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: October 3, 2016
Agricultural Barriers (Middle River [MR], Old River near Tracy [ORT], Grant Line Canal [GLC]):
The installation of the Middle River barrier started on March 2, 2016; closure was achieved by March 9, 2016. All flap gates are tidally operating as of April 1, 2016. DWR raised the weir crest by one additional foot on June 22, 2016 to aid south Delta farmers during the high demand irrigation season. On 8/11/16 divers inspected the barrier and all flap gates are operating correctly. A very small void on two of the culverts was observed between the flap gates and the collar connecting to the corrugated metal pipe. The size of the leak is negligible and repairs are not warranted.
On 8/16/16 staff noticed the stage at gaging station “MHR” on Middle River looked suspiciously high. A crew visited the site and replaced the 2” galvanized conduit that houses the bubble line at MHR.
The installation of the Old River near Tracy barrier started on March 3, 2016; the construction crew closed the barrier on March 25, 2016. The flap gates were released to tidal operation on April 1, 2016. The boat tender is on duty. Water hyacinth was removed to make the portage facility functional again in the week of July 18, 2016. Last week dive team inspected the flap gates at the Old River near Tracy barrier; one severed wire rope was replaced and debris removed from a culvert. No other damage was observed.
The construction crew started working on the Grant Line Canal barrier on Monday March 28, 2016; the in-water work started on March 30, 2016 with partial closure attained by April 14, 2016. Mobilization to close the barrier started on May 25, 2016, the work started on May 26, 2016 and barrier was closed on June 8, 2016. All flap gates resumed tidal operation as of June 17, 2016. The boat tender is also on duty.
Notching of the MR and ORT barriers was conducted on September 12, 2016 and the top flashboard of the GLC flashboard structure was set at 2.5 feet.
Head of Old River Barrier [HORB]:
The construction of the Spring Head of Old River barrier started on March 10, 2016 with closure achieved by April 1, 2016. All slide gates were placed in the open position in accordance with the Biological Opinions. Mobilization for the removal of the barrier started on May 27, 2016; the breach was achieved on June 01, 2016, and the removal was completed on June 14, 2016.
On September 1, 2016 CDFW requested DWR install the Fall Head of Old River Barrier (FHORB). The FHORB construction started on Wednesday September 15, 2016 and channel closure is achieved on September 27, 2016.
Environmental Permits Compliance Reporting:
Environmental staff conducted pre-construction surveys as required by the State and Federal permits and by Biological Opinions. Environmental monitors have and will be presented for construction activities. No environmental issues have be observed.
Water Levels and Water Quality Notifications:
No exceedance were observed of the water quality turbidity measurements during the installation of the MR, ORT, GLC, and HORB installations and no exceedance was observed during the removal operation of the HORB. DWR will continue to monitor the water quality parameters and the water levels.
South Delta Water Agency has reported water level issues on Tom Paine Slough impacting Pescadero Reclamation District as well as Middle River impacting Woods Irrigation Company. Problems were first reported on 07-12-2016 and continue. Diversions from Tom Paine Slough have been significantly reduced, and assistance has been requested. DWR had the Middle River barrier weir elevation checked on September 3, 2016. Survey results showed the weir elevation was in compliance.
Thanks to Reza of the Delta Compliance and Modeling Section, computer modeling was performed and a copy of the modeling results is attached for the modeling duration from 09-21-16 through 10-17-16. For the modeling duration, the water levels at the Middle River barrier, the Old River near Tracy barrier, and the Grant Line Canal barrier near Doughty Cut were above the concern level of 2.5 feet National American Vertical Datum. Field data collected by the monitoring stations revealed a close match to modeled results for both the Old River near Tracy and the Grant Line Canal barriers, but monitoring station data for the Middle River site revealed higher water level values than the ones the model showed.
Real-time south Delta water level data is available on CDEC at the URL below:
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Jacob McQuirk, P.E.
Temporary Barriers and Lower San Joaquin
1416 9th St., Room 215-23
Sacramento, CA 95814
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