1. Studies of Estuarine Hydrography Originally: Environmental Studies for sustainable management of two bays of semidesertic climate: El Tobari y Lobos, Sonora, Mexico. Now: Environmental Studies for sustainable management of a bay of Semidesertic Climate: El Tobari. Esther Cruz-Colin, Juan Antonio Delgado, Arnoldo Valle-Levinson, & Stephen Monismith

2. Objective Complete hydrodynamic behavior and physical and chemical characterization for El Tobari and Lobos, two coastal lagoons/estuaries, with the purpose of giving a solid basis for their management and sustainable development (or restoration).

3. Specific objectives Implement periodic monitoring in both lagoons to detect changes in physical conditions (salinity, circulation,..) which may be important for nutrient cycling, larval transport etc. Develop first picture of how circulation patterns in these shallow estuaries respond to winds, tides, and evaporation - typical for desert-climate coastal lagoons Develop data needed to model these systems

4. Mean = 1.2 cm/s Mean = 2 cm/s North Mouth South Mouth January 2000 data antecedents

5. January February 2000 antecedents

6. February January 2000 Moored south mouth

7. Work to date We carried an intensive field experiment at each of the mouths of the Tobari in which we measured salinity (CTD) and velocity (ADCP) transects throughout a 24 hour period using small boats. Additionally we collected time series of salinity, temperature and depth for one month periods at both mouths.

8. Us schedule of measurements Paredon Colorado Tony’s roof

9. The transect boat ADCP gps Laptop for real time tools amarre

10. Camp Tecate

11. Captains Chuy and Peter

12. It takes a village to launch a boat..

13. The buoys were easier to see in the daylight

14. The iron men…

15. Boca norte Boca sur Bathymetry (done with ADCP/GPS)

16. Bathymetry

17. Wading birds near Boca Norte

18. October 2002: Boca Norte Transects 1 2 3 4

19. Transect data analysis Harmonic analysis (least squares) to extract mean flow, M2 (semidiurnal) and K1 (diurnal) tides from transect data Look for spatial variability of flows

20. Mean velocities: Transect 1 Out In Transverse variability important for fluxes

21. Tidal velocities: Transect 1

22. Mean velocities: Transect 2

23. Tidal velocities: Transect 2

24. Mean velocities: Transect 3

25. Boca Sur transects: March 2003 Wavy! (muy peligroso) 3 4 2

26. Mean velocities: Transect 3

27. Tidal velocities: Transect 3

29. A front in the south mouth

30. Manuel manually does the CTD

31. Temperature (ºC) Salinity (ups) ebb flood end ebb start ebb start flood

32. Summary The patterns of circulation are predominantly tidal – Are mean currents (and exchanges) produced by rectification (bathymetry is crucial) or by variations in density (or both)?

33. Next steps: Finish processing 2002/03 data More field work in El Tobari South Mouth Integrate with Mike’s nutrients and phytoplankton work 3D model of El Tobari (remove causeway!) Lobo (harder logistically) New NSF proposal (see next talk)

34. The good news is… To continue this project and to accomplish the specific objective for this studies we will get funds from Consejo Nacional de Ciencia y Tecnología (CONACyT)- Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT). amount: $413,816.00 pesos = $35,984 dlls