RIVER FALLS, Wis. — This college town that sits on the pristine Kinnickinnic River less than 30 miles from downtown St. Paul is at the epicenter of the current wave of development in western Wisconsin.

In less than a year, more than 800 acres of adjacent township land have been annexed by the city to build nearly 2,000 homes, and developers are eager to annex more. As the community, which straddles the line between St. Croix and Pierce counties, continues to grow, major retailers also are calling.

If all the homes are built, the city will grow by as many as 6,000 people, raising the population by almost 50 percent. The pending boom has critics of the three annexations calling the city "River Sprawls."

Even those who haven't taken sides are wondering whether the development light needs to be changed, if not from green to red, at least to flashing yellow.

But most city officials say they are ready for the growth.

"We had an idea this would occur and have been working on smart growth plans," said Mariano "Buddy" Lucero, city planning director.

He said the city is seeking to keep its small town atmosphere and help, not harm, its Main Street business district.

That is a main reason that Hans Hagen, CEO of a Minnesota development company, said he and others want to build there and so many want to buy.

Hagen plans to build about 500 homes ranging in price from $150,000 to $350,000 on a 236-acre tract adjacent to the Kinnickinnic River and on the northeast boundary of River Falls.

"It's a small town with a downtown. It has a college, excellent schools and good infrastructure," Hagen said. "And the transportation — it's freeway all the way. Plus, the land — it's a pretty part of the country. These are all things that make it very attractive."

Of the three recent annexations, Hagen's Wild Flower is the most controversial because of its location along the Class 1 trout stream.

"This stretch has the highest concentration of trout along the river," said Rick McMonagle, of the Kinnickinnic River Land Trust. "The impact will be devastating."

River Falls is the only city on the river and while the effluent discharged into the river from the sewage treatment plant meets state standards, McMonagle said, those standards don't include household cleaning products and pharmaceuticals.

"Which will end up in the river," he said, "Plus the runoff from all those driveways, lawns and the road. It's a flat valley there with direct access to the river by all those people."

Hagen said preserving the river is crucial. And he'd prefer to hook into city services, including sewer, rather than rely on septic tanks and drainage fields.

The pace of development seems to be quickening. While another developer was seeking permission from the city last Tuesday to annex more land, the Kinnickinnic Township Board voted to sue River Falls for approving the Hagen annexation last month.

This Tuesday, as a 120-day moratorium on retail development of stores bigger than 30,000 square feet expires, the River Falls City Council will discuss new ordinances for big box developments. Currently, the largest retailer in River Falls is Shopko, which has about 83,000 square feet.

Tom Parent, one of two council members who voted against the Hagen annexation, said the council ignored the Wisconsin Department of Administration's opposition to the annexation.

He is also concerned that the city risks being seen as a bad neighbor and angering the four adjoining townships, including Kinnickinnic, by ignoring a comprehensive sewer district plan.

"We agreed to annex no more than 60 acres a year and we now annexed more than 800 in the last nine months," Parent said. "We've had 20 years of growth before our 20-year plan is complete.

"There are people who say growth is inevitable, that we have no control. In reality, we do, but we must exercise it. The city must decide. Not developers."

Chris Kusilek, a local developer, disagrees with critics he believes are in the vocal minority.

"I feel the council members have been doing a good job for the city. They've been planning for year. To say they haven't is an insult," said Kusilek, who along with Mark Sylla, is developing two phases of the Boulder Ridge Development.

River Falls Mayor Eric Amundsen vetoed the council's initial approval of the Hagen annexation. The council overrode the veto — which Amundsen had tried to rescind in a show of unity — again by a 5-2 vote.

"It's important to work as a team, so I support the council," the mayor said, but added after approving three annexations, "it's time to slow down and catch our breath. I'm not anti-growth, but growth management is important."