San Joaquin River Bedload Sampling summary January 4 and 5, 2011 April 1 and 2, 2011 Ledger Island

Purpose of Bedload Sampling at Ledger Island Contribute to understanding mobility thresholds of different grain sizes (sand  gravel) Estimate sand transport rates in Reach 1A to evaluate fine sediment budget, will inform future fine sediment management for spawning and rearing habitat Estimate coarse sediment transport rates in Reach 1A to inform future spawning gravel augmentation needs

Ledger Island bedload sampling location

January 4-5 and April 1-2 Friant Dam Flood Control Releases 4,690 cfs7,000 cfs 8,090 cfs 8,060 cfs

Single Ledger Island sample: 4,000 cfs

Single Ledger Island sample: 6,000 cfs

Sample Processing Bedload discharge < 2mm Bedload discharge <8mm Bedload discharge between 2mm and 8mm Bedload discharge >8mm Total bedload discharge

Bedload data

Sample Analysis 4 passes at 4,690 cfs 1 pass at 5,200 cfs 1 pass at 5,800 cfs 4 passes at 7,000 cfs 5 passes at 8,090 cfs 5 passes at 8,060 cfs 4 passes at 4,000 cfs and 6,000 cfs averaged into two samples 5 passes at 8,090 cfs and 8,060 cfs averaged into two samples

Total Bedload Transport Data

Bedload Transport Data <2mm

Bedload Transport Data >2mm Largest grain in transport =115 mm at 8,060 cfs

Water Surface Slopes

Next Steps Prepare short tech memo summarizing methods and results Send bedload data to SJRRP (Erin?) for distribution to Program technical staff and consultants Technical discussion of additional sampling needs – Sampling location – Target flows Considerations for RA/TAC Recommendations