Cochise County's only source aquifer keeps three communities flowing with water

NACO, Ariz. (KGUN) — Water conservation efforts in Cochise County tends to focus on the San Pedro River and recharging the river, but in Naco, the Naco Sanitary District board members have concerns about saving the sole source aquifer.

“Everybody’s been ignoring this aquifer,” said Naco Sanitary District board chair, Stephen Dey.

The Naco-Bisbee aquifer provides water for Naco, Arizona; Naco, Sonora, Mexico; and Bisbee. Dey said their four wastewater lagoons hold 86,000 gallons of effluent water.

“If we keep an eye on it and do proper development, we could maintain control of this probably this aquifer stability for, I would have to say indefinitely,” he said.

While there's more than enough water for human consumption, Dey said there's still concern for the water supply. The threat to the groundwater is from a sulfate plume that is moving from south of the Warren District towards the well the City of Bisbee uses for its water. The sulfate contamination is from the past when the mines were still active in Bisbee.

“It’s a completely stable aquifer except for the sulfate plume. That’s the only threat," Dey said. "50% of the wells in this aquifer are contaminated to the point of not being able to be used because of the sulfate.”

This doesn't have to be an unsolvable problem. Charles Behney, vice chair of the Naco Sanitary District, said this problem can be fixed by either stopping the pumping the water or by back pumping the contaminated water and treating it before putting it in a treatment pond.

“We need to clean the sulfate plume and ensure water adequacy for the next 100 years,” he said.

The City of Bisbee has some of its treated effluent being released on The Naco Sanitary District's property. Dey said if the water was treated a bit more than it currently is then it would be beneficial to the aquifer as it could recharge the aquifer with less pollutants in the water.

The City of Bisbee is moving some of their effluent, with the Bisbee Effluent project. The city partnered with Cochise County to help recharge the San Pedro River.

“It’s 12 miles from here to the river," said Environmental Projects Coordinator for Cochise County, Mark Apel. "The intent is really to take as much of that water as we can and recharge it as close to the Mexican border and to the river as possible.”

The project is still in its planning phase, but will have pipeline run through the community of Naco to the border where it will release treated effluent close to the river. Apel says this speeds up the natural process that could take 100 years for water to move the 12 miles or because of evaporation it may never get there.

“It’s sort of short cutting the root the water would normally take through the ground," he said. "While there may be plenty of water under our feet, the river depends on the first 10, 20, 30 feet.”

Bisbee mayor Ken Budge, also the chairman of the Upper San Pedro Partnership, said the San Pedro River has been studied for 25 years. He sees opportunities to continue to help the river which is what the partnership happened in 2019 between the City of Bisbee and the county.

“It’s just another part of working in sections along the river to make it more and more viable,” Budge said.

Dey and Behney said this project could be a threat to the sole source aquifer because the water is being taken and placed in another location.

“We don’t want our aquifer’s water to be used in any of those two aquifers," Dey said. "Until such a time that they show us maybe they got a little bit more responsible use for their water.”