2 nd MEETING OF IFAECI (UMI 3351) Buenos Aires, Argentina, April 25 th 2011

1. Numerical Modeling and Observation of the Fine Sediments inthe Rio de la Plata EstuaryClaudia G. SimionatoCIMA/CONICET-UBA 2nd MEETING OF IFAECI (UMI 3351) Buenos Aires, Argentina, April 25th 2011

2. Outline • History of the cooperation France-Argentina-Uruguay • Reasons to study and model sediments • Achievements of the FREPLATA/FFEM Project • Pending scientific questions • Actions to increase cooperation • Ongoing projects and submitted proposals • What possibilities we see in the frame of the UMI

3. This cooperation starts as an initiative of IFREMER which manifested interest in applying its large experience in sedimentological observation and modeling to the Río de la Plata

4. Efforts to understand processes in the Río de la Plata had already started in the frame of the FREPLATA I Project, but sedimentology was not included yet

5. The contact between IFREMER and the regional research centers with interest and potential started

6. A proposal oriented to begin studies on sedimentological processes was submitted to the French Fund for the Global Environment (FFEM) and a budget of around €1,200,000 was approved CARP CTMFM

7. Why the study of the fine sediments dynamics is a key scientific issue? Social and environmental impacts

8. Contamination

9. Sediments moved by the flow are the main source of contaminants, particularly heavy metals.

10. In the MTZ sediments (and contaminants) are accumulated at the bottom  flocculation, reduction of the current speed?

11. Sediments are then resuspended by tides, currents and waves and contaminants enter in the trophic chain, with impact on fishes and people

12. 2. Dredging:

13. The entrance channels to the harbors of Buenos Aires and Montevideo demand continuous dredging

14. Optimization of the dredging operations is an important issue, which demands the understanding of the sedimentological dynamics

15. Ecological problems what to do with the highly contaminated muds dredged on harbors?

16. 3. Degradation of coasts and wetlands:

17. Samborombóm Bay is one of the most important wetlands of the region

18. It houses a rich ecosystem in which a large number of species of crabs, fishes, turtles and migratory birds live. It is also the nursing area for a number of species commercially fished.

19. Ongoing projects show that the bay is being eroded at very high rates, apparently by changes in the wind and waves climate

20. The fine sediment dynamics is directly related with the erosion of these shallow areas

21. Also, the shallow areas of the internal part of the system, where Buenos Aires is located, are object of large erosion and environmental pressure because of anthropogenic actions.

22. The Paraná River Delta progresses over the Río de la Plata. At the present growing rates it will be very close to Buenos Aires at the end of this century.

23. This morphological evolution will cause impacts on the uses of the Río de la Plata: drinking water, sailing, amusement, dredging, etc.

24. It will affect, particularly the Mitre Channel (access to Buenos Aires Port). The consequences of the changes can be mitigated only with planning, what needs as primary information the understanding and modeling of the sedimentological processes.

25. Primary production:

26. Turbidity is the main limitation to the phytoplankton grow. Therefore the modeling of the population dynamics rely on a proper modeling of the sedimentological variables.

27. 5. Fisheries:

28. Environmental conditions have major influence on the distribution and structure of the species in the Río de la Plata.

29. A connection (it is not clear yet whether this is causal or casual) is observed between the spawning regions and the turbidity front.

30. Understanding the relationship between the environment and the fisheries is crucial for suggesting protection and conservation plans in an ecosystemic management.

31. 6. Bentonic organisms:

32. ´The bentonic organisms are very dependent upon the bentonic environment. Therefore, the distribution of sediments determines in a large extent the diversity in a region.

33. The morphodynamical evolution by natural causes or anthropogenic action can, therefore, have a large impact on the biodiversity of the estuary

34. Understanding and modeling sedimentological processes is not easy… The aim of the FREPLATA/FFEM project was to set up the capabilities for state of the arts sediments modeling at the scale of the basin

35. Sedimentological processes are many and very complex: transportation, decantation, flocculation, saltation, resuspension, consolidation…Its modeling demands understanding and good modeling capabilities of the hydrodynamics(tides, waves, currents, density field)In contrast with the hydrodynamical processes, which obey to universal physical laws, sedimentology is highly dependent on the site  need of a large number of observations

36. The Río de la Plata presents its own challenges 230 km 320 km 50 km Very large and shallow Large runoff Enormous solid discharge In contrast with most of estuaries, highly sensitive to wind variability

37. In the frame of the FREPLATA/FFEM project, the approach was integral

38. Working groups Hydrosedimentological modeling: IMFIA, CIMA, INA, IFREMER Waves modeling: SHN Data acquisition: SHN, SOHMA, INIDEP (cooperation of IFREMER, CIMA and IMFIA) Data analysis: INIDEP, SHN, CIMA, IMFIA, INA, IFREMER

39. What advances were done in the frame of the Project?

40. 1. Formation of human resources Fellowship for a PhD student at CIMA (Diego Moreira) Receiving a postdoc from IFREMER (at CIMA) (Caroline Tessier) Courses at Facultad de Ciencias Exactas y Naturales de la Universidad de Buenos Aires (FCEN-UBA) training to students and researchers on sediments dynamics, observation, modeling and metrology (Florence Cayocca, Francis Gohin, Pierre Le Hir, Valerie Garnier, Michel Repecaud)

41. 2. Collection of all the historical data and construction of a data repository • Tides • Current • Waves • Bottom and suspended sediments • Bathymetry • Others…

42. 3. Acquisition of a unique data base of hydrosedimentological variables • Fixed stations  time series with high temporal resolution • Oceanographic cruises  synoptic view and high vertical resolution; installation and maintenance of the instruments • Satellite observations  longer term data; synoptic view

43. Fixed stations: Torre Oyarvide Pilote Norden Pressure (waves) Temperature, salinity Turbidity SMATCH TT

44. Oceanographic buoy The buoy measures: meteorological variables temperature, salinity, turbidity, oxígen, chlorophyll-a, currents (ADCP) Data are currently received at CIMA

45. 7 oceanographic cruises with 26 stations each (CTD, chlorophyll, turbidity, water and sediments samples) 1 included yo-yo stations

46. Remote sensing data calibration and analysis MODIS and SeaWifs in 1 km y 250m, calibrated to SM and chlorophyll-a with IFREMER’s algorithms Data were analyzed to observe the main patterns of variability in the estuary http://www.ifremer.fr/nausicaa2/rioplata

47. 4.Laboratory experiments Understanding the consolidation processes

48. 5. Implementation of the IFREMER’s hydrosedimentological MARS model for the Río de la Plata Hierarchy of one-way nested models

49. The advances in numerical modeling have been: • Installation of the model at CIMA, INA and IMFIA • Validation of the hydrodynamics (tides and wind effect) • Precalibration of the sedimentology and first sensitivity studies • First process oriented simulations • We can provide a copy of the final report to those who might be interested

50. Main achievements of FREPLATA/FFEM project • Developing of a network of researchers and institutions  good dynamics among participants and excellent possibilities for cooperative and synergic multidisciplinary research • Acquisition of a unique data base of hydrosedimentological variables • Formation of human resources • Installation of capabilities in data acquisition, metrology and numerical modeling of hydrosedimentological processes in several institutions of Argentina and Uruguay