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:   September 1, 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 were installed to detect tagged smolts to study the effectiveness of this NPB.  Preliminary results indicated the NPB significantly improved the number of smolts staying in the SJR over a no-NPB condition.  The NPB was removed beginning late May and was completely removed as of June 4.

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

The MR and GLC agricultural barriers are operating tidally.  The ORT barrier have had all nine culvert flap gates operating tidally since August 24.  On September 1 three culverts will be tied open in advance of the upcoming spring tide.  We will continue to operate the ORT consistently by tying open three culverts about 3 days prior to a spring tide and untying these culverts about three days prior to a neap tide (to protect water levels).  Operations of the culverts may change depending upon conditions.


Modeling results are attached.  Actual water levels are above the trigger levels (0.0 feet MSL at Old River and Grant Line Canal barriers, 0.3 feet MSL at Middle River barrier), and should remain that way through the modeled period.

Click here to see modeling outputs


The GLC barrier culverts are in need of repair and are not operating to their fullest potential (some leakage and poorly sealing flap gates).  DWR staff will be diving the barrier to determine the extent of repairs with the intent of completing repairs by the 2010 season.

DWR has applied for permits this summer to allow raising the weir height at the MR barrier an additional one foot.  This would not change the barrier footprint, but would potentially provide improved circulation and water quality upstream in Middle River and downstream in Old River.  It appears unlikely that this change will be permitted in time for the current irrigation season due to the need to prepare additional documentation required by Federal regulatory agencies before review and permitted can be completed.

Due to “Furlough Friday’s” on three of four Fridays each month, the TBP weekly update will go out on Mondays until further notice.

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: