As a prominent real estate firm in the region, the Peterson Cos., has become deeply versed in developing profitable housing, office buildings and shopping projects and — with National Harbor — hotels and maybe a casino.

But as the company advances a plan to build a Tanger Outlets shopping center at Ten Mile Creek in Clarksburg, the company is becoming more versed in the intricacies of beavers, waterfowl, mayflies and natural springs.

Led by longtime patriarch Milton V. Peterson, Fairfax-based Peterson Cos. is pushing Montgomery County to amend its master plan for Clarksburg to allow the construction of “Streamside at Clarksburg” on 100 acres near Ten Mile Creek.

The master plan was created in 1994 as a way of guiding Clarksburg’s development from a rural crossroads. Since then, the community has evolved into more of a suburban community — one waiting on amenities promised by the still-unfinished Clarksburg Town Center.

At a forum held by the county planning board last week, residents of the area raised concerns that allowing construction of a shopping center in the headwaters of Ten Mile Creek would not only create new competition jeopardizing the 270-acre town center project, but generate the kind of storm water runoff that would harm the cleanliness of the creek and health of its wildlife.

Staff from the Audubon Naturalist Society detailed for the board the sensitive species of wildlife found in the creek, among them various types of stoneflies and mayflies rarely found elsewhere in the county. Diane Cameron, director of conservation at Audubon Naturalist Society, called Ten Mile Creek “Montgomery County’s last, best creek” and said adding paved surfaces to the area would likely damage it. “As you add new imperviousness to a watershed, what we’ve seen is a decline in stream health,” she said.

Peterson representatives argued, however, that allowing the Tanger project would both help the town center and improve water quality. Taylor Chess, Peterson vice president for retail, said Tanger would not provide direct competition to the town center project and could draw more business to the area. (Peterson, instead, is facing the prospect of intense competition from a project being planned at the former Adventist hospital site.)

Environmental science consultants Loiderman Soltesz & Associates, hired by the developer, told the board that Ten Mile Creek suffered in part because of poor existing storm water management and unregulated discharge pipes they found when inspecting the area. “There’s numerous instances of this,” LSA’s Andie Murtha said.

Chess said the Tanger Outlets would incorporate cutting-edge environmental design to improve water quality. He said the Peterson Cos. have a history of “doing high quality development with a deeply rooted sensitivity for the environment.” Of 38 commercial and six residential properties the company lists in its portfolio, eight have received LEED certification from the U.S. Green Building Council, according to a company spokeswoman.

But the discussion at Ten Mile Creek is likely to remain sensitive, particularly because of the more than 400 building violations the country said it identified at the town center project.

Royce Hanson, a two-time former chairman of the planning board, penned an op-ed last September saying that allowing the new shopping center proposals to go forward “will destroy this sensitive watershed.”

“Proponents of development in the Ten Mile Creek watershed apparently hope that local eagerness for a commercial district will overcome any sense of responsibility for protecting the stream and that decay of official memory will allow town center developers off the hook on which they have placed themselves,” he wrote. “This insult to the environment should not be added to Clarksburg’s manifold injuries.”