Mapeamento geológico-estrutural e hidrogeológico do município de Acarape - CE : avaliação de critérios estruturais na hidrogeologia de terrenos cristalinos

Abstract

This work deals with the analysis of the structural aspects able to influence on tube wells flow located in the municipality of Acarape, State of Ceará. The low flows of the wells in the municipality are often reflections of regional geo-environmental characteristics, such as: lithology, low rainfall and small thickness of the mande of change. Associated with this, there is a large number of wells built whose locations they didn't take into account the conditions of occurrence of underground water, reflected in low flows registered in the registered wells. A quantitative analysis based on the data of the registered wells, in the interpretation of the guidelines from the SRTM image and explored through aeromagnetometric surveys, thematic maps of lithotypes, flows, and guidelines in the field. The results showed that the majority of the wells built (58.06%) in the County has less than 3 flow, O m 3/h static levei has variable depth with 51.92% smaller than 9.0 metres, 34.61% with depths between 9.0 and 18 m and 13.47% over 18 m. The nature of the wells is dominantly non-tubular being found wells. The situation shows that 48% of the wells are in operation, 44% disabled, 7% and 1% are not fitted. The depth of the wells is, in your most, around 60 m. The magnetic lineaments interpreted match field data (foliation and rock fractures) and assist in locating water storage fractures that are often responsible for the high flow of wells in crystalline terrains. The use of SRTM imagery proved inefficient, generating a large number of guidelines that it reflected the structural lineaments fetched. The geological domain integration versus flow showed wells with high and low flow rates are located in the same domain; the integration of guidelines versus flow density showed that there are low and high flow wells located in areas of high density of lineaments. With the analysis of the hydrogeological aspects was possible to make recommendation on viable areas for leasing of wells in the study arca. The location of wells in this municipality should take into consideration the lineaments with directions ENE and NNE, which, especially when interseccionados with each other, generate good flows.