Lehman Sanctuary adds swale and rain garden to teaching tools

LEHMAN TWP. — If you’ve visited the Lehman Sanctuary, you know the drill. Start at the top of a hill at the end of a clearing where a long strip of very tall grass blocks much of the view below, and learn how that “prairie grass meadow” is pivotal in protecting the forest wetlands you are about to walk down to.

If you are in one of the guided tours offered to students from area schools, you walk around the grass and down the slope to a world of newts and efts and toads and old trees and heron nests, and much more. But the switch grass is the first lesson. with roots almost as deep as the grass is tall, it stops polluted stormwater from seeping down to the protected forest.

Thanks to a grant from Pennsylvania American Water, visitors will now get an additional lesson before they trek down to the natural treasures waiting for them. The money paid for a grass-line swale and rain garden that further protects against stormwater pollution.

The swale is just that, a shallow open channel designed to direct stormwater to the rain garden, naturally controlling how much water runs to the garden while helping remove some of the pollutants.

The rain garden is “vegetated with flood-tolerant, erosion-resistant plants,” according to a media release from the non-profit sanctuary. It will “become a habitat for wildlife, including pollinators,” and will further filter the stormwater.

While the sanctuary is off a fairly remote stretch of Jackson Road, It is still at risk of all the pollutants that wash off roadways and into neighboring property during a storm. The long ribbon of switch-grass was seeded as a barrier against that risk years ago along the edge of a field where the ground drops dramatically. A drainage pipe now rests near the other end of the field, opening into the swale, which in slopes gently to the rain garden near the grass.

According to the media release, the project completed this month will:

• Collect suburban to rural runoff drainage areas and absorb stormwater from impervious roadways, driveways and homes.

• Allow schools and community groups to learn effective solutions to stormwater runoff by letting students see a rain garden and swale system in the real world, rather than in pictures of classroom models. “Students will also experience vegetation species that are both drought and flood resistant and dragonflies and butterflies and birds actively populating the garden.”

• Add to the already abundant habitats the sanctuary has, while further helping “mammals, amphibians, reptiles, and birds, including Pennsylvania Species of Concern” by maintaining the clean watershed.

The new system also will reduce “peak flow” in the East Branch Harveys Creek running through the wetlands below, helping protect downstream properties from flash flooding. And it will capture sediments, nitrogen and phosphorous in stormwater runoff, helping meat a federal mandate to reduce the flow of such pollutants into waterways.

The sanctuary remains available as a teaching tool to students of all ages, and has drawn inquisitive groups from grade school to college and beyond.