Developers want to build as many as 5,000 homes at the western end of Valencia Road, near Ryan Air Field. They also are planning two major commercial centers, and as many as 10,000 more homes, which could follow in their wake over the next two decades.

And then there is another development, north of Duval Mine Road, near Sahuarita, that has now become a lightning rod for community concern as Pima County’s Planning Division reviews its west side comprehensive plan.

One thing all sides seem to generally agree on is that the area near Ryan Airfield should be opened up to intensive development, making it the home for as many as 40,000 future residents. On top of that, developers would like the county to allow them to push further out into areas that had been considered too sensitive for residential construction.

At a public meeting Sept. 5, Ben Changkakoti, principal planner for the Planning Division, said the plan is to try to figure out what the 81-square-miles of land on the southwest side will look like in 20 to 30 years and to plan the infrastructure to meet what demands will come.

Over the next decade developers are planning three master-planned communities along Ajo Way near Valencia Road.

Pomegranate Development is looking to build as many as 1,900 homes and a retail-office center on 738 acres, a half-mile east of Ryan Airfield, according to principal Kevin Tomkiel. Montecito Communities, based in Las Vegas, wants to build as many as 2,500 homes along with another commercial center on 837 acres immediately to the west of the Pomegranate site. And the Economic Development Authority of the Tohono O’odham Nation is planning to build another 325 to 340 homes.

None of those are controversial, said Changkakoti, because the county has already done studies projecting 20,000 to 40,000 people in the area by 2020.

But another project is becoming controversial. The Mission Peaks development on 4,200 acres on the west side of Interstate 19, between Helmet Peak and Duval Mine roads, is in an area known for rare species and 37 sites of archaeological significance.

Project spokesman Mike Grassinger, chief executive officer of The Planning Center, said 1,200 acres at Mission Peaks site will be preserved. Another 2,200 additional acres that were formerly off-limits, will be developed, through a $13 million mitigation agreement with Pima County, trading acreage inside the project for acreage elsewhere.

But John Leonette, a Sahuarita resident, called it a bad deal, saying the $6,000 per-acre that was paid is far below the purchase price of similar land in the area. Another neighbor, Stanley Stokes, said 27 of the 37 historic sites will be destroyed, with artifacts removed to Arizona State Museum.

The Planning Division’s Changkakoti amendments to the comprehensive plan are still being researched and compiled and should be ready to go to the Planning and Zoning Commission Oct. 31 and then on the Board of Supervisors in December.