Origin and residence time of water in the Lima Aquifer

TL;DR

This study investigates the origin and residence time of water in the Lima Aquifer by analyzing isotopic compositions and historical flow data, providing insights into water sources and age for sustainable management.

Contribution

It combines hydrological data with isotopic analysis to determine water sources and residence times in the Lima Aquifer for the first time.

Findings

Water in the aquifer is primarily recharged by the Rimac River.

Estimated water residence time ranges from several years to decades.

Isotopic signatures confirm the origins of well waters from local recharge.

Abstract

The 8 million inhabitants of the coast Lima City are supplied with water from Rimac and Chillons rivers and water wells in the Lima aquifer. Historics of Rimac River flow and static level of water level in wells are correlated in order to calculate residence time of water since the aquifer is recharged by Rimac River until water reaches a well located 12 km farther, in Miraflores district near sea. Relative abundances of 2H and 18O are used to identify origins of waters from those wells. 3H and 14C contents, respectively, are used to estimate ages of waters.