WALNUT CREEK -- At 25 acres, it's the size of the city's traditional downtown, but half of the lot at the corner of Ygnacio Valley and Oak Grove roads is untouched, a home to ground squirrels and oak trees -- not a norm for this city.

Which is why a mixed development complete with a Safeway-anchored shopping center, senior housing, amphitheater, park and four acres of open space in eastern Walnut Creek has taken nearly three years to plan.

On Tuesday, the project, with vocal supporters and opponents, will go to the City Council for a final decision at 7 p.m. at City Hall, 1666 N. Main St. If the council approves, construction of the 195,000-square-foot shopping center would likely start this year.

Safeway-operated Property Development Centers has been pushing for years to develop the property, which is currently home to some of the grocery giant's corporate offices at the entrance to the Shadelands Business Park. The proposal, dubbed The Orchards, includes a health club, roof-top parking, restaurants, outdoor open plazas, retail shops, a splash area for children, outdoor dining, a community room and a one-mile meandering trail through the development.

"We feel like we have developed this plan with all the community involvement that we were able to muster," said Deb Karbo, of Property Development Centers, at a Planning Commission meeting May 22.

The mixed-use center is expected to generate $82.7 million a year in sales, according to an urban decay study done on the proposed development.

The plan has garnered more than 300 comments for the environmental review, and while some residents say it's time the area had more restaurants, a bigger Safeway, open space and park for children, others have been against it from the beginning.

Concerns range from added traffic and the loss of trees to the effect the new development will have on surrounding centers; specifically, with a new Whole Foods coming to the current Safeway site on Ygnacio, many fear it spells doom for the older Nob Hill nearby. Opponents claim that Walnut Creek has created a windfall for Safeway.

"It's totally overkill and will not serve our neighborhood; our neighborhood is served by the present establishments that are there," resident Brad Rose said at the meeting.

But supporters say the focus should be on how much the neighborhood will benefit, specifically children with a water park, playground and performance areas.

"I think it's a very exciting and vibrant project for our side of town," said resident Kim Harris. "To me, this is really not a strip mall; it's something much more than a strip mall, and I don't get the sense that people are focused on that."

The plan calls for the removal of 199 trees -- 30 highly protected trees -- and developers say they will re-plant 614 trees. The city's arborist has approved all but 46 of the trees to be removed.

That leaves it up to the City Council to determine that the tree removal is necessary. This is a particular sticking point with some residents who point to the city's recent battle to preserve trees that Pacific Gas & Electric wants to take down.

"The city ought to adopt the same forceful response it has taken with PG&E," said Steve Elster, who lives nearby and has followed the project from the beginning. "If the city does ultimately acquiesce to Safeway's tree-removal plan, that will set a terrible precedent for the city's future consideration of PG&E's tree-removal plan and all other tree-removal plans."

Elster and others have recently formed "Friends of Walnut Creek," which he says will represent "our concerns about Safeway's development and the city's noncompliance with the California Environmental Quality Act."

He argues that there are reasonable alternatives, such as not including a supermarket in the project or having Safeway develop the western half of the property and leave the eastern half as open space.

Neither option is endorsed by Safeway, and developers have constantly reminded the public that this is private property and not city-owned open space.

If approved, this could mean retail and housing in a business park that has never seen these uses. Real estate reports show that shopping centers in Walnut Creek are at 98 percent capacity -- which is basically unheard of in North America, said John Cumbelich, a Walnut Creek real estate broker.

"That is statistically next to impossible, and what that does mean is there is way more demand than there is supply," he said.

The project started well before the announcement in March that private equity firm Cerberus Capital Management, which owns the Albertson's chain, will purchase Safeway for $9 billion. Some in the community have argued that it's premature to approve a plan when Safeway may shutter stores. But there is already a pre-agreement with Cerberus for this site, Karbo said.

"PDC owns this property, so when Cerberus does buy Safeway, and if it buys Safeway, Cerberus would be our tenant," Karbo said. "It's not like they can come in and decide they don't want this store."

How far residents opposed to the project are willing to go is unclear. Elster says "Friends of Walnut Creek" does not know whether it will take its arguments all the way to court if the project is approved, but the group is looking for an attorney.

Contact Elisabeth Nardi at 925-952-2617. Follow her at Twitter.com/enardi10.

If you go
What: Walnut Creek City Council meeting
When: 7 p.m. Tuesday
Where: City Hall, 1666 N. Main St.