Pristine Lake Conceals Filtration Plant

Beneath the idyllic surface of Bridgeport Lake is a complex system of plants and pumps and pipes engineered to collect, scrub and purify the pollution of urbanization.

The multiple functions of the lake as a retention pond, filtration plant and focal feature of a new community required “the most comprehensive effort” his company has ever undertaken, said the lake’s designer, Mark Krebs, president of Pacific Advanced Civil Engineering of Huntington Beach. The 25-year-old company has designed more than 500 lake projects throughout the Southwest and the world, Krebs said.

“Bridgeport Lake is a living biological system designed to replicate nature while being sustained by man’s efforts,” said Krebs, who was also charged with containing the banks of the adjoining Santa Clara River without destroying its natural wild appearance.

The 15-acre lake has a shoreline of nearly three miles that curves like a wet noodle into a series of fingers, allowing a maximum number of waterfront residential lots. In the center is an “island” for 80 homes accessible via two of five bridges, each architecturally unique, that span the lake, which is dotted with waterfalls, fountains and water gardens.

Although a lake club will be exclusive to residents within the development, a wide walkway that is accessible to the public stretches along the north shore, connecting to 25 miles of paseos throughout Santa Clarita.

Many of the lake’s features double as biological functions. For instance, fountains and falls help aerate the water, and around the bottom of the lake, a system of compressors pumps air into pipes that release a steady stream of tiny, cooling bubbles.

Runoff from neighborhood curbside drains is discharged into 24 “wetland treatment cells” spaced around the perimeter of the lake. Resembling giant flowerpots under water, the cells filter incoming runoff through gravel and plants, containing it long enough to remove pollutants, partly through sedimentation, Krebs said.

When runoff flows into the lake, it is further purified by recirculation through a series of 15 biofilters and 40 shallow planters with irises, rushes and other water plants that Krebs said “act as nature’s kidneys.”

Water throughout the lake is recirculated every three to four hours and completely filtered every three days. Microorganisms within the system strip the water of nutrients, such as nitrogen and phosphorous, that otherwise would promote the growth of algae.

A blue color compound, which reduces the amount of light penetration in the relatively shallow water, is also added periodically to counter algae growth, Krebs said. The lake depth averages 8 feet.

“The lake is a living biological system, not a swimming pool that is sterilized,” he said. “So the lake will have seasonal variations, similar to a deciduous tree that drops leaves, has flowers and pollinates.”

Although no chemicals are used, constant maintenance is required to keep its “seasons” in check, Krebs said.

There are no plans to use the lake for swimming or fishing, although Krebs said “nature and people have a way of introducing fish.” Rowboats for the use of residents will be docked at the clubhouse.