In an unusual show of power in numbers, 200 angry homeowners swamped a county hearing last night to protest plans for 30 townhouses in the swath of single-family suburbia that is Ellicott City's Centennial neighborhood.

Residents said they are worried about traffic and do not want higher density in an area where the zoning calls for roughly two houses per acre. Because the proposal is for senior housing, the developers are allowed to build five homes per acre - if they win conditional-use permission from the county.

"It's totally in conflict with the integrity of the zoning of the neighborhood," said former County Councilman Darrel E. Drown, who lives in the area and rallied the troops last night after the hearing was postponed. "What this is trying to do is increase somebody's property value at the expense of the neighborhood."

The turnout was extraordinary, even for a county where homeowners tend to look askance at development.

"I am absolutely shocked," said David A. Carney, the developer's attorney, watching the multitudes stream in.

But Centennial is no average community.

It is one of the wealthiest areas of the wealthiest county in the state - the median income is just more than $100,000 in the census tract that includes the nationally known Centennial High School - and people there are paying attention.

At the brief hearing last night, in a room too small for the throng, the county's hearing examiner postponed the case until Dec. 18 so that Howard planners can review recent changes to the plan. Then residents packed the county's Banneker Room for some Zoning 101.

Land-use discussion

Richard B. Talkin, a land-use attorney hired by several neighbors, walked everyone through the process - the possible appeals, the need to prove an "adverse affect" - and told them that county officials pay attention to crowds, despite assurances to the contrary.

"When you have this large turnout, it's an indication that [the development] is incompatible," Talkin said. "So it's important to be there."

Kimberly Homes is asking to build 30 townhouses on 6.9 acres between U.S. 40 and Frederick Road, south of the Enchanted Forest Shopping Center. Buyers would have to be at least 55 years old.

County planners recommended denying the project because they thought parking and landscaping were inadequate. A 34-foot-tall community center that would be built for the seniors exceeded height limits by 9 feet, the planners added.

County rules

Howard County lets developers build more densely if they're building for seniors because one out of three Howard residents will be eligible to move into "age restricted" homes by 2020, according to state projections. Officials do not want to lose seniors and their taxes to the Sun Belt.

A lot of builders have jumped on the bandwagon. In Howard alone, 1,700 to 2,000 units for seniors are on the drawing board, Talkin said.

Some residents were not pleased that 10 percent of the townhouses have to be priced for moderate-income buyers - "What does that mean, subsidized?" one audience member shouted. But as Talkin explained, the county's definition of moderate income is no more than about $53,000.

Patrick Crowe, who lives in the Font Hill section of Centennial and is one of the opposition leaders, said he objects to townhouses, period.

The parcel "is entirely surrounded by single-family homes," he said. "It is really an island in the middle of the sea."

Strength in numbers

After asking everyone to contribute $25 or $30 toward attorney fees, Drown issued a challenge to the community.

"You see the crowd here tonight?" he asked. "We've got to have the same crowd here Dec. 18 - or larger."