Middle Fork Project AQ 3 – Macroinvertebrate and Aquatic Mollusk Technical Study Report Overview

1. Middle Fork ProjectAQ 3 – Macroinvertebrate and Aquatic Mollusk Technical Study Report Overview April 21, 2008

2. Study Objectives • Document the BMI community in the peaking reach and compare to adjacent bypass and comparison reaches to characterize general habitat conditions. • Sample the BMI community at long-term USDA-FS sampling sites to supplement existing data sets. • Document BMI community in bypass reaches downstream of each large reservoir.

3. Study Objectives • Document the BMI community in areas with known water quality issues, if any, as determined in the AQ 11– TSR. • Document the seasonal density and size distribution of drifting macroinvertebrates in selected bypass reaches and the peaking reach for input to bioenergetics growth and habitat modeling (2009 AQ 5-TSR). • Determine presence or absence of 3 special-status mollusk species and identify potentially suitable habitat for these species (2009 AQ 3-TSR).

4. Macroinvertebrate Study Objectives and Related StudyElements and Reports Study Objectives Document BMI community in the peaking reach and compare to adjacent bypass and comparison reaches to characterize general habitat conditions. Sample BMI community at long-term USDA-FS sampling sites to supplement existing data sets. Document BMI community in the bypass reaches downstream of each large reservoir. Document BMI community in areas with known water quality issues, if any are identified in the AQ 11 - TSP. Determine presence or absence of three special-status mollusk species and identify potentially suitable habitat for these species. Document seasonal density and size distribution of drifting macroinvertebrates in selected bypass reaches and the peaking reach for input to bioenergetics growth and habitat modeling. Conduct 2007 Field Surveys Conduct SWAMP Benthic Sampling Conduct CSBP Benthic Sampling at the Ralston Afterbay Sediment Management Project Monitoring Sites Conduct Drift Sampling Document 2007 Findings in this Macroinvertebrate Report Consult with Aquatic TWG Discuss Contingency Sampling Based on Water Quality Results If Necessary, Develop Recommendations and Prepare Contingency Studies Document 2007 Findings in the Bioenergetics Report (2009) Complete 2008 Mollusk Field Studies and Contingency Studies (if necessary) Document 2008 Mollusk and Contingency Study Results in Macroinvertebrate Report (2009)

5. Macroinvertebrate Study Sites 14 SWAMP Sites 7 RASMP (CSBP) Sites

6. Multi-metric index of biotic integrity (IBI) (Rehn 2008) ET taxa richness Percent intolerant individuals Percent tolerant individuals Percent Non-insect taxa Percent predator individuals Percent scraper individuals Shannon diversity Individual metrics consistent with the RASMP (2000-2006) Invertebrate density Taxa richness EPT ratio Percent Chironomidae California Tolerance Value Functional feeding groups Dominant taxa BMI Metrics

7. Survey Results • Longitudinal Trends in BMI Community Metrics • Comparison of Peaking Reach and Adjacent Bypass and Comparison Reaches • Above and Below Diversions • Bypass Reaches Below Large Reservoirs • Long-term BMI Sampling Sites

8. Longitudinal Trends in BMI Community Metrics • Hydropower IBI scores are higher at higher elevation and colder water sampling sites than at the low elevation and warmer water sampling sites.

9. Comparison of Peaking Reach with Adjacent Bypass and Comparison Reaches • Hydropower IBI and individual metric scores in the peaking reach (RM 20.9 to RM 4.8) are similar to sites in the Middle Fork American and Rubicon Rivers immediately upstream of Ralston Afterbay and comparison streams, although some variability of individual metrics occurs.

10. Comparison of Peaking Reach with Adjacent Bypass and Comparison Reaches • Compared to the comparison sampling sites, the downstream peaking reach sampling sites had: • Lower California Tolerance Values (better habitat) • Similar or higher BMI densities • Similar EPT Index values • Slightly lower taxa richness • More collector-gathers and collector-filterers and fewer scrapers

11. Comparison of Peaking Reach with Adjacent Bypass and Comparison Reaches • Hydropower IBI scores and individual metrics are low at MF24.4 and MF36.2 compared to adjacent bypass and comparison sites.

12. Above and Below Diversions • In 2007, hydropower IBI scores were slightly higher upstream from the diversions than downstream.

13. Bypass Reaches Below Large Reservoirs • Hydropower IBI scores are high and within the range of those observed in unimpaired river reaches above hydropower reservoirs by Rehn (2008).

14. Long-term BMI Sampling Sites • RASMP Locations (2000-2007)

15. Long-term BMI Sampling Sites • RASMP Locations (2000-2007): Functional Feeding Groups

16. Long-term BMI Sampling Sites • South Fork Long Canyon Creek • Hydropower IBI scores have slightly increased since 1999.

17. Long-term BMI Sampling Sites • Duncan Creek • Hydropower IBI scores have varied over time.