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 6, 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 September 26, the Middle River gage was reporting suspicious data, it was later discovered that the station was vandalized. The repairs of the station was completed on October 3.
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 barrier is functioning as designed, and the boat tender is on duty.
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 the barrier was closed on June 8, 2016. All flap gates resumed tidal operation as of June 17, 2016. The barrier is functioning as designed, and the boat tender is also on duty.
Notching of the MR and ORT barriers for salmonid passage 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 environmental permits. 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 was achieved on September 27th, 2016 at 1100 hours. Construction was completed on September 29th.
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 been 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 construction of the Fall HORB. However, thick algal bloom was observed near the vicinities of the barrier sites and toxic algae has been verified. DWR will continue to monitor the water quality parameters and the water levels.
Caution: A harmful algal bloom is present in the South Delta and the County Health Department has posted warnings against contact at local marinas.
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 continued. Diversions from Tom Paine Slough had 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.
TBP staff met with representatives from Woods Irrigation Company that diverts from Middle River near Howard Road and South Delta Water Agency on 9/26 to discuss chronic water level issues Woods IC has experienced this season and what can be done to improve the situation. Work will be done after the barrier is removed to assure that the barrier is functioning as designed during the 2017 irrigation season. Culvert repairs may be necessary.
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 09-28-16 through 10-24-16. For the modeling duration, the water levels at 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. The reported water level data at Middle River indicated that it was below the 2.5 feet concern level; further investigation determined that the station was vandalized. DWR crews fixed the station on October 3. 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 at Howard Road should not be trusted between September 26 to October 3.
Real-time south Delta water level data is available on CDEC at the URL below:
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Simon Kwan, P.E.
Temporary Barriers and Lower San Joaquin
1416 9th St., Room 215-29
Sacramento, CA 95814
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