#lehigh gap

The Lehigh Gap aka the Palmerton Zinc Pile superfund site is a lesson in the importance of continuous management in remediation of toxic lands. The Lehigh Gap was once referred to as a desolate moonscape due to its downwind position from a local Zinc Smelter. From 1889 - 1980 this smelter pumped heavy metals into the air which, due to prevailing winds, landed primarily on this particular mountainside in the Kittatinny Range. Zinc, Cadmium, Lead, sulfuric acid rain turned this area into a hellscape so barren that all the vegetation died. Additionally all 3 feet of top soils washed away; fungi couldn't even survive to decompose dead tree snags whose bark was filled with heavy metals. Due to using an outdated technique, the factory shut down and afterwards the EPA declared the entire region a superfund site in 1983. For the mountainside itself the EPA wanted to incorporate 3 strategies of remediation: Prevent Erosion, Plant only native species to provide habitat for local fauna, and keep the metals under new soils. Originally an ambitious firm followed this strategy by terracing the hillside with roads, they dumped sewage and seeds then left it to grow without management. Quickly the site was flooded with invasive species which no animals could use as habitat and quickly died back down again from acidity.

Gap Circa 2002. The Lehigh Gap Nature Conservancy was formed. The nonprofit bought 700 acres with the intent to remediate the region. A local biology professor involved suggested incorporating lime to neutralize the heavy acidity from the acid rain (the grounds had a Ph 4.2). The area was divided into sections, each location were tested with a slightly different strategies for successful re-establishment of plant communities. [Image below: sign of plant species and mixtures used in specific plots]

The primary methodology was to reestablish plant life and contain the heavy metals using warm season perennial grasses, which would not draw heavy metals up to the top soil and create a layer of humus around the surface toxic metals. They wanted to mirror the plantings of a similar rocky ecosystems: The Serpentine Barrens in Pennsylvania. To keep the metals contained below the new loam the site must be kept in a prairie stage of habitat succession, secondary stages like early birch-aspen forests would draw heavy metals up through its leaves and recontaiminate the topsoil. An indigenous Lenape strategy was utilized keep the prairie at a constant state the same strategy once used to maintain blueberry-huckleberry shrub food forests a couple hundred feet above in the Kittatinny Range.

The result of constant management, occasional burns, public access, native only plantings, and removal of invasives? Success and reduced harm status.

Here we see grasses and flowers provide habitat for hundreds of species, including endanged birds, as well as rare plants such as wild bleeding heart and sandwort

How do we know this was successful and not just natural succession? Unfortunately certain private property owners had their lands containminated as well, some have elected to not allow EPA revitalization due to scape-goating and reactionary politics.

In choosing to leave soils containminated (red barren slopes) the owner of this hill allows heavy metals to flow into the neighborhoods and water ways of the local town as well as eventually the Delaware River. Truly this is despicable behavior as this impacts the health of the entire community.

It was chilly and cloudy day  when a awoke Sunday morning.  I decided to hike on along the Lehigh River near the Lehigh Gap in Carbon County hoping to see some wood ducks in the ponds at the Bowmanstown trail head. or some migrating raptors on the Lehigh and New England Trail . I drove the 25 miles to the Riverview Park in Bowmanstown and walked through the park down to the Lehigh River. There…