Abstract
Groundwater flow systems, into the saturated and unsaturated zones, come from differentplaces depending on the geological, structural and geomorphological configuration of thearea. Those which come from places near of recharge zone are known as local flows, andthose which come from more distant places from this area are known as intermediate andregional flows. The former have short circulation times from months to years, the latest varyfrom hundreds to thousands of years. This paper had the aim to identify and to delimit thepresence of these groundwater flow systems in the urban hydrogeological system of AburraValley –Colombia–, through the analysis of the current hydrogeological model, the variablesthat characterize groundwater flow systems and hydrochemical information. The resultswere validated through isotopic analysis. By use of hydrochemical techniques was possibleto stablish that the main processes that govern chemical composition of groundwater in theaquifer system are weathering of silicates, dissolution of ferromagnesian minerals, directionic exchange, chemical evolution of groundwater and some events of anthropiccontamination. By analyzing the variation of chloride and sulphate was found that the mainsource of these ions is in depth, from intermediate and regional flows. Zones where local,intermediate and regional groundwater flow systems are present were delimitated. Localflows are widely distributed by the study area, are recharged inside the Aburrá river basin,main source of discharge of the area, and are discharged both the slopes and valley.Intermediate and regional flows are recharged outside the Aburrá river basin and dischargedexclusively in the valley, near the axis of the river, by vertical upward flows. It wasdetermined that within the aquifer system processes of groundwater mixture from differentchemical composition are presented.