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BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA http://dx.doi.org/10.18268/BSGM2009v61n1a2 |
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Comparación de modelos de transporte de sedimento en la Bahía Todos Santos, Baja California, México
A comparison between sediment transport models in the Todos Santos Bay, Baja California, Mexico
Alberto Sánchez1,*, José Carriquiry 2, Jorge Barrera2, B. Estela López–Ortiz1
1 Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, Baja California Sur, México.
2 Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California.
* This email address is being protected from spambots. You need JavaScript enabled to view it.; This email address is being protected from spambots. You need JavaScript enabled to view it..
Abstract
To determine residual sediment transport in the Bay of Todos Santos (BTS), grain size trend analysis were compared and applied utilizing models of Sunamura and Horikawa (1971), Mc Laren and Bowles (1985), and Gao and Collins(1994). The Sunamura–Horikawa model uses grain–size and sorting for comparison criteria to infer sediment transport whereas the models of Mc Laren–Bowles and the Gao–Collins use these two parameters and also asymmetry. The first two models mentioned are one–dimensional while the third model is two–dimensional. The model of Gao and Collins (1994) turned out to be most satisfactory model for determining patterns of dispersion of surface sediments. In the BTS, the pattern of dispersion showed several sediment transport tendencies. In the North zone of the bay the transport was in a SE direction (following the isobath contour of 20 m), and towards the NE (near the Island of Todos Santos). For the South zone transport displayed a NE direction, while the central region of the bay displayed a westerly transport direction. In the canyon of Todos Santos a NE trajectory was determined. The presence of currents with speeds of 0.30 ms–1 makes transport possible towards the interior part of the bay. In the external region of the bay, in front of the Islands of Todos Santos and the Peninsula of Punta Banda, the inferred transport is towards the W. For the shallow zones, the superficial circulation and the coastal transport agree with previous published results and compare well with the present work. The tide processes (current residuals or internal waves) are an important factor in the resuspension and transport of material in the deep zones of the bay. The central zone of the bay seems to be a convergence site and can give rise to particle stagnation in the bay (e.g., polluting agents).
Keywords: Bay of Todos Santos; grain size trend analysis; sediment transport; polluting agents.
