As eager shoppers flock to the recently opened Target shopping center, some city officials wonder what the site would look like if mixed-use development was more clearly defined in the city's general plan.

"There are lots of examples on the West Coast of how to do a mixed-use development and completely utilize a site," said newly appointed Planning Commissioner J.T. Wick. "The (Target) center doesn't do that. It's traditional retail — nothing else."

Obviously, not everyone agrees. The shopping center was approved by the City Council as a mixed-use development.

Councilmember Mike Harris, who voted to approve the project, pointed out that the city's general plan definition of mixed-use does not specify how much retail, housing and office space a site should have. "The Target shopping center has retail and office space, making it mixed-use by definition," he said.

Mixed-use is a term that has been bandied about in building and zoning plans for decades. For the average Petaluma resident, it dictates what types of buildings go where. It decides if that open plot of land down the road becomes a Starbucks, a home, an office building or a shopping center. For city officials, planners and staff, it's a zoning designation that requires developers to combine retail, housing or office space together. For the city overall, it decides how Petaluma will look for decades to come.

But disagreement over how it's defined has affected some of the city's biggest land-use debates in recent years, including the Target-anchored East Washington Place and Deer Creek Village shopping centers. And until its definition is put to rest, the battles are likely to continue.

Just last month, the Planning Commission denied a proposed joint Walgreens-Petaluma Health Care District venture at Lynch Creek Way on a split 4-2 vote. Though the property is currently zoned for a business park, the developer presented plans for a mixed-use commercial site — plans Wick said were not actually mixed-use.

"Obviously, the definition needs to be better explained," said Wick.

Due to what many of Petaluma's elected officials call a lack of clarity over what constitutes mixed-use, the City Council will be studying the topic at a special meeting at the end of September.

Upcoming projects that could be affected by the zoning designation include the Basin Street Properties 120-room hotel, retail and housing development adjacent to the Petaluma River, future developments in the SMART rail station area downtown and the Lynch Creek Walgreens that is set to come before the City Council on appeal later this year.

Mixed-use — defined in the Petaluma 2025 General Plan as "a robust combination of uses, including retail, residential, service commercial, and/or offices," with a focus on walkability — is not a new development term. Historically, most cities were built using the concept, combining residences with business or office space. Since few people owned cars, getting around on foot was paramount.

It wasn't until suburban layouts became the norm that separate areas of towns were designated for living, working and shopping. But as land became more scarce and concerns over climate change led to a call for less driving, planners returned to a mixed-use ideal in urban areas in the 1990s.

While most of Petaluma is zoned for residential development, a large portion of downtown and several sites along Highway 101 and Lakeville Highway are designated mixed-use. This was done in an effort to densely develop the downtown area and take advantage of its limited space.

"With the urban growth boundary, it's the most efficient use of limited land," said Duiven, who has been working on the specifics of mixed-use for Petaluma's Central Specific development plan that sets up distinct guidelines for zoning in the heart of downtown.

City Councilmember Teresa Barrett, who has long said both the Target and Deer Creek shopping centers are not truly mixed-use developments because they are retail-centric and do not promote walkability, said she looks forward to hammering out the details.

"It would be nice for the city to get some parameters around what really qualifies as mixed-use," she said. "We just have to decide what's right for Petaluma."

Barrett said that she hopes defining the term will lead to a change in attitudes about creating denser developments in the future.

"Look at the new Starbucks on East Washington Street," she said, referring to the Starbucks that opened at Wilson Street in February. "With a bigger vision, it could have had a second story of housing up there — a few apartments or condos. It could work if there was a will."

City Council members lauded the opportunity to better define mixed-use, though few could say at this point specifically what they wanted to see change.

"Mixed-use in Petaluma has taken on an "I know it when I see it" classification," said Councilmember Mike Healy. "It's become one of those things that's in the eye of the beholder."

Healy said that certain areas are more favorable for "robust" mixed-use, contending that the term should have different meanings in different parts of town.

"In the downtown core, you'd expect to see the fullest and most robust form of mixed-use, like the Theatre District," he said. "But that gets more difficult as you move away from more pedestrian-accessible parts of town."

Healy voted to approve the East Washington Place and Deer Creek shopping centers.

Meanwhile, one planning commissioner says the land designation is already well-defined. Vice Planning Commissioner Bill Wolpert, who voted against the East Washington and Deer Creek centers, said mixed-use requires more than one use and is meant to reduce car trips.

The special City Council meeting date has not been finalized, but will most likely be Sept. 30.

(Contact Janelle Wetzstein at janelle.wetzstein@arguscourier.com)