1. U.S. Department of the Interior U.S. Geological Survey Bathymetric Surveys on Ponds 3, 4, & 5, Napa-Sonoma Marshes U.S. Geological Survey John Y. Takekawa, Lacy M. Smith, & Nicole D. Athearn

2. Bathymetric Survey Overview  Goal: Document geomorphologic changes that have occurred since restoration of tidal flow  New baseline data – Post-Breach Ponds 4 and 5  Comparable data  Pond 3: 2001 (Towill) vs. 2009, 2001 vs. 2005, 2005 vs. 2009  Ponds 4 & 5: 2001 (Towill) vs. 2009  Additional mapping of original South Slough breach, all pond breaches, and pond islands.

3. Bathymetry Survey Methods Pelican Case with Navisound RTK Antenna Console with laptop & RTK Transducer

4. Bathymetry Survey Methods  200 m East-West & North-South transects Pond 3 Pond 4

5. Bathymetry Survey Methods  South Slough and Breaches

6. Pond 3 ~ 2002 South Slough Breach  Mean elevation 2006: -3.122 ± 0.032 m (mean ± SE) NAVD 88  Mean elevation 2009: -3.108 ± 0.031 m 20062009

7. Pond 3 ~ 2002 South Slough Breach  Net sediment gain of 46 m 3 or a 1.4 cm thick layer across the area

8. South Slough  Mean elevation of South Slough region only: -2.85 ± 1.52 m

9. Pond 5 ~ Current Elevation  Mean elevation: 0.85 ± 0.003 m (mean ± SE) NAVD 88  Elevation Range: -1.50 to 1.53 m

10. Pond 5 ~ 2001 - 2009  2001: 0.78 ± 0.003 m (mean ± SE)2009: 0.85 ± 0.003 m

11. Pond 5 ~ Change in Elevation  Net sediment gain: 217,625 m 3  7.6 cm layer of sediment throughout the pond

12. Pond 4 ~ Current Elevation  Mean elevation: 0.81 ± 0.004 m  Elevation Range: -2.1 to 1.97 m

13. Pond 4 ~ 2001 - 2009  2001: 0.82 ± 0.003m (mean ± SE) 2009: 0.81 ± 0.004m

14. Pond 4 ~ Change in Elevation  Net sediment gain: 19,700 m 3  5.4 cm layer of sediment throughout the pond

15. Pond 3 ~ Current Elevation  Mean elevation: 1.05 ± 0.003 m  Elevation Range: -1.60 to 1.90 m

16. Pond 3 ~ 2001 to 2009 2001: 1.17 ± 0.002 m (mean ± SE)2009: 1.05 ± 0.003 m

17. Pond 3 ~ Elevation Change 2001-2009  Net sediment loss: 594,900 m 3  12 cm layer of sediment throughout the pond

18. Pond 3 ~ 2005 - 2009 2005: 0.96 ± 0.002m (mean ± SE)2009: 1.05 ± 0.003m

19. Pond 3 ~ Change in Elevation 05-09  Net sediment gain: 473,800 m 3  9 cm layer of sediment throughout the pond

20. Vegetation  See Google Earth

21. Summary

22. Future Research  Additional bathymetric surveys over time  Bathymetric survey on 9 & 10  Aerial and Ground vegetation surveys  Elevation survey of colonizing plants  Continued monitoring of bird pond use

23. Acknowledgements  Funding provided by USGS and CA State Coastal Conservancy  Project support provided by: I. Woo, K. Spragens, K. Thorne, J. Shinn, A. Brand, K. Brailsford, C. Daggett, P. Gibson, T. Edgarian, S. Bishop, S. Piotter, K. Hirsch, and H. Haselbach