Avaliação da vulnerabilidade natural à contaminação dos recursos hídricos subterrâneos no município de Faxinal do Soturno, RS

Abstract

The current scenery leads to the need of the knowledge of the dimensions of the groundwater hydrics reservations, as well of an appropriate planning of occupation of the soil, for the protection and rational use of those resources. This work has potentially as objectives to investigate the activities pollutants of the groundwater hydrics resources in the municipal district of Faxinal do Soturno, RS, by the study of the index of natural vulnerability to the contamination and to subsidize programs of administration of this resources. The information on the groundwater wells were obtained through the electronic register already existent of users of groundwaters of SIAGAS (System of Information of Underground Waters), available in the electronic address of CPRM (Company of Researches of Mineral Resources), in the municipal city hall and through field work. A georreferenciade database was elaborated with information regarding to 21 groundwater wells, which possessed the data for application of the Method "GOD" for determination of the index of natural vulnerability of contamination proposed by Foster and Hirata (1993) and Foster et al. (2003), cartography represented through the software Surfer 8.0. It was verified that in the municipal district in analysis the groundwater wells possess variation of the altitude of the land in the "mouth" of the wells of 60 m the more than 421 m. Already the variation of the depth is from 20 to 230 m, and the depth of the potenciometric surface is of 40 to more than 190 m, presenting 4 main flow directions. A, in the northeast area and east of the municipal district, that it is addressed certainly for the arroio Trombudo, in the area west of the municipal district happens directions of flow of groundwater addressed for the arroio Guarda-Mor of customs and Ivorá. In the central area, it happens a direction of groundwater flow addressed for rio Soturno and their tributaries, standing out the arroio Jiuliani and arroio Refatti. The variation of the static level is from 0 to 36 m, and in what refers to the vulnerability, there is 1 well inserted in the despicable class, 2 wells in the average, 6 wells in the discharge and 1 well in the class of extreme vulnerability, wells were not verified inserted in the classes of low vulnerability. As activities potentially pollutants, it was investigated the agricultural activities, the cemetery, polluted courses of water, deposit of residues and put of services, which they could be delineated in a reliable way, being verified the lack of legal mechanisms of control and monitoring of some of these activities. It is waited that the results obtained in that work can aid for the implantation of preservationists measures and of planning on the part of the public organs, with views to the rational use of the natural resources.