervisory Fish Biologist
U.S. Fish and Wildlife Service
1655 Heindon Road, Arcata, CA 95521
http://www.fws.gov/arcata/fisheries
(707) 825-5110
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