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:  August 15 , 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]):

All the agricultural barriers are operating normally, with their culvert flap gates opening and closing tidally.  However, on Thursday morning, three more culverts were tied open on the ORT barrier for water quality purposes for a total of six tied open.  These additional open culverts will help improve circulation particularly while a spring tide is occurring and without adversely impacting water levels.  Generally, this will be our normal operation (more open culverts during the spring tides, less open culverts on the neap tides) as we move from spring to neap tides as long as they don’t adversely cause water levels to drop below trigger levels.  Normally, we’ll make the changes about a week apart and we’ll be looking at water quality data to see if we can see an improvement in quality upstream of the barrier on Old River.


Modeling results are attached with forecasts though 8/22/08. Modeling shows that actuals and forecasts are good for water levels with three culverts tied open at the ORT barrier.  However, modeling wasn’t done in time to reflect the three additional culverts tied open on Thursday.  We expect low-low water levels upstream of the ORT barrier to be slightly lower than shown in the plots but not enough to warrant culvert changes.  Water levels have been well above the trigger levels (0.0 feet MSL at both ORT and GLC barriers, 0.3 feet MSL at the MR barrier) and should remain above these levels through next week.

Click here to see modeling outputs


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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: