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Local geologist proposes managed recharge plan for mine discharge to benefit San Rafael Valley
Summary
John Nordstrom presented a technical proposal to the Nogales council recommending that water pumped by the South32 mine be discharged at specific ridgehead sites to restore flows to the San Rafael Valley and headwaters of the Santa Cruz River, arguing a managed approach could support ecology and carbon capture.
John Nordstrom, a local resident who described himself as a geologist, spoke to the council on Oct. 1 about an alternative approach for disposing mine discharge water. Nordstrom said he has shared a presentation with technical experts and with a U.S. Geological Survey scientist, and that the approach would place discharge at targeted ridgehead locations to direct flow into the San Rafael Valley and westward tributaries of the Santa Cruz River.
Nordstrom framed the problem as significant: he said the proposed mine pumping could discharge “6 and a half million gallons potentially per day at full production,” and that unplanned disposal could harm regional hydrology. He described a technique — building rock detention structures and distributing flows at particular hydrologic nets — that he said would allow the water to be “put back into the environment” and could provide co-benefits such as rewetting riparian areas, helping ranchers, and increasing carbon capture in restored soils.
Nordstrom said the method is informed by published USGS work and an expert, Laura Norman, who has presented on “building rock detention structures.” He asked interested residents, officials and technical staff to download his materials from a posted website, and invited further discussion: “I would like to discuss with anybody that's interested. I need your help to try to convince the forest service and the mine to do the right thing with the water.”
Nordstrom said the expected mine life is decades and that groundwater recharge from any discharged water could take centuries, underlining the long-term nature of the issue. He left contact information and requested collaboration with ranchers, federal land managers and the mine to implement an engineered discharge that would restore flows rather than simply dumping water.
No formal action followed Nordstrom's presentation. Council members and staff did not announce a next step during the meeting, though Nordstrom indicated he had shared his materials with local representatives and encouraged staff and elected officials to review his proposal.
The presentation is a technical alternative to currently-discussed disposal plans and would require coordination among the mine operator, the U.S. Forest Service, the USGS and local governments to test engineering feasibility, regulatory compliance and long-term monitoring. Nordstrom recommended stakeholders review his slide deck and contact him to pursue further study.
