| Volume 2008/09, Issue 2 |
November 5, 2008 | |
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Key Highlights
2008 Stanislaus River Weir Monitoring. A total of 482 Chinook were recorded at the Stanislaus River weir between October 2 and October 30, increasing the season total to 598. In comparison, total passage through October 30 in previous years ranged from a low of 208 Chinook in 2007 and a high of 2,472 Chinook in 2003.
Tributary Carcass Surveys. Weekly carcass surveys conducted by the California Department of Fish and Game began in the San Joaquin Basin tributaries during the first week in October.
San Joaquin River Conditions. Flows in the San Joaquin River at Vernalis ranged between 653 cfs and 1,325 cfs with flows peaking between October 12 and October 15 associated with the Stanislaus River fall-run Chinook attraction pulse flow.
Delta Exports. Combined total exports (state and federal pumping plants) fluctuated between 3,795 cfs and 4,840 cfs. 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.
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2008 Stanislaus River Weir Monitoring
Between October 2 and October 30, a total of 482 Chinook were recorded passing upstream of the weir, increasing the season total to 598. In comparison, total passage through October 30 in previous years ranged from a low of 208 Chinook in 2007 and a high of 2,472 Chinook in 2003 (Figure 1). During this sampling period, daily upstream passage ranged between one and 46 Chinook. Weir passage included 23 Chinook with clipped adipose fins (ad-clipped), increasing the season total ad-clipped fish to 24 (4.0% of passage to date).
Figure 1. Cumulative Chinook salmon upstream passage recorded at the Stanislaus River Weir, 2003 to 2008.
Two trapping events were conducted during the sampling period (October 23-25 and October 27-29). A total of 11 Chinook were trapped consisting of seven males and two females (Figure 2). Total lengths ranged from 725 mm to 1090 mm (avg: 914 mm).
Figure 2. Chinook salmon male (left) and female (right). Note: adipose fin absent in male.
The annual fall attraction pulse flow was conducted between October 8 and 23 with Goodwin Dam (GDW; RM 58.4) releases ramping up from about 200 cfs to 850 cfs by October 10, remaining at 850 cfs through October 13, and then ramping down beginning on October 14 to 250 cfs by October 24 (Figure 3). 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.
Releases from Goodwin Dam (GDW; RM 58.4) ranged between 202 cfs and 856 cfs and flow at Ripon (RIP; RM 15) ranged between 221 cfs and 665 cfs (Figure 3). Instantaneous water temperatures at the weir ranged between 53.0˚F and 64.7˚F, while daily average water temperatures at Ripon (RPN; RM 15) ranged between 54.9˚F and 69.4˚F (Figure 4). Instantaneous turbidity at the weir site ranged between 0.3 NTU and 2.5 NTU (Figure 5). Instantaneous dissolved oxygen at the weir ranged between 7.8 mg/L and 10.7 mg/L, while daily average dissolved oxygen at Ripon (RPN; RM 15) ranged between 8.1 mg/L and 10.0 mg/L (Figure 6).
Figure 3. Daily upstream Chinook passage recorded at the Stanislaus River Weir in relation to daily average flows (cfs) recorded in the Stanislaus River at Goodwin (GDW) and Ripon (RIP) and in the San Joaquin River at Vernalis (VNS), 2008. Note: flows downstream of Goodwin Dam may be higher than dam releases due to irrigation returns.
Figure 4. Daily upstream Chinook passage recorded at the Stanislaus River Weir in relation to instantaneous water temperature recorded at the weir and daily average water temperature recorded in the Stanislaus River at Ripon (RPN) and in the San Joaquin River at Vernalis (VER), Mossdale (MSD) and Rough & Ready (RRI), 2008.
Figure 5. Daily upstream Chinook passage recorded at the Stanislaus River Weir in relation to instantaneous turbidity recorded at the weir, 2008.
Figure 6. Daily upstream Chinook passage recorded at the Stanislaus River Weir in relation to instantaneous dissolved oxygen recorded at the weir and daily average dissolved oxygen recorded in the Stanislaus River at Ripon (RPN) and in the San Joaquin River at Mossdale (MSD) and Rough & Ready (RRI), 2008.
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Tributary Carcass Surveys
The California Department of Fish and Game began their annual adult fall-run Chinook carcass surveys during the first week of October on the Merced, Tuolumne, and Stanislaus Rivers. As of October 26, three weekly surveys have been completed with the most significant activity observed during week three (i.e., week of October 20). Although numbers are extremely low on all tributaries, the largest number of live fish was observed on the Stanislaus River with a peak live count thus far of 49 Chinook. Peak live counts on the Tuolumne and Merced Rivers were 22 and six, respectively.
The highest number of redds was observed on the Stanislaus River with a peak redd count thus far of 60. Peak redd counts on the Tuolumne and Merced Rivers were six and zero, respectively. Typically, a peak in the number of redds observed occurs in mid to late November.
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San Joaquin River Conditions
During the reporting period, flows in the San Joaquin River at Vernalis ranged between 653 cfs and 1,325 cfs with flows peaking between October 12 and October 15 associated with the Stanislaus River fall-run Chinook attraction pulse flow (Figure 7). Average daily water temperatures in the San Joaquin River ranged between 55.7°F and 72.3°F at Vernalis, between 56.3°F and 72.7°F at Mossdale; and between 62.8°F and 73.8°F at Rough 'n Ready Island. Average daily dissolved oxygen (DO) in the San Joaquin River ranged between 5.3 mg/L and 9.9 mg/L in the deep water ship channel (measured at Rough 'n Ready Island) and between 8.2 mg/L and 10.4 mg/L at Mossdale (Figure 9).
 Figure 7. San Joaquin River flow at Vernalis, water year 2008.
 Figure 8. San Joaquin River daily average water temperature at Vernalis, Mossdale, and Rough 'n Ready, water year 2008.
Figure 9. San Joaquin daily average dissolved oxygen at Mossdale and Rough 'n Ready, water year 2008.
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Delta Exports
Mean daily pumping at the C.W. Jones Pumping Plant (federal pumps previously known as Tracy Pumping Plant) fluctuated between 3,244 cfs and 4,486 cfs (Figure 10). Mean daily pumping at the Harvey O. Banks Pumping Plant (state pumps) fluctuated between 379 cfs and 820 cfs. Combined total exports (state and federal pumps) fluctuated between 3,795 cfs and 4,840 cfs.
Figure 10. Daily exports at the Federal and State pumping stations, water year 2008.
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