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: May 24, 2013
Head of Old River (HOR) Barrier:
Spring Head of Old River barrier will not be constructed in 2013.
Agricultural Barriers (Middle River [MR], Old River near Tracy [ORT], Grant Line Canal [GLC]):
DWR received the Section 404 CWA/Section 10 RHA permit for 2013-2017 on Tuesday May 7, and construction of the south Delta temporary rock barriers started on Wednesday May 8. Construction of the Middle River barrier and Old River near Tracy barrier both started on May 8, and closure of the Middle River barrier was obtained on May 14 at approximately 2 PM. All flap gates at MR remain tied open and construction is complete at this site. The Old River near Tracy barrier is currently scheduled to be completed before May 29 and the Grant Line barrier completed in mid June.
Environmental Permits Compliance Reporting:
Environmental Compliance monitoring has been occurring as scheduled.
Middle River--Construction is complete at this site. A nesting pair of Swainson’s hawks have been observed on an island west of the Middle River Barrier and appear to be incubating eggs as of May 18th. Nesting Barn Swallows were observed in one of the flap gate control boxes and was monitored until the young fledged on May 18th. Once the young had fledged the nest was removed and the control box was covered to exclude the swallows. No western pond turtles were observed during construction.
Old River Tracy--A pair of nesting great horned owls was observed with young before construction on the South side of Old River, East of the barrier site, however, when construction began the nest was empty and appeared to have failed. A nesting pair of red-tailed hawks is located on the South side of Old River across from the storage and staging area. As of May 18th, two young are in the nest and appear to be healthy and unaffected by construction activities. Acoustical monitoring occurred at the construction site on Monday, May 20th and sound levels were all below the threshold set forth in the NMFS Biological Opinion. No western pond turtles have been observed in the construction area.
Grant Line Canal--At Grant Line Canal three pairs of nesting Swainson’s Hawks have been observed near the barrier construction site. All three pairs have been observed incubating eggs as of May 18th and observations of these nests suggest that construction activities are not causing significant disturbances to the nesting pairs. No western pond turtles have been observed in the construction area. Acoustical monitoring is scheduled to begin this week at the construction site.
Water Quality Monitoring:
Turbidity data was collected during the construction of the Middle River and the Old River at Tracy barriers. Data revealed no violation of the water quality guidelines. The processed data was mailed to the CVRWQCB as per the 401 permit requirement. The data collecting and reporting will continue for the duration of construction period.
Water Levels and Water Quality Notifications:
It is discovered that flap-gates at Tom Paine Slough siphons are in need of replacement. Divers removed the damaged flap gates on May 16 and 17, 2013. Due to a problem with the flap gate supplier, installation is now scheduled to start on May 28, 2013. In order to protect water level in Tom Paine Slough, Pescadero Irrigation District siphons are being stopped and started with tides until the repair is complete.
Middle River barrier was closed on May 14th, Old River near Tracy barrier to be closed on May 31st, and Grantline Canal barrier to be partially closed on June 7th, 2013. All flap-gates on the Middle River and Old River near Tracy barriers will be released to tidal operation on June 1st, 2013, Grantline Canal barrier flap-gates to stay tied open until Delta Smelt concerns have passed.
Modeling results are attached and forecasted minimum water levels will drop below target levels at all three monitoring locations.
Water levels for the forecast period are as follows:
Middle River at Howard Road (sta MHR) – Actual low water levels are approximately 1.0 ft above the modeled forecast. Modeling shows low water levels will drop to approximately -0.4 ft (0.7 ft below the target of 0.3 ft) on May 31, 2013, then rebound to approximately 0.5 ft on June 6th, the end of the forecast period.
Old River at Tracy Blvd. (sta OLD)– Actual low water levels are approximating the modeled forecast. Modeling shows low water levels will drop to approximately -0.7 ft (0.7 ft below the target of 0.0 ft) on May 30, 2013, then rebound to approximately 0.5ft on June 6th, the end of the forecast period.Doughty Cut (sta DGL) – Actual low water levels are approximating the modeled forecast. Modeling shows low water levels will drop to approximately -0.6 ft (0.6 ft below the target of 0.0 ft) on May 30, 2013, then rebound to approximately -0.2 ft on June 6th, the end of the forecast period.
Real-time south Delta water level data is available on CDEC at the URL below:
These weekly updates are also available for your information on our website:
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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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