Geomorfologia e reabilita����o de ��reas degradadas por eros��o com t��cnicas de bioengenharia de solos na bacia do rio Bacanga, S��o Lu��s, Maranh��o

Ph.D. thesis, Federal University of Rio de Janeiro (in Portuguese, with English Abstract) / Tese (Doutorado em Geografia), Programa de P��s-Gradua����o em Geografia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 250 pp. Director of Studies: Professor Antonio J.T. Guerra. Supervisor: Michael A. Fullen. Portuguese abstract in attached file.The research analysed the geomorphological characteristics of the Bacanga basin of S��o Lu��s municipality. Basin characteristics were related to highly developed erosion processes. The approach considered the identification of environmental fragility classes, the monitoring of an experimental station and the rehabilitation of a degraded area using soil bioengineering techniques. The adopted methodological procedures included: 1. Cartographic and bibliographic surveys. 2. Mapping of the hypsometry, slope, land use, rainfall index and geomorphology of the Bacanga basin, along with analysis of the morphostructure and morphosculture of the Gulf of Maranhense and environmental fragility mapping. 3. Establishing an experimental station with two replicate erosion plots and measuring the following parameters: vegetation cover index, soil surface changes using erosion pins, soil matric potential, runoff and sediment loss. 4. The rehabilitation of Sacav��m gully using soil bioengineering techniques (using geotextiles constructed from palm leaves of the Buriti tree). Mapping showed that identified gullies are located on the plateau edges of the basin and are very fragile environments. The greatest interval of vegetation cover index development was between February (0%) and March (33.35%) (both 2009), whereas the smallest difference was 5.31%, between May (75.88%) and June (both 2009) (81.19%). The difference of erosion/deposition pin data within the bare and vegetated soil plots was significant using the non-parametric Kruskal-Wallis test (P <0.001). The results obtained from tensiometers at 10, 20, 40 and 60 cm depth showed a significant difference (P