Key Highlights

2007 Adult Migration Monitoring

San Joaquin River Conditions

South Delta Temporary Barriers

Delta Exports

Key Highlights:

2007 Adult Migration Monitoring. Stanislaus River fall-run Chinook salmon escapement has annually decreased over the past four year period (2003-2006) and this trend appears to be continuing in 2007. Since annual weir monitoring at RM 31.4 was initiated in 2003, adult passage by this time of year has ranged from 467 to 2,111 Chinook. In comparison, this year only 76 Chinook have been observed passing the weir as of October 21, 2007.

San Joaquin River Conditions. San Joaquin River flow at Vernalis increased during the second half of the month as a result of increased releases from the tributaries, principally the fall attraction pulse flow from the Stanislaus River. Water temperatures continued a steady decrease as a result of cooling ambient air temperatures. Dissolved oxygen in the deep water ship channel (measured at Rough 'n Ready Island) increased to 7.8 mg/L by the middle of the month, but then dipped slightly to 6.8 mg/L for several days as flow increased at Vernalis.

South Delta Temporary Barriers. The Head of Old River Barrier (HORB) was installed on October 18 to increase flows and dissolved oxygen in the lower San Joaquin River for the benefit of Chinook salmon migration.

Delta Exports. Combined exports at the state and federal pumps averaged approximately 7,700 cfs during October, a decrease of almost 2,000 cfs over the month of September, which is typical in years with below average precipitation.

We encourage subscribers to contribute any relevant information for future issues of the newsletter (e.g., additional monitoring studies, announcements of upcoming meetings and events, etc). If you would like to contribute, please contact Chrissy Sonke. If you have any questions please contact Doug Demko at 530-342-9262 or by e-mail at dougdemko@fishbio.com.

To view a print version of this newsletter, click here.

Upcoming Events

Nov. 14: VAMP Technical Team Meeting
Dec. 12: CALFED Ops Meeting
Jan. 17: SRFG Meeting

Featured Links

CALFED Ops
Temporary Barrier Operating Schedule
South Yuba River Citizen League

Related Links

Tuolumne River Technical Advisory Committee
Calaveras River Fish Group
Stanislaus River Fish Group
San Joaquin River Group Authority
San Joaquin River Management Program

2007 Adult Migration Monitoring

Between October 1 and October 21, a net total of 53 Chinook were recorded as they passed upstream of the weir, increasing the season total to 76 Chinook. Daily upstream passage ranged from zero to eight Chinook. Weir passage included two adipose fin clipped (ad-clipped) Chinook observed: one on October 10 and one on October 13.

Two trapping events occurred during the sampling period (October 12-13 and October 17-18). A total of seven Chinook were trapped. Forklength ranged from 550 mm to 1,030 mm (avg: 814 mm) and consisted of five male and two female Chinook.

A spawned out, male, ad-clipped Chinook was recovered on top of the weir on October 18. CDFG subsequently read the coded-wire tag (CWT) retreived from the head of the carcass and determined it was a Feather River spring-run fish from brood year 2003 (tag code 06-24-02).

Releases from Goodwin Dam (GDW) were increased from 200 cfs to 800 cfs between October 16 and October 21 as part of the annual fall attraction flow. Flows will remain elevated until October 31 at which time they will be decreased to 300 cfs. Fall attraction flows are intended to facilitate the upstream migration of adult Stanislaus River fall-run Chinook through the San Joaquin River mainstem and into the Stanislaus River. The duration and magnitude of the attraction flows vary depending on the amount of water available for fishery flows, but typically range from 700 to 1,100 cfs for 7 to 12 days. So far, overall passage at the weir to date is significantly lower than any other year the weir has been operated. In previous years, passage as of October 21 ranged from 467 (2006) to 2,111 (2003) Chinook.

