Volume 2010/11, Issue 3
| October 19, 2010 |
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VAMP Biology Technical Team Meeting:
Oct. 21
Stanislaus River Salmon Festival:
Nov. 14
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Photo by FISHBIO.
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Key Highlights
Stanislaus River Weir Monitoring continued during the reporting period, and 218 Chinook salmon have been counted as of October 10.
Tuolumne River Weir Monitoring continued during the reporting period, and 163 Chinook salmon have been counted as of October 10.
Merced River. As of October 4, no Chinook salmon have been spawned at the Merced River Fish Facility.
San Joaquin Basin Escapement Surveys. Annual carcass surveys conducted by CDFG began on the Stanislaus River during the week of September 27 and in Merced and Tuolumne Rivers during the week of October 4.
Mokelumne River Woodbridge Dam Fish Ladder Monitoring. As of October 10 a total of 818 Chinook passed upstream of the dam.
San Joaquin River Conditions. San Joaquin River flows at Vernalis ranged between 1,523 cfs and 2,200 cfs. Water temperatures in the San Joaquin River ranged between 65.5�F and 73.3�F. Average daily dissolved oxygen (DO) in the San Joaquin River fluctuated between 6.1 mg/L and 9.5 mg/L at Mossdale, and between 5.8 mg/L and 6.6 mg/L at Rough 'n Ready.
Delta Exports.Combined total exports (state and federal pumps) fluctuated during the reporting period and ranged from 8,992 cfs to 10,869 cfs.
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2010/11 Stanislaus River Weir Monitoring
 | | Figure 1. Stanislaus River weir. |
Between September 23 and October 10 a total of 152 fall-run Chinook salmon were detected by the Vaki Riverwatcher as they passed upstream of the Stanislaus River weir, increasing the season total to 218 (Figures 1 and 2). Daily passage ranged between 1 and 28 Chinook (Figure 4). The number of Chinook passages observed so far this year is similar to
passages observed during this period in most other years (Table 1; Figure 3).
Instantaneous water temperature measured at the weir ranged between 61.3˚F and 66.5˚F and daily average water temperature at Ripon
 | | Figure 2. Chinook passage through the Vaki Riverwatcher at the Stanislaus River weir. |
(RPN; RM 15) ranged between 64.4˚F and 71.2˚F (Figure 5). Instantaneous turbidity ranged between 0.15 NTU and 2.08 NTU (Figure 6). Instantaneous dissolved oxygen ranged between 8.12 mg/L and 9.96 mg/L and daily average dissolved oxygen at Ripon (RPN; RM 15) ranged from 8.48 mg/L to 9.42 mg/L (Figure 7).
Daily average flows in the Stanislaus River at Goodwin Dam (GDW; RM 58) remained stable between 200 cfs and 208 cfs. Flows at Ripon (RIP; RM 15) fluctuated between 220 cfs and 258 cfs (Figure 4). Note: flows downstream of Goodwin Dam may fluctuate from dam releases due to irrigation, precipitation and other factors.
Table 1. Annual Fall-run Chinook passage prior to October 10, 2003-2010.
  Figure 3. Fall-run Chinook salmon cumulative passage recorded at the Stanislaus River weir from 2003-2010.
Figure 4. Daily upstream Chinook passage 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) in 2010.
Figure 5. 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) in 2010.
Figure 6. Daily upstream Chinook passage at the Stanislaus River weir in relation to instantaneous turbidity recorded at the weir in 2010.
 Figure 7. Daily upstream Chinook passage 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) in 2010.
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2010/11 Tuolumne River Weir Monitoring
 | | Figure 8. Tuolumne River weir fish passage. Click photo to read more about the 2010 weir modifications on our Field Notes. |
Between September 23 and October 10 a total of 144 Chinook salmon were detected by the Vaki Riverwatcher as they passed upstream of the Tuolumne River weir, increasing the season total to 163 (Figures 8 and 9). Daily passage ranged between 3 and 26 Chinook (Figure 11). The number of Chinook passages observed so far this year is much greater than the number observed during the same period in 2009 (Table 2; Figure 10).
Instantaneous water temperature measured at the weir ranged between 58.5˚F and 70.1˚F. Daily average water temperature at Modesto (MOD; RM 17) decreased from 69.8˚F to 59.3˚F (Figure 12). Instantaneous turbidity  | | Figure 9. Chinook passing through the Vaki Riverwatcher at the Tuolumne River weir. Click photo to view video clip of Chinook passing through the Vaki Riverwatcher. |
ranged between 0.44 NTU and 3.48 NTU (Figure 13), and instantaneous dissolved oxygen ranged between 8.05 mg/L and 9.45 mg/L (Figure 14). Daily average flows in the Tuolumne River increased from 304 cfs to 860 cfs at La Grange (LGN; RM 50) and from 418 cfs to 941 cfs at Modesto (MOD; RM 17) (Figure 11). Note: flows downstream of La Grange may be higher than dam releases due to accretion and Dry Creek inflow.
Table 2. Annual Fall-run Chinook passage prior to October 10, 2009 and 2010.  
Figure 10. Fall-Run Chinook salmon cumulative passage recorded at the Tuolumne River weir in 2009 and 2010.
