Digital elevation model as a GIS tool for the analysis of mangrove coasts. Amazon Region, Brazil

COHEN, MARCELO; LARA, RUBÉN JOSÉ; SZLAFSZTEIN, C.F.; DITTTMAR, THORSTEN

INTERNATIONAL JOURNAL OF ENVIRONMENTAL CREATION

University of Hokkaido

Lugar: Hokkaido; Año: 2000 p. 31 - 41

1343-9863

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Geographical surface data models can be created by GIS methods, which are computer-based tools for processing and displaying spatial or georeferenced information. GIS techniques were used to process and visualize topography and tidal regime data, focusing on the inundation of a mangrove ecosystem (Bragança, North Brazil). As part of the MADAM Project, a 1:1000 topographical map covering about 4 ha near the ?Furo do Chato? tidal creek was produced. Contour levels were regularly spaced at 1 m intervals between 0 and 6m, relative to the bottom of the creek at the sampling site. Due to the smooth topographical gradients found in these mangroves, this site can be considered representative of the mangrove topography in North Brazil. Acquisition of altimetric data for the elaboration of topographical map of the whole peninsula was carried out using simple devices for measuring tide elevation simultaneously at several location in an area of ~190 km2. During average neap and spring tides, ~70% and ~90% of the studied mangrove is flooded, respectively. The topographical features of the study area cause that small water level variations can produce significant changes in the inundation area. The used model approach realistically reflects geomorphology-dependent processes. It showed relationships between vegetation assemblages and topographically defined habitats, providing numerical basis for the evaluation of vegetation distribution patterns and nutrients dynamics in well-defined catchment areas. Further, it provided a link to sediment-water interactions not previously evaluated in our own investigations on creek water chemistry.