Vertical Upward Intrusion of Salt Water due to the Intensive Exploitation. Santa Fe. Argentina
by
Ofelia Tujchneider
Grupo de Investigaciones Geohidrológicas, Facultad de Ingeniería y Ciencias Hídricas, Universidad Nacional del Litoral, Santa Fe, Argentina
Coauthors: Marcela Pérez, Marta Paris and Mónica D´Elía

In many towns and rural areas of Santa Fe province, Argentina, groundwater is used as the main resource for regional development. At Las Colonias district, located in the centre of the province, its importance is fundamental because there is no other water source to supply the area’s requirements. The exploitating aquiferis is located in the “Puelche Formation”, which is a sedimentary sequence of fluvial origin, formed by a succession of sands with a mean thickness of about 24m. Above these sands, loess and clayey silts are developed with aquitard behavior. Lower down there are green clays and gray sands of marine origin, belonging to Paraná Formation.

For more than 30 years the aquifer has been intensively used. As a consequence of the extracted flows and the exploitation schedule the piezometric levels showed a decrease and the water quality a progressive deterioration. The increment of chlorides and sulfates in the supplying wells was generated by the vertical upward ingresión of the salt waters lodged in the lower marine formation.

The analysis of the space-temporary evolution of the hydrodynamic and hydrochemical conditions, the estimation of the recharge volumes and the formulation of the conceptual model of the system behavior have allowed to clearly identify the areas affected by the salt water intrusion. By mathematical modeling the volumes of salt water that enter into the fresh groundwater system were identified. The studies carried out up to here allowed to obtain the appropriate knowledge to elaborate a management model to protect the fresh groundwater system used as a resource. Several pumping wells were taken out of service and it was designed and implemented a new pumping field.

A monitoring network has been designed and is currently operating, with the purpose of controling at real time the behavior of the system and to prevent future affectations.

Date received: December 14, 2004

Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caod-65.