 Figure 11. Daily upstream Chinook passage at the Tuolumne River weir in relation to daily average flows (cfs) recorded in the Tuolumne River at La Grange (LGN) and Modesto (MOD), and in the San Joaquin River at Vernalis (VNS) in 2010.
Figure 12. Daily upstream Chinook passage at the Tuolumne River weir in relation to instantaneous water temperature recorded at the weir, and daily average water temperature recorded in the Tuolumne River at Modesto (MOD), and in the San Joaquin River at Vernalis (VER), Mossdale (MSD) and Rough & Ready (RRI) in 2010.
Figure 13. Daily upstream Chinook passage at the Tuolumne River weir in relation to instantaneous turbidity recorded at the weir in 2010.
Figure 14. Daily upstream Chinook passage at the Tuolumne River weir in relation to instantaneous dissolved oxygen recorded at the weir, and daily average dissolved oxygen recorded in the San Joaquin River at Mossdale (MSD) and Rough & Ready (RRI) in 2010. |
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Merced River
 | | Figure 15. Gravel augmentation project on the Merced River. Click photo for more info from our Field Notes. |
As of October 4 no Chinook salmon have been spawned at the Merced River Fish Facility, and one live adult Chinook salmon has been observed during CDFG escapement surveys. As we get closer to November, the peak fall-run Chinook spawning time, more salmon will move up river to spawn in areas such as this site below Crocker-Huffman Diversion Dam with recent gravel augmentation (Figure 15). This augmentation project took place in late-August and was designed to enhance spawning habitat on the Merced River.
During the reporting period flows in the Merced River at Cressy (CRS; RM 52) fluctuated from 148 cfs to 189 cfs, and at Stevinson (MST; RM 5) from 320 cfs to 407 cfs (Figure 16). Water temperatures in the Merced River fluctuated between 65.6�F and 72.9�F at Cressy and between 65.3�F and 79.4�F at Stevinson (Figure 17).
Figure 16. Daily average flows (cfs) recorded in the Merced River at Cressy (CRS) and Stevinson (MST), 2010.
Figure 17. Daily average water temperature (�F) recorded in the Merced River at Cressy (CRS) and Stevinson (MST), 2010.
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San Joaquin Basin Escapement Surveys
Annual carcass surveys conducted by CDFG began on the Stanislaus River during the week of September 27 and on the Tuolumne and Merced tributaries during the week of October 4. The largest number of live fish was observed on the Tuolumne River, with a live count thus far of sixteen Chinook. Live counts on the Stanislaus and Merced rivers were two and one, respectively. Peak live count for fall-run Chinook salmon usually occurs during the month of November.
Four redds were observed on both the Stanislaus and Tuolumne rivers and no redds have been recorded on the Merced River. Typically, a peak in the number of redds observed for the fall-run season occurs in mid- to late-November.
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Mokelumne River Woodbridge Dam Fish Ladder Monitoring
Fall-run Chinook salmon returning to the Mokelumne are counted annually by East Bay Municipal Utility District (EBMUD) as they ascend the fish ladder at Woodbridge Dam. Escapement to the Mokelumne River has declined drastically in recent years from a high of 16,000 in 2005 to just a few hundred in 2008. In 2009, a total of 1,591 Chinook salmon were detected. As of October 10, a total of 818 Chinook passed upstream of the dam (Figure 18).
 Figure 18. Daily upstream Chinook passage recorded at the Woodbridge Dam fish ladder in relation to daily average flows (cfs) recorded in the Mokelumne River at Camanche Reservoir (CMN), 2010. Note: Graph does not include fish observed before September 22.
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San Joaquin Conditions
During the reporting period, flows in the San Joaquin River at Vernalis increased from 1,523 cfs to 2,200 cfs (Figure 19). Water temperatures in the San Joaquin River decreased from 73.3�F to 65.5�F at Vernalis, from 74.2�F to 66.9�F at Mossdale, and from 74.3�F to 71.1�F at Rough 'n Ready Island (Figure 20). Average daily dissolved oxygen (DO) in the San Joaquin River fluctuated from 5.8 mg/L to 6.6 mg/L in the deep water ship channel (measured at Rough 'n Ready Island) and between 6.1 mg/L and 9.5 mg/L at Mossdale (Figure 21).
Figure 19. San Joaquin River flows at Vernalis from October 1, 2009 through October 10, 2010.
Figure 20. San Joaquin River daily average water temperatures at Vernalis, Mossdale, and Rough 'n Ready from October 1, 2009 through October 10, 2010.
Figure 21. San Joaquin daily average dissolved oxygen at Mossdale and Rough 'n Ready, from October 1, 2009 through October 10, 2010.
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Delta Exports
Mean daily pumping at the C.W. Jones Pumping Plant (federal pumps previously known as Tracy Pumping Plant) remained relatively stable during the reporting period and fluctuated between 4,050 cfs and 4,161 cfs (Figure 22). Mean daily pumping at the Harvey O. Banks Pumping Plant (state pumps) ranged between 4,890 cfs and 6,732 cfs. Combined total exports (state and federal pumps) during this period ranged from 8,992 cfs to 10,869 cfs.
Figure 22. Daily exports at the Federal and State pumping stations from October 1, 2009 through October 10, 2010.
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