Origin of the springs of Costa Verde beach in Lima Peru

This paper tries to determine the origin of springs on the Costa Verde beach, located in the district of Barranco, Miraflores and Magdalena, province of Lima, Peru. These springs emerge near the shoreline, from the lower layers of a 80 meter high cliff. They have survived the process of urbanization of agricultural land, started in the early 70, which decreased the water table aquifer of Lima, and wiped the water leaks from the cliffs. To identify the source of the springs, isotopic, physical, chemical and bacteriological analysis was carried out for samples from five springs. The isotopic concentrations in waters from Costa Verde springs are depleted compared to those obtained for Lima aquifer waters, which is recharged by infiltration of the Rimac River. The measured values of those concentrations suggest that water from the Costa Verde springs should come from a direct recharge in the upper and middle basin, due to infiltration of rainfall or the river at an altitude of about 3600 m. Conductivity and temperature, measured in situ, are similar to those obtained on Lima aquifers. The laboratory analysis showed no significant levels of total or fecal coliform, discarding possible leakage from Lima sewerage.