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 30 , 2008


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]):

Work began May 12 at the DMC barrier.  While we were expecting to close this barrier today, instead it will close on Monday, June 2.  The Middle River barrier construction began on May 20 and was completed May 21.  Crews began construction of the Grant Line Canal north abutment (boat ramp) on May 19.  Partial closure (completion of the boat ramp) is now expected June 2 as well (was June 4 last week).  Full closure of the GLC barrier will be determined afterwards depending on water levels and delta smelt issues.  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.  After VAMP, the flap gates may be untied (operating normally) if necessary to protect south Delta water levels but only with fishery agencies approval.  Currently fishery requirements dictate that the gates will remain tied open until at least June 3.



We included actual water levels through yesterday morning.  Note that the modeling done last week was based upon closing the ORT barrier on May 30, however, due to equipment breakdown on Friday, the closing won’t actually occur until today, June 4.  The forecast plots do not reflect that fact.  Modeling being done this week will include the new closure date.  

Click here to see modeling outputs


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: