The Montgomery County Council brought a formal end Tuesday to the Battle of Ten Mile Creek, unanimously approving sharp limits on construction in the environmentally fragile watershed around Clarksburg.

The issue was effectively closed after a 9-0 straw vote the council took on March 4. Tuesday’s final action brought another round of council member speeches, but no last-minute twists in substance.

The council amended Clarksburg’s 1994 long-term land-use plan, following months of testimony and reams of data from environmental scientists, activists and real estate interests with plans for the northern Montgomery suburb off of I-270.

The council ultimately concluded that polluted storm runoff from major new development imperiled the health of Ten Mile — one of the county’s last clean, biologically robust streams. It is one of several that empty into Little Seneca Reservoir, part of the Washington region’s emergency water supply.

The master plan amendment thwarted efforts by the Peterson Companies to build a retail and hotel project on 100 acres east of Interstate 270, near the site of the planned Clarksburg Town Center. Company officials, who have an option to purchase the land, have indicated that they will likely walk away from the project. Pulte Homes, which sought approval for about 800 single-family houses and townhouses on 538 acres west of the interstate, would be trimmed back to about 500 homes under the plan. Company officials have vehemently protested the new limits.

The council’s review of Clarksburg was built into the 1994 master plan, which called for a pause in construction to evaluate environmental impact. For more than a year, the Montgomery Planning Board and the council have wrestled with the issue, hearing threats of lawsuits from developers and ultimatums from environmental groups that their decision represented an election-year litmus test.

The outcome has already produced political fallout. A group of developers is seeking to oust Council member Roger Berliner (D-Potomac-Bethesda), a key player in drafting the final version of the master plan amendment. Bruce Lee, president of Lee Development Group, Kevin Maloney, former chair of the Bethesda-Chevy Chase Chamber of Commerce, Brian Lang, senior vice president of Guardian Realty Investors and Jim Soltesz, whose engineering firm worked with Peterson in Clarksburg, are backing Berliner’s challenger, former at-large council member Duchy Trachtenberg.

On Tuesday, Berliner reaffirmed his position.

“This is a proud moment for our council,” he said before the final vote. “We have reflected on the evidence, scientific and otherwise, and the evidence was overwhelming. The environmental experts all said essentially the same thing – this watershed is a treasure, it is fragile, and that even the little amount of development that has taken place in the headwaters has already harmed it.”

Directly addressing opponents in the developer community, Berliner said: “And while we have taken the issue of property rights seriously, we have not catered to the interests of sophisticated commercial interests. ...We have, by our actions, declared that all development is not equal. Where development is in the overall public interest – where we can harmonize our land use and environmental objectives – our council has supported additional development, especially in areas served by transit. But the fact that Ten Mile Creek was not one of those places does not transform our decision into one of political expediency as some have claimed. Just the opposite.”

Council President Craig Rice (D-Upcounty), who represents Clarksburg and supported the Peterson project, issued what amounted to an apology to constituents. He said he entered office four years ago with a promise “to make things right,” which meant he would make sure residents received amenities that the town had gone without.

Other council members were persuaded by a retail consultant’s report that the best site for retail was a location on the west side of I-270 and that the Peterson plan would actually impede the development of Clarksburg Town Center. Rice said he would continue to try to fulfill his promise.

“I will continue to work with Clarksburg,” he said.