What is Project Gravel?

For months, Pima County staff have been quietly evaluating a proposal to build a massive data center on 160 acres just west of Sahuarita in unincorporated Pima County.

It’s referred to as “Project Gravel” in internal county records obtained by the Tucson Agenda with a public records request.

And the big headline for us is that this proposal may never reach the Pima County Board of Supervisors for approval.

Project Gravel is, as currently proposed, an eight-building data center campus totaling roughly 1.6 million square feet, sandwiched between the Asarco's Mission Mine and residential communities west of South La Cañada Road just outside of the Sahuarita town limits. (No, this isn’t the same data center proposed for Rancho Sahuarita.)

By using some highly technical zoning rules, the data center campus proposal could be administratively approved, potentially bypassing the Pima County Board of Supervisors — and, by extension, the public.

In other words, unlike with Project Blue, you might not get a say in this fight.

Inside the hundreds of pages of public documents, Pima County staffers detail how the Idaho-based developer Sahuarita Holdings LLC wants to use zoning established in 1969 — long before data centers existed — to use the properties for industrial purposes.

On paper, two of the three parcels that are part of Project Gravel are zoned rural homestead — which allows for, among other things, off-grid residential homes.

But a deep dive into the documents reveals repeated references to a previous zoning case for the same parcels dating back to 1969, when the Barney Kerley Company acquired a portion of the former Roadrunner Ranch to build a chemical plant to produce mineral lime for the nearby mines.

The purchase of the former ranch in 1969 prompted the company to submit a zoning request to convert hundreds of acres then owned by the Barney Kerley Company for industrial purposes.

County records suggest the company quickly completed the rezoning requirements for roughly 10 acres that were used for the plant, which ran from the 1970s until it closed in 2006.

The rest of the property has defaulted back to rural homestead zoning.

But if Sahuarita Holdings successfully satisfies the requirements of that 1969 deal, it could get the green light from the county’s Development Services Department to build the data centers.

The industrial zoning aspect is important, as the project could then potentially bypass the Pima County Board of Supervisors entirely.

Project Blue went before the supervisors last year not only because of a rezoning, but because the agreement with developer Beale Infrastructure included the sale of the county-owned, 290-acre parcel to a subsidiary of the developer.

This time around, there is no county-owned land involved with Project Gravel, and the property doesn’t need to be rezoned.

But plans for Project Gravel may still have one Achilles’ heel that will send them to the supervisors for a vote.

The documents we reviewed tied to Project Gravel show that the company is still working out some of the details, including plans for an electric substation on the property that would be operated by the Trico Electric Cooperative.

The company said the substation would improve electric service in the area, but it would still require approval from the Arizona Corporation Commission — and the Pima County Board of Supervisors.

The law requires that the board hold a public hearing and vote on the substation, but we’re not clear whether it has the discretion to reject it if it meets the minimum criteria established by county code.

So the supervisors may get a vote on the substation — just not necessarily the data center campus surrounding it. But no substation likely means no data center.

The Project Gravel plans were also flagged by the Regional Flood Control District, which rejected the proposed drainage strategy for the data center campus.

Staff wrote that the district is “not supportive of the current site design as shown” and rejected it partly because the proposed retention basin and a lined runoff channel are too small.

But this could be less of a roadblock and more of a hurdle, as the company can submit new designs as part of its application.

None of the documents we reviewed state how much water or energy the data centers — which the company hopes to be fully operational by 2029 — will use each day.

Pima County Supervisor Jennifer Allen, whose sprawling, mostly rural district includes the proposed data center, said she would be the first “no” vote if it did reach the supervisors for approval.

Allen has been frustrated with Project Gravel, in part because of a nondisclosure agreement (NDA) signed last year by the county’s procurement department.

In the past, Allen has said she does not believe that the county should enter into NDAs and is unafraid of potential legal challenges that might come from saying no to a development.

A 2006 voter-approved measure known as Proposition 207 allows people and companies to sue if they feel new local laws hurt the value of their property, which the data center could lean on if supervisors reject its plan. But the law has a carve-out for laws enacted to protect public health and safety, meaning if supervisors could hinge their arguments against the data center on public health, they may be able to legally stop it.

So will the county sign off on a 57-year-old plan? That’s too early to tell.

For what it is worth, the supervisors were asked back in January to approve zoning established in 1970 for a proposed apartment complex along Valencia Road.

So there is a recent, similar precedent.

Meanwhile, the county will consider a 120-day moratorium on data centers tomorrow, while the Tucson City Council considers a new ordinance for large water users that was born out of the Project Blue controversy.

It’s unclear whether the moratorium would prevent the county’s Development Services Department from continuing to evaluate the Project Gravel proposal or if the moratorium would simply restrict county officials from approving any data center-related permits or plats.

That distinction could determine whether Project Gravel keeps moving forward while the moratorium is in place.

The county also created a new policy for nondisclosure agreements, again as a reaction to the Project Blue kerfuffle.

Nationwide, cities and counties are taking aim at data centers.

For example, Ohio has 138 separate moratoriums on data centers covering various cities and towns.

County officials have told us that there are only two data centers being discussed at any level of county government right now — Project Blue and Project Gravel.

When asked the same question, Tucson officials said they are not talking to any data center companies.

We’re aware of at least two data centers being proposed in Marana and another being discussed inside the Sahuarita town limits.

Put it all together, and Southern Arizona’s data center debate is no longer about a single controversial project.

But then again, maybe the recent call from various major AI companies to slow things down will trickle back to Southern Arizona.