Home
Field Notes
 
U.S. Fish & Wildlife Service
Field Notes Entry   
STOCKTON FWO:Water Tour for California Science and Technology Policy Fellows Program
California-Nevada Offices , December 3, 2009
Print Friendly Version
Aerial view of the Delta Cross Channel and the Sacramento River in the Sacramento-San Joaquin Delta. (photo: U.S. Geological Survey) 
Aerial view of the Delta Cross Channel and the Sacramento River in the Sacramento-San Joaquin Delta. (photo: U.S. Geological Survey)  - Photo Credit: n/a
Presentation at the Delta Cross Channel for the California Science and Technology Policy Fellows Program (photo: Donna King, California Council on Science and Technology)
Presentation at the Delta Cross Channel for the California Science and Technology Policy Fellows Program (photo: Donna King, California Council on Science and Technology) - Photo Credit: n/a

by Pat Brandes, Stockton FWO
On November, 20th, Fish Biologist Ms. Pat Brandes of the Stockton Fish and Wildlife Office (STFWO) briefed students from the California Science and Technology Policy Fellows Program on the role of the Delta Cross Channel (DCC) on water conveyance and juvenile salmon survival through the Sacramento-San Joaquin Delta.  The briefing was part of a water tour of the Delta hosted by the Sacramento Region Water Forum.  The group was introduced to California Water and how it flows by Jeff Loux, Center for Collaborative Policy (CCP) at Sacramento State.  They were also given an overview of recent water legislation, by Sam Magill (CCP).  The group also got a presentation on the water forum agreement and collaborative policy making prior to visiting the Freeport Regional Water Project and the Delta Cross Channel.   

Ms. Brandes explained to tour participants that the Delta Cross Channel was built in the 1950’s by the U.S. Bureau of Reclamation to facilitate the movement of Sacramento River water through the interior Delta, via the Mokelumne River, to the south Delta for export purposes.  Ms. Brandes discussed the general life history of Chinook salmon in the Sacramento River basin, and the importance of the Delta to Chinook salmon in the Central Valley.  Adult Chinook salmon swim upstream through the Delta to spawn in the upper rivers.  The juveniles must migrate downstream through the Delta to reach the ocean.  Ms. Brandes explained that the Sacramento River basin is unique in that it has four races of Chinook salmon; winter run (listed as endangered by the Endangered Species Act (ESA)), spring run (listed as threatened by the ESA) and fall and late-fall runs (species of concern). 

Ms. Brandes’ presentation focused on the results of studies conducted by the STFWO on the impact of the DCC on juvenile salmon survival through the Delta.   Early studies using coded wire tag mark and recapture technology showed that survival is lower for juvenile salmon released into the interior Delta relative to those that migrate downstream via the main stem Sacramento River.  These results indicated that the DCC may contribute to lower survival of out migrating juvenile Chinook salmon by allowing a greater proportion of fish to be diverted into the interior delta.  In recent years the STFWO has been using acoustic tag technology to more accurately determine how fish are splitting at various junctions in the Delta, and at the Delta Cross Channel and Georgiana Slough specifically.  This relatively new technology allows survival for specific routes to be estimated.   As a result of the early coded wire tag work done by the STFWO the DCC gates have been closed during periods of high abundance of out migrating juvenile salmon.  Using the acoustic tag technology we have found that closing the DCC gates does not always provide as large a benefit as has been assumed in the past.  This is due to a greater proportion of the tagged salmon entering the interior through Georgiana Slough with the DCC gates closed.  

Many of the students asked questions and were very interested in the information presented.  Sarah Foley, Director of the Water Forum later said that for most of the students “the concept of the Delta and the fish passage issues did not click until they stood there and listened...”  Mrs. Foley also mentioned that the professor overseeing the group remarked that until this visit to the Delta Cross Channel, he had not understood the complexities of the Delta.


Contact Info: Patricia Brandes, 209-946-6400 X308, Pat_Brandes@fws.gov



Send to:
From:

Notes:
Find a Field Notes Entry

Search by keyword

Search by State




Search by Region


US Fish and Wildlife Service footer