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:   June 10, 2010

Head of Old River (HOR) Barrier:

The spring Head of Old River rock barrier was not installed this season.  Instead, as in 2009, a Non-Physical Barrier (NPB) was installed.  Installation began April 5 and was completed on April 15.  The operation of the NPB supported the VAMP fish study and includes a determination of the NPB’s effectiveness.  The salmon smolt monitoring was concluded on May 26 at the end of the VAMP, however the NPB will stay in operation through June 15th  in compliance with our NMFS biological opinion to benefit non-VAMP smolts that may still be in the river.

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

Construction of the MR barrier began on May 19.  Due to equipment problems, closure of the MR barrier was delayed to May 24. All flap-gates are in the tied open position, but will be untied in the next day or so (see modeling notes).

Construction of the ORT barrier began on May 10 and the boat ramp was completed on May 13.  Closure of ORT barrier was achieved on June 3 at 8:30 a.m. All flap-gates are in the tied open position, but will be untied in the next day or so (see modeling notes). Crews discovered slight settlement at the upstream boat ramp but the problem did not impair boat ramp operations and settlement repairs were completed on June 7.

Installation of the GLC barrier will begin on June 16 after the removal of the NPB.  The GLC barrier site needs to remain open to allow passage of a large barge/crane that will be dismantling the NPB on June 16. It will take about two weeks to complete the construction.

Water Levels/Water Quality Problem Notifications:  None this week, however South Delta Water Agency alerted DWR of low water levels experienced by the West Side Irrigation District (intake upstream of ORT site) last week.


Modeling results this week compared water levels at Middle River and Old River with and without the flap-gates operation. Modeling results and CDEC data indicated that with the flap-gates tied open at MR and ORT barriers, water levels at Middle River at Howard Road Bridge would be below the +0.3 feet action trigger.  With flap-gates operated tidally at both barriers, the water levels at Middle River would improve and remain above +0.3 feet.  Consequently, DWR discussed the situation with the US Fish and Wildlife Service via the DAT conference call today and initiated action to have the flap-gates at the MR and ORT barriers untied and operating normally as soon as possible.

See attached similation with flap-gates tied open and similation with flap-gates operated tidally.

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: