Risk Mapping of Water Supply and Sanitary Sewage Systems in a City in the Brazilian Semi-Arid Region Using GIS-MCDA

Abstract

It is essential to visualize water scarcity as a result of an inappropriate process of appropriation and the use of natural resources. This understanding has been gaining more and more prominence in studies in Brazil and also in the world. In this context, this research aims to map the risk of water shortages and sewage insufficiency in a Brazilian semi-arid city using GIS-MCDA. The secondary data used in this research were collected from IBGE, Compesa, and the City Hall of Caruaru and were processed using the QGIS 3.12 Bucareşti software. The Pernambuco Tridimensional database and the Analytical Hierarchy Process method were used in the process to generate the maps. After collecting and analyzing the data, it was seen that, according to the water shortage risk map, seven neighborhoods had a “Very high” risk, in which the criteria with the greatest weight were the distance from distribution reservoirs, the main supply network and altimetry. The map of the degree of sanitary sewage insufficiency showed that four neighborhoods have a “Very high” degree; these neighborhoods are far from the main sewage network and from sewage treatment stations and have the lowest rates of households served by the system. Such characteristics need to be highlighted in the planning and implementation of water and sewage services. Thus, it is concluded that the use of high-resolution spatial databases for the planning of urban services, as carried out in the present work, provides a greater level of confidence for solutions that can be implemented in the expansion of service networks to the population.