Cathy Wiss, coordinator of the water quality monitoring program at the Audubon Naturalist Society, collected samples in Ten Mile Creek this past summer in Clarksburg, Md. She and others are advocating for the full preservation of the Ten Mile Creek watershed. (Katherine Frey/The Washington Post)

The Montgomery County Planning Board, trying to strike a balance between growth and environmental protection, has approved revisions to the blueprint for Clarksburg, including safeguards for the Ten Mile Creek watershed and provisions for 600 new single-family homes near Inter­state 270.

The board’s actions late Thursday are a new chapter in an ongoing debate over how to best fulfill the original 1994 concept for the northern Montgomery community, which envisioned a green, walkable urban village at its heart. Board members and Montgomery officials said the amendments are an effort to protect one of the most environmentally sensitive areas of the county while aiding Clarksburg’s maturation as a community with more opportunities for jobs, transit and a mix of housing.

“It’s a balance of a lot of very important public policies,” said Planning Director Gwen Wright.

But the panel’s decisions left fierce advocates on both sides dissatisfied. It sets the stage for another bruising debate between real estate and environmental interests when the plan reaches the Montgomery County Council for final action early next year.

“We’ll find out whether the council represents the citizens of Montgomery County or developer interests,” said Caroline Taylor, executive director of the Montgomery Countryside Alliance, a group that promotes protection of the 93,000-acre Agricultural Reserve, which borders the Clarksburg area.

“Now we go to the council,” said Gus Bauman, attorney for Pulte Homes, which had plans for 1,000 single-family homes on 538 acres west of I-270 between Shiloh Church and Clarksburg roads. In July, county planning staff members recommended sharp restrictions on construction, limiting the project to about 200 homes and setting aside most of the site for open space.

The board decided to allow about 600 new homes and reduced the percentage of land dedicated to open space from 80 percent to 65 percent. But it also rezoned the Pulte property to require that the homes be clustered together more tightly on smaller lots to shrink the project’s blueprint.

Pulte is expected to press the council to restore the original zoning. In anticipation of building on a bigger scale, the company spent $12 million to purchase development rights from landowners in the Agricultural Reserve. The transaction was made under a program designed to preserve land for farming while allowing for more construction in selected areas.

The board called for fewer changes to another major development proposed east of I-270, where the Peterson Companies is planning 450,000 square feet of retail dining and housing on about 100 acres. The board adopted the staff’s recommendation to tighten the impervious-surface cap from 33 percent to 25 percent of the project’s footprint to limit storm runoff.

The Peterson development, called Streamside, would be near the site for the long-delayed Clarksburg Town Center, which was to have as its centerpiece neighborhood retail and civic space to anchor village life. Plans by the original developer, Newland Communities, collapsed amid a sour economy and violations of county regulations. A new developer, Elm Street, is revising the plans.

Officials hope Streamside will catalyze creation of Town Center. “Having some additional development at appropriate scale near Town Center will energize Town Center,” Wright said.

Officials say the new construction also will increase Clarksburg’s chances of connecting to a proposed mass transit system that will evolve over the next few years — either the bus rapid-transit network or the Corridor Cities Transitway on I-270.

Last fall, the County Council asked the board to reexamine the 1994 Clarksburg Master Plan after studies showed that water quality in the Ten Mile Creek watershed had suffered and would continue to deteriorate if construction went forward as envisioned in the original blueprint.

The board approved establishment of a special zone imposing a 25 percent impervious-surface limit near Town Center, 10 percent west of I-270 and an average of 8 percent across the watershed. Planners cite consultants’ studies concluding that water quality in Little Seneca Reservoir will not be significantly damaged.

But environmentalists expressed disappointment Thursday at the board’s efforts to protect Ten Mile Creek, one of the county’s last streams with good water quality. It also is a source for Little Seneca.

“I’m not happy,” said Diane Cameron, director of conservation at the Audubon Naturalist Society. “They think 8 percent will protect Ten Mile Creek. It won’t. It will devastate Ten Mile Creek.”