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 18 , 2007

Head of Old River Barrier (HORB):

In response to fishery agency concerns over the distribution and abundance of Delta smelt, the Water Operations Management Team (WOMT) (comprised of SWP/CVP and fishery agencies management) decided this week to open the remaining three culverts immediately at the Head of Old River followed by removing the barrier completely.  The culverts were opened on May 16 and notice was given to the barrier contractor to begin the removal process.  The barrier is expected to be breached on May 21.


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

Barrier installations began April 2, 2007. The ORT and MR barriers are closed and culverts operating tidally.  The GLC barrier closed on Thursday, May 10



Modeling was not done this week as the HOR barrier is being removed and therefore modeling to determine operations of the HOR barrier culverts is not needed. 


Fishery agencies and DWR will be closely monitoring conditions for Delta smelt which might effect operations of the barriers during April-May.  Changes in flap-gate operations on the culverts, removal of the barriers, and changes to SWP/CVP export operations are all possible actions that could be taken to protect smelt if necessary.  


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

Please delete your old “favorite” for the Temporary Barriers Project and add this new site!

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/Pager: (916) 601-6036 E-Mail: