Testing measures are changing for how Gallup dumps treated wastewater into the Rio Puerco.

The city’s agreement with the New Mexico Environmental Department to dump up to 1.25 million gallons of wastewater every day into the local tributary was altered to eliminate certain water tests if Gallup meets chemical standards. It also requires the city to cap three wastewater wells and build a new one to meet groundwater monitoring guidelines.

The settlement between Gallup and the state’s environmental department was unanimously approved Tuesday by the New Mexico Water Quality Control Commission and helps avoid a contentious legal battle.

“We entered into a settlement agreement to provide alternative methods,” said Jason Herman, program manager at the state’s Ground Water Quality Bureau.

The Gallup Wastewater Treatment Facility receives and treats 3.5 million gallons of wastewater per day. The city is permitted by the state to discharge over a third of that – 1.25 million gallons – into the Rio Puerco every day.

When the New Mexico Environment Department published revisions to that practice in May 2022, the state issued the changes in August 2022 despite objections by officials in Gallup.

So the city took the matter to the Water Quality Control Commission. Gallup asked the agency in September 2022 to review the permit with concerns that standards that required well plugging and testing standards would take up unnecessary time and resources.

This led to a monthslong review of the permit. Gallup and the New Mexico Environment Department eventually agreed not to enter an even lengthier legal process and committed instead in January 2023 to come to a settlement.

The agreement was finalized in March. It supersedes the revised 2022 permit issued by the state.

N.M. Environment Department spokesperson Matthew Maez said via email the agreement benefits both parties.

“It specifies the actions that Gallup must perform to meet the requirements of the permit, avoiding a protracted legal dispute, while protecting groundwater and public health,” Maez said.

Herman testified at the Water Quality Control Commission meeting on Tuesday and said the agreement addresses two main issues the city had.

The first update changes a clause that required quarterly tests for arsenic. The city could’ve asked to stop testing if arsenic levels were low enough after four consecutive samples.

Gallup then argued that arsenic isn’t present in the facility’s wastewater and having to regularly test for it would “be costly and burdensome.”

The settlement amends this section so Gallup can ask to stop testing if two – instead of four – consecutive samples contain minimal amounts of dissolved arsenic.

The other change has to do with replacing monitoring wells that analyze groundwater. The 2022 permit required that Gallup plug, abandon and replace three wells that the state said were constructed improperly.

Gallup said replacing the working wells would waste time and resources.

Under the new agreement, the city still has to abandon those three wells. Gallup would also have to install a new well, testing it to ensure that it follows state health and safety standards.

Maez said the well installation will help the city “better understand the local geology” and figure out if operations at the Gallup Wastewater Treatment Plant have impacted groundwater.

Gallup also told the Water Quality Control Commission last year that construction renovations would be difficult, if not impossible, to meet due to supply chain constraints. Maez said if that’s still an issue, the Environment Department can extend deadlines.

The state’s water commissioners did not have many questions about the agreement or any objections. Robert Sanchez, who helps counsel the commission, said it’s a pretty clear settlement.

“I think they know what they need to do to stipulate the settlement agreement,” he said.