Pima County finally reached an agreement with Kinder Morgan to mitigate any long-term environmental damage caused by the 60-mile pipeline the company wants to build from Tucson to Sasabe.

Kinder Morgan will monitor the pipeline and surrounding area for 20 years and give the county $4 million to offset environmental degradation and mitigate the loss of any riparian habitat in the Altar Valley, where the company’s Sierrita pipeline will carry natural gas to Mexico.

The county Board of Supervisors approved the mitigation measure unanimously Tuesday, although some members were reluctant.

“I don’t have a lot of faith in all of this coming to fruition,” said Supervisor Richard Elías. “I don’t feel too good about this.”

The agreement calls for Kinder Morgan to pay a lump sum, in-lieu fee of $3 million for riparian losses in the area and to give another $1 million so the county could buy land to offset degradation to the area near the pipeline and minimize any adverse long-term impacts.

Kinder Morgan will also have to document revegetation and topography, monitor erosion in washes and elsewhere along the corridor, and monitor the impacts of illegal trafficking and drug smuggling in the area.

In addition, the company agreed to a request by the Tohono O’odham Nation to pay for an archaeologist to check the area every two years to monitor cultural resources.

The agreement ended months of opposition, threats of legal action and negotiations between the county, Kinder Morgan, Altar Valley ranchers and other groups.

County officials joined with ranchers, the Tohono O’odham Nation and other groups to vociferously oppose the pipeline, saying it would further damage pristine land in the area while potentially creating a new smuggling corridor.

All of the groups were skeptical of Kinder Morgan’s proposal to replant native plants along the pipeline, saying the company’s efforts to revegetate areas near its other pipelines were inadequate.

County Administrator Chuck Huckelberry previously said the pipeline could hurt county taxpayers, who could pay $16 million in the first year of the pipeline’s operation for increased Sheriff’s Department patrols, access-road maintenance and other costs.

In the end, there wasn’t much the supervisors could do to stop the pipeline, which is awaiting final approval from the Federal Energy Regulatory Commission.

The project could receive that approval this month.

In March, the commission released a final environmental impact statement which found construction and operation of the pipeline would result in limited adverse environmental impact.

Last month, the U.S. Fish and Wildlife Service issued a draft compatibility determination, saying it was permissible for Kinder Morgan to use 12 miles of roads in the Buenos Aires National Wildlife Refuge during construction of the project.

Fish and Wildlife officials expect to release a finalized version of the report within the next few weeks.

The county originally sought $12 million from Kinder Morgan to mitigate damages and pay for law enforcement, destroyed habitat area and annual costs.

But the county lowered the amount when the company agreed to manage the area for 20 years.

Earlier this month, Kinder Morgan also agreed to give the Altar Valley Conservation Alliance $1 million to use for conservation work in the area.

In exchange, the conservation alliance agreed to withdraw its opposition.

Contact reporter Jamar Younger at jyounger@azstarnet.com or 573-4242. On Twitter @JamarYounger