Geo-environmental Analysis of Watersheds on the Eastern Coast of the State of Maranhão, Brazil and Interface with Lençóis Maranhenses National Park

Abstract

Watersheds occupy a vulnerable position with regards to issues associated with anthropogenic changes. The state of Maranhão stands out in Brazil for its water resources. The Watersheds of the Eastern Coast of Maranhão (ECWSM) are located in the Hydrographic Region of the Western Atlantic. The present paper characterizes the physiography of the ECWSM of Maranhão, highlighting the components and natural potential (altimetry, declivity, soils, vegetation, water resources, geology and geomorphology), which were mapped using geotechnologies and secondary data. Thus, this paper provides information for the planning of socioeconomic development programs as well as land management plans. The geology, geomorphology, pedology and vegetation data were obtained from the IBGE database at a scale of 1:250,000. The Digital Elevation Model was obtained from the TOPODATA project. Water resources data were obtained from the IBGE, National Water Agency. The ECWSM analyzed were: the Hydrographic Basin System of the Rivers Itatuaba, Anajatuba, Axuí, Mapari, Periá, Grande and the Hydrographic Basins of the Negro and Preguiças Rivers. The morphological and physical attributes of the ECWSM and the relationships of ecological potential (geology, geomorphology, hydrology and climate), biological exploitation (soil and vegetation) and human actions reveal proxies of the evolution of the Holocene landscape. The natural resources and landscape of Conservation Units within these watersheds form immense nurseries for biological productivity that supports traditional economic activity. The mapping of the ECWSM contributes to the development of effective environmental zoning in the region.