Somewhere near the water tower perched at the end of a line of palm trees along Highway 99 between Manteca and Ripon is where a major interchange key to growth for the next 30 years in both cities is expected to be built.

It also will serve as the main access to the biggest development ever proposed in Manteca - the 1,037-acre Austin Road Business Park envisioned to generate 13,000 jobs and provide housing for 10,200 people.

How the interchange will be funded and exactly where it will be built are two questions that elected leaders in Manteca and Ripon will need to answer.

 The answer to where the interchange will go is expected to be provided in an $111,109 study the Manteca City Council is expected to commission when they meet Tuesday at 7 p.m. at the Civic Center, 1001 W. Center St.

Manteca staff along with representatives from Ripon, the San Joaquin Council of Governments and Caltrans are recommending the hiring of Mark Thomas & Co. to perform a project study report.

The consultant - working with staff from both cities - will develop a plan to connect future road networks in Ripon and Manteca. After that, an assessment of future traffic needs will be done based on approved land uses. Then the work will be submitted to Caltrans for approval.

Once Caltrans approves the interchange location, the next step would be environmental studies along with an analysis of alternatives.

 The alignment of roads could have a significant impact on existing residents as future development occurs. One such future road is how the alignment of McKinley Avenue will go as it is taken south of Woodward Avenue and swang eastward toward the new interchange.

Manteca and Ripon originally had each planned on building their own interchanges between the existing Austin Road interchange and the Jack Tone Road interchange with a mile separation from existing interchanges. Ripon’s was planned for Olive Avenue while Manteca’s was roughly a mile south of the 120 Bypass and was known as the “new” Austin Road interchange.

Earlier this year, Caltrans informed the two cities that state standards now require a two-mile separation between interchanges if one of them is between two freeways such as at the 120 Bypass and Highway 99. That meant Manteca and Ripon had to alter their existing development plans and feed future road systems into one major interchange.

The new interchange is essential for the complete build out of the 1,037-acre Austin Road Business Park that will straddle Austin Road south of the existing Highway 99 interchange and borders the railroad and freeway on the east. Manteca has already approved the project.

The first phase will consist of the employment center. It can start development without a new interchange although modifications will be needed to the existing Austin Road interchange.

Those improvements run the gamut from ramp improvements to traffic signals.

Austin Road Business Park includes:

• 3.5 million square feet of general commercial or about 26 times the square footage of the Manteca Costco store.

• At least 2,358 traditional single family homes and 1,840 multi-family dwelling units such as townhouses, apartments, and condos  that can accommodate up to 10,200 people or just under a seventh of the city’s existing population.

• 8 million square feet of industrial/business park, and office use or space equal to 17 times the coverage area of the Ford Motor Parts distribution center on Spreckels Avenue,

• A 5,000-seat amphitheater plus Manteca Convention & Visitors Bureau events center.

• The potential to create up to 13,000 jobs - or close to 50 percent of the existing jobs in the city - with between 3,000 and 6,000 jobs coming from the industrial and business park portion and up to 7,000 jobs from possible retail uses.

• Five parks with just over 49 acres compared to the nearby 52-acre Woodard Community Park.

• The potential for school-age children who will live in homes that are within the Manteca city limits to attend school at Ripon Unified School District campuses. Some 849 acres of the project are in the boundaries of the Ripon Unified School District while 202 acres are within Manteca Unified School District boundaries.

• Eighty-four acres that are zoned for mixed commercial and retail uses which means it could involve condos above stores or large condo, apartment, or townhouse projects interwoven with commercial uses.

• Zoning for up to 1,840 units of apartments or other high residential uses including 828 units possible in the mixed commercial zoning depending up how that ends up panning put. That’s about 1,500 less than all existing apartments now in place in Manteca.