Modelagem ambiental e indicadores de pressão nos recursos hídricos da alta bacia do Rio Vermelho (Goiás)

Abstract

Researches in Watersheds have become increasingly constant, as spatial cutouts of geographic analysis, for the assessment of the level of environmental degradation and identification of the potential and vulnerabilities of the behavior of a natural system, anthropized or not. Such studies make possible more and more conditions for having good diagnoses focused on the planning and management of these areas. In this context, geoprocessing tools have been important for the procedures of modeling environmental systems, helping to define indicators and diagnose the consequences of the inappropriate use of water resources. In this way, this work aimed to develop a spatial pressure index on water resources for the Alta Bacia do Rio Vermelho, GoiásGO, (ABRV) – a Watershed –, in the perspective of the integrated landscape analysis and based on the characteristics of the physical environment and use and land cover. The Watershed makes up the drainage system of the Araguaia River Watershed; it is located in the western portion of the state of Goiás, occupying an area of 2.107 km²; and its territory consists of the municipalities of Goiás and Itapirapuã. In order to achieve the proposed objectives, spatial and temporal assessments of the potential for land use and cover and the density of vegetation cover (SAVI) were made; a mapping of the description of the slopes, geomorphology and hydrogeology; a characterization of climatic and meteorological aspects and, finally, an elaboration of the pressure index in water resources, based on the correlation of the variables raised, using the AHP (Analytic Hierarchy Process) multicriteria analysis. The results obtained by applying the variables in the AHP method presented the final map of the Watershed (ABRV), with classes that ranged from very high (5,93%), high (6,73%), moderate (18,4%), low (41,16%) and very low (28,28%) in the Pressure Index in Water Resources. It was observed that the phenomena triggered in the Watershed, in relation to the water crisis condition, are related to the overexploitation of water resources, the alteration of drainage channels, the occupation of APPs (Permanent Preservation Áreas) and the replacement of natural vegetation by pastures. These conditions associated with the potential for recharge and flow rate, attributed to the elements of the physical environment, explain the scenario of water scarcity that worsens during the drought period. Thus, it is of high importance for regional environmental planning and for good management to preserve and conserve the natural resources of the basin as a whole, in addition to shared water management.