The following report on the Temporary Barriers Project is for your information and action, as appropriate.  This report will be transmitted whenever changes occur to the operation of the barriers, and as a result of modeling and/or field monitoring of water levels in the south Delta.

STATUS AS OF:   May 15, 2009

Head of Old River (HOR) Barrier:

The spring Head of Old River rock barrier was not installed this season.  Instead a Non-Physical Barrier (NPB) or “bubble barrier” was installed.  Installation began April 7 and was completed and tested in time for the first of seven VAMP experiment fish releases that began April 22.  This experimental barrier—placed near the channel bottom and extending across the entrance to Old River—uses a combination of bubbles, lights, and sound to guide out-migrating Chinook salmon smolts away from Old River to continue their migration down the San Joaquin River.  Underwater receivers have been installed to detect tagged smolts to study the effectiveness of this NPB.  Preliminary results indicate the NPB significantly improves the number of smolts staying in the SJR over a no-NPB condition.  The NPB will be removed beginning May 26 after the VAMP experiment ends. 

Photos of the NPB are available on DWR’s website at:

Agricultural Barriers (Old River near Tracy [ORT], Middle River [MR], Grant Line Canal [GLC]):

The U.S. Fish and Wildlife Agency Biological Opinion for the installation and removal of the temporary barriers was received May 7 allowing DWR to begin installing the agricultural barriers.  Installation will begin May 18 with work at the MR and ORT barrier followed by the GLC barrier as heavy equipment becomes available.  Installation and cleanup of all work on the ag barriers will take 2-3 weeks. 


Modeling will begin the week of May 25 as installation of the ag barriers advances enough to provide accurate modeling conditions.


These weekly updates are also available for your information on our website:

If you know of anyone else that should be receiving this update, please let me know by email, and I'll add them to the mailing list.  Thanks!

Mark A. Holderman, P.E.
Chief, Temporary Barriers Project and Lower San Joaquin
Bay-Delta Office
California Department of Water Resources
1416 9th St., P.O. Box 942836
Sacramento, CA 94236-0001
Phone: (916) 653-7429  FAX: (916) 653-6077
Cell: (916) 601-6036 E-Mail: