Geotechnical investigation of land in the municipality of Descalvado (SP, Brazil) for selection of suitable areas for residuary water treatment lagoons

Abstract

Selecting suitable areas for the location of effluent treatment lagoons requires detailed analysis procedures of
various attributes of the physical environment, in order to avoid environmental degradation, hence protecting it
against the possible impacts that may result from the implementation of such lagoons. To indicate potentially
suitable areas for the location of residuary water stabilization lagoons, a map was drawn up on a scale of 1:50,000,
based on the cross-referencing of representative cartographic documents describing the attributes of the physical
environment (textural classification, declivity, common toxicity criteria (CTC), permeability, surface drainage,
lithology, clay mineralogy, depth of the saturated zone, and depth of the rock substrate) in the municipality of
Descalvado (SP, Brazil). The AHP technique of multi- criteria analysis was used herein, with paired analysis of the
attributes, enabling the information of the physical environment to be treated in order to obtain a result that is more
compatible with the real conditions found in the surroundings. The final result was the identification of the following
classes of suitability, 1% of urban areas and highways; 27% of forbidden areas; 13% of favorable areas; 11% of
moderate areas; 47% of severe areas; and 1% of restrictive areas.