UNAM presents management proposal for Sonora river basin

Tuesday, April 17, 2012

Researchers at Mexico's national autonomous university UNAM have presented a project to water authority Conagua that aims to address the overuse of aquifers in the Sonora river basin, Fernando González, a researcher at UNAM's engineering department, told BNamericas.

The project adopts an integrated approach to the management of water resources in the river basin through placing restrictions on agricultural and human consumption, harvesting and infiltrating rainwater and reinjecting treated water into lagoons.

"Given the rising demand in the basin, it's important to consider reuse in water management initiatives," said González.

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Agricultural use currently accounts for some 42Mm3/y of water in the basin, while human consumption in state capital Hermosillo reached 102Mm3 in 2010.

Proposals for the upper part of the basin include works to enhance natural filtration capacities along the river as well as extracting water from existing dams to store in the aquifer. Storing extracted water will reduce evaporation, helping the region to withstand years of drought, said González.

"In the lower part of the basin, we plan to inject treated wastewater into infiltration lagoons to recharge the aquifer," he added.

González estimates that reducing overuse of the aquifer by 70% and agricultural use in one part of the basin by 30% would result in an 80% reduction in aquifer overexploitation.

The initiative will be significantly cheaper than the proposed Caracol reinjection project in Mexico state (Edomex), as the treated wastewater will not be injected into wells, which means it will need a lower level of treatment, according to the academic.

"We should be pursuing this type of project as opposed to those that require enormous investments and cause conflict," González said, in reference to Sonora's Independencia pipeline project, which has met with opposition from farmers in the Yaqui valley.

Gonzalez expects Conagua and the Sonora river basin management committee to evaluate the project over the coming months.