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:   October 1, 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 and the NPB stayed in operation to benefit non-VAMP smolts through June 15th in compliance with our NMFS biological opinion.  The removal of the NPB started on June 16, the complete removal was finished June 18.

Dissolved oxygen concentrations in the Stockton Deep Water Ship Canal have been above the 6.0 mg/l objective, and the Department of Fish and Game notified DWR that they will not be requesting a fall HOR barrier this year.   


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 were untied on June 16 and the barrier is now fully operating. The elevation of the MR weir was raised by one foot on  9/1/2010.

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. All flap-gates were untied on June 16 and the barrier is now fully operating.  ORT barrier culvert flap gates have been closed to tidal operation since 8/26/2010.  In order to help evaluate the effectiveness of improving water quality with the increased weir height at Middle River, the four center culvert at the ORT barrier will be tied up from 10/1/2010 to 10/7/2010.  Notification that this change was made was not received prior to sending this message.

Installation of the GLC barrier began on June 16 and the boat ramp was completed on July 2nd.  Barrier closure was completed on July 7.  The barrier is now fully operating.  Removal of the GLC barrier is going to start on 10/11/2010 in order to allow additional time to remove culverts that need to be replaced.

On September 15, 2010 the weir at MR and ORT was notched and the flash boards removed at GLC to allow salmon passage.


Water Levels/Water Quality Problem Notifications:




Modeling results are attached. Water levels for all stations are above the target levels.   The forecasted and actual stages have diverged with the actual stages approx. 0.5 feet lower than what the model is predicting.  We have double checked the model  and searched for potential causes.  One factor that we are looking into are the notches.  Normally the notches release such an insignificant flow that they are not modeled.  Now that the Middle River raise has raised water levels the notches are now deeper relative to the water levels and release more flow.  It is unlikely that the modeled and observed departure, especially in Old River and Grantline Canal is only a result of the notches, and we will continue to look for other potential factors.

The opening of the ORT culverts today and closure on Thursday October 7, is to test the response of EC concentrations in the south Delta due to the Middle River raise.  EC concentrations in the San Joaquin River are now significantly higher than the EC in Middle River downstream of the barrier.  The ORT operation will test to see if we get a response before we start removing the barriers for the season. 


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!

Jacob McQuirk, 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) 653-9883  FAX: (916) 653-6077
Cell: (916) 425-6857 E-Mail: