BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA Vol 64, Núm. 2, 2012, P. 229-241 http://dx.doi.org/10.18268/BSGM2012v64n2a8

Tasas de erosión e índices geomorfológicos en tres cuencas costeras al sur de la península de Baja California, México

Erosion rates and geomorphological indexes in three coastal basins south of the Baja California peninsula, Mexico

 José Octavio Navarro Lozano^1,*, Enrique Nava Sánchez², Enrique Troyo Dieguez³, José Luis Cadena Zamudio⁴

 ¹Comisión Nacional del Agua (CONAGUA), Subdirección de Asistencia Técnica-Operativa. Chiapas No. 2535, Col. Los Olivos, CP 23040, La Paz, BCS.
² Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas. Av. Instituto Politécnico Nacional s/n, Col. Playa Palo de Santa Rita, Apdo. Postal 592. CP 23096, La Paz, BCS.
³ Centro de Investigaciones Biológicas del Noroeste, S.C., Mar Bermejo No. 195, Col. Playa Palo de Santa Rita, Apdo. Postal 128, CP 23090, La Paz, BCS.
⁴ Universidad Autónoma del Estado de Hidalgo, Instituto de Ciencias Básicas e Ingeniería, Área Académica de Ciencias de la Tierra y Materiales. Ciudad Universitaria, Km 4.5 Carretera Pachuca – Tulancingo, Col. Carboneras, CP 42184, Mineral de la Reforma, Hgo.

 ^* 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

Coastal drainage basins in the southern part of the peninsula of Baja California are an important part for the stability of the littoral cell system of the coast in Baja California, because they are the major sediment sources. Migriño, El Salto and El Tule watersheds are vulnerable to erosion due to the steep slopes and geographic location because in this part of the peninsula rainfall associated with summer hurricanes has a mayor influence. Using the RUSLE equation (Revised Universal Soil Loss Equation) and geomorphologic indexes, obtained by GIS techniques, we assessed the spatial distribution of erosion rates and its relationship to lithology, geomorphic features, soil distribution and structural patterns. This allowed us to know the control that soil distribution and geomorphic features exert on the distribution of erosion rates within each drainage basin. Moderate (0.1 to 0.5 Mg ha^-1 year^-1) to high (0.5 to 2 Mg ha^-1 year^-1) erosion rates are associated to slopes equal to or greater than 15°(mountain slopes), and Litosol-Regosol types; low erosion rates (0 – 0.1 Mg ha^-1 year^-1) are associated to slopes of less than 5º (gentle hill slopes and plains), and Regosol types. Analyses of geomorphologic indexes show that river drainage basins are young, and are associated to moderate or negligible neotectonic activity, as evidenced primarily by structural control in the upper basin. Changes in geomorphologic indexes in the middle and lower basins, where erosion and depositional processes are occurring, indicate little structural control.

Keywords: Erosion rates, structural control, San Lucas Bay, RUSLE, sediments.