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 9, 2008

Welcome to the beginning of the 2008 Temporary Barriers Project season!

Head of Old River Barrier (HORB):

The spring HOR barrier work will not be installed this year due to a court decision by US District Court Judge Wanger that prohibited the installation of the spring barrier to increase protections for delta smelt.  This is an interim decision that effects the 2008 season only.  The fall HORB is not effected.

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

Ag barrier work will begin May 12 at the DMC barrier.  The GLC and MR barrier will begin work about a week later.  The DMC barrier will close about the end of May and the MR barrier will close about May 20.  The GLC barrier will only have the boat ramp installed, leaving the middle portion open, however modeling will be done to determine if full closure of the GLC barrier is necessary after late May to protect water levels.  Exact dates of starting and closure will be provided as the schedule develops in upcoming updates.  All flap gates on the barriers will be tied open until after the Vernalis Adaptive Management Plan experiment is concluded in accordance with the Wanger decision.



Modeling will begin during the barrier construction with the forecast of water levels looking at the week of May 19 and the following week.  This will give us an indication of whether water levels will be adequate and whether the GLC barrier needs to be closed late in May or early June. 


Fishery agencies and DWR will be closely monitoring conditions for Delta smelt which might effect operations of the barriers during May/June.  Changes in flap-gate operations on the culverts, delaying filling of the GLC center section, 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 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/Pager: (916) 601-6036 E-Mail: