Delta Rock Barriers Updates

[WB Staff]

Below is a tentative removal schedule as of 20251030:

Barrier Start in-water work Breaching End in-water work
Old River near Tracy 10/27/25 10/28/25 11/17/25
Grant Line Canal 11/3/25 11/4/25 11/20/25
Middle River 11/19/25 11/19/25 11/25/25

Old River near Tracy Barrier
Mobilization to the site occurred on October 27. The weir was breached on October 28 at 9:30 a.m. The removal is scheduled to be completed on November 17.

Grant Line Canal Barrier
Removal is scheduled to start on November 3. Boat portage is still available daily including holidays from 6am to 8pm until the weir is opened wide enough for boat passage.

Middle River Barrier
Removal is scheduled to start on November 19.

Environmental Compliance
As required by the environmental permits, environmental monitors are present during all phases of removal including the in-water work. Environmental education is provided to crew members prior to starting work and required discrete turbidity, temperature, and dissolved oxygen monitoring data is being collected during the in-water work phase of the construction.

Water Level Modeling
The attached model run results cover the period October 28 through November 17 and are based on the following assumptions:

1. CCFB Gates are operating to Priority 3 in October, and to Priority 2 starting November 1.

2. The Delta Cross Channel gates are open until October 29, and are closed starting October 30.

3. Suisun Marsh Salinity Control flashboards are in. All three gates are in open position starting September 12.

4. San Joaquin River flow at Vernalis is at 1705 cfs at the beginning of the forecast period and is estimated to decrease to 1100 cfs by the end of the forecast period.

5. San Joaquin River EC at Vernalis is at 343 umhos/cm at the beginning of the forecast period and is estimated to increase to 413 umhos/cm at the end of the forecast period.

6. Sacramento River flow at Freeport is at 11942 cfs at the beginning of the forecast period and is expected to decrease to 10250 cfs by the end of the forecast period.

7. CCFB inflow is at 0 cfs at the beginning of the forecast period and is expected to increase to 2000 cfs by the end of the forecast period.

8. Export at Jones Pumping Plant is at 3513 cfs at the beginning of the forecast period and is expected to decrease to 2700 cfs to the end the forecast period.

9. The Middle River barrier gates are in full tidal operation from July 31. The weir elevation was raised by 1 foot on August 12. The barrier will be breached on November 20.

10. The Old River near Tracy barrier gates are in full tidal operation. The barrier will be breached on October 28.

11. The Grant Line Canal barrier gates are in full tidal operation. The barrier will be breached on November 4.