Evaluation of the feasibility of a managed aquifer recharge through irrigation canals in the Lower Diguillín River basin, Chile

Author: Luis Alegria

Alegria, Luis, 2022 Evaluation of the feasibility of a managed aquifer recharge through irrigation canals in the Lower Diguillín River basin, Chile, Flinders University, College of Science and Engineering

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Abstract

One of the many sustainable management practices of water resources is the so-called managed aquifer recharge (MAR) method. This technique, apart from injecting water into the system, includes a variety of short-term and long-term benefits for the community. Globally, a series of real case studies have been carried out to evaluate the efficiency of MAR techniques, however in Chile it is still relatively unknown to ordinary people. An efficient MAR design consists of maximizing the storage gain with the least amount of injected water and minimize the losses through downstream discharge. Within the methodologies to develop a MAR, there is the recharge through irrigation canals, where Chile comes to play a fundamental role due to its extensive portfolio of unlined canals for agricultural purposes. In this study, different MAR designs were examined using the irrigation canals at the Lower Diguillín River Basin (LDRB) located at Southcentral Chile, through the construction of a numerical model using Flopy (MODFLOW) and the processing of water balance outcomes of the shallow aquifer for each established scenario, with the objective of defining the most efficient MAR design for the LDRB. As a result, it is obtained that the maximum annual volume of an efficient recharge lies between 5x105 m3 and 9x105 m3, which represents around 2.5% and 11.2% of the total annual inflows for the same period.

Keywords: Managed aquifer recharge (MAR), Diguillín (Chile), Irrigation Canals, Efficiency, Flopy

Subject: Hydrology thesis

Thesis type: Masters
Completed: 2022
School: College of Science and Engineering
Supervisor: Okke Batelaan