Releases from Goodwin Dam (GDW; RM 58.4) ranged between 186 cfs and 788 cfs; flow at Orange Blossom Bridge (OBB; RM 46.9) ranged between 228 cfs and 524 cfs; and flow at Ripon (RIP; RM 15) ranged between 250 cfs and 604 cfs. Turbidity at the weir site ranged from 0.52 NTU to 2.51 NTU and DO averaged 9.9 mg/L. DO downstream of the weir at Ripon (RM 15) ranged from 7.6 mg/L to 9.2 mg/L (avg: 8.4 mg/L). Daily instantaneous water temperature at the Stanislaus River weir ranged from 55.0 ºF to 60.2 ºF.

San Joaquin River Conditions

Flow in the San Joaquin River at Vernalis fluctuated between 1,073 cfs and 1,249 cfs during the first half of October, then increased the remainder of the reporting period to approximately 1,700 cfs as a result of the abovementioned Stanislaus River fall attraction flow, irrigation operations, and slight increases in tributary releases from the Tuolumne (~50 cfs increase) and Merced (~25 cfs increase) rivers. Water temperatures in the San Joaquin River continued a steady decline that began in early September as a result of cooling ambient air temperatures. Water temperature in the San Joaquin ranged from 60.0 °F to 66.7 °F (avg: 63.9 °F) at Vernalis; from 61.4 °F to 67.3 °F (avg: 64.5°F) at Mossdale; and from 62.8 °F to 69.6 °F (avg: 66.5 °F) at Rough 'n Ready Island. Dissolved oxygen (DO) in the San Joaquin River at Mossdale fluctuated between 8.8 mg/L and 10.6 mg/L (avg: 9.6 mg/L). DO in the deep water ship channel (measured at Rough 'n Ready Island) continued to steadily increase reaching 7.8 mg/l by October 12. Coincident with increasing flows at Vernalis due to increases from the Tuolumne and Merced rivers and irrigation operations, DO levels began to decline on October 13, reaching approximately 6.8 mg/L by October 17-18. Dissolved oxygen then quickly increased to 9.3 mg/L by October 21 following installation of the Head of Old River barrier and coincident with increasing river flows at Vernalis from the Stanislaus River fall attraction flow.

South Delta Temporary Barriers

Four rock barriers are constructed annually in the South Delta as part of the South Delta Temporary Barriers Program (Program). The objective of the Program is 1) increase water levels, circulation patterns, and water quality in the South Delta for for local agricultural diversions; and 2) to improve operational flexibility of the State Water Project to reduce fishery impacts and improve fishery conditions. The Head of Old River Barrier (HORB) is installed in the spring during VAMP and in the fall during the adult salmon migration season for fishery protection purposes and is at the discretion of California Department of Fish and Game (CDFG).

On September 27, the California Department of Fish and Game (CDFG) requested that the Head of Old River Barrier (HORB) be installed in October. Construction of the HORB began on October 8 and the closure was completed on October 18. The HORB’s purpose is to prevent San Joaquin flows from entering the Old River resulting in an increase in San Joaquin River flows past Stockton and an associated increase in dissolved oxygen levels in the Deep Water Ship Channel for the benefit of migrating adult salmon. Last year, there was no need to install the barrier because of adequate dissolved oxygen levels and high flows.

Delta Exports

Mean daily pumping at the C.W. Jones Pumping Plant (federal pumps previously known as Tracy Pumping Plant) remained fairly constant during the reporting period, averaging 4,261 cfs. Mean daily pumping at the Harvey O. Banks Pumping Plant (state pumps) decreased by almost 2,000 cfs as compared to the month of September, and has been varying from 2,474 cfs to 5,115 cfs, averaging approximately 3,408 cfs.

To view newsletter archives, click here.

© 2007 FISHBIO Environmental, LLC
3188 Wood Creek Drive, Chico, CA 94928

Data Disclaimer:  The data displayed on the sanjoaquinbasin.com website are courtesy of California Department of Fish & Game (CDFG), U.S. Fish & Wildlife Service (USFWS), Tri-dam, Turlock Irrigation District (TID), Modesto Irrigation District (MID) and FISHBIO.  Data are intended to be current, but are preliminary and are not guaranteed to be accurate.  Source data compiled and provided by FISHBIO, from whom further information can be obtained.  Use or reproduction of this data is prohibited without prior permission of CDFG, USFWS, Tri-dam, TID, MID and/or FISHBIO.