Chapter 4 Upper Sacramento Juveniles

This section describes environmental attributes associated with and responses during the out-migrating juvenile life stage in the Upper Sacramento River.

4.1 Habitat Attributes

4.2 Environmental Drivers

4.2.1 Flow

Figure 4.1: Daily Flows (cfs) at Sacramento River at Keswick (KWK) and Sacramento River at Bend Bridge (BND) in July through September 2021 and over the 10-year average

Table 4.1: Mean, Maximum, Minimum Monthly Flows (cfs) at Sacramento River at Keswick (KWK) and Sacramento River at Bend Bridge (BND) in July through December 2021
Year Month Station Mean Min Max
2021 July BND 9642.1 9030 10600
2021 August BND 8334.2 6840 9670
2021 September BND 7072.0 6840 7300
2021 October BND 13618.0 6220 36800
2021 November BND 8279.9 4260 17700
2021 December BND 10327.5 4220 26600
2021 July KWK 9510.2 8740 10800
2021 August KWK 8102.0 6610 9500
2021 September KWK 6899.8 5310 8500
2021 October KWK 6160.1 5120 7330
2021 November KWK 4027.1 3070 5080
2021 December KWK 3431.0 3040 3970
  • Keswick: Peak flows were 10800 cfs and occurred in July. The highest mean flows were 9510.2 cfs and occurred in July.
  • Bend Bridge: Peak flows were 36800 cfs and occurred in October. The highest mean flows were 13618 cfs and occurred in October.

4.2.2 Water Temperature

Figure 4.2: Daily Water Temperature (degF) at Sacramento River at Bend (BND) in 2021 and 10-year average between July and December.

Table 4.2: Mean, Maximum, Minimum Monthly Water Temperature (degF) at Sacramento River at Bend Bridge (BND) in July through December 2021
Year Month Station Mean Min Max
2021 July BND 59.3 55.9 62.6
2021 August BND 59.2 56.0 62.2
2021 September BND 60.9 58.7 63.0
2021 October BND 59.5 57.1 61.8
2021 November BND 54.0 45.2 60.6
2021 December BND 50.4 45.6 55.6

Summary

  • In 2021 water temperature was below average for most of the season between July and December.
  • Sacramento River at Bend Bridge: Maximum water temperature was 63 degrees F and occurred in September. The highest mean water temperature was 60.9 degrees F and occurred in September.

4.2.3 Dissolved Oxygen

Figure 4.3: Daily Dissolved Oxygen (mg/L) at Sacramento River at Bend Bridge (BND) in July through December 2021 and 10-year average.

Table 4.3: Mean, Maximum, Minimum Monthly Dissolved Oxygen (mg/L) at Sacramento River at Bend Bridge (BND) in July through December 2021 . Days less than 6 mg/L indicates the number of days per month that experienced at least 1 hour where DO was less than 6 mg/L.
Year Month Station Mean Min Max Days < 6mg/L
2021 July BND 11.8 1.2 17.5 2
2021 August BND 10.3 1.7 29.7 12
2021 September BND 3.5 0.1 10.9 30
2021 October BND 10.3 0.3 13.5 5
2021 November BND 10.9 3.4 15.5 1
2021 December BND 12.2 11.1 13.6 0

Summary

  • Sacramento River at Bend Bridge: Minimum dissolved oxygen was 0.1 mg/L and occurred in September. The lowest mean dissolved oxygen was 3.5 mg/L and occurred in September.

4.2.4 Turbidity

Figure 4.4: Daily Turbidity at Sacramento River at Bend Bridge (BND) and Red Bluff Diversion Dam (RDB) in 2021 and 10-year average between July and December. Turbidity data have not undergone QC, other than values filtered to less than 300 NTU.

Table 4.4: Mean, Maximum, Minimum Monthly Turbidity (NTU) at Sacramento River at Bend Bridge (BND) and Red Bluff Diversion Dam (RDB) in July through December 2021
Year Month Station Mean Min Max
2021 July BND 76.0 0.5 2565.5
2021 August BND 30.3 0.1 1310.7
2021 September BND 741.1 0.1 2621.3
2021 October BND 182.8 1.3 1140.2
2021 November BND 46.9 1.0 1138.1
2021 December BND 73.8 3.6 990.1
2021 July RDB 11.6 9.6 13.5
2021 August RDB 11.1 9.0 13.2
2021 September RDB 8.8 6.0 11.5
2021 October RDB 9.5 5.2 13.2
2021 November RDB 8.6 6.4 10.9
2021 December RDB 10.2 5.9 14.4

Summary

  • Sacramento River at Bend Bridge: Minimum turbidity was 0.1 FNU and occurred in August and September. The lowest mean turbidity was 30.3 FNU and occurred in August. Turbidity was below average in parts of August and September and similar at other times of the season.
  • Red Bluff Diversion Dam: Minimum turbidity was 5.2 FNU and occurred in October. The lowest mean turbidity was 8.6 FNU and occurred in November. Turbidity was below average between September and mid-December and similar at other times of the season

4.3 Biological Response

4.3.1 Fry abundance

Fry abundance (JPI) is calculated by Red Bluff USFWS by calculating the sum of: - fry passage from rotary screw trap data, and - estimated smolts and pre-smolts that pass RBDD, which are converted to fry-equivalents by applying the inverse of the fry-to-smolt survival rate (new method used as of BY2019; Voss and Poytress 2022).

4.3.1.1 Fry-equivalent JPI

Information from the RBDD Annual Report:

  • Fry-to-smolt survival rate:
  • Estimated Passage:
    • Fry-sized juveniles:
    • Pre-smolts and smolt passage:
  • Percent fry passage to juvenile passage (fry/fry+smolts):
    • 10-year average:
    • 20-year average:
  • Fry-equivalent JPI:
    • Juvenile Production Index JPI in 2021 was below the average JPI between 2002 and 2021 at 0.779427.
    • 10-year average:
    • 20-year average:
Annual JPI from 2002 to 2021

Figure 4.5: Annual JPI from 2002 to 2021

4.3.2 Telemetry Studies

Include a subset of the data

Table of telemetry release groups Reach-specific survival to below RBDD

4.3.3 Migration Timing

Passage at RBDD:

  • First:
    • BY2021: July 02, 2021
    • 10-year median: July 06
  • Middle 50% (25% to 75%):
    • BY2021: September 16, 2021 to October 13, 2021
    • 10-year median: September 23 to November 01
  • Last:
    • BY2021: May 25, 2022
    • 10-year median: May 02
Red Bluff Diversion Dam Migration Timing

Figure 4.6: Red Bluff Diversion Dam Migration Timing

4.3.4 Stranding

A total of 383 juveniles were stranded.

Table 4.5: Juvenile Stranding in 2021
Date Section Number Section Name River Miles Count Flow (cfs) Flow Gage
2021-08-26 2 Hwy 44 Brg to A.C.I.D Dam 298-296 4 6699 KWK
2021-11-08 2 Hwy 44 Brg to A.C.I.D Dam 298-296 34 3751 KWK
2021-11-09 2 Hwy 44 Brg to A.C.I.D Dam 298-296 65 3747 KWK
2021-11-01 3 Clear Crk. Powerlines to Hwy 44 Brg 296-288 12 4982 KWK
2021-10-28 4 Balls Ferry Brg to Clear Crk Powerlines 288-276 9 5761 KWK
2021-11-03 4 Balls Ferry Brg to Clear Crk Powerlines 288-276 75 4458 KWK
2021-11-10 4 Balls Ferry Brg to Clear Crk Powerlines 288-276 27 3582 KWK
2021-11-18 4 Balls Ferry Brg to Clear Crk Powerlines 288-276 11 3268 KWK
2021-10-27 8 RBDD to Bend Brg 257-242 71 8500 BND
2021-11-01 8 RBDD to Bend Brg 257-242 20 6268 BND
2021-11-02 8 RBDD to Bend Brg 257-242 46 6824 BND
2021-11-04 8 RBDD to Bend Brg 257-242 1 5814 BND
2021-11-16 8 RBDD to Bend Brg 257-242 4 4723 BND
2021-12-18 8 RBDD to Bend Brg 257-242 2 6198 BND
2021-12-27 8 RBDD to Bend Brg 257-242 2 8980 BND

4.3.5 Condition

4.3.5.1 RBDD Size

  • Average daily fork length
    • Early migration (July to August): 29 to 49 mm
    • Middle 50% of cumulative (September 16 to October 13): 84 to 178 mm
    • Late migration: 84 to 178 mm
  • 74 % of fish migrated past RBDD as fry (<46 mm FL)
  • Average daily fork length in 2021 was 32 to 178mm compared with the 10-year average daily fork length (29.5 to 237 mm)

Figure 4.7: Fork Length Distribution in 2021 and 10-year average at RBDD RST. The yellow line at 45 mm indicates the length transition from fry to smolt.

Fork Length Distribution over Time, RBDD RST

Figure 4.8: Fork Length Distribution over Time, RBDD RST