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:  September 12, 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.  The fall HORB generally is installed late in September upon the request of the CA Department of Fish and Game and depends upon the current and projected dissolved oxygen levels in the San Joaquin River near Stockton.

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.  Six culverts are tied open on the ORT barrier for water quality purposes.  Generally, our normal operation is to have more open culverts during the spring tides, less open culverts on the neap tides, as we move from spring to neap tides.  We do this as long as they don’t adversely cause water levels to drop below trigger levels. This week water levels are very good and are expected to remain so, and as we enter a spring tide period, we are keeping more culverts open to help with water quality.  Typically 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.

In compliance with the TBP permit conditions, the agricultural barriers at Old River Tracy and Middle River were notched on 9/10/08.  The flashboards on the south side of the Grant Line Canal were removed which serves the same purpose as notching. The notches will allow a minimum depth of 6 inches of water to pass over the barrier during the lower high tide event.  This action helps ensure adult Chinook salmon that have strayed into the south Delta can pass over the barriers on their way to the San Joaquin River.


Modeling results are attached and include forecasts though 9/19/08. Modeling shows that actuals and forecasts are good for water levels with six culverts tied open at the ORT barrier.  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: