ABSTRACT
This study highlights the importance of urban hydrogeological mapping, under a geoenvironmental perspective, as well as the vital significance of an inventory of potential surface contamination sources, as useful tools for understanding the potential contamination of the Porto City groundwater systems (NW Portugal, Iberian Massif). Paranhos spring horizontal galleries catchworks (Arca d’Água sector; ca. 1 km extension and a −20 m of depth) was one of the main water supplies to Porto city for more than five centuries and, nowadays, these waters are still appropriate for irrigation uses. Therefore, the following steps were performed: i) for the characterisation of the underground area, mainly granitic rocks, subsurface geological and hydrogeological mapping were carried out; ii) hydrogeological, hydrogeochemical and ecotoxicological techniques were used to describe the groundwater; iii) potential sources of groundwater contamination located in the surrounding areas of the galleries catchworks were registered and mapped.
