Feature- Stream Restoration Saves Water Main And Environment In Valley Forge National Park

A custom-designed and constructed stream restoration project, installed this past Autumn to save a major water main, has won the praises of the National Park Service.

Severe erosion working its way up Thropps Creek in Valley Forge National Historical Park was threatening the stability and function of a 36-inch water main, owned and maintained by Aqua Pennsylvania of Bryn Mawr. Once covered by the creek bed, the exposed water line was now subject to additional stresses and potential failure where it crossed the stream.

Aqua hired Gannett Fleming, Inc., an international engineering consulting firm with offices in Valley Forge, Pa., to solve the problem. They designed a project to raise the streambed from four to six feet using a combination of the existing native streambed material and additional stone. Strategically placed boulders created a series of step-pools through the length of the restoration area to hold the raised bed in place. The design resulted in the water main being reburied three feet under the stream bed.

LandStudies, Inc., an environmental consulting company based in Lititz, Pa., provided most of the construction management and native plant installation for the project because of their well-known expertise in stream and floodplain restoration, wetland creation, and native plant landscape design.

In addition to constructing the series of step-pools, they installed fascines (rough bundles of brushwood used for strengthening an earthen structure), bio-logs, and native grasses and woody plants along the banks to provide additional stabilization and erosion control.

Because of the sensitive location in one of Pennsylvania’s most historic areas, LandStudies used minimally invasive techniques during construction to protect both plants and animals. Only a few trees were removed, and all of them were less than six inches in diameter.

The month-long restoration project was completed in November. The water main is once again protected from the elements, the relevant section of Thropps Creek has been stabilized, and a new community of native plants has been installed along the stream banks.

Michael Caldwell, Valley Forge Park Superintendent, termed the finished project “a remarkable environmental solution to the problem.”

Kristin Civitella, an environmental scientist with Gannett Fleming, noted that “there is not one person who has seen this project who is not completely thrilled with the outcome.”

Mark Gutshall, LandStudies’ director of business development, pointed out that “in many cases where protecting infrastructure is a priority, the surrounding environment suffers. With enough planning and expertise, though, that doesn’t have to be the case.

“The project at Valley Forge,” he continued, “shows how all four partners (Valley Forge National Park, Aqua, Gannett-Fleming, and LandStudies) worked together to find a solution to protect the water main and improve the environment at the project site